Patent Application
20240272553
The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, an actinic ray-sensitive or radiation-sensitive film, a pattern forming method, and a method for manufacturing an electronic device.
Manufacturing processes for semiconductor devices such as ICs (Integrated Circuits) and LSI (Large Scale Integration) circuits involve lithographic microfabrication using a photosensitive composition.
Examples of the lithographic method include a method including forming a resist film using a photosensitive composition, exposing the film obtained to light, and then developing the film. In particular, in recent years, it is contemplated to use, in addition to ArF excimer laser light, EBs (Electron Beams) and EUV (Extreme Ultraviolet) light for light exposure, and actinic ray-sensitive or radiation-sensitive resin compositions suitable for EUV exposure are being developed.
When EUV light (wavelength: 13.5 nm) or an electron beam is used to form a resist pattern for the purpose of forming a fine pattern, the performance requirements are higher than those when conventional ArF light (wavelength: 193 nm) is used.
One known photosensitive composition includes a resin whose main chain is to be cleaved upon exposure to light. As a result, the molecular weight of the composition decreases, and therefore the contrast for development with a developer is improved. This photosensitive composition is used also as a photosensitive composition usable for the above-described light sources.
For example, JP2000-298345A discloses a positive-type radiation-sensitive composition that includes: a polymer having a structural unit having a group that is decomposed by the action of an acid and becomes an alkali-soluble group and a structural unit derived from an acrylate monomer having a halogen atom or a cyano group at the a position; and an acid generator that generates an acid upon irradiation with radiation.
JP2002-156760A discloses a positive-type radiation-sensitive composition including: a) a compound having a carboxyl group protected by an acid leaving group having three or more aromatic rings; and b) an acid generator that generates an acid upon irradiation with radiation. A copolymer of trityl α-chloroacrylate and p-hydroxy-α-methylstyrene etc. are described as specific examples of the a).
In recent years, patterns formed using EUV light or electron beams are being reduced in size, and there is a need for further improvement in various performance capabilities such as roughness performance.
In the pattern formation using the radiation sensitive compositions described in JP2000-298345A and JP2002-156760A and also in the conventional pattern formation including a main chain cleavage mechanism in which the main chain of the resin is to be cleaved upon exposure to light, the rectangularity of the pattern shape in the depth direction is insufficient due to a lack of contrast, and there is a room for improvement.
Accordingly, it is an object of the invention to provide an actinic ray-sensitive or radiation-sensitive resin composition having good roughness performance and capable of forming a pattern having good rectangularity.
It is another object of the invention to provide an actinic ray-sensitive or radiation-sensitive film using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, and a method for manufacturing an electronic device.
The inventors have found that the above objects can be achieved by the following.
In formula (1), X represents a halogen atom; LP represents —COO— or an arylene group; and RQ represents a hydrogen atom or an organic group.
In formula (2), R represents an alkyl group, and R1 represents a hydroxy group, a halogen atom, or an alkyl group. p represents an integer of from 0 to 5. When p is an integer of from 2 to 5, a plurality of R1s may be the same or different.
In formula (3), Y represents a halogen atom, a hydrogen atom, or an alkyl group. RQ1 to RQ3 each independently represent an alkyl group, a cycloalkyl group, or an alkenyl group, and two selected from the group consisting of RQ1 to RQ3 may be bonded together to form a ring.
[2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein a sum of a content of the repeating unit A with respect a total amount of repeating units included in the resin and a content of the repeating unit C with respect the total amount of the repeating units included in the resin is 60% by mole or more.
[3] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], wherein the content of the repeating unit C with respect to the total amount of repeating units included in the resin is 40% by mole or more.
[4] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [3], wherein the compound which generates an acid upon irradiation with actinic rays or radiation includes at least one selected from the group consisting of the following compounds (I) to (II):
[5] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [4], wherein the actinic ray-sensitive or radiation-sensitive resin composition further includes an acid diffusion control agent represented by the following formula (XN):
In formula (XN),
[6] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [5], wherein X in formula (1) is a chlorine atom.
[7] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [6], wherein R1 in formula (2) is a hydroxy group.
[8] An actinic ray-sensitive or radiation-sensitive film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [7].
[9] A pattern forming method including:
[10] The pattern forming method according to [9], wherein an exposure light source which emits EUV light is used.
[11] The pattern forming method according to [9] or [10], wherein the developer is alkali developer liquid.
[12] A method for manufacturing an electronic device, the method including the pattern forming method according to any one of [9] to [11].
The present invention can provide an actinic ray-sensitive or radiation-sensitive resin composition having good roughness performance and capable of forming a pattern having good rectangularity and can also provide an actinic ray-sensitive or radiation-sensitive film using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, and a method for manufacturing an electronic device.
The present invention will next be described in detail.
Description of structural requirements described below may be made on the basis of representative embodiments of the present invention. However, the invention is not limited to theses embodiments.
As for notations of groups (atomic groups) in the present specification, a notation that is not specified as substituted and unsubstituted is intended to encompass groups having no substituent and groups having a substituent, so long as the notation does not depart from the spirit of the invention. For example, an “alkyl group” is intended to encompass not only an alkyl group having no substituent (an unsubstituted alkyl group) but also an alkyl group having a substituent (a substituted alkyl group). In the present specification, an “organic group” is a group including at least one carbon atom.
Preferably, the substituent is a monovalent substituent, unless otherwise specified.
In the present specification, “actinic rays” or “radiation” means, for example, an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser light, extreme ultraviolet light (EUV light), X-rays, an electron beam (EB), etc.
In the present specification, “light” means actinic rays or radiation.
In the present specification, “exposure to light” is intended to encompass not only exposure to an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser light, extreme ultraviolet (EUV) light, X-rays, etc. but also image drawing using an electron beam or a particle beam such as an ion beam.
In the present specification, “to” is used to mean that numerical values before and after the “to” are used as the lower limit and the upper limit.
In the present specification, no limitation is imposed on the bonding direction of a divalent linking group, unless otherwise specified. For example, when Y in a compound represented by formula “X—Y—Z” is —COO—, Y may be —CO—O— or may be —O—CO—. This compound may be “X—CO—O—Z” or may be “X—O—CO—Z.”
In the present specification, (meth)acrylate is intended to refer to acrylate and methacrylate, and (meth)acrylic is intended to refer to acrylic and methacrylic.
In the present specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (hereinafter may be referred to also as the “molecular weight distribution”) (Mw/Mn) of a compound are defined as polystyrene-equivalent values determined by GPC (Gel Permeation Chromatography) measurement (solvent: tetrahydrofuran, flow rate (injection amount of a sample): 10 μL, columns: TSK gel Multipore HXL-M manufactured by TOSOH Corporation, column temperature: 40° C., flow velocity: 1.0 mL/minute, detector: differential refractive index detector) using a GPC apparatus (HLC-8120GPC manufactured by TOSOH Corporation).
In the present specification, the acid dissociation constant (pKa) is the pKa in an aqueous solution and is specifically a value determined by computation using the following software package 1 based on Hammett substituent constants and a database of known literature values.
Software package 1: Advanced Chemistry Development (ACD/Labs) Software V 8.14 for Solaris (1994-2007 ACD/Labs).
The pKa can also be determined by a molecular orbital calculation method. In one specific example of this method, H+ dissociation free energy in an aqueous solution is computed based on a thermodynamic cycle to compute the pKa. As for the method for computing the H+ dissociation free energy, the density functional theory (DFT), for example, can be used for the computation. Various other methods have been reported in literature etc., but the computation method is not limited thereto. There is a plurality of software applications capable of performing the DFT, and one example is Gaussian 16.
In the present specification, the pKa is a value determined by computation using the software package 1 based on Hammett substituent constants and the database of known literature values as described above. When the pKa cannot be computed using this method, a value obtained using Gaussian 16 based on the DFT (density functional theory) is used.
In the present specification, the pKa is a “value in an aqueous solution” as described above. When the pKa in an aqueous solution cannot be computed, the “pKa in a dimethyl sulfoxide (DMSO) solution” is used.
“Solids” are components forming an actinic ray-sensitive or radiation-sensitive film, and a solvent is not included. Any component included in the actinic ray-sensitive or radiation-sensitive film is considered as a solid component even when the component is in a liquid form.
The actinic ray-sensitive or radiation-sensitive resin composition of the invention will be described in detail.
The actinic ray-sensitive or radiation-sensitive resin composition is preferably a resist composition and may be a positive-type resist composition or a negative-type resist composition. The resist composition may be a resist composition for alkali development and may be a resist composition for organic solvent development.
The actinic ray-sensitive or radiation-sensitive resin composition of the invention is preferably a positive-type resist composition for alkali development.
The resist composition may be a chemical amplification-type resist composition and may be a non-chemical amplification-type resist composition. The resist composition is typically a chemical amplification-type resist composition.
The actinic ray-sensitive or radiation-sensitive resin composition of the invention (hereinafter referred to also as the “composition of the invention”) includes: a resin including a repeating unit A represented by formula (1) below, a repeating unit B represented by formula (2), and a repeating unit C represented by formula (3); and a compound that generates an acid upon irradiation with actinic rays or radiation:
In formula (1), X represents a halogen atom; LP represents —COO— or an arylene group; and RQ represents a hydrogen atom or an organic group.
In formula (2), R1 represents an alkyl group, and R1 represents a hydroxy group, a halogen atom, or an alkyl group. p represents an integer of from 0 to 5. When p is an integer of from 2 to 5, a plurality of R1s may be the same or different.
In formula (3), Y represents a halogen atom, a hydrogen atom, or an alkyl group. RQ1 to RQ3 each independently represent an alkyl group, a cycloalkyl group, or an alkenyl group, and two selected from the group consisting of RQ1 to RQ3 may be bonded together to form a ring.
The reason that the composition of the invention has good roughness performance and is capable of forming a pattern having good rectangularity is not fully clear. However, the inventors presume that the reason is as follows.
In a resist pattern forming mechanism including a main chain cleavage mechanism, an acid is generated upon exposure to light, and the main chain of the resin is cleaved. When the main chain is cleaved, the molecular weight of the resin in exposed portions decreases. In this case, the plasticity of the exposed portions increases, and the diffusion of the acid generated is facilitated.
Generally, the resist pattern forming mechanism including the main chain cleavage mechanism does not include a deprotecting mechanism through the action of an acid, i.e., a mechanism in which, in a resin including a structure having a polar group protected by a group (leaving group) that leaves by the action of an acid, the leaving group leaves by the action of an acid. Even with a composition having the resist pattern forming mechanism in combination with the deprotecting mechanism, the rectangularity of the pattern shape in its depth direction may be insufficient due to a shortage of contrast that is caused by the low reactivity of the leaving group, insufficient cleavage of the main chain, etc.
The resin included in the composition of the invention includes the repeating unit A that is represented by formula (1) and exhibits the main chain cleavage mechanism because the halogen atom is present at the a position and further includes the repeating unit C that is represented by formula (3) and has an acid-decomposable group (a group that is decomposed by the action of an acid and thereby increased in polarity) including a carboxyl group protected by a highly reactive leaving group. The main chain cleavage mechanism facilitates the diffusion of the acid, and the highly reactive leaving group included further facilitates deprotection by the acid with enhanced diffusion. These produce a synergistic effect, and the contrast can be significantly increased. In this case, not only the roughness performance but also the rectangularity of the shape can be improved.
Moreover, the resin included in the composition of the invention includes the repeating unit B represented by formula (2) and having an α-alkyl styrene structure. Since the α-alkyl styrene structure is included, the main chain cleavage starting from an α-halogen unit such as the repeating unit A represented by formula (1) is facilitated, and the contrast can be further increased. This may be the reason that the roughness performance and the rectangularity of the shape are further improved.
First, various components of the actinic ray-sensitive or radiation-sensitive resin composition will be described in detail.
The composition of the invention includes the resin (hereinafter referred to also as resin (A)) including the repeating unit A represented by formula (1) above, the repeating unit B represented by formula (2), and the repeating unit C represented by formula (3).
The resin (A) includes the repeating unit A represented by formula (1) below. Since the resin (A) includes the α-halogen unit represented by formula (1), the main chain cleavage mechanism develops upon exposure to light. The resin (A) is a resin whose main chain is to be cleaved upon exposure to light.
In formula (1), X represents a halogen atom, and LP represents —COO— or an arylene group. RQ represents a hydrogen atom or an organic group.
Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferred.
In formula (1), LP represents —COO— or an arylene group.
The arylene group represented by LP is preferably an arylene group having 6 to 14 carbon atoms, and examples thereof include a phenylene group, a naphthylene group, and an anthryl group.
In formula (1), RQ represents a hydrogen atom or an organic group.
Examples of the organic group represented by RQ include a group having a lactone group, a sultone groups, or a carbonate group, a group having an acid group, and a group having a hydroxy group.
The lactone or sultone group in the group having a lactone group, a sultone groups, or a carbonate group and represented by RQ can be any group so long as it has a lactone or sultone structure. The lactone or sultone structure is preferably a 5- to 7-membered lactone structure or a 5- to 7-membered sultone structure. In particular, a 5- to 7-membered lactone structure with another ring structure fused thereto to form a bicyclo or spiro structure or a 5- to 7-membered sultone structure with another ring structure fused thereto to form a bicyclo or spiro structure is more preferred.
Preferably, the lactone or sultone group is a lactone or sultone group formed by removing at least one hydrogen atom from a ring member atom of a lactone structure represented by any of the following formulas (LC1-1) to (LC1-21) or a sultone structure represented by any of the following formulas (SL1-1) to (SL1-3).
Each of the lactone and sultone structures may have a substituent (Rb2). Preferred examples of the substituent (Rb2) include alkyl groups having 1 to 8 carbon atoms, cycloalkyl groups having 4 to 7 carbon atoms, alkoxy groups having 1 to 8 carbon atoms, alkoxycarbonyl groups having 1 to 8 carbon atoms, a carboxy group, halogen atoms, a cyano group, and acid-decomposable groups. n2 represents an integer of from 0 to 4. A plurality of Rb2s present when n2 is 2 or more may be different from each other, and the plurality of Rb2s present may be bonded together to form a ring. The acid-decomposable group will be described later.
The carbonate group is preferably a cyclic carbonate group. The cyclic carbonate group may further have a substituent.
Preferably, the group having a lactone group, a sultone groups, or a carbonate group and represented by RQ is, for example, a group represented by the following formula (A-I).
-LQ1-RA1 (A-I)
In formula (A-I), LQ1 represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxy group, or a divalent linking group formed by combining any of the above groups. In particular, LQ1 is preferably a single bond or a linking group represented by -LQ2-CO2—. LQ2 is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group and is preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group.
RA1 represents a group formed by removing one hydrogen atom from a ring member atom in the lactone structure represented by any of formulas (LC1-1) to (LC1-21), a group formed by removing one hydrogen atom from a ring member atom in the sultone structure represented by any of formulas (SL1-1) to (SL1-3), or a cyclic carbonate group.
When the repeating unit A having the lactone or sultone group and represented by formula (1) has optical isomers, any of the optical isomers may be used. One optical isomer may be used alone, or a mixture of a plurality of optical isomers may be used. When one optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more and more preferably 95 or more.
The acid group in the group having an acid group and represented by RQ is preferably an acid group having a pKa of 13 or less. The acid dissociation constant of the acid group is preferably 13 or less, more preferably 3 to 13, and still more preferably 5 to 10.
The acid group is preferably, for example, a carboxy group, a phenolic hydroxy group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic group, a sulfonamido group, or an isopropanol group.
In the hexafluoroisopropanol group, one or more (preferably one to two) fluorine atoms may each be replaced with a group other than a fluorine atom (such as an alkoxycarbonyl group).
The acid group is also preferably —C(CF3)(OH)—CF2— formed as described above. At least one fluorine atom may be replaced with a group other than a fluorine atom to form a ring including —C(CF3)(OH)—CF2—.
The acid group is more preferably a phenolic hydroxy group or a fluorinated alcohol group.
The group having the acid group is more preferably an aryl group substituted with a hydroxy group or a hydrocarbon group substituted with a fluorinated alcohol group.
The aryl group represented by RQ and substituted with a hydroxy group is preferably an aryl group having 6 to 14 carbon atoms and substituted with a hydroxy group and more preferably a group represented by the following formula (A-II).
In formula (A-II), RA2 represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group, or an aryloxycarbonyl group. When a plurality of RA2s is present, they may be the same or different. When a plurality of RA2s is present, they may together form a ring. RA2 is preferably a hydrogen atom. a represents an integer of from 1 to 3. b represents an integer of 0 to (5-a).
The hydrocarbon group represented by RQ and substituted with a fluorinated alcohol group is preferably a group represented by the following formula (A-III).
-LQ3-(RA3)c (A-III)
In formula (A-III), LQ3 represents a (c+1) valent hydrocarbon group. RA3 represents a fluorinated alcohol group. When a plurality of RA3s is present, they may be the same or different. c represents an integer of from 1 to 3.
When the hydrocarbon group represented by LQ3 is, for example, a divalent hydrocarbon group, the divalent hydrocarbon group is, for example, a linear or branched alkylene group, a monocyclic or polycyclic cycloalkylene group, a monocyclic or polycyclic arylene group, or a divalent group formed by combining any of these groups.
The alkylene group is preferably an alkylene group having 1 to 4 carbon atoms such as a methylene group, an ethylene group, a n-propylene group, an isopropylene group, a n-butylene group, or an isobutylene group.
The cycloalkylene group is preferably a cycloalkylene group having 5 to 14 carbon atoms and preferably a monocyclic cycloalkylene group such as a cyclopentylene group or a cyclohexylene group or a polycyclic cycloalkylene group formed by removing one hydrogen atom from a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group.
