POLYMER, PHOTORESIST COMPOSITIONS INCLUDING THE SAME, AND PATTERN FORMATION METHODS

Abstract

A polymer including a first repeating unit comprising an acid labile group; an anionic endgroup selected from a carboxylate group or a sulfamate group; and an organic cation.

Description

FIELD

The present invention relates to polymers for photoresist compositions and to pattern formation methods using such photoresist compositions. The invention finds applicability in lithographic applications in the semiconductor manufacturing industry.

BACKGROUND

Photoresist materials are photosensitive compositions typically used for transferring an image to one or more underlying layers such as a metal, semiconductor or dielectric layer disposed on a semiconductor substrate. To increase the integration density of semiconductor devices and allow for the formation of structures having dimensions in the nanometer range, photoresists and photolithography processing tools having high-resolution capabilities have been and continue to be developed.

Chemically amplified photoresists are conventionally used for high-resolution processing. Such resists typically employ a polymer having acid-labile groups, a photoacid generator and an acid quenching material. Pattern-wise exposure to activating radiation through a photomask causes the acid generator to form an acid which, during post-exposure baking, causes cleavage of the acid-labile groups in exposed regions of the polymer. Acid quenching materials are often added to the photoresist composition for controlling the diffusion of the acid to unexposed region to improve the contrast. The result of the lithographic process is the creation of difference in solubility characteristics between exposed and unexposed regions of the resist in a developer solution. In a positive tone development (PTD) process, exposed regions of the photoresist layer become soluble in the developer and are removed from the substrate surface, whereas unexposed regions, which are insoluble in the developer, remain after development to form a positive image. The resulting relief image permits selective processing of the substrate.

Despite the advancement in resist technology, there is still a need for photoresists compositions that address one or more problems associated with the state of the art. In particular, there is a continuing need for photoresist compositions that can achieve a higher sensitivity and/or a lower LWR for line/space patterns.

SUMMARY

An aspect provides a polymer including a first repeating unit comprising an acid labile group; an anionic endgroup selected from a carboxylate group or a sulfamate group; and an organic cation.

Another aspect provides a method of preparing the polymer including polymerizing: a first monomer comprising the acid labile group; and a compound comprising a carboxylate group or a sulfamate group.

Still another aspect provides a photoresist composition including a first polymer comprising the polymer; and a solvent.

Another aspect provides a method of forming a pattern including applying a layer of a photoresist composition on a substrate to form a photoresist composition layer; pattern-wise exposing the photoresist composition layer with activating radiation to form an exposed photoresist composition layer; and developing the exposed photoresist composition layer.

Yet another aspect provides a polymer including a first repeating unit comprising an acid labile group; an anionic endgroup selected from a carboxylate group, a sulfonate group, or a sulfamate group; and an organic cation, wherein the polymer is a polymerization product of a compound represented by at least one of Formulae (9c), (10c), or (10d):

wherein R²² and R²³ are each independently hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_3-30 cycloalkenyl, substituted or unsubstituted C_3-30 heterocycloalkenyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl; provided that at least one of R²² and R²³ is not hydrogen; R²² and R²³ are optionally bonded together to form a ring; R²⁴ and R²⁵ are each independently substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl; R²⁶ to R²⁹ are each independently hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl; X is cyano or halogen; L¹⁵ and L¹⁶ are each independently a divalent linking group; L¹⁷ is a single bond or a divalent linking group; each A⁻ is a carboxylate group, a sulfamate group, or a sulfonate group; and each M⁺ is an organic cation.

The above described and other features are exemplified by the following detailed description.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments. examples of which are illustrated in the present description. In this regard, the present exemplary embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

As used herein, the terms “a,” “an,” and “the” do not denote a limitation of quantity and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and/or” unless clearly indicated otherwise. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The suffix “(s)” is intended to include both the singular and the plural of the term that it modifies, thereby including at least one of that term. “Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not. The terms “first,” “second,” and the like, herein do not denote an order, quantity, or importance, but rather are used to distinguish one element from another. When an element is referred to as being “on” another element, it may be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. It is to be understood that the described components, elements, limitations, and/or features of aspects may be combined in any suitable manner in the various aspects.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, “actinic rays” or “radiation” means, for example, a bright line spectrum of a mercury lamp, far ultraviolet rays represented by an excimer laser, extreme ultraviolet rays (EUV light), X-rays, particle rays such as electron beams and ion beams, or the like. In addition, in the present invention, “light” means actinic rays or radiation. The krypton fluoride laser (KrF laser) is a particular type of excimer laser, which is sometimes referred to as an exciplex laser. “Excimer” is short for “excited dimer,” while “exciplex” is short for “excited complex.” An excimer laser uses a mixture of a noble gas (argon, krypton, or xenon) and a halogen gas (fluorine or chlorine), which under suitable conditions of electrical stimulation and high pressure, emits coherent stimulated radiation (laser light) in the ultraviolet range. Furthermore, “exposure” in the present specification includes, unless otherwise specified, not only exposure by a mercury lamp, far ultraviolet rays represented by an excimer laser, X-rays, extreme ultraviolet rays (EUV light), or the like, but also writing by particle rays such as electron beams and ion beams.

A used herein, an “organic group” includes one or more carbon atoms, for example 1 to 60 carbon atoms. The term “hydrocarbon” refers to an organic compound or to an organic group having at least one carbon atom and at least one hydrogen atom. The term “alkyl” refers to a straight or branched chain saturated hydrocarbon group having the specified number of carbon atoms and having a valence of one; “alkylene” refers to an alkyl group having a valence of two; “hydroxyalkyl” refers to an alkyl group substituted with at least one hydroxyl group (—OH); “alkoxy” refers to “alkyl-O—”; “carboxyl” and “carboxylic acid group” refer to a group having the formula “—C(═O)—OH”; “cycloalkyl” refers to a monovalent group having one or more saturated rings in which all ring members are carbon; “cycloalkylene” refers to a cycloalkyl group having a valence of two; “alkenyl” refers to a straight or branched chain, monovalent hydrocarbon group having at least one carbon-carbon double bond; “alkenoxy” refers to “alkenyl-O—”; “alkenylene” refers to an alkenyl group having a valence of two; “cycloalkenyl” refers to a non-aromatic cyclic divalent hydrocarbon group having at least three carbon atoms, with at least one carbon-carbon double bond; “alkynyl” refers to a monovalent hydrocarbon group having at least one carbon-carbon triple bond; the term “aromatic group” refers to a monocyclic or polycyclic ring system that satisfies the Huckel Rule and includes carbon atoms in the ring, and optionally may include one or more heteroatoms selected from N, O, and S instead of a carbon atom in the ring; “aryl” refers to a monovalent aromatic monocyclic or polycyclic ring system where every ring member is carbon, and may include a group with an aromatic ring fused to at least one cycloalkyl or heterocycloalkyl ring; “arylene” refers to an aryl group having a valence of two; “alkylaryl” refers to an aryl group that has been substituted with an alkyl group; “arylalkyl” refers to an alkyl group that has been substituted with an aryl group; “aryloxy” refers to “aryl-O—”; and “arylthio” refers to “aryl-S-”.

The prefix “hetero” means that the compound or group includes at least one member that is a heteroatom (e.g., 1, 2, 3, or 4 or more heteroatom(s)) instead of a carbon atom, wherein the heteroatom(s) is each independently N, O, S, Si, or P; “heteroatom-containing group” refers to a substituent group that includes at least one heteroatom; “heteroalkyl group” refers to an alkyl group having 1-4 or more heteroatoms instead of carbon; “heterocycloalkyl group” refers to a cycloalkyl group having 1-4 or more heteroatoms as ring members instead of carbon; “heterocycloalkylene group” refers to a heterocycloalkyl group having a valence of two; “heteroaryl group” refers to an aryl group having 1-4 or more heteroatoms as ring members instead of carbon; and “heteroarylene group” refers to an heteroaryl group having a valence of two.

Each of the foregoing substituent groups optionally may be substituted unless expressly provided otherwise. For example, where the group is cited without specifying that it is substituted or unsubstituted, the group includes both a group having no substituent and a group having a substituent. The term “optionally substituted” refers to being substituted or unsubstituted.

“Substituted” means that at least one hydrogen atom of the chemical structure is replaced with another terminal substituent group that is typically monovalent, provided that the designated atom's normal valence is not exceeded. When the substituent is oxo (i.e., ═O), then two geminal hydrogen atoms on the carbon atom are replaced with the terminal oxo group. Combinations of substituents or variables are permissible. Exemplary substituent groups that may be present on a “substituted” position include, but are not limited to, nitro (—NO₂), cyano (—CN), hydroxyl (—OH), oxo (═O), amino (—NH₂), mono- or di-(C_1-6)alkylamino, alkanoyl (such as a C_2-6 alkanoyl group such as acyl), formyl (—C(═O)H), carboxylic acid or an alkali metal or ammonium salt thereof; esters (including acrylates, methacrylates, and lactones) such as C_2-6 alkyl esters (—C(═O)O-alkyl or —OC(═O)-alkyl) and C_7-13 aryl esters (—C(═O)O-aryl or —OC(═O)-aryl), amido (—C(═O)NR₂ wherein R is hydrogen or C_1-6 alkyl), carboxamido (—CH₂C(═O)NR₂ wherein R is hydrogen or C_1-6 alkyl), halogen, thiol (—SH), C_1-6 alkylthio (—S-alkyl), thiocyano (—SCN), C_1-6 alkyl, C_2-6 alkenyl, C_2-6 alkynyl, C_1-6 haloalkyl, C_1-9 alkoxy, C_1-6 haloalkoxy, C_3-12 cycloalkyl, C_5-18 cycloalkenyl, C_2-18 heterocycloalkenyl, C_6-12 aryl having at least one aromatic ring (e.g., phenyl, biphenyl, naphthyl, or the like, each ring either substituted or unsubstituted aromatic), C_7-19 arylalkyl having 1 to 3 separate or fused rings and from 6 to 18 ring carbon atoms, arylalkoxy having 1 to 3 separate or fused rings and from 6 to 18 ring carbon atoms, C_7-12 alkylaryl, C_3-12 heterocycloalkyl, C_3-12 heteroaryl, C_1-6 alkyl sulfonyl (—S(═O)₂-alkyl), C_6-12 arylsulfonyl (—S(═O)₂-aryl), or tosyl (CH₃C₆H₄SO₂—).

