Resist composition, method for forming resist pattern, copolymer, and compound

Abstract

The present invention employs a resist composition which contains a copolymer that has a constituent unit represented by general formula (a00), a constituent unit represented by general formula (a01), and a constituent unit represented by general formula (a02).　In the formulae, R0a, R0b, R01, and R02 are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. L00 and L01 are each independently a divalent linking group or a single bond. L02 is a divalent linking group. RAr is an aromatic group which may have a specific substituent. RX is an acid dissociable group. Z- is an anion group. Mm+ is an m-valent onium cation. m is an integer of 1 or more. According to this resist composition, high sensitivity is achieved during the formation of a resist pattern, and the effects of roughness reduction and film loss suppression are both enhanced.

Description

Resist composition, method for forming a resist pattern, copolymer and compound

[0001] This application claims priority from Japanese Patent Application No. 2024-032995, filed on March 5, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, advances in lithography technology have led to rapid progress in miniaturization of patterns in the manufacture of semiconductor devices and liquid crystal display devices. A common method for miniaturization is to shorten the wavelength (increase the energy) of exposure light sources. Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions. To satisfy these requirements, chemically amplified resist compositions containing a base component whose solubility in a developer changes with the action of acid and an acid generator component that generates acid upon exposure have been used.

[0003] In chemically amplified resist compositions, a resin having a plurality of structural units is generally used as the base component in order to improve lithography properties, etc. A wide variety of acid generators have been proposed so far. For example, onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, disulfone-based acid generators, etc. are known.

[0004] Furthermore, in chemically amplified resist compositions, polymeric compounds have been proposed that incorporate, as acid generator components, structural units containing acid generating groups that generate acid upon exposure (see, for example, Patent Document 1). Such polymeric compounds function both as acid generators and as base components.

[0005] JP 2014-197168 A

[0006] As lithography technology advances and resist patterns become increasingly finer, for example, in lithography using EUV (extreme ultraviolet) or EB (electron beam), the goal is to form fine patterns of several tens of nanometers. As pattern dimensions become smaller, both high sensitivity to the exposure light source and lithography properties such as reduced roughness are required. In addition, as resist patterns become finer, excessive dissolution of the resist film, particularly the unexposed portions, in the developer during development can cause development loss (film loss). However, conventional resist compositions such as those described in Patent Document 1 require further improvement in terms of these required properties.

[0007] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a resist composition that enables high sensitivity in resist pattern formation, and is effective in both reducing roughness and suppressing film loss; a method of forming a resist pattern that uses this resist composition; a copolymer that is useful for this resist composition; and a compound that can be used to synthesize this copolymer.

[0008] In order to solve the above problems, the present invention employs the following configuration: That is, a first aspect of the present invention is a resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component whose solubility in a developer changes due to the action of the acid, the resin component including a copolymer having a structural unit represented by the following general formula (a00), a structural unit represented by the following general formula (a01), and a structural unit represented by the following general formula (a02) that generates acid upon exposure:

[0009] [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒis an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group. ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ is a divalent linking group. － is an anionic group. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0010] A second aspect of the present invention is a method of forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition related to the first aspect, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

[0011] A third aspect of the present invention is a copolymer having a structural unit represented by the following general formula (a00), a structural unit represented by the following general formula (a01), and a structural unit represented by the following general formula (a02) that generates acid upon exposure:

[0012] [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒ is an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. ０１is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group. ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ is a divalent linking group. － is an anionic group. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0013] A fourth aspect of the present invention is a compound represented by the following general formula (a00-M1) or (a00-M2).

[0014] [In formula (a00-M1) and formula (a00-M2), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. ０ｃ is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group, and p is an integer of 1 to 4.

[0015] According to the present invention, it is possible to provide a resist composition that enables high sensitivity in resist pattern formation, and is effective in both reducing roughness and suppressing film loss; a method of forming a resist pattern that uses this resist composition; a copolymer useful for this resist composition; and a compound that can be used in synthesizing this copolymer.

[0016] In this specification and claims, "aliphatic" is a relative concept to aromatic, and is defined as meaning a group, compound, etc. that does not have aromaticity. "Alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups, unless otherwise specified. The same applies to alkyl groups in alkoxy groups. "Alkylene group" includes linear, branched, and cyclic divalent saturated hydrocarbon groups, unless otherwise specified. "Halogen atom" includes fluorine, chlorine, bromine, and iodine atoms. "Structural unit" means a monomer unit that constitutes a polymer compound (resin, polymer, copolymer). When describing "may have a substituent," it refers to cases where a hydrogen atom (-H) is replaced with a monovalent group, and cases where a methylene group (-CH ２ The term "exposure" encompasses both cases where the radical (-) is substituted with a divalent group.