The arylene group is preferably an arylene group having 6 to 14 carbon atoms, and examples thereof include a phenylene group, a naphthylene group, and an anthryl group.
Examples of the (c+1) valent hydrocarbon group include a group formed by removing (c-1) hydrogen atoms from any of the divalent hydrocarbon groups described above.
RA3 represents a fluorinated alcohol group and is preferably a hexafluoroisopropanol group.
c represents an integer of from 1 to 3 and is preferably 1 or 2.
The group having a hydroxy group and represented by RQ is preferably a group having an alicyclic hydrocarbon structure substituted with a hydroxy group.
The alicyclic hydrocarbon structure is preferably an adamantyl group, a diamantyl group, or a norbornane group.
The group having a hydroxy group and represented by RQ is preferably a group represented by any of the following formulas (VIIa) to (VIIc).
In formulas (VIIa) to (VIIc),
R2c to R4c each independently represent a hydrogen atom or a hydroxy group. At least one selected from the group consisting of R2c to R4c represents a hydroxy group. Preferably, one or two selected from the group consisting of R2c to R4c are each a hydroxy group, with the rest being a hydrogen atom.
In formula (VIIa), it is more preferable that two selected from the group consisting of R2c to R4c are each a hydroxy group, with the rest being a hydrogen atom.
Specific examples of the repeating unit A represented by formula (1) are shown below. However, the present invention is not limited thereto. In the following structural formulas, * represents a direct bond.
One type of repeating unit A may be used, or a combination of plurality of types may be used.
From the viewpoint of improving the efficiency of main chain cleavage, the content of the repeating unit A in the resin (A) with respect to the total amount of repeating units included in the resin (A) is preferably 10% by mole or more and more preferably 20% by mole or more. The upper limit of the content is preferably 70% by mole or less and more preferably 60% by mole or less.
From the viewpoint of improving the efficiency of main chain cleavage and increasing the contrast, the sum of the content of the repeating unit A with respect to the total amount of the repeating units included in the resin (A) and the content of the repeating unit C described later is preferably 60% by mole or more, more preferably 65% by mole or more, and still more preferably 70% by mole or more. The upper limit of the sum is preferably 90% by mole or less and more preferably 85% by mole or less.
The resin (A) includes the repeating unit B represented by the following formula (2). The resin (A) includes the α-alkyl styrene unit represented by formula (2), and this may be the reason that the main chain cleavage starting from the α-halogen unit represented by formula (1) upon exposure to light is facilitated.
In formula (2), R represents an alkyl group, and R1 represents a hydroxy group, a halogen atom, or an alkyl group. p represents an integer of from 0 to 5. When p is an integer of from 2 to 5, a plurality of R1 may be the same or different.
In formula (2), R represents an alkyl group.
The alkyl group represented by R may be linear or branched and is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group.
In formula (2), R1 represents a hydroxy group, a halogen atom, or an alkyl group.
Examples of the halogen atom represented by R1 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The alkyl group represented by R1 may be linear or branched and is preferably an alkyl group having 1 to 6 carbon atoms and more preferably an alkyl group having 1 to 3 carbon atoms.
The alkyl group represented by R1 may have a substituent, and examples of the substituent include halogen atoms, a hydroxy group, and alkoxy groups.
R1 represents preferably a hydroxy group, a fluorine atom, an iodine atom, or a trifluoromethyl group and represents more preferably a hydroxy group, from the viewpoint of increasing sensitivity.
In formula (2), p represents an integer of from 0 to 5.
p is preferably an integer of from 1 to 3 and more preferably 1.
Specific examples of the repeating unit B represented by formula (2) are shown below, but the invention is not limited thereto. In the following structural formulas, * represents a direct bond.
One type of repeating unit B may be used, or a combination of two or more types may be used.
The content of the repeating unit B in the resin (A) with respect to the total amount of the repeating units included in the resin (A) is preferably 10% by mole or more and more preferably 15% by mole or more. The upper limit of the content is preferably 50% by mole or less and more preferably 45% by mole or less.
The resin (A) includes the repeating unit C represented by formula (3) below and having an acid-decomposable group. The acid-decomposable group is a group that is decomposed by the action of an acid to generate a polar group. Specifically, the resin (A) has a repeating unit having a group that is decomposed by the action of an acid to generate a polar group. The resin having this repeating unit is increased in polarity by the action of an acid. In this case, the degree of solubility in alkali developer liquid increases, and the degree of solubility in an organic solvent decreases. The acid-decomposable group included in the repeating unit C has a highly reactive leaving group, and therefore deprotection by the action of an acid further proceeds, so that the contrast can be significantly increased.
In formula (3), Y represents a halogen atom, a hydrogen atom, or an alkyl group. RQ1 to RQ3 each independently represent an alkyl group, a cycloalkyl group, or an alkenyl group. Two selected from the group consisting of RQ1 to RQ3 may be bonded together to form a ring.
In formula (3), Y represents a halogen atom, a hydrogen atom, or an alkyl group.
Examples of the halogen atom represented by Y include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and the halogen atom is preferably a fluorine atom or a chlorine atom and more preferably a chlorine atom.
When Y represents a halogen atom, the repeating unit C also serves as a starting point of main chain cleavage upon exposure to light.
The alkyl group represented by Y may be linear or branched and is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group.
Y represents preferably a halogen atom or an alkyl group, more preferably a fluorine atom, a chlorine atom, or a methyl group, and still more preferably a chlorine atom.
In formula (3), RQ1 to RQ3 each independently represent an alkyl group (which may be linear or branched), a cycloalkyl group (which may be monocyclic or polycyclic), or an alkenyl group (which may be linear or branched).
Two selected from the group consisting of RQ1 to RQ3 may be bonded together to form a monocyclic or polycyclic ring.
The alkyl group represented by each of RQ1 to RQ3 is preferably an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, or a t-butyl group.
The cycloalkyl group represented by each of RQ1 to RQ3 is preferably a cycloalkyl group having 5 to 14 carbon atoms and preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group.
The alkenyl group represented by each of RQ1 to RQ3 is preferably an alkenyl group having 2 to 5 carbon atoms and is preferably a vinyl group.
The ring formed by bonding two selected from the group consisting of RQ1 to RQ3 is preferably a cycloalkyl group. The cycloalkyl group formed by bonding two selected from the group consisting of RQ1 to RQ3 is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group and is more preferably a monocyclic cycloalkyl group having 5 to 6 carbon atoms.
In the cycloalkyl group formed by bonding two selected from the group consisting of RQ1 to RQ3, one methylene group included in the ring may be replaced with a heteroatom such as an oxygen atom, a heteroatom-containing group such as a carbonyl group, or a vinylidene group. In the cycloalkyl group, at least one ethylene group included in the cycloalkane ring may be replaced with a vinylene group.
In a preferred mode of RQ1 to RQ3, for example, RQ1 is a methyl group or an ethyl group, and RQ2 and RQ3 are bonded together to form the cycloalkyl group described above.
The alkyl, cycloalkyl, and alkenyl groups represented by RQ1 to RQ3 and the ring formed by bonding two selected from the group consisting of RQ1 to RQ3 may each further have a substituent. No particular limitation is imposed on the substituent. Examples of the substituent include alkyl groups (having 1 to 4 carbon atoms), halogen atoms, a hydroxy group, alkoxy groups (having 1 to 4 carbon atoms), a carboxyl group, and alkoxycarbonyl groups (having 2 to 6 carbon atoms). The alkyl and alkoxy groups serving as substituents may each be further substituted with an additional substituent (such as a halogen atom or a hydroxy group). The number of carbon atoms in the substituent is preferably 8 or less.
Specific examples of the repeating unit C represented by formula (3) are shown below, but the invention is not limited thereto. In the following structural formulas, * represents a direct bond.
One type of repeating unit C may be used, or a combination of two or more types may be used.
From the viewpoint of increasing the contrast, the content of the repeating unit C in the resin (A) with respect to the total amount of the repeating units included in the resin (A) is preferably 40% by mole or more, more preferably 45% by mole or more, and still more preferably 50% by mole or more. The upper limit of the content is preferably 75% by mole or less and more preferably 70% by mole or less.
As described above, the sum of the content of the repeating unit A and the content of the repeating unit C with respect to the total amount of the repeating units included in the resin (A) is preferably 60% by mole or more, more preferably 65% by mole or more, and still more preferably 70% by mole or more. The upper limit of the sum is preferably 90% by mole or less and more preferably 85% by mole or less.
As described above, the sum of the content of the repeating unit A, the content of the repeating unit B, and the content of the repeating unit C with respect to the total amount of the repeating units included in the resin (A) is preferably 75% by mole or more and more preferably 80% by mole or more. The upper limit of the sum is preferably 100% by mole or less and more preferably 95% by mole or less.
The resin (A) may include additional repeating units other than the repeating units A to C so long as the effects of the invention are not impaired.
The resin (A) may include at least one repeating unit selected from the following group A and/or at least one repeating unit selected from the following group B.
Group A: The group consisting of the following repeating units (20) to (25).
Repeating units represented by formulas (A) to (E) described later correspond to (25) the repeating unit for reducing the mobility of the main chain.
Group B: The group consisting of the following repeating units (30) to (32).
The resin (A) has preferably an acid group and includes preferably a repeating unit having an acid group as described later. The definition of the acid group will be described later along with preferred modes of the repeating unit having an acid group. When the resin (A) has the acid group, the interaction between the resin (A) and the acid generated from the photoacid generator is enhanced. This results in a further reduction in diffusion of the acid to unexposed portions, and a pattern to be formed may have a sharper rectangular cross-sectional shape.
The resin (A) may have at least one repeating unit selected from the group A. When the composition of the invention is used as an actinic ray-sensitive or radiation-sensitive resin composition for EUV exposure, it is preferable that the resin (A) has at least one repeating unit selected from the group A.
The resin (A) may include at least one of a fluorine atom or an iodine atom. When the composition of the invention is used as an actinic ray-sensitive or radiation-sensitive resin composition for EUV exposure, it is preferable that the resin (A) includes at least one of a fluorine atom or an iodine atom. When the resin (A) includes both a fluorine atom and an iodine atom, the resin (A) may have one type of repeating unit including both a fluorine atom and an iodine atom or may include two types of repeating units including a repeating unit including a fluorine atom and a repeating unit including an iodine atom.
The resin (A) may have a repeating unit having an aromatic group. When the composition of the invention is used as an actinic ray-sensitive or radiation-sensitive resin composition for EUV exposure, it is also preferable that the resin (A) has a repeating unit having an aromatic group.
The resin (A) may have at least one repeating unit selected from the group B. When the composition of the invention is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF light, it is preferable that the resin (A) has at least one type of repeating unit selected from the group B.
When the composition of the invention is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF light, it is preferable that the resin (A) includes no fluorine atom and no silicon atom.
The resin (A) may have a repeating unit having an acid group in addition to the repeating units A to C.
The acid group is preferably an acid group having a pKa of 13 or less. The acid dissociation constant of the acid group is preferably 13 or less, more preferably 3 to 13, and still more preferably 5 to 10.
When the resin (A) has the acid group having a pKa of 13 or less, no particular limitation is imposed on the total content of the acid group in the resin (A), but the content is often 0.2 to 6.0 mmol/g. In particular, the content is preferably 0.8 to 6.0 mmol/g, more preferably 1.2 to 5.0 mmol/g, and still more preferably 1.6 to 4.0 mmol/g. When the content of the acid group is within the above range, development proceeds smoothly, and a pattern to be formed has a good profile, so that high resolution is achieved.
The acid group is preferably, for example, a carboxy group, a phenolic hydroxy group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic group, a sulfonamido group, or an isopropanol group.
In the hexafluoroisopropanol group, one or more (preferably one to two) fluorine atoms may each be replaced with a group other than a fluorine atom (such as an alkoxycarbonyl group).
The acid group is also preferably —C(CF3)(OH)—CF2— formed as described above. At least one fluorine atom may be replaced with a group other than a fluorine atom to form a ring including —C(CF3)(OH)—CF2—.
Preferably, the repeating unit having the acid group is a repeating unit different from a repeating unit having a lactone group, a sultone group, or a carbonate group that is described later.
The repeating unit having the acid group may have a fluorine atom or an iodine atom.
Examples of the repeating unit having the acid group include the following repeating units.
The repeating unit having the acid group is preferably a repeating unit represented by the following formula (1).
In formula (1), A represents a hydrogen atom, a cycloalkyl group, a halogen atom, or a cyano group. R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group, or an aryloxycarbonyl group. When a plurality of Rs is present, they may be the same or different. When a plurality of Rs is present, they may together form a ring. R is preferably a hydrogen atom. a represents an integer of from 1 to 3. b represents and integer of 0 to (5-a).
Examples of the repeating unit having the acid group are shown below. In these formulas, a represents 1 or 2.
Among the above repeating units, repeating units specifically described below are preferred. In the following formulas, R represents a hydrogen atom or a methyl group, and a represents 2 or 3.
The content of the repeating unit having the acid group with respect to the total amount of the repeating units in the resin (A) is preferably 10% by mole or more and more preferably 15% by mole or more. The upper limit of the content with respect to the total amount of the repeating units in the resin (A) is preferably 70% by mole or less, more preferably 65% by mole or less, and still more preferably 60% by mole or less. When the repeating unit A and/or the repeating unit B has an acid group, it is preferable that the total content of the repeating units including the repeating unit A and/or the repeating unit B falls within the above range.
The resin (A) may have, in addition to the above-described repeating units A to C and the above-described <repeating unit having the acid group>, a repeating unit having no acid-decomposable group and no acid group but having a fluorine atom, a bromine atom, or an iodine atom (this repeating unit is hereinafter referred to also as a unit X). Preferably, the <repeating unit having no acid-decomposable group and no acid group but having a fluorine atom, a bromine atom, or an iodine atom> differs from other types of repeating units belonging to the group A such as the <repeating unit having a lactone group, a sultone group, or a carbonate group> described later and the <repeating unit having a photoacid generating group> described later.
The unit X is preferably a repeating unit represented by formula (C).
L5 represents a single bond or an ester group. R9 represents a hydrogen atom or an alkyl group optionally having a fluorine atom or an iodine atom. R10 represents a hydrogen atom, an alkyl group optionally having a fluorine atom or an iodine atom, a cycloalkyl group optionally having a fluorine atom or an iodine atom, an aryl group optionally having a fluorine atom or an iodine atom, or a combination thereof.
The repeating unit represented by formula (C) is a repeating unit different from the repeating unit B represented by formula (2) above.
Examples of the repeating unit having a fluorine atom or an iodine atom are shown below.
The content of the unit X with respect to the total amount of the repeating units in the resin (A) is preferably 0% by mole or more, more preferably 5% by mole or more, and still more preferably 10% by mole or more. The upper limit of the content of the unit X with respect to the total amount of the repeating units in the resin (A) is preferably 50% by mole or less, more preferably 45% by mole or less, and still more preferably 40% by mole or less.
Among the repeating units in the resin (A), the total amount of repeating units including at least one of a fluorine atom, a bromine atom, or an iodine atom with respect to the total amount of the repeating units in the resin (A) is preferably 10% by mole or more, more preferably 20% by mole or more, still more preferably 30% by mole or more, and particularly preferably 40% by mole or more. No particular limitation is imposed on the upper limit of the total amount, but the amount with respect to the total amount of the repeating units in the resin (A) is, for example, 100% by mole or less.
Examples of the repeating units including at least one of a fluorine atom, a bromine atom, or an iodine atom include: a repeating unit having a fluorine atom, a bromine atom, or an iodine atom and having the acid-decomposable group; a repeating unit having a fluorine atom, a bromine atom, or an iodine atom and having the acid group; and a repeating unit having a fluorine atom, a bromine atom, or an iodine atom. When the repeating units A to C are each a repeating unit including at least one of a fluorine atom, a bromine atom, or an iodine atom, it is preferable that the total content of the repeating units including the repeating units A to C falls within the above range.
The resin (A) may have, in addition to the repeating units A to C, a repeating unit having at least one selected from the group consisting of lactone groups, sultone groups, and carbonate groups (this repeating unit is hereafter referred to also as a “unit Y”).
It is also preferable that the unit Y does not have a hydroxy group and an acid group such as a hexafluoropropanol group.
The lactone or sultone group may be any lactone or sultone group so long as it has a lactone or sultone structure. The lactone or sultone structure is preferably a 5- to 7-membered lactone or sultone structure. In particular, a 5- to 7-membered lactone structure with another ring structure fused thereto to form a bicyclo or spiro structure or a 5- to 7-membered sultone structure with another ring structure fused thereto to form a bicyclo or spiro structure is more preferred.
Preferably, the resin (A) has a repeating unit having a lactone or sultone group formed by removing at least one hydrogen atom from a ring member atom of a lactone structure represented by any of the above-described formulas (LC1-1) to (LC1-21) or a sultone structure represented by any of the above-described formulas (SL1-1) to (SL1-3), and the lactone or sultone group may be bonded directly to the main chain. For example, a ring member atom of the lactone or sultone group may be included in the main chain of the resin (A).
Examples of the repeating unit having a group including the lactone structure represented by any of formulas (LC1-1) to (LC1-21) or the sultone structure represented by any of formulas (SL1-1) to (SL1-3) include a repeating unit represented by the following formula (AI).
In formula (AI), Rb0 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by Rb0 may have a substituent, and preferred examples of the substituent include a hydroxy group and halogen atoms.
Rb0 is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxy group, or a divalent linking group formed by combining any of the above groups. In particular, Ab is preferably a single bond or a linking group represented by -Ab1-CO2—. Ab1 is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group and is preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group.