The term “halogen” means a monovalent substituent that is fluorine (fluoro), chlorine (chloro), bromine (bromo), or iodine (iodo). The prefix “halo” means a group including one or more of a fluoro, chloro, bromo, or iodo substituent instead of a hydrogen atom. A combination of halo groups (e.g., bromo and fluoro), or only fluoro groups may be present.

As used herein, an “acid-labile group” refers to a group in which a bond is cleaved by the action of an acid, optionally and typically with thermal treatment, resulting in formation of a polar group, such as a carboxylic acid or alcohol group, being formed on the polymer, and optionally and typically with a moiety connected to the cleaved bond becoming disconnected from the polymer. In other systems, a non-polymeric compound may include an acid-labile group that may be cleaved by the action of an acid, resulting in formation of a polar group, such as a carboxylic acid or alcohol group on a cleaved portion of the non-polymeric compound. Such acid is typically a photo-generated acid with bond cleavage occurring during post-exposure baking (PEB); however, embodiments are not limited thereto, and, for example, such acid may be thermally generated. Acid-labile groups are also commonly referred to in the art as “acid-cleavable groups,” “acid-cleavable protecting groups,” “acid-labile protecting groups,” “acid-leaving groups,” “acid-decomposable groups,” and “acid-sensitive groups.”

As used herein, when a definition is not otherwise provided, a “divalent linking group” refers to a divalent group including one or more of —O—, —S—, —Te—, —Se—, —C(O)—, —N(R^b)—, —S(O)—, —S(O)₂—, —C(S)—, —C(Te)—, —C(Se)—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^b is hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_1-20 heteroalkyl, substituted or unsubstituted C_6-30 aryl, or substituted or unsubstituted C_3-30 heteroaryl. Typically, the divalent linking group includes one or more of —O—, —S—, —C(O)—, —N(R^b)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^b is hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. More typically, the divalent linking group includes at least one of —O—, —C(O)—, —C(O)O—, —N(R^b)—, —C(O)N(R^b)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^b is hydrogen, substituted or unsubstituted C_1-10 alkyl, substituted or unsubstituted C_1-10 heteroalkyl, substituted or unsubstituted C_6-10 aryl, or substituted or unsubstituted C_3-10 heteroaryl.

The present disclosure relates to polymers including a quenching group at the terminal end of the polymer backbone. Such quenching groups may be a neutral acid quencher, an ionic acid quencher, or a photodecomposable quencher (PDQ), each of which may be located at a terminal end of the polymer backbone. This allows each polymeric chain of the photoresist polymer to have an acid quencher or a PDQ functionality in close proximity, which may limit self-aggregation and phase segregation of the quencher or the PDQ within the photoresist composition. As a result, the quencher or PDQ functionality may achieve a more homogenous dispersion in the resulting photoresist film to improve lithographic performance.

An aspect provides a polymer that includes a first repeating unit including an acid labile group; and an organic cation. In some aspects, the polymer may include a first repeating unit including an acid labile group, and a second repeating unit including a lactone group, a polar group, or a combination thereof. For example, the polar group may be a hydroxyalkyl group, a hydroxycycloalkyl group, a cyanoalkyl group, a cyanocycloalkyl group, a hydroxyaryl group, a fluoroalcohol group, a sulfonamide group, or the like, or a combination thereof. In some aspects, the first repeating unit may include an acid labile group. In some aspects, the second repeating unit may include a hydroxyaryl group.

Suitable acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, ketal groups, tertiary carbonate groups, and tertiary carbamate groups. Typically, the acid labile group may be an acetal group, a ketal group, a tertiary carbonate group, a tertiary carbamate group, or a tertiary ester group. As used herein, the “tertiary carbamate group” includes tertiary carbamate ester groups having alkyl groups, tertiary carbamate ester groups having aryl groups, and tertiary carbamate ester groups having a combination of alkyl and aryl groups. As used herein, the “tertiary carbonate group” includes tertiary carbonate ester groups having alkyl groups, tertiary carbonate ester groups having aryl groups, and tertiary carbonate ester groups having a combination of alkyl and aryl groups. Preferably, the acid liable group of the second repeating unit includes a tertiary ester group.

The first repeating unit of the polymer may include an acid labile group that is derived from one or more monomers of Formulae (1) to (5):

In Formulae (1) to (3), each R^a is independently hydrogen, fluorine, cyano, substituted or unsubstituted C_1-10 alkyl, or substituted or unsubstituted C_1-10 fluoroalkyl. Preferably, R^a is hydrogen, fluorine, or substituted or unsubstituted C_1-5 alkyl, typically methyl.

In Formula (1), L¹ is a divalent linking group. For example, L¹ may be a divalent linking group including at least one carbon atom, at least one heteroatom, or a combination thereof. For example, L¹ may include 1 to 10 carbon atoms and at least one heteroatom. In one or more embodiments, L¹ may be —OCH₂—, —OCH₂CH₂O— or —N(R^c)—, wherein R^c is hydrogen, substituted or unsubstituted C_1-10 alkyl, substituted or unsubstituted C_1-10 heteroalkyl, substituted or unsubstituted C_6-10 aryl, or substituted or unsubstituted C_3-10 heteroaryl.

In Formulae (1), (2), and (4), R¹ to R³ may each independently be hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_1-20 heterocycloalkyl, substituted or unsubstituted C2-20 alkenyl, substituted or unsubstituted C_3-20 cycloalkenyl, substituted or unsubstituted C_3-20 heterocycloalkenyl, substituted or unsubstituted C_6-20 aryl, or substituted or unsubstituted C_2-20 heteroaryl; provided that only one of R¹ to R³ may be hydrogen, and provided that when one of R¹ to R³ is hydrogen, one or both of the others of R¹ to R³ are substituted or unsubstituted C_6-20 aryl or substituted or unsubstituted C_4-20 heteroaryl. Preferably, R¹ to R³ are each independently substituted or unsubstituted C_1-6 alkyl or substituted or unsubstituted C_3-10 cycloalkyl.

In Formulae (1), (2), and (4), any two of R¹ to R³ together optionally form a ring, and each of R¹ to R³ optionally may include as part of their structure one or more groups chosen from —O—, —C(O)—, —N(R^c)—, —S—, or —S(O)₂—, wherein R^c may be hydrogen, a straight chain or branched C_1-20 alkyl, monocyclic or polycyclic C_3-20 cycloalkyl, or monocyclic or polycyclic C_1-20 heterocycloalkyl. For example, any one or more of R¹ to R³ may be independently a group of the formula —CH₂C(═O)CH_(3−n)Y_n, where each Y is independently substituted or unsubstituted C_1-30 heterocycloalkyl, and n is 1 or 2. For example, each Y may be independently substituted or unsubstituted C_1-30 heterocycloalkyl including a group of the formula —O(C^a1)(C^a2)O—, wherein C^a1 and C^a2 are each independently hydrogen or substituted or unsubstituted C_1-10 alkyl, and where C^a1 and C^a2 together optionally form a ring.

In Formulae (3) and (5), R⁴ and R⁵ may be each independently hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_1-20 heterocycloalkyl, substituted or unsubstituted C_6-20 aryl, or substituted or unsubstituted C_2-20 heteroaryl; and R⁶ may be substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, or substituted or unsubstituted C_1-30 heterocycloalkyl. Optionally, one of R⁴ or R⁵ together with R⁶ may form a heterocyclic ring. Preferably, R⁴ and R⁵ may be each independently hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, or substituted or unsubstituted C_1-20 heterocycloalkyl.

In Formulae (4) and (5), X^a and X^b are each independently a polymerizable group selected from vinyl and norbornyl; and L² and L³ are each independently a single bond or a divalent linking group, provided that L² may not be a single bond when X^a is vinyl and L³ may not be a single bond when X^b is vinyl. Preferably, L² and L³ are each independently substituted or unsubstituted C_6-30 arylene or substituted or unsubstituted C_3-30 cycloalkylene.

In Formulae (4) and (5), each of n1 and n2 may independently be 0 or 1. It is to be understood that when n1 or n2 is 0, the corresponding L2 or L3 group is connected directly to the respective oxygen atom.

Non-limiting examples of monomers for providing a repeating unit including an acid labile group include the following:

wherein R^d is hydrogen, halogen, substituted or unsubstituted C_1-6 alkyl, or substituted or unsubstituted C_3-6 cycloalkyl.

The first repeating unit of the polymer is typically present in an amount from 20 to 100 mole percent (mol %), more typically from 25 to 75 mol %, and still more typically from 30 to 70 mol %, based on total repeating units of the polymer.

As noted above, the polymer may further include a second repeating unit that includes a lactone group, a polar group, or a combination thereof. For example, the polar group may be a hydroxyalkyl group, a hydroxycycloalkyl group, a cyanoalkyl group, a cyanocycloalkyl group, a hydroxyaryl group, a fluoroalcohol group, a sulfonamide group, or the like, or a combination thereof.

In some embodiments, the second repeating unit may include a repeating unit of Formulae (6), (7), or a combination thereof:

In Formulae (6) and (7), each R^a may be hydrogen, fluorine, cyano, or substituted or unsubstituted C_1-10 alkyl. Preferably, R^a may be hydrogen, fluorine, or substituted or unsubstituted C_1-5 alkyl, typically hydrogen or methyl.

In Formulae (6) and (7), L⁴ and L⁵ may each independently be a single bond or one or more divalent linking groups. For example, L⁴ and L⁵ may each independently be —O—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. In some aspects, L⁴ and L⁵ may each independently be a single bond, or one or more groups selected from —C(O)O—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof.

In Formula (6), R⁷ may be substituted or unsubstituted C_1-100 or C_1-20 alkyl, typically C_1-12 alkyl; substituted or unsubstituted C_3-30 or C_3-20 cycloalkyl; substituted or unsubstituted poly(C_1-3 alkylene oxide); or a monocyclic, polycyclic, or fused polycyclic C_4-20 lactone-containing group. The substituted C_1-100 or C_1-20 alkyl, the substituted C_3-30 or C_3-20 cycloalkyl, and the substituted poly(C_1-3 alkylene oxide) may be substituted with one or more of a sulfonamide group (e.g., —NHSO₂CF₃), a hydroxyl group, a cyano group, or a fluoroalcohol group (e.g., —C(CF₃)₂OH).