[0017] An "acid-decomposable group" is a group having acid decomposability in which at least a part of the bond in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases by the action of an acid include groups that decompose by the action of an acid to generate a polar group. Examples of polar groups include a carboxy group, a hydroxyl group, an amino group, and a sulfo group (-SO ３ More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, groups in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0018] The term "acid-dissociable group" refers to either (i) a group having acid dissociability in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a portion of the bond is cleaved by the action of an acid, followed by a decarboxylation reaction, in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Thus, when the acid-dissociable group is dissociated by the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, thereby increasing the polarity. As a result, the polarity of the entire component (A1) increases. The increase in polarity relatively changes the solubility in the developer, increasing the solubility when the developer is an alkaline developer and decreasing the solubility when the developer is an organic developer.

[0019] A "base component" is an organic compound that has film-forming ability. Organic compounds used as base components are broadly classified into non-polymers and polymers. As non-polymers, those with a molecular weight of 500 or more and less than 4000 are usually used (hereinafter referred to as "low molecular weight compounds"). Hereinafter, when referring to "resin," "high molecular weight compound," or "polymer," it refers to a polymer with a molecular weight of 1000 or more. The molecular weight of the polymer is the weight average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography).

[0020] The term "derived structural unit" refers to a structural unit formed by cleavage of a multiple bond between carbon atoms, for example, an ethylenic double bond. In the "acrylic acid ester", the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R αｘ ) is an atom or group other than a hydrogen atom. αｘ ) is substituted with a substituent containing an ester bond, or αｘThis also includes α-hydroxyacrylic esters in which the α-position carbon atom of an acrylic ester is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-position carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, acrylic esters in which the hydrogen atom bonded to the α-position carbon atom has been replaced with a substituent may be referred to as α-substituted acrylic esters.

[0021] The term "derivative" is used as a concept including compounds in which the hydrogen atom at the α-position of the target compound is substituted with other substituents such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of the hydroxyl group of a target compound in which the hydrogen atom at the α-position may be substituted with a substituent is substituted with an organic group; compounds in which a substituent other than a hydroxyl group is bonded to a target compound in which the hydrogen atom at the α-position may be substituted with a substituent; and the like. Unless otherwise specified, the α-position refers to the first carbon atom adjacent to the functional group. Examples of substituents that substitute the hydrogen atom at the α-position of hydroxystyrene include R αｘ Examples include alkyl groups, halogenated alkyl groups, and the like.

[0022] In this specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms, and may exist as enantiomers or diastereoisomers. In such cases, a single chemical formula represents all of the isomers. These isomers may be used alone or as a mixture.

[0023] (Resist Composition) One embodiment of the resist composition generates acid upon exposure, and its solubility in a developer changes due to the action of the acid. The resist composition of this embodiment contains a base component (A) (hereafter also referred to as "component (A)") whose solubility in a developer changes due to the action of an acid. In this resist composition, the component (A) contains a resin component (hereafter this resin component is also referred to as "component (A1)") whose solubility in a developer changes due to the action of an acid. The component (A1) contains a copolymer (hereafter this copolymer is also referred to as "component (A1-0)") that has a structural unit represented by general formula (a00), a structural unit represented by general formula (a01), and a structural unit represented by general formula (a02) that generates acid upon exposure, as described below.

[0024] When a resist film is formed using the resist composition of this embodiment and then subjected to selective exposure, an acid is generated from at least the component (A1-0) in the exposed areas of the resist film, and the solubility of the component (A1) in a developer changes due to the action of the acid, whereas the solubility of the component (A1) in a developer does not change in the unexposed areas of the resist film, resulting in a difference in solubility in a developer between the exposed and unexposed areas of the resist film. Therefore, when the resist film is developed, if the resist composition is positive, the exposed areas of the resist film are dissolved and removed, forming a positive resist pattern, whereas if the resist composition is negative, the unexposed areas of the resist film are dissolved and removed, forming a negative resist pattern.