V represents a group formed by removing one hydrogen atom from a ring member atom in the lactone structure represented by any of formulas (LC1-1) to (LC1-21) or a group formed by removing one hydrogen atom from a ring member atom in the sultone structure represented by any of formulas (SL1-1) to (SL1-3).
When the repeating unit having the lactone or sultone group has optical isomers, any of the optical isomers may be used. One optical isomer may be used alone, or a mixture of a plurality of optical isomers may be used. When one optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more and more preferably 95 or more.
The carbonate group is preferably a cyclic carbonate group.
The repeating unit having a cyclic carbonate group is preferably a repeating unit represented by the following formula (A-1).
In formula (A-1), RA1 represents a hydrogen atom or a monovalent organic group (preferably a methyl group). n represents an integer of 0 or more. RA2 represents a substituent. A plurality of RA2s present when n is 2 or more may be the same or different. A represents a single bond or a divalent linking group. The divalent linking group is preferably an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxy group, or a divalent linking group formed by combining any of them. Z represents an atomic group forming a monocyclic or polycyclic ring together with a group represented by —O—CO—O— in formula (A-1).
Examples of the unit Y are shown below. In these formulas, Rx represents a hydrogen atom, —CH3, —CH2OH, or —CF3. In the following structural formulas, Me represents a methyl group.
(In the following formulas, Rx is H, CH3, CH2OH, or CF3.)
(In the following formulas, Rx is H, CH3, CH2OH, or CF3.)
The total content of repeating units having a lactone group, a sultone group, or a carbonate group among the repeating units in the resin (A) with respect to the total amount of the repeating units in the resin (A) is preferably 1% by mole or more and more preferably 10% by mole or more. The upper limit of the content with respect to the total amount of the repeating units in the resin (A) is preferably 85% by mole or less, more preferably 80% by mole or less, still more preferably 70% by mole or less, and particularly preferably 60% by mole or less.
When the repeating unit A is a repeating unit having a lactone group, a sultone group, or a carbonate group, it is preferable that the total content of the repeating units including the repeating unit A falls within the above range.
The resin (A) may include, in addition to the repeating units A to C and the repeating units described above, a repeating unit having a group that is decomposed to generate an acid upon irradiation with actinic rays or radiation (this group is hereinafter referred to also as a “photoacid generating group”).
Examples of the repeating unit having the photoacid generating group include a repeating unit represented by formula (4).
R41 represents a hydrogen atom or a methyl group. L41 represent a single bond or a divalent linking group. L42 represents a divalent linking group. R40 represents a structural moiety that is decomposed to generate an acid on a side chain upon irradiation with actinic rays or radiation.
Examples of the repeating unit having the photoacid generating group are shown below.
Other examples of the repeating unit represented by formula (4) include repeating units described in paragraphs [0094] to [0105] of JP2014-041327A and repeating units described in paragraph [0094] of WO2018/193954A.
The content of the repeating unit having the photoacid generating group with respect to the total amount of the repeating units in the resin (A) is preferably 1% by mole or more and more preferably 5% by mole or more. The upper limit of the content with respect to the total amount of the repeating units in the resin (A) is preferably 40% by mole or less, more preferably 35% by mole or less, and still more preferably 30% by mole or less.
The resin (A) may have a repeating unit represented by the following formula (V-1) or (V-2).
Preferably, the repeating unit represented by the following formula (V-1) or (V-2) differs from the repeating units described above.
In these formulas, R6 and R7 each independently represent a hydrogen atom, a hydroxy group, an alkyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (—OCOR or —COOR: R represents an alkyl group having 1 to 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms), or a carboxy group. The alkyl group is preferably a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms.
n3 represents an integer of from 0 to 6.
n4 represents an integer of from 0 to 4.
X4 is a methylene group, an oxygen atom, or a sulfur atom.
Examples of the repeating unit represented by formula (V-1) or (V-2) are shown below.
Examples of the repeating unit represented by formula (V-1) or (V-2) include repeating units described in paragraph [0100] of WO2018/193954A.
The higher the glass transition temperature (Tg) of the resin (A), the better because excessive diffusion of the acid generated or pattern collapse during development can be prevented. The Tg is preferably higher than 90° C., more preferably higher than 100° C., still more preferably higher than 110° C., and particularly preferably higher than 125° C. The Tg is preferably 400° C. or lower and more preferably 350° C. or lower because the rate of dissolution in a developer is high.
In the present specification, the glass transition temperature (Tg) of a polymer such as the resin (A) (hereinafter referred to as the “Tg of a repeating unit”) is computed by the following method. First, the Tg of each of the homopolymers formed from the respective repeating units included in the polymer is computed by the Bicerano method. Next, the mass ratios (%) of the repeating units with respect to the total mass of the repeating units in the polymer are computed. Next, the Tg of each repeating unit at the corresponding mass ratio is computed using the Fox formula (described, for example, in Materials Letters 62 (2008) 3152), and the computed Tg's are summed to obtain the Tg (° C.) of the polymer.
The Bicerano method is described in Prediction of polymer properties, Marcel Dekker Inc, New York (1993). The computation of Tg by the Bicerano method can be performed using software for estimating physical properties of a polymer, MDL Polymer (MDL Information Systems, Inc.).
To increase the Tg of the resin (A) (to increase the Tg to preferably higher than 90° C.), it is preferable to reduce the mobility of the main chain of the resin (A). Examples of a method for reducing the mobility of the main chain of the resin (A) include methods (a) to (e) described below.
Preferably, the resin (A) has a repeating unit whose homopolymer has a Tg of 130° C. or higher.
No particular limitation is imposed on the type of repeating unit whose homopolymer has a Tg of 130° C. or higher, and any repeating unit can be used so long as the Tg of the homopolymer computed by the Bicerano method is 130° C. or higher. With repeating units represented by formulas (A) to (E) described below, homopolymers formed from the repeating units can have a Tg of 130° C. or higher, but this depends on the types of functional groups in the repeating units.
One specific example of means for achieving the method (a) is a method in which the repeating unit represented by formula (A) is introduced into the resin (A).
In formula (A), RA represents a group including a polycyclic structure. Rx represents a hydrogen atom, a methyl group, or an ethyl group. The group including the polycyclic structure is a group including a plurality of ring structures, and the plurality of ring structures may or may not be fused.
Specific examples of the repeating unit represented by formula (A) include those described in paragraphs [0107] to [0119] of WO2018/193954A.
One specific example of means for achieving the method (b) is a method in which the repeating unit represented by formula (B) is introduced into the resin (A).
In formula (B), Rb1 to Rb4 each independently represent a hydrogen atom or an organic group, and at least two selected from the group consisting of Rb1 to Rb4 each represent an organic group.
When at least one of the organic groups is a group whose ring structure is linked directly to the main chain of the repeating unit, no particular limitation is imposed on the types of other organic groups.
When each of the organic groups is not a group whose ring structure is linked directly to the main chain of the repeating unit, at least two of the organic groups are each a substituent in which the number of constituent atoms excluding hydrogen atoms is 3 or more.
Specific examples of the repeating unit represented by formula (B) include those described in paragraphs [0113] to [0115] of WO2018/193954A.
One specific example of means for achieving the method (c) is a method in which the repeating unit represented by formula (C) is introduced into the resin (A).
In formula (C), Rc1 to Rc4 each independently represent a hydrogen atom or an organic group, and at least one of Rc1, Rc2, Rc3, or Rc4 is a group including a hydrogen-bonding hydrogen atom at a position within 3 atoms from a carbon atom in the main chain. In particular, it is preferable that the hydrogen-bonding hydrogen atom is present at a position within two atoms (at a position closer to the main chain) in order to induce the interaction between the main chains of molecules of the resin (A).
Specific examples of the repeating unit represented by formula (C) include those described in paragraphs [0119] to [0121] of WO2018/193954A.
One specific example of means for achieving the method (d) is a method in which the repeating unit represented by formula (D) is introduced into the resin (A).
In formula D, “Cyclic” represents a group having a ring structure forming the main chain. No particular limitation is imposed on the number of atoms forming the ring.
Specific examples of the repeating unit represented by formula (D) include those described in paragraphs [0126] to [0127] of WO2018/193954A.
One specific example of means for achieving the method (e) is a method in which the repeating unit represented by formula (E) is introduced into the resin (A).
In formula (E), Re's each independently represent a hydrogen atom or an organic group. Examples of the organic group include alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, and alkenyl groups, each of which may have a substituent.
“Cyclic” is a cyclic group including a carbon atom included in the main chain. No particular limitation is imposed on the number of atoms included in the cyclic group.
Specific examples of the repeating unit represented by formula (E) include those described in paragraphs [0131] to [0133] of WO2018/193954A.
(Repeating Unit Having at Least One Group Selected from Group Consisting of Lactone Groups, Sultone Groups, Carbonate Groups, Hydroxy Group, Cyano Group, and Alkali-Soluble Groups)
The resin (A) may have, in addition to the repeating units A to C, a repeating unit having at least one group selected from the group consisting of lactone groups, sultone groups, carbonate groups, a hydroxy group, a cyano group, and alkali-soluble groups.
Examples of the repeating unit having a lactone group, a sultone group, or a carbonate group and included in the resin (A) include: repeating units in which RQ in formula (1) representing the <repeating unit A> is a group having a lactone group, a sultone groups, or a carbonate group; and the repeating units described above for the <repeating unit having a lactone group, a sultone group, or a carbonate group>. A preferred content of the repeating unit is also as described above for the <repeating unit having a lactone group, a sultone group, or a carbonate group>.
The resin (A) may have, in addition to the repeating units A to C, a repeating unit having a hydroxy group or a cyano group. In this case, the adhesiveness to a substrate and the affinity for a developer are improved.
The repeating unit having a hydroxy group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxy group or a cyano group.
Preferably, the repeating unit having a hydroxy group or a cyano group has no acid-decomposable group. Examples of the repeating unit having a hydroxy group or a cyano group include those described in paragraphs [0081] to [0084] of JP2014-098921A.
The resin (A) may have, in addition to the repeating units A to C, a repeating unit having an alkali-soluble group.
Examples of the alkali-soluble group include a carboxy group, a sulfonamido group, a sulfonylimido group, a bissulfonylimido group, and aliphatic alcohol groups substituted with an electron-withdrawing group at the α-position (e.g., a hexafluoroisopropanol group), and the alkali-soluble group is preferably a carboxy group. When the resin (A) includes the repeating unit having an alkali-soluble group, resolution in contact hole applications is increased. Examples of the repeating unit having an alkali-soluble group include those described in paragraphs [0085] and [0086] of JP2014-098921A.
The resin (A) may have, in addition to the repeating units A to C, a repeating unit having an alicyclic hydrocarbon structure and exhibiting no acid decomposability. In this case, elution of a low-molecular weight component from the resist film to an immersion liquid during liquid immersion exposure can be reduced. Examples of the repeating unit having an alicyclic hydrocarbon structure and exhibiting no acid decomposability include repeating units derived from 1-adamantyl (meth)acrylate, diamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, and cyclohexyl (meth)acrylate.
The resin (A) may have a repeating unit represented by formula (III) and having no hydroxy group and no cyano group.
In formula (III), R5 represents a hydrocarbon group having at least one ring structure and having no hydroxy group and no cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH2—O—Ra2 group. In this formula, Ra2 represents a hydrogen atom, an alkyl group, or an acyl group.
Examples of the repeating unit represented by formula (III) and having no hydroxy group and no cyano group include those described in paragraphs [0087] to [0094] of JP2014-098921A.
The resin (A) may further have an additional repeating unit other than the repeating units described above.
For example, the resin (A) may have a repeating unit selected from the group consisting of a repeating unit having an oxathiane ring group, a repeating unit having an oxazolone ring group, a repeating unit having a dioxane ring group, and a repeating unit having a hydantoin ring group.
Specific examples of the additional repeating unit other than the repeating units described above are shown below.
The resin (A) may have, in addition to the repeating units described above, various repeating units for the purpose of controlling dry etching resistance, suitability for a standard developer, adhesiveness to a substrate, a resist profile, resolution, heat resistance, sensitivity, etc.
Preferably, in the resin (A), especially when the composition is used as an actinic ray-sensitive or radiation-sensitive resin composition for ArF light, all the repeating units are composed of repeating units derived from compounds having an ethylenically unsaturated bond.
The resin (A) can be synthesized by a routine method (for example, radical polymerization).
The weight average molecular weight of the resin (A) that is determined as a polystyrene-equivalent value by the GPC method is preferably 30,000 or less, more preferably 1,000 to 30,000, still more preferably 3,000 to 30,000, and particularly preferably 5,000 to 15,000.
The dispersity (molecular weight distribution) of the resin (A) is preferably 1 to 5, more preferably 1 to 3, still more preferably 1.2 to 3.0, and particularly preferably 1.2 to 2.0. The smaller the dispersity, the better the resolution and the resist profile, and the smoother the side surfaces of the resist pattern, so that better roughness quality is obtained.
In the composition of the invention, the content of the resin (A) with respect to the total mass of the solids in the composition is preferably 40.0 to 99.9% by mass, more preferably 50.0 to 95.0% by mass, and still more preferably 60.0 to 90.0% by mass.
One resin (A) may be used alone, or a combination of a plurality of resins (A) may be used.
The composition of the invention includes a compound that generates an acid upon irradiation with actinic rays or radiation (this compound is referred to also as a photoacid generator (B)).
The photoacid generator (B) may be in the form of a low-molecular weight compound or may be in the form in which the photoacid generator (B) is incorporated into part of a polymer (e.g., the resin (A) described above). A combination of the form of a low-molecular-weight compound and the form in which the photoacid generator (B) is incorporated into part of a polymer (e.g., the resin (A) described above) may also be used.
When the photoacid generator (B) is in the form of a low-molecular weight compound, the molecular weight of the photoacid generator is preferably 3000 or less, more preferably 2000 or less, and still more preferably 1000 or less. No particular limitation is imposed on the lower limit of the molecular weight, but the molecular weight is 100 or more.
When the photoacid generator (B) is in the form in which the photoacid generator (B) is incorporated into part of a polymer, the photoacid generator (B) may be incorporated into part of the resin (A) or into a resin different from the resin (A).
In the present specification, it is preferable that the photoacid generator (B) is in the form of a low-molecular weight compound.
The photoacid generator (B) is, for example, a compound (onium salt) represented by “M+X−” and is preferably a compound that generates an organic acid upon exposure to light.
Examples of the organic acid include sulfonic acids (such as aliphatic sulfonic acids, aromatic sulfonic acids, and camphorsulfonic acid), carboxylic acids (such as aliphatic carboxylic acids, aromatic carboxylic acids, and aralkyl carboxylic acids), carbonylsulfonylimidic acid, bis(alkylsulfonyl)imidic acids, and tris(alkylsulfonyl)methide acids.
In the compound represented by “M+X−,” M+ represents an organic cation.
No particular limitation is imposed on the organic cation. The valence of the organic cation may be 1 or two or more.
In particular, the organic cation is preferably a cation represented by formula (ZaI) (hereinafter referred to as a “cation (ZaI)”) or a cation represented by formula (ZaII) (hereinafter referred to as a “cation (ZaII)”).
In formula (ZaI) above, R201, R202, and R203 each independently represent an organic group.
The number of carbon atoms in each of the organic groups used as R201, R202, and R203 is preferably 1 to 30 and more preferably 1 to 20. Two selected from the group consisting of R201 to R203 may be bonded together to form a ring structure, and the ring may include an oxygen atom, a sulfur atom, an ester group, an amido group, or a carbonyl group. Examples of the group formed from two selected from the group consisting of R201 to R203 that are bonded together include alkylene groups (such as a butylene group and a pentylene group) and —CH2—CH2—O—CH2—CH2—.
Preferred examples of the form of the organic cation in formula (ZaI) include a cation (ZaI-1), a cation (ZaI-2), a cation (ZaI-3b), and a cation (ZaI-4b) that will be described later.
First, the cation (ZaI-1) will be described.
The cation (ZaI-1) is an arylsulfonium cation in which at least one of R201, R202, or R203 in formula (ZaI) is an aryl group.
In the arylsulfonium cation, each of R201 to R203 may be an aryl group. Alternatively, some of R201 to R203 may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.
Alternatively, one of R201, R202, or R203 may be an aryl group, and the remaining two of R201 to R203 may be bonded together to form a ring structure. The ring may include an oxygen atom, a sulfur atom, an ester group, an amido group, or a carbonyl group. Examples of the group formed by bonding two selected from the group consisting of R201 to R203 together include alkylene groups in which at least one methylene group is optionally replaced with an oxygen atom, a sulfur atom, an ester group, an amido group, and/or a carbonyl group (such as a butylene group, a pentylene group, and a —CH2—CH2—O—CH2—CH2—).
Examples of the arylsulfonium cation include triarylsulfonium cations, diarylalkylsulfonium cations, aryldialkylsulfonium cations, diarylcycloalkylsulfonium cations, and aryldicycloalkylsulfonium cations.
Each aryl group included in the arylsulfonium cation is preferably a phenyl group or a naphthyl group and is more preferably a phenyl group. The aryl group may have a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, etc. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue. When the arylsulfonium cation has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group or the cycloalkyl group optionally included in the arylsulfonium cation is preferably a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or a cycloalkyl group having 3 to 15 carbon atoms and more preferably a methyl group, an ethyl group, a propyl group, a n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, or a cyclohexyl group.