In Formula (7), Ar¹ may be a substituted C_5-60 aromatic group that optionally includes one or more aromatic ring heteroatoms chosen from N, O, S, or a combination thereof, wherein the aromatic group may be monocyclic, non-fused polycyclic, or fused polycyclic. When the C_5-60 aromatic group is polycyclic, the ring or ring groups may be fused (such as naphthyl or the like), non-fused, or a combination thereof. When the polycyclic C_5-60 aromatic group is non-fused, the ring or ring groups may be directly linked (such as biaryls, biphenyl, or the like) or may be bridged by a heteroatom (such as triphenylamino or diphenylene ether). In some aspects, the polycyclic C_5-60 aromatic group may include a combination of fused rings and directly linked rings (such as binaphthyl or the like).

In Formula (7), y may be an integer from 1 to 12, preferably from 1 to 6, and typically from 1 to 3. Each R^x may independently be hydrogen or methyl, provided that at least one R^x is hydrogen.

Non-limiting examples of such repeating units of the polymer may include:

wherein R^d may be hydrogen, fluorine, cyano, or substituted or unsubstituted C_1-10 alkyl. Preferably, R^d may be hydrogen, fluorine, or substituted or unsubstituted C_1-5 alkyl, typically methyl.

When present, the polymer typically includes the second repeating unit in an amount from 10 to 60 mol %, typically from 10 to 50 mol %, more typically from 10 to 40 mol %, based on total repeating units of the polymer.

In some aspects, the polymer may further optionally include one or more additional repeating units. The additional repeating units may be, for example, one or more additional units for purposes of adjusting properties of the photoresist composition. Exemplary additional units may include those derived from one or more of (meth)acrylate, vinyl aromatic, vinyl ether, vinyl ketone, and/or vinyl ester monomers. The one or more additional repeating units, if present in the polymer, may be used in an amount of up to 90 mol %, typically from 3 to 50 mol %, based on total repeating units of the polymer.

The polymer further includes an anionic end group that is chosen from a carboxylate group or a sulfamate group, and an organic cation. The anionic endgroup is bonded to a backbone or chain terminus of the polymer and may derived from a chain transfer agent or other suitable compound. For example, the anionic endgroup that is derived from the chain transfer agent may be bonded to the backbone of the polymer via an alkylene group, a cycloalkylene group, an arylene group, or a heteroarylene group, each of which may further comprise as part of its structure one or more groups selected from —O—, —C(O)—, —C(O)O—, —S—, —S(O)₂—, —N(R^c)—, or —C(O)N(R^c)— wherein R^c is hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, or substituted or unsubstituted C_3-20 heterocycloalkyl. It is to be understood that, in being bonded to the backbone of the polymer, the endgroup is not a repeating unit of the polymer.

The chain transfer agent may be any compound based on the dithioester or trithiocarbonate functional groups and suitable for chain transfer under conditions of reversible addition-fragmentation transfer (RAFT) polymerization. In one or more embodiments, the polymer may be a polymerization product of a compound of Formula (8):

wherein x is 0 or 1.

In Formula (8), Z is a C_1-30 organic group that may be substituted or unsubstituted. For example, Z may be substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Typically, Z may be substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_3-20 heterocycloalkyl, substituted or unsubstituted C_6-24 aryl, substituted or unsubstituted C_7-25 arylalkyl, substituted or unsubstituted C_7-25 alkylaryl, substituted or unsubstituted C_2-20 heteroaryl, substituted or unsubstituted C_3-20 heteroarylalkyl, or substituted or unsubstituted C_3-20 alkylheteroaryl. Preferably, Z may be substituted or unsubstituted phenyl.

In Formula (8), L₁₀ may be a divalent linking group. Typically, the divalent linking group may include one or more of —O—, —S—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Preferably, the divalent linking group includes at least one of —O—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (8), A⁻ may be a carboxylate group (—C(O)O⁻) or a sulfamate group (—NHS(O)₂O⁻). In other words, A⁻ is an anionic group that is covalently boded to L¹⁰. In Formula (9), M may be an organic cation as defined herein.

In the compound of Formula (8), the group of the formula:

may be included in the polymerization product as an endgroup. This group can be removed by a number of methods including a reaction with a radical source, for example, by radical induced reduction.

In one or more embodiments, the compound may be represented by Formula (8a):

In Formula (8a), each R⁹ independently may be substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Typically, each R⁹ independently may be substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_3-20 heterocycloalkyl, substituted or unsubstituted C_6-24 aryl, substituted or unsubstituted C_7-25 arylalkyl, substituted or unsubstituted C_7-25 alkylaryl, substituted or unsubstituted C_2-20 heteroaryl, substituted or unsubstituted C_3-20 heteroarylalkyl, or substituted or unsubstituted C_3-20 alkylheteroaryl.

In Formula (8a), x may be an integer from 0 to 5. Typically, x may be 0, 1, 2, or 3. Preferably, x may be 0 or 1.

In Formula (8a), L¹⁰, A⁻, and M⁺ are each as defined for Formula (8).

Exemplary compounds of Formulae (8) or (8a) may include one or more of the following:

In one or more embodiments, the polymer may be a polymerization product of compound represented by one of Formulae (9a) or (9b):

In Formulae (9a) and (9b), R¹⁰ to R¹³ may each independently be hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_3-30 cycloalkenyl, substituted or unsubstituted C_3-30 heterocycloalkenyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Typically. R¹⁰ to R¹³ may each independently be hydrogen, halogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_3-20 heterocycloalkyl, substituted or unsubstituted C_6-24 aryl, substituted or unsubstituted C_7-25 arylalkyl, substituted or unsubstituted C_7-25 alkylaryl, substituted or unsubstituted C_2-20 heteroaryl, substituted or unsubstituted C_3-20 heteroarylalkyl, or substituted or unsubstituted C_3-20 alkylheteroaryl.

In Formulae (9a) and (9b), at least one of R¹⁰ and R¹¹ is not hydrogen, and at least one of R¹² and R¹³ is not hydrogen.

In Formulae (9a) and (9b), R¹⁰ and R¹¹ may be optionally bonded together to form a ring, and R¹² and R¹³ may be optionally bonded together to form a ring. Each of R¹⁰ to R¹³ optionally may further include as part of their structure one or more groups chosen from —O—, —C(O)—, —N(R^c)—, —S—, or —S(O)₂—, wherein R^c may be hydrogen, a straight chain or branched C_1-20 alkyl, monocyclic or polycyclic C_3-20 cycloalkyl, or monocyclic or polycyclic C_1-20 heterocycloalkyl.

In Formulae (9a) and (9b), X may be cyano or halogen.

In Formula (9b), L¹¹ may be a divalent linking group. Typically, the divalent linking group may include one or more of —O—, —S—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Preferably, the divalent linking group includes at least one of —O—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (9b), A⁻ is a carboxylate group or a sulfamate group; and M⁺ is an organic cation as defined herein.

Exemplary compounds of Formulae (9a) or (9b) may include the following:

In one or more embodiments, the polymer may be a polymerization product of a compound of Formulae (10a), (10b), or (10c):

In Formula (10a), R¹⁴ and R¹⁹ may be each independently substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Typically, R¹⁴ and R¹⁹ may be each independently substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_3-20 heterocycloalkyl, substituted or unsubstituted C_6-24 aryl, substituted or unsubstituted C_7-25 arylalkyl, substituted or unsubstituted C_7-25 alkylaryl, substituted or unsubstituted C_2-20 heteroaryl, substituted or unsubstituted C_3-20 heteroarylalkyl, or substituted or unsubstituted C_3-20 alkylheteroaryl.

In Formula (10a), R¹⁴ optionally may further include as part of its structure one or more groups chosen from —O—, —C(O)—, —N(R^c)—, —S—, or —S(O)₂—, wherein R^c may be hydrogen, a straight chain or branched C_1-20 alkyl, monocyclic or polycyclic C_3-20 cycloalkyl, or monocyclic or polycyclic C_1-20 heterocycloalkyl.

In Formulae (10a), L¹² may be a divalent linking group. Typically, the divalent linking group may include one or more of —O—, —S—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Preferably, the divalent linking group includes at least one of —O—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (10b), R¹⁵ to R¹⁸ may each independently be hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Typically. R¹⁵ to R¹⁸ may each independently be hydrogen, substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_3-20 heterocycloalkyl, substituted or unsubstituted C_6-24 aryl, substituted or unsubstituted C_7-25 arylalkyl, substituted or unsubstituted C_7-25 alkylaryl, substituted or unsubstituted C_2-20 heteroaryl, substituted or unsubstituted C_3-20 heteroarylalkyl, or substituted or unsubstituted C_3-20 alkylheteroaryl.

In Formulae (10b), L¹³ may be a single bond or a divalent linking group. Typically, the divalent linking group may include one or more of —O—, —S—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl. Preferably, the divalent linking group includes at least one of —O—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, substituted or unsubstituted C_1-10 alkylene, substituted or unsubstituted C_3-10 cycloalkylene—, substituted or unsubstituted C_3-10 heterocycloalkylene, substituted or unsubstituted C_6-10 arylene, substituted or unsubstituted C_3-10 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (10c), L¹⁴ may be a divalent linking group. Typically, the divalent linking group may include one or more of —O—, —S—, —C(O)—, —C(O)O—, —N(R^c)—, —C(O)N(R^c)—, —S(O)—, —S(O)₂—, substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_3-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, substituted or unsubstituted C_3-30 heteroarylene, or a combination thereof, wherein R^c may be hydrogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_1-30 heteroalkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_1-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_2-30 alkynyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (10c), R²⁰ and R²¹ may be each independently substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formulae (10a), (10b), and (10c), A⁻ is a carboxylate group or a sulfamate group; and M⁺ is an organic cation as defined herein.

Exemplary compounds of Formulae (10a), (10b), or (10c) may include the following:

In still other embodiments, the polymer may be a polymerization product of a compound of at least one of Formulae (9c), (10c), or (10d):

In Formula (9c), R²² and R²³ may each independently be hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_2-30 alkenyl, substituted or unsubstituted C_3-30 cycloalkenyl, substituted or unsubstituted C_3-30 heterocycloalkenyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl, provided that at least one of R²² and R²³ is not hydrogen.