[0025] The resist composition of this embodiment may be a positive resist composition or a negative resist composition. Furthermore, the resist composition of this embodiment may be for use in an alkaline development process in which an alkaline developer is used for the development treatment during resist pattern formation, or for use in a solvent development process in which a developer containing an organic solvent (organic developer) is used for the development treatment.

[0026] <Base Component (A)> In the resist composition of this embodiment, the component (A) includes a resin component (component (A1)) whose solubility in a developer changes under the action of acid. By using the component (A1), good development contrast can be obtained not only in an alkaline development process but also in a solvent development process. As the component (A), at least one other polymeric compound or low molecular weight compound may be used in combination with the component (A1). In the resist composition of this embodiment, one type of component (A) may be used alone, or two or more types may be used in combination.

[0027] Regarding resin component (A1): The component (A1) contains a copolymer (component (A1-0)) having a structural unit represented by general formula (a00) (hereinafter also referred to as "structural unit (a00)"), a structural unit represented by general formula (a01) (hereinafter also referred to as "structural unit (a01)"), and a structural unit represented by general formula (a02) that generates acid upon exposure (hereinafter also referred to as "structural unit (a02)"). The component (A1-0) may be a copolymer that contains other structural units as needed, in addition to the structural unit (a00), the structural unit (a01), and the structural unit (a02).

[0028] <<Structural Unit (a00)>> The structural unit (a00) is a structural unit represented by the following general formula (a00): This structural unit (a00) has a maleimide structure and functions as a proton source.

[0029] [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒ is an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group.

[0030] In the formula (a00), R ０ａ and R ０ｂare each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０ａ and R ０ｂ In the formula (I), the alkyl group having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. As the halogen atom in the halogenated alkyl group, a fluorine atom is particularly preferred. R ０ａ and R ０ｂ are each preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability, and even more preferably a hydrogen atom, and R ０ａ and R ０ｂ It is particularly preferred that all of these are hydrogen atoms.

[0031] In the formula (a00), L ００ is a divalent linking group or a single bond. ００ Examples of the divalent linking group in the formula (I) include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and a combination thereof.

[0032] ・L ００ A divalent hydrocarbon group which may have a substituent in the formula: L ００ The divalent hydrocarbon group in the formula (I) may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0033] ...L ００The aliphatic hydrocarbon group in the above formula (1) means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in its structure.

[0034] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0035] L ００ When L is a chain hydrocarbon group, some or all of the hydrogen atoms of the chain hydrocarbon group may be substituted with a monovalent group containing a hetero atom. Examples of the monovalent group include a halogen atom, a nitro group, an amino group, a hydroxy group, a carboxy group, a nitrile group, and a thiol group. ００ is a chain hydrocarbon group, a methylene group of the chain hydrocarbon group may be substituted with a divalent group containing a heteroatom. Examples of the divalent group include a carbonyl group, an ether bond [—O—], an ester bond [—C(═O)—O—, —O—C(═O)—], an amide group [—C(═O)—NH—, —HN—C(═O)—], and [—NH—].

[0036] The linear or branched aliphatic hydrocarbon group may or may not have a substituent. The substituent may be a substituent that replaces a hydrogen atom bonded to the linear aliphatic hydrocarbon group, or a substituent that replaces a methylene group (—CH ２ -) may be substituted.

[0037] Examples of groups that substitute hydrogen atoms bonded to the chain-like aliphatic hydrocarbon group include alkoxy groups, halogen atoms, halogenated alkyl groups, hydroxy groups, nitro groups, amino groups, carboxy groups, nitrile groups, and thiol groups. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, or tert-butoxy group, and even more preferably a methoxy group or ethoxy group. Examples of halogen atoms as the substituent include a fluorine atom, chlorine atom, bromine atom, and iodine atom. Examples of halogenated alkyl groups as the substituent include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with the halogen atoms.

[0038] The methylene group (-CH ２ Examples of groups substituting -) include a carbonyl group, an ether bond [-O-], an ester bond [-C(=O)-O-, -O-C(=O)-], an amide group [-C(=O)-NH-, -HN-C(=O)-], and an imino group [-NH-].

[0039] ... Aliphatic hydrocarbon groups containing a ring in their structure Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group here include the same as those described above as "straight-chain or branched-chain aliphatic hydrocarbon groups."

[0040] The cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring: an alicyclic hydrocarbon group) preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0041] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxy group, and a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include the substituents exemplified above as "substituting a hydrogen atom bonded to the chain-like aliphatic hydrocarbon group." In the cyclic aliphatic hydrocarbon group, the methylene group constituting the ring structure may be substituted with a divalent group containing a heteroatom. Examples of the divalent group include a carbonyl group, an ether bond [—O—], an ester bond [—C(═O)—O—], —S—, and —S(═O) ２ -, -S(=O) ２ Examples include —O—, an amide group [—C(═O)—NH—], and an imino group [—NH—].

[0042] ...L ００The aromatic hydrocarbon group in the above formula (1) is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings.

[0043] L ００ Specific examples of the aromatic hydrocarbon group in the formula (I) include a group (arylene group or heteroarylene group) in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle; a group in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of a group (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., a group in which another hydrogen atom has been removed from the aryl group of an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0044] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxy group. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include the substituents exemplified above as "substituents that substitute a hydrogen atom bonded to a cyclic aliphatic hydrocarbon group."

[0045] ・L ００ Preferred examples of the divalent linking group containing a hetero atom include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, and -S(=O) ２ -, -S(=O) ２ -O-, general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ -or-Y ２１ -S(=O) ２ -O-Y ２２ -, wherein Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 1 to 3.

[0046] When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, an acyl group, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

[0047] General formula-Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ -or-Y ２１ -S(=O) ２ -O-Y ２２ -Middle, Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the above-mentioned L ００ Examples of the divalent linking group include the same groups as those (divalent hydrocarbon groups which may have a substituent) mentioned in the description of the divalent linking group in Y ２１ As Y, a linear aliphatic hydrocarbon group is preferred, a linear alkylene group is more preferred, a linear alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or an ethylene group is particularly preferred. ２２ is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group, or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

[0048] Formula - [Y ２１ -C(=O)-O] ｍ” -Y ２２In the group represented by -, m" is an integer of 1 to 3, preferably 1 or 2, and more preferably 1. That is, the group represented by the formula -[Y ２１ -C(=O)-O] ｍ” -Y ２２ The group represented by - includes the group represented by the formula -Y ２１ -C(=O)-O-Y ２２ Among them, groups represented by the formula -(CH ２ ) ａ’ -C(=O)-O-(CH ２ ) ｂ’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0049] Among the above, L ００ is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. ００ is preferably a single bond.

[0050] In the formula (a00), R Ａｒ R is an aromatic group which may have a substituent. Ａｒ The aromatic group in may be monocyclic or polycyclic. The aromatic ring contained in the aromatic group preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 10 carbon atoms.

[0051] Specific examples of the aromatic ring contained in the aromatic group include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a portion of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples of heteroatoms in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Specific examples of the aromatic group are preferably groups in which two hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, more preferably groups in which two hydrogen atoms have been removed from benzene or naphthalene (i.e., a phenylene group or a naphthylene group), and even more preferably groups in which two hydrogen atoms have been removed from benzene (i.e., a phenylene group).

[0052] However, R Ａｒ The substituent that the aromatic group may have in the above formula (I) is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. The halogen atom as the substituent is preferably a fluorine atom, an iodine atom, or a bromine atom, more preferably an iodine atom or a fluorine atom. Among these, an iodine atom is even more preferable in terms of sensitivity, reduced roughness, and suppression of film loss. The alkyl group as the substituent may be linear or branched, and is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or a tert-butyl group. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with the halogen atoms. Examples of the aryl group as the substituent include an aryl group having 6 to 20 carbon atoms, preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and even more preferably a methoxy group or an ethoxy group. ＡｒThe substituent that the aromatic group in the formula (I) may have is preferably at least one selected from the group consisting of a halogen atom and an alkyl group, and among these, a halogen atom is more preferable in terms of the effects of sensitivity, reduction in roughness, and suppression of film loss.

[0053] Among the above, R Ａｒ As the substituent, it is preferable that the aromatic group may have at least one substituent selected from the group consisting of a halogen atom and an alkyl group, and it is more preferable that the aromatic group may have at least one substituent selected from a halogen atom. In particular, it is even more preferable that the aromatic group has an iodine atom as a substituent, since this tends to improve the effects of sensitivity, reduction of roughness, and suppression of film loss.

[0054] A preferred example of the structural unit (a00) is a structural unit represented by the following general formula (a00-u):

[0055] [In formula (a00-u), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. ０ｃ is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group. p' is an integer of 0 to 4.