The aryl, alkyl, and cycloalkyl groups in R201 to R203 may each have a substituent, and the substituent is preferably an alkyl group (having, for example, 1 to 15 carbon atoms), a cycloalkyl group (having, for example, 3 to 15 carbon atoms), an aryl group (having, for example, 6 to 14 carbon atoms), an alkoxy group (having, for example, 1 to 15 carbon atoms), a cycloalkylalkoxy group (having, for example, 1 to 15 carbon atoms), a halogen atom (for example, fluorine or iodine), a hydroxy group, a carboxy group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, or a phenylthio group.
Each substituent may have a substituent if possible. It is also preferable that the alkyl group has a halogen atom as a substituent and is therefore a halogenated alkyl group such as a trifluoromethyl group.
It is also preferable that any of these substituents are combined together to form an acid-decomposable group.
The acid-decomposable group means a group that is decomposed by the action of an acid to generate a polar group and has preferably a structure in which the polar group is protected by a group that leaves by the action of an acid.
The polar group is preferably an alkali-soluble group, and examples thereof include: acidic groups such as a carboxy group, phenolic hydroxy groups, fluorinated alcohol groups, sulfonic acid groups, phosphoric acid groups, sulfonamido groups, sulfonylimido groups, (alkylsulfonyl)(alkylcarbonyl)methylene groups, (alkylsulfonyl)(alkylcarbonyl)imido groups, bis(alkylcarbonyl)methylene groups, bis(alkylcarbonyl)imido groups, bis(alkylsulfonyl)methylene groups, bis(alkylsulfonyl)imido groups, tris(alkylcarbonyl)methylene groups, and tris(alkylsulfonyl)methylene groups; and alcoholic hydroxy groups.
In particular, the polar group is preferably a carboxy group, a phenolic hydroxy group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), or a sulfonic acid group.
Examples of the group that leaves by the action of an acid include groups represented by formulas (Y1) to (Y4).
In formulas (Y1) and (Y2), Rx1 to Rx3 each independently represent an alkyl group (linear or branched alkyl group), a cycloalkyl group (monocyclic or polycyclic cycloalkyl group), an alkenyl group (linear or branched alkenyl group), or an aryl group (monocyclic or polycyclic aryl group). When all of Rx1 to Rx3 are alkyl groups (linear or branched alkyl groups), it is preferable that at least two selected from the group consisting of Rx1 to Rx3 are each a methyl group.
In particular, it is preferable that Rx1 to Rx3 each independently represent a linear or branched alkyl group, and it is more preferable that Rx1 to Rx3 each independently represent a linear alkyl group.
Two selected from the group consisting of Rx1 to Rx3 may be bonded together to form a monocyclic or polycyclic ring.
In formula (Y3), R36 to R38 each independently represent a hydrogen atom or a monovalent organic group. R37 and R38 may be bonded together to form a ring. Examples of the monovalent organic group include alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, and alkenyl groups. It is also preferable that R36 is a hydrogen atom.
The alkyl, cycloalkyl, aryl, and aralkyl groups described above may each include a heteroatom such as an oxygen atom and/or a group including a heteroatom such as a carbonyl group. For example, in the alkyl, cycloalkyl, aryl, and aralkyl groups described above, at least one methylene group may be replaced with a heteroatom such as an oxygen atom and/or a group including a heteroatom such as a carbonyl group.
R38 may be bonded to another substituent included in the main chain of the repeating unit to form a ring. The group formed by bonding R38 and another substituent included in the main chain of the repeating unit is preferably an alkylene group such as a methylene group.
When the resist composition is, for example, a resist composition for EUV exposure, it is also preferable that the monovalent organic groups represented by R36 to R38 and the group formed by bonding R37 and R38 together each further have a fluorine atom or an iodine atom as a substituent.
In formula (Y4), Ar represents an aromatic ring group. Rn represents an alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may be bonded together to form a non-aromatic ring. Ar is preferably an aryl group.
When the resist composition is, for example, a resist composition for EUV exposure, it is also preferable that the aromatic ring group represented by Ar and the alkyl, cycloalkyl, or aryl group represented by Rn each have a fluorine atom or an iodine atom as a substituent.
Next, the cation (ZaI-2) will be described.
The cation (ZaI-2) is a cation in which R201 to R203 in formula (ZaI) each independently represent an organic group having no aromatic ring. The aromatic ring is intended to encompass an aromatic ring including a heteroatom.
The number of carbon atoms in each of the organic groups having no aromatic ring and represented by R201 to R203 is preferably 1 to 30 and more preferably 1 to 20.
R201 to R203 are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and still more preferably a linear or branched 2-oxoalkyl group.
Examples of the alkyl and cycloalkyl groups in R201 to R203 include: linear alkyl groups having 1 to 10 carbon atoms and branched alkyl groups having 3 to 10 carbon atoms (such as a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group); and cycloalkyl groups having 3 to 10 carbon atoms (such as a cyclopentyl group, a cyclohexyl group, and a norbornyl group).
R201 to R203 may each be further substituted with a halogen atom, an alkoxy group (having, for example, 1 to 5 carbon atoms), a hydroxy group, a cyano group, or a nitro group.
It is also preferable that the substituents in R201 to R203 are each independently combined with another substituent to form an acid-decomposable group.
Next, the cation (ZaI-3b) will be described.
The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).
In formula (ZaI-3b), R1c to R5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxy group, a nitro group, an alkylthio group, or an arylthio group.
R6c and R7c each independently represent a hydrogen atom, an alkyl group (such as a t-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group.
Rx and Ry each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.
R1c to R7c, Rx, and Ry may each have a substituent, and it is also preferable that these substituents are each independently combined with another substituent to form an acid-decomposable group.
A combination of two or more selected from the group consisting of R1c to R5c, a pair of R5c and R6c, a pair of R6c and R7c, a pair of R5c and Rx, and a pair of Rx and Ry may each be bonded together to form a ring. These rings may each independently include an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond.
Each ring may be an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocyclic ring, or a polycyclic condensed ring formed by combining two or more of the above rings. The ring may be a 3- to 10-membered ring and is preferably a 4- to 8-membered ring and more preferably a 5- or 6-membered ring.
Examples of the groups formed by bonding two or more selected from the group consisting of R1c to R5c, bonding R6c and R7c, and bonding Rx and Ry include alkylene groups such as a butylene group and a pentylene group. A methylene group in the alkylene group may be replaced with a heteroatom such as an oxygen atom.
The group formed by bonding R5c and R6c and the group formed by bonding R5c and Rx are each preferably a single bond or an alkylene group. Examples of the alkylene group include a methylene group and an ethylene group.
R1c to R5c, R6c, R7c, Rx, Ry, the ring formed by bonding together a combination of two or more selected from the group consisting of R1c to R5c, the ring formed by bonding together a pair of R5c and R6c, the ring formed by bonding together a pair of R6c and R7c, the ring formed by bonding together a pair of R5c and Rx, and the ring formed by bonding together a pair of Rx and Ry may each have a substituent.
Next, the cation (ZaI-4b) will be described.
The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).
In formula (ZaI-4b), 1 represents an integer of from 0 to 2, and r represents an integer of from 0 to 8.
R13 represents a hydrogen atom, a halogen atom (such as a fluorine atom or an iodine atom), a hydroxy group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxy group, an alkoxycarbonyl group, or a group including a cycloalkyl group (a cycloalkyl group itself or a group including a cycloalkyl group as a part thereof). These groups may each have a substituent.
R14 represents a hydroxy group, a halogen atom (such as a fluorine atom or an iodine atom), an alkyl group, a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group including a cycloalkyl group (a cycloalkyl group itself or a group including a cycloalkyl group as a part thereof). These groups may each have a substituent. When a plurality of R14s is present, they each independently represent any of the above groups such as a hydroxy group.
R15's each independently represent an alkyl group, a cycloalkyl group, or a naphthyl group. The two R15s may be bonded together to form a ring. When the two R15s are bonded together to form a ring, the skeleton of the ring may include a heteroatom such as an oxygen atom or a nitrogen atom.
In one preferred mode, the two R15s are each an alkylene group and are bonded together to form a ring structure. The above alkyl, cycloalkyl, and naphthyl groups and the ring formed by bonding the two R15's together may each have a substituent.
In formula (ZaI-4b), the alkyl group represented by each of R13, R14, and R15s may be a linear or branched alkyl group. Preferably, the number of carbon atoms in the alkyl group is 1 to 10. Each alkyl group is preferably a methyl group, an ethyl group, a n-butyl group, a t-butyl group, etc.
It is also preferable that the substituents in R13 to R15, Rx, and Ry are each independently combined with another substituent to form an acid-decomposable group.
Next, formula (ZaII) will be described.
In formula (ZaII), R204 and R205 each independently represent an aryl group, an alkyl group, or a cycloalkyl group.
The aryl group represented by each of R204 and R205 is preferably a phenyl group or a naphthyl group and more preferably a phenyl group. The aryl group represented by each of R204 and R205 may be an aryl group having a heterocycle having an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the skeleton of the aryl group having a heterocycle include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
The alkyl or cycloalkyl group represented by each of R204 and R205 is preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (such as a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group) or is a cycloalkyl group having 3 to 10 carbon atoms (such as a cyclopentyl group, a cyclohexyl group, or a norbornyl group).
The aryl, alkyl, and cycloalkyl groups represented by R204 and R205 may each independently have a substituent. Examples of the optional substituents in the aryl, alkyl, and cycloalkyl groups represented by R204 and R205 include alkyl groups (having, for example, 1 to 15 carbon atoms), cycloalkyl groups (having, for example, 3 to 15 carbon atoms), aryl groups (having, for example, 6 to 15 carbon atoms), alkoxy groups (having, for example, 1 to 15 carbon atoms), halogen atoms, a hydroxy group, and a phenylthio group. It is also preferable that the substituents in R204 and R205 are each independently combined with another substituent to form an acid-decomposable group.
Specific examples of the organic cation are shown below. However, the invention is not limited thereto.
In the compound represented by “M+X−,” X− represents an organic anion.
No particular limitation is imposed on the organic anion, and examples thereof include monovalent organic anions and divalent and higher valent organic anions.
The organic anion is preferably an anion whose ability to cause a nucleophilic reaction is very low and is more preferably a non-nucleophilic anion.
Examples of the non-nucleophilic anion include sulfonate anions (such as aliphatic sulfonate anions, aromatic sulfonate anions, and a camphorsulfonate anion), carboxylate anions (such as aliphatic carboxylate anions, aromatic carboxylate anions, and aralkyl carboxylate anions), sulfonylimide anions, bis(alkylsulfonyl)imide anions, and tris(alkylsulfonyl)methide anions.
In the aliphatic sulfonate anions and the aliphatic carboxylate anions, the aliphatic moiety may be a linear or branched alkyl group or a cycloalkyl group and is preferably a linear or branched alkyl group having 1 to 30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.
The alkyl group may be, for example, a fluoroalkyl group (which may have a substituent other than a fluorine atom or may be a perfluoroalkyl group).
In the aromatic sulfonate anions and the aromatic carboxylate anions, the aryl group is preferably an aryl group having 6 to 14 carbon atoms such as a phenyl group, a tolyl group, or a naphthyl group.
The above-described alkyl, cycloalkyl, and aryl groups may each have a substituent. No particular limitation is imposed on the substituent, and examples thereof include a nitro group, halogen atoms such as a fluorine atom and a chlorine atom, a carboxy group, a hydroxy group, an amino group, a cyano group, alkoxy groups (having preferably 1 to 15 carbon atoms), alkyl groups (having preferably 1 to 10 carbon atoms), cycloalkyl groups (having preferably 3 to 15 carbon atoms), aryl groups (having preferably 6 to 14 carbon atoms), alkoxycarbonyl groups (having preferably 2 to 7 carbon atoms), acyl groups (having preferably 2 to 12 carbon atoms), alkoxycarbonyloxy groups (having preferably 2 to 7 carbon atoms), alkylthio groups (having preferably 1 to 15 carbon atoms), alkylsulfonyl groups (having preferably 1 to 15 carbon atoms), alkyliminosulfonyl groups (having preferably 1 to 15 carbon atoms), and aryloxysulfonyl groups (having preferably 6 to 20 carbon atoms).
In the aralkyl carboxylate anions, the aralkyl group is preferably an aralkyl group having 7 to 14 carbon atoms.
Examples of the aralkyl group having 7 to 14 carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylbutyl group.
Examples of the sulfonylimide anion include a saccharin anion.
In the bis(alkylsulfonyl)imide anions and the tris(alkylsulfonyl)methide anions, the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. These alkyl groups may have a substituent, and examples of the substituent include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, and cycloalkylaryloxysulfonyl groups. The substituent is preferably a fluorine atom or an alkyl group substituted with a fluorine atom.
In the bis(alkylsulfonyl)imide anions, the alkyl groups may be bonded together to form a ring structure. In this case, the strength of the acid increases.
Other examples of the non-nucleophilic anion include phosphorus fluoride (such as PF6), boron fluoride (such as BF4−), and antimony fluoride (such as SbF6−).
The non-nucleophilic anion is preferably an aliphatic sulfonate anion substituted with a fluorine atom at least at the α-position of the sulfonic acid, an aromatic sulfonate anion substituted with a fluorine atom or a fluorine atom-containing group, a bis(alkylsulfonyl)imide anion in which an alkyl group is substituted with a fluorine atom, or a tris(alkylsulfonyl)methide anion in which an alkyl group is substituted with a fluorine atom. In particular, the non-nucleophilic anion is more preferably a perfluoroaliphatic sulfonate anion (having preferably 4 to 8 carbon atoms) or a benzenesulfonate anion having a fluorine atom and still more preferably a nonafluorobutanesulfonate anion, a perfluorooctanesulfonate anion, a pentafluorobenzenesulfonate anion, or a 3,5-bis(trifluoromethyl)benzenesulfonate anion.
The non-nucleophilic anion is also preferably an anion represented by the following formula (AN1).
In formula (AN1), R1 and R2 each independently represent a hydrogen atom or a substituent.
No particular limitation is imposed on the substituent, but the substituent is preferably a group other than electron-withdrawing groups. Example of the group other than electron-withdrawing groups include hydrocarbon groups, a hydroxy group, oxyhydrocarbon groups, oxycarbonyl hydrocarbon groups, an amino group, hydrocarbon-substituted amino groups, and hydrocarbon-substituted amido groups.
Preferably, these groups other than electron-withdrawing groups are each independently —R′, —OH, —OR′, —OCOR′, —NH2, —NR′2, —NHR′, or —NHCOR′. R′ is a monovalent hydrocarbon group.
Examples of the monovalent hydrocarbon group represented by R′ include: linear or branched monovalent hydrocarbon groups including alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group, alkenyl groups such as an ethenyl group, a propenyl group, and a butenyl group, and alkynyl groups such as an ethynyl group, a propynyl group, and a butynyl group; monovalent alicyclic hydrocarbon groups including cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and a adamantyl group and cycloalkenyl groups such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, and a norbornenyl group; and monovalent aromatic hydrocarbon groups including aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, a methylnaphthyl group, an anthryl group, and a methylanthryl group and aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group, and an anthrylmethyl group.
In particular, it is preferable that R1 and R2 each independently represent a hydrocarbon group (preferably a cycloalkyl group) or a hydrogen atom.
L represents a divalent linking group.
When a plurality of Ls is present, they may be the same or different.
Examples of the divalent linking group include —O—CO—O—, —COO—, —CONH—, —CO—, —O—, —S—, —SO—, —SO2—, alkylene groups (having preferably 1 to 6 carbon atoms), cycloalkylene groups (having preferably 3 to 15 carbon atoms), alkenylene groups (having preferably 2 to 6 carbon atoms), and divalent linking groups formed by combining any of these groups. In particular, the divalent linking group is preferably —O—CO—O—, —COO—, —CONH—, —CO—, —O—, —SO2—, —O—CO—O-alkylene group-, —COO-alkylene group-, or —CONH-alkylene group- and more preferably —O—CO—O—, —O—CO—O-alkylene group-, —COO—, —CONH—, —SO2—, or —COO-alkylene group-.
Preferably, L is, for example, a group represented by the following formula (AN1-1).
*a—(CR2a2)X-Q-(CR2b2)Y*b (AN1-1)
In formula (AN1-1), *a represents a bonding position to R3 in formula (AN1).
*b represents a bonding position to —C(R1)(R2)— in formula (AN1).
X and Y each independently represent an integer of from 0 to 10 and preferably an integer of from 0 to 3.
R2a and R2b each independently represent a hydrogen atom or a substituent.
When a plurality of R2as is present, they may be the same or different. When a plurality of R2bs is present, they may be the same or different.
When Y is 1 or more, R2b in CR2b2 that is bonded directly to —C(R1)(R2)— in formula (AN1) differs from a fluorine atom.
Q represents *A—O—CO—O—*B, *A—CO—*B, *A—CO—O—*B, *A—O—CO—*B, *A—O—*B, *A—S—*B, or *A—SO2—*B.
When X+Y in formula (AN1-1) is 1 or more and R2a's and R2b's in formula (AN1-1) are each a hydrogen atom, and Q represents *A—O—CO—O—*B, *A—CO—*B, *A—O—CO—*B, *A—O—*B, *A—S—*B, *A—SO2—*B.
*A represents a bonding position on the R3 side in formula (AN1), and *B represents a bonding position on the —SO3− side in formula (AN1).
In formula (AN1), R3 represents an organic group.
No particular limitation is imposed on the organic group, so long as it has at least one carbon atom. The organic group may be a linear group (e.g., a linear alkyl group), a branched group (e.g., a branched alkyl group such as a t-butyl group), or a cyclic group. The organic group may or may not have a substituent. The organic group may or may not have a heteroatom (such as an oxygen atom, a sulfur atom, and/or a nitrogen atom).
In particular, R3 is preferably an organic group having a ring structure. The ring structure may be a monocyclic structure or a polycyclic structure and may have a substituent. Preferably, the ring in the organic group including the ring structure is bonded directly to L in formula (AN1).
The organic group having the ring structure may or may not have, for example, a heteroatom (for example, an oxygen atom, a sulfur atom, and/or, a nitrogen atom). At least one carbon atom included in the ring structure may be replaced with a heteroatom.
The organic group having the ring structure is preferably a hydrocarbon group having a ring structure, a lactone ring group, or a sultone ring group. In particular, the organic group having the ring structure is preferably a hydrocarbon group having a ring structure.
The hydrocarbon group having a ring structure is preferably a monocyclic or polycyclic cycloalkyl group. These groups may have a substituent.
The cycloalkyl group may be a monocyclic group (such as a cyclohexyl group) or a polycyclic group (such as an adamantyl group), and the number of carbon atoms is preferably 5 to 12.
Preferably, the lactone group and the sultone group are each, for example, a group formed by removing one hydrogen atom from a ring member atom included in the lactone or sultone structure in any of the structures represented by formulas (LC1-1) to (LC1-21) and formulas (SL1-1) to (SL1-3) described above.
The non-nucleophilic anion may be a benzenesulfonate anion and is preferably a benzenesulfonate anion substituted with a branched alkyl group or a cycloalkyl group.
The non-nucleophilic anion is also preferably an anion represented by the following formula (AN2).
In formula (AN2), o represents an integer of from 1 to 3. p represents an integer of from 0 to 10. q represents an integer of from 0 to 10.
Xf's each represent a hydrogen atom, a fluorine atom, an alkyl group substituted with at least one fluorine atom, or an organic group having no fluorine atom. The number of carbon atoms in the alkyl group is preferably 1 to 10 and more preferably 1 to 4. The alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.
Xf's are each preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms and more preferably a fluorine atom or CF3. It is still more preferable that each of Xf's is a fluorine atom.
R4 and R5 each independently represent a hydrogen atom, a fluorine atom, an alkyl group, or an alkyl group substituted with at least one fluorine atom. When a plurality of R4s is present, they may be the same or different. When a plurality of R5s is present, they may be the same or different.
The number of carbon atoms in each of the alkyl groups represented by R4 and R5 is preferably 1 to 4. Each alkyl group may have a substituent. R4 and R5 are each preferably a hydrogen atom.
L represents a divalent linking group. The definition of L is the same as the definition of L in formula (AN1).
W represents an organic group including a ring structure. In particular, W is preferably a cyclic organic group.
Examples of the cyclic organic group include alicyclic groups, aryl groups, and heterocyclic groups.
The alicyclic group may be a monocyclic alicyclic group or a polycyclic alicyclic group. Examples of the monocyclic alicyclic group include monocyclic cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic group include polycyclic cycloalkyl groups such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Of these, alicyclic groups having 7 or more carbon atoms and a bulky structure such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferred.
The aryl group may be a monocyclic or polycyclic aryl group. Examples of such an aryl group include a phenyl group, a naphthyl group, a phenanthryl group, and an anthryl group.
The heterocyclic group may be a monocyclic or polycyclic heterocyclic group. In particular, when the heterocyclic group is a polycyclic heterocyclic group, diffusion of acid can be further reduced. The heterocyclic group may or may not have aromaticity. Examples of the heterocycle having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Examples of the heterocycle having no aromaticity include a tetrahydropyran ring, lactone rings, sultone rings, and a decahydroisoquinoline ring. The heterocycle in the heterocyclic group is preferably a furan ring, a thiophene ring, a pyridine ring, or a decahydroisoquinoline ring.
The above cyclic organic group may have a substituent. Examples of the substituent include alkyl groups (which may be linear or branched and have preferably 1 to 12 carbon atoms), cycloalkyl groups (which may be monocyclic, polycyclic, or spirocyclic and have preferably 3 to 20 carbon atoms), aryl groups (having preferably 6 to 14 carbon atoms), a hydroxy group, alkoxy groups, ester groups, amido groups, urethane groups, ureide groups, thioether groups, sulfonamido groups, and sulfonate groups. Carbon included in the cyclic organic group (carbon contributing to the formation of the ring) may be carbonyl carbon.
The anion represented by formula (AN2) is preferably SO3−—CF2—CH2—OCO-(L)q′-W, SO3−—CF2—CHF—CH2—OCO-(L)q′-W, SO3−—CF2—COO-(L)q′-W, SO3−—CF2—CF2—CH2—CH2-(L)q-W, or SO3−—CF2—CH(CF3)—OCO-(L)q′-W. L, q, and W are the same as those in formula (AN2). q′ represents an integer of from 0 to 10.
The non-nucleophilic anion is also preferably an aromatic sulfonate anion represented by the following formula (AN3).
In formula (AN3), Ar represents an aryl group (such as a phenyl group) and may further have a substituent other than a sulfonate anion and the -(D-B) group. Examples of the substituent include a fluorine atom and a hydroxy group.
n represents an integer of 0 or more. n is preferably 1 to 4, more preferably 2 to 3, and still more preferably 3.
D represents a single bond or a divalent linking group. Examples of the divalent linking group include ether groups, thioether groups, a carbonyl group, sulfoxide groups, a sulfone group, sulfonate groups, ester groups, and groups formed by combining two or more of these groups.
B represents a hydrocarbon group.
B is preferably an aliphatic hydrocarbon group and more preferably an isopropyl group, a cyclohexyl group, or an aryl group optionally having a substituent (such as a tricyclohexylphenyl group).
The non-nucleophilic anion is also preferably a disulfonamide anion.
The disulfonamide anion is, for example, an anion represented by N−(SO2—Rq)2.
Here, Rq represents an alkyl group optionally having a substituent and is preferably a fluoroalkyl group and more preferably a perfluoroalkyl group. Two Rqs may be bonded together to form a ring. The group formed by bonding two Rqs is preferably an alkylene group optionally having a substituent, more preferably a fluoroalkylene group, and still more preferably a perfluoroalkylene group. The number of carbon atoms in the alkylene group is preferably 2 to 4.
Other examples of the non-nucleophilic anion include anions represented by the following formulas (d1-1) to (d1-4).
In formula (d1-1), R51 represents a hydrocarbon group (e.g., an aryl group such as a phenyl group) optionally having a substituent (e.g., a hydroxy group).
In formula (d1-2), Z2c represents a hydrocarbon group having 1 to 30 carbon atoms and optionally having a substituent (provided that the carbon atom adjacent to S is not substituted with a fluorine atom).
The hydrocarbon group represented by Z2c may be linear or branched and may have a ring structure. A carbon atom in the hydrocarbon group (preferably, a carbon atom serving as a ring member atom when the hydrocarbon group has a ring structure) may be carbonyl carbon (—CO—). Examples of the hydrocarbon group include a group having a norbornyl group optionally having a substituent. A carbon atom included in the norbornyl group may be carbonyl carbon.
It is preferable that “Z2c—SO3−” in formula (d1-2) differs from the anions represented by formulas (AN1) to (AN3) above. For example, Z2c differs from an aryl group. For example, in Z2c, the atoms at the α- and β-positions with respect to —SO3− are each preferably an atom different from a carbon atom having a fluorine atom as a substituent. For example, in Z2c, the atom at the α-position and/or the atom at the β-position with respect to —SO3− is preferably a ring member atom of the cyclic group.
In formula (d1-3), R52 represents an organic group (preferably a hydrocarbon group having a fluorine atom), and Y3 represents a linear, branched, or cyclic alkylene group, an arylene group, or a carbonyl group. Rf represents a hydrocarbon group.
In formula (d1-4), R53 and R54 each independently represent an organic group (preferably a hydrocarbon group having a fluorine atom). R53 and R54 may be bonded together to form a ring.
One type of organic anion may be used alone, or two or more types of organic anions may be used.
It is also preferable that the photoacid generator includes at least one selected from the group consisting of compounds (I) to (II).
In one preferred mode, the photoacid generator is at least one selected from the group consisting of the compounds (I) to (II).
The compound (I) is a compound having at least one structural moiety Z1 described below and at least one structural moiety Z2 described below and is a compound that generates an acid including a first acidic moiety described below and derived from the structural moiety Z1 and a second acidic moiety described below and derived from the structural moiety Z2 upon irradiation with actinic rays or radiation.
Structural moiety Z1: A structural moiety including an anionic moiety A1− and a cationic moiety M1+ and forms the first acidic moiety represented by HA1 upon irradiation with actinic rays or radiation.
Structural moiety Z2: A structural moiety including an anionic moiety A2− and a cationic moiety M2+ and forms the second acidic moiety represented by HA2 upon irradiation with actinic rays or radiation.
The compound (I) satisfies the following condition I.
Condition I: A compound PI formed by replacing each of the cationic moiety M1+ in the structural moiety Z1 and the cationic moiety M2+ in the structural moiety Z2 in the compound (I) with H+ has an acid dissociation constant a1 derived from the first acidic moiety represented by HA1 formed by replacing the cationic moiety M1+ in the structural moiety Z1 with H+ and an acid dissociation constant a2 derived from the second acidic moiety represented by HA2 formed by replacing the cationic moiety M2+ in the structural moiety Z2 with H+, and the acid dissociation constant a2 is larger than the acid dissociation constant a1.
The condition I will be specifically described.
When the compound (I) is a compound that generates an acid having one first acidic moiety derived from the structural moiety Z1 and one second acidic moiety derived from the structural moiety Z2, the compound PI corresponds to a “compound having HA1 and HA2.”
The acid dissociation constant a1 and the acid dissociation constant a2 of this compound PI will be specifically described. When the acid dissociation constants of the compound PI are determined, the pKa when the compound PI becomes a “compound having A1− and HA2” is the acid dissociation constant a1, and the pKa when the “compound having A1− and HA2” becomes a “compound having A1− and A2−” is the acid dissociation constant a2.
When the compound (I) is, for example, a compound that generates an acid having two first acidic moieties derived from the structural moieties Z1 and one second acidic moiety derived from the structural moiety Z2, the compound PI corresponds to a “compound having two HA1s and one HA2.”
When the acid dissociation constants of the compound PI are determined, the acid dissociation constant when the compound PI becomes a “compound having one A1−, one HA1, and one HA2,” and the acid dissociation constant when the “compound having one A1−, one HA1, and one HA2” becomes a “compound having two A1−s and one HA2” each correspond to the acid dissociation constant a1. Moreover, the acid dissociation constant when the “compound having two A1−s and one HA2” becomes a “compound having two A1−s and A2−” corresponds to the acid dissociation constant a2. Specifically, the compound PT has a plurality of acid dissociation constants derived from acidic moieties represented by HA1 formed by replacing cationic moieties M1+ in the structural moieties Z1 with H+. In this case, the acid dissociation constant a2 is larger than the largest one of the plurality of acid dissociation constants a1. Let aa be the acid dissociation constant when the compound PI becomes the “compound having one A1−, one HA1, and one HA2,” and ab be the acid dissociation constant when the “compound having one A1−, one HA1, and one HA2” becomes the “compound having two A1−s and one HA2.” Then aa and ab satisfy the relation aa<ab.
The acid dissociation constants a1 and a2 are determined by the acid dissociation constant measurement method described above.
The compound PI corresponds to the acid generated when the compound (I) is irradiated with actinic rays or radiation.
When the compound (I) has two or more structural moieties Z1, these structural moieties Z1 may be the same or different. Moreover, two or more A1−s may be the same or different, and two or more M1+s may be the same or different.
In compound (I), A1− and A2− may be the same or different, and M1+ and M2+ may be the same or different. However, it is preferable that A1− and A2− are different from each other.
In the compound PI, the difference (absolute difference) between the acid dissociation constant a1 (when a plurality of acid dissociation constants a1 is present, the maximum value of the acid dissociation constants) and the acid dissociation constant a2 is preferably 0.1 or more, more preferably 0.5 or more, and still more preferably 1.0 or more. No particular limitation is imposed on the upper limit of the difference (absolute difference) between the acid dissociation constant a1 (when a plurality of acid dissociation constants a1 is present, the maximum value of the acid dissociation constants) and the acid dissociation constant a2, but the upper limit is, for example, 16 or less.
In the compound PI, the acid dissociation constant a2 is preferably 20 or less and more preferably 15 or less. The lower limit of the acid dissociation constant a2 is preferably −4.0 or more.
In the compound PI, the acid dissociation constant a1 is preferably 2.0 or less and more preferably 0 or less. The lower limit of the acid dissociation constant a1 is preferably −20.0 or more.
The anionic moiety A1− and the anionic moiety A2− are each a structural moiety including a negatively charged atom or atomic group and are each, for example, a structural moiety selected from the group consisting of formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-6) shown below.
The anionic moiety A1− is preferably a moiety capable of forming an acidic moiety having a small acid dissociation constant, more preferably a moiety represented by any one of (AA-1) to (AA-3), and still more preferably a moiety represented by any one of formulas (AA-1) and (AA-3).
The anionic moiety A2− is preferably a moiety capable of forming an acidic moiety having a larger acid dissociation constant than the anionic moiety A1−, more preferably a moiety represented by any one of formulas (BB-1) to (BB-6), and still more preferably a moiety represented by any one of formulas (BB-1) and (BB-4).
In formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-6) below, * represents a bonding position.
In formula (AA-2), RA represents a monovalent organic group. No particular limitation is imposed on the monovalent organic group represented by RA, and examples thereof include a cyano group, a trifluoromethyl group, and a methanesulfonyl group.
The cationic moiety M1+ and the cationic moiety M2+ are each a structural moiety including a positively charged atom or atomic group and are each, for example, a singly charged organic cation. Examples of the organic cation include the above-described organic cation represented by M+.
No particular limitation is imposed on the specific structure of the compound (I), and examples thereof include compounds represented by formulas (Ia-1) to (Ia-5) described below.
First, the compound represented by formula (Ia-1) will be described.
M11+A11−-L1-A12−M12+ (Ia-1)
The compound represented by formula (Ia-1) generates an acid represented by HA11-L1-A12H upon irradiation with actinic rays or radiation.
In formula (Ia-1), M11+ and M12+ each independently represent an organic cation.
A11− and A12− each independently represent a monovalent anionic functional group.
L1 represents a divalent linking group.
M11+ and M12+ may be the same or different.
A11− and A12− may be the same or different, but it is preferable that they differ from each other.
In a compound PIa (HA11-L1-A12H) formed by replacing each of the cations represented by M11+ and M12+ in formula (Ia-1) above with H+, the acid dissociation constant a2 derived from the acidic moiety represented by A12H is larger than the acid dissociation constant a1 derived from the acidic moiety represented by HA11. Preferred values of the acid dissociation constants a1 and a2 are as described above. The compound PIa is the same as the acid generated from the compound represented by formula (Ia-1) upon irradiation with actinic rays or radiation.
At least one of M11+, M12+, A11−, A12−, or L1 may have an acid-decomposable group as a substituent.
Examples of the organic cations represented by M11+ and M12+ in formula (Ia-1) include those for the organic cation represented by M+ described above.
The monovalent anionic functional group represented by A11− means a monovalent group including the anionic moiety A1− described above. The monovalent anionic functional group represented by A12− means a monovalent group including the anionic moiety A2− described above.
The monovalent anionic functional groups represented by A11− and A12− are each preferably a monovalent anionic functional group including the anionic moiety represented by any of formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-6) described above and more preferably a monovalent anionic functional group selected from the group consisting of formulas (AX-1) to (AX-3) and formulas (BX-1) to (BX-7). In particular, the monovalent anionic functional group represented by A11− is preferably a monovalent anionic functional group represented by any of formulas (AX-1) to (AX-3). In particular, the monovalent anionic functional group represented by A12− is preferably a monovalent anionic functional group represented by any of formulas (BX-1) to (BX-7) and more preferably a monovalent anionic functional group represented by any of formulas (BX-1) to (BX-6).
In formulas (AX-1) to (AX-3), RA1 and RA2 each independently represent a monovalent organic group. * represents a bonding position.
No particular limitation is imposed on the monovalent organic group represented by RA1, and examples thereof include a cyano group, a trifluoromethyl group, and a methanesulfonyl group.
The monovalent organic group represented by RA2 is preferably a linear, branched, or cyclic alkyl group or an aryl group.
The number of carbon atoms in the alkyl group is preferably 1 to 15, more preferably 1 to 10, and still more preferably 1 to 6.
The alkyl group may have a substituent. The substituent is preferably a fluorine atom or a cyano group and more preferably a fluorine atom. When the alkyl group has a fluorine atom as a substituent, the alkyl group may be a perfluoroalkyl group.
The aryl group is preferably a phenyl group or a naphthyl group and more preferably a phenyl group.
The aryl group may have a substituent. The substituent is preferably a fluorine atom, an iodine atom, a perfluoroalkyl group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), or a cyano group and is more preferably a fluorine atom, an iodine atom, or a perfluoroalkyl group.
In formulas (BX-1) to (BX-4) and (BX-6), RB represents a monovalent organic group. * represents a bonding position.
The monovalent organic group represented by RB is preferably a linear, branched, or cyclic alkyl group or an aryl group.
The number of carbon atoms in the alkyl group is preferably 1 to 15, more preferably 1 to 10, and still more preferably 1 to 6.
The alkyl group may have a substituent. No particular limitation is imposed on the substituent, but the substituent is preferably a fluorine atom or a cyano group and more preferably a fluorine atom. When the alkyl group has a fluorine atom as a substituent, the alkyl group may be a perfluoroalkyl group.
When a carbon atom in the alkyl group at a bonding position has a substituent, it is also preferable that the substituent is other than a fluorine atom and a cyano group. The carbon atom in the alkyl group at a bonding position is, for example, the carbon atom shown in the alkyl group and bonded directly to —CO— in any of formulas (BX-1) and (BX-4), the carbon atom shown in the alkyl group and bonded directly to —SO2— in any of formulas (BX-2) and (BX-3), or the carbon atom shown in the alkyl group and bonded directly to N− in formula (BX-6).
In the alkyl group, any carbon atom may be replaced with carbonyl carbon.
The aryl group is preferably a phenyl group or a naphthyl group and more preferably a phenyl group.
The aryl group may have a substituent. The substituent is preferably a fluorine atom, an iodine atom, a perfluoroalkyl group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), a cyano group, an alkyl group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), an alkoxy group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), or an alkoxycarbonyl group (for example, having preferably 2 to 10 carbon atoms and more preferably 2 to 6 carbon atoms) and more preferably a fluorine atom, an iodine atom, a perfluoroalkyl group, an alkyl group, an alkoxy group, or an alkoxycarbonyl group.
In formula (Ia-1), no particular limitation is imposed on the divalent linking group represented by L1, and examples of L1 include —CO—, —NR—, —O—, —S—, —SO—, —SO2—, alkylene groups (which may be linear or branched and have preferably 1 to 6 carbon atoms), cycloalkylene groups (having preferably 3 to 15 carbon atoms), alkenylene groups (having preferably 2 to 6 carbon atoms), divalent aliphatic heterocyclic groups (preferably 5- to 10-membered rings, more preferably 5- to 7-membered rings, and still more preferably 5- to 6-membered rings, each of which has at least one N atom, O atom, S atom, or Se atom in the ring structure), divalent aromatic heterocyclic groups (preferably 5- to 10-membered rings, more preferably 5- to 7-membered rings, and still more preferably 5- to 6-membered rings, each of which has at least one N atom, O atom, S atom, or Se atom in the ring structure), divalent aromatic hydrocarbon ring groups (preferably 6- to 10-membered rings and more preferably 6-membered rings), and divalent linking groups formed by combining a plurality of groups selected from the above groups. R is a hydrogen atom or a monovalent organic group. No particular limitation is imposed on the monovalent organic group, but the monovalent organic group is preferably, for example, an alkyl group (having preferably 1 to 6 carbon atoms).
The alkylene, cycloalkylene, alkenylene, divalent aliphatic heterocyclic, divalent aromatic heterocyclic, and divalent aromatic hydrocarbon ring groups described above may each have a substituent. Examples of the substituent include halogen atoms (preferably a fluorine atom).
In particular, the divalent linking group represented by L1 is preferably a divalent linking group represented by formula (L1).
In formula (L1), L111 represents a single bond or a divalent linking group.
No particular limitation is imposed on the divalent linking group represented by L111, and examples of the divalent linking group include —CO—, —NH—, —O—, —SO—, —SO2—, alkylene groups (which may be linear or branched and have preferably 1 to 6 carbon atoms) optionally having a substituent, cycloalkylene groups (having preferably 3 to 15 carbon atoms) optionally having a substituent, aryl groups (having preferably 6 to 10 carbon atoms) optionally having a substituent, and divalent linking groups formed by combining a plurality of groups selected from the above groups. No particular limitation is imposed on the substituent, and examples thereof include halogen atoms.
p represents an integer of from 0 to 3 and preferably represents an integer of from 1 to 3.
v represents an integer of 0 or 1.
Xf1s each independently represent a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms in the alkyl group is preferably 1 to 10 and more preferably 1 to 4. The alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.
Xf2s each independently represent a hydrogen atom, an alkyl group optionally having a fluorine atom as a substituent, or a fluorine atom. The number of carbon atoms in the alkyl group is preferably 1 to 10 and more preferably 1 to 4. In particular, each Xf2 represents preferably a fluorine atom or an alkyl group substituted with at least one fluorine atom and more preferably a fluorine atom or a perfluoroalkyl group.
In particular, Xf1's and Xf2's each independently represent preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms and more preferably a fluorine atom or CF3. In particular, it is still more preferable that Xf1's and Xf2's are each a fluorine atom.
* represents a bonding position.
When L1 in formula (Ia-1) represents a divalent linking group represented by formula (L1), it is preferable that the direct bond (*) on the L111 side in formula (L1) is bonded to A12− in formula (Ia-1).
Next, compounds represented by formulas (Ia-2) to (Ia-4) will be described.
In formula (Ia-2), A21a− and A21b− each independently represent a monovalent anionic functional group. Each of the monovalent anionic functional groups represented by A21a− and A21b− means a monovalent group including the above-described anionic moiety A1−. No particular limitation is imposed on the monovalent anionic functional groups represented by A21a− and A21b−, but A21a− and A21b− are each, for example, a monovalent anionic functional group selected from the group consisting of formulas (AX-1) to (AX-3) described above.
A22− represents a divalent anionic functional group. The divalent anionic functional group represented by A22− means a divalent linking groups including the anionic moiety A2− described above. Examples of the divalent anionic functional group represented by A22− include divalent anionic functional groups represented by the following formulas (BX-8) to (BX-11).
M21a+, M21b+, and M22+ each independently represent an organic cation. The definitions of the organic cations represented by M21a+, M21b+, and M22+ are the same as that of M11+ described above, and their preferred modes are also the same as those of M11+.
L21 and L22 each independently represent a divalent organic group.
In a compound PIa-2 formed by replacing each of the organic cations represented by M21a+, M21b+, and M22+ in formula (Ia-2) with H+, the acid dissociation constant a2 derived from an acidic moiety represented by A22H is larger than the acid dissociation constant a1-1 derived from an acidic moiety represented by A21aH and the acid dissociation constant a1-2 derived from an acidic moiety represented by A21bH. The acid dissociation constant a1-1 and the acid dissociation constant a1-2 each correspond to the acid dissociation constant a1 described above.
A21a− and A21b− may be the same or different. M21a+, M21b+, and M22+ may be the same or different.
At least one of M21a+, M21b+, M22+, A21a−, A21b−, L21, or L22 may have an acid-decomposable group as a substituent.
In formula (Ia-3), A31a− and A32− each independently represent a monovalent anionic functional group. The definition of the monovalent anionic functional group represented by A31a− is the same as those of A21a− and A21b− in formula (Ia-2), and its preferred mode is also the same as those of A21a− and A21b−.
The monovalent anionic functional group represented by A32− means a monovalent group including the anionic moiety A2− described above. No particular limitation is imposed on the monovalent anionic functional group represented by A32−, and A32− is, for example, a monovalent anionic functional group selected from the group consisting of formulas (BX-1) to (BX-7) described above.
A31b− represents a divalent anionic functional group. The divalent anionic functional group represented by A31b− means a divalent linking group including the anionic moiety A1− described above. Examples of the divalent anionic functional group represented by A31b− include a divalent anionic functional group represented by the following formula (AX-4).
M31a+, M31b+, and M32+ each independently represent a monovalent organic cation. The definitions of the organic cations represented by M31a+, M31b+, and M32+ are the same are that of M11+ described above, and their preferred modes are also the same as that of M11+.
L31 and L32 each independently represent a divalent organic group.
In a compound PIa-3 formed by replacing each of the organic cations represented by M31a+, M31b+, and M32+ in formula (Ia-3) with H+, the acid dissociation constant a2 derived from an acidic moiety represented by A32H is larger than the acid dissociation constant a1-3 derived from an acidic moiety represented by A31aH and the acid dissociation constant a1-4 derived from an acidic moiety represented by A31bH. The acid dissociation constant a1-3 and the acid dissociation constant a1-4 each correspond to the acid dissociation constant a1 described above.
A31a− and A32− may be the same or different. M31a+, M31b+, and M32+ may be the same or different.
At least one of M31a+, M31b+, M32+, A31a−, A32−, L31, or L32 may have an acid-decomposable group as a substituent.
In formula (Ia-4), A41a−, A41b−, and A42− each independently represent a monovalent anionic functional group. The definitions of the monovalent anionic functional groups represented by A41a− and A41b− are the same as the definitions of A21a− and A21b− in formula (Ia-2) described above. The definition of the monovalent anionic functional group represented by A42− is the same as that of A32− in formula (Ia-3) described above, and its preferred mode is also the same as that of A32−.
M41a+, M41b+, and M42+ each independently represent an organic cation. The definitions of the organic cations represented by M41a+, M41b+, and M42+ are the same as the definition of M11+ described above, and their preferred modes are also the same as that of M11+.
L41 represents a trivalent organic group.
In a compound PIa-4 formed by replacing each of the organic cations represented by M41a+, M41b+, and M42+ in formula (Ia-4) with H+, the acid dissociation constant a2 derived from an acidic moiety represented by A42H is larger than the acid dissociation constant a1-5 derived from an acidic moiety represented by A41aH and the acid dissociation constant a1-6 derived from an acidic moiety represented by A41bH. The acid dissociation constant a1-5 and the acid dissociation constant a1-6 each correspond to the acid dissociation constant a1 described above.
A41a−, A41b−, and A42− may be the same or different. M41a+, M41b+, and M42+ may be the same or different.
At least one of M41a+, M41b+, M42+, A41a−, A41b−, A42−, or L41 may have an acid-decomposable group as a substituent.
No particular limitation is imposed on the divalent organic groups represented by L21 and L22 in In formula (Ia-2) and L31 and L32 in formula (Ia-3), and examples thereof include —CO—, —NR—, —O—, —S—, —SO—, —SO2—, alkylene groups (which may be linear or branched and have preferably 1 to 6 carbon atoms), cycloalkylene groups (having preferably 3 to 15 carbon atoms), alkenylene groups (having preferably 2 to 6 carbon atoms), divalent aliphatic heterocyclic groups (preferably 5- to 10-membered rings, more preferably 5- to 7-membered rings, and still more preferably 5- to 6-membered rings, each of which has at least one N atom, O atom, S atom, or Se atom in the ring structure), divalent aromatic heterocyclic groups (preferably 5- to 10-membered rings, more preferably 5- to 7-membered rings, and still more preferably 5- to 6-membered rings, each of which has at least one N atom, O atom, S atom, or Se atom in the ring structure), divalent aromatic hydrocarbon ring groups (preferably 6- to 10-membered rings and more preferably 6-membered rings), and divalent organic groups formed by combining a plurality of groups selected from the above groups. Examples of R in —NR— include a hydrogen atom and monovalent organic groups. No particular limitation is imposed on the monovalent organic group, but the monovalent organic group is, for example, preferably an alkyl group (having preferably 1 to 6 carbon atoms).
The alkylene, cycloalkylene, alkenylene, divalent aliphatic heterocyclic, divalent aromatic heterocyclic, and divalent aromatic hydrocarbon ring groups described above may each have a substituent. Examples of the substituent include halogen atoms (preferably a fluorine atom).
Preferably, the divalent organic groups represented by L21 and L22 in formula (Ia-2) and L31 and L32 in formula (Ia-3) are each, for example, a divalent organic group represented by formula (L2) below.
In formula (L2). a represents an integer of from 1 to 3. * represents a bonding position.
Xf's each independently represent a fluorine atom or an alkyl group substituted with at least one fluorine atom. The number of carbon atoms in the alkyl group is preferably 1 to 10 and more preferably 1 to 4. The alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.
Xf's are each preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms and more preferably a fluorine atom or CF3. In particular, it is more preferable that both Xf's are fluorine atoms.
LA represents a single bond or a divalent linking group.
No particular limitation is imposed on the divalent linking group represented by LA, and examples thereof include —CO—, —O—, —SO—, —SO2—, alkylene groups (which may be linear or branched and have preferably 1 to 6 carbon atoms), cycloalkylene groups (having preferably 3 to 15 carbon atoms), divalent aromatic hydrocarbon ring groups (preferably 6- to 10-membered rings and more preferably 6-membered rings), and divalent linking groups formed by combining a plurality of groups selected from the above groups.
The alkylene, cycloalkylene, and divalent aromatic hydrocarbon ring groups described above may each have a substituent. Examples of the substituent include halogen atoms (preferably a fluorine atom).
Examples of the divalent organic group represented by formula (L2) include *—CF2—*, *—CF2—CF2—*, *—CF2—CF2—CF2—*, *-Ph-O—SO2—CF2—*, *-Ph-O—SO2—CF2—CF2—*, *-Ph-O—SO2—CF2—CF2—CF2—*, and *-Ph-OCO—CF2—*. Ph is a phenylene group optionally having a substituent and is preferably a 1,4-phenylene group. No particular limitation is imposed on the substituent, but the substituent is preferably an alkyl group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), an alkoxy group (for example, having preferably 1 to 10 carbon atoms and more preferably 1 to 6 carbon atoms), or an alkoxycarbonyl group (for example, having preferably 2 to 10 carbon atoms and more preferably 2 to 6 carbon atoms).
When L21 and L22 in formula (Ia-2) each represent the divalent organic group represented by formula (L2), it is preferable that the direct bond (*) on the LA side in formula (L2) is bonded to A21a− or A21b− in formula (Ia-2).
When L31 and L32 in formula (Ia-3) each represent the divalent organic group represented by formula (L2), it is preferable that the direct bond (*) on the LA side in formula (L2) is bonded to A31a− or A32− in formula (Ia-3).
Next, formula (Ia-5) will be described.
In formula (Ia-5), A51a−, A51b−, and A51c− each independently represent a monovalent anionic functional group. Each of the monovalent anionic functional groups represented by A51a−, A51b−, and A51c− means a monovalent group including the anionic moiety A1− described above. No particular limitation is imposed on the monovalent anionic functional groups represented by A51a−, A51b−, and A51c−, but each of these monovalent anionic functional groups is, for example, a monovalent anionic functional group selected from the group consisting of formulas (AX-1) to (AX-3) described above.
A52a− and A52b− each represent a divalent anionic functional group. Each of the divalent anionic functional groups represented by A52a− and A52b− means a divalent linking group including the anionic moiety A2− described above. The divalent anionic functional groups represented by A52a− and A52b− are each, for example, a divalent anionic functional groups selected from the group consisting of formulas (BX-8) to (BX-11) described above.
M51a+, M51b+, M51c+, M52a+, and M52b+ each independently represent an organic cation. The definitions of the organic cations represented by M51a+, M51b−, M51c+, M52a+, and M52b+ are the same as the definition of M11+ described above, and their preferred modes are also the same as that of M11+.
L51 and L53 each independently represent a divalent organic group. The definitions of the divalent organic groups represented by L51 and L53 are the same as those of L21 and L22 in formula (Ia-2) described above, and their preferred modes are also the same as those of L21 and L22.
L52 represents a trivalent organic group. The definition of the trivalent organic group represented by L52 is the same as that of L41 in formula (Ia-4) described above, and its preferred mode is also the same as that of L41.
In a compound PIa-5 formed by replacing each of the organic cations represented by M51a+, M51b+, M51c+, M52a+, and M52b+ in formula (Ia-5) with H+, the acid dissociation constant a2-1 derived from an acidic moiety represented by A52aH and the acid dissociation constant a2-2 derived from an acidic moiety represented by A52bH are larger than the acid dissociation constant a1-1 derived from an acidic moiety represented by A51aH, the acid dissociation constant a1-2 derived from an acidic moiety represented by A51bH, and the acid dissociation constant a1-3 derived from an acidic moiety represented by A51cH. The acid dissociation constants a1-1 to a1-3 each correspond to the acid dissociation constant a1 described above, and the acid dissociation constants a2-1 and a2-2 each correspond to the acid dissociation constant a2 described above.
A51a−, A51b−, and A51c− may be the same or different. A52a− and A52b− may be the same or different.
M51a+, M51b+, M51c+, M52a+, and M52b+ may be the same or different.
At least one of M51b+, M51c+, M52a+, M52b+, A51a−, A51b−, A51c−, L51, L52, or L53 may have an acid-decomposable group as a substituent.
The compound (II) is a compound that has two or more structural moieties Z1 described above and at least one structural moiety Z3 described below and is a compound that generates an acid including two or more first acidic moieties derived from the structural moieties Z1 and the structural moiety Z3 upon irradiation with actinic rays or radiation.
The definition of the structural moiety Z1 in the compound (II) and the definitions of A1− and M1+ are the same as that of the structural moiety Z1 in the compound (I) described above and those of A1− and M1+ in the structural moiety Z1 in the compound (I) described above, and their preferred modes are also the same as those of the compound (I).
In a compound PII formed by replacing each of the cationic moieties M1+ in the structural moieties Z1 in the compound (II) with H+, a preferred range of the acid dissociation constant a1 derived from an acidic moiety represented by HA1 formed by replacing the cationic moiety M1+ in one of the structural moieties Z1 with H+ is the same as that of the acid dissociation constant a1 in the compound PI.
When the compound (II) is, for example, a compound that generates an acid having two first acidic moieties derived from the structural moieties Z1 and the structural moiety Z3, the compound PII corresponds to a “compound having two HA1s.” When the acid dissociation constants of the compound PII are determined, the acid dissociation constant when the compound PII becomes a “compound having one A1− and one HA1” and the dissociation constant when the “compound having one A1− and one HA1” becomes a “compound having two A1−s” each correspond to the acid dissociation constant a1.
The acid dissociation constant a1 is determined by the acid dissociation constant measurement method described above.
The compound PII corresponds to an acid generated when the compound (II) is irradiated with actinic rays or radiation.
The two or more structural moieties Z1 may be the same or different. The two or more A1−'s may be the same or different, and the two or more M1+'s may be the same or different.
No particular limitation is imposed on the non-ionic moiety that is in the structural moiety Z3 and capable of neutralizing an acid, and the non-ionic moiety is, for example, preferably a moiety including a functional group having an electron or a group capable of electrostatically interacting with a proton.
Examples of the functional group having an electron or a group capable of electrostatically interacting with a proton include a functional group having a macrocyclic structure such as a cyclic polyether and a functional group having a nitrogen atom having an unshared electron pair not contributing to π-conjugation. The nitrogen atom having an unshared electron pair not contributing to π-conjugation is, for example, a nitrogen atom having a partial structure represented by any of the following formulas.
Unshared Electron Pair
Examples of the partial structure of the functional group having an electron or a group capable of electrostatically interacting with a proton include crown ether structures, azacrown ether structures, primary to tertiary amine structures, a pyridine structure, an imidazole structure, and a pyrazine structure. Of these, primary to tertiary amine structures are preferred.
No particular limitation is imposed on the compound (II), and examples thereof include compounds represented by the following formulas (IIa-1) and (IIa-2).
In formula (IIa-1), the definitions of A61a− and A61b− are each the same as that of A11− in formula (Ia-1) above, and their preferred modes are also the same as that of A11−. The definitions of M61a+ and M61b+ are each the same as that of M11+ in formula (Ia-1), and their preferred modes are also the same as that of M11+.
In formula (IIa-1), the definitions of L61 and L62 are each the same as that of L1 in formula (Ia-1) above, and their preferred modes are also the same as that of L1.
In formula (IIa-1), R2X represents a monovalent organic group. No particular limitation is imposed on the monovalent organic group represented by R2X. Examples thereof include alkyl groups (which have preferably 1 to 10 carbon atoms and may be linear or branched), cycloalkyl groups (having preferably 3 to 15 carbon atoms), and alkenyl groups (having preferably 2 to 6 carbon atoms). In the alkyl, cycloalkyl, and alkenyl groups used as the monovalent organic group represented by R2X, —CH2— may be replaced with one or a combination of two or more selected from the group consisting of —CO—, —NH—, —O—, —S—, —SO—, and —SO2—.
The above alkyl, cycloalkyl, and alkenyl groups may each have a substituent. No particular limitation is imposed on the substituent, and examples thereof include halogen atoms (preferably a fluorine atom).
In a compound PIIa-1 formed by replacing each of the organic cations represented by M61a+ and M61b+ in formula (IIa-1) with H+, the acid dissociation constant a1-7 derived from an acidic moiety represented by A61aH and the acid dissociation constant a1-8 derived from an acidic moiety represented by A61bH each correspond to the acid dissociation constant a1 described above.
The compound PIIa-1 formed by replacing each of the cationic moieties M61a+ and M61b+ in the structural moieties Z1 in formula (IIa-1) corresponds to HA61a-L61-N(R2X)-L62-A61bH. The compound PIIa-1 is the same as the acid generated from the compound represented by formula (IIa-1) upon irradiation with actinic rays or radiation.
At least one of M61a+, M61b+, A61a−, A61b−, L61, L62, or R2X may have an acid-decomposable group as a substituent.
The definitions of A71a−, A71b−, and A71c− in formula (IIa-2) are each the same as that of A11− in formula (Ia-1) above, and their preferred modes are also the same as that of A11−. The definitions of M71a+, M71b+, and M71c+ are each the same as that of M11+ in formula (Ia-1), and their preferred modes are also the same as that of M11+.
The definitions of L71, L72, and L73 in formula (IIa-2) are each the same as that of L1 in formula (Ia-1) above, and their preferred modes are also the same as that of L1.
In a compound PIIa-2 formed by replacing each of the organic cations represented by M71a+, M71b+, and M71c+ in formula (IIa-2) with H+, the acid dissociation constant a1-9 derived from an acidic moiety represented by A71aH, the acid dissociation constant a1-10 derived from an acidic moiety represented by A71bH, and the acid dissociation constant a1-11 derived from an acidic moiety represented by A71cH each correspond to the acid dissociation constant a1 described above.
The compound PIIa-2 formed by replacing each of the cationic moieties M71a+, M71b+, and M71c+ in the structural moieties Z1 in formula (IIa-2) with H+ corresponds to HA71a-L71-N(L73-A71cH)-L72-A71bH. The compound PIIa-2 is the same as the acid generated from the compound represented by formula (IIa-2) upon irradiation with actinic rays or radiation.
At least one of M71a+, M71+, M71c+, A71a−, A71b− c, A71c−, L71, L72, or L73 may have an acid-decomposable group as a substituent.
Examples of moieties that the compounds (I) and (II) can have and that differ from the cations are shown below.
Specific examples of the photoacid generator are shown below, but the photoacid generator is not limited thereto.
No particular limitation is imposed on the content of the photoacid generator (B) included in the composition of the invention. From the viewpoint of increasing the rectangularity of the cross-sectional shape of the pattern to be formed, the content of the photoacid generator (B) with respect to the total mass of the solids in the composition is preferably 0.5% by mass or more and more preferably 1.0% by mass or more. The content with respect to the total mass of the solids in the composition of the invention is preferably 60.0% by mass or less, more preferably 50.0% by mass or less, and still more preferably 40.0% by mass or less.
One photoacid generator (B) may be used alone, or two or more photoacid generators (B) may be used.
The composition of the invention may include an acid diffusion control agent.
The acid diffusion control agent functions as a quencher that traps the acid generated from the photoacid generator etc. during exposure to light to thereby suppress the reaction of the acid decomposable resin with an excess portion of the generated acid in unexposed portions.
No particular limitation is imposed on the acid diffusion control agent, and examples thereof include a basic compound (DA), a low-molecular weight compound (DB) having a nitrogen atom and having a group that leaves by the action of an acid, and a compound (DC) whose acid diffusion control ability decreases or disappears upon irradiation with actinic rays or radiation.
Examples of the compound (DC) include an onium salt compound (DD) that serves as a weak acid weaker than the photoacid generator and a basic compound (DE) whose basicity decreases or disappears upon irradiation with actinic rays or radiation.
Specific examples of the basic compound (DA) include those described in paragraphs [0132] to [0136] of WO2020/066824A, and specific examples of the basic compound (DE) whose basicity decreases or disappears upon irradiation with actinic rays or radiation include those described in paragraphs [0137] to [0155] of WO2020/066824A. Specific examples of the low-molecular weight compound (DB) having a nitrogen atom and having a group that leaves by the action of an acid include those described in paragraphs [0156] to [0163] of WO2020/066824A, and specific examples of the basic compound (DE) whose basicity decreases or disappears upon irradiation with actinic rays or radiation include those described in paragraph [0164] of WO2020/066824A.
Specific examples of the onium salt compound (DD) that serves as a weak acid weaker than the photoacid generator include those described in paragraphs [0305] to [0314] of WO2020/158337A.
In addition to the compounds described above, for example, known compounds disclosed in paragraphs [0627] to [0664] of US2016/0070167A, paragraphs [0095] to [0187] of US2015/0004544A, paragraphs [0403] to [0423] of US2016/0237190A, and paragraphs [0259] to [0328] of US2016/0274458A can be preferably used as the acid diffusion control agent.
When the composition of the invention includes the acid diffusion control agent, it is preferable from the viewpoint of the ease of trapping the acid generated in exposed portions that the composition of the invention includes an acid diffusion control agent represented by the following formula (XN).
In formula (XN), RXN represents a hydrocarbon group, and MX+ represents an organic cation.
No particular limitation is imposed on the hydrocarbon group represented by RXN. Examples of the hydrocarbon group include hydrocarbon groups having 1 to 30 carbon atoms. The hydrocarbon group may have a heteroatom, a halogen atom (such as a fluorine atom, a bromine atom, or an iodine atom), etc.
In one preferred mode, the hydrocarbon group is, for example, an alkyl group, a cycloalkyl group, or an aryl group.
The alkyl group may be linear or branched and is preferably an alkyl group having 1 to 20 carbon atoms and more preferably an alkyl group having 1 to 10 carbon atoms.
The cycloalkyl group may be monocyclic or polycyclic and is preferably a cycloalkyl group having 3 to 20 carbon atoms and more preferably a cycloalkyl group having 3 to 10 carbon atoms. At least one of the methylene groups serving as ring members of the cycloalkyl group may be replaced with an oxygen atom or a carbonyl group.
The aryl group may be monocyclic or polycyclic and is preferably an aryl group having 6 to 20 carbon atoms and more preferably an aryl group having 6 to 10 carbon atoms.
The alkyl, cycloalkyl, and aryl groups may each have an additional substituent. No particular limitation is imposed on the substituent. Examples of the additional substituent include a hydroxy group, alkyl groups (having preferably 1 to 6 carbon atoms), halogen atoms (such as a fluorine atom, a bromine atom, and an iodine atom), an arylcarbonyloxy group, and alkylcarbonyloxy groups. These groups may each have a plurality of substituents.
The alkyl, arylcarbonyloxy, and alkylcarbonyloxy groups used as the additional substituents may each further have a substituent.
The organic cation represented by MX+ is the same as M+ described above, and its preferred range is also the same as that of M+.
Specific examples of the acid diffusion control agent are shown below, but the acid diffusion control agent is not limited thereto.
When the composition of the invention includes the acid diffusion control agent, the content of the acid diffusion control agent (the total content when a plurality of acid diffusion control agents are present) with respect to the total amount of the solids in the resist composition is preferably 0.1 to 15.0% by mass and more preferably 1.0 to 15.0% by mass.
In the composition of the invention, one acid diffusion control agent may be used alone, or a combination of two or more acid diffusion control agents may be used.
The composition of the invention may further include a hydrophobic resin different from the resin (A).
Preferably, the hydrophobic resin is designed so as to segregate on the surface of a resist film. However, it is not always necessary that, unlike a surfactant, the hydrophobic resin have a hydrophilic group in its molecule and contribute to uniform mixing of polar and nonpolar substances.
The effects of the addition of the hydrophobic resin include control of the static and dynamic contact angles of water on the surface of the resist film and reduction of outgassing.
From the viewpoint of segregation of the hydrophobic resin in a surface layer of the film, the hydrophobic resin has preferably at least one of a fluorine atom, a silicon atom, or a CH3 partial structure included in a side chain portion of the resin and has more preferably two or more of them. Preferably, the hydrophobic resin has a hydrocarbon group having 5 or more carbon atoms. Each of these groups may be present as a substituent in the main chain of the resin or its side chain.
Examples of the hydrophobic resin include compounds described in paragraphs [0275] to [0279] of WO2020/004306A.
When the composition of the invention includes the hydrophobic resin, the content of the hydrophobic resin with respect to the total amount of the solids in the composition is preferably 0.01 to 20.0% by mass and more preferably 0.1 to 15.0% by mass.
The composition of the invention may include a surfactant. When the surfactant is included, the compound has better adhesiveness, and a pattern with less development defects can be formed.
The surfactant is preferably a fluorine-based surfactant and/or a silicon-based surfactant.
Examples of the fluorine-based surfactant and/or the silicon-based surfactant include surfactants disclosed in paragraphs [0218] and [0219] of WO2018/193954A.
One of these surfactants may be used alone, or two or more of them may be used.
When the composition of the invention includes the surfactant, the content of the surfactant with respect to the total amount of the solids in the resist composition is preferably 0.0001 to 2.0% by mass, more preferably 0.0005 to 1.0% by mass, and still more preferably 0.1 to 1.0% by mass.
Preferably, the composition of the invention includes a solvent.
Preferably, the solvent includes at least one of (M1) propylene glycol monoalkyl ether carboxylate or (M2) at least one selected from the group consisting of propylene glycol monoalkyl ethers, lactates, acetates, alkoxypropionates, chain ketones, cyclic ketones, lactones, and alkylene carbonates. The solvent may further include a component other than the components (M1) and (M2).
A combination of the solvent described above and the resin described above is preferably used because the coatability of the resist composition is improved and the number of development defects in a pattern is reduced. With the solvent described above, the solubility of the resin described above, the boiling point of the solvent, and its viscosity are well-balanced. Therefore, unevenness in the thickness of the resist film can be reduced, and the occurrence of precipitates during spin coating can be reduced.
The details of the components (M1) and (M2) are described in paragraphs [0218] to [0226] of WO2020/004306A, the contents of which are incorporated herein.
When the solvent further includes a component other than the components (M1) and (M2), the content of the component other than the components (M1) and (M2) with respect to the total amount of the solvent is preferably 5 to 30% by mass.
The content of the solvent in the composition of the invention is determined such that the concentration of the solids is preferably 0.5 to 30% by mass and more preferably 1 to 20% by mass. In this case, the coatability of the composition of the invention can be further improved.
The solids mean all the components other than the solvent and mean the components forming an actinic ray-sensitive or radiation-sensitive film, as described above.
The concentration of the solids is the mass percentage of the components other than the solvent with respect to the total mass of the composition of the invention.
The “total mass of the solids” is the total mass of the components of the chemical composition of the composition of the invention other than the solvent. The “solids” are the components other than the solvent as described above and are each may be a solid or a liquid at, for example, 25° C.
The composition of the invention may further include a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light absorber, and/or a compound capable of increasing the solubility in a developer (such as a phenol compound having a molecular weight of 1000 or less or an alicyclic or aliphatic compound including a carboxy group).
The “dissolution inhibiting compound” is a compound that has a molecular weight of 3000 or less and is decomposed by the action of an acid to cause the degree of solubility of the composition of the invention in an organic-based developer to decrease.
The resist composition in the present specification is preferably used as a photosensitive composition for EUV exposure.
The wavelength of the EUV light is 13.5 nm and is shorter than the wavelength of ArF light (wavelength: 193 nm) etc., and the number of incident photons when light exposure is performed at the same sensitivity is smaller. Therefore, the influence of “photon shot noise,” i.e., stochastic variations in the number of photons, is large, and this causes an increase in LER and bridge defects. One method to reduce the photon shot noise is to increase the exposure value to increase the number of incident photons, but there is a trade-off with a demand for higher sensitivity.
When the value of A determined by formula (1) is large, the efficiency of absorption of EUV light and electron beams by a resist film formed by the resist composition is high, and this is effective in reducing the photon shot noise. The value of A means the efficiency of absorption of EUV light and electron beams by a resist film having a specific mass ratio.
The value of A is preferably 0.120 or more. No particular limitation is imposed on the upper limit of the value of A. However, if the value of A is excessively large, the EUV light and electron beam transmittance of the resist film decreases, and the profile of an optical image in the resist film deteriorates, so that a good pattern shape is unlikely to be obtained. Therefore, the value of A is preferably 0.240 or less and more preferably 0.220 or less.
In formula (1), [H] represents the molar ratio of hydrogen atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids, and [C] represents the molar ratio of carbon atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids. [N] represents the molar ratio of nitrogen atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids, and [O] represents the molar ratio of oxygen atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids. [F] represents the molar ratio of fluorine atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids, and [S] represents the molar ratio of sulfur atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids. [I] represents the molar ratio of iodine atoms derived from the total solids in the actinic ray-sensitive or radiation-sensitive resin composition with respect to all the atoms in the total solids.
For example, when the resist composition includes the acid decomposable resin, the photoacid generator, the acid diffusion control agent, and the solvent, the acid decomposable resin, the photoacid generator, and the acid diffusion control agent correspond to the solids. Specifically, all the atoms in the total solids correspond to the sum of all the atoms derived from the resin, all the atoms derived from the photoacid generator, and all the atoms derived from the acid diffusion control agent.
For example, [H] represents the molar ratio of hydrogen atoms derived from the total solids with respect to all the atoms in the total solids. In the above example, [H] represents the total molar ratio of hydrogen atoms derived from the acid decomposable resin, hydrogen atoms derived from the photoacid generator, and hydrogen atoms derived from the acid diffusion control agent with respect to the sum of all the atoms derived from the acid decomposable resin, all the atoms derived from the photoacid generator, and all the atoms derived from the acid diffusion control agent.
When the structures of the constituent components of the total solids in the resist composition and their contents are known, the value of A can be computed by computing the ratio of the numbers of atoms included in the composition. Even when the constituent components are unknown, the ratio of the numbers of constituent atoms can be computed by subjecting a resist film obtained by evaporating the solvent component in the resist composition to an analytical method such as elemental analysis.
No particular limitation is imposed on the procedure of a pattern forming method using the above-described composition. Preferably, the pattern forming method includes the following steps.
The procedure of each of the steps will next be described in detail.
Step 1 is the step of forming an actinic ray-sensitive or radiation-sensitive film (preferably a resist film) on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition.
Examples of the method for forming an actinic ray-sensitive or radiation-sensitive film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition include a method in which the actinic ray-sensitive or radiation-sensitive resin composition is applied to the substrate.
Preferably, the actinic ray-sensitive or radiation-sensitive resin composition is filtrated through a filter before the application as needed. The pore size of the filter is preferably 0.1 m or less, more preferably 0.05 m or less, and still more preferably 0.03 m or less. The filer is preferably a polytetrafluoroethylene-made filter, a polyethylene-made filter, or a nylon-made filter.
The actinic ray-sensitive or radiation-sensitive resin composition can be applied to a substrate (e.g., a silicon substrate or a silicon dioxide coating) used for production of an integrated circuit element using an appropriate application method using a spinner, a coater, etc. The application method is preferably spin coating using a spinner. The number or revolutions when the spin coating using a spinner is performed is preferably 1000 to 3000 rpm.
After the application of the actinic ray-sensitive or radiation-sensitive resin composition, the substrate may be dried to thereby form the resist film. If necessary, an undercoat film (an inorganic film, an organic film, or an antireflection film) may be formed as an underlayer of the resist film.
Examples of the drying method include a method in which the substrate is heated and dried. The heating may be performed using heating means included in an ordinary exposing device and/or an ordinary developing device or may be performed using a hot plate etc. The heating temperature is preferably 80 to 150° C., more preferably 80 to 140° C., and still more preferably 80 to 130° C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, and still more preferably 60 to 600 seconds.
No particular limitation is imposed on the film thickness of the actinic ray-sensitive or radiation-sensitive film (typically a resist film), but the film thickness is preferably 10 to 120 nm because a finer pattern can be formed with higher accuracy. In particular, when actinic ray-sensitive or radiation-sensitive film is exposed to EUV light, its film thickness is more preferably 10 to 65 nm and still more preferably 15 to 50 nm. When ArF liquid immersion exposure is performed, the film thickness of the actinic ray-sensitive or radiation-sensitive film is more preferably 10 to 120 nm and still more preferably 15 to 90 nm.
A topcoat may be formed on the actinic ray-sensitive or radiation-sensitive film using a topcoat composition.
It is preferable that the topcoat composition is immiscible with the actinic ray-sensitive or radiation-sensitive film and can be uniformly applied to the upper surface of the actinic ray-sensitive or radiation-sensitive film. No particular limitation is imposed on the topcoat, and a well-known topcoat can be formed using a well-known method. For example, the topcoat can be formed using a method described in paragraphs [0072] to [0082] of JP2014-059543A.
It is preferable, for example, that a topcoat including a basic compound described in JP2013-61648A is formed on the actinic ray-sensitive or radiation-sensitive film. Specific examples of the basic compound that can be included in the topcoat include basic compounds that can be included in the resist composition.
It is also preferable that the topcoat includes a compound including at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxy group, a thiol group, a carbonyl bond, and an ester bond.
Step 2 is the step of exposing the actinic ray-sensitive or radiation-sensitive film to light.
Examples of the light exposure method include a method in which the actinic ray-sensitive or radiation-sensitive film formed is irradiated with actinic rays or radiation through a prescribed mask.
Examples of the actinic rays or radiation include infrared rays, visible rays, ultraviolet rays, far-ultraviolet rays, extreme ultraviolet rays, X rays, and electron beams. Far-ultraviolet rays having a wavelength of preferably 250 nm or shorter, more preferably 220 nm or shorter, and still more preferably 1 to 200 nm are used. Specifically, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F2 excimer laser light (157 nm), EUV light (13.5 nm), X rays, and electron beams are particularly preferred, and EUV light is most preferred.
It is preferable to perform baking (heating) after the light exposure but before development. The baking facilitates the reaction in the exposed portions, and the sensitivity and the pattern shape are further improved.
The heating temperature is preferably 80 to 150° C., more preferably 80 to 140° C., and still more preferably 80 to 130° C.
The heating time is preferably 10 to 1000 seconds, more preferably 10 to 180 seconds, and still more preferably 30 to 120 seconds.
The heating may be performed using heating means included in an ordinary exposing device and/or an ordinary developing device or may be performed using a hot plate etc.
This step is referred to as post-exposure baking.
Step 3 is the step of developing the exposed actinic ray-sensitive or radiation-sensitive film with a developer to form a pattern.
The developer may be alkali developer liquid or may be a developer including an organic solvent (hereinafter referred to as an organic-based developer) and is preferably alkali developer liquid.
Examples of the developing method include: a method in which the substrate is dipped into a bath filled with the developer for a prescribed time (a dipping method); a method in which the developer is placed on the surface of the substrate so as to bulge due to surface tension and left to stand for a prescribed time to develop the resist film (a puddle method); a method in which the developer is sprayed onto the surface of the substrate (a spraying method); and a method in which the developer is continuously discharged from a developer discharging nozzle onto the substrate rotating at a constant speed while the developer discharging nozzle is scanned at a constant speed (a dynamic dispensing method).
The step of replacing the solvent with another solvent to stop the development may be performed after the developing step.
No particular limitation is imposed on the developing time so long as the resin in unexposed portions is dissolved sufficiently, and the developing time is preferably 10 to 300 seconds and more preferably 20 to 120 seconds.
The temperature of the developer is preferably 0 to 50° C. and more preferably 15 to 35° C.
The alkali developer liquid used is preferably an aqueous alkali solution including an alkali. No particular limitation is imposed on the type of aqueous alkali solution. Examples of the aqueous alkali solution include aqueous alkali solutions including quaternary ammonium salts typified by tetramethylammonium hydroxide, inorganic alkalis, primary amines, secondary amines, tertiary amines, alcohol amines, cyclic amines, etc. In particular, the alkali developer liquid is preferably an aqueous solution of a quaternary ammonium salt typified by tetramethylammonium hydroxide (TMAH). An appropriate amount of an alcohol, a surfactant, etc. may be added to the alkali developer liquid. The alkali concentration of the alkali developer liquid is generally preferably 0.1% to 20% by mass. The pH of the alkali developer liquid is generally preferably 10.0 to 15.0.
The organic-based developer is preferably a developer including at least one organic solvent selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.
A mixture of a plurality of solvents selected from the above solvents may be used, or the organic-based developer may be mixed with water or a solvent other that the above solvents. The content of water with respect to the total mass of the developer is preferably less than 50% by mass, more preferably less than 20% by mass, and still more preferably less than 10% by mass, and it is particularly preferable that the developer includes substantially no water.
The content of the organic solvent with respect to the total mass of the organic-based developer is preferably from 50% by mass to 100% by mass inclusive, more preferably from 80% by mass to 100% by mass inclusive, still more preferably from 90% by mass to 100% by mass inclusive, and particularly preferably from 95% by mass to 100% by mass inclusive.
Preferably, the above pattern forming method further includes the step of, after step 3, washing with a rinsing solution.
Examples of the rinsing solution used in the rinsing step after the step of developing using the alkali developer liquid include pure water. An appropriate amount of a surfactant may be added to the pure water.
An appropriate amount of a surfactant may be added to the rinsing solution.
No particular limitation is imposed on the rinsing solution used for the rinsing step after the step of developing using the alkali developer so long as the rinsing solution does not dissolve the pattern, and a solution including a general-purpose organic solvent can be used. Preferably, the rinsing solution used includes at least one organic solvent selected from the group consisting of hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, and ether-based solvents.
No particular limitation is imposed on the method for the rinsing step, and examples thereof include: a method in which the rinsing solution is continuously discharged onto the substrate rotating at a constant speed (a spin coating method); a method in which the substrate is dipped into a bath filled with the rinsing solution for a prescribed time (a dipping method); and a method in which the rinsing solution is sprayed onto the surface of the substrate (a spraying method).
The pattern forming method may further include a heating (post-baking) step after the rinsing step. Through this step, the developer and the rinsing solution remaining between the patterns and inside the pattern are removed by baking. Through this step, the resist pattern is annealed, and the effect of improving surface roughness of the pattern is obtained. The heating step after the rinsing step is performed at generally 40 to 250° C. (preferably 90 to 200° C.) for generally 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).
The pattern formed may be used as a mask to perform etching treatment on the substrate. Specifically, the pattern formed in step 3 may be used as a mask to process the substrate (or the underlayer film and the substrate) to thereby form a pattern on the substrate.
No particular limitation is imposed on the method for processing the substrate (or the underlayer film and the substrate). It is preferable that the pattern formed in step 3 is used as a mask and the substrate (or the underlayer film and the substrate) is dry-etched to form a pattern on the substrate. The dry etching is preferably oxygen plasma etching.
Preferably, the composition in the present specification and various materials (such as the solvent, the developer, the rinsing solution, a composition for forming an antireflection film, and the composition for forming the topcoat) used in the pattern forming method in the present specification include no impurities such as metals. The content of the impurities included in each of these materials is preferably 1 ppm by mass or less, more preferably 10 ppb by mass or less, still more preferably 100 ppt by mass or less, particularly preferably 10 ppt by mass or less, and most preferably 1 ppt by mass or less. No particular limitation is imposed on the lower limit of the content of the impurities, and the content is preferably 0 ppt by mass or more. Examples of the metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, and Zn.
Examples of a method for removing impurities such as metals from the above materials include filtration using a filter. The details of the filtration using a filer are described in paragraph [0321] of WO2020/004306A.
Examples of a method for reducing the amount of impurities such as metals included in the above materials include: a method in which raw materials including smaller amounts of metals are used as the raw materials forming the above materials; a method in which the raw materials forming the above materials are filtrated through a filter; and a method in which distillation is performed under the condition that contamination is reduced as much as possible, for example, by coating the inside of the device used with Teflon (registered trademark).
Besides the filtration using a filter, an adsorbent may be used to remove impurities. The filtration using a filter and the absorbent may be used in combination. The adsorbent used may be a well-known adsorbent, and examples of the adsorbent that can be used include inorganic-based adsorbents such as silica gel and zeolite and organic-based adsorbents such as activated carbon. To reduce the amount of impurities such as metals included in the above materials, it is necessary to prevent the metal impurities from mixing in the production process. Whether the metal impurities have been sufficiently removed from the production device can be checked by measuring the content of metal components included in a washing solution used to clean the production device. The content of the metal components included in the washing solution after use is preferably 100 ppt (parts per trillion) by mass or less, more preferably 10 ppt by mass or less, and still more preferably 1 ppt by mass or less. No particular limitation is imposed on the lower limit of the content, and the content is preferably 0 ppt by mass or more.
An electrically conductive compound may be added to an organic treatment solution such as the rinsing solution in order to prevent failure of chemical solution pipes and various parts (such as filters, O-rings, and tubes) due to electrostatic charges and subsequent electrostatic discharge. No particular limitation is imposed on the electrically conductive compound, and examples thereof include methanol. No particular limitation is imposed on the amount of the electrically conductive compound added. From the viewpoint of maintaining preferred development characteristics or rinsing characteristics, the amount of the electrically conductive compound is preferably 10% by mass or less and more preferably 5% by mass or less. No particular limitation is imposed on the lower limit, and the amount of the electrically conductive compound is preferably 0.01% by mass or more.
The chemical solution pipes used may be, for example, SUS (stainless steel) pipes or pipes coated with antistatic-treated polyethylene, antistatic-treated polypropylene, or an antistatic-treated fluorocarbon resin (such as polytetrafluoroethylene or a perfluoroalkoxy resin). Similarly, antistatic-treated polyethylene, antistatic-treated polypropylene, or an antistatic-treated fluorocarbon resin (such as polytetrafluoroethylene or a perfluoroalkoxy resin) may be used for the filters and the O-rings.
The present specification also relates to a method for manufacturing an electronic device including the pattern forming method described above and to an electronic device manufactured by the manufacturing method.
In preferred modes of the electronic device in the present specification, the device is installed in electric and electronic devices (such as household electrical appliances and OA (Office Automation) devices, media-related devices, optical devices, and telecommunication devices).
The present invention will be further described in detail by way of Examples. Materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following Examples can be appropriately changed so long as they do not depart from the gist of the invention. Therefore, the scope of the present invention should not be construed as limited to the following Examples.
The types and contents (content ratios (molar percentage ratios)) of repeating units in resins (A) used, their weight average molecular weight (Mw), and their dispersity (Mw/Mn) are shown in Table 1-1 and Table 1-2.
The weight average molecular weight (Mw) and dispersity (Mw/Mn) of each resin (A) were measured by GPC (solvent: tetrahydrofuran (THF)). The compositional ratio (molar percentage ratio) of each resin was measured by 13C-NMR (nuclear magnetic resonance).
The structural formula of each of the repeating units shown in Table 1-1 and Table 1-2 is shown below. In the following structural formulas, * represents a direct bond.
The structures of the photoacid generators (B) used are shown below.
The structures of the acid diffusion control agents (D) used are shown below.
The compositional ratios (% by mole; one by one from left to right) of repeating units of hydrophobic resins used, their weight average molecular weight (Mw), and their dispersity (Mw/Mn) are shown below.
The weight average molecular weight (Mw) and the dispersity(Mw/Mn) of each hydrophobic resin were measured by GPC (solvent: tetrahydrofuran (THF)). The compositional ratios (% by mole) of the resins were measured by 13C-NMR (nuclear magnetic resonance).
The structural formula of each of the repeating units shown in Table 2 is shown below. For each repeating unit, the structural formula of its corresponding monomer is shown.
The following surfactants H-1 to H-4 were used.
The solvents used are shown below.
Components shown in Tables 3-1 to 3-4 were dissolved in solvents shown in Tables 3-1 to 3-4 to prepare solutions with a solid concentration of 1.6% by mass, and the solutions were filtered through polyethylene filters having a pore size of 0.02 m to prepare resist compositions.
The solids mean all the components other than the solvent. The resist compositions obtained were used for Examples and Comparative Examples.
In Tables 3-1 to 3-4 below, the content (% by mass) of each of the components other than the solvent means the content ratio with respect to the total mass of the solids. In Tables 3-1 to 3-4 below, the content ratio (% by mass) of each solvent with respect to the total mass of the solvents is shown.
A composition AL412 (manufactured by Brewer Science) for the formation of an underlayer film was applied to a silicon wafer and baked at 205° C. for 60 seconds to form an underlayer film having a film thickness of 20 nm. A resist composition in one of Examples 1 to 39 and 48 to 72 and Comparative Examples 1 to 3 shown in the table was applied to the underlayer film and baked at 100° C. for 60 seconds to form a resist film having a film thickness of 35 nm.
An EUV exposure device (Micro Exposure Tool manufactured by Exitech, NA 0.3, Quadrupole, outer sigma: 0.68, inner sigma: 0.36) was used to subject the obtained silicon wafer having the resist film to pattern irradiation such that the average line width of the pattern obtained was 20 nm. The reticle used was a mask with a line size of 20 nm and a line:space ratio of 1:1.
The resist film exposed to light was baked at 90° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38% by mass) for 30 seconds, and rinsed with pure water for 30 second. The resulting resist film was spin-dried to thereby obtain a positive-type pattern.
A composition AL412 (manufactured by Brewer Science) for the formation of an underlayer film was applied to a silicon wafer and baked at 205° C. for 60 seconds to form an underlayer film having a film thickness of 20 nm. A resist composition in one of Examples 40 to 47 and Comparative Example 4 shown in the table was applied to the underlayer film and baked at 100° C. for 60 seconds to form a resist film having a film thickness of 35 nm.
An EUV exposure device (Micro Exposure Tool manufactured by Exitech, NA 0.3, Quadrupole, outer sigma: 0.68, inner sigma: 0.36) was used to subject the obtained silicon wafer having the resist film to pattern irradiation such that the average line width of the pattern obtained was 20 nm. The reticle used was a mask with a line size of 20 nm and a line:space ratio of 1:1.
The resist film exposed to light was baked at 90° C. for 60 seconds, developed with n-butyl acetate for 30 seconds, and spin-dried to thereby obtain a negative-type pattern.
The roughness performance was evaluated using Line Width Roughness (LWR) performance.
The irradiation energy when a 1:1 line-and-space pattern with an average line width of 20 nm was resolved was defined as sensitivity (Eop).
The line width of the line-and-space pattern with a line width of 20 nm (line:space=1:1) resolved at the Eop described above was measured at 250 randomly selected points. Then the standard deviation of the measurements was determined, and 3a (nm) was computed and used as the Line Width Roughness (LWR). The smaller the value of the LWR, the better the performance.
A cross-sectional shape of one of the 1:1 line-and-space patterns with a line width of 20 nm obtained by alkali development was observed under a scanning electron microscope (S-4800 manufactured by Hitachi, Ltd.) to measure the pattern line width La in a top portion (surface portion) of the resist pattern and the pattern line width Lb in a bottom portion of the resist pattern. The value of La/Lb was used as an indicator, and the cross-sectional shape of the line pattern was evaluated according to the following criteria.
A cross-sectional shape of one of the 1:1 line-and-space patterns with a line width of 20 nm obtained by organic solvent development was observed under a scanning electron microscope (S-4800 manufactured by Hitachi, Ltd.) to measure the pattern line width La in a top portion (surface portion) of the resist pattern and the pattern line width Lb in a bottom portion of the resist pattern. The value of La/Lb was used as an indicator, and the cross-sectional shape of the line pattern was evaluated according to the following criteria.
The evaluation results obtained are shown in Tables 3-1 to 3-4.
As can be seen from the results in Tables 3-1 to 3-4, the patterns obtained by the pattern forming method using the resist composition of the invention have good roughness performance, and their pattern shapes have good rectangularity. However, in Comparative Example 1 in which the resin (A) does not include the repeating unit A, Comparative Example 2 in which the resin (A) does not include the repeating unit B, and Comparative Examples 3 and 4 in which the resin (A) does not include the repeating unit C, both the roughness performance and the rectangularity are poorer than those in the Examples. This shows that, to obtain good roughness performance and a good pattern shape with good rectangularity, it is important for the resin (A) to include all the repeating units A, B, and C.
The present invention can provide an actinic ray-sensitive or radiation-sensitive resin composition having good roughness performance and capable of forming a pattern having good rectangularity and also provide an actinic ray-sensitive or radiation-sensitive film using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, and a method for manufacturing an electronic device.
While the invention has been described in detail with reference to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-153660 | Sep 2021 | JP | national |
| 2022-099259 | Jun 2022 | JP | national |
This is a continuation of International Application No. PCT/JP2022/033959 filed on Sep. 9, 2022, and claims priority from Japanese Patent Application No. 2021-153660 filed on Sep. 21, 2021 and Japanese Patent Application No. 2022-099259 filed on Jun. 20, 2022, the entire disclosures of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP22/33959 | Sep 2022 | WO |
| Child | 18611436 | US |