In Formula (9c), R²² and R²³ are optionally bonded together to form a ring. Each of R²² and R²³ optionally may further include as part of their structure one or more groups chosen from —O—, —C(O)—, —N(R^c)—, —S—, or —S(O)₂—, wherein R^c may be hydrogen, a straight chain or branched C_1-20 alkyl, monocyclic or polycyclic C_3-20 cycloalkyl, or monocyclic or polycyclic C_1-20 heterocycloalkyl.

In Formula (9c), X may be cyano or halogen.

In Formula (9c) and (10c), L¹⁵ and L¹⁶ may each independently be a divalent linking group.

In Formula (10c), R²⁴ and R²⁵ may be each independently substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (10d), R²⁶ to R²⁹ may each independently be hydrogen, halogen, substituted or unsubstituted C_1-30 alkyl, substituted or unsubstituted C_3-30 cycloalkyl, substituted or unsubstituted C_3-30 heterocycloalkyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_7-30 arylalkyl, substituted or unsubstituted C_7-30 alkylaryl, substituted or unsubstituted C_2-30 heteroaryl, substituted or unsubstituted C_3-30 heteroarylalkyl, or substituted or unsubstituted C_3-30 alkylheteroaryl.

In Formula (10d), L¹⁷ may be a single bond or a divalent linking group.

In Formulae (9c), (10c), and (10d), A⁻ is a carboxylate group or a sulfamate group; and M⁺ is an organic cation as defined herein.

The organic cation may be any suitable organic cation. For example, the organic cation may be a sulfonium cation or an iodonium cation. For example, the photoactive cation may be a sulfonium cation of Formula (11) or an iodonium cation of Formula (12):

In Formulae (11) and (12), R³⁰ to R³⁴ may each independently be substituted or unsubstituted C_1-20 alkyl, substituted or unsubstituted C_3-20 cycloalkyl, substituted or unsubstituted C_2-20 alkenyl, substituted or unsubstituted C_6-30 aryl, substituted or unsubstituted C_6-30 iodoaryl, substituted or unsubstituted C_3-30 heteroaryl, substituted or unsubstituted C_7-20 arylalkyl, or substituted or unsubstituted C_4-20 heteroarylalkyl, or combinations thereof. Each of R³⁰ to R³² may be either separate or connected to another group of R³⁰ to R³² via a single bond or a divalent linking group to form a ring. R³³ and R³⁴ may be either separate or connected to each other via a single bond or a divalent linking group to form a ring. Each of R³⁰ to R³⁴ optionally may include as part of its structure a divalent linking group. Each of R³⁰ to R³⁴ independently may optionally comprise an acid-labile group chosen, for example, from tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups.

Exemplary sulfonium cations of Formula (11) may include one or more of the following:

Exemplary iodonium cations of Formula (12) may include one or more of the following:

Non-limiting exemplary polymers of the present invention may include the following:

wherein a, b, and c, each represent the mol % of the repeating unit based on 100 mol % of total repeating units in the polymer, and M⁺ is an organic cation as defined herein.

The polymer typically has a weight average molecular weight (M_w) from 1,000 to 50,000 Dalton (Da), preferably from 2,000 to 30,000 Da, more preferably 2,500 to 20,000 Da, and still more preferably from 3,500 to 15,000 Da. The PDI of the polymer is typically from 1.1 to 3, and more typically from 1.1 to 2. Molecular weights are determined by gel permeation chromatography (GPC) using polystyrene standards.

The polymer may be prepared using any suitable method(s) in the art. For example, one or more monomers corresponding to the repeating units described herein may be combined, or fed separately, using suitable solvent(s) and initiator, and polymerized in a reactor. For example, the polymer may be obtained by polymerization of the respective monomers under any suitable conditions, such as by heating at an effective temperature, irradiation with actinic radiation at an effective wavelength, or a combination thereof.

For example, the polymer may be prepared by radically or thermally initiated polymerization of the monomers, preferably in a degassed solvent, in the presence of the chain transfer agent or other reactive compound, using the aforementioned reversible addition-fragmentation transfer (RAFT) process. The polymerization may be carried out in batch mode, by batch addition of monomers and/or initiator to the reaction mixture containing the chain transfer addition, by metered addition of separate feeds of one or more of the monomers and/or initiator and/or chain transfer agent to the reaction mixture, or any other suitable method for combining the reactants. It will be appreciated that block copolymers may be produced by sequential addition of monomers for each block to the reaction mixture, or a polymer having a graded composition (statistical or gradient) may be formed by gradually changing the monomer proportions and/or composition in the feed over time. All such polymers preparable by the RAFT method are contemplated herein.

The polymer may be prepared using an initiator. Suitable initiators may include any radical initiator useful in the art, such as peroxy initiators, diazo initiators, or the like. For example, peroxy initiators such as tert-butyl hydroperoxide, tert-butyl peroxy 2-ethyl hexanoate (tert-butyl peroctoate), t-butyl peroxy pivalate, tert-butyl peroxy benzoate, di-benzoyl peroxide, tert-butyl peroxy isobutyrate, diazo initiators such as azo-bis-isobutyronitrile (AIBN), 4,4′-azobis(4-cyanovaleric acid); or the like. Preferred initiators include those sold under the trade name VAZO by DuPont, such as VAZO 52, VAZO 67, VAZO 88, and VAZO V-601 free-radical initiators. Alternatively, the polymerization may be carried out by thermal initiation (e.g., greater than about 120° C. more preferably greater than about 150° C.).

Other methods of synthesizing suitable polymers are also contemplated, and with proper choice and control of initiators, solvent, monomers, and polymerization process and isolation conditions could yield polymers of desirable molecular weight and dispersity. Alternative polymerization methods include, but are not limited to free radical polymerization, atom transfer radical polymerization (ATRP), stable free radical polymerization (SFRP), nitroxide mediated polymerization (NMP), reversible-deactivation radical polymerization, anionic step growth polymerization, cationic step growth polymerization, and ring opening metathesis polymerization (ROMP).

The polymer as synthesized could optionally further include a removal or modification process of the living chain end by further treatment with other chemistry. One exemplary method is to treat molecularly dissolved copolymer chains with excess free radical initiators, amines or oxidants for RAFT chain end removal, or hetero Diels-Alder reaction, or reaction with nucleophiles, as summarized by Willcock et. al in “End group removal and modifications of RAFT polymers” in Polym. Chem., 2010, 1, 149-157. The other polymer chain end removal or modification examples could be practiced as described in Harth et. al in “Chain End Functionalization in Nitroxide-Mediated “Living” Free Radical Polymerizations” Macromolecules 2001, 34, 3856-3862, or Coessens et. al in “Dehalogenation of polymers prepared by atom transfer radical polymerization” in Macromol. Rapid Commun. 1999, 20, 66.

Also provided is a photoresist composition including the polymer as described herein and a solvent. For example, the photoresist composition may include a first polymer that is a polymer as described herein, and may further include a second (different) polymer that is structurally different from the first polymer.

The second polymer may include one or more repeating units as described herein, for example, such as those derived from one or more of (meth)acrylate, vinyl aromatic, vinyl ether, vinyl ketone, and/or vinyl ester monomers. For example, the second polymer may include a repeating unit that includes an acid labile group, a hydroxyaryl group, a fluoroalcohol group, a sulfonamide group, a lactone group, or a combination thereof.

The second polymer typically has a M_w from 1,000 to 50,000 Da, specifically from 2,000 to 30,000 Da, more specifically from 3,000 to 20,000 Da, still more specifically from 3,000 to 10,000 Da. The PDI of the polymer, which is the ratio of M_w to M_n is typically from 1.1 to 3, and specifically from 1.1 to 2. Molecular weights are determined by GPC using polystyrene standards.

The second polymer may be prepared using any suitable methods in the art. For example, one or more monomers corresponding to the repeating units described herein may be combined, or fed separately, using suitable solvent(s) and initiator, and polymerized in a reactor. For example, the second polymer may be obtained by polymerization of the respective monomers under any suitable conditions, such as by heating at an effective temperature, irradiation with actinic radiation at an effective wavelength, or a combination thereof.

The photoresist composition includes a solvent for dissolving the components of the composition and facilitating its coating on a substrate. Preferably, the solvent is an organic solvent conventionally used in the manufacture of electronic devices. Suitable solvents include, for example: aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane and 1-chlorohexane; alcohols such as methanol, ethanol, 1-propanol, iso-propanol, tert-butanol, 2-methyl-2-butanol and 4-methyl-2- pentanol; propylene glycol monomethyl ether (PGME), ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane and anisole; ketones such as acetone, methyl ethyl ketone, methyl iso-butyl ketone, 2-heptanone and cyclohexanone (CHO); esters such as ethyl acetate, n-butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), hydroxyisobutyrate methyl ester (HBM) and ethyl acetoacetate; lactones such as gamma-butyrolactone (GBL) and epsilon-caprolactone; lactams such as N-methyl pyrrolidone; nitriles such as acetonitrile and propionitrile; cyclic or non-cyclic carbonate esters such as propylene carbonate, dimethyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and propylene carbonate; polar aprotic solvents such as dimethyl sulfoxide and dimethyl formamide; water; and combinations thereof. Of these, preferred solvents are PGME, PGMEA, EL, GBL, HBM, CHO, and combinations thereof. The total solvent content (i.e., cumulative solvent content for all solvents) in the photoresist composition is typically from 40 to 99 wt %. more typically from 70 to 99 wt %, and still more typically from 85 to 99 wt %, based on total weight of the photoresist composition. The desired solvent content will depend, for example, on the desired thickness of the coated photoresist layer and coating conditions.

In the photoresist compositions, the polymer is typically present in the photoresist composition in an amount from 10 to 99.9 wt %, typically from 25 to 99 wt %, and more typically from 50 to 95 wt %, based on total solids of the photoresist composition. It will be understood that total solids includes the polymer, PAGs, and other non-solvent components.

The photoresist composition may further include a photoacid generator (PAG). The PAG may be in ionic or non-ionic form. The PAG may be in polymeric or non-polymeric form. In polymeric form, the PAG may be present as a moiety in a repeating unit of a polymer that is derived from a polymerizable PAG monomer.

Non-ionic sulfonates and sulfonyl compounds may function as photoacid generators. Exemplary non-ionic PAGs include nitrobenzyl derivatives, for example, 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonic acid esters, for example, 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives, for example, bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane; glyoxime derivatives, for example, bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonic acid ester derivatives of an N-hydroxyimide compound, for example, N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester; and halogen-containing triazine compounds, for example, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine. Suitable non-polymerized photoacid generators are further described in U.S. Pat. No. 8,431,325 to Hashimoto et al. in column 37, lines 11-47 and columns 41-91. Other suitable non-ionic PAGS include sulfonated esters and sulfonyloxy ketones, nitrobenzyl esters, s-triazine derivatives, benzoin tosylate, t-butylphenyl α-(p-toluenesulfonyloxy)-acetate, and t-butyl α-(p-toluenesulfonyloxy)-acetate; as described in U.S. Pat. Nos. 4,189,323 and 8,431,325.

Suitable ionic PAG compounds maybe of the formula G⁺A⁻, wherein G⁺ is a photoactive cation and A⁻ is an anion that can generate a photoacid. The photoactive cation is preferably chosen from onium cations, preferably iodonium or sulfonium cations. Particularly suitable anions include those whose conjugated acids have a pKa of from −15 to 10. The anion is typically an organic anion having a sulfonate group or a non-sulfonate-type group, such as sulfonamidate, sulfonimidate, methide, or borate.

In some embodiments, the photoactive cation may be a sulfonium cation or an iodonium cation, such as those described herein for Formulae (11) and/or (12).

Exemplary organic anions having a sulfonate group include one or more of the following:

Exemplary non-sulfonated anions include one or more of the following:

Commonly used onium salts may include, for example, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate; di-t-butyphenyliodonium perfluorobutanesulfonate, and di-t-butyphenyliodonium camphorsulfonate. Other useful PAG compounds are known in the art of chemically amplified photoresists and include, for example: non-ionic sulfonyl compounds, for example, 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonic acid esters, for example, 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives, for example, bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane; glyoxime derivatives, for example, bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonic acid ester derivatives of an N-hydroxyimide compound, for example, N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester; and halogen-containing triazine compounds, for example, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine. Suitable photoacid generators are further described in U.S. Pat. Nos. 8,431,325 and 4,189,323.

In some aspect, the firs polymer or the second polymer optionally may further comprise a repeating unit comprising a PAG moiety, for example a repeating unit derived from one or more monomers of Formula (14):

In Formula (14), R^m may be hydrogen, fluorine, cyano, or substituted or unsubstituted C_1-10 alkyl. Preferably, R^m is hydrogen, fluorine, or substituted or unsubstituted C_1-5 alkyl, typically methyl. Q¹ may be a single bond or a divalent linking group. Preferably, Q¹ may include 1 to 10 carbon atoms and at least one heteroatom, more preferably —C(O)—O—.

In Formula (14), Q² may be one or more of substituted or unsubstituted C_1-30 alkylene, substituted or unsubstituted C_3-30 cycloalkylene, substituted or unsubstituted C_2-30 heterocycloalkylene, substituted or unsubstituted C_6-30 arylene, or substituted or unsubstituted C_3-30 heteroarylene. Preferably, Q² may be a divalent C_1-30 perfluoroalkylene group that is optionally substituted.

In Formula (14), Z⁻ is an anionic moiety, the conjugated acid of which typically has a pKa from −15 to 1. Z⁻ may be a sulfonate, a carboxylate, an anion of a sulfonamide, an anion of a sulfonimide, or a methide anion. Particularly preferred anion moieties are fluorinated alkyl sulfonates and fluorinated sulfonimides.

In Formula (14), G⁺ is an organic cation as defined above. In some embodiments, G⁺ is an iodonium cation substituted with two alkyl groups, two aryl groups, or a combination of alkyl and aryl groups; or a sulfonium cation substituted with three alkyl groups, three aryl groups, or a combination of alkyl and aryl groups.

Exemplary monomers of Formula (14) may include one or more of the following:

wherein G⁺ is the organic cation.

The first polymer and/or the second polymer may include a repeating unit comprising a PAG moiety in an amount from 1 to 12 mol %, typically from 1 to 8 mol %, more typically from 2 to 6 mol %, based on total repeating units in the polymer.

Typically, when the photoresist composition includes a non-polymeric PAG, the PAG may be present in the photoresist composition in an amount of from 0.1 to 65 wt %, more typically 1 to 30 wt %, based on total solids of the photoresist composition.

In some aspects, the anion and/or cation of the PAG does not include and is free of —F, —CF₃, or —CF₂— groups. It should be understood that “free of —F, —CF₃, or —CF₂— groups” means that the anion and/or cation of the PAG excludes groups such as —CH₂CF₃ and —CH₂CF₂CH₃. In still other aspects, the anion and/or the cation of the PAG is free of fluorine (i.e., does not contain a fluorine atom and is not substituted by a fluorine-containing group). In some aspects, the photoacid generator is free of fluorine (i.e., both the photoactive cation and the anion are free of fluorine).

In some aspects, the photoresist composition may further include a material that comprises one or more base-labile groups (a “base-labile material”). As referred to herein, base-labile groups are functional groups that can undergo cleavage reaction to provide polar groups such as hydroxyl, carboxylic acid, sulfonic acid, and the like, in the presence of an aqueous alkaline developer after exposure and post-exposure baking steps. The base-labile group will not react significantly (e.g., will not undergo a bond-breaking reaction) prior to a development step of the photoresist composition that comprises the base-labile group. Thus, for instance, a base-labile group will be substantially inert during pre-exposure soft-bake, exposure, and post-exposure bake steps. By “substantially inert” it is meant that ≤5%, typically ≤1%, of the base-labile groups (or moieties) will decompose, cleave, or react during the pre-exposure soft-bake, exposure, and post-exposure bake steps. The base-labile group is reactive under typical photoresist development conditions using, for example, an aqueous alkaline photoresist developer such as a 0.26 normal (N) aqueous solution of tetramethylammonium hydroxide (TMAH). For example, a 0.26 N aqueous solution of TMAH may be used for single puddle development or dynamic development, e.g., where the 0.26 N TMAH developer is dispensed onto an imaged photoresist layer for a suitable time such as 10 to 120 seconds(s). An exemplary base-labile group is an ester group, typically a fluorinated ester group. Preferably, the base-labile material is substantially not miscible with and has a lower surface energy than the polymer and other solid components of the photoresist composition. When coated on a substrate, the base-labile material can thereby segregate from other solid components of the photoresist composition to a top surface of the formed photoresist layer.

In some aspects, the base-labile material may be a polymeric material, also referred to herein as a base-labile polymer, which may include one or more repeating units comprising one or more base-labile groups. For example, the base-labile polymer may comprise a repeating unit comprising two or more base-labile groups that are the same or different. A preferred base-labile polymer includes at least one repeating unit comprising two or more base-labile groups, for example a repeating unit comprising two or three base-labile groups.

The base-labile polymer may be prepared using any suitable methods in the art. For example, the base-labile polymer may be obtained by polymerization of the respective monomers under any suitable conditions, such as by heating at an effective temperature, irradiation with actinic radiation at an effective wavelength, or a combination thereof. Additionally, or alternatively, one or more base-labile groups may be grafted onto the backbone of a polymer using suitable methods.

In some aspects, the base-labile material is a single molecule comprising one more base-labile ester groups, preferably one or more fluorinated ester groups. The base-labile materials that are single molecules typically have a molecular weight in the range from 50 to 1,500 Da.

When present, the base-labile material is typically present in the photoresist compositions in an amount of from 0.01 to 10 wt %, typically from 1 to 5 wt %, based on total solids of the photoresist composition.

Additionally, or alternatively, to the base-labile polymer, the photoresist compositions may further include one or more polymers in addition to and different from the polymer as described above. For example, the photoresist compositions may include an additional polymer or polymer as described above but different in composition. Additionally, or alternatively, the one or more additional polymers may include those well known in the photoresist art, for example, those chosen from polyacrylates, polyvinylethers, polyesters, polynorbornenes, polyacetals, polyethylene glycols, polyamides, polyacrylamides, polyphenols, novolacs, styrenic polymers, polyvinyl alcohols, or combinations thereof.

The photoresist composition may further include one or more additional, optional additives. For example, optional additives may include actinic and contrast dyes, anti-striation agents, plasticizers, speed enhancers, sensitizers, photo-decomposable quenchers (PDQ) (and, also known as photo-decomposable bases), basic quenchers, thermal acid generators, surfactants, and the like, or combinations thereof. If present, the optional additives are typically present in the photoresist compositions in an amount of from 0.01 to 10 wt %, based on total solids of the photoresist composition.

PDQs generate a weak acid upon irradiation. The acid generated from a photo-decomposable quencher is not strong enough to react rapidly with acid-labile groups that are present in the resist matrix. Exemplary photo-decomposable quenchers include, for example, photo-decomposable cations, and preferably those also useful for preparing strong acid generator compounds, paired with an anion of a weak acid (pKa>1) such as, for example, an anion of a C_1-20 carboxylic acid or C_1-20 sulfonic acid. Exemplary carboxylic acids include formic acid, acetic acid, propionic acid, tartaric acid, succinic acid, cyclohexanecarboxylic acid, benzoic acid, salicylic acid, and the like. Exemplary sulfonic acids include p-toluene sulfonic acid, camphor sulfonic acid and the like. In a preferred embodiment, the photo-decomposable quencher is a photo-decomposable organic zwitterion compound such as diphenyliodonium-2-carboxylate.

The PDQ may be in non-polymeric or polymer-bound form. The polymerized units containing the photo-decomposable quencher are typically present in an amount from 0.1 to 30 mol %, preferably from 1 to 10 mol % and more preferably from 1 to 2 mol %, based on total repeating units of the polymer.

Exemplary basic quenchers include, for example, linear aliphatic amines such as tributylamine, trioctylamine, triisopropanolamine, tetrakis(2-hydroxypropyl)ethylenediamine:n-tert-butyldiethanolamine, tris(2-acetoxy-ethyl) amine, 2,2′,2″,2′″-(ethane-1,2-diylbis(azanetriyl)) tetraethanol, 2-(dibutylamino)ethanol, and 2,2′,2″-nitrilotriethanol; cyclic aliphatic amines such as 1-(tert-butoxycarbonyl)- 4-hydroxypiperidine, tert-butyl 1-pyrrolidinecarboxylate, tert-butyl 2-ethyl-1H-imidazole-1-carboxylate, di-tert-butyl piperazine-1,4-dicarboxylate, and N-(2-acetoxy-ethyl)morpholine; aromatic amines such as pyridine, di-tert-butyl pyridine, and pyridinium; linear and cyclic amides and derivatives thereof such as N,N-bis(2-hydroxyethyl)pivalamide, N,N-diethylacetamide, N¹,N¹,N³,N³- tetrabutylmalonamide, 1-methylazepan-2-one, 1-allylazepan-2-one, and tert-butyl 1,3-dihydroxy-2-(hydroxymethyl)propan-2-ylcarbamate; ammonium salts such as quaternary ammonium salts of sulfonates, sulfamates, carboxylates, and phosphonates; imines such as primary and secondary aldimines and ketimines; diazines such as optionally substituted pyrazine, piperazine, and phenazine; diazoles such as optionally substituted pyrazole, thiadiazole, and imidazole; and optionally substituted pyrrolidones such as 2-pyrrolidone and cyclohexyl pyrrolidine.

The basic quenchers may be in non-polymeric or polymer-bound form. When in polymeric form, the quencher may be present in repeating units of the polymer. The repeating units containing the quencher are typically present in an amount of from 0.1 to 30 mol %, preferably from 1 to 10 mol % and more preferably from 1 to 2 mol %, based on total repeating units of the polymer.

Exemplary surfactants include fluorinated and non-fluorinated surfactants and can be ionic or non-ionic, with non-ionic surfactants being preferable. Exemplary fluorinated non-ionic surfactants include perfluoro C₄ surfactants such as FC-4430 and FC-4432 surfactants, available from 3M Corporation; and fluorodiols such as POLYFOX PF-636, PF-6320, PF-656, and PF-6520 fluorosurfactants from Omnova. In an aspect, the photoresist composition further includes a surfactant polymer including a fluorine-containing repeating unit.

Also provided are methods of forming a pattern. According to an aspect, a method of forming a pattern includes applying a layer of a photoresist composition on a substrate to form a photoresist composition layer; pattern-wise exposing the photoresist composition layer with activating radiation to form an exposed photoresist composition layer; and developing the exposed photoresist composition layer. The photoresist composition includes the polymer as described herein and a solvent.

Patterning methods using the photoresist compositions of the invention will now be described. Suitable substrates on which the photoresist compositions can be coated include electronic device substrates. A wide variety of electronic device substrates may be used in the present invention, such as: semiconductor wafers; polycrystalline silicon substrates; packaging substrates such as multichip modules; flat panel display substrates; substrates for light emitting diodes (LEDs) including organic light emitting diodes (OLEDs); and the like, with semiconductor wafers being typical. Such substrates are typically composed of one or more of silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon germanium, gallium arsenide, aluminum, sapphire, tungsten, titanium, titanium-tungsten, nickel, copper, and gold. Suitable substrates may be in the form of wafers such as those used in the manufacture of integrated circuits, optical sensors, flat panel displays, integrated optical circuits, and LEDs. Such substrates may be any suitable size. Typical wafer substrate diameters are 200 to 300 millimeters (mm), although wafers having smaller and larger diameters may be suitably employed according to the present invention. The substrates may include one or more layers or structures which may optionally include active or operable portions of devices being formed.

Typically, one or more lithographic layers such as a hardmask layer, for example, a spin-on-carbon (SOC), amorphous carbon, or metal hardmask layer, a CVD layer such as a silicon nitride (SiN), a silicon oxide (SiO), or silicon oxynitride (SiON) layer, an organic or inorganic underlayer, or combinations thereof, are provided on an upper surface of the substrate prior to coating a photoresist composition of the present invention. Such layers, together with an overcoated photoresist layer, form a lithographic material stack.

Optionally, a layer of an adhesion promoter may be applied to the substrate surface prior to coating the photoresist compositions. If an adhesion promoter is desired, any suitable adhesion promoter for polymer films may be used, such as silanes, typically organosilanes such as trimethoxyvinylsilane, triethoxyvinylsilane, hexamethyldisilazane, or an aminosilane coupler such as gamma-aminopropyltriethoxysilane. Particularly suitable adhesion promoters include those sold under the AP™ 3000, AP™ 8000, and AP™ 9000S designations, available from DuPont Electronics & Industrial (Marlborough, Massachusetts).

The photoresist composition may be coated on the substrate by any suitable method, including spin coating, spray coating, dip coating, doctor blading, or the like. For example, applying the layer of photoresist may be accomplished by spin coating the photoresist in solvent using a coating track, in which the photoresist is dispensed on a spinning wafer. During dispensing, the wafer is typically spun at a speed of up to 4,000 rotations per minute (rpm), for example, from 200 to 3,000 rpm, for example, from 1,000 to 2,500 rpm, for a period from 15 to 120 seconds to obtain a layer of the photoresist composition on the substrate. It will be appreciated by those skilled in the art that the thickness of the coated layer may be adjusted by changing the spin speed and/or the total solids of the composition. A photoresist composition layer formed from the compositions of the invention typically has a dried layer thickness from 3 to 30 micrometers (μm), preferably from greater than 5 to 30 μm, and more preferably from 6 to 25 μm.

The photoresist composition is typically next soft-baked to minimize the solvent content in the layer, thereby forming a tack-free coating and improving adhesion of the layer to the substrate. The soft bake is performed, for example, on a hotplate or in an oven, with a hotplate being typical. The soft bake temperature and time will depend, for example, on the photoresist composition and thickness. The soft bake temperature is typically from 80 to 170° C., and more typically from 90 to 150° C. The soft bake time is typically from 10 seconds to 20 minutes (mins.), more typically from 1 to 10 mins., and still more typically from 1 to 2 mins. The heating time can be readily determined by one of ordinary skill in the art based on the components of the composition.

The photoresist layer is next pattern-wise exposed to activating radiation to create a difference in solubility between exposed and unexposed regions. Reference herein to exposing a photoresist composition to radiation that is activating for the composition indicates that the radiation can form a latent image in the photoresist composition. The exposure is typically conducted through a patterned photomask that has optically transparent and optically opaque regions corresponding to regions of the resist layer to be exposed and unexposed, respectively. Such exposure may, alternatively, be conducted without a photomask in a direct writing method, typically used for e-beam lithography. The activating radiation typically has a wavelength of sub-400 nm, sub-300 nm or sub-200 nm, with 248 nm (KrF), 193 nm (ArF dry or immersion), 13.5 nm (EUV) wavelengths or e-beam lithography being preferred. Preferably, the activating radiation is 248 nm radiation. The methods find use in immersion or dry (non-immersion) lithography techniques. The exposure energy is typically from 1 to 200 millijoules per square centimeter (mJ/cm²), preferably from 10 to 100 mJ/cm² and more preferably from 20 to 50 mJ/cm², dependent upon the exposure tool and components of the photoresist composition.

Following exposure of the photoresist layer, a post-exposure bake (PEB) of the exposed photoresist layer is performed. The PEB can be conducted, for example, on a hotplate or in an oven, with a hotplate being typical. Conditions for the PEB will depend, for example, on the photoresist composition and layer thickness. The PEB is typically conducted at a temperature from 70 to 150° C., preferably from 75 to 120° C., and a time from 30 to 120 seconds. A latent image defined by the polarity-switched (exposed regions) and unswitched regions (unexposed regions) is formed in the photoresist.

The exposed photoresist layer is then developed with a suitable developer to selectively remove those regions of the layer that are soluble in the developer while the remaining insoluble regions form the resulting photoresist pattern relief image. In the case of a positive-tone development (PTD) process, the exposed regions of the photoresist layer are removed during development and unexposed regions remain. Conversely, in a negative-tone development (NTD) process, the exposed regions of the photoresist layer remain, and unexposed regions are removed during development. Application of the developer may be accomplished by any suitable method such as described above with respect to application of the photoresist composition, with spin coating being typical. The development time is for a period effective to remove the soluble regions of the photoresist, with a time of from 5 to 60 seconds being typical. Development is typically conducted at room temperature.

Suitable developers for a PTD process include aqueous base developers, for example, quaternary ammonium hydroxide solutions such as TMAH, preferably 0.26 N TMAH, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and the like. Suitable developers for an NTD process are organic solvent-based, meaning the cumulative content of organic solvents in the developer is 50 wt % or more, typically 95 wt % or more, 98 wt % or more, or 100 wt %, based on total weight of the developer. Suitable organic solvents for the NTD developer include, for example, those chosen from ketones, esters, ethers, hydrocarbons, and mixtures thereof. The developer is typically 2-heptanone or n-butyl acetate.

A coated substrate may be formed from the photoresist compositions of the invention. Such a coated substrate includes: (a) a substrate having one or more layers to be patterned on a surface thereof; and (b) a layer of the photoresist composition over the one or more layers to be patterned.

The photoresist pattern may be used, for example, as an etch mask, thereby allowing the pattern to be transferred to one or more sequentially underlying layers by known etching techniques, typically by dry-etching such as reactive ion etching. The photoresist pattern may, for example, be used for pattern transfer to an underlying hardmask layer which, in turn, is used as an etch mask for pattern transfer to one or more layers below the hardmask layer. If the photoresist pattern is not consumed during pattern transfer, it may be removed from the substrate by known techniques, for example, oxygen plasma ashing. The photoresist compositions may, when used in one or more such patterning processes, be used to fabricate semiconductor devices such as memory devices, processor chips (CPUs), graphics chips, optoelectronic chips, LEDs, OLEDs, as well as other electronic devices.

The invention is further illustrated by the following non-limiting examples.

EXAMPLES

Synthesis Examples

The synthetic reactions were performed under an anhydrous nitrogen atmosphere. All chemicals were used as received from commercial suppliers and without further purification. Proton nuclear magnetic resonance (¹H-NMR) spectra for all compounds were obtained on a 500-megahertz (MHz) NMR spectrometer. Carbon-13 nuclear magnetic resonance (¹³C-NMR) spectra were obtained at 126 MHz. The chemical shifts for ¹H-NMR are reported in δ parts per million, ppm) relative to an internal deuterated acetone residual signal. Multiplicities are indicated by singlet (s), doublet (d), triplet (t), multiplet (m), doublet of doublets (dd), doublet of triplets (dt), triplet of triplets (tt), or broad singlet (br).

Synthesis of Modified RAFT Reagents

Synthesis of Compound 1

Triphenyl sulfonium bromide (TPS-Br) (300 milligrams (mg), 0.9 millimoles (mmol)) and 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPCTTPA) (250 mg, 0.9 mmol) were added to a mixture of dichloromethane and deionized (DI) water. NaHCO₃ (75 mg; 0.9 mmol) was then added and the reaction mixture was stirred for 20 minutes at room temperature. The organic layer was separated and then washed multiple times with DI water to remove the residual NaHCO₃. The organic layer was separated again and then dried over anhydrous sodium sulfate. The product was then filtered and used for the next reaction step without further purification. ¹H-NMR (δ, chloroform-d) 7.99-7.49 ppm (m, 20H), 2.55-2.45 ppm (m, 4H), and 1.95 ppm (s, 3H).

Synthesis of Compound 2

4-methyl substituted triphenyl sulfonium bromide (TTS-Br) (800 mg; 2.08 mmol,) and CPCTTPA (922 mg, 2.28 mmol) were added to a mixture of dichloromethane and deionized (DI) water. NaHCO₃ (192 mg, 2.28 mmol) was then added, and the reaction mixture was stirred for 20 minutes at room temperature. The organic layer was separated and then washed multiple times with DI water to remove the residual NaHCO₃. The organic layer was separated again and then dried over anhydrous sodium sulfate. The product was then filtered and used for the next reaction step without further purification. ¹H-NMR (δ, acetone-d₆) 7.91-7.90 ppm (m, 2H), 7.66-7.64 ppm (d, 7H), 7.59-7.57 ppm (d, 6H), 7.52-7.48 ppm (m, 2H), 2.43 ppm (s, 9H), 2.30 ppm (m, 4H), and 1.90 ppm (s, 3H). ¹³C-NMR (δ, acetone-d₆) 174.04 ppm, 173.48 ppm, 145.74 ppm, 144.84 ppm, 133.28 ppm, 132.08 ppm, 131.26 ppm, 128.87 ppm, 126.62 ppm, 122.38 ppm, 118.84 ppm, 34.35 ppm, 23.20 ppm, and 20.79 ppm.

Synthesis of Compound 3

TTS-Br (580 mg; 1.51 mmol,) and 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid (CDSPA) (668 mg, 1.66 mmol) were added to a mixture of dichloromethane and DI water. NaHCO₃ (253 mg, 1.66 mmol) was then added and the reaction mixture was stirred for 20 minutes at room temperature. The organic layer was separated and then washed multiple times with DI water to remove the residual NaHCO₃. The organic layer was separated again and then dried over anhydrous sodium sulfate. The product was then filtered and used for the next reaction step without further purification. ¹H-NMR (δ, acetone-d₆) 7.86-7.84 ppm (d, 6H), 7.66- 7.64 ppm (d, 6H), 3.42 ppm (t, 2H), 2.51 ppm (s, 9H), 2.46-2.34 ppm (m, 4H), 1.90 ppm (s, 3H), 1.73 ppm (m, 2H), 1.45-1.31 ppm (m, 18H), 0.89 ppm (m, 3H). ¹³C NMR (δ, acetone-d₆) 173.36 ppm, 145.81 ppm, 132.01 ppm, 131.20 ppm, 122.32 ppm, 119.39 ppm, 47.58 ppm, 36.49 ppm, 35.51 ppm, 31.75 ppm, 23.92 ppm, 22.45 ppm, 20.62 ppm, and 13.48 ppm.

Synthesis of Compound 4

A first solution of CPCTTPA (2.0 g, 8.0 mmol) and 20 mL tetrahydrofuran (THF) was a prepared, and then a second solution of LiOH (0.2 g) in 5 mL water was prepared separately. The first and second solutions were then combined, and the resulting mixture was stirred at room temperature for 1 hour. The solvent was then removed under a reduced pressure to produce a lithium 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid salt. To the lithium salt was added DI water (20 mL), dichloromethane (20 mL), and bis(4-(tert-butyl)phenyl)iodonium acetate (3.66.0 g, 8.0 mmol), and the reaction mixture was stirred at room temperature for 4 hours. The organic phase was then washed with DI water (5×15 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under a reduced pressure to produce the crude photoactive compound as a white solid. The crude product was suspended in 25 mL of heptane, and the product was isolated by filtration and dried to provide a white solid. Yield: 4.2 g (81.8%). ¹H NMR (δ, acetone-d₆): 8.12-8.00 ppm (m, 6H,), 7.65-5.50 ppm (m, 7H, ArH), 2.55-2.45 ppm (m, 4H), 1.95 ppm (s, 3H), and 1.20 ppm (s, 18H).

Polymer Synthesis

The following monomers were used to prepare the polymers.

Synthesis of Polymer P1

A two-neck round bottom flask was charged with monomer M1 (3.096 g), monomer M3 (5.000 g), and monomer M4 (1.888 g) in an anhydrous mixture of THF and acetonitrile (MeCN), and then 2,2′-azobis(2,4-dimethylvaleronitrile) (0.055 g, 0.24 mmol) was added thereto (obtained from Wako Pure Chemical Industries, Ltd.). A separate solution of Compound 3 (0.752 g, 1.06 mmol) was prepared in 2 mL of THF/MeCN, and this solution was then added to the two-neck round bottom flask. The reaction mixture was then purged with nitrogen for 30 minutes with stirring. The reaction mixture was then heated at 66° C. with stirring for 19 hours. The reaction mixture was then allowed to cool to room temperature and diluted by the addition of anhydrous THF (10 mL), and the resulting solution was added dropwise into methanol (500 mL) to produce a light brown solid. The solid was collected by filtration and dried in a vacuum oven to give Polymer P1 as a light brown solid. Yield: 82%. M_w: 12.6 kDa, PDI: 1.39, as determined by gel permeation chromatography (GPC) using polystyrene standards. The molar ratio of the repeating units M1/M3/M4 was determined by ¹³C-NMR to be 29:55:16.

Synthesis of Polymer P2

A two-neck round bottom flask was charged with monomer M1 (2.51 g), monomer M3 (1.55 g), and monomer M4 (1.95 g) in an anhydrous mixture of THF and acetonitrile (MeCN), and then 2,2′-azobis(2,4-dimethylvaleronitrile) (0.06 g, 0.24 mmol) was added thereto (obtained from Wako Pure Chemical Industries, Ltd.). A separate solution of Compound 3 (0.62 g, 1.06 mmol) was prepared in 2 mL of THF/MeCN, and this solution was then added to the two-neck round bottom flask. The reaction mixture was then purged with nitrogen for 30 minutes with stirring. The reaction mixture was then heated at 66° C. with stirring for 6 hours. The reaction mixture was then allowed to cool to room temperature and diluted by the addition of anhydrous THF (10 mL), and the resulting solution was added dropwise into methanol (200 mL) to produce a pink solid. The solid was collected by filtration and dried in a vacuum oven to give Polymer P2 as a pink solid. Yield: 83%. M_w: 7.0 kDa, PDI: 1.20, as determined by GPC using polystyrene standards. The molar ratio of the repeating units M1/M3/M4 was determined by ¹³C-NMR to be 28:56:16.

Synthesis of Polymer P3

A one-neck 50 mL round bottom flask was charged with monomer M2 (2.08 g, 10.20 mmol), monomer M3 (3.00 g, 10.20 mmol), monomer M5 (0.61 g, 2.27 mmol), THF (3.0 g), and propylene glycol methyl ether acetate (PGMEA) (12.0 g). The contents were stirred for 15 minutes and then dimethyl 2,2′-azobis(2-methylpropionate) (obtained as V-601 from Wako Pure Chemical Industries, Ltd.) (0.052 g, 0.23 mmol) and Compound 4 (0.76 g, 1.13 mmol) were charged to the reaction mixture. The contents of the round bottom flask were then purged under nitrogen for 30 min with stirring. The reaction mixture was then heated at 65° C. with stirring for 20 hours. The reaction mixture was then allowed to cool to room temperature and then a precipitate was formed by the addition of methanol (150 mL). The solid was collected by filtration and dried in a vacuum oven to give Polymer P3 as a light-yellow solid. M_w: 9.0 kDa, PDI: 1.36, as determined by GPC using polystyrene standards. The molar ratio of the repeating units M2/M3/M5 was determined by ¹³C-NMR to be 33/59/8.

Synthesis of Comparative Polymer PC1

A one-neck 100 mL round bottom flask was charged with monomer M1 (5.42 g), monomer M3 (9.28 g), monomer M4 (3.30 g), and PGMEA (30 wt % solution). The contents were stirred for 15 minutes and then dimethyl 2,2′-azobis(2-methylpropionate) (obtained as V-601 from Wako Pure Chemical Industries, Ltd.) (1.09 g, 4.67 mmol) was charged to the reaction mixture. The contents of the round bottom flask were then purged under nitrogen for 30 min with stirring. The reaction mixture was then heated at 80° C. with stirring for 5 hours. The reaction mixture was then allowed to cool to room temperature then a precipitate was formed by the addition of methanol (500 mL). The solid was collected by filtration and dried in a vacuum oven to give Polymer PC1 as a white solid. Yield: 81%. M_w: 7.1 kDa, PDI: 1.66, as determined by GPC using polystyrene standards. The molar ratio of the repeating units M1/M3/M4 was determined by ¹³C-NMR to be 28:56:16.

Synthesis of Comparative Polymer PC2

A 100 mL round bottom flask was charged with monomer M1 (3.09 g), monomer M3 (5.00 g), and monomer M4 (1.88 g), 2,2′-azobis(2,4-dimethylvaleronitrile) (0.06 g, 0.24 mmol) (obtained from Wako Pure Chemical Industries, Ltd.) and 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid (CDSPA) (0.43 g, 1.06 mmol) (obtained from STREM Chemicals). PGMEA (20.9 g) was added thereto. The reaction mixture was then purged with nitrogen for 30 minutes with stirring. The reaction mixture was then heated at 80° C. with stirring for 18 hours. The reaction mixture was then allowed to cool to room temperature and diluted by the addition of anhydrous PMGEA (15 mL), and the resulting solution was added dropwise into methanol (500 mL) to produce a white solid. The solid was collected by filtration and dried in a vacuum oven to give Polymer PC2 as a white solid. Yield: 67%. M_w: 8.4 kDa, PDI: 1.23, as determined by GPC using polystyrene standards. The molar ratio of the repeating units M1/M3/M4 was determined by ¹³C-NMR to be 28:56:16.

Synthesis of Comparative Polymer PC3

A feed solution was made by combining monomer M2 (13.83 g, 68 mmol), monomer M3 (21.60 g, 127 mmol), and monomer M5 (4.57 g, 17 mmol) with PGMEA (36 g). An initiator solution was separately prepared by dissolving 3.42 g of the azo initiator V-65 in 11.7 g of PGMEA/THF (1:1 by wt %) mixture. The polymerization was performed in a 3-neck round bottom flask fitted with a water condenser and a thermometer to monitor the reaction in the flask. The reactor was charged with 21.0 g of PGMEA and heated to 75° C. The feed solution and the initiator solution were each fed into the reactor using syringe pumps over 4 hours. The contents were then stirred for an additional 2 hours. The contents were subsequently cooled to room temperature, diluted with 10 g of THF, and precipitated into 1 L of a 7:3 (v/v) mixture of heptane and isopropanol. The resulting polymer was isolated by filtration. The polymer was dried overnight at 35° C. under vacuum to give a white solid polymer PC3 (about 20 g) with Mw: 6.7 kDa, PDI=2.39, as determined by GPC using polystyrene standards. The molar ratio of the repeating units M2/M3/M5 was determined by ¹³C-NMR to be 32/60/8.

Lithographic Evaluation

Formulation Information

Photoresist compositions were prepared by combining the solid components with solvents using the materials and amounts indicated in Tables 1, where the amounts are expressed in wt % based on 100 wt % of total weight of the solids. The total solids content for the photoresist compositions was 3 wt %. The solvent system contained PGMEA (30 wt %, based on 100 wt % of the total solvent system) and methyl-2-hydroxyisobutyrate (70 wt %, based on 100 wt % of the total solvent system). Each mixture was shaken using a mechanical shaker and then filtered through a PTFE disk-shaped filter having a pore size of 0.2 micron.

Immersion Lithography

Immersion lithography was carried out with a TEL Lithius 300 mm wafer track and ASML 1900i immersion scanner at 1.35 NA, 0.90/0.988 inner/outer sigma, and dipole illumination with 35Y polarization. Wafers for photolithographic testing were coated to a thickness of 800 Å using AR™ 40A bottom antireflective coating (BARC, DuPont Electronics & Industrial) and cured at 205° C./60 seconds. Over the BARC layer was coated a layer having a thickness of 400 Å using AR™ 104 BARC (DuPont Electronics & Industrial) and cured of 175° C./60 seconds, to form a BARC stack. Over the BARC stack was coated as layer having a thickness of 900 Å of a photoresist composition noted in Table 1 using a soft bake at 90° C./60 seconds. Wafers were exposed to a pattern of 38 nm/76 nm pitch lines/spaces at increasing focus and increasing dose and then post-exposure baked (PEB) at 95° C./60 seconds. Following PEB, wafers were developed in 0.26 N aqueous TMAH developer for 12 seconds, rinsed with DI water, and spun dry. Metrology was performed on a Hitachi CG4000 CD-SEM to evaluate Linewidth Roughness (LWR) and sizing energy (E_s), and results thereof are provided in Table 1.

TABLE 1
Example				Additive	Es	LWR
No.	Polymer	PAG	Base	polymer	(mJ/cm2)	(nm)
PR-1	P1	PAG-A	—	S	16.6	3.1
	(87.19)	(9.81)		(3)
PR-2	P2	PAG-A	—	S	21.4	2.9
	(87.19)	(9.81)		(3)
PR-3*	PC1	PAG-A	Q-1	S	13.6	3.31
	(85.98)	(9.81)	(1.21)	(3)
PR-4*	PC2	PAG-A	—	S	X	X
	(87.19)	(9.81)		(3)
*denotes a comparative photoresist composition
X: not resolved

The structures of PAG-A and Q-1 are shown below:

The additive polymer (S) was prepared as described in U.S. Pat. No. 11,480,878 B2, and has the general structure shown below:

As can be seen in Table 1, the photoresist compositions PR-1 and PR-2 achieved improved LWR compared to comparative compositions PR-3 to PR-4.

Contrast Curve Measurements

Formulation Information

Photoresist compositions were prepared by combining the solid components with solvents where the amounts are expressed in wt % based on 100 wt % of total weight of the solids. The total solids content for the photoresist compositions was 1.66 wt %. The solvent system contained PGMEA (50 wt %, based on 100 wt % of the total solvent system) and methyl-2-hydroxyisobutyrate (50 wt %, based on 100 wt % of the total solvent system). Each mixture was shaken using a mechanical shaker and then filtered through a PTFE disk-shaped filter having a pore size of 0.2 micron.

Lithographic Evaluation

The photoresists were each spin-coated on 200 nm silicon wafers with a respective photoresist composition in Table 2 on a TEL Clean Track ACT 8 wafer track, while the silicon wafers were pre-overcoated with a dual BARC stack (60 nm thickness AR™ 3 antireflectant over 80 nm thickness AR™ 40A antireflectant (DuPont Electronics & Imaging). The photoresist compositions in Table 2 were softbaked at 110° C./60 seconds to provide a photoresist layer with a target thickness of about 40 nm. The resist layer thickness was measured with a THERMA-WAVE OP7350. The wafers were exposed with 248 nm radiation on a Canon FPA-5000 ES4 scanner at exposure doses between 3 and 53 mJ/cm² with an increment of 0.5 mJ. The wafers were post-exposure baked at 100° C./60 seconds, developed with MF™-CD26 TMAH developer (DuPont Electronics & Imaging) for 60 seconds, rinsed with DI water, and dried. Photoresist layer thickness measurements were made in exposed regions of the layer. A contrast curve for each wafer was generated. Dose-to-clear (E₀) was determined from the contrast curve as the exposure dose at which the remaining photoresist layer thickness was less than 10% of the original coated thickness. The results are shown in Table 2.

	TABLE 2
	Example		Additive	Additive	E0
	No.	Polymer	1	2	(mJ/cm2)
	PR-5*	PC3	PAG-B	Q-2	34.2
		(77.38)	(19.35)	(3.27)
	PR-6*	PC3	PAG-B	Compound 4	27.7
		(74.75)	(18.69)	(6.56)
	PR-7	PC3	PAG-B	P3	7.3
		(41.13)	(10.28)	(48.59)
	PR-8	—	PAG-B	P3	3.0
			(17.46)	(82.54)
	PR-9	PC3	PAG-B	P3	16.6
		(35.05)	(5.26)	(59.69)
	PR-10	—	PAG-B	P3	9.3
			(8.10)	(91.90)
	*denotes a comparative photoresist composition

The structures of PAG-B and Q-2 are shown below:

As can be seen in Table 2, the photoresist compositions PR-7 to PR-10 achieved improved sensitivity as evident by the smaller E_o in comparison to comparative examples PR-5 and PR-6.

While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A polymer, comprising: a first repeating unit comprising an acid labile group;an anionic endgroup selected from a carboxylate group or a sulfamate group; andan organic cation.

2. The polymer of claim 1, wherein the polymer further comprises a second repeating unit, and wherein the second repeating unit comprises a lactone group, a polar group, or a combination thereof.

3. The polymer of claim 1, wherein the anionic endgroup is bonded to a backbone of the polymer via an alkylene group, a cycloalkylene group, an arylene group, or a heteroarylene group, each of which may further comprise as part of its structure one or more groups selected from —O—, —C(O)—, —C(O)O—, —S—, —S(O)2—, —N(Rc)—, or —C(O)N(Rc)— wherein Rc is hydrogen, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C3-20 cycloalkyl, or substituted or unsubstituted C3-20 heterocycloalkyl.

4. The polymer of claim 1, wherein the polymer is a polymerization product of a compound of Formula (8):

5. The polymer of any one of claim 1, wherein the polymer is a polymerization product of a compound of Formulae (9a) or (9b):

6. The polymer of claim 1, wherein the polymer is a polymerization product of a compound of Formulae (10a), (10b), or (10c):

7. A method of preparing the polymer of claim 1, the method comprising: polymerizing:a first monomer comprising the acid labile group; anda compound comprising a carboxylate group or a sulfamate group.

8. A photoresist composition, comprising: a first polymer comprising the polymer of claim 1; anda solvent.

9. The photoresist composition of claim 8, further comprising a second polymer, wherein the first polymer and the second polymer are different.

10. The photoresist composition of claim 8, further comprising a photoacid generator.

11. A method of forming a pattern, the method comprising: applying a layer of a photoresist composition of claim 8 on a substrate to form a photoresist composition layer;pattern-wise exposing the photoresist composition layer with activating radiation to form an exposed photoresist composition layer; anddeveloping the exposed photoresist composition layer.

12. A polymer, comprising: a first repeating unit comprising an acid labile group;an anionic endgroup selected from a carboxylate group, a sulfonate group, or a sulfamate group; andan organic cation,wherein the polymer is a polymerization product of a compound represented by at least one of Formulae (9c), (10c), or (10d):

13. The polymer of claim 12, wherein the polymer further comprises a second repeating unit, and wherein the second repeating unit comprises a lactone group, a polar group, or a combination thereof.

14. The polymer of claim 12, wherein the anionic endgroup is bonded to a backbone of the polymer via an alkylene group, a cycloalkylene group, an arylene group, or a heteroarylene group, each of which may further comprise as part of its structure one or more groups selected from —O—, —C(O)—, —C(O)O—, —S—, —S(O)2—, —N(Rc)—, or —C(O)N(Rc)— wherein Rc is hydrogen, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C3-20 cycloalkyl, or substituted or unsubstituted C3-20 heterocycloalkyl.

15. A photoresist composition, comprising: a first polymer comprising the polymer of claim 12; anda solvent.

16. The photoresist composition of claim 15, further comprising a second polymer, wherein the first polymer and the second polymer are different.

17. The photoresist composition of claim 15, further comprising a photoacid generator.

18. A method of forming a pattern, the method comprising: applying a layer of a photoresist composition of claim 15 on a substrate to form a photoresist composition layer;pattern-wise exposing the photoresist composition layer with activating radiation to form an exposed photoresist composition layer; anddeveloping the exposed photoresist composition layer.