[0056] In the formula (a00-u), R ０ａ and R ０ｂ , L ００ represents R in the above general formula (a00). ０ａ and R ０ｂ , L ００ The explanation is the same as for R. ０ａ and R ０ｂ are each preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, and R ０ａ and R ０ｂ It is particularly preferred that all of L are hydrogen atoms. ００is preferably a single bond. p' is an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0 or 1. R ０ｃ is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group, preferably at least one selected from the group consisting of a halogen atom and an alkyl group, more preferably a halogen atom, and among these, from the viewpoints of sensitivity, roughness reduction, and film loss suppression effects, still more preferably an iodine atom. The bonding position of the hydroxy group (-OH) on the benzene ring in formula (a00-u) may be any of the ortho position, meta position, and para position. From the viewpoint of the film loss suppression effects, the bonding position of the hydroxy group (-OH) on the benzene ring is more preferably the ortho position or the meta position. From the viewpoints of sensitivity, roughness reduction, and film loss suppression effects, as well as ease of synthesis, the para position is more preferred.

[0057] Specific examples of the structural unit (a00) are shown below. In each of the following formulas, R ００ａ and R ００ｂ each independently represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0058]

[0059]

[0060] The structural unit (a00) is preferably selected from the group consisting of structural units represented by the above chemical formulas (a00-u1-01) to (a00-u1-14), structural units represented by the above chemical formulas (a00-u2-01) to (a00-u2-14), and structural units represented by the chemical formula (a00-u3-01). Of these, the structural unit (a00) is more preferably selected from the group consisting of structural units represented by the above chemical formulas (a00-u1-01), (a00-u1-06), (a00-u1-07), and (a00-u1-09); structural units represented by the chemical formulas (a00-u2-01), (a00-u2-06), (a00-u2-07), and (a00-u2-08); and structural units represented by the chemical formula (a00-u3-01). In terms of sensitivity, roughness reduction, and film loss suppression effects, structural units selected from the group consisting of structural units represented by the chemical formulas (a00-u1-07) and (a00-u1-09); and structural units represented by the chemical formulas (a00-u2-07) and (a00-u2-08) are even more preferable.

[0061] The structural unit (a00) contained in the component (A1-0) may be of one type, or may be of two or more types. The proportion of the structural unit (a00) in the component (A1-0), relative to the total (100 mol%) of all structural units constituting the component (A1-0), is preferably 5 to 45 mol%, more preferably 10 to 40 mol%, and even more preferably 20 to 35 mol%. By ensuring that the proportion of the structural unit (a00) is at least the lower limit of the above-mentioned preferred range, high sensitivity can be achieved during resist pattern formation, and the effect of reducing roughness can be more easily improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0062] <<Structural Unit (a01)>> The structural unit (a01) is a structural unit represented by the following general formula (a01). This structural unit (a01) is a structural unit that contains an acid-decomposable group whose polarity increases under the action of an acid. In the structural unit (a01), the acid-decomposable group decomposes under the action of an acid to generate a carboxy group.

[0063] [In formula (a01), R ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group.

[0064] In the formula (a01), R ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ The alkyl group having 1 to 5 carbon atoms in the formula (I) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferred. R ０１ As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms is preferred, and a hydrogen atom or a methyl group is more preferred from the viewpoint of industrial availability.

[0065] In the formula (a01), L ０１ is a divalent linking group or a single bond. ０１ Examples of the divalent linking group in formula (a00) include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and a combination thereof. ００ Examples of the divalent hydrocarbon group which may have a substituent, the divalent linking group containing a hetero atom, and combinations thereof are the same as those exemplified in the description of L. ０１ is preferably a single bond, an ester bond [—C(═O)—O—], an aliphatic hydrocarbon group containing a ring in the structure, an aromatic hydrocarbon group, or a combination thereof.

[0066] L ０１In the above, the aliphatic hydrocarbon group containing a ring in its structure is preferably a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure. The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxy group, and a carbonyl group. In the cyclic aliphatic hydrocarbon group, a methylene group constituting the ring structure may be substituted with a divalent group containing a heteroatom. Examples of the divalent group include a carbonyl group, an ether bond [—O—], an ester bond [—C(═O)—O—], —S—, and —S(═O) ２ -, -S(=O) ２ Examples include —O—, an amide group [—C(═O)—NH—], and an imino group [—NH—].

[0067] L ０１ In the above formula, the aromatic hydrocarbon group is preferably a group (arylene group or heteroarylene group) in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring or an aromatic heterocycle. In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent.

[0068] In the formula (a01), R Ｘ is an acid-dissociable group. Ｘ Examples of the acid-dissociable group in include those that have been proposed as acid-dissociable groups for base resins for chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed as acid-dissociable groups for base resins for chemically amplified resist compositions include the "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," and "secondary alkyl ester-type acid-dissociable groups" described below.

[0069] Acetal-type acid-dissociable group: R Ｘ Examples of the acid-dissociable group in the formula (a1-r-1) include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter, sometimes referred to as "acetal-type acid-dissociable group").

[0070] [In the formula, Ra' １ and Ra'２ are each a hydrogen atom or an alkyl group. ３ is a hydrocarbon group, and Ra' ３ is Ra' １ , Ra' ２ may be bonded to any one of the following to form a ring.]

[0071] In formula (a1-r-1), Ra' １ and Ra' ２ Among Ra', at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. １ or Ra' ２ When is an alkyl group, the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. Specific examples thereof include linear and branched alkyl groups. More specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. A methyl group or an ethyl group is more preferred, and a methyl group is particularly preferred.

[0072] In formula (a1-r-1), Ra' ３ Examples of the hydrocarbon group include a linear or branched alkyl group, and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and the like. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred. The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and the like, with an isopropyl group being preferred.

[0073] Ra' ３When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a monocyclic group or a polycyclic group. As an aliphatic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an aliphatic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ ]decane, tetracyclododecane, and the like.

[0074] Ra' ３ When the cyclic hydrocarbon group described above becomes an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Ra' ３Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (an aryl group or a heteroaryl group); a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0075] Ra' ３ The cyclic hydrocarbon group in may have a substituent. Examples of the substituent include -R Ｐ１ , -R Ｐ２ -O-R Ｐ１ , -R Ｐ２ -CO-R Ｐ１ , -R Ｐ２ -CO-OR Ｐ１ , -R Ｐ２ -O-CO-R Ｐ１ , -R Ｐ２ -OH, -R Ｐ２ -CN or -R Ｐ２ -COOH (hereinafter, these substituents are collectively referred to as "Ra ｘ５ ") etc. Here, R Ｐ１ is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ２ is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ１ and R Ｐ２Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the aliphatic cyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The aliphatic cyclic hydrocarbon group may have one or more of one type of the above-mentioned substituents, or may have one or more of each of two or more types of the above-mentioned substituents. Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group; a bicyclo[2.2.2]octanyl group, a tricyclo[5.2.1.0]octanyl group, and the like. ２，６ ]decanyl group, tricyclo[3.3.1.1 ３，７ ] decanyl group, tetracyclo[6.2.1.1 ３，６ .0 ２，７ Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene.

[0076] Ra' ３ But Ra' １ , Ra' ２ When the cyclic group is bonded to any one of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0077] Tertiary alkyl ester type acid-dissociable group: R Ｘ Examples of the acid-dissociable group in the formula (a1-r-2) include acid-dissociable groups represented by the following general formula (a1-r-2): Of the acid-dissociable groups represented by the formula (a1-r-2) below, those constituted by an alkyl group may hereinafter be referred to as "tertiary alkyl ester-type acid-dissociable groups" for convenience.

[0078] [In the formula, Ra' ４ ~Ra' ６ are each independently a hydrocarbon group which may have a substituent, and Ra' ５ and Ra' ６ may be bonded to each other to form a ring.

[0079] Ra' ４ Examples of the hydrocarbon group of Ra' include a linear or branched alkyl group which may have a substituent, a linear or cyclic alkenyl group which may have a substituent, and a cyclic hydrocarbon group which may have a substituent. ４ The linear or branched alkyl group and the cyclic hydrocarbon group (a monocyclic aliphatic hydrocarbon group, a polycyclic aliphatic hydrocarbon group, and an aromatic hydrocarbon group) in ３ The same as Ra' can be mentioned. ４ The chain or cyclic alkenyl group in Ra' is preferably an alkenyl group having 2 to 10 carbon atoms. ５ , Ra' ６ The hydrocarbon group of Ra' ３ The same can be mentioned.

[0080] Ra' ５ and Ra' ６ When Ra' is bonded to each other to form a ring, preferred examples thereof include a group represented by the following general formula (a1-r2-1), a group represented by the following general formula (a1-r2-2), and a group represented by the following general formula (a1-r2-3). ４ ~Ra' ６ When the groups are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0081] [In formula (a1-r2-1), Ra' １０ represents a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. １１ is Ra' １０represents a group which forms an aliphatic cyclic group together with the carbon atom to which it is bonded. In formula (a1-r2-2), Ya is a carbon atom. Xa is a group which forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Some of the carbon atoms constituting the ring of this cyclic hydrocarbon group may be substituted with a heteroatom-containing group. Ra １０１ ~Ra １０３ are each independently a hydrogen atom, a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent cyclic aliphatic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms in the linear saturated hydrocarbon group and the cyclic aliphatic saturated hydrocarbon group may be substituted. １０１ ~Ra １０３ Two or more of the above may be bonded to each other to form a cyclic structure. In formula (a1-r2-3), Yaa is a carbon atom. Xaa is a group that forms an aliphatic cyclic group together with Yaa. Ra １０４ In formula (a1-r2-4), Ra′ is an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent. １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms of this chain saturated hydrocarbon group may be substituted. １４ is a hydrocarbon group which may have a substituent. * indicates a bond (the same applies hereinafter).

[0082] In the above formula (a1-r2-1), Ra' １０ is a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. １０ The linear alkyl group in Ra' has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. １０ In the formula (I), the branched alkyl group is the above-mentioned Ra' ３ The same can be mentioned.

[0083] Ra' １０In the above, the alkyl group may be partially substituted with a halogen atom or a heteroatom-containing group. For example, some of the hydrogen atoms constituting the alkyl group may be substituted with a halogen atom or a heteroatom-containing group. Furthermore, some of the carbon atoms (such as methylene groups) constituting the alkyl group may be substituted with a heteroatom-containing group. Examples of the heteroatom include an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the heteroatom-containing group include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -S-, and -S(=O) ２ -, -S(=O) ２ -O- and the like.

[0084] In formula (a1-r2-1), Ra' １１ (Ra' １０ The aliphatic cyclic group formed together with the carbon atom to which Ra' is bonded in formula (a1-r-1) is ３ Among these, a monocyclic alicyclic hydrocarbon group is preferred, and specifically, a cyclopentyl group, a cyclohexyl group, or a tetrahydrofuranyl group is more preferred. １１ In the formula (I), some of the carbon atoms constituting the ring may be substituted with a heteroatom-containing group. Examples of the heteroatom-containing group include the same as those mentioned above.

[0085] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0086]

[0087]

[0088]

[0089]

[0090] In the formula (a1-r2-2), the cyclic hydrocarbon group formed by Xa together with Ya includes Ra' in the formula (a1-r-1). ３Examples of the cyclic hydrocarbon group include groups in which one or more hydrogen atoms have been further removed from the cyclic monovalent hydrocarbon group (aliphatic hydrocarbon group) in the above formula. Among these, monocyclic alicyclic hydrocarbon groups are preferred, and specifically, cyclopentyl and cyclohexyl groups are more preferred. The cyclic hydrocarbon group formed by Xa together with Ya may have a substituent. Examples of the substituent include the above Ra' ３ In formula (a1-r2-2), the substituents that the cyclic hydrocarbon group in formula (a1-r2-2) may have are the same as those in formula (a1-r2-2). １０１ ~Ra １０３ In the formula, examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. １０１ ~Ra １０３ In the above formula, examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group; ２，６ ]decanyl group, tricyclo[3.3.1.1 ３，７ ] decanyl group, tetracyclo[6.2.1.1 ３，６ .0 ２，７ ] and polycyclic aliphatic saturated hydrocarbon groups such as a dodecanyl group and an adamantyl group. １０１ ~Ra １０３ Among these, from the viewpoint of ease of synthesis, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferable, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferable, and a hydrogen atom is particularly preferable.

[0091] The above Ra １０１ ~Ra １０３ Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula (I) include the above-mentioned Ra ｘ５ The same groups as those shown below can be mentioned.

[0092] Ra １０１ ~Ra １０３Examples of the group containing a carbon-carbon double bond formed by two or more of the above being bonded to each other to form a cyclic structure include a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclohexenyl group, a cyclopentylidene-ethenyl group, a cyclohexylidene-ethenyl group, etc. Among these, from the viewpoint of ease of synthesis, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred.

[0093] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0094]

[0095]

[0096]

[0097] In formula (a1-r2-3), the aliphatic cyclic group formed by Xaa together with Yaa is Ra' in formula (a1-r-1). ３ The groups exemplified as the aliphatic hydrