SALT, ACID GENERATOR, RESIST COMPOSITION AND METHOD FOR PRODUCING RESIST PATTERN

Information

  • Patent Application
  • 20240345479
  • Publication Number
    20240345479
  • Date Filed
    April 05, 2024
    8 months ago
  • Date Published
    October 17, 2024
    2 months ago
Abstract
Disclosed are a salt represented by formula (I), an acid generator, a resist composition and the like:
Description
BACKGROUND OF THE INVENTION
Field of the Invention

The present invention relates to a salt, an acid generator, a resist composition and a method for producing a resist pattern.


Description of the Related Art

WO2003/040090 A mentions a salt represented by the following formula.




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SUMMARY OF THE INVENTION

The present invention provides a salt capable of forming a resist pattern with line edge roughness (LER) which is better than that of a resist pattern formed from the resist composition including the salt mentioned above.


The present invention includes the following inventions.


[1] A salt represented by formula (I):




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wherein, in formula (I),

    • X represents a sulfur atom or an iodine atom,
    • R4, R7, R8 and R9 each independently represent a halogen atom or a hydrocarbon group having 1 to 36 carbon atoms, the hydrocarbon group may have a substituent, —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO—, —SO— or —SO2—, and when X is a sulfur atom, R7 and R8 or R8 and R9 may be bonded to form a ring containing S+, R7 and R8 or R8 and R9 that form the ring may be a single bond which is formed between two benzene rings bonded to S+, and —CH2— included in the ring may be replaced by —O—, —S—, —CO—, —SO— or —SO2—,
    • m4 represents an integer of 0 to 5, and when m4 is 2 or more, a plurality of R4 may be the same or different from each other,
    • m7 represents an integer of 0 to 4, and when m7 is 2 or more, a plurality of R7 may be the same or different from each other,
    • m8 represents an integer of 0 to 5, and when m8 is 2 or more, a plurality of R8 may be the same or different from each other,
    • m9 represents an integer of 0 to 5, and when m9 is 2 or more, a plurality of R9 may be the same or different from each other,
    • m10 represents 0 or 1, and when X is a sulfur atom, m10 is 1, and when X is an iodine atom, m10 is 0,
    • Lb1 represents a single bond or an (nb1+1)-valent hydrocarbon group which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—,
    • Lb2 represents a single bond or a divalent hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—,
    • Yb1 represents a methyl group which may have a substituent, or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—, and
    • nb1 represents an integer of 1 to 6, and when nb1 is 2 or more, a plurality of groups in parentheses may be the same or different from each other.


      [2] The salt according to [1], wherein Yb1 represents a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—.


      [3] The salt according to [1] or [2], wherein an anion of the salt represented by formula (I) is an anion represented by formula (I-A1):




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wherein, in formula (I-A1),

    • Lb2 and Yb1 are the same as defined in formula (I),
    • Qb1, Qb2, Qb3 and Qb4 each independently represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms,
    • z1 represents an integer of 0 to 6, and when z1 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
    • X1 represents —O—CO—, —CO—O—, —O—CO—O— or —O—,
    • Lb3 represents single bond or an (nb2+1)-valent hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—, and
    • nb2 represents an integer of 1 to 3, and when nb2 is 2 or more, a plurality of groups in parentheses may be the same or different from each other.


      [4] The salt according to [1] or [2], wherein an anion of the salt represented by formula (I) is an anion represented by formula (I-A2):




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wherein, in formula (I-A2),

    • Lb2 and Yb1 are the same as defined in formula (I),
    • Rb1 represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and —CH2— included in the alkyl group may be replaced by —O— or —CO—,
    • nb4 represents an integer of 1 to 5, and when nb4 is 2 or more, a plurality of groups in parentheses may be the same or different from each other, and
    • nb3 represents an integer of 0 to 4, and when nb3 is 2 or more, a plurality of Rb1 may be the same or different from each other,
    • in which nb4 and nb3 satisfy: 1≤nb4+nb3≤5.


      [5] An acid generator comprising the salt according to any one of [1] to [4].


      [6] A resist composition comprising the acid generator according to [5].


      [7] The resist composition according to [6], further comprising a resin including a structural unit having an acid-labile group, wherein
    • the structural unit having an acid-labile group includes at least one selected from the group consisting of a structural unit represented by formula (a1-0), a structural unit represented by formula (a1-1), a structural unit represented by formula (a1-2), a structural unit represented by formula (a1-4), a structural unit represented by formula (a1-5) and a structural unit represented by formula (a1-6):




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wherein, in formula (a1-0), formula (a1-1) and formula (a1-2),

    • La01, La1 and La2 each independently represent —O— or *—O—(CH2)k1—CO—O—, k1 represents an integer of 1 to 7, and * represents a bonding site to —CO—,
    • Ra01, Ra4 and Ra5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra02, Ra03 and Ra04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups obtained by combining these groups, and the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a halogen atom,
    • Ra6 and Ra7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups obtained by combining these groups,
    • m1′ represents an integer of 0 to 14,
    • n1 represents an integer of 0 to 10, and
    • n1′ represents an integer of 0 to 3:




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wherein, in formula (a1-4),

    • Ra32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra33 represents a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group,
    • Aa30 represents a single bond or *—Xa31-(Aa32-Xa32) and * represents a bonding site to carbon atoms to which —Ra32 is bonded,
    • Aa32 represents an alkanediyl group having 1 to 8 carbon atoms,
    • Xa31 and Xa32 each independently represent —O—, —CO—O— or —O—CO—,
    • nc represents 0 or 1,
    • la represents an integer of 0 to 4, and when la is an integer of 2 or more, a plurality of Ra33 may be the same or different from each other, and
    • Ra34 and Ra35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, Ra36 represents a hydrocarbon group having 1 to 20 carbon atoms, or Ra35 and Ra36 may be bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms together with —C—O— to which Ra35 and Ra36 are bonded, and —CH2— included in the hydrocarbon group and the divalent hydrocarbon group may be replaced by —O— or —S—:




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wherein, in formula (a1-5),

    • RaB represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom,
    • Za1 represents a single bond or *—(CH2)h3—CO-L54-, h3 represents an integer of 1 to 4, and * represents a bonding site to L51,
    • L51, L52, L53 and L54 each independently represent —O— or —S—,
    • s1 represents an integer of 1 to 3, and
    • s1′ represents an integer of 0 to 3, and:




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wherein, in formula (a1-6),

    • Ra61 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra62, Ra63 and Ra64 each independently represent an alkyl group having 1 to 6 carbon atoms or a cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, or Ra62 and Ra63 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with carbon atoms to which Ra62 and Ra63 are bonded,
    • Xa61 represents a single bond, —CO—O—* or —CO—NR5—*, * represents a bonding site to —Ar, and R5 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
    • Xa62 represents a single bond, *—O-La61- or *—CO—O-La62-, * represents a bonding site to —Ar, and La61 and La62 each independently represent an alkanediyl group having 1 to 4 carbon atoms, and
    • Ar represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent.


      [8] The resist composition according to [6] or [7], further comprising a resin including a structural unit having an acid-labile group, wherein
    • the resin including a structural unit having an acid-labile group further includes a structural unit represented by formula (a2-A):




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wherein, in formula (a2-A),

    • Ra2 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Aa21 represents a single bond or an alkanediyl group having 1 to 12 carbon atoms, and —CH2— included in the alkanediyl group may be replaced by —O—, —CO— or —NRa28—, and
    • Ra28 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
    • Xa2 represents a single bond or —CO—,
    • Ra27 represents a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group,
    • nA2 represents an integer of 1 to 5, and when nA2 is 2 or more, a plurality of Xa2 may be the same or different from each other, and
    • nA22 represents an integer of 0 to 4, and when nA22 is 2 or more, a plurality of Ra27 may be the same or different from each other.


      [9] The resist composition according to any one of [6] to [8], further comprising a salt generating an acid having an acidity lower than that of an acid generated from the acid generator.


      [10] A method for producing a resist pattern, which comprises:
    • (1) a step of applying the resist composition according to any one of [6] to [9] on a substrate,
    • (2) a step of drying the applied composition to form a composition layer,
    • (3) a step of exposing the composition layer,
    • (4) a step of heating the exposed composition layer, and
    • (5) a step of developing the heated composition layer.


It is possible to produce a resist pattern with satisfactory line edge roughness (LER) by using a resist composition including the salt of the present invention.







DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, “(meth)acrylic monomer” means “at least one of acrylic monomer and methacrylic monomer”. Notations such as “(meth)acrylate” and “(meth)acrylic acid” mean the same thing. In groups mentioned herein, regarding groups capable of having both a linear structure and a branched structure, they may have either the linear or branched structure. When —CH2— included in the hydrocarbon group or the like is replaced by —O—, —S—, —CO— or —SO2—, the same examples shall apply for each group, and the number of carbon atoms before replacement is taken as the total number of the hydrocarbon group. “Combined group” means a group in which two or more exemplified groups are bonded, and valences of those groups may be appropriately varied by bonding forms. “Derived” or “Induced” means that a polymerizable C═C bond included in the molecule becomes a —C—C— group (single bond) by polymerization. When stereoisomers exist, all stereoisomers are included. Hydrogen atoms at any position and any number of hydrogen atoms included in each group may be sometimes replaced by a bond depending on the number of substituents or the like. The number of carbon atoms in the substituents is not included in the number of carbon atoms in the group to be substituted. The acid-labile group means a group in which a leaving group is eliminated by contact with an acid (e.g., trifluoromethanesulfonic acid), thus forming a hydrophilic group (e.g. a carboxy group or a hydroxy group). The base-labile group means a group in which a leaving group is eliminated by contact with a base (e.g., trimethylamine), thus forming a hydrophilic group (e.g. a carboxy group or a hydroxy group).


As used herein, “solid component of the resist composition” means the total amount of components in which the below-mentioned solvent (E) is removed from the total amount of the resist composition.


[Salt Represented by Formula (I)]

The present invention relates to a salt represented by formula (I) (hereinafter sometimes referred to as “salt (I)”).


Of the salt (I), the side having positive charge is sometimes referred to as “cation (I)”, and the side having negative charge is sometimes referred to as “anion (I)”:


[Cation (I)]

The cation (I) of the salt represented by formula (I) is a cation represented by formula (I-C):




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wherein, in formula (I-C), all symbols are the same as defined in formula (I).


Examples of the halogen atom as for R4, R7, R8 and R9 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the hydrocarbon group having 1 to 36 carbon atoms as for R4, R7, R8 and R9 include chain hydrocarbon groups such as an alkyl group and an alkanediyl group, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these groups. The number of carbon atoms of the hydrocarbon group is preferably 1 to 30, more preferably 1 to 24, and still more preferably 1 to 18.


The alkyl group is a linear or branched alkyl group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, an octyl group, a nonyl group, a decyl group, an undecyl group and a dodecyl group.


The alkanediyl group is a linear or branched alkanediyl group, and examples thereof include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group and a hexane-1,6-diyl group; and

    • branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group.


The number of carbon atoms of the chain hydrocarbon group is preferably 1 to 18, more preferably 1 to 12, still more preferably 1 to 9, yet more preferably 1 to 6, further preferably 1 to 4, and still further preferably 1 to 3.


The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples thereof include groups shown below. The bonding site can be any position.




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Specific examples of the monocyclic alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group and a cyclododecyl group. Examples of the polycyclic alicyclic hydrocarbon group include polycyclic cycloalkyl groups such as a decahydronaphthyl group, an adamantyl group and a norbornyl group, and spiro rings having a cycloalkayl group, a norbornyl group or an adamantyl group and a cycloalkyl group spiro-bonded to each group, such as a spirocyclohexane-1,2′-cyclopentane group or a spiroadamantane-2,3′-cyclopentane group. The number of carbon atoms of the alicyclic hydrocarbon group is preferably 3 to 18, more preferably 3 to 16, and still more preferably 3 to 12.


Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a binaphthyl group and the like. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 to 18, more preferably 6 to 14, and still more preferably 6 to 10.


Examples of the groups formed by combining two or more groups of a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group include groups formed by combining an aromatic hydrocarbon group with a chain hydrocarbon group (e.g., aromatic hydrocarbon group-alkanediyl group-*, alkyl group-aromatic hydrocarbon group-*, alkyl group-aromatic hydrocarbon group-alkanediyl group-*), groups formed by combining an alicyclic hydrocarbon group with a chain hydrocarbon group (e.g., alicyclic hydrocarbon group-alkanediyl group-*, alkyl group-alicyclic hydrocarbon group-*, alkyl group-alicyclic hydrocarbon group-alkanediyl group-*) and groups formed by combining an aromatic hydrocarbon group with an alicyclic hydrocarbon group (e.g., aromatic hydrocarbon group-alicyclic hydrocarbon group-*, alicyclic hydrocarbon group-aromatic hydrocarbon group-*). In the above groups, —CH2— included in the alicyclic hydrocarbon group, the alkanediyl group and the alkyl group may be replaced by —O—, —S—, —CO—, —SO— or —SO2—. * represents a bonding site.


Examples of the aromatic hydrocarbon group-alkanediyl group-* include aralkyl groups such as a benzyl group and a phenethyl group.


Examples of the alkyl group-aromatic hydrocarbon group-* include a tolyl group, a xylyl group, a cumenyl group and the like.


Examples of the alicyclic hydrocarbon group-alkanediyl group-* include cycloalkylalkyl groups such as a cyclohexylmethyl group, a cyclohexylethyl group, a 1-(adamantan-1-yl)methyl group and a 1-(adamantan-1-yl)-1-methylethyl group.


Examples of the alkyl group-alicyclic hydrocarbon group-* include cycloalkyl groups having an alkyl group, such as a methylcyclohexyl group, a dimethylcyclohexyl group and a 2-alkyladamantan-2-yl group.


Examples of the aromatic hydrocarbon group-alicyclic hydrocarbon group-* include a phenylcyclohexyl group and the like.


Examples of the alicyclic hydrocarbon group-aromatic hydrocarbon group-* include a cyclohexylphenyl group and the like.


In combination, two or more of alicyclic hydrocarbon groups, aromatic hydrocarbon groups and chain hydrocarbon groups may be respectively combined. Any group may also be bonded to the benzene ring.


When —CH2— included in the hydrocarbon group represented by R4, R7, R8 and R9 is replaced by —O—, —CO—, —S—, —SO— or —SO2—, the number of carbon atoms before replacement is taken as the total number of the hydrocarbon group. The number may be either 1, or 2 or more.


Examples of the group in which —CH2— included in the hydrocarbon group is replaced by —O—, —CO—, —S—, —SO— or —SO2— include a hydroxy group (a group in which —CH2— included in the methyl group is replaced by —O—), a thiol group (a group in which —CH2— included in the methyl group is replaced by —S—), a carboxy group (a group in which —CH2—CH2— included in the ethyl group is replaced by —O—CO—), an alkoxy group (a group in which —CH2— at any position included in the alkyl group is replaced by —O—), an alkoxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —O—CO—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —CO—O—), an alkylthio group (a group in which —CH2— at any position included in the alkyl group is replaced by —S—), an alkylsulfyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —SO—), an alkylsulfonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —SO2—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), a thio group (a group in which —CH2— included in the methylene group is replaced by —S—), a sulfyl group (a group in which —CH2— included in the methylene group is replaced by —SO—), a sulfonyl group (a group in which —CH2— included in the methylene group is replaced by —SO2—), an alkanediyloxy group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —O—), an alkanediyloxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —CO—), an alkanediylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —CO—O—), an alkanediylthio group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —S—), an alkanediylsulfyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —SO—), an alkanediylsulfonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —SO2—), a cycloalkoxy group, a cycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatic hydrocarbon group-carbonyloxy group, an aromatic hydrocarbon group-carbonyl group, an aromatic hydrocarbon group-oxy group, a haloalkoxy group (a group in which —CH2— at any position included in the haloalkyl group is replaced by —O—), a haloalkoxycarbonyl group (a group in which —CH2—CH2— at any position included in the haloalkyl group is replaced by —O—CO—), a haloalkylcarbonyl group (a group in which —CH2— at any position included in the haloalkyl group is replaced by —CO—), a haloalkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the haloalkyl group is replaced by —CO—O—), and groups obtained by combining two or more of these groups.


Examples of the alkoxy group include alkoxy groups having 1 to 35 carbon atoms, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group and the like. The number of carbon atoms of the alkoxy group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


The alkoxycarbonyl group, the alkylcarbonyl group and the alkylcarbonyloxy group represent a group in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.


Examples of the alkoxycarbonyl group include alkoxycarbonyl groups having 2 to 35 carbon atoms, for example, a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group and the like. Examples of the alkylcarbonyl group include alkylcarbonyl groups having 2 to 36 carbon atoms, for example, an acetyl group, a propionyl group and a butyryl group. Examples of the alkylcarbonyloxy group include alkylcarbonyloxy groups having 2 to 35 carbon atoms, for example, an acetyloxy group, a propionyloxy group, a butyryloxy group and the like. The number of carbon atoms of the alkoxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3. The number of carbon atoms of the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3. The number of carbon atoms of the alkylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3.


Examples of the alkylthio group include alkylthio groups having 1 to 35 carbon atoms, for example, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, an octylthio group, a 2-ethylhexylthio group, a nonylthio group, a decylthio group, an undecylthio group and the like. The number of carbon atoms of the alkylthio group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkylsulfyl group include alkylsulfyl groups having 1 to 35 carbon atoms, for example, a methylsulfyl group, an ethylsulfyl group, a propylsulfyl group, a butylsulfyl group, a pentylsulfyl group, a hexylsulfyl group, an octylsulfyl group, a 2-ethylhexylsulfyl group, a nonylsulfyl group, a decylsulfyl group, an undecylsulfyl group and the like. The number of carbon atoms of the alkylsulfyl group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkylsulfonyl group include alkylsulfonyl groups having 1 to 35 carbon atoms, for example, a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, a butylsulfonyl group, a pentylsulfonyl group, a hexylsulfonyl group, an octylsulfonyl group, a 2-ethylhexylsulfonyl group, a nonylsulfonyl group, a decylsulfonyl group, an undecylsulfonyl group and the like. The number of carbon atoms of the alkylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkanediyloxy group include alkanediyloxy groups having 1 to 35 carbon atoms, for example, a methyleneoxy group, an ethyleneoxy group, a propanediyloxy group, a butanediyloxy group, a pentanediyloxy group and the like. The number of carbon atoms of the alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkanediyloxycarbonyl group include alkanediyloxycarbonyl groups having 2 to 35 carbon atoms, for example, a methyleneoxycarbonyl group, an ethyleneoxycarbonyl group, a propanediyloxycarbonyl group, a butanediyloxycarbonyl group and the like. Examples of the alkanediylcarbonyl group include alkanediylcarbonyl groups having 2 to 36 carbon atoms, for example, a methylenecarbonyl group, an ethylenecarbonyl group, a propanediylcarbonyl group, a butanediylcarbonyl group, a pentanediylcarbonyl group and the like. Examples of the alkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having 2 to 35 carbon atoms, for example, a methylenecarbonyloxy group, an ethylenecarbonyloxy group, a propanediylcarbonyloxy group, a butanediylcarbonyloxy group and the like. The number of carbon atoms of the alkanediyloxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3. The number of carbon atoms of the alkanediylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3. The number of carbon atoms of the alkanediylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 or 3.


Examples of the alkanediylthio group include alkanediylthio groups having 1 to 35 carbon atoms, for example, a methylenethio group, an ethylenethio group, a propylenethio group and the like. The number of carbon atoms of the alkanediylthio group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkanediylsulfyl group include alkanediylsulfyl groups having 1 to 35 carbon atoms, for example, a methylenesulfyl group, an ethylenesulfyl group, a propylenesulfyl group and the like. The number of carbon atoms of the alkanediylsulfyl group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkanediylsulfonyl group include alkanediylsulfonyl groups having 1 to 35 carbon atoms, for example, a methylenesulfonyl group, an ethylenesulfonyl group, a propylenesulfonyl group and the like. The number of carbon atoms of the alkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the cycloalkoxy group include cycloalkoxy groups having 3 to 35 carbon atoms, for example, a cyclohexyloxy group and the like. Examples of the cycloalkylalkoxy group include cycloalkylalkoxy groups having 4 to 35 carbon atoms, for example, a cyclohexylmethoxy group and the like. Examples of the alkoxycarbonyloxy group include alkoxycarbonyloxy groups having 2 to 34 carbon atoms, for example, a butoxycarbonyloxy group and the like. Examples of the aromatic hydrocarbon group-carbonyloxy group include aromatic hydrocarbon group-carbonyloxy groups having 7 to 36 carbon atoms, for example, a benzoyloxy group and the like. Examples of the aromatic hydrocarbon group-carbonyl group include aromatic hydrocarbon group-carbonyl groups having 7 to 36 carbon atoms, for example, a benzoyl group and the like. Examples of the aromatic hydrocarbon group-oxy group include aromatic hydrocarbon group-oxy groups having 6 to 35 carbon atoms, for example, a phenyloxy group and the like.


Examples of the group in which —CH2— included in the alicyclic hydrocarbon group is replaced by —O—, —S—, —SO2— or —CO— include the following groups. It is also possible to exemplify, as the following groups, groups in which —O— is replaced by —S— and —CO— is replaced by —SO— or —SO2—, respectively. The bonding site can be any position.




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Examples of the substituent which may be possessed by the hydrocarbon group as for R4, R7, R8 and R9 include a halogen atom, a cyano group, a nitro group and the like.


Examples of the halogen atom include the same groups as mentioned above.


When R4, R7, R8 and R9 are a hydrocarbon group having a halogen atom, examples of the hydrocarbon group having a halogen atom as for R4, R7, R8 and R9 include a chain hydrocarbon group (an alkyl group, etc.) having a halogen atom, an alicyclic hydrocarbon group having a halogen atom, and an aromatic hydrocarbon group having a halogen atom.


Examples of the alkyl group having halogen include haloalkyl groups having 1 to 12 carbon atoms, for example, an alkyl fluoride group having 1 to 12 carbon atoms, an alkyl chloride group having 1 to 12 carbon atoms, an alkyl bromide group having 1 to 12 carbon atoms, an alkyl iodide group having 1 to 12 carbon atoms and the like. Examples of the haloalkyl group include a perfluoroalkyl group having 1 to 12 carbon atoms (a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, etc.), a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group and the like. The number of carbon atoms of the haloalkyl group is preferably 1 to 9, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


—CH2— included in the haloalkyl group may be replaced by —O— or —CO— and, for example, a haloalkoxy group, a haloalkoxycarbonyl group, a haloalkylcarbonyl group, a haloalkylcarbonyloxy group and the like are exemplified. Specific examples thereof include a haloalkoxy group having 1 to 11 carbon atoms, a haloalkoxycarbonyl group having 2 to 11 carbon atoms, a haloalkylcarbonyl group having 2 to 12 carbon atoms, a haloalkylcarbonyloxy group having 2 to 11 carbon atoms and the like, for example, groups in which one or more hydrogen atoms of the above-mentioned groups are substituted with a halogen atom.


The hydrocarbon group may have one or a plurality of substituents.


m4 is preferably 0, 1, 2, 3 or 5, and more preferably 0, 1, 2 or 3.


When m4 is an integer of 1 or more, the bonding site to the benzene ring of R4 may be the o-position, the m-position or the p-position, with respect to the bonding site of the benzene ring to which X+ is bonded. When m4 is 1 or 2, R4 is preferably bonded at the p-position or the m-position, with respect to the bonding site of the benzene ring to which X+ is bonded. When m4 is 3 or more, at least one of R4 is preferably bonded at the o-position or the m-position, with respect to the bonding site of the benzene ring to which X+ is bonded.


The bonding site of the benzene ring to which R4 is bonded may be the o-position, the m-position or the p-position in the benzene ring to which X+ is bonded, with respect to the bonding site of X+. Particularly, the benzene ring to which R4 is bonded is preferably bonded at the p-position or the m-position, and more preferably at the p-position, with respect to the bonding site of X+.


m7 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


When m7 is an integer of 1 or more, the bonding site to the benzene ring of R7 may be the o-position, the m-position or the p-position, with respect to the bonding site of X+. Particularly, at least one of R7 is preferably bonded at the o-position or the m-position, and more preferably at the m-position, with respect to the bonding site of X+.


m8 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


m9 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


When at least one of m8 and m9 is an integer of 1 or more, the bonding site to the benzene ring of R8 and/or R9 may be the o-position, the m-position or the p-position, with respect to the bonding site of X+. Particularly, at least one of R8 and/or R9 is preferably bonded at the m-position or the p-position, and more preferably at the p-position, with respect to the bonding site of X+.


R4 is preferably a halogen atom or an alkyl group having 1 to 12 carbon atoms which may have a halogen atom (—CH2— included in the alkyl group may be replaced by —O— or —CO—), more preferably a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a fluorine atom (—CH2— included in the alkyl group may be replaced by —O— or —CO—), still more preferably a halogen atom, an alkyl fluoride group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms (—CH2— included in the alkyl fluoride group and the alkyl group may be replaced by —O— or —CO—), further preferably a fluorine atom, a bromine atom, an iodine atom, a perfluoroalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), and still further preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a hydroxy group, a methoxy group, a methyl group or a t-butyl group.


Preferably, R7, R8 and R9 are each independently a halogen atom or an alkyl group having 1 to 12 carbon atoms which may have a halogen atom (—CH2— included in the alkyl group may be replaced by —O— or —CO—), more preferably a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a fluorine atom (—CH2— included in the alkyl group may be replaced by —O— or —CO—), still more preferably a halogen atom, an alkyl fluoride group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms (—CH2-included in the alkyl fluoride group and the alkyl group may be replaced by —O— or —CO—), further preferably a fluorine atom, a bromine atom, an iodine atom, a perfluoroalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), and still further preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a hydroxy group, a methoxy group, a methyl group or a t-butyl group.


Specific examples of the cation represented by formula (I-C) include a cation represented by formula (I-C-1) or formula (I-C-2) (hereinafter sometimes referred to as “cation (I-C-1)” and “cation (I-C-2)”, respectively):




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wherein all symbols are the same as defined above.


When X is a sulfur atom and m10=1, R7 and R8 or R8 and R9 may be bonded to form a ring containing S+. Particularly, R8 and R9 are preferably bonded to form a ring containing S+, and the cation is preferably a cation represented by formula (I-C′):




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wherein symbols other than X7 are the same as defined above, respectively.


X7 represents a single bond, —CH2—, —O—, —CO—, —SO—, —SO2— or —S—.


X7 preferably represents a single bond, —CH2— or —O—.


Examples of the cation of the salt (I) include cations represented by the following formula (I-c-1) to formula (I-c-80) and the like.




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[Anion (I)]

The anion (I) of the salt represented by formula (I) is an anion represented by formula (I-A):




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wherein all symbols are the same as defined above.


Examples of the (nb1+1)-valent hydrocarbon group as for Lb1 include groups which are obtained by removing nb1 hydrogen atoms from a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group, and a monovalent group formed by combining two or more of these groups, and bonding to one or more Lb2.


The number of carbon atoms of the hydrocarbon group is preferably 1 to 48, more preferably 1 to 42, still more preferably 1 to 36, yet more preferably 1 to 30, and further preferably 1 to 24.


Examples of the chain hydrocarbon group include groups obtained by removing nb1 hydrogen atoms of the alkyl group or alkenyl group. The alkyl group may be either linear or branched, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentanedecyl group, a heptadecyl group and the like. Examples of the alkenyl group include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, an isooctenyl group and a nonenyl group.


The number of carbon atoms of the chain hydrocarbon group is preferably 1 to 36, more preferably 1 to 24, still more preferably 1 to 20, yet more preferably 1 to 18, further preferably 1 to 12, and still further preferably 1 to 10.


Examples of the alicyclic hydrocarbon group include groups obtained by removing nb1 hydrogen atoms of the monocyclic or polycyclic cycloalkyl group. Examples of the monocyclic cycloalkyl group include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like.


Examples of the polycyclic cycloalkyl group include a cycloalkyl group having a crosslinked structure, a cycloalkyl group in which two or more rings are fused, or a cycloalkyl group in which two rings are bonded by spiro bonding. Examples of the cycloalkyl group having a crosslinked structure include a norbornyl group, an adamantyl group and the like. Examples of the cycloalkyl group in which two or more rings are fused include a bicyclo[4,4,0]decane group, a steroid group (steroid skeleton) and the like. Examples of the cycloalkyl group in which two rings are bonded by spiro bonding include a spirocyclic cycloalkyl group in which one cycloalkyl group selected from the group consisting of a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group, and a cycloalkyl group having 5 to 8 carbon atoms are bonded by spiro bonding, and the like. A double bond may be formed between two carbon atoms included in the alicyclic hydrocarbon group.


More specifically, alicyclic hydrocarbon groups represented by the following formulas are exemplified.




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When the alicyclic hydrocarbon group is a monocyclic cycloalkyl group, the number of carbon atoms of the alicyclic hydrocarbon group is preferably 3 to 24, more preferably 3 to 20, still more preferably 3 to 18, yet more preferably 3 to 12, further preferably 3 to 10, and still further preferably 3 to 8. When the alicyclic hydrocarbon group is a polycyclic cycloalkyl group, the number of carbon atoms of the alicyclic hydrocarbon group is preferably 6 to 24, more preferably 6 to 20, still more preferably 6 to 18, and yet more preferably 6 to 12, and further preferably 7 to 12.


Examples of the aromatic hydrocarbon group include groups obtained by removing nb1 hydrogen atoms of the aryl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a fluorenyl group and the like.


More specifically, aromatic hydrocarbon groups represented by the following formulas are exemplified.




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The number of carbon atoms of the aromatic hydrocarbon group is preferably 4 to 24, more preferably 4 to 20, still more preferably 4 to 18, yet more preferably 5 to 14, and further preferably 5 to 10, and still further preferably 6 to 10.


When —CH2— included in the hydrocarbon group as for Lb1 is replaced by —O—, —CO—, —S— or —SO2—, the number of carbon atoms before replacement is taken as the number of carbon atoms of the hydrocarbon group.


Of the hydrocarbon group as for Lb1, examples of the group in which —CH2— included in the chain hydrocarbon group is replaced by —O—, —CO—, —S— or —SO2— include a hydroxy group (a group in which —CH2— included in the methyl group is replaced by —O—), a carboxy group (a group in which —CH2—CH2— included in the ethyl group is replaced by —O—CO—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), an alkoxy group (a group in which —CH2— at any position included in the alkyl group is replaced by —O—), an alkoxycarbonyl group (a group in which —CH2—CH2— at any position included in alkyl group is replaced by —O—CO—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —CO—O—), an alkanediyloxy group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —O—), an alkanediyloxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —CO—), an alkanediylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —CO—O—) and the like. Examples of these replaced groups include the same groups as mentioned herein as long as the upper limit of the number of carbon atoms permits.


Of the hydrocarbon group as for Lb1, examples of the group in which —CH2— included in the alicyclic hydrocarbon group is replaced by —O—, —CO—, —S— or —SO2— include groups having a structure such as cyclic ether, cyclic ketone, cyclic ester (lactone), cyclic thioether, cyclic acetal or cyclic sulfonic acid ester (sultone). Specific examples thereof include alicyclic hydrocarbon groups represented by the following formulas. The bonding site of the alicyclic hydrocarbon group represented by the following formulas can be any position.




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Of the hydrocarbon group as for Lb1, —CH2— included in the aromatic hydrocarbon group may be replaced by —O— or —S—, and examples of the group in which —CH2— is replaced by —O— or —S— include groups derived from a furan ring or a thiophene ring, respectively. Specific examples thereof include aromatic hydrocarbon groups represented by the following formulas.




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Examples of the group obtained by combining two or more groups of the chain hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group include a group obtained by combining the chain hydrocarbon group with the alicyclic hydrocarbon group, a group obtained by combining the chain hydrocarbon group with the aromatic hydrocarbon group, a group obtained by combining the alicyclic hydrocarbon group with the aromatic hydrocarbon group, a group obtained by combining the chain hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group. The group obtained by combining the alicyclic hydrocarbon group with the aromatic hydrocarbon group may also be a fused ring.


Examples of the divalent hydrocarbon group as for Lb2 include a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbon group, and groups obtained by combining two or more of these groups, and groups which are obtained by removing one hydrogen atom from a monovalent hydrocarbon group, and bonding to Yb1.


Examples of the divalent chain hydrocarbon group, the divalent alicyclic hydrocarbon group, the divalent aromatic hydrocarbon group, and the divalent group obtained by combining two or more of these groups as for Lb2 include groups obtained by removing one hydrogen atom from the monovalent chain hydrocarbon group, the monovalent alicyclic hydrocarbon group, the monovalent aromatic hydrocarbon group, and the monovalent group formed by combining two or more of these groups mentioned as for Lb1, respectively, as long as the upper limit of the number of carbon atoms permits.


The hydrogen atom included in the hydrocarbon group as for Lb1 and Lb2 may be substituted with a substituent. Examples of the substituent which may be possessed by the hydrocarbon group as for Lb1 and Lb2 include a halogen atom, a cyano group, a nitro group and the like.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.


When Lb1 and Lb2 are groups obtained by combining an alicyclic hydrocarbon group or an aromatic hydrocarbon group with a chain hydrocarbon group, the chain hydrocarbon group may be substantially regarded as a substituent which is possessed by the alicyclic hydrocarbon group or the aromatic hydrocarbon group. By replacing —CH2— of the chain hydrocarbon group included in the hydrocarbon group as for Lb1 and Lb2 by —O—, —CO—, —S— or —SO2—, the hydrocarbon group as for Lb1 and Lb2 can substantially have a substituent such as a hydroxy group, a carboxy group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a thiol group or a sulfonyl group.


The number of substituents which may be possessed by Lb1 and Lb2 is not particularly limited, and they may have a plurality of substituents.


Examples of the cyclic hydrocarbon group as for Yb1 include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups obtained by combining an alicyclic hydrocarbon group with an aromatic hydrocarbon group.


Examples of the alicyclic hydrocarbon group and the aromatic hydrocarbon group as for Yb1 include same alicyclic hydrocarbon groups and aromatic hydrocarbon groups as mentioned as for Lb1, respectively, and when having no substituent, they may be a monovalent alicyclic hydrocarbon group and a monovalent aromatic hydrocarbon group.


Examples of the substituent which may be possessed by the methyl group as for Yb1 include a halogen atom, a hydroxy group, a cyano group, a nitro group and the like.


Examples of the substituent which may be possessed by the cyclic hydrocarbon group as for Yb1 include a halogen atom, a cyano group, a nitro group, or a hydrocarbon group having 1 to 18 carbon atoms which may have a halogen atom, a cyano group or a nitro group (—CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—).


Examples of the halogen atom include the same halogen atoms as those mentioned as the substituent as for Lb1 and Lb2.


Examples of the hydrocarbon group having 1 to 18 carbon atoms which may be possessed, as the substituent, by the cyclic hydrocarbon group as for Yb1 include a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups obtained by combining these groups. Examples of the chain hydrocarbon group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and groups obtained by combining two or more of these groups include the same groups as mentioned in the chain hydrocarbon group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and groups obtained by combining two or more of these groups as for Lb1 as long as the upper limit of the number of carbon atoms permit. Examples of the group in which —CH2— included in the hydrocarbon group having 1 to 18 carbon atoms is replaced by —O—, —S—, —CO— or —SO2— which may be possessed, as the substituent, by the cyclic hydrocarbon group as for Yb1 include the same groups as mentioned in the group in which —CH2— included in the hydrocarbon group is replaced by —O—, —S—, —CO— or —SO2— as for Lb1 as long as the upper limit of the number of carbon atoms permit. The hydrocarbon group having 1 to 18 carbon atoms which may be possessed, as the substituent, by the cyclic hydrocarbon group as for Yb1 may constitute a protecting group or a leaving group (an acid-labile group or a base-labile group) which is generally used in the relevant field.


Examples of the anion represented by formula (I-A) include an anion represented by formula (I-A1) (hereinafter sometimes referred to as anion (I-A1)”) and an anion represented by formula (I-A2) (hereinafter sometimes referred to as “anion (I-A2)”).


(Anion (I-A1))

The anion represented by formula (I-A1) is represented by the following formula:




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wherein, in formula (I-A1), all symbols are the same as defined above.


Examples of the alkyl group as for Qb1, Qb2, Qb3 and Qb4 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group.


Examples of the perfluoroalkyl group as for Qb1, Qb2, Qb3 and Qb4 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group and a perfluorohexyl group.


Qb1 and Qb2 preferably includes a fluorine atom or a perfluoroalkyl group in at least one of Qb1 and Qb2, more preferably a fluorine atom or a perfluoroalkyl group, still more preferably a fluorine atom or a trifluoromethyl group, and yet more preferably both are fluorine atoms.


Preferably, Qb3 and Qb4 are each independently a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 3 carbon atoms, Qb3 is preferably a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 3 carbon atoms, and Qb4 is preferably a hydrogen atom or a fluorine atom.


z1 is preferably an integer of 0 to 3, and more preferably 0, 1 or 2.


X1 is preferably —O—CO— or —CO—O—.


Examples of the hydrocarbon group in Lb3 include the same hydrocarbon groups as mentioned as for Lb1 of formula (I-A) as long as the upper limit of the number of carbon atoms permit.


Lb3 is preferably a single bond, a chain hydrocarbon group having 1 to 12 carbon atoms which may have a substituent (—CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—), an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (—CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—), an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a substituent (—CH2— included in the aromatic hydrocarbon group may be replaced by —O— or —S—) or groups obtained by combining two or more of these groups, and more preferably a single bond, a chain hydrocarbon group having 1 to 6 carbon atoms, or a group represented by the following formula (Lb3-1). When —CH2— included in the chain hydrocarbon group is replaced by —O— or —CO—, the number thereof is preferably 1 to 4, and one —CH2—CH2— included in the chain hydrocarbon group is preferably replaced by —O—CO— or —CO—O—, or one —CH2—CH2—CH2— included in the chain hydrocarbon group is preferably replaced by —O—CO—O—:




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wherein, in formula (Lb3-1),

    • nb2 is the same as defined in formula (I-A1),
    • Lb31 represents a single bond or a chain hydrocarbon group having 1 to 12 carbon atoms, —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—, and the chain hydrocarbon group may have a substituent,
    • Wb3 represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms, —CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—, —CH2— included in the aromatic hydrocarbon group may be replaced by —O— or —S—, and the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent, and
    • * and ** represent a bonding site, and * represents a bonding site to X1.


In formula (Lb3-1), examples of the chain hydrocarbon group as for Lb31 include the same chain hydrocarbon groups as mentioned as for Lb1 as long as the upper limit of the number of carbon atoms permit.


In formula (Lb3-1), examples of the alicyclic hydrocarbon group and the aromatic hydrocarbon group as for Wb3 include the same alicyclic hydrocarbon groups and aromatic hydrocarbon groups as mentioned as for Lb1 as long as the upper limit of the number of carbon atoms permit.


In formula (Lb3-1), examples of the substituent which may be possessed by the chain hydrocarbon group as for Lb31 and the substituent which may be possessed by the alicyclic hydrocarbon group and the aromatic hydrocarbon group as for Wb1 include the same substituents as mentioned as for the substituent which may be possessed by the hydrocarbon group as for Lb1.


Lb31 is preferably a single bond or an alkanediyl group having 1 to 6 carbon atoms (—CH2— included in the alkanediyl group may be replaced by —O— or —CO—).


Particularly, the alicyclic hydrocarbon group and the aromatic hydrocarbon group as for Wb3 are preferably an alicyclic hydrocarbon group and an aromatic hydrocarbon group mentioned below. In the alicyclic hydrocarbon group and the aromatic hydrocarbon group mentioned below, * and ** represent a bonding site, * represents a bonding site to X1 or Lb31, ** represents a bonding site to a hydrogen atom, a substituent or Lb2, and at least one ** represents a bonding site to Lb2. In the alicyclic hydrocarbon group mentioned below, —CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—. When —CH2— included in the alicyclic hydrocarbon group is replaced by —O—, —S—, —CO— or —SO2—, it is preferable to form an ether ring, an ester ring (lactone), a carbonic acid ester ring, a sulfonic acid ester ring (sultone) or an acetal ring.




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In formula (I-A1), Lb2 is preferably a single bond or a chain hydrocarbon group having 1 to 12 carbon atoms (—CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—), and more preferably a single bond, —O—, —O—CO—, —CO—O—, —O—CO—O— or *-Lb21-X2-Lb22-** (one of Lb21 and Lb22 represents a chain hydrocarbon group having 1 to 6 carbon atoms, and the other one represents a single bond or a chain hydrocarbon group having 1 to 6 carbon atoms, X2 represents —O—, —CO—O—, —O—CO— or —O—CO—O—, * and ** represent a bonding site, and ** represents a bonding site to Yb1, in which the total number of carbon atoms of Lb21, X2 and Lb22 is 12 or less).


In formula (I-A1), Yb1 is preferably a cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent (—CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—), more preferably, an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (—CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—) or an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and still more preferably an alicyclic hydrocarbon group having 3 to 16 carbon atoms which may have a substituent (—CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—) or an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a substituent. Specifically, groups represented by the following formula (Y1) to formula (Y36) are preferable. In formula (Y1) to formula (Y36), RYb represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms of substituents which may be possessed by the cyclic hydrocarbon group as for Yb1, RYc represents a hydrogen atom or a substituent which may be possessed by the cyclic hydrocarbon group as for Yb1, and * represents a bonding site to Lb2. The alicyclic hydrocarbon group and the aromatic hydrocarbon group represented by the following formula (Y1) to formula (Y36) are not particularly shown in the following formulas, but may have any other substituents.




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The anion represented by formula (I-A1) is preferably an anion represented by formula (I-A1-1) to formula (I-A1-85) [hereinafter sometimes referred to as “anion (I-A1-1)” or the like according to the number of formula number], and more preferably an anion represented by any one of formula (I-A1-1) to formula (I-A1-4), formula (I-A1-9), formula (I-A1-10), formula (I-A1-24) to formula (I-A1-33), formula (I-A1-36) to formula (I-A1-40) and formula (I-A1-47) to formula (I-A1-85).




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Here, R12 to R17 are each independently, for example, an alkyl group having 1 to 4 carbon atoms, and preferably a methyl group or an ethyl group. R18 is, for example, a chain hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or groups formed by combining these groups, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. LA41 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Qb1 and Qb2 are the same as defined above.


Specific examples of the anion represented by formula (I-A1) include anions mentioned in JP 2010-204646 A.


Examples of the anion represented by formula (I-A1) preferably include anions represented respectively by formula (I-a-1) to formula (I-a-70). Of these, an anion represented by any one of formula (I-a-1) to formula (I-a-4), formula (I-a-7) to formula (I-a-11), formula (I-a-14) to formula (I-a-30) and formula (I-a-35) to formula (I-a-70) is preferable.




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(Anion (I-A2))

The anion represented by formula (I-A2) is represented by the following formula:




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wherein, in formula (I-A2), all symbols are the same as defined above.


In formula (I-A2), examples of the hydrocarbon group as for Lb2 and the cyclic hydrocarbon group as for Yb1 include the same hydrocarbon groups as for Lb2 and the same cyclic hydrocarbon groups as for Yb1 in formula (I-A) as long as the upper limit of the number of carbon atoms permit. Examples of the substituent which may be possessed by the hydrocarbon group as for Lb2, and the methyl group and the cyclic hydrocarbon group as for Yb2 also include the same substituents which may be possessed by the hydrocarbon groups as for Lb2, and the methyl group and the cyclic hydrocarbon group as for Yb1 of formula (I-A).


In formula (I-A2), Lb2 is preferably a chain hydrocarbon group having 1 to 12 carbon atoms (—CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—), and more preferably *—CO—O-Lb41- (Lb41 is a single bond or a chain hydrocarbon group having 1 to 6 carbon atoms, —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—, * represents a bonding site to the benzene ring to which 503 is bonded, and Lb41 is preferably a single bond or a chain hydrocarbon group having 1 to 3 carbon atoms). In formula (I-A2), Yb1 is preferably a cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent (—CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—), more preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (—CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—) or an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and still more preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group exemplified as for Yb1 or Lb1 of formula (I-A1). Specifically, groups represented by formula (Y1) to formula (Y36) mentioned above are preferable, and groups represented by formula (Y1) to formula (Y19) mentioned above are more preferable.


In formula (I-A2), nb4 is preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, and yet more preferably 2. When nb4 is 1 or 2, the bonding site of -Lb2-Yb1 is preferably the m-position of the benzene ring, with respect to the bonding site of SO3, as shown in the following structures:




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wherein, in the above formulas, Lb2, Yb1, Rb1 and nb3 are the same as defined in formula (I-A2).


In formula (I-A2), when nb4 is 2 or more, a plurality of Lb2 and Yb1 are preferably the same groups as each other.


Examples of the alkyl group having 1 to 6 carbon atoms as for Rb1 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group and a hexyl group. The number of carbon atoms of the alkyl group is preferably 1 to 4, and more preferably 1 to 3.


Examples of the halogen atom as for Rb1 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the group in which —CH2— included in the alkyl group is replaced by —O— or —CO— include a hydroxy group, a carboxy group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylcarbonyloxy group, an oxy group, a carbonyl group and the like. These specific examples are the same as those mentioned above.


Preferably, Rb1 is each independently a halogen atom or an alkyl group having 1 to 4 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), more preferably a fluorine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), and still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methoxy group or a methyl group.


nb3 is preferably an integer of 0 to 3, and more preferably an integer of 0 to 2. In one embodiment, nb3 is preferably 0. In another embodiment, nb3 is preferably 1 or 2. When nb3 is 1, Rb1 is preferably a halogen atom, and more preferably a fluorine atom or an iodine atom. When nb3 is 2, it is preferable that one of two Rb1 is a halogen atom, and the other one is a halogen atom or an alkyl group having 1 to 4 carbon atoms, and it is more preferable that one of Rb1 is a fluorine atom or an iodine atom, and the other one is a fluorine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms.


Examples of the anion (I-A2) include the following anions. Of these, anions represented by formula (I-a2-1) to formula (I-a2-20) are preferable, and anions represented by formula (I-a2-1) to formula (I-a2-11) and formula (I-a2-16) to formula (I-a2-20) are more preferable. The anions of the following formulas (I-a2-1) to (I-a2-20) may have a substituent not shown, with some Rb1 being omitted.




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Specific examples of the salt (I) include salts obtained by optionally combining the above-mentioned cations and anions. Specific examples of the salt (I) are shown in the following table.


In the following table, the respective symbols represent symbols attached to structures showing the above-mentioned anions and cations, and “to” indicates that each of the salt (I) and the anion (I) corresponds to each other. For example, the salt (I-1) indicates a salt composed of an anion represented by formula (I-a-1) and a cation represented by formula (I-c-1), the salt (1-2) indicates a salt composed of an anion represented by formula (I-a-2) and a cation represented by formula (I-c-1), and the salt (I-66) indicates a salt composed of an anion represented by formula (I-a-1) and a cation represented by formula (I-c-2).




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TABLE 1







Salt (I)
Anion (I)
Cation (I)









(I-1) to (I-65)
(I-a-1) to (I-a-65)
(I-c-1)



(I-66) to (I-130)
(I-a-1) to (I-a-65)
(I-c-2)



(I-131) to (I-195)
(I-a-1) to (I-a-65)
(I-c-3)



(I-196) to (I-260)
(I-a-1) to (I-a-65)
(I-c-4)



(I-261) to (I-325)
(I-a-1) to (I-a-65)
(I-c-5)



(I-326) to (I-390)
(I-a-1) to (I-a-65)
(I-c-6)



(I-391) to (I-455)
(I-a-1) to (I-a-65)
(I-c-7)



(I-456) to (I-520)
(I-a-1) to (I-a-65)
(I-c-8)



(I-521) to (I-585)
(I-a-1) to (I-a-65)
(I-c-9)



(I-586) to (I-650)
(I-a-1) to (I-a-65)
(I-c-10)



(I-651) to (I-715)
(I-a-1) to (I-a-65)
(I-c-11)



(I-716) to (I-780)
(I-a-1) to (I-a-65)
(I-c-12)



(I-781) to (I-845)
(I-a-1) to (I-a-65)
(I-c-13)



(I-846) to (I-910)
(I-a-1) to (I-a-65)
(I-c-14)



(I-911) to (I-975)
(I-a-1) to (I-a-65)
(I-c-15)



(I-976) to (I-1040)
(I-a-1) to (I-a-65)
(I-c-16)



(I-1041) to (I-1105)
(I-a-1) to (I-a-65)
(I-c-17)



(I-1106) to (I-1170)
(I-a-1) to (I-a-65)
(I-c-18)



(I-1171) to (I-1235)
(I-a-1) to (I-a-65)
(I-c-19)



(I-1236) to (I-1300)
(I-a-1) to (I-a-65)
(I-c-20)



(I-1301) to (I-1365)
(I-a-1) to (I-a-65)
(I-c-21)



(I-1366) to (I-1430)
(I-a-1) to (I-a-65)
(I-c-22)



(I-1431) to (I-1495)
(I-a-1) to (I-a-65)
(I-c-23)



(I-1496) to (I-1560)
(I-a-1) to (I-a-65)
(I-c-24)



(I-1561) to (I-1625)
(I-a-1) to (I-a-65)
(I-c-25)



(I-1626) to (I-1690)
(I-a-1) to (I-a-65)
(I-c-26)



(I-1691) to (I-1755)
(I-a-1) to (I-a-65)
(I-c-27)



(I-1756) to (I-1820)
(I-a-1) to (I-a-65)
(I-c-28)



(I-1821) to (I-1885)
(I-a-1) to (I-a-65)
(I-c-29)



(I-1886) to (I-1950)
(I-a-1) to (I-a-65)
(I-c-30)



(I-1951) to (I-2015)
(I-a-1) to (I-a-65)
(I-c-31)



(I-2016) to (I-2080)
(I-a-1) to (I-a-65)
(I-c-32)



(I-2081) to (I-2145)
(I-a-1) to (I-a-65)
(I-c-33)



(I-2146) to (I-2210)
(I-a-1) to (I-a-65)
(I-c-34)



(I-2211) to (I-2275)
(I-a-1) to (I-a-65)
(I-c-35)



(I-2276) to (I-2340)
(I-a-1) to (I-a-65)
(I-c-36)



(I-2341) to (I-2405)
(I-a-1) to (I-a-65)
(I-c-37)



(I-2406) to (I-2470)
(I-a-1) to (I-a-65)
(I-c-38)



(I-2471) to (I-2535)
(I-a-1) to (I-a-65)
(I-c-39)



(I-2536) to (I-2600)
(I-a-1) to (I-a-65)
(I-c-40)



(I-2601) to (I-2665)
(I-a-1) to (I-a-65)
(I-c-41)



(I-2666) to (I-2730)
(I-a-1) to (I-a-65)
(I-c-42)



(I-2731) to (I-2795)
(I-a-1) to (I-a-65)
(I-c-43)



(I-2796) to (I-2860)
(I-a-1) to (I-a-65)
(I-c-44)



(I-2861) to (I-2925)
(I-a-1) to (I-a-65)
(I-c-45)



(I-2926) to (I-2990)
(I-a-1) to (I-a-65)
(I-c-46)



(I-2991) to (I-3055)
(I-a-1) to (I-a-65)
(I-c-47)



(I-3056) to (I-3120)
(I-a-1) to (I-a-65)
(I-c-48)



(I-3121) to (I-3185)
(I-a-1) to (I-a-65)
(I-c-49)



(I-3186) to (I-3250)
(I-a-1) to (I-a-65)
(I-c-50)



(I-3251) to (I-3315)
(I-a-1) to (I-a-65)
(I-c-51)



(I-3316) to (I-3380)
(I-a-1) to (I-a-65)
(I-c-52)



(I-3381) to (I-3445)
(I-a-1) to (I-a-65)
(I-c-53)



(I-3446) to (I-3510)
(I-a-1) to (I-a-65)
(I-c-54)



(I-3511) to (I-3575)
(I-a-1) to (I-a-65)
(I-c-55)



(I-3576) to (I-3640)
(I-a-1) to (I-a-65)
(I-c-56)



(I-3641) to (I-3705)
(I-a-1) to (I-a-65)
(I-c-57)



(I-3706) to (I-3770)
(I-a-1) to (I-a-65)
(I-c-58)



(I-3771) to (I-3835)
(I-a-1) to (I-a-65)
(I-c-59)



(I-3836) to (I-3900)
(I-a-1) to (I-a-65)
(I-c-60)



(I-3901) to (I-3920)
(I-a2-1) to (I-a2-20)
(I-c-1)



(I-3921) to (I-3940)
(I-a2-1) to (I-a2-20)
(I-c-2)



(I-3941) to (I-3960)
(I-a2-1) to (I-a2-20)
(I-c-3)



(I-3961) to (I-3980)
(I-a2-1) to (I-a2-20)
(I-c-4)



(I-3981) to (I-4000)
(I-a2-1) to (I-a2-20)
(I-c-5)



(I-4001) to (I-4020)
(I-a2-1) to (I-a2-20)
(I-c-6)



(I-4021) to (I-4040)
(I-a2-1) to (I-a2-20)
(I-c-7)



(I-4041) to (I-4060)
(I-a2-1) to (I-a2-20)
(I-c-8)



(I-4061) to (I-4080)
(I-a2-1) to (I-a2-20)
(I-c-9)



(I-4081) to (I-4100)
(I-a2-1) to (I-a2-20)
(I-c-10)



(I-4101) to (I-4120)
(I-a2-1) to (I-a2-20)
(I-c-11)



(I-4121) to (I-4140)
(I-a2-1) to (I-a2-20)
(I-c-12)



(I-4141) to (I-4160)
(I-a2-1) to (I-a2-20)
(I-c-13)



(I-4161) to (I-4180)
(I-a2-1) to (I-a2-20)
(I-c-14)



(I-4181) to (I-4200)
(I-a2-1) to (I-a2-20)
(I-c-15)



(I-4201) to (I-4220)
(I-a2-1) to (I-a2-20)
(I-c-16)



(I-4221) to (I-4240)
(I-a2-1) to (I-a2-20)
(I-c-17)



(I-4241) to (I-4260)
(I-a2-1) to (I-a2-20)
(I-c-18)



(I-4261) to (I-4280)
(I-a2-1) to (I-a2-20)
(I-c-19)



(I-4281) to (I-4300)
(I-a2-1) to (I-a2-20)
(I-c-20)



(I-4301) to (I-4320)
(I-a2-1) to (I-a2-20)
(I-c-21)



(I-4321) to (I-4340)
(I-a2-1) to (I-a2-20)
(I-c-22)



(I-4341) to (I-4360)
(I-a2-1) to (I-a2-20)
(I-c-23)



(I-4361) to (I-4380)
(I-a2-1) to (I-a2-20)
(I-c-24)



(I-4381) to (I-4400)
(I-a2-1) to (I-a2-20)
(I-c-25)



(I-4401) to (I-4420)
(I-a2-1) to (I-a2-20)
(I-c-26)



(I-4421) to (I-4440)
(I-a2-1) to (I-a2-20)
(I-c-27)



(I-4441) to (I-4460)
(I-a2-1) to (I-a2-20)
(I-c-28)



(I-4461) to (I-4480)
(I-a2-1) to (I-a2-20)
(I-c-29)



(I-4481) to (I-4500)
(I-a2-1) to (I-a2-20)
(I-c-30)



(I-4501) to (I-4520)
(I-a2-1) to (I-a2-20)
(I-c-31)



(I-4521) to (I-4540)
(I-a2-1) to (I-a2-20)
(I-c-32)



(I-4541) to (I-4560)
(I-a2-1) to (I-a2-20)
(I-c-33)



(I-4561) to (I-4580)
(I-a2-1) to (I-a2-20)
(I-c-34)



(I-4581) to (I-4600)
(I-a2-1) to (I-a2-20)
(I-c-35)



(I-4601) to (I-4620)
(I-a2-1) to (I-a2-20)
(I-c-36)



(I-4621) to (I-4640)
(I-a2-1) to (I-a2-20)
(I-c-37)



(I-4641) to (I-4660)
(I-a2-1) to (I-a2-20)
(I-c-38)



(I-4661) to (I-4680)
(I-a2-1) to (I-a2-20)
(I-c-39)



(I-4681) to (I-4700)
(I-a2-1) to (I-a2-20)
(I-c-40)



(I-4701) to (I-4720)
(I-a2-1) to (I-a2-20)
(I-c-41)



(I-4721) to (I-4740)
(I-a2-1) to (I-a2-20)
(I-c-42)



(I-4741) to (I-4760)
(I-a2-1) to (I-a2-20)
(I-c-43)



(I-4761) to (I-4780)
(I-a2-1) to (I-a2-20)
(I-c-44)



(I-4781) to (I-4800)
(I-a2-1) to (I-a2-20)
(I-c-45)



(I-4801) to (I-4820)
(I-a2-1) to (I-a2-20)
(I-c-46)



(I-4821) to (I-4840)
(I-a2-1) to (I-a2-20)
(I-c-47)



(I-4841) to (I-4860)
(I-a2-1) to (I-a2-20)
(I-c-48)



(I-4861) to (I-4880)
(I-a2-1) to (I-a2-20)
(I-c-49)



(I-4881) to (I-4900)
(I-a2-1) to (I-a2-20)
(I-c-50)



(I-4901) to (I-4920)
(I-a2-1) to (I-a2-20)
(I-c-51)



(I-4921) to (I-4940)
(I-a2-1) to (I-a2-20)
(I-c-52)



(I-4941) to (I-4960)
(I-a2-1) to (I-a2-20)
(I-c-53)



(I-4961) to (I-4980)
(I-a2-1) to (I-a2-20)
(I-c-54)



(I-4981) to (I-5000)
(I-a2-1) to (I-a2-20)
(I-c-55)



(I-5001) to (I-5020)
(I-a2-1) to (I-a2-20)
(I-c-56)



(I-5021) to (I-5040)
(I-a2-1) to (I-a2-20)
(I-c-57)



(I-5041) to (I-5060)
(I-a2-1) to (I-a2-20)
(I-c-58)



(I-5061) to (I-5080)
(I-a2-1) to (I-a2-20)
(I-c-59)



(I-5081) to (I-5100)
(I-a2-1) to (I-a2-20)
(I-c-60)



(I-5101) to (I-5165)
(I-a-1) to (I-a-65)
(I-c-61)



(I-5166) to (I-5230)
(I-a-1) to (I-a-65)
(I-c-62)



(I-5231) to (I-5295)
(I-a-1) to (I-a-65)
(I-c-63)



(I-5296) to (I-5360)
(I-a-1) to (I-a-65)
(I-c-64)



(I-5361) to (I-5425)
(I-a-1) to (I-a-65)
(I-c-65)



(I-5426) to (I-5490)
(I-a-1) to (I-a-65)
(I-c-66)



(I-5491) to (I-5555)
(I-a-1) to (I-a-65)
(I-c-67)



(I-5556) to (I-5620)
(I-a-1) to (I-a-65)
(I-c-68)



(I-5621) to (I-5685)
(I-a-1) to (I-a-65)
(I-c-69)



(I-5686) to (I-5750)
(I-a-1) to (I-a-65)
(I-c-70)



(I-5751) to (I-5770)
(I-a2-1) to (I-a2-20)
(I-c-61)



(I-5771) to (I-5790)
(I-a2-1) to (I-a2-20)
(I-c-62)



(I-5791) to (I-5810)
(I-a2-1) to (I-a2-20)
(I-c-63)



(I-5811) to (I-5830)
(I-a2-1) to (I-a2-20)
(I-c-64)



(I-5831) to (I-5850)
(I-a2-1) to (I-a2-20)
(I-c-65)



(I-5851) to (I-5870)
(I-a2-1) to (I-a2-20)
(I-c-66)



(I-5871) to (I-5890)
(I-a2-1) to (I-a2-20)
(I-c-67)



(I-5891) to (I-5910)
(I-a2-1) to (I-a2-20)
(I-c-68)



(I-5911) to (I-5930)
(I-a2-1) to (I-a2-20)
(I-c-69)



(I-5931) to (I-5950)
(I-a2-1) to (I-a2-20)
(I-c-70)



(I-5951) to (I-6015)
(I-a-1) to (I-a-65)
(I-c-71)



(I-6016) to (I-6080)
(I-a-1) to (I-a-65)
(I-c-72)



(I-6081) to (I-6145)
(I-a-1) to (I-a-65)
(I-c-73)



(I-6146) to (I-6210)
(I-a-1) to (I-a-65)
(I-c-74)



(I-6211) to (I-6275)
(I-a-1) to (I-a-65)
(I-c-75)



(I-6276) to (I-6340)
(I-a-1) to (I-a-65)
(I-c-76)



(I-6341) to (I-6405)
(I-a-1) to (I-a-65)
(I-c-77)



(I-6406) to (I-6470)
(I-a-1) to (I-a-65)
(I-c-78)



(I-6471) to (I-6535)
(I-a-1) to (I-a-65)
(I-c-79)



(I-6536) to (I-6600)
(I-a-1) to (I-a-65)
(I-c-80)



(I-6601) to (I-6620)
(I-a2-1) to (I-a2-20)
(I-c-71)



(I-6621) to (I-6640)
(I-a2-1) to (I-a2-20)
(I-c-72)



(I-6641) to (I-6660)
(I-a2-1) to (I-a2-20)
(I-c-73)



(I-6661) to (I-6680)
(I-a2-1) to (I-a2-20)
(I-c-74)



(I-6681) to (I-6700)
(I-a2-1) to (I-a2-20)
(I-c-75)



(I-6701) to (I-6720)
(I-a2-1) to (I-a2-20)
(I-c-76)



(I-6721) to (I-6740)
(I-a2-1) to (I-a2-20)
(I-c-77)



(I-6741) to (I-6760)
(I-a2-1) to (I-a2-20)
(I-c-78)



(I-6761) to (I-6780)
(I-a2-1) to (I-a2-20)
(I-c-79)



(I-6781) to (I-6800)
(I-a2-1) to (I-a2-20)
(I-c-80)



(I-6801) to (I-6880)
(I-a-66)
(I-c-1) to (I-c-80)



(I-6881) to (I-6960)
(I-a-67)
(I-c-1) to (I-c-80)



(I-6961) to (I-7040)
(I-a-68)
(I-c-1) to (I-c-80)



(I-7041) to (I-7120)
(I-a-69)
(I-c-1) to (I-c-80)



(I-7121) to (I-7200)
(I-a-70)
(I-c-1) to (I-c-80)










Of these, the salt (I) is preferably a salt obtained by combining an anion represented by any one of formula (I-a-1) to formula (I-a-4), formula (I-a-7) to formula (I-a-11), formula (I-a-14) to formula (I-a-30) and formula (I-a-35) to formula (I-a-70), and formula (I-a2-1) to formula (I-a2-11) and formula (I-a2-16) to formula (I-B-20) with a cation represented by any one of formula (I-c-1) to formula (I-c-80).


<Method for Producing Salt (I)>

The salt (I) can be produced by reacting a salt represented by formula (I-a) with a salt represented by formula (I-b) in a solvent:




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wherein all symbols are the same as defined above, RA, RB and RC each independently represent a hydrocarbon group having 1 to 12 carbon atoms, or RA, RB and RC may be bonded to each other to form an aromatic ring, and RD represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.


Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, water and the like.


The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.


Examples of the salt represented by formula (I-b) include salts represented by the following formulas. These salts can be easily produced by the methods mentioned in JP 2011-116747 A and JP 2016-047815 A, or a known production method.




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The salt represented by formula (I-a) can be produced by passing the salt represented by formula (I-a′) through an ion-exchange resin:




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wherein all symbols are the same as defined above, respectively.


Examples of the ion-exchange resin include an ion-exchange resin (No. 6, 100-200 mesh, manufactured by Wako Pure Chemical Industries, Ltd.) and the like.


Examples of the solvent include methanol and the like.


When X is a sulfur atom, the salt represented by formula (I-a′) can be produced by reacting a compound represented by formula (I-c) with a compound represented by formula (I-d) in the presence of trifluoroacetic anhydride and trifluoromethanesulfonic acid in a solvent:




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wherein all symbols are the same as defined above, respectively.


Examples of the solvent include chloroform, monochlorobenzene, acetonitrile and the like.


The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 to 24 hours.


Examples of the compound represented by formula (I-c) include compounds represented by the following formulas, which are easily available on the market.




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Examples of the compound represented by formula (I-d) include compounds represented by the following formulas, which are easily available on the market.




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When X is an iodine atom, the salt represented by formula (I-a) can be produced by reacting a compound represented by formula (I-f) with a compound represented by formula (I-d) in the presence of potassium peroxymonosulfate and sulfuric acid in a solvent, followed by a treatment with hydrochloric acid:




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wherein all symbols are the same as defined above, respectively.


Examples of the solvent include chloroform, monochlorobenzene, acetonitrile and the like.


The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 to 24 hours.


Examples of the compound represented by formula (I-f) include compounds represented by the following formulas, which are easily available on the market.




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<Acid Generator>

The acid generator of the present invention is an acid generator including a salt (I) of the present invention. The acid generator may include one salt (I), or may include two or more salts (I).


The acid generator of the present invention may include, in addition to the salt (I), a known compound acting as an acid generator in the resist field (hereinafter sometimes referred to as “compound (B)” or “acid generator (B)”). The compound (B) may be used alone, or two or more thereof may be used in combination.


<Compound (B)>

Either nonionic compound or ionic compound may be used as the compound (B). Examples of the nonionic compound include sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (e.g., disulfone, ketosulfone, sulfonyldiazomethane) and the like. Typical examples of the ionic compound include onium salts containing an onium cation (e.g., diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the anion of the onium salt include a sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion or a carboxylic acid anion.


The compound (B) may be one of the structural units constituting the resin contained in the resist composition of the present invention, like the structural unit (a7) described below.


Specific examples of the compound (B) include compounds generating an acid upon exposure to radiation mentioned in JP 63-26653 A, JP 55-164824 A, JP 62-69263 A, JP 63-146038 A, JP 63-163452 A, JP 62-153853 A, JP 63-146029 A, U.S. Pat. Nos. 3,779,778, 3,849,137, DE Patent No. 3914407, EP Patent No. 126,712 and the like. Compounds produced by a known method may also be used. Two or more compounds (B) may also be used in combination.


The compound (B) is preferably a salt represented by formula (B1) (hereinafter sometimes referred to as “compound (B1)” or “salt (B1)”, in which the salt (I) is excluded), and more preferably a salt represented by formula (B1-1) (hereinafter sometimes referred to as “compound (B1-1)” or “salt (B1-1)”, in which the salt (I) is excluded) or a salt represented by formula (B1-2) (hereinafter sometimes referred to as “compound (B1-2)” or “salt (B1-2)”, in which the salt (I) is excluded):




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wherein, in formula (B1), symbols Lb1, Lb2, Yb1 and nb1 are the same as defined in formula (I), and

    • Z1+ represents an organic cation, in which a cation represented by formula (I-C) is excluded:




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wherein, in formula (B1-1), Qb1, Qb2, Qb3, Qb4, z1, X1, Lb3, Lb2, Yb1 and nb2 are the same as defined in formula (I-A1), and

    • Z2+ represents an organic cation, in which a cation represented by formula (I-C) is excluded, and:




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wherein, in formula (B1-2), Lb2, Yb1, Rb1, nb4 and nb3 are the same as defined in formula (I-A2), and

    • Z3+ represents an organic cation, in which a cation represented by formula (I-C) is excluded.


Examples of Lb1, Lb2, Yb1 and nb1 in formula (B1) include those which are the same as Lb1, Lb2, Yb1 and nb1 mentioned above in formula (I), respectively.


Examples of Qb1, Qb2, Qb3, Qb4, z1, X1, Lb3, Lb2, ybi and nb2 in formula (B1-1) include those which are the same as Qb1, Qb2, Qb3, Qb4, z1, X1, Lb3, Lb2, Yb1 and nb2 mentioned above in formula (I-A1), respectively.


Examples of the sulfonic acid anion in formula (B1-1) include those which are the same as the anion represented by formula (I-A1).


Examples of Lb2, Yb1, Rb1, nb4 and nb3 in formula (B1-2) include those which are the same as Lb2, Yb1, Rb1, nb4 and nb3 mentioned above in formula (I-A2), respectively.


Examples of the sulfonic acid anion in formula (B1-2) include those which are the same as the anion represented by formula (I-A2).


In another embodiment of the compound (B), it is also possible to preferably use, as the compound (B), a salt in which the sulfonic acid anion in the salt represented by formula (B1) is replaced by a sulfonylimide anion, a sulfonylmethide anion or a carboxylic acid anion.


Examples of the sulfonylimide anion or sulfonylmethide anion include an anion represented by the following formula (B1-A3) (hereinafter sometimes referred to as “anion (B1-A3)”):




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wherein, in formula (B1-A3),

    • A1 represents a nitrogen atom or a carbon atom,
    • Lb2′ represents a single bond or a divalent hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—,
    • Yb1′ represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —SO2— or —CO—, and two —SO2-Lb2′-Yb1′ may be bonded to each other to form a ring containing A1, and
    • nb5 represents 2 or 3, and when nb5 is 2, A1 represents a nitrogen atom, and when nb5 is 3, A1 represents a carbon atom, and a plurality of groups in parentheses may be the same or different from each other.


In formula (B1-A3), examples of the hydrocarbon group, the cyclic hydrocarbon group and the substituent as for Lb2, and Yb1′ include the same groups as Lb2 and Yb1 of formula (B1-A1).


In formula (B1-A3), Lb2′ is preferably a single bond, *-Lb23-, *-Lb23-X2— or *-Lb23-X2—W2—X3— (Lb23 represents a chain hydrocarbon group having 1 to 6 carbon atoms which may have a fluorine atom, X2 and X3 each independently represent —O—, —CO—O—, —O—CO—, —O—CO—O— or —O—, W2 represents an alicyclic hydrocarbon group having 3 to 12 carbon atoms, —CH2— included in the alicyclic hydrocarbon group may be replaced by —O— or —CO—, and * represents a bonding site to SO2).


In formula (B1-A3), Yb1′ is preferably a methyl group having a fluorine atom or a cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent (—CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—), and more preferably a trifluoromethyl group, an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (—CH2— included in the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—) or an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent. Specifically, a trifluoromethyl group or groups represented by formula (Y1) to formula (Y36) exemplified in formula (I-A1) is/are preferable.


In formula (B1-A3), when two —SO2-Lb2′-Yb1′ combine to form a ring containing A1, examples include an anion represented by formula (B1-A3′):




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wherein, in formula (B1-A3′),

    • A1, Yb1′, Lb2′ and nb5 are the same as defined in formula (B1-A3), and
    • Wb4 represents a disulfonylimide ring or disulfonylmethide ring having 2 to 12 carbon atoms which may have a fluorine atom.


The disulfonylimide ring or disulfonylmethide ring as for Wb4 preferably has 3 to 12 carbon atoms, and more preferably 3 to 6 carbon atoms, and the hydrogen atom of the methylene group included in the ring is preferably substituted with a fluorine atom.


Examples of the anion represented by formula (B1-A3) include the following. Of these, an anion represented by formula (B1-a3-1) or formula (B1-a3-2) is preferable.




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Examples of the carboxylic acid anion include the following.




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Examples of the organic cation as for Z1+, Z2+ and Z3+ include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation and an organic phosphonium cation. Of these, an organic sulfonium cation and an organic iodonium cation are preferable, and an arylsulfonium cation is more preferable. Specific examples thereof include a cation represented by any one of formula (b2-1) to formula (b2-5) (hereinafter sometimes referred to as “cation (b2-1)” or the like according to the number of formula):




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wherein, in formula (b2-1) to formula (b2-5),

    • Rb4 to Rb6 each independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms or an aromatic hydrocarbon group having 6 to 36 carbon atoms, a hydrogen atom included in the chain hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom included in the alicyclic hydrocarbon group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group, and a hydrogen atom included in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkyl fluoride group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms,
    • Rb4 and Rb5 may be bonded to each other to form a ring together with sulfur atoms to which Rb4 and Rb5 are bonded, and —CH2— included in the ring may be replaced by —O—, —S— or —CO—,
    • Rb7 and Rb8 each independently represent a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkyl fluoride group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms,
    • m2 and n2 each independently represent an integer of 0 to 5,
    • when m2 is 2 or more, a plurality of Rb7 may be the same or different, and when n2 is 2 or more, a plurality of Rb8 may be the same or different,
    • Rb9 and Rb10 each independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms,
    • Rb9 and Rb10 may be bonded to each other to form a ring together with sulfur atoms to which Rb9 and Rb10 are bonded, and —CH2— included in the ring may be replaced by —O—, —S— or —CO—,
    • Rb11 represents a hydrogen atom, a chain hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms,
    • Rb12 represents a chain hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom included in the chain hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom included in the aromatic hydrocarbon group may be substituted with an alkoxy group having 1 to 12 carbon atoms or an alkylcarbonyloxy group having 1 to 12 carbon atoms,
    • Rb11 and R12 may be bonded to each other to form a ring, including —CH—CO— to which Rb11 and Rb12 are bonded, and —CH2— included in the ring may be replaced by —O—, —S— or —CO—,
    • Rb13 to Rb18 and Rb21 to Rb26 each independently represent a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkyl fluoride group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms,
    • Rb13 and Rb14, and Rb21 and Rb22 may be bonded to each other to form a ring having a sulfur atom together with the benzene ring to which Rb13 and Rb14 are bonded, and —CH2— included in the ring may be replaced by —O—, —S— or —CO—,
    • Rb27 to Rb29 each independently represent a hydrogen atom or a group having an acid-labile group,
    • Lb31 and Lb41 to Lb43 each independently represent a sulfur atom or an oxygen atom,
    • o2, p2, s2 and t2 each independently represent an integer of 0 to 5,
    • q2 and r2 each independently represent an integer of 0 to 4,
    • u2 represents 0 or 1, and
    • when o2 is 2 or more, a plurality of Rb13 are the same or different, when p2 is 2 or more, a plurality of Rb14 are the same or different, when q2 is 2 or more, a plurality of Rb15 are the same or different, when r2 is 2 or more, a plurality of Rb16 are the same or different, when s2 is 2 or more, a plurality of Rb17 are the same or different, and when t2 is 2 or more, a plurality of Rb18 are the same or different,
    • u3 represents an integer of 1 to 3, and satisfies 1≤u3+q23≤5,
    • u4 and u5 each independently represent an integer of 0 to 3, and satisfy 0≤u4+o21≤5 and 0≤u5+p22≤5,
    • when u3, u4 and u5 are each 2 or more, a plurality of groups in parentheses are each the same or different,
    • o21, p22, q23, r24, t25 and s26 each independently represent an integer of 0 to 4, and
    • when o21, p22, q23, r24, t25 and s26 are each 2 or more, a plurality of Rb21 to Rb26 are each the same or different.


When u2 is 0, any one of o2, p2, q2 and r2 is preferably 1 or more and at least one of Rb13 to Rb16 is preferably a halogen atom, and when u2 is 1, any one of o2, p2, s2, t2, q2 and r2 is preferably 1 or more and at least one of Rb13 to Rb18 is preferably a halogen atom.


Further, when u2 is 0, r2 is preferably 1 or more, and more preferably 1. When u2 is 0 and r2 is 1 or more, Rb16 is preferably a halogen atom.


The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.


Examples of the chain hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group.


Particularly, the chain hydrocarbon group of Rb9 to Rb12 preferably has 1 to 12 carbon atoms.


The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.




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Particularly, the alicyclic hydrocarbon group of Rb9 to Rb12 preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.


Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, a 2-ethyladamantan-2-yl group, a 2-isopropyladamantan-2-yl group, a methylnorbornyl group, an isobornyl group and the like. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.


The alkyl fluoride group represents an alkyl group having 1 to 12 carbon atoms which has a fluorine atom, and examples thereof include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a perfluorobutyl and the like. The number of carbon atoms of the alkyl fluoride group is preferably 1 to 9, more preferably 1 to 6, still more preferably 1 to 4.


Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a biphenyl group, a naphthyl group and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples thereof include aromatic hydrocarbon groups which have a chain hydrocarbon group having 1 to 18 carbon atoms (a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, etc.) and aromatic hydrocarbon groups which have an alicyclic hydrocarbon group having 3 to 18 carbon atoms (a p-cyclohexylphenyl group, a p-adamantylphenyl group, etc.) and the like. When the aromatic hydrocarbon group has a chain hydrocarbon group or an alicyclic hydrocarbon group, a chain hydrocarbon group having 1 to 18 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms are preferable.


Examples of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group and the like.


Examples of the chain hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group and a naphthylethyl group.


Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.


Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.


The ring formed by bonding Rb4 and Rb5 each other, together with sulfur atoms to which Rb4 and Rb5 are bonded, may be a monocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturated ring. This ring includes a ring having 3 to 18 carbon atoms and is preferably a ring having 4 to 18 carbon atoms. The ring having a sulfur atom includes a 3-membered to 12-membered ring and is preferably a 3-membered to 7-membered ring and includes, for example, the following rings and the like. * represents a bonding site.




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The ring formed by combining Rb9 and Rb10 together may be a monocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturated ring. This ring includes a 3-membered to 12-membered ring and is preferably a 3-membered to 7-membered ring. The ring includes, for example, a thiolan-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxathian-4-ium ring and the like.


The ring formed by combining Rb11 and Rb12 together may be a monocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturated ring. This ring includes a 3-membered to 12-membered ring and is preferably a 3-membered to 7-membered ring. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, an oxoadamantane ring and the like.


Examples of the group having an acid-labile group as for Rb27 to Rb29 include a group represented by —Rc30, —CO—O—Rc30 or -Lc10-CO—O—Rc30 (Lc10 represents an alkanediyl group having 1 to 6 carbon atoms, and Rc30 represents an acid-labile group) and the like.


Examples of the acid-labile group as for Rb27 to Rb21 include groups represented by formula (1) or formula (2) mentioned above.


Of cation (b2-1) to cation (b2-5), a cation (b2-1) is preferable.


Examples of the cation (b2-1) include the following cations.




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Examples of the cation (b2-2) include the following cations.




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Examples of the cation (b2-3) include the following cations.




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Examples of the cation (b2-4) include the following cations.




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Examples of the cation (b2-5) include the following cations.




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The compound (B) is a combination of the anion mentioned above and the organic cation mentioned above, and these can be optionally combined. Examples of the acid generator (B) preferably include a combination of an anion represented by any one of formula (I-a-1) to formula (I-a-4), formula (I-a-7) to formula (I-a-11), formula (I-a-14) to formula (I-a-30) and formula (I-a-35) to formula (I-a-70), or an anion represented by any one of formula (I-a2-1) to formula (I-a2-11) and formula (I-a2-16) to formula (I-a2-20), or an anion represented by any one of formula (B1-a3-1) to formula (B1-a3-20) with a cation (b2-1), a cation (b2-2), a cation (b2-3), a cation (b2-4) or a cation (b2-5).


Examples of the compound (B) preferably include those represented by formula (B1-1) to formula (B1-105), formula (B2-1) to formula (B2-20) and formula (B3-1) to formula (B3-28). Of these, those containing an arylsulfonium cation are preferable, and those represented by formula (B1-1) to formula (B1-3), formula (B1-5) to formula (B1-7), formula (B1-11) to formula (B1-14), formula (B1-20) to formula (B1-26), formula (B1-29) and formula (B1-31) to formula (B1-105), formula (B2-1) to formula (B2-20) and formula (B3-1) to formula (B3-28) are particularly preferable.




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When the salt (I) and the compound (B) are included as the acid generator, a ratio of the content of the salt (I) to that of the compound (B) (mass ratio; salt (I):compound (B)) is usually 1:99 to 99:1, preferably 2:98 to 98:2, more preferably 5:95 to 95:5, still more preferably 10:90 to 90:10, and particularly preferably 15:85 to 85:15.


<Resist Composition>

The resist composition of the present invention includes an acid generator containing a salt (I) of the present invention. The resist composition of the present invention may further include a resin. Examples of the resin include a resin including a structural unit having an acid-labile group (hereinafter sometimes referred to as “resin (A)”) and/or resins other than the resin (A). The “acid-labile group” means a group having a leaving group which is eliminated by contact with an acid, thus converting a constitutional unit into a constitutional unit having a hydrophilic group (e.g. a hydroxy group or a carboxy group).


The resist composition of the present invention preferably includes a quencher such as a salt generating an acid having an acidity lower than that of an acid generated from the acid generator (hereinafter sometimes referred to as “quencher (C)”), and preferably includes a solvent (hereinafter sometimes referred to as “solvent (E)”).


<Acid Generator>

In the resist composition of the present invention, the total content of the acid generator is preferably 0.1% by mass or more and 99.9% by mass or less, more preferably 1% by mass or more and 45% by mass or less, still more preferably 1% by mass or more and 40% by mass or less, and yet more preferably 3% by mass or more and 40% by mass or less, based on the solid content of the resist composition. When including the below-mentioned resin (A), the total content of the acid generator is preferably 1 part by mass or more and 45 parts by mass or less, more preferably 1 part by mass or more and 40 parts by mass or less, and still more preferably 3 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of the below-mentioned resin (A).


<Resin (A)>

The resin (A) includes a structural unit having an acid-labile group (hereinafter sometimes referred to as “structural unit (a1)”). It is preferable that the resin (A) further includes a structural unit other than the structural unit (a1). Examples of the structural unit other than the structural unit (a1) include a structural unit having no acid-labile group (hereinafter sometimes referred to as “structural unit (s)”), a structural unit other than the structural unit (a1) and the structural unit (s) (e.g. a structural unit having a halogen atom mentioned later (hereinafter sometimes referred to as “structural unit (a4)”)), a structural unit having a non-leaving hydrocarbon group mentioned later (hereinafter sometimes referred to as “structural unit (a5)”) and other structural units derived from monomers known in the art.


<Structural Unit (a1)>


The structural unit (a1) is derived from a monomer having an acid-labile group (hereinafter sometimes referred to as “monomer (a1)”).


The acid-labile group contained in the resin (A) is preferably a group represented by formula (1) (hereinafter also referred to as group (1)) and/or a group represented by formula (2) (hereinafter also referred to as group (2)):




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wherein, in formula (1), Ra1, Ra2 and Ra3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups obtained by combining these groups, or Ra1 and Ra2 are bonded to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with carbon atoms to which Ra1 and Ra2 are bonded, and the alkyl group, the alkenyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a halogen atom,

    • ma and na each independently represent 0 or 1, and at least one of ma and na represents 1, and
    • * represents a bonding site:




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wherein, in formula (2), Ra1′ and Ra2′ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, Ra3′ represents a hydrocarbon group having 1 to 20 carbon atoms, or Ra2′ and Ra3′ are bonded to each other to form a heterocyclic ring group having 3 to 20 carbon atoms together with carbon atoms and X to which Ra2′ and Ra3′ are bonded, —CH2— included in the hydrocarbon group and the heterocyclic ring group may be replaced by —O— or —S—, and the hydrocarbon group and the heterocyclic ring group may have a halogen atom,

    • X represents an oxygen atom or a sulfur atom,
    • na′ represents 0 or 1, and
    • * represents a bonding site.


Examples of the alkyl group in Ra1, Ra2 and Ra3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like.


Examples of the alkenyl group in Ra1, Ra2 and Ra3 include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, an isooctenyl group and a nonenyl group.


The alicyclic hydrocarbon group in Ra1, Ra2 and Ra3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* represents a bonding site). The number of carbon atoms of the alicyclic hydrocarbon group of Ra1, Ra2 and Ra3 is preferably 3 to 16.




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Examples of the aromatic hydrocarbon group in Ra1, Ra2 and Ra3 include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.


Examples of the combined group include groups obtained by combining the above-mentioned alkyl group and alicyclic hydrocarbon group (e.g., alkylcycloalkyl groups or cycloalkylalkyl groups, such as a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group and a norbornylethyl group), aralkyl groups such as a benzyl group, aromatic hydrocarbon groups having an alkyl group (a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups having an alicyclic hydrocarbon group (a p-cyclohexylphenyl group, a p-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as a phenylcyclohexyl group, and the like.


Preferably, ma is 0 and na is 1.


When Ra1 and Ra2 are bonded to each other to form an alicyclic hydrocarbon group, examples of —C(Ra1)(Ra2)(Ra3) include the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * represents a bonding site to —O—.




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Examples of the hydrocarbon group in Ra1′, Ra2′ and Ra3′ include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups formed by combining these groups.


Examples of the alkyl group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and the groups obtained by combining these groups include those which are the same as mentioned as for Ra1, Ra2 and Ra3.


When Ra2′ and Ra3′ are bonded to each other to form a heterocyclic group together with carbon atoms and X to which Ra2′ and Ra3′ are bonded, examples of —C(Ra1′)(Ra2′)—X—Ra3′ include the following groups. * represents a bonding site.




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Examples of the halogen atom which may be possessed by Ra1, Ra2, Ra3, Ra1′, Ra2′ and Ra3′ include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.


At least one of Ra1′ and Ra2′ is preferably a hydrogen atom.


na′ is preferably 0.


Examples of the group (1) include the following groups.


A group wherein, in formula (1), Ra1, Ra2 and Ra3 are alkyl groups, ma=0 and na=1. The group is preferably a tert-butoxycarbonyl group.


A group wherein, in formula (1), Ra1 and Ra2 are bonded to each other to form an adamantyl group together with carbon atoms to which Ra1 and Ra2 are bonded, Ra3 is an alkyl group, ma=0 and na=1.


A group wherein, in formula (1), Ra1 and Ra2 are each independently an alkyl group, Ra3 is an adamantyl group, ma=0 and na=1.


Specific examples of the group (1) include the following groups. * represents a bonding site.




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Specific examples of the group (2) include the following groups. * represents a bonding site.




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The monomer (a1) is preferably a monomer having an acid-labile group and an ethylenic unsaturated bond, and more preferably a (meth)acrylic monomer having an acid-labile group.


Of the (meth)acrylic monomers having an acid-labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferably exemplified. When a resin (A) including a structural unit derived from a monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in a resist composition, it is possible to improve the resolution of a resist pattern.


The structural unit derived from a (meth)acrylic monomer having a group (1) includes a structural unit represented by formula (a1-0) (hereinafter sometimes referred to as structural unit (a1-0)), a structural unit represented by formula (a1-1) (hereinafter sometimes referred to as structural unit (a1-1)) or a structural unit represented by formula (a1-2) (hereinafter sometimes referred to as structural unit (a1-2)). Preferably, the structural unit is at least one structural unit selected from the group consisting of a structural unit (a1-0), a structural unit (a1-1) and a structural unit (a1-2), and more preferably at least one or two structural units selected from the group consisting of a structural unit (a1-1) and a structural unit (a1-2). These structural units may be used alone, or two or more structural units may be used in combination.




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wherein, in formula (a1-0), formula (a1-1) and formula (a1-2),

    • La01, La1 and La2 each independently represent —O— or *—O—(CH2)k1—CO—O—, k1 represents an integer of 1 to 7, and * represents a bonding site to —CO—,
    • Ra01, Ra4 and Ra5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra02, Ra03 and Ra04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups obtained by combining these groups, and the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a halogen atom,
    • Ra6 and Ra7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups obtained by combining these groups,
    • m1′ represents an integer of 0 to 14,
    • n1 represents an integer of 0 to 10, and
    • n1′ represents an integer of 0 to 3.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.


Examples of the alkyl group as for Ra01, Ra4 and Ra5 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group.


Ra01, Ra4 and Ra5 are preferably a hydrogen atom or a methyl group, and more preferably a methyl group.


La01, La1 and La2 are preferably an oxygen atom or *—O—(CH2)k01—CO—O— (in which k01 is preferably an integer of 1 to 4, and more preferably 1), and more preferably an oxygen atom.


Examples of the alkyl group, the alkenyl group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and groups obtained by combining these groups in Ra02, Ra03, Ra04, Ra6 and Ra7 include the same groups as mentioned as for Ra1, Ra2 and Ra3 of formula (1).


The alkyl group in Ra02, Ra03 and Ra04 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.


The alkyl group in Ra6 and Ra7 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group or a t-butyl group, and still more preferably an ethyl group, an isopropyl group or a t-butyl group.


The alkenyl group in Ra6 and Ra7 is preferably an alkenyl group having 2 to 6 carbon atoms, and more preferably an ethenyl group, a propenyl group, an isopropenyl group or a butenyl group.


The number of carbon atoms of the alicyclic hydrocarbon group as for Ra02, Ra03, Ra04, Ra6 and Ra7 is preferably 5 to 12, and more preferably 5 to 10.


The number of carbon atoms of the aromatic hydrocarbon group of Ra02, Ra03, Ra04, Ra6 and Ra7 is preferably 6 to 12, and more preferably 6 to 10.


The total number of carbon atoms of the groups obtained by combining the alkyl group with the alicyclic hydrocarbon group is preferably 18 or less.


The total number of carbon atoms of the groups obtained by combining the alkyl group with the aromatic hydrocarbon group is preferably 18 or less.


Ra02 and Ra03 are preferably an alkyl group having 1 to 6 carbon atoms which may have a halogen atom or an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a halogen atom, and more preferably a methyl group, an ethyl group, a phenyl group or a naphthyl group which may have a halogen atom.


Ra04 is preferably an alkyl group having 1 to 6 carbon atoms which may have a halogen atom or an alicyclic hydrocarbon group having 5 to 12 carbon atoms which may have a halogen atom, and more preferably a methyl group, an ethyl group, a cyclohexyl group or a adamantyl group which may have a halogen atom.


Ra6 and Ra7 are preferably an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group, a phenyl group or a naphthyl group, and still more preferably an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group or a phenyl group.


m1′ is preferably an integer of 0 to 3, and more preferably 0 or 1.


n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.


n1′ is preferably 0 or 1.


The structural unit (a1-0) includes, for example, a structural unit represented by any one of formula (a1-0-1) to formula (a1-0-18) and a structural unit in which a methyl group corresponding to Ra01 in the structural unit (a1-0) is substituted with a hydrogen atom, a halogen atom, a haloalkyl group (an alkyl group having a halogen atom) or other alkyl groups, and is preferably a structural unit represented by any one of formula (a1-0-1) to formula (a1-0-10), formula (a1-0-13) and formula (a1-0-14).




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The structural unit (a1-1) includes, for example, structural units derived from the monomers mentioned in JP 2010-204646 A. Of these structural units, a structural unit represented by any one of formula (a1-1-1) to formula (a1-1-7) and a structural unit in which a methyl group corresponding to Ra4 in the structural unit (a1-1) is substituted with a hydrogen atom, a halogen atom, a haloalkyl group or other alkyl groups are preferable, and a structural unit represented by any one of formula (a1-1-1) to formula (a1-1-4) is more preferable.




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Examples of the structural unit (a1-2) include a structural unit represented by any one of formula (a1-2-1) to formula (a1-2-14), and a structural unit in which a methyl group corresponding to Ra5 in the structural unit (a1-2) is substituted with a hydrogen atom, a halogen atom, a haloalkyl group or other alkyl groups, and a structure unit represented by any one of formula (a1-2-2), formula (a1-2-5), formula (a1-2-6) and formula (a1-2-10) to formula (a1-2-14) is preferable.




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When the resin (A) includes a structural unit (a1-0) and/or a structural unit (a1-1) and/or a structural unit (a1-2), the total content of them is usually 10 mol % or more, preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 25 mol % or more, yet more preferably 30 mol % or more, further preferably 40 mol % or more, and still further preferably 50 mol % or more, based on all structural units of the resin (A). The total content is also usually 95 mol % or less, preferably 90 mol % or less, more preferably 85 mol % or less, still more preferably 70 mol % or less, and yet more preferably 65 mol % or less, based on all structural units of the resin (A). Specifically, the total content is usually 10 to 95 mol %, preferably 15 to 90 mol %, more preferably 20 to 85 mol %, still more preferably 25 to 70 mol %, and yet more preferably 30 to 70 mol %, based on all structural units of the resin (A).


When the resin (A) includes a structural unit (a1-0), the content is usually 5 mol % or more, preferably 10 mol % or more, more preferably 15 mol % or more, still more preferably 20 mol % or more, yet more preferably 25 mol % or more, further preferably 30 mol % or more, and still further preferably 35 mol % or more, based on all structural units of the resin (A). The content is also usually 80 mol % or less, preferably 75 mol % or less, more preferably 70 mol % or less, still more preferably 65 mol % or less, and yet more preferably 60 mol % or less, based on all structural units of the resin (A). Specifically, the content is usually 5 to 80 mol %, preferably 5 to 75 mol %, and more preferably 10 to 70 mol %, based on all structural units of the resin (A).


When the resin (A) includes a structural unit (a1-1) and/or a structural unit (a1-2), the total content of them is usually 10 mol % or more, preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 25 mol % or more, yet more preferably 30 mol % or more, further preferably 40 mol % or more, and still further preferably 50 mol % or more, based on all structural units of the resin (A). The total content is also usually 95 mol % or less, preferably 90 mol % or less, more preferably 85 mol % or less, still more preferably 80 mol % or less, yet more preferably 75 mol % or less, further preferably 70 mol % or less, and still further preferably 65 mol % or less, based on all structural units of the resin (A). Specifically, the total content is usually 10 to 95 mol %, preferably 15 to 85 mol %, more preferably 15 to 80 mol %, still more preferably 20 to 80 mol %, yet more preferably 20 to 75 mol %, and further preferably 20 to 70 mol %, based on all structural units of the resin (A).


In the structural unit (a1), examples of the structural unit having a group (2) include a structural unit represented by formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”):




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wherein, in formula (a1-4),

    • Ra32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra33 represents a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group,
    • Aa30 represents a single bond or *—Xa31-(Aa32-Xa32) and * represents a bonding site to carbon atoms to which —Ra32 is bonded,
    • Aa32 represents an alkanediyl group having 1 to 8 carbon atoms,
    • Xa31 and Xa32 each independently represent —O—, —CO—O— or —O—CO—,
    • nc represents 0 or 1,
    • la represents an integer of 0 to 4, and when la is an integer of 2 or more, a plurality of Ra33 may be the same or different from each other, and
    • Ra34 and Ra35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, Ra36 represents a hydrocarbon group having 1 to 20 carbon atoms, or Ra35 and Ra36 may be bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms together with —C—O— to which Ra35 and Ra36 are bonded, and —CH2— included in the hydrocarbon group and the divalent hydrocarbon group may be replaced by —O— or —S—.


Examples of the halogen atom in Ra32 and Ra33 include a fluorine atom, a chlorine atom and a bromine atom.


Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in Ra32 and Ra33 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group and a perfluorohexyl group.


Ra32 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.


Examples of the alkyl group in Ra33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.


Examples of the alkoxy group in Ra33 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group and a hexyloxy group. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and still more preferably a methoxy group.


Examples of the alkoxyalkyl group in Ra33 include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and still more preferably a methoxymethyl group.


Examples of the alkoxyalkoxy group in Ra33 include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group.


Examples of the alkylcarbonyl group in Ra33 include an acetyl group, a propionyl group and a butyryl group. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group.


Examples of the alkylcarbonyloxy group in Ra33 include an acetyloxy group, a propionyloxy group and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group.


Ra33 is preferably a halogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, and still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group or an ethoxyethoxy group.


Examples of the *—Xa31-(Aa32-Xa32)nc— include *—O—, *—CO—O—, *—O—CO—, *—CO—O-Aa32-CO—O—, *—O—CO-Aa32-O—, *—O-Aa32-CO—O—, *—CO—O-Aa32-O—CO— and *—O—CO-Aa32-O—CO. Of these, *—CO—O—, *—CO—O-Aa32-CO—O— or *—O-Aa32-CO—O— is preferable.


Examples of the alkanediyl group in Aa32 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group.


Aa32 is preferably a methylene group or an ethylene group.


Aa30 is preferably a single bond, *—CO—O— or *—CO—O-Aa32-CO—O—, more preferably a single bond, *—CO—O— or *—CO—O—CH2—CO—O—, and still more preferably a single bond or *—CO—O—.


la is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.


Examples of the hydrocarbon group in Ra34, Ra35 and Ra36 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups obtained by combining these groups.


Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like.


The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bonding site).




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Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.


Examples of the combined group include groups obtained by combining the above-mentioned alkyl group and alicyclic hydrocarbon group (e.g., alkylcycloalkyl groups or cycloalkylalkyl groups, such as a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group and a norbornylethyl group), aralkyl groups such as a benzyl group, aromatic hydrocarbon groups having an alkyl group (a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups having an alicyclic hydrocarbon group (a p-cyclohexylphenyl group, a p-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as a phenylcyclohexyl group and the like. Particularly, examples of Ra36 include an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups formed by combining these groups.


When Ra35 and Ra36 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms together with —C—O— to which Ra35 and Ra36 are bonded, examples of the group include the following groups. * represent a bonding site, and one of * represents a bonding site to Ra34.




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Ra34 is preferably a hydrogen atom.


Ra35 is preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a methyl group or an ethyl group.


The hydrocarbon group of Ra36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or groups formed by combining these groups, and more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and the alicyclic hydrocarbon group in Ra36 are preferably unsubstituted. The aromatic hydrocarbon group in Ra36 is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.


—OC(Ra34)(Ra35)—O—Ra36 in the structural unit (a1-4) is eliminated by contacting with an acid (e.g., p-toluenesulfonic acid) to form a hydroxy group or a carboxy group.


—OC(Ra34)(Ra35)—O—Ra36 is preferably bonded at the m-position or the p-position, and more preferably at the p-position of the benzene ring.


The structural unit (a1-4) includes, for example, structural units derived from the monomers mentioned in JP 2010-204646 A. The structural unit preferably includes structural units represented by formula (a1-4-1) to formula (a1-4-32) and a structural unit in which a hydrogen atom corresponding to Ra32 in the structural unit (a1-4) is substituted with a halogen atom, a haloalkyl group or an alkyl group, and more preferably structural units represented by formula (a1-4-1) to formula (a1-4-5), formula (a1-4-10), formula (a1-4-13), formula (a1-4-14), formula (a1-4-19) and formula (a1-4-20).




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When the resin (A) includes the structural unit (a1-4), the content is usually 10 mol % or more, preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 25 mol % or more, yet more preferably 30 mol % or more, further preferably 40 mol % or more, and still further preferably 50 mol % or more, based on the total of all structural units of the resin (A). The content is also usually 95 mol % or less, preferably 90 mol % or less, more preferably 85 mol % or less, still more preferably 80 mol % or less, yet more preferably 75 mol % or less, further preferably 70 mol % or less, and still further preferably 65 mol % or less, based on the total of all structural units of the resin (A). Specifically, the content is also usually 5 to 95 mol %, preferably 10 to 95 mol %, more preferably 15 to 90 mol %, still more preferably 20 to 85 mol %, yet more preferably 20 to 70 mol %, and further preferably 20 to 60 mol %, based on the total of all structural units of the resin (A).


The structural unit derived from a (meth)acrylic monomer having a group (2) also includes a structural unit represented by formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”):




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wherein, in formula (a1-5),

    • RaB represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom,
    • Za1 represents a single bond or *—(CH2)h3—CO-L54-, h3 represents an integer of 1 to 4, and * represents a bonding site to L51,
    • L51, L52, L53 and L54 each independently represent —O— or —S—,
    • s1 represents an integer of 1 to 3, and
    • s1′ represents an integer of 0 to 3.


The halogen atom includes a fluorine atom and a chlorine atom and is preferably a fluorine atom.


Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a fluoromethyl group and a trifluoromethyl group.


In formula (a1-5), RaB is preferably a hydrogen atom, a methyl group or a trifluoromethyl group,

    • L51 is preferably an oxygen atom,
    • one of L52 and L53 is preferably —O— and the other one is preferably —S—,
    • s1 is preferably 1,
    • s1′ is preferably an integer of 0 to 2, and
    • Za1 is preferably a single bond or *—CH2—CO—O—.


The structural unit (a1-5) includes, for example, structural units derived from the monomers mentioned in JP 2010-61117 A. Of these structural units, structural units represented by formula (a1-5-1) to formula (a1-5-4) are preferable, and structural units represented by formula (a1-5-1) or formula (a1-5-2) are more preferable.




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When the resin (A) includes the structural unit (a1-5), the content is usually 1 mol % or more, preferably 2 mol % or more, more preferably 3 mol % or more, still more preferably 5 mol % or more, yet more preferably 10 mol % or more, further preferably 20 mol % or more, and still further preferably 25 mol % or more, based on all structural units of the resin (A). The content is also usually 80 mol % or less, preferably 70 mol % or less, more preferably 60 mol % or less, still more preferably 50 mol % or less, yet more preferably 45 mol % or less, further preferably 40 mol % or less, and still further preferably 30 mol % or less, based on all structural units of the resin (A). Specifically, the content is preferably 1 to 50 mol %, more preferably 3 to 45 mol %, still more preferably 5 to 40 mol %, and yet more preferably 5 to 30 mol %, based on all structural units of the resin (A).


Examples of the structural unit having a group (1) in the structural unit (a1) include a structural unit represented by formula (a1-6) (hereinafter sometimes referred to as “structural unit (a1-6)”):




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wherein, in formula (a1-6),

    • Ra61 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ra62, Ra63 and Ra64 each independently represent an alkyl group having 1 to 6 carbon atoms or a cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, or Ra62 and Ra63 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with carbon atoms to which Ra62 and Ra63 are bonded,
    • Xa61 represents a single bond, —CO—O—* or —CO—NR5—*, * represents a bonding site to —Ar, and R5 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
    • Xa62 represents a single bond, *—O-La61- or *—CO—O-La62-, * represents a bonding site to —Ar, and La61 and La62 each independently represent an alkanediyl group having 1 to 4 carbon atoms, and
    • Ar represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent.


Examples the halogen atom in Ra61 include a fluorine atom, an iodine atom, a chlorine atom and a bromine atom. Of these, a fluorine atom is preferable.


Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in Ra61 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group and a perfluorohexyl group.


Ra61 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.


Examples of the alkyl group in Ra62, Ra63 and Ra64 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group or an ethyl group.


Examples of the cyclic hydrocarbon group in Ra62, Ra63 and Ra64 include an alicyclic hydrocarbon group and an aromatic hydrocarbon group.


The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the like. The number of carbon atoms of the alicyclic hydrocarbon group is preferably 3 to 16, and more preferably 3 to 12.


Examples of the aromatic hydrocarbon group include a phenylene group, a naphthylene group and the like.


Examples of the substituent which may be possessed by the cyclic hydrocarbon group include a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group.


Examples of the ring formed by bonding Ra62 and Ra63 to each other include an adamantane ring, a cyclopentane ring or a cyclohexane ring. Specifically, when Ra62 and Ra63 are bonded to each other to form a ring, examples of —C(Ra62)(Ra63)(Ra64) include the following groups. * represents a bonding site to the oxygen atom. The number of carbon atoms of the ring is preferably 3 to 16, and more preferably 3 to 12.




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Examples of the alkanediyl group having 1 to 4 carbon atoms in La61 and La62 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group and the like.


Preferably, La61 and La62 each independently is a methylene group or an ethylene group.


Xa61 is preferably a single bond or —CO—O—*, and more preferably a single bond.


Xa62 is preferably a single bond or *—O-La61-, and more preferably a single bond.


Examples of the aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group and a phenanthrylene group.


Examples of the substituent which may be possessed by the aromatic hydrocarbon group include a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group or a methacryloyloxy group.


Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.


Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.


Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group and a hexyloxy group. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and still more preferably a methoxy group.


Examples of the alkoxyalkyl group include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and still more preferably a methoxymethyl group.


Examples of the alkoxyalkoxy group include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group.


Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group.


Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group.


The substituent is preferably a halogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, and still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group or an ethoxyethoxy group.


Ar is preferably a phenylene group which may have a substituent, and more preferably a phenylene group which may have a hydroxy group.


Examples of the structural unit (a1-6) include structural units represented respectively by formula (a1-6-1) to formula (a1-6-43), and structural units represented respectively by formula (a1-6-1) to formula (a1-6-9) are preferable, a structural unit represented respectively by formula (a1-6-1), formula (a1-6-2), formula (a1-6-4), formula (a1-6-5), formula (a1-6-7) or formula (a1-6-8) is more preferable, and a structural unit represented respectively by formula (a1-6-1) or formula (a1-6-2) is still more preferable.




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It is also possible to exemplify, as the structural unit (a1-6), structural units in which the hydrogen atom corresponding to Ra61 is substituted with a methyl group, a halogen atom, a haloalkyl group or the like in structural units represented respectively by formula (a1-6-1) to formula (a1-6-9), formula (a1-6-16) to formula (a1-6-21), formula (a1-6-28) to formula (a1-6-30), and formula (a1-6-37) to formula (a1-6-43), and structural units in which the methyl group corresponding to Ra61 is substituted with a hydrogen atom, a halogen atom, a haloalkyl group or the like in structural units represented respectively by formula (a1-6-10) to formula (a1-6-15), formula (a1-6-22) to formula (a1-6-27) and formula (a1-6-31) to formula (a1-6-36).


When the resin (A) includes a structural unit (a1-6), the content is usually 3 mol % or more, preferably 5 mol % or more, more preferably 7 mol % or more, still more preferably 10 mol % or more, yet more preferably 20 mol % or more, further preferably 30 mol % or more, and still further preferably 40 mol % or more, based on all structural units of the resin (A). The content is also usually 80 mol % or less, preferably 75 mol % or less, more preferably 70 mol % or less, and still more preferably 65 mol % or less, based on all structural units of the resin (A). Specifically, the content is preferably 3 to 80 mol %, more preferably 5 to 75 mol %, still more preferably 7 to 70 mol %, further preferably 7 to 65 mol %, and still further preferably 10 to 65 mol %, based on all structural units of the resin (A).


Examples of the structural unit (a1) also include the following structural units.




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When the resin (A) includes structural units represented by formulas (a1-3-1) to (a1-3-7), the content is usually 10 mol % or more, preferably 15 mol % or more, more preferably 20 mol % or more, still more preferably 25 mol % or more, yet more preferably 30 mol % or more, further preferably 40 mol % or more, and still further preferably 50 mol % or more, based on all structural units of the resin (A) or the like. The content is also usually 95 mol % or less, preferably 90 mol % or less, more preferably 85 mol % or less, still more preferably 80 mol % or less, yet more preferably 75 mol % or less, further preferably 70 mol % or less, and still further preferably 60 mol % or less, based on all structural units of the resin (A). Specifically, the content is preferably 10 to 95 mol %, more preferably 15 to 90 mol %, still more preferably 20 to 85 mol %, yet more preferably 20 to 70 mol %, and particularly preferably 20 to 60 mol %, based on all structural units of the resin (A).


<Structural Unit (s)>


The structural unit (s) is derived from a monomer having no acid-labile group (hereinafter sometimes referred to as “monomer (s)”). It is possible to use, as the monomer from which the structural unit (s) is derived, a monomer having no acid-labile group known in the resist field.


The structural unit (s) preferably has a hydroxy group, a carboxy group or a lactone ring. When a resin including a structural unit having a hydroxy group or a carboxy group and having no acid-labile group (hereinafter sometimes referred to as “structural unit (a2)”) and/or a structural unit having a lactone ring and having no acid-labile group (hereinafter sometimes referred to as “structural unit (a3)”) is used in the resist composition of the present invention, it is possible to improve the resolution of a resist pattern and the adhesion to a substrate. Examples of the structural unit (s) include, in addition to the above-mentioned structural units, a structural unit having a halogen atom (hereinafter sometimes referred to as structural unit (a4)), a structural unit having a non-leaving hydrocarbon group (hereinafter sometimes referred to as structural unit (a5)), a structural unit having a sultone structure (hereinafter sometimes referred to as structural unit (a6)), a structural unit which is decomposed upon exposure to radiation to generate an acid (hereinafter sometimes referred to as structural unit (a7)) or other structural units known in the relevant technical field.


<Structural Unit (a2)>


The structural unit (a2) is a structural unit represented by formula (a2) and has an alcoholic hydroxy group, a phenolic hydroxy group or phenolic carboxy group:




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wherein, in formula (a2),

    • Ra2 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Aa21 represents a single bond or an alkanediyl group having 1 to 12 carbon atoms, and —CH2— included in the alkanediyl group may be replaced by —O—, —CO— or —NRa28—,
    • Ra28 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
    • La21 represents a single bond or a hydrocarbon group having 1 to 28 carbon atoms, the hydrocarbon group may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO2—,
    • La22 represents a single bond or a chain hydrocarbon group having 1 to 12 carbon atoms which may have a fluorine atom, and —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—, and
    • na2 represents an integer of 1 to 5, and when na2 is 2 or more, a plurality of La22 may be the same or different from each other.


Examples of the halogen atom in Ra2 include a fluorine atom, a chlorine atom and a bromine atom.


Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in Ra2 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, a perfluorohexyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group and the like. The number of carbon atoms of the alkyl group is preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 or 2.


Ra2 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.


Examples of the alkanediyl group as for Aa21 include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group and a dodecane-1,12-diyl group; and branched alkanediyl groups such as a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group, a heptane-1,6-diyl group, an octane-1,7-diyl group, a nonane-1,8-diyl group and a decane-1,9-diyl group.


The number of carbon atoms of the alkanediyl group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, yet more preferably 1 to 4, further preferably 1 to 3, and still further preferably 1 or 2. Aa21 is also preferably a methylene group or an ethylene group.


Examples of the alkyl group as for Ra28 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and a tert-butyl group.


When —CH2— included in the alkanediyl group as for Aa21 is replaced by —O—, —CO— or —NRa28—, the number of carbon atoms before replacement is taken as the number of carbon atoms of the alkanediyl group.


Examples of the group in which —CH2— included in the alkanediyl group as for Aa21 is replaced by —O—, —CO— or —NRa28 include a hydroxy group (a group in which —CH2— included in the methyl group is replaced by —O—), a carboxy group (a group in which —CH2—CH2— included in the ethyl group is replaced by —O—CO—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), an amino group (a group in which —CH2— included in the methyl group is replaced by —NRa28—), an alkoxy group (a group in which —CH2— at any position included in the alkyl group is replaced by —O—), an alkoxycarbonyl group (in which —CH2—CH2— at any position included in the alkyl group is replaced by —O—CO—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylamino group (a group in which —CH2— at any position included in the alkyl group is replaced by —NRa28—), a peptide group (a group in which —CH2—CH2— included in the ethylene group is replaced by —CO—NRa28—), an alkanediylamino group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —NRa28—) and the like. Examples of these replaced groups include those which are the same as mentioned herein.


Examples of the alkylamino group include alkylamino groups having 1 to 11 carbon atoms, for example, a methylamino group, an ethylamino group, a propylamino group, a butylamino group, a pentylamino group, a hexylamino group, an octylamino group and the like. The number of carbon atoms of the alkylamino group is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Examples of the alkanediylamino group include alkanediylamino groups having 1 to 11 carbon atoms, for example a methyleneamino group, an ethyleneamino group, a propyleneamino group and the like. The number of carbon atoms of the alkanediylamino group is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


Of these, examples of the group in which —CH2-included in the alkanediyl group is replaced by —O—, —CO— or —NRa28 as for Aa21 include *—O—, *—CO—O—, *—O—CO—, *—CO—O-Aa22-CO—O—, *—O—CO-Aa22-O—, *—O-Aa22-CO—O—, *—CO—O-Aa22-O—CO—, *—O—CO-Aa22-O—CO— and *—CO—NRa28—. Of these, *—CO—O—, *—CO—O-Aa22-CO—O— or *—O-Aa22-CO—O—, *—CO—NRa28— is preferable. Here, Aa22 represents an alkanediyl group having 1 to 8 carbon atoms, and * represents a bonding site to carbon atoms to which Ra2 is bonded. Examples of the alkanediyl group as for Aa22 include the same alkanediyl group as for Aa21 as long as the upper limit of the number of carbon atoms permit.


Aa21 is preferably a single bond, *—CO—O— or *—CO—O-Aa22-CO—O—, more preferably a single bond, *—CO—O— or *—CO—O—CH2—CO—O—, and still more preferably a single bond or *—CO—O—.


The hydrocarbon group in La2 is an (na2+1)-valent hydrocarbon group, and examples thereof include a linear or branched chain hydrocarbon group, cyclic hydrocarbon groups such as a monocyclic or polycyclic (including a spiro ring, a fused ring or a bridged ring) alicyclic hydrocarbon group and an aromatic hydrocarbon group, and the hydrocarbon group may be groups obtained by combining two or more of these groups (e.g., a hydrocarbon group formed from an alicyclic hydrocarbon group or an aromatic hydrocarbon group and a chain hydrocarbon group).


Examples of the chain hydrocarbon group as for La2 include di- to hexa-valent chain hydrocarbon groups such as an alkanediyl group, an alkanetriyl group, an alkanetetrayl group, an alkanepentayl group and an alkanehexayl group.


Examples of the alkanediyl group include the same alkanediyl groups as for Aa21.


Examples of the alkanetriyl group include a methanetriyl group, an ethanetriyl group, a propanetriyl group, a butanetriyl group, a pentanetriyl group, a hexanetriyl group, a heptanetriyl group, an octanetriyl group, a nonanetriyl group, a decanetriyl group, an undecanetriyl group, a dodecanetriyl group, a tridecanetriyl group, a tetradecanetriyl group, a pentadecanetriyl group, a hexadecanetriyl group and a heptadecanetriyl group.


Examples of the alkanetetrayl group include a methanetetrayl group, an ethanetetrayl group, a propanetetrayl group, a butanetetrayl group, a pentanetetrayl group, a hexanetetrayl group, a heptanetetrayl group, an octanetetrayl group, a nonanetetrayl group, a decanetetrayl group, an undecanetetrayl group, a dodecanetetrayl group, a tridecanetetrayl group, a tetradecanetetrayl group, a pentadecanetetrayl group, a hexadecanetetrayl group and a heptadecanetetrayl group.


Examples thereof also include groups in which one or more hydrogen atoms of the above-mentioned groups are substituted with a bonding site.


The number of carbon atoms of the chain hydrocarbon group is preferably 1 to 18, more preferably 1 to 12, still more preferably 1 to 10, yet more preferably 1 to 9, further preferably 1 to 8, still further preferably 1 to 6, yet further preferably 1 to 5, and particularly preferably 1 to 4.


Examples of the monocyclic and polycyclic alicyclic hydrocarbon group in La21 include the following alicyclic hydrocarbon groups and the like. The bonding site can be any position.




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Examples thereof include di- to hexa-valent alicyclic hydrocarbon groups such as a cycloalkanediyl group, a cycloalkanetriyl group, a cycloalkanetetrayl group, a cycloalkanepentayl group and a cycloalkanehexayl group.


Specific examples thereof include monocyclic alicyclic hydrocarbon groups such as a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cyclooctane-1,5-diyl group, a cyclopropanetriyl group, a cyclobutanetriyl group, a cyclopentanetriyl group, a cyclohexanetriyl group, a cycloheptanetriyl group, a cyclooctanetriyl group, a cyclodecanetriyl group, a cyclopropanetetrayl group, a cyclobutanetetrayl group, a cyclopentanetetrayl group, a cyclohexanetetrayl group, a cycloheptanetetrayl group, a cyclooctanetetrayl group and a cyclodecanetetrayl group, and

    • polycyclic alicyclic hydrocarbon groups such as a norbornane-1,4-diyl group, a norbornane-2,5-diyl group, a adamantane-1,5-diyl group, an adamantane-2,6-diyl group, a decahydronaphthalenediyl group, a bicyclo[3.3.0]octanediyl group, a norbornanetriyl group, an adamantanetriyl group, a decahydronaphthalenetriyl group, a bicyclo[3.3.0]octanetriyl group, a norbornanetetrayl group, an adamantanetetrayl group, a decahydronaphthalenetetrayl group and a bicyclo[3.3.0]octanetetrayl group.


Examples thereof also include groups in which one or more hydrogen atoms of the above-mentioned groups are substituted with a bonding site.


The number of carbon atoms of the alicyclic hydrocarbon group is preferably 3 to 20, more preferably 3 to 18, still more preferably 3 to 16, and yet more preferably 3 to 12.


Examples of the aromatic hydrocarbon group in La21 include di- to hexa-valent aromatic hydrocarbon groups such as an arylene group, an arenetriyl group, an arenetetrayl group, an arenepentayl group and an arenehexayl group.


Specific examples thereof include aromatic hydrocarbon groups such as a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group, a phenanthrylene group, a benzenetriyl group, a naphthalenetriyl group, a anthracenetriyl group, a biphenylenetriyl group, a phenanthrenetriyl group, a benzenetetrayl group, a naphthalenetetrayl group, an anthracenetetrayl group, a biphenylenetetrayl group and a phenanthrenetetrayl group.


Examples thereof also include groups in which one or more hydrogen atoms of the above-mentioned groups are substituted with a bonding site.


The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 to 20, more preferably 6 to 18, still more preferably 6 to 14, and yet more preferably 6 to 10.


Examples of the group obtained by combining two or more groups include a group obtained by combining an alicyclic hydrocarbon group with a chain hydrocarbon group, a group obtained by combining an aromatic hydrocarbon group with a chain hydrocarbon group, a group obtained by combining an alicyclic hydrocarbon group with an aromatic hydrocarbon group, and a group obtained by combining an alicyclic hydrocarbon group, a chain hydrocarbon group and an aromatic hydrocarbon group. In combination, two or more of alicyclic hydrocarbon groups, aromatic hydrocarbon groups and chain hydrocarbon groups may be respectively combined. Any group may be bonded to Aa21 and La22.


Examples of the group in which —CH2— included in the hydrocarbon group is replaced by —O—, —S—, —SO2— or —CO— include a hydroxy group (a group in which —CH2— included in methyl group is replaced by —O—), a carboxy group (a group in which —CH2—CH2— included in ethyl group is replaced by —O—CO—), a thiol group (a group in which —CH2— included in methyl group is replaced by —S—), an alkoxy group (a group in which —CH2— at any position included in alkyl group is replaced by —O—), an alkylthio group (a group in which —CH2— at any position included in alkyl group is replaced by —S—), an alkoxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —O—CO—), an alkylsulfonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —SO2—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —CO—O—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), a thio group (a group in which —CH2— included in methylene group is replaced by —S—), a sulfonyl group (a group in which —CH2— included in the methylene group is replaced by —SO2—), an alkanediyloxy group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —O—), an alkanediyloxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —CO—), an alkanediylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —CO—O—), an alkanediylsulfonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —SO2—), an alkanediylthio group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —S—), a cycloalkoxy group, a cycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatic hydrocarbon group-carbonyloxy group, an aromatic hydrocarbon group-carbonyl group, an aromatic hydrocarbon group-oxy group, and groups obtained by combining two or more of these group. Examples thereof also include groups in which one or more hydrogen atoms of the above-mentioned groups are substituted with a bonding site. Examples of these replaced groups include the same groups as mentioned herein.


Examples of the group in which —CH2— included in the alicyclic hydrocarbon group is replaced by —O—, —S—, —CO— or —SO2— include the same groups as mentioned herein.


Examples of the group in which —CH2— included in the combined group is replaced by —O—, —S—, —CO— or —SO2— also include the following groups. The bonding site can be any position.




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The hydrocarbon group in La21 may have one or a plurality of substituents. Examples of the substituent include a halogen atom, a haloalkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 16 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), an acryloyloxy group or a methacryloyloxy group.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.


The hydrocarbon group in La21 can substantially have a substituent such as a haloalkyl group by having a halogen atom as the substituent. Examples of the haloalkyl group include an alkyl fluoride group, an alkyl chloride group, an alkyl bromide group, an alkyl iodide group, for example, a chloromethyl group, a bromomethyl group, an iodomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group and the like. The number of carbon atoms of the haloalkyl group is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3.


The hydrocarbon group as for La21 can substantially have a substituent such as an alkyl group by including a branched structure in La21. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, an octyl group, a nonyl group, a decyl group, an undecyl group and a dodecyl group. The number of carbon atoms of the alkyl group is preferably 1 to 12, more preferably 1 to 10, still more preferably 1 to 8, yet more preferably 1 to 6, further preferably 1 to 4, and still further preferably 1 to 3.


La2 can substantially have a substituent such as a hydroxy group, a carboxy group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylcarbonyloxy group, an alkoxyalkyl group, an alkoxyalkoxy group, an acryloyloxy group or a methacryloyloxy group, by the group in which —CH2— included in the hydrocarbon group is replaced by —O— or —CO— as for La22. The number of carbon atoms of the alkoxy group is preferably 1 to 12, more preferably 1 to 6, still more preferably 1 to 4, and yet more preferably 1 to 3. The number of carbon atoms of the alkoxycarbonyl group, the alkylcarbonyl group and the alkylcarbonyloxy group is preferably 2 to 12, more preferably 2 to 6, still more preferably 2 to 4, and yet more preferably 2 to 3. The number of carbon atoms of the alkoxyalkyl group and the alkoxyalkoxy group is preferably 2 to 12, more preferably 2 to 8, still more preferably 2 to 6, and yet more preferably 2 to 4.


Examples of the above group include those which are the same as mentioned herein.


The substituent which may be possessed by the hydrocarbon group in La21 is preferably a halogen atom, a haloalkyl group having 1 to 8 carbon atoms or an alkyl group having 1 to 12 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), more preferably a halogen atom, a haloalkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 10 carbon atoms (—CH2— included in the alkyl group may be replaced by —O— or —CO—), still more preferably a halogen atom, a haloalkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, a hydroxy group, alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, yet more preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a methyl group, a hydroxy group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, and still preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a methyl group, a hydroxy group, a methoxy group or an ethoxyethoxy group.


When the alkanediyl group is replaced by —O— or —CO— as for La21, for example, it is also preferably *-La23-Xa21-(La23 represents an alkanediyl group having 1 to 8 carbon atoms, Xa21 represents —O—, —O—CO—, —CO—O— or —O—CO—O—, and * represents a bonding site to Aa21).


La21 is preferably a single bond, a chain hydrocarbon group having 1 to 12 carbon atoms which may have a substituent (in which —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—), a cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent (in which —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—), or groups obtained by combining a chain hydrocarbon group having 1 to 8 carbon atoms which may have a substituent with a cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent (in which —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —SO2— or —CO—), and more preferably a chain hydrocarbon group having 1 to 10 carbon atoms which may have a substituent (in which —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—), a cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (in which —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—), or groups obtained by combining a chain hydrocarbon group having 1 to 6 carbon atoms which may have a substituent with a cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (in which —CH2— included in the chain hydrocarbon group may be replaced by —O— or —CO—, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —SO2— or —CO—).


Examples of the chain hydrocarbon group having 1 to 12 carbon atoms as for La22 include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group and a dodecane-1,12-diyl group; and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a 1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a 1-dimethylpropane-1,3-diyl group, a pentane-2,4-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group. The number of carbon atoms of the chain hydrocarbon group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, and yet more preferably 1 to 4.


Examples of the group in which —CH2— included in the chain hydrocarbon group is replaced by —O— or —CO— include the same groups as mentioned herein.


The number of fluorine atoms possessed by La22 may be either 1, or 2 or more.


na2 is preferably an integer of 1 to 4, and more preferably an integer of 1 to 3.


Examples of the structural unit (a2) when La21 is a single bond or a chain hydrocarbon group include the following structural units. Of the following structural units, the structural unit in which the methyl group corresponding to Ra2 is substituted with a hydrogen atom or the like is preferable structural unit of the structural unit (a2), similarly to the following structural units.




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When a resist pattern is produced from the resist composition of the present invention, in the case of using, as an exposure source, high energy rays such as KrF excimer laser (248 nm), electron beam or extreme ultraviolet light (EUV), a structural unit (a2) having a phenolic hydroxy group is preferably used, and the below-mentioned structural unit (a2-A) is more preferably used, as the structural unit (a2). When using ArF excimer laser (193 nm) or the like, a structural unit (a2) having an alcoholic hydroxy group is preferably used, and the below-mentioned structural unit (a2-1) is more preferably used, as the structural unit (a2). The structural unit (a2) may be included alone, or two or more structural units may be included.


In the structural unit (a2), when La21 is a cyclic hydrocarbon group, examples of the structural unit having a phenolic hydroxy group include a structural unit represented by formula (a2-A) (hereinafter sometimes referred to as “structural unit (a2-A)”):




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wherein, in formula (a2-A),

    • Ra2 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Aa21 represents a single bond or an alkanediyl group having 1 to 12 carbon atoms, and —CH2— included in the alkanediyl group may be replaced by —O—, —CO— or —NRa28—, and
    • Ra28 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
    • Xa2 represents a single bond or —CO—,
    • Ra27 represents a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group,
    • nA2 represents an integer of 1 to 5, and when nA2 is 2 or more, a plurality of Xa2 may be the same or different from each other, and
    • nA22 represents an integer of 0 to 4, and when nA22 is 2 or more, a plurality of Ra27 may be the same or different from each other.


Examples of Ra2, Aa21 and Ra28 include groups which are the same as mentioned in formula (a2), respectively.


Examples of the halogen atom and an alkyl group which may have a halogen atom as for Ra27 include groups which are the same as mentioned for Ra2 or the substituent of La21 in formula (a2), respectively.


Examples of the alkoxy group as for Ra27 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group and a tert-butoxy group. The number of carbon atoms of the alkoxy group is preferably 1 to 4, and more preferably 1 to 3. The alkoxy group is preferably a methoxy group or an ethoxy group, and more preferably a methoxy group.


Examples of the alkoxyalkyl group as for Ra27 include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group and a tert-butoxymethyl group. The number of carbon atoms of the alkoxyalkyl group is preferably 2 to 8, and more preferably 2 to 4. The alkoxyalkyl group is preferably a methoxymethyl group or an ethoxyethyl group, and more preferably a methoxymethyl group.


Examples of the alkoxyalkoxy group as for Ra27 include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group and a tert-butoxymethoxy group. The number of carbon atoms of the alkoxyalkoxy group is preferably 2 to 8, and more preferably 2 to 4. The alkoxyalkoxy group is preferably a methoxyethoxy group or an ethoxyethoxy group.


Examples of the alkylcarbonyl group as for Ra27 include an acetyl group, a propionyl group and a butyryl group. The number of carbon atoms of the alkylcarbonyl group is preferably 2 to 4, and more preferably 2 to 3. The alkylcarbonyl group is preferably an acetyl group.


Examples of the alkylcarbonyloxy group as for Ra27 include an acetyloxy group, a propionyloxy group and a butyryloxy group. The number of carbon atoms of the alkylcarbonyloxy group is preferably 2 to 4, and more preferably 2 to 3. The alkylcarbonyloxy group is preferably an acetyloxy group.


Ra27 is preferably a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 4 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, and still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group or an ethoxyethoxy group.


Xa2 is preferably a single bond.


nA22 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


nA2 is preferably 1, 2, 3 or 4, more preferably 1, 2 or 3, and still more preferably 1 or 2.


At least one hydroxy group is preferably bonded at the meta-position or the para-position, and more preferably at the meta-position, of the benzene ring. When two hydroxy groups are bonded to the benzene ring, each hydroxy group is preferably bonded at the meta-position and the para-position.


Examples of the structural unit (a2-A) include structural units derived from the monomers mentioned in JP 2010-204634 A and JP 2012-12577 A.


Examples of the structural unit (a2-A) include structural units represented by formula (a2-2-1) to formula (a2-2-32), and a structural unit in which a methyl group corresponding to Ra2 in the structural unit (a2-A) is substituted with a hydrogen atom, a halogen atom, a haloalkyl group or other alkyl groups in structural units represented by formula (a2-2-1) to formula (a2-2-32). The structural unit (a2-A) is preferably structural units represented by formula (a2-2-1) to formula (a2-2-4), formula (a2-2-6), formula (a2-2-8) and formula (a2-2-12) to formula (a2-2-18), and a structural unit in which a methyl group corresponding to Ra2 in the structural unit (a2-A) is substituted with a hydrogen atom in structural units represented by formula (a2-2-1) to formula (a2-2-4), formula (a2-2-6), formula (a2-2-8) and formula (a2-2-12) to formula (a2-2-18); more preferably a structural units represented by formula (a2-2-3), formula (a2-2-4), formula (a2-2-8), formula (a2-2-12) to formula (a2-2-14) and formula (a2-2-18), and a structural unit in which a methyl group corresponding to Ra2 in the structural unit (a2-A) is substituted with a hydrogen atom in structural units represented by formula (a2-2-3), formula (a2-2-4), (a2-2-8), (a2-2-12) to formula (a2-2-14) and (a2-2-18); and still more preferably structural units represented by formula (a2-2-3), formula (a2-2-4) and formula (a2-2-8), and a structural unit in which a methyl group corresponding to Ra2 in the structural unit (a2-A) is substituted with a hydrogen atom in structural units represented by formula (a2-2-3), formula (a2-2-4) and formula (a2-2-8).




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When the structural unit (a2-A) is included in the resin (A), the content of the structural unit (a2-A) is preferably 5 mol % or more, more preferably 10 mol % or more, still more preferably 15 mol % or more, and yet more preferably 20 mol % or more, based on all structural units. The content is also preferably 80 mol % or less, more preferably 70 mol % or less, still more preferably 65 mol % or less, yet more preferably 60 mol % or less, further preferably 50 mol % or less, still further preferably 45 mol % or less, and yet further preferably 40 mol % or less, based on all structural units. Specifically, the content is preferably 5 to 80 mol %, more preferably 10 to 70 mol %, still more preferably 15 to 65 mol %, and yet more preferably 20 to 65 mol %, based on all structural units.


The structural unit (a2-A) can be included in the resin (A) by polymerizing, for example, with a structural unit (a1-4) and treating with an acid such as p-toluenesulfonic acid. The structural unit (a2-A) can also be included in the resin (A) by polymerizing with acetoxystyrene and treating with an alkali such as tetramethylammonium hydroxide.


In the structural unit (a2), when La21 is a cyclic hydrocarbon group, examples of the structural unit having an alcoholic hydroxy group or the like include a structural unit represented by formula (a2-B) (hereinafter sometimes referred to as “structural unit (a2-B)”), a structural unit represented by formula (a2-C) (hereinafter sometimes referred to as “structural unit (a2-C)”) or a structural unit represented by formula (a2-D) (hereinafter sometimes referred to as “structural unit (a2-D)”):




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wherein, in formula (a2-B) and formula (a2-C),

    • Ra2 is the same as defined in formula (a2),
    • Ra27 is the same as defined in formula (a2-A),
    • La25 represents —O— or *—O—(CH2)k2—CO—O—,
    • k2 represents an integer of 1 to 7, and * represents a bonding site to —CO—,
    • Xa2 represents a single bond or —CO—,
    • Ra25 and Ra26 each independently represent a hydrogen atom, a methyl group or a hydroxy group, and
    • nB2 represents an integer of 1 to 5, and when nB2 is 2 or more, a plurality of Xa2 may be the same or different from each other,
    • nB22 represents an integer of 0 to 8, and when nB22 is 2 or more, a plurality of Ra27 may be the same or different from each other,
    • nC22 represents an integer of 0 to 10, and when nC22 is 2 or more, a plurality of Ra27 may be the same or different from each other.


La25 is preferably —O—, —O—(CH2)f1—CO—O— (f1 represents an integer of 1 to 4), and more preferably —O—.


Ra2 is preferably a methyl group.


Xa2 is preferably a single bond.


Ra25 is preferably a hydrogen atom.


Ra26 is preferably a hydrogen atom or a hydroxy group.


Ra27 is preferably a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 4 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group or an ethoxyethoxy group.


nB2 is preferably 1, 2, 3 or 4, more preferably 1, 2 or 3, and still more preferably 1 or 2.


nB22 is preferably an integer of 0 to 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


nC22 is preferably an integer of 0 to 6, more preferably an integer of 0 to 3, and still more preferably 0 or 1.


Examples of the structural unit (a2-B) and the structural unit (a2-C) include a structural unit derived from the monomer mentioned in JP 2010-204646 A, the following structural units, and structural units in which the methyl group or the hydrogen atom corresponding to Ra2 in the following structural units is substituted with a hydrogen atom, a halogen atom, a haloalkyl group, or other alkyl groups. Of these, a structural unit represented by any one of formula (a2-B-1) to formula (a2-B-5) and formula (a2-C-1) to formula (a2-C-9) is preferable.




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When the resin (A) includes a structural unit (a2-B) or a structural unit (a2-C), the content is usually 1 mol % or more, and preferably 2 mol % or more, based on all structural units of the resin (A). The content is also usually 45 mol % or less, preferably 40 mol % or less, more preferably 35 mol % or less, still more preferably 20 mol % or less, and yet more preferably 10 mol % or less, based on all structural units of the resin (A). Specifically, the content is usually 1 to 45 mol %, preferably 1 to 40 mol %, more preferably 1 to 35 mol %, still more preferably 1 to 20 mol %, and yet more preferably 1 to 10 mol %, based on all structural units of the resin (A).




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wherein, in formula (a2-D),

    • Ra2 and Aa21 are respectively the same as defined in formula (a2),
    • Ra27 is the same as defined in formula (a2-A),
    • Ra2 and Ra22 each independently represent an alkyl fluoride group having 1 to 4 carbon atoms, and
    • La24 represents a single bond or an alkanediyl group having 1 to 3 carbon atoms, and the alkanediyl group may be substituted with a fluorine atom.
    • nD2 represents an integer of 1 to 5, and when nD2 is 2 or more, a plurality of groups in parentheses may be the same or different from each other,
    • nD22 represents an integer of 0 to 4, and when nD22 is 2 or more, a plurality of Ra27 may be the same or different from each other.


Examples of the alkyl fluoride group as for Ra21 and Ra22 each independently include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 4,4,4-trifluorobutyl group and the like.


Ra2 and Ra22 are preferably a trifluoromethyl group.


Examples of the alkanediyl group as for La24 include a methylene group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-2,2-diyl group and the like.


La24 is preferably a single bond or a methylene group.


Ra27 is preferably a halogen atom, a hydroxy group, a carboxy group, an alkyl group having 1 to 4 carbon atoms which may have a halogen atom, an alkoxy group having 1 to 4 carbon atoms or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group, and still more preferably, a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group or an ethoxyethoxy group.


nD22 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still more preferably 0 or 1.


nD2 is preferably 1, 2, 3 or 4, more preferably 1, 2 or 3, and still more preferably 1 or 2.


The structural unit (a2-D) is more preferably a structural unit represented by the following formula (a2-D1) (hereinafter sometimes referred to as “structural unit (a2-D1)”):




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wherein, in formula (a2-D1),

    • Ra2, Aa21, Ra27, nD2 and nD22 are respectively the same as defined in formula (a2-D).


Examples of the structural unit (a2-D) include structural units mentioned below.




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It is possible to exemplify structural units in which the hydrogen atom corresponding to Ra2 is substituted with a methyl group or the like in structural units represented by formula (a2-D-1) to formula (a2-D-8), and structural units in which the methyl group corresponding to Ra2 is substituted with a hydrogen atom in structural units represented by formula (a2-D-9) to formula (a2-D-16) as specific examples of the structural unit (a2-D). Of these, structural units represented by formula (a2-D-1) to formula (a2-D-8) are preferable, structural units represented by formula (a2-D-1) to formula (a2-D-4) are more preferable, and a structural unit represented by formula (a2-D-1) is still more preferable.


When the resin (A) includes the structural unit (a2-D), the content is preferably 3 mol % or more, more preferably 5 mol % or more, and still more preferably 10 mol % or more, based on all structural units of the resin (A). The content is also preferably 80 mol % or less, more preferably 75 mol % or less, still more preferably 70 mol % or less, and yet more preferably 65 mol % or less, based on all structural units of the resin (A). Specifically, the content is preferably 3 to 80 mol %, more preferably 5 to 75 mol %, still more preferably 10 to 70 mol %, and yet more preferably 10 to 65 mol %, based on all structural units of the resin (A).


<Structural Unit (a3)>


The lactone ring possessed by the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring or a δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and the other ring. Preferably, a γ-butyrolactone ring, an adamantanelactone ring or a bridged ring including a γ-butyrolactone ring structure (e.g., a structural unit represented by the following formula (a3-2)) is exemplified.


The structural unit (a3) is preferably a structural unit represented by formula (a3-1), formula (a3-2), formula (a3-3) or formula (a3-4). These structural units may be included alone, or two or more structural units may be included:




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wherein, in formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4),

    • La4, La5 and La6 each independently represent —O— or a group represented by *—O—(CH2)k3—CO—O— (k3 represents an integer of 1 to 7),
    • La7 represents —O—, *—O-La8-O—, *—O-La8-CO—O—, *—O-La8-CO—O-La9-CO—O— or *—O-La8-O—CO-La9-O—,
    • La8 and La9 each independently represent an alkanediyl group having 1 to 6 carbon atoms,
    • * represents a bonding site to a carbonyl group,
    • Ra18, Ra19, Ra20 and Ra24 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Xa3 represents —CH2— or an oxygen atom,
    • Ra21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms,
    • Ra22, Ra23 and Ra25 each independently represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms,
    • p1 represents an integer of 0 to 5,
    • q1 represents an integer of 0 to 3,
    • r1 represents an integer of 0 to 3,
    • w1 represents an integer of 0 to 8, and
    • when p1, q1, r1 and/or w1 are 2 or more, a plurality of Ra2, Ra22, Ra23 and/or Ra25 may be the same or different from each other.


Examples of the aliphatic hydrocarbon group in Ra2, Ra22, Ra23 and Ra25 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group.


Examples of the halogen atom in Ra18, Ra19, Ra20 and Ra24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the alkyl group in Ra18, Ra19, Ra20 and Ra24 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group, and the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.


Examples of the alkyl group having a halogen atom in Ra18, Ra19, Ra20 and Ra24 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group and the like.


Examples of the alkanediyl group in La8 and La9 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group.


In formula (a3-1) to formula (a3-3), preferably, La4 to La6 are each independently —O— or a group in which k3 is an integer of 1 to 4 in *—O—(CH2)k3—CO—O—, more preferably —O— and *—O—CH2—CO—O—, and still more preferably an oxygen atom,

    • Ra18 to Ra21 are preferably a methyl group,
    • preferably, Ra22 and Ra23 are each independently a carboxy group, a cyano group or a methyl group, and
    • preferably, p1, q1 and r1 are each independently an integer of 0 to 2, and more preferably 0 or 1.


In formula (a3-4), Ra24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group,

    • Ra25 is preferably a carboxy group, a cyano group or a methyl group,
    • La7 is preferably —O— or *—O-La8-CO—O—, and more preferably —O—, —O—CH2—CO—O— or —O—C2H4—CO—O—, and
    • w1 is preferably an integer of 0 to 2, and more preferably 0 or 1.


Particularly, formula (a3-4) is preferably formula (a3-4)′:




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wherein Ra24 and La7 are the same as defined above.


Examples of the structural unit (a3) include structural units derived from the monomers mentioned in JP 2010-204646 A, the monomers mentioned in JP 2000-122294 A and the monomers mentioned in JP 2012-41274 A. The structural unit (a3) is preferably a structural unit represented by any one of formula (a3-1-1), formula (a3-1-2), formula (a3-2-1), formula (a3-2-2), formula (a3-3-1), formula (a3-3-2) and formula (a3-4-1) to formula (a3-4-12), and structural units in which methyl groups corresponding to Ra18, Ra19, Ra20 and Ra24 in formula (a3-1) to formula (a3-4) are substituted with hydrogen atoms in the above structural units.




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When the resin (A) includes the structural unit (a3) the total content is usually 1 mol % or more, preferably 3 mol % or more, more preferably 5 mol % or more, and still more preferably 10 mol % or more, based on all structural units of the resin (A). The total content is also usually 70 mol % or less, preferably 65 mol or less, and more preferably 60 mol or less, based on all structural units of the resin (A). Specifically, the total content is usually 1 to 70 mol % preferably 3 to 65 mol %, and more preferably 5 to 60 mol based on all structural units of the resin (A).


Each content of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3) or the structural unit (a3-4) is preferably 1 mol % or more, more preferably 3 mol % or more, and still more preferably 5 mol or more, based on all structural units of the resin (A). The content is also preferably 60 mol or less, more preferably 55 mol % or less, and still more preferably 50 mol % or less, based on all structural units of the resin (A). Specifically, the content is preferably 1 to 60 mol %, more preferably 3 to 55 mol %, and still more preferably 5 to 50 mol %, based on all structural units of the resin (A).


<Structural Unit (a4)>


The structural unit represented by formula (a4) is a structural unit represented by the following:




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wherein, in formula (a4),

    • R41 represents a hydrogen atom or a methyl group, and
    • R42 represents a saturated hydrocarbon group having 1 to 24 carbon atoms which has a halogen atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—.


Examples of the saturated hydrocarbon group represented by R42 include a linear or branched chain saturated hydrocarbon group and a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and groups formed by combining these groups.


Examples of the chain saturated hydrocarbon group include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group and an octadecyl group; and branched alkyl groups such as an isopropyl group and an isobutyl group.


Examples of the monocyclic or polycyclic saturated alicyclic hydrocarbon group include monocyclic alicyclic saturated hydrocarbon groups which are monocyclic cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group; and polycyclic alicyclic saturated hydrocarbon groups which are polycyclic cycloalkyl groups such as a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* represents a bonding site).




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Examples of the groups formed by combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic saturated hydrocarbon groups, for example, an -alkanediyl group-alicyclic saturated hydrocarbon group, an -alicyclic saturated hydrocarbon group-alkyl group, an -alkanediyl group-alicyclic saturated hydrocarbon group-alkyl group and the like.


Examples of the alkanediyl group include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group and a hexane-1,6-diyl group; and branched alkanediyl groups such as a propane-1,2-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a 1-methylbutane-1,4-diyl group and a 2-methylbutane-1,4-diyl group. The end of the branched alkanediyl group may be a methyl group.


Examples of the halogen atom possessed by the saturated hydrocarbon group included in R42 include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.


Examples of the group in which —CH2— of the saturated hydrocarbon group included in R42 is replaced by —O— or —CO— include a hydroxy group (a group in which —CH2— included in the methyl group is replaced by —O—), a carboxy group (a group in which —CH2—CH2— included in the ethyl group is replaced by —O—CO—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), an alkoxy group (a group in which —CH2— at any position included in the alkyl group is replaced by —O—), an alkoxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —O—CO—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —CO—O—), an alkanediyloxy group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —O—), an alkanediyloxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —CO—), an alkanediylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —CO—O—), a cycloalkoxy group, a cycloalkylalkoxy group, groups obtained by combining two or more of these groups and the like. Examples of these replaced groups include the same groups as mentioned herein as long as the upper limit of the number of carbon atoms permits.


The structural unit (a4) is preferably a structural unit in which R42 is a saturated hydrocarbon group having a fluorine atom. An example of the structural unit (a4) in which R42 is a saturated hydrocarbon group having a fluorine atom include a structural unit represented by formula (a4-1) (hereinafter sometimes referred to as structural unit (a4-1)), a structural unit represented by formula (a4-2) (hereinafter sometimes referred to as structural unit (a4-2)) and a structural unit represented by formula (a4-3) (hereinafter sometimes referred to as structural unit (a4-3)).


The structural unit represented by formula (a4-1) is a structural unit represented by the following:




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wherein, in formula (a4-1),

    • R41 represents a hydrogen atom or a methyl group,
    • L41 represents a single bond or an alkanediyl group having 1 to 4 carbon atoms,
    • L42f represents an alkanediyl group having 1 to 8 carbon atoms which has a fluorine atom, or a cycloalkanediyl group having 3 to 12 carbon atoms which has a fluorine atom, and
    • R42f represents a hydrogen atom or a fluorine atom.


Examples of the alkanediyl group in L41 include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group and a butane-1,4-diyl group; and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,2-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group and a 2-methylpropane-1,2-diyl group. The end of the branched alkanediyl group may be a methyl group.


Examples of the alkanediyl group having a fluorine atom in L42f include linear alkanediyl groups having a fluorine atom, such as a methylene group having a fluorine atom, an ethylene group having a fluorine atom, a propane-1,3-diyl group having a fluorine atom, a butane-1,4-diyl group having a fluorine atom, a pentane-1,5-diyl group having a fluorine atom, a hexane-1,6-diyl group having a fluorine atom, a heptane-1,7-diyl group having a fluorine atom and an octane-1,8-diyl group having a fluorine atom; and

    • branched alkanediyl group having a fluorine atom, such as an ethane-1,1-diyl group having a fluorine atom, a propane-1,1-diyl group having a fluorine atom, a propane-1,2-diyl group having a fluorine atom, a propane-2,2-diyl group having a fluorine atom, a pentane-2,4-diyl group having a fluorine atom, a 2-methylpropane-1,3-diyl group having a fluorine atom, a 2-methylpropane-1,2-diyl group having a fluorine atom, a pentane-1,4-diyl group having a fluorine atom and a 2-methylbutane-1,4-diyl group having a fluorine atom. The end of the branched alkanediyl group may be a methyl group which may have a fluorine atom.


Examples of cycloalkanediyl group having a fluorine atom in L42f include monocyclic cycloalkanediyl groups having a fluorine atom, such as a cyclobutane-1,3-diyl group having a fluorine atom, a cyclopentane-1,3-diyl group having a fluorine atom, a cyclohexane-1,4-diyl group having a fluorine atom, a cyclohexene-3,6-diyl group having a fluorine atom, a cycloheptane-1,4-diyl group having a fluorine atom and a cyclooctane-1,5-diyl group having a fluorine atom, and

    • polycyclic cycloalkanediyl groups having a fluorine atom, such as a norbornane-1,4-diyl group having a fluorine atom, a norbornane-2,5-diyl group having a fluorine atom, a 5-norbornene-2,3-diyl group having a fluorine atom, an adamantane-1,5-diyl group having a fluorine atom, and an adamantane-2,6-diyl group having a fluorine atom.


The number of fluorine atoms of the alkanediyl group and the cycloalkanediyl group each having a fluorine atom in L42f may be 1 or more, and preferably 2 or more.


The alkanediyl group and the cycloalkanediyl group each having a fluorine atom in L42f are preferably a perfluoroalkanediyl group and a perfluorocycloalkanediyl group, respectively.


Examples of the perfluoroalkanediyl group in L42f include a difluoromethylene group, a perfluoroethylene group, a perfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2-diyl group, a perfluorobutane-1,4-diyl group, a perfluorobutane-2,2-diyl group, a perfluorobutane-1,2-diyl group, a perfluoropentane-1,5-diyl group, a perfluoropentane-2,2-diyl group, a perfluoropentane-3,3-diyl group, a perfluorohexane-1,6-diyl group, a perfluorohexane-2,2-diyl group, a perfluorohexane-3,3-diyl group, a perfluoroheptane-1,7-diyl group, a perfluoroheptane-2,2-diyl group, a perfluoroheptane-3,4-diyl group, a perfluoroheptane-4,4-diyl group, a perfluorooctane-1,8-diyl group, a perfluorooctane-2,2-diyl group, a perfluorooctane-3,3-diyl group, a perfluorooctane-4,4-diyl group and the like.


Examples of the perfluorocycloalkanediyl group in L42f include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantanediyl group and the like.


L41 is preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms, more preferably a single bond, a methylene group or an ethylene group, and still more preferably a single bond or a methylene group.


L42f is preferably a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms, more preferably a perfluoroalkanediyl group having 1 to 6 carbon atoms, and still more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.


Examples of the structural unit (a4-1) include the following structural units, and structural units in which a methyl group corresponding to R41 in the structural unit (a4-1) in the following structural units is substituted with a hydrogen atom:




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Examples of the structural unit represented by formula (a4-2) include the following structural unit:




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wherein, in formula (a4-2),

    • R41 represents a hydrogen atom or a methyl group,
    • L43f represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a fluorine atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—, and
    • R43f represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a fluorine atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—,
    • in which at least one of L43f and R43f has a fluorine atom, and the upper limit of the total number of carbon atoms of L43f and R43f is 21.


Examples of the saturated hydrocarbon group in L43f and R43f include a linear or branched chain saturated hydrocarbon group and a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and groups formed by combining these groups. Examples of the saturated hydrocarbon group in L43f and R43f include groups which are the same as the saturated hydrocarbon groups mentioned as the saturated hydrocarbon group as for R42 in formula (a4) as long as the upper limit of the total number of carbon atoms of L43f and R43f permit.


The saturated hydrocarbon group as for L43f is preferably an alkanediyl group having 1 to 6 carbon atoms or a group represented by formula (L43f-1):




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wherein, in formula (L43f-1),

    • s represents 0 or 1,
    • L45f and L46f each independently represent a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a fluorine atom,
    • L47f represents a single bond or a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a fluorine atom,
    • X46f and X47f each independently represent —O—, —CO—, —CO—O— or —O—CO—,
    • in which the total number of carbon atoms of L45f, L46f, L47f, X46f and X47f is 7 or less, and
    • * and ** are bonding sites, and ** is a bonding site to —O—CO—R43f.


Examples of the divalent saturated hydrocarbon group represented by L45f, L46f and L47f in the group represented by formula (L43f-1) include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and a divalent saturated hydrocarbon group formed by combining an alkanediyl group and a divalent alicyclic saturated hydrocarbon group. Specific examples thereof include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group and the like.


S is preferably 0.


Examples of the group represented by formula (L43f-1) include the following groups. In the following, * and ** each represent a bonding site, and ** is a bonding site to —O—CO—R43f.




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R43f is preferably a saturated hydrocarbon group having a fluorine atom.


In this case, examples of the structural unit represented by formula (a4-2) include a structural unit represented by formula (a4-2A) or formula (a4-2B):




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wherein, in formula (a4-2A) and formula (a4-2B),

    • R41 and L43f are the same as defined in formula (a4-2),
    • R43fA represents a saturated hydrocarbon group having 1 to 20 carbon atoms which has a fluorine atom,
    • A43f represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—,
    • X43 represents **—O—CO— or **—CO—O—, and ** represents a bonding site to A43f, and
    • R43fB represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom,
    • in which, in formula (a4-2A), the total number of carbon atoms of L43f and R43fA is 21 or less, and in formula (a4-2B), the total number of carbon atoms of L43f, A43f, X43 and R43fB is 21 or less, and at least one of A43f and R43fB has at least one fluorine atom.


Examples of the saturated hydrocarbon group as for R43fA include the same saturated hydrocarbon groups as mentioned as for R42 in formula (a4) as long as the upper limit of the number of carbon atoms permit.


R43fA is preferably an alkyl group having 1 to 13 carbon atoms which has a fluorine atom, a cycloalkyl group having 3 to 12 carbon atoms which has a fluorine atom, or group obtained by combining these groups, and more preferably *—(CF2)n43f—R42′ (* represents a bonding site to a carbonyl group, n43f represents an integer of 1 to 6, and R42′ represents a hydrogen atom or a fluorine atom) or a perfluoro cycloalkyl group having 3 to 12 carbon atoms.


Examples of the saturated hydrocarbon group as for A43f and R43fB include the same saturated hydrocarbon groups as mentioned as for R42 in formula (a4) as long as the upper limit of the number of carbon atoms permit.


A43f is preferably a divalent chain saturated hydrocarbon group which may have a fluorine atom, a divalent alicyclic saturated hydrocarbon group, or groups obtained by combining these groups, more preferably a divalent chain saturated hydrocarbon group having a fluorine atom, and still more preferably an alkanediyl fluoride group having 1 to 6 carbon atoms.


The saturated hydrocarbon group which may have a fluorine atom as for R43fB is preferably a chain saturated hydrocarbon group, an alicyclic saturated hydrocarbon group, or groups obtained by combining these groups which may have a fluorine atom, more preferably an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or groups obtained by combining these groups which may have a fluorine atom, and still more preferably alkyl fluoride groups such as a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, a perfluorohexyl group, a heptyl group, a perfluoro heptyl group, an octyl group and a perfluorooctyl group; a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, a perfluoro cyclohexyl group, an adamantyl group, an adamantylmethyl group, an adamantyldimethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, a perfluoroadamantylmethyl group and the like.


In formula (a4-2B), an example of the structure that the group represented by *-A43f-X43—R43fB can take includes the following structures (* is a bonding site to a carbonyl group).




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Examples of the structural unit represented by formula (a4-2A) include the following structural units, and structural units in which the methyl group corresponding to R41 in the structural unit represented by formula (a4-2A) in the following structural units is substituted with a hydrogen atom.




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Examples of the structural unit represented by formula (a4-2B) include the following structural units, and structural units in which the methyl group corresponding to R41 in the structural unit represented by formula (a4-2B) in the following structural units is substituted with a hydrogen atom.




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Examples of the structural unit (a4) also include a structural unit represented by formula (a4-3):




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wherein, in formula (a4-3),

    • R41 represents a hydrogen atom or a methyl group,
    • L44f each independently represent a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a fluorine atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—, and
    • R44f each independently represent a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a fluorine atom, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—,
    • in which at least one of L44f and R44f has a fluorine atom, and the upper limit of the total number of carbon atoms of L44f and R44f is 21.


Examples of the saturated hydrocarbon group in L44f and R44f include a linear or branched chain saturated hydrocarbon group and a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and groups formed by combining these groups. Examples of the saturated hydrocarbon group in L44f and R44f include groups which are the same as saturated hydrocarbon groups as mentioned as for R42 in formula (a4) as long as the upper limit of the number of carbon atoms of L44f and R44f permit.


L44f is preferably an alkanediyl group having 1 to 14 carbon atoms (—CH2— included in the alkanediyl group may be replaced by —O— or —CO—), and more preferably a group represented by —(CH2)j1—, —(CH2)j2—O—(CH2)j3— or —(CH2)j4—CO—O—(CH2)j5— (j1 to j5 each independently represent an integer of 1 to 6 represents). It is also preferably an alkanediyl group having 1 to 4 carbon atoms (one —CH2— included in the alkanediyl group may be replaced by —O—, and one —CH2—CH2— included in the alkanediyl group may be replaced by —CO—O— or —O—CO—).


R44f is preferably a saturated hydrocarbon group having 1 to 10 carbon atoms which has a fluorine atom, more preferably an alkyl group having 1 to 10 carbon atoms which has a fluorine atom, an alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms which has a fluorine atom, or groups obtained by combining these groups, still more preferably an alkyl group having 1 to 10 carbon atoms which has a fluorine atom, and yet more preferably an alkyl group having 1 to 6 carbon atoms which has a fluorine atom.


Examples of the structural unit represented by formula (a4-3) include the following structural units, and structural units in which the methyl group corresponding to R41 in the structural unit (a4-3) is substituted with a hydrogen atom in the structural units represented by the following formulas.




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When the resin (A) includes the structural unit (a4), the content is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and still more preferably 3 to 10 mol %, based on all structural units of the resin (A).


<Structural Unit (a5)>


Examples of a non-leaving hydrocarbon group possessed by the structural unit (a5) include groups having a linear, branched or cyclic hydrocarbon group. Of these, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.


The structural unit (a5) includes, for example, a structural unit represented by formula (a5-1):




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wherein, in formula (a5-1),

    • R51 represents a hydrogen atom or a methyl group,
    • R52 represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom included in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms, and
    • L55 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH2— included in the saturated hydrocarbon group may be replaced by —O— or —CO—.


The alicyclic hydrocarbon group in R52 may be either monocyclic or polycyclic. The monocyclic alicyclic hydrocarbon group includes, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. The polycyclic alicyclic hydrocarbon group includes, for example, an adamantyl group and a norbornyl group.


The aliphatic hydrocarbon group having 1 to 8 carbon atoms includes, for example, alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group.


Examples of the alicyclic hydrocarbon group having a substituent includes a 3-methyladamantyl group and the like.


R52 is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.


Examples of the divalent saturated hydrocarbon group in L55 include a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and a divalent chain saturated hydrocarbon group is preferable.


The divalent chain saturated hydrocarbon group includes, for example, alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group and a pentanediyl group.


The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include cycloalkanediyl groups such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.


The group in which —CH2— included in the divalent saturated hydrocarbon group represented by L55 is replaced by —O— or —CO— includes, for example, groups represented by formula (L1-1) to formula (L1-4). In the following formulas, * and ** each represent a bonding site, and * represents a bonding site to an oxygen atom:




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wherein, in formula (L1-1),

    • Xx1 represents *—O—CO— or *—CO—O— (* represents a bonding site to Lx1),
    • Lx1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms,
    • Lx2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms, and the total number of carbon atoms of Lx1 and Lx2 is 16 or less:


      wherein, in formula (L1-2),
    • Lx3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms,
    • Lx4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms, and the total number of carbon atoms of Lx3 and Lx4 is 17 or less:


      wherein, in formula (L1-3),
    • Lx5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms,
    • Lx6 and Lx7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms, and
    • the total number of carbon atoms of Lx5, Lx6 and Lx7 is 15 or less:


      wherein, in formula (L1-4),
    • Lx8 and Lx9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms, and
    • Wx1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms, and
    • the total number of carbon atoms of Lx8, Lx9 and Wx1 is 15 or less.


Lx1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.


Lx2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond.


Lx3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.


Lx4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.


Lx5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.


Lx6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.


Lx7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.


Lx8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.


Lx9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.


Wx1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, and more preferably a cyclohexanediyl group or an adamantanediyl group.


The group represented by formula (L1-1) includes, for example, the following divalent groups.




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The group represented by formula (L1-2) includes, for example, the following divalent groups.




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The group represented by formula (L1-3) includes, for example, the following divalent groups.




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The group represented by formula (L1-4) includes, for example, the following divalent groups.




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L55 is preferably a single bond or a group represented by formula (L1-1).


Examples of the structural unit (a5-1) include the following structural units and structural units in which a methyl group corresponding to R51 in the structural unit (a5-1) in the following structural units is substituted with a hydrogen atom.




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When the resin (A) includes the structural unit (a5), the content is preferably 1 to 30 mol %, more preferably 2 to 20 mol %, and still more preferably 3 to 15 mol %, based on all structural units of the resin (A).


<Structural Unit (a6)>


The structural unit (a6) is a structural unit having an —SO2— group, and it is preferable to have an —SO2— group in a side chain.


The structural unit having an —SO2— group may have a linear structure having an —SO2— group, a branched structure having an —SO2— group, or a cyclic structure (monocyclic and polycyclic structure) having an —SO2— group. The structural unit is preferably a structural unit which has a cyclic structure having an —SO2— group, and more preferably a structural unit which has a cyclic structure (sultone ring) having —SO2—O—.


Examples of the sultone ring include rings represented by the following formula (T1-1), formula (T1-2), formula (T1-3) and formula (T1-4). The bonding site can be any position. The sultone ring may be monocyclic, and is preferably polycyclic. The polycyclic sultone ring means a bridged ring which has —SO2—O— as an atomic group constituting the ring, and examples thereof include rings represented by formula (T1-1) and formula (T1-2). The sultone ring may have, as the atomic group constituting the ring, a heteroatom, in addition to —SO2—O—, like the ring represented by formula (T1-2). Examples of the heteroatom include an oxygen atom, a sulfur atom or a nitrogen atom, and an oxygen atom is preferable.




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The sultone ring may have a substituent, and examples of the substituent include an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxy group, a halogen atom, a hydroxy group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms and an alkylcarbonyl group having 2 to 4 carbon atoms.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group and a decyl group, and the alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group.


Examples of the alkyl group having a halogen atom include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group and a triiodomethyl group, and a trifluoromethyl group is preferable.


Examples of the alkyl group having a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a 2-hydroxyethyl group.


Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.


Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a tolyl group, a xylyl group, a cumyl group, a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.


Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.


Examples of the alkoxycarbonyl group include groups in which an alkoxy group is bonded with a carbonyl group, such as a methoxycarbonyl group or an ethoxycarbonyl group, and preferably include an alkoxycarbonyl group having 6 or less carbon atoms and more preferably include a methoxycarbonyl group.


Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.


From the viewpoint that it is easy to produce a monomer from which the structural unit (a6) is derived, a sultone ring having no substituent is preferable.


The sultone ring is preferably a ring represented by the following formula (T1′):




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wherein, in formula (T1′),

    • X11 represents an oxygen atom, a sulfur atom or a methylene group,
    • R41 represents an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxy group, a halogen atom, a hydroxy group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, or an alkylcarbonyl group having 2 to 4 carbon atoms,
    • ma represents an integer of 0 to 9, and when ma is 2 or more, a plurality of R41 may be the same or different, and
    • the bonding site may be any position.
    • X11 is preferably an oxygen atom or a methylene group, and more preferably a methylene group.


Examples of R41 include those which are the same as the substituent of the sultone ring mentioned above, and an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxy group is preferable.


ma is preferably 0 or 1, and more preferably 0.


Examples of the ring represented by formula (T1′) include the following rings. The bonding site may be any position. Particularly, the bonding site is preferably the 1-position or the 3-position.




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It is preferable that the structural unit having an —SO2— group further has a group derived from a polymerizable group. Examples of the polymerizable group include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, an acryloylthio group, a methacryloylthio group and the like.


Particularly, the monomer from which the structural unit (a6) is derived is preferably a monomer having an ethylenically unsaturated bond, and more preferably a (meth)acrylic monomer.


The structural unit (a6) is preferably a structural unit represented by formula (a6-0):




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wherein, in formula (a6-0),

    • Rx represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom,
    • Axx represents an oxygen atom, —N(Rc)— or a sulfur atom,
    • Ax represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH2— included in the saturated hydrocarbon group may be replaced by —O—, —CO— or —N(Rd)—,
    • X11 represents an oxygen atom, a sulfur atom or a methylene group,
    • R41 represents a halogen atom or an alkyl group having 1 to 12 carbon atoms which may have a hydroxy group, a halogen atom, a hydroxy group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, or an alkylcarbonyl group having 2 to 4 carbon atoms,
    • ma represents an integer of 0 to 9, and when ma is 2 or more, a plurality of R41 may be the same or different from each other, and
    • Rc and Rd each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.


Examples of the halogen atom as for Rx include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the alkyl group as for Rx include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexyl group, and an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group or an ethyl group is more preferable.


Examples of the alkyl group having a halogen atom as for Rx include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group and a triiodomethyl group.


Rx is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group.


Examples of the divalent saturated hydrocarbon group as for Ax include a linear alkanediyl group, a branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and the divalent saturated hydrocarbon group may be those obtained by combining two or more of these groups.


Specific examples thereof include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, a heptadecane-1,17-diyl group, an ethane-1,1-diyl group, a propane-1,1-diyl group and a propane-2,2-diyl group;

    • branched alkanediyl groups such as a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group;
    • monocyclic divalent alicyclic saturated hydrocarbon groups which are cycloalkanediyl groups such as a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and a cyclooctane-1,5-diyl group; and
    • polycyclic divalent alicyclic saturated hydrocarbon groups such as a norbornane-1,4-diyl group, a norbornane-2,5-diyl group, an adamantane-1,5-diyl group and an adamantane-2,6-diyl group.


The bonding site to the sultone ring as for Ax can be any position and is preferably the 1-position.


Examples of the structural unit (a6-0) include the following structural units.




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Of these, structural units represented by formula (a6-1), formula (a6-2), formula (a6-6), formula (a6-7), formula (a6-8) and formula (a6-12) are preferable, and structural units represented by formula (a6-1), formula (a6-2), formula (a6-7) and (a6-8) are more preferable.


When the resin (A) includes the structural unit (a6), the content is preferably 1 to 50 mol %, more preferably 2 to 40 mol %, and still more preferably 3 to 30 mol %, based on all structural units of the resin (A).


<Structural Unit (a7)>


The resin may further include a structural unit which is decomposed upon exposure to radiation to generate an acid (hereinafter sometimes referred to as “structural unit (a7)”). Specific examples of the structural unit (a7) include the structural units mentioned in JP 2016-79235 A, and a structural unit having a sulfonate group or a carboxylate group and an organic cation in a side chain or a structural unit having a sulfonio group and an organic anion in a side chain are preferable.


The structural unit having a sulfonate group or a carboxylate group and an organic cation in a side chain is preferably a structural unit represented by formula (a7-A):




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wherein, in formula (a7-A),

    • Ra7 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Xa71 represents a single bond, *—O—**, *—CO—O—**, *—O—CO—O—**, *—CO—NRa71-**, *—NRa71—CO—O—**, *—O—CO—NRa71—** or *-Ax-Ph-Ay-**,
    • Ra71 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
    • Ph represents a phenylene group which may have a substituent,
    • Ax and Ay each independently represent one bond species selected from the group consisting of a single bond, an ether bond, a thioether bond, an ester bond, an amide bond and a carbonic acid ester bond,
    • * and ** represent a bonding site, and * represent a bonding site to carbon atoms to which Ra7 is bonded,
    • La71 and La72 each independently represent a hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and —CH2— included in the hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—,
    • Xa72 represents ***—CO—O—, ***—O—CO—, ***—O—CO—O—, ***—O—, and *** represents a bonding site to La71,
    • na7 represents an integer of 0 to 2, and when na7 is 2, a plurality of groups in parentheses may be the same or different from each other,
    • RA represents a sulfonate anion or a carboxyl anion, and
    • ZA+ represents an organic cation.


Examples of the alkyl group having 1 to 6 carbon atoms in Ra7 and Ra71 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group.


Examples of the halogen atom in Ra7 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.


Examples of the alkyl group having 1 to 6 carbon atoms which has a halogen atom in Ra7 include a trifluoromethyl group, a difluoromethyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a dichloromethyl group, a triiodomethyl group, a diiodo methyl group, a tribromomethyl group, a dibromo methyl group and the like.


Ra7 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, still more preferably a hydrogen atom, a methyl group or an ethyl group, and yet more preferably a hydrogen atom or a methyl group.


When Xa71 is a group represented by *-Ax-Ph-Ay-**, preferred is a linking group represented by the following formula (X10)




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wherein, in formula (X10),

    • Ax represents bond species bonded to carbon atoms to which Ra7 is bonded, and represents one bond species selected from the group consisting of a single bond, an ether bond, a thioether bond, an ester bond, a carbonic acid ester bond and an amide bond,
    • Ay represents bond species to which La71 is bonded, and represents one bond species selected from the group consisting of a single bond, an ether bond, a thioether bond, an ester bond, a carbonic acid ester bond and an amide bond,
    • Rx represents a halogen atom, a hydroxy group, an alkyl fluoride group having 1 to 6 carbon atoms, an alkyl group having 1 to 18 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and
    • mx represents an integer of 0 to 4, and when mx is an integer of 2 or more, a plurality of Rx may be the same or different from each other.


When one of Ax and Ay is a single bond, the other is preferably one selected from the group consisting of an ether bond, a thioether bond, an ester bond, a carbonic acid ester bond and an amide bond


When either Ax or Ay is an amide bond, a bond represented by —CO—NRa71— is preferable.


The bonding site of Ay in the phenylene group is preferably the m-position or the p-position, and more preferably the p-position, with respect to the bonding site of Ax.


Particularly, Rx is preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a methyl group or an ethyl group,

    • mx is preferably 0, 1 or 2.


Examples of Xa71 include a single bond and groups represented by the following formula (X10-1) to formula (X10-10). * represents a bonding site to carbon atoms to which —Ra7 is bonded. ** represents a bonding site to La71. X20 represents —O— or —NRa7—.




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Specific examples of the groups represented by formula (X10-1) to formula (X10-10) include the following groups.




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Particularly, Xa71 is preferably a single bond and a group represented by any one of formula (X10-1′) and formula (X10-3′) to formula (X10-9′), more preferably a single bond or a group represented by any one of formula (X10-1′), formula (X10-4′), formula (X10-5′), formula (X10-6′) and formula (X10-9′), and still more preferably a single bond, a group represented by formula (X10-1′), a group represented by formula (X10-5′) or a group represented by formula (X10-6′) or formula (X10-9′).


Examples of the hydrocarbon group as for La71 include groups which are obtained by removing one hydrogen atom from a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining two or more of these groups, and bonding to Xa71 and Xa72. Examples of the hydrocarbon group as for La72 include groups which are obtained by removing one hydrogen atom from a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining two or more of these groups, and bonding to Xa71 and RA.


Examples of the chain hydrocarbon group as for La71 and La72 include groups obtained by removing one hydrogen atom of an alkyl group or an alkenyl group. The alkyl group may be either linear or branched, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentanedecyl group, a heptadecyl group and the like. Examples of the alkenyl group include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, an isooctenyl group, a nonenyl group and the like.


The number of carbon atoms of the chain hydrocarbon group is preferably 1 to 20, more preferably 1 to 18, still more preferably 1 to 10 carbon atoms.


Examples of the alicyclic hydrocarbon group as for La71 and La72 include groups obtained by removing one hydrogen atom of a monocyclic or polycyclic cycloalkyl group. Examples of the monocyclic cycloalkyl group include a cyclobutyl group, a cycloheptyl group, a cyclohexyl group, a cyclopentyl group, a cyclooctyl group and the like.


Examples of the polycyclic cycloalkyl group as for La71 and La72 include a cycloalkyl group having a crosslinked structure, a cycloalkyl group in which two or more rings are fused, or a cycloalkyl group in which two rings are bonded by spiro bonding. Examples of the cycloalkyl group having a crosslinked structure include a norbornyl group, an adamantyl group and the like. Examples of the cycloalkyl group in which two or more rings are fused include a bicyclo[4,4,0]decane group, a steroid group (steroid skeleton) and the like. Examples of the cycloalkyl group in which two rings are bonded by spiro bonding include a spirocyclic cycloalkyl group in which one cycloalkyl group selected from the group consisting of a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group, and a cycloalkyl group having 5 to 8 carbon atoms are bonded by spiro bonding, and the like. A double bond may be formed between two carbon atoms included in the alicyclic hydrocarbon group. More specifically, alicyclic hydrocarbon groups represented by the following formulas are exemplified.




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When the alicyclic hydrocarbon group is a monocyclic cycloalkyl group, the number of carbon atoms of the alicyclic hydrocarbon group is preferably 3 to 18, more preferably 3 to 12, and still more preferably 3 to 8. When the alicyclic hydrocarbon group is a polycyclic cycloalkyl group, the number of carbon atoms of the alicyclic hydrocarbon group is preferably 6 to 18, and more preferably 7 to 12.


Examples of the aromatic hydrocarbon group La7′ and La72 include groups obtained by removing one hydrogen atom of an aryl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a fluorenyl group and the like. The number of carbon atoms of the aromatic hydrocarbon group is preferably 5 to 14, more preferably 6 to 14, and still more preferably 6 to 10.


When —CH2— included in the hydrocarbon group as for La7′ and La72 is replaced by —O—, —CO—, —S— or —SO2—, the number of carbon atoms before replacement is taken as the total number of the hydrocarbon group.


Of the hydrocarbon groups as for La7′ and La72, examples of the group in which —CH2— included in the chain hydrocarbon group is replaced by —O—, —CO—, —S— or —SO2— include a hydroxy group (a group in which —CH2— included in the methyl group is replaced by —O—), a carboxy group (a group in which —CH2—CH2— included in the ethyl group is replaced by —O—CO—), a thiol group (a group in which —CH2— included in the methyl group is replaced by —S—), a carbonyl group (a group in which —CH2— included in the methylene group is replaced by —CO—), an oxy group (a group in which —CH2— included in the methylene group is replaced by —O—), a thio group (a group in which —CH2— included in the methylene group is replaced by —S—), a sulfonyl group (a group in which —CH2— included in the methylene group is replaced by —SO2—), an alkoxy group (a group in which —CH2— at any position included in the alkyl group is replaced by —O—), an alkoxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —O—CO—), an alkylcarbonyl group (a group in which —CH2— at any position included in the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkyl group is replaced by —CO—O—), an alkanediyloxy group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —O—), an alkanediyloxycarbonyl group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (a group in which —CH2— at any position included in the alkanediyl group is replaced by —CO—), an alkanediylcarbonyloxy group (a group in which —CH2—CH2— at any position included in the alkanediyl group is replaced by —CO—O—) and the like. Examples of these replaced groups include the same groups as mentioned herein as long as the upper limit of the number of carbon atoms permits.


Of the hydrocarbon groups as for La71 and La72, examples of the group in which —CH2— included in the alicyclic hydrocarbon group is replaced by —O—, —CO—, —S— or —SO2— include groups having a structure such as cyclic ether, cyclic ketone, cyclic ester (lactone), cyclic thioether, cyclic acetal or cyclic sulfonic acid ester (sultone). Specific examples thereof include alicyclic hydrocarbon groups represented by the following formulas. The bonding site of the alicyclic hydrocarbon group represented by the following formulas can be any position.




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Of the hydrocarbon groups as for La71 and La72, —CH2— included in the aromatic hydrocarbon group may be replaced by —O— or —S—, and examples of the group in which —CH2— is replaced by —O— or —S— include groups derived from a furan ring or a thiophene ring, respectively.


Examples of the groups obtained by combining two or more groups of the chain hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group as for La71 and La72 include a group obtained by combining the chain hydrocarbon group with the alicyclic hydrocarbon group, a group obtained by combining the chain hydrocarbon group with the aromatic hydrocarbon group, a group obtained by combining the alicyclic hydrocarbon group with the aromatic hydrocarbon group, a group obtained by combining the chain hydrocarbon group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group. The group obtained by combining the alicyclic hydrocarbon group with the aromatic hydrocarbon group may also be a fused ring.


Examples of the substituent which may be possessed by the hydrocarbon group as for La71 and La72 include a halogen atom, a cyano group and a nitro group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.


When La71 and La72 are groups obtained by combining an alicyclic hydrocarbon group or an aromatic hydrocarbon group with a chain hydrocarbon group, the chain hydrocarbon group may be substantially regarded as a substituent which is possessed by the alicyclic hydrocarbon group or the aromatic hydrocarbon group. By replacing —CH2— of the chain hydrocarbon group included in the hydrocarbon group by —O—, —CO—, —S— or —SO2— as for La71 and La72, the hydrocarbon group as for La71 and La72 can substantially have a substituent such as a hydroxy group, a carboxy group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a thiol group or a sulfonyl group.


na7 is preferably 0 or 1.


Examples of ZA+ in formula (a7-A) include the same cations as in the salt represented by formula (B1) or the like.


In formula (a7-A), when the hydrocarbon group as for La71 and La72 is a saturated hydrocarbon group, it is possible to include the same groups as mentioned as divalent linking group as for Ab7 in formula (a7-B) mentioned below.


Examples of the structural unit represented by formula (a7-A) also include a structural unit or the like represented by formula (a7-A1):




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wherein, in formula (a7-A1),

    • Ra7, Xa71, La71, Xa72, na7, RA and ZA+ are the same as defined above,
    • z7 represents an integer of 0 to 6, and
    • Qa7, Qb7, Rz71 and Rz72 each independently represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms, and when z7 is 2 or more, a plurality of Rz71 and Rz72 may be the same or different from each other.


Examples of the perfluoroalkyl group having 1 to 6 carbon atoms or alkyl group having 1 to 6 carbon atoms in Qa7, Qb7, Rz71 and Rz72 include the same groups as mentioned as for Ra7.


Examples of the structural unit represented by formula (a7-A) include the following structural units, structural units in which the group corresponding to the methyl group as for Ra7 is substituted with a hydrogen atom, a halogen atom (e.g., a fluorine atom) or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom (e.g., a trifluoromethyl group, etc.), and structural units mentioned in WO 2012/050015 A. ZA+ represents an organic cation.




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The structural unit having a sulfonio group and an organic anion in the side chain is preferably a structural unit represented by formula (a7-B):




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wherein, in formula (a7-B),

    • Ra7 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom,
    • Ab7 represents a single bond or a divalent linking group,
    • Rb71 represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent,
    • Rb72 and Rb73 each independently represent a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, Rb72 and Rb73 may be bonded to each other to form a ring together with sulfur atoms to which Rb72 and Rb73 are bonded, and
    • A represents an organic anion.


Examples of the halogen atom and the alkyl group which may have a halogen atom as for Ra7 include the same halogen atoms and the alkyl groups which may have a halogen atom of formula (a7-A).


Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by Rb71 include a phenylene group and a naphthylene group.


Examples of the hydrocarbon group represented by Rb72 and Rb73 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups formed by combining these groups.


Examples of the alkyl group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, and the groups formed by combining these groups include the same groups as mentioned above.


Examples of the divalent linking group represented by Ab7 include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH2— included in the divalent saturated hydrocarbon group may be replaced by —O—, —S— or —CO—.


Examples of the divalent saturated hydrocarbon group include divalent chain saturated hydrocarbon groups such as a linear or branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, or a combination thereof.


Specific examples thereof include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group and a dodecane-1,12-diyl group; branched alkanediyl groups such as a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group; divalent monocyclic alicyclic saturated hydrocarbon groups which are monocyclic cycloalkanediyl groups, such as a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and a cyclooctane-1,5-diyl group; and divalent polycyclic alicyclic saturated hydrocarbon groups which are polycyclic cycloalkanediyl groups, such as a norbornane-1,4-diyl group, a norbornane-2,5-diyl group, an adamantane-1,5-diyl group and an adamantane-2,6-diyl group.


Those in which —CH2— included in the saturated hydrocarbon group are replaced by —O—, —S— or —CO— include, for example, the following divalent groups. Before replacing —CH2— included in the saturated hydrocarbon group by —O—, —S— or —CO—, the number of carbon atoms is 17 or less. In the following formulas, * and ** represent a bonding site, and * represents a bonding site to Rb71.




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X3 represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms.


X4 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.


X5 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.


X6 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.


X7 represents a trivalent saturated hydrocarbon group having 1 to 14 carbon atoms.


X8 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.


Examples of the structural unit including a cation in formula (a7-B) include the following structural units and structural units in which a group corresponding to a methyl group of Ra7 is substituted with a hydrogen atom, a halogen atom (e.g., a fluorine atom, etc.) or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom (e.g., a trifluoromethyl group, etc.) and the like.




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Examples of the organic anion represented by A include a sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion and a carboxylic acid anion. The organic anion represented by A is preferably a sulfonic acid anion. The sulfonic acid anion is more preferably those which are the same as anions mentioned in the compound (B). Examples of the sulfonic acid anion, the sulfonylimide anion, the sulfonylmethide anion and the carboxylic acid anion include those which are the same as anions mentioned in the compound (B).


Examples of the structural unit represented by formula (a7-B) include the followings.




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When the resin (A) includes a structural unit (a7), the structural unit (a7) may be included alone, or two or more structural units may be included. The total content of the structural unit (a7) is preferably 1 to 30 mol %, more preferably 1 to 25 mol %, still more preferably 2 to 20 mol %, yet more preferably still more preferably 3 to 15 mol %, and further preferably 3 to 10 mol %, based on all structural units of the resin (A).


The resin (A) may include a structural unit other than the above-mentioned structural units, and examples of such structural unit include structural units known in the relevant technical field.


The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).


The structural unit (a1) is preferably at least one selected from the group consisting of a structural unit (a1-0), a structural unit (a1-1), a structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group), a structural unit (a1-4), a structural unit (a1-5) and a structural unit (a1-6), more preferably at least two, and still more preferably at least two selected from the group consisting of a structural unit (a1-1) and a structural unit (a1-2).


The structural unit (s) is preferably at least one selected from the group consisting of a structural unit (a2) and a structural unit (a3). The structural unit (a2) is preferably a structural unit (a2-C) or a structural unit (a2-A). The structural unit (a3) is preferably at least one selected from the group consisting of a structural unit represented by formula (a3-1), a structural unit represented by formula (a3-2) and a structural unit represented by formula (a3-4).


The resin (A) is preferably a resin including a structural unit (a1) and a structural unit (a2) or a resin including a structural unit (a1) and a structural unit (a3), more preferably a resin including a structural unit (a1) and a structural unit (a2-A) or a resin including a structural unit (a1) and at least one selected from the group consisting of a structural unit (a3-1), a structural unit (a3-2), a structural unit (a3-3) and a structural unit (a3-4), still more preferably a resin including a structural unit (a1), a structural unit (a2-A) and at least one selected from the group consisting of a structural unit (a3-1), a structural unit (a3-2), a structural unit (a3-3) and a structural unit (a3-4), and yet more preferably a resin including a structural unit (a1), a structural unit (a2-A) and a structural unit (a3-4).


The respective structural units constituting the resin (A) may be used alone, or two or more structural units may be used in combination. Using a monomer from which these structural units are derived, it is possible to produce by a known polymerization method (e.g. radical polymerization method). The content of the respective structural units included in the resin (A) can be adjusted according to the amount of the monomer used in the polymerization.


The weight-average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, and still more preferably 3,000 or more), and 50,000 or less (more preferably 30,000 or less, and still more preferably 15,000 or less), and an oligomer having a weight-average molecular weight of less than the above value may be included. As used herein, the weight-average molecular weight is a value determined by gel permeation chromatography under the analysis conditions mentioned in Examples.


<Resin Other than Resin (A)>


In the resist composition of the present invention, the resin other than the resin (A) may be used in combination.


The resin other than the resin (A) includes, for example, a resin including the same structural unit as that of the resin (A) except for including no structural unit (a1) in the resin (A) (hereinafter sometimes referred to as resin (AX))), a resin including a structural unit (a4) and/or a structural unit (a5) (hereinafter sometimes referred to as resin (X)).


The resin (AX) includes a resin including a structural unit (a2), and preferably includes a structural unit (a2-A). In the resin (AX), the content of the structural unit (a2-A) is preferably 5 to 80 mol %, and more preferably 10 to 70 mol %, based on the total of all structural units of the resin (AX).


Particularly, the resin (X) is preferably a resin including a structural unit (a4).


Examples of the structural unit, which may be further included in the resin (X), include a structural unit (a2), a structural unit (a3) and structural units derived from other known monomers. Particularly, the resin (X) is preferably a resin composed only of a structural unit (a4) and/or a structural unit (a5).


When the resin (X) includes a structural unit (a4), the content of the structural unit (a4) in the resin (X) is usually 20 mol % or more, preferably 30 mol % or more, more preferably 40 mol % or more, and still more preferably 45 mol % or more, based on all structural units of the resin (X). The content is also usually 100 mol % or less, preferably 80 mol % or less, more preferably 70 mol % or less, still more preferably 60 mol % or less, and yet more preferably 55 mol % or less, based on all structural units of the resin (X). Specifically, the content is usually 20 to 100 mol %, preferably 20 to 80 mol %, more preferably 30 to 70 mol %, still more preferably 40 to 60 mol %, and yet more preferably 45 to 55 mol %, based on all structural units of the resin (X). When the resin (X) includes a structural unit (a5), the content of the structural unit (a5) is usually 20 mol % or more, preferably 30 mol % or more, more preferably 40 mol % or more, and still more preferably 45 mol % or more, based on all structural units of the resin (X). The content is also usually 100 mol % or less, preferably 80 mol % or less, more preferably 70 mol % or less, still more preferably 60 mol % or less, and yet more preferably 55 mol % or less, based on all structural units of the resin (X). Specifically, the content is usually 20 to 100 mol %, preferably 20 to 80 mol %, more preferably 30 to 70 mol %, still more preferably 40 to 60 mol %, and yet more preferably 45 to 55 mol %, based on all structural units of the resin (X). When the resin (X) includes a structural unit (a4) and a structural unit (a5), the total content of the structural unit (a4) and the structural unit (a5) is usually 40 mol % or more, preferably 60 mol % or more, more preferably 70 mol % or more, and still more preferably 80 mol % or more, based on all structural units of the resin (X). The total content is also usually 100 mol % or less, based on all structural units of the resin (X). Specifically, the total content is also usually 40 to 100 mol %, preferably 60 to 100 mol %, more preferably 70 to 100 mol %, and still more preferably 80 to 100 mol %, based on all structural units of the resin (X). The structural unit (a4):structural unit (a5) is usually 0:100 to 100:0, preferably 10:90 to 90:10, and more preferably 30:70 to 70:30 or 40:60 to 60:40.


The respective structural unit constituting the resin (AX) and the resin (X) may be used alone, or two or more structural units may be used in combination. Using a monomer from which these structural units are derived, it is possible to produce by a known polymerization method (e.g. radical polymerization method). The content of the respective structural units included in the resin (AX) and the resin (X) can be adjusted according to the amount of the monomer used in the polymerization.


The weight-average molecular weight of the resin (AX) is the same as that of the resin (A).


The weight-average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less), and an oligomer having a weight-average molecular weight of less than 6,000 may be included. The measurement means of the weight-average molecular weight of the resin (X) is the same as in the case of the resin (A).


When the resist composition of the present invention includes the resin (X), the content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, still more preferably 1 to 40 parts by mass, yet more preferably 1 to 30 parts by mass, and further preferably 1 to 8 parts by mass, based on 100 parts by mass of the resin (A) and/or the resin (AX).


When the resist composition includes a resin (A), the content of the resin (A) in the resist composition is preferably 80% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 99% by mass or less, based on the solid component of the resist composition. When including resins other than the resin (A), the total content of the resin (A) and/or resins other than the resin (A) is preferably 80% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 99% by mass or less, based on the solid component of the resist composition. The solid content of the resist composition and the content of the resin thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.


<Solvent (E)>

The content of the solvent (E) in the resist composition is usually 90% by mass or more and 99.9% by mass or less, preferably 92% by mass or more and 99% by mass or less, and more preferably 94% by mass or more and 99% by mass or less. The content of the solvent (E) can be measured, for example, by a known analysis means such as liquid chromatography or gas chromatography.


Examples of the solvent (E) include glycol ether esters such as ethylcellosolve acetate, methylcellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; and cyclic esters such as γ-butyrolactone. The solvent (E) may be used alone, or two or more solvents may be used.


<Quencher (C)>

Examples of the quencher (C) include a basic nitrogen-containing organic compound, and a salt generating an acid having an acidity lower than that of an acid generated from an acid generator (salt (I) or compound (B)). When the resist composition includes the quencher (C), the content of the quencher (C) is preferably about 0.01 to 15% by mass, more preferably about 0.01 to 10% by mass, still more preferably about 0.1 to 8% by mass, and yet more preferably about 0.1 to 7% by mass, based on the amount of the solid component of the resist composition.


Examples of the basic nitrogen-containing organic compound include amine and an ammonium salt. Examples of the amine include an aliphatic amine and an aromatic amine. Examples of the aliphatic amine include a primary amine, a secondary amine and a tertiary amine.


Examples of the amine include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, 2,2′-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane, 1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene, 1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane, di(2-pyridyl)ketone, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipicolylamine, bipyridine and the like, preferably diisopropylaniline, and more preferably 2,6-diisopropylaniline.


Examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate and choline.


The acidity in a salt generating an acid having an acidity lower than that of an acid generated from the acid generator is indicated by the acid dissociation constant (pKa). Regarding the salt generating an acid having an acidity lower than that of an acid generated from the acid generator, the acid dissociation constant of an acid generated from the salt usually meets the following inequality: −3<pKa, preferably −1<pKa<7, and more preferably 0<pKa<5.


Examples of the salt generating an acid having an acidity lower than that of an acid generated from the acid generator include salts represented by the following formulas, a salt represented by formula (D) mentioned in JP 2015-147926 A (hereinafter sometimes referred to as “weak acid inner salt (D)”, and salts mentioned in JP 2012-229206 A, JP 2012-6908 A, JP 2012-72109 A, JP 2011-39502 A and JP 2011-191745 A. The salt generating an acid having an acidity lower than that of an acid generated from the acid generator is preferably a salt generating a carboxylic acid having an acidity lower than that of an acid generated from the acid generator (salt having a carboxylic acid anion), more preferably a weak acid inner salt (D), and still more preferably a diphenyliodonium salt containing a phenyl group substituted with a carboxylic acid anion among the weak acid inner salt (D).




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Examples of the weak acid inner salt (D) is preferably a diphenyliodonium salt having an iodonium cation to which two phenyl groups are bonded, and a carboxylic acid anion substituted with at least one phenyl group of two phenyl groups bonded to the iodonium cation, and specific examples thereof include a salt represented by the following formula:




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wherein, in formula (D),

    • RD1 and RD2 each independently represent a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, a nitro group or a halogen atom, and
    • m′ and n′ each independently represent an integer of 0 to 4, and when m′ is 2 or more, a plurality of RD1 may be the same or different, and when n′ is 2 or more, a plurality of RD2 may be the same or different.


Examples of the hydrocarbon group as for RD1 and RD2 include a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and groups formed by combining these groups.


Examples of the chain hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a nonyl group and the like.


The alicyclic hydrocarbon group may be either monocyclic or polycyclic, or may be either saturated or unsaturated. Examples thereof include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclononyl group and a cyclododecyl group, a norbornyl group, an adamantyl group and the like.


Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a 4-propylphenyl group, a 4-isopropylphenyl group, a 4-butylphenyl group, a 4-t-butylphenyl group, a 4-hexylphenyl group, a 4-cyclohexylphenyl group, an anthryl group, a p-adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.


Examples of the groups formed by combining these groups include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, an aralkyl group (e.g., a phenylmethyl group, a 1-phenylethyl group, a 2-phenylethyl group, a 1-phenyl-1-propyl group, a 1-phenyl-2-propyl group, a 2-phenyl-2-propyl group, a 3-phenyl-1-propyl group, a 4-phenyl-1-butyl group, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, etc.) and the like.


Examples of the alkoxy group include a methoxy group, an ethoxy group and the like.


Examples of the acyl group include an acetyl group, a propanoyl group, a benzoyl group, a cyclohexanecarbonyl group and the like.


Examples of the acyloxy group include groups obtained by bonding an oxy group (—O—) to the above acyl group.


Examples of the alkoxycarbonyl group include groups obtained by bonding a carbonyl group (—CO—) to the above alkoxy group.


Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and the like.


Preferably, RD1 and RD2 each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group or a halogen atom.


Preferably, m′ and n′ are each independently an integer of 0 to 2, and more preferably 0, and when m′ is 2 or more, a plurality of RD1 may be the same or different, and when n′ is 2 or more, a plurality of RD2 may be the same or different.


More specifically, the following salts are exemplified.




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<Other Components>

The resist composition of the present invention may also include components other than the components mentioned above (hereinafter sometimes referred to as “other components (F)”). The other components (F) are not particularly limited and it is possible to use various additives known in the resist field, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers and dyes.


<Preparation of Resist Composition>

The resist composition of the present invention can be prepared by mixing a salt (I), and if necessary, a compound (B), a resin (A), resins other than the resin (A), a solvent (E), a quencher (C) and other components (F). The order of mixing these components is any order and is not particularly limited. It is possible to select, as the temperature during mixing, appropriate temperature from 10 to 40° C., according to the type of the resin, the solubility in the solvent (E) of the resin and the like. It is possible to select, as the mixing time, appropriate time from 0.5 to 24 hours according to the mixing temperature. The mixing means is not particularly limited and it is possible to use mixing with stirring.


After mixing the respective components, the mixture is preferably filtered through a filter having a pore diameter of about 0.003 to 0.2 μm.


<Method for Producing Resist Pattern>

The method for producing a resist pattern of the present invention include:

    • (1) a step of applying the resist composition of the present invention on a substrate,
    • (2) a step of drying the applied composition to form a composition layer,
    • (3) a step of exposing the composition layer,
    • (4) a step of heating the exposed composition layer, and
    • (5) a step of developing the heated composition layer.


The resist composition can be usually applied on a substrate using a conventionally used apparatus, such as a spin coater. Examples of the substrate include inorganic substrates such as a silicon wafer, and organic substrates and the like in which a resist film or the like is formed on the surface. Before applying the resist composition, the substrate may be washed, and an organic antireflection film may be formed on the substrate.


The solvent is removed by drying the applied composition to form a composition layer. Drying is performed by evaporating the solvent using a heating device such as a hot plate (so-called “prebake”), or a decompression device. The heating temperature is preferably 50 to 200° C. and the heating time is preferably 10 to 180 seconds. The pressure during drying under reduced pressure is preferably about 1 to 1.0×105 Pa.


The composition layer thus obtained is usually exposed using an aligner. The aligner may be a liquid immersion aligner. It is possible to use, as an exposure source, various exposure sources, for example, exposure sources capable of emitting laser beam in an ultraviolet region such as KrF excimer laser (wavelength of 248 nm), ArF excimer laser (wavelength of 193 nm) and F2 excimer laser (wavelength of 157 nm), an exposure source capable of emitting harmonic laser beam in a far-ultraviolet or vacuum ultra violet region by wavelength-converting laser beam from a solid-state laser source (YAG or semiconductor laser), an exposure source capable of emitting electron beam or extreme ultraviolet light (EUV) and the like. As used herein, such exposure to radiation is sometimes collectively referred to as “exposure”. The exposure is usually performed through a mask corresponding to a pattern to be required. When electron beam is used as the exposure source, exposure may be performed by direct writing without using the mask.


The exposed composition layer is subjected to a heat treatment (so-called “post-exposure bake”) to promote the deprotection reaction in an acid-labile group. The heating temperature is usually about 50 to 200° C., and preferably about 70 to 150° C. It is also possible to perform a chemical treatment (silylation) which adjusts the hydrophilicity or hydrophobicity of the resin on a surface side of the composition after heating. Before performing the development, the steps of application of the resist composition, drying, exposure and heating may be repeatedly performed on the exposed composition layer.


The heated composition layer is usually developed with a developing solution using a development apparatus. Examples of the developing method include a dipping method, a paddle method, a spraying method, a dynamic dispensing method and the like. The developing temperature is preferably, for example, 5 to 60° C. and the developing time is preferably, for example, 5 to 300 seconds. It is possible to produce a positive resist pattern or negative resist pattern by selecting the type of the developing solution as follows.


When the positive resist pattern is produced from the resist composition of the present invention, an alkaline developing solution is used as the developing solution. The alkaline developing solution may be various aqueous alkaline solutions used in this field. Examples thereof include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline). The surfactant may be contained in the alkaline developing solution.


It is preferable that the developed resist pattern is washed with ultrapure water and then water remaining on the substrate and the pattern is removed.


When the negative resist pattern is produced from the resist composition of the present invention, a developing solution containing an organic solvent (hereinafter sometimes referred to as “organic developing solution”) is used as the developing solution.


Examples of the organic solvent contained in the organic developing solution include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycol ether solvents such as propylene glycol monomethyl ether; amide solvents such as N,N-dimethylacetamide; and aromatic hydrocarbon solvents such as anisole.


The content of the organic solvent in the organic developing solution is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably the organic developing solution is substantially composed of the organic solvent.


Particularly, the organic developing solution is preferably a developing solution containing butyl acetate and/or 2-heptanone. The total content of butyl acetate and 2-heptanone in the organic developing solution is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and still more preferably the organic developing solution is substantially composed of butyl acetate and/or 2-heptanone.


The surfactant may be contained in the organic developing solution. A trace amount of water may be contained in the organic developing solution.


During development, the development may be stopped by replacing by a solvent with the type different from that of the organic developing solution.


The developed resist pattern is preferably washed with a rinsing solution. The rinsing solution is not particularly limited as long as it does not dissolve the resist pattern, and it is possible to use a solution containing an ordinary organic solvent which is preferably an alcohol solvent or an ester solvent.


After washing, the rinsing solution remaining on the substrate and the pattern is preferably removed.


<Applications>

The resist composition of the present invention is suitable as a resist composition for exposure of KrF excimer laser, a resist composition for exposure of ArF excimer laser, a resist composition for exposure of electron beam (EB) or a resist composition for exposure of EUV, particularly a resist composition for exposure of electron beam (EB) or a resist composition for exposure of EUV, and the resist composition is useful for fine processing of semiconductors.


EXAMPLES

The present invention will be described more specifically by way of Examples. Percentages and parts expressing the contents or amounts used in the Examples are by mass unless otherwise specified.


The weight-average molecular weight is a value determined by gel permeation chromatography. Analysis conditions of gel permeation chromatography are as follows.

    • Column: TSKgel Multipore HXL-M×3+guardcolumn (manufactured by TOSOH CORPORATION)
    • Eluent: tetrahydrofuran
    • Flow rate: 1.0 mL/min
    • Detector: RI detector
    • Column temperature: 40° C.
    • Injection amount: 100 μl
    • Molecular weight standards: polystyrene standard (manufactured by TOSOH CORPORATION)


Structures of compounds were confirmed by measuring a molecular ion peak using mass spectrometry (LC: Model 1100, manufactured by Agilent Technologies, Inc., and MASS: Model LC/MSD, manufactured by Agilent Technologies, Inc.). The value of this molecular ion peak in the following Examples is indicated by “MASS”.


Example 1: Synthesis of Salt Represented by Formula (I-8)



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4.04 Parts of a compound represented by formula (I-8-a), 3.70 parts of a compound represented by formula (I-8-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated, and then 3 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 7.24 parts of a salt represented by formula (I-8-c). 5.00 Parts of the resulting salt represented by formula (I-8-c) and 10 parts of methanol were mixed, and after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 4.12 parts of a salt represented by formula (I-8-c′).




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3.75 Parts of a salt represented by formula (I-8-c′), 6.41 parts of a salt represented by formula (I-8-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 7.22 parts of a salt represented by formula (I-8).


MASS (ESI (+) Spectrum): M+ 339.1


MASS (ESI (−) Spectrum): M517.1


Example 2: Synthesis of Salt Represented by Formula (I-16)



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3.75 Parts of a salt represented by formula (I-8-c′), 5.70 parts of a salt represented by formula (I-16-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 7.09 parts of a salt represented by formula (I-16).


MASS (ESI (+) Spectrum): M+ 339.1


MASS (ESI (−) Spectrum): M467.1


Example 3: Synthesis of Salt Represented by Formula (I-1373)



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6.77 Parts of a compound represented by formula (I-1373-a), 3.70 parts of a compound represented by formula (I-8-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated, and then 3 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 10.42 parts of a salt represented by formula (I-1373-c). 10.00 Parts of the resulting salt represented by formula (I-1373-c) and 20 parts of methanol were mixed, and after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 8.05 parts of a salt represented by formula (I-1373-c′).




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5.11 Parts of a salt represented by formula (I-1373-c′), 6.41 parts of a salt represented by formula (I-8-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 9.03 parts of a salt represented by formula (I-1373).


MASS (ESI (+) Spectrum): M+ 475.1


MASS (ESI (−) Spectrum): M517.1


Example 4: Synthesis of Salt Represented by Formula (I-1698)



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6.77 Parts of a compound represented by formula (I-1373-a), 4.42 parts of a compound represented by formula (I-1698-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated, and then 3 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 7.73 parts of a salt represented by formula (I-1698-c). 7.50 Parts of the resulting salt represented by formula (I-1698-c) and 15 parts of methanol were mixed and, after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 7.19 parts of a salt represented by formula (I-1698-c′).




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5.41 Parts of a salt represented by formula (I-1698-c′), 6.41 parts of a salt represented by formula (I-8-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether were added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 8.73 parts of a salt represented by formula (I-1698).


MASS (ESI (+) Spectrum): M+ 505.1


MASS (ESI (−) Spectrum): M517.1


Example 5: Synthesis of Salt Represented by Formula (I-1568)



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6.77 Parts of a compound represented by formula (I-1373-a), 6.72 parts of a compound represented by formula (I-1568-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated and then the concentrated mass was isolated using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: chloroform/methanol=1/1) to obtain 4.33 parts of a salt represented by formula (I-1568-c). 4.00 Parts of the resulting salt represented by formula (I-1568-c) and 8.00 parts of methanol were mixed, and after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 3.31 parts of a salt represented by formula (I-1568-c′).




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3.18 Parts of a salt represented by formula (I-1568-c′), 3.20 parts of a salt represented by formula (I-8-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 5.22 parts of a salt represented by formula (I-1568).


MASS (ESI (+) Spectrum): M+ 601.0


MASS (ESI (−) Spectrum): M517.1


Example 6: Synthesis of Salt Represented by Formula (I-1763)



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6.77 Parts of a compound represented by formula (I-1373-a), 5.33 parts of compound represented by formula (I-1763-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated and then the concentrated mass was isolated using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: chloroform/methanol=1/1) to obtain 5.19 parts of a salt represented by formula (I-1763-c). 5.00 Parts of the resulting salt represented by formula (I-1763-c) and 10 parts of methanol were mixed, and after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 4.45 parts of a salt represented by formula (I-1763-c′).




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5.79 Parts of a salt represented by formula (I-1763-c′), 3.20 parts of a salt represented by formula (I-8-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 4.89 parts of a salt represented by formula (I-1763).


MASS (ESI (+) Spectrum): M+ 543.1


MASS (ESI (−) Spectrum): M517.1


Example 7: Synthesis of Salt Represented by Formula (I-2998)



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6.73 Parts of a compound represented by formula (I-2998-a), 6.72 parts of a compound represented by formula (I-1568-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated and then the concentrated mass was isolated using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: chloroform/methanol=1/1) to obtain 4.39 parts of a salt represented by formula (I-2998-c). 4.00 Parts of the resulting salt represented by formula (I-2998-c) and 8.00 parts of methanol were mixed, and after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 3.24 parts of a salt represented by formula (I-2998-c′).




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3.17 Parts of a salt represented by formula (I-2998-c′), 3.20 parts of a salt represented by formula (I-8-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 5.08 parts of a salt represented by formula (I-2998).


MASS (ESI (+) Spectrum): M+ 599.0


MASS (ESI (−) Spectrum): M517.1


Example 8: Synthesis of Salt Represented by Formula (I-4821)



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3.17 Parts of a salt represented by formula (I-2998-c′), 3.22 parts of a salt represented by formula (I-4821-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 5.15 parts of a salt represented by formula (I-4821).


MASS (ESI (+) Spectrum): M+ 599.0


MASS (ESI (−) Spectrum): M541.2


Example 9: Synthesis of Salt Represented by Formula (I-5173)



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6.77 Parts of a compound represented by formula (I-1373-a), 5.09 parts of a compound represented by formula (I-5303-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 50 parts of an aqueous 25% tetramethylammonium hydroxide solution was added and, after stirring for 6 hours, the organic layer was isolated through separation. The organic layer thus obtained was concentrated, and then 3 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 7.08 parts of a salt represented by formula (I-5173-c). 7.00 Parts of the resulting salt represented by formula (I-5173-c) and 14 parts of methanol were mixed and, after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 6.52 parts of a salt represented by formula (I-5173-c′).




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5.27 Parts of a salt represented by formula (I-5173-c′), 6.41 parts of a salt represented by formula (I-8-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 8.29 parts of a salt represented by formula (I-5173).


MASS (ESI (+) Spectrum): M+ 491.1


MASS (ESI (−) Spectrum): M517.1


Example 10: Synthesis of Salt Represented by Formula (I-6413)



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6.77 Parts of a compound represented by formula (I-1373-a), 11.14 parts of a compound represented by formula (I-6413-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 50 parts of an aqueous 25% tetramethylammonium hydroxide solution was added and, after stirring for 6 hours, the organic layer was isolated through separation. The organic layer thus obtained was concentrated and then the concentrated mass was isolated using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: chloroform/methanol=1/1) to obtain 3.82 parts of a salt represented by formula (I-6413-c). 3.80 Parts of the resulting salt represented by formula (I-6413-c) and 7.60 parts of methanol were mixed and, after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 3.32 parts of a salt represented by formula (I-6413-c′).




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1.95 Parts of a salt represented by formula (I-6413-c′), 1.60 parts of a salt represented by formula (I-8-d), 60 parts of chloroform and 10 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 30 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 30 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 2.08 parts of a salt represented by formula (I-6413).


MASS (ESI (+) Spectrum): M+ 742.9


MASS (ESI (−) Spectrum): M517.1


Example 11: Synthesis of Salt Represented by Formula (I-7064)



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4.91 Parts of a compound represented by formula (I-7064-a), 6.72 parts of a compound represented by formula (I-1568-b) and 50 parts of dimethylformamide were mixed, followed by stirring at 23° C. for 30 minutes. The mixture thus obtained was cooled to 0° C., and then mixed with 5.05 parts of trifluoroacetic anhydride and 3.00 parts of trifluoromethanesulfonic acid, followed by stirring at 0° C. for 1 hour, temperature rise to 23° C. and further stirring at 23° C. for 6 hours. To the mixture thus obtained, 100 parts of chloroform and 50 parts of ion-exchanged water were added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. The organic layer thus obtained was concentrated and then the concentrated mass was isolated using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: chloroform/methanol=1/1) to obtain 3.65 parts of a salt represented by formula (I-7064-c). 3.50 Parts of the resulting salt represented by formula (I-7064-c) and 7.00 parts of methanol were mixed and, after stirring at 23° C. for 30 minutes, the mixed solution was isolated from a column (ion-exchange resin No. 6, 100-200 mesh; manufactured by Wako Pure Chemical Industries, Ltd.) to obtain 2.86 parts of a salt represented by formula (I-7064-c′).




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2.68 Parts of a salt represented by formula (I-7064-c′), 4.09 parts of a salt represented by formula (I-69-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 5.34 parts of a salt represented by formula (I-7064).


MASS (ESI (+) Spectrum): M+ 501.0


MASS (ESI (−) Spectrum): M694.9


Example 12: Synthesis of Salt Represented by Formula (I-7065)



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3.17 Parts of a salt represented by formula (I-2998-c′), 4.09 parts of a salt represented by formula (I-69-d), 40 parts of chloroform and 5 parts of acetonitrile were mixed, followed by stirring at 23° C. for 2 hours. To the mixture thus obtained, 20 parts of an aqueous 5% oxalic acid solution was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. To the organic layer thus obtained, 20 parts of ion-exchanged water was added and, after stirring at 23° C. for 30 minutes, the organic layer was isolated through separation. This water washing operation was repeated five times. The organic layer thus obtained was concentrated, and then 30 parts of tert-butyl methyl ether was added to the concentrated residue and, after stirring at 23° C. for 30 minutes, the supernatant was removed, followed by concentration to obtain 5.88 parts of a salt represented by formula (I-7065).


MASS (ESI (+) Spectrum): M+ 601.0


MASS (ESI (−) Spectrum): M694.9


Synthesis of Resin

Compounds (monomers) used in synthesis of a resin (A) are shown below. Hereinafter, these compounds are referred to as “monomer (a1-1-3)” or the like according to the formula number.




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Synthesis Example 1 [Synthesis of Resin A1]

Using a monomer (a1-2-6), a monomer (a2-C-3), a monomer (a3-4-2) and a monomer (a1-4-2) as monomers, these monomers were mixed in a molar ratio of 55:3:15:27 [monomer (a1-1-3):monomer (a1-2-6):monomer (a2-C-3):monomer (a3-4-2):monomer (a1-4-2)], and then this monomer mixture was mixed with methyl isobutyl ketone in the amount of 1.5 mass times the total mass of all monomers. To the mixture thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers, followed by heating at 73° C. for about 5 hours. Thereafter, to the polymerization reaction solution thus obtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight) was added in the amount of 2.0 mass times the total mass of the amount of all monomers, followed by stirring for 12 hours and further isolation through separation. The organic layer thus recovered was poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A1 having a weight-average molecular weight of about 5.5×103 in a yield of 86%. This resin A1 has the following structural units.




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Synthesis Example 2 [Synthesis of Resin A2]

Using a monomer (a1-2-6), a monomer (a2-C-3), a monomer (a3-4-2) and a monomer (a1-4-19) as monomers, these monomers were mixed in a molar ratio of 53:3:12:32 [monomer (a1-2-6):monomer (a2-C-3):monomer (a3-4-2):monomer (a1-4-19)], and then this monomer mixture was mixed with methyl isobutyl ketone in the amount of 1.5 mass times the total mass of all monomers. To the mixture thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers, followed by heating at 73° C. for about 5 hours. Thereafter, to the polymerization reaction solution thus obtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight) was added in the amount of 2.0 mass times the total mass of the amount of all monomers, followed by stirring for 12 hours and further isolation through separation. The organic layer thus recovered was poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A2 having a weight-average molecular weight of about 5.5×103 in a yield of 74%. This resin A2 has the following structural units.




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Synthesis Example 3 [Synthesis of Resin A3]

Using a monomer (a1-2-6), a monomer (a2-C-3), a monomer (a3-4-2) and a monomer (a1-4-13) as monomers, these monomers were mixed in a molar ratio of 53:3:12:32 [monomer (a1-2-6):monomer (a2-C-3):monomer (a3-4-2):monomer (a1-4-13)], and then this monomer mixture was mixed with methyl isobutyl ketone in the amount of 1.5 mass times the total mass of all monomers. To the mixture thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers, followed by heating at 73° C. for about 5 hours. Thereafter, to the polymerization reaction solution thus obtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight) was added in the amount of 2.0 mass times the total mass of the amount of all monomers, followed by stirring for 12 hours and further isolation through separation. The organic layer thus recovered was poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A3 having a weight-average molecular weight of about 5.1×103 in a yield of 79%. This resin A3 has the following structural units.




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Synthesis Example 4 [Synthesis of Resin A4]

Using a monomer (a1-6-8), a monomer (a2-1-3), a monomer (a3-4-2) and 4-acetoxystyrene as monomers, these monomers were mixed in a molar ratio of 55:3:15:27 [monomer (a1-C-3):monomer (a1-2-6):monomer (a2-C-3):monomer (a3-4-2):4-acetoxystyrene], and then this monomer mixture was mixed with methyl isobutyl ketone in the amount of 1.5 mass times the total mass of all monomers. To the mixture thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers, followed by heating at 73° C. for about 5 hours. Thereafter, to the polymerization reaction solution thus obtained, an aqueous 25% tetramethylammonium hydroxide solution was added, followed by stirring for 12 hours and further isolation through separation. The organic layer thus recovered was poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A4 having a weight-average molecular weight of about 5.4×103 in a yield of 80%. This resin A4 has the following structural units.




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<Preparation of Resist Composition>

As shown in Table 2, the following components were mixed and the mixture thus obtained was filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare resist compositions.














TABLE 2





Resist

Acid

Quencher



composition
Resin
generator
Salt (I)
(C)
PB/PEB







Composition 1
A1 =

I-8 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 2
A1 =

I-16 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 3
A1 =

I-1373 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 4
A1 =

I-1698
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 5
A1 =

I-1568 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 6
A1 =

I-1763 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 7
A1 =

I-2998
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 8
A1 =

I-4821
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 9
A1 =

I-5173 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 10
A1 =

I-6413 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 11
A1 =

I-7064 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 12
A1 =

I-7065
C1
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 13
A2 =

I-6413 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 14
A3 =

I-6413
C1
100° C./130° C.



10 parts

1.5 parts
0.35 part



Composition 15
A4 =

I-6413 =
C1 =
100° C./130° C.



10 parts

1.5 parts
0.35 part



Comparative
A1
I-8-c =

C1 =
100° C./130° C.


Composition 1
10 parts
1.5 parts

0.35 part





<Resin>


A1 to A4: Resin A1 to Resin A4


<salt (I) >


I-8: Salt represented by Formula (I-8)


I-16: Salt represented by Formula (I-16)


I-1373: Salt represented by Formula (I-1373)


I-1568: Salt represented by Formula (I-1568)


I-1698: Salt represented by Formula (I-1698)


I-1763: Salt represented by Formula (I-1763)


I-2998: Salt represented by Formula (1-2998)


I-4821: Salt represented by Formula (I-4821)


I-5173: Salt represented by Formula (I-5173)


I-6413: Salt represented by Formula (I-6413)


I-7064: Salt represented by Formula (I-7064)


I-7065: Salt represented by Formula (I-7065)


<Acid Generator>


I-8-c: Salt represented by Formula (I-8-c)


<Quencher (C) >


C1: Salt shown below synthesized by the method


mentioned in JP 2011-39502 A




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<Solvent>



Propylene glycol monomethyl ether acetate 400 parts


Propylene glycol monomethyl ether 100 parts


γ-Butyrolactone 5 parts







(Evaluation of Exposure of Resist Composition with Electron Beam, Organic Solvent Development)


Each 6 inch-diameter silicon wafer was treated with hexamethyldisilazane on a direct hot plate at 90° C. for 60 seconds. A resist composition was spin-coated on the silicon wafer in such a manner that the thickness of the composition layer became 0.04 μm. Then, the coated silicon wafer was prebaked on the direct hot plate at the temperature shown in the column “PB” of Table 2 for 60 seconds to form a composition layer. Using an electron-beam direct-write system (“ELS-F125 125 keV”, manufactured by ELIONIX INC.), line-and-space patterns (pitch of 60 nm/line width of 30 nm) were directly written on the composition layer formed on the wafer while changing the exposure dose stepwise.


After exposure, post-exposure baking was performed on the hot plate at the temperature shown in the column “PEB” of Table 2 for 60 seconds. Next, the composition layer on this silicon wafer was developed with butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developer at 23° C. for 20 seconds using the dynamic dispensing method to obtain resist patterns.


The resist patterns (line-and-space patterns) thus obtained were observed by a scanning electron microscope and effective sensitivity was expressed as the exposure dose at which a ratio of the line width to the space width of the line and space patterns with a pitch of 60 nm became 1:1 after exposure.


Evaluation of Line Edge Roughness (LER): Line edge roughness was determined by measuring a roughness width of the irregularity in wall surface of a resist pattern produced by the effective sensitivity using a scanning electron microscope. The results are shown in Table 3.












TABLE 3







Resist composition
LER




















Example 13
Composition 1
3.84



Example 14
Composition 2
3.76



Example 15
Composition 3
3.65



Example 16
Composition 4
3.59



Example 17
Composition 5
3.42



Example 18
Composition 6
3.49



Example 19
Composition 7
3.39



Example 20
Composition 8
3.48



Example 21
Composition 9
3.56



Example 22
Composition 10
3.24



Example 23
Composition 11
3.39



Example 24
Composition 12
3.34



Example 25
Composition 13
3.26



Example 26
Composition 14
3.22



Example 27
Composition 15
3.28



Comparative
Comparative
4.83



Example 1
Composition 1










As compared with Comparative Composition 1, Compositions 1 to 15 exhibited small roughness width of the irregularity in wall surface of a resist pattern, and satisfactory evaluation of the line edge roughness.


A resist composition including a salt of the present invention is capable of obtaining a resist pattern with satisfactory line edge roughness (LER), and is therefore useful for fine processing of semiconductors and is industrially extremely useful.

Claims
  • 1. A salt represented by formula (I):
  • 2. The salt according to claim 1, wherein Yb1 represents a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and —CH2— included in the cyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO2—.
  • 3. The salt according to claim 1, wherein an anion of the salt represented by formula (I) is an anion represented by formula (I-A1):
  • 4. The salt according to claim 1, wherein an anion of the salt represented by formula (I) is an anion represented by formula (I-A2):
  • 5. An acid generator comprising the salt according to claim 1.
  • 6. A resist composition comprising the acid generator according to claim 5.
  • 7. The resist composition according to claim 6, further comprising a resin including a structural unit having an acid-labile group, wherein the structural unit having an acid-labile group includes at least one selected from the group consisting of a structural unit represented by formula (a1-0), a structural unit represented by formula (a1-1), a structural unit represented by formula (a1-2), a structural unit represented by formula (a1-4), a structural unit represented by formula (a1-5) and a structural unit represented by formula (a1-6):
  • 8. The resist composition according to claim 6, further comprising a resin including a structural unit having an acid-labile group, wherein the resin including a structural unit having an acid-labile group further includes a structural unit represented by formula (a2-A):
  • 9. The resist composition according to claim 6, further comprising a salt generating an acid having an acidity lower than that of an acid generated from the acid generator.
  • 10. A method for producing a resist pattern, which comprises: (1) a step of applying the resist composition according to claim 6 on a substrate,(2) a step of drying the applied composition to form a composition layer,(3) a step of exposing the composition layer,(4) a step of heating the exposed composition layer, and(5) a step of developing the heated composition layer.
Priority Claims (1)
Number Date Country Kind
2023-062901 Apr 2023 JP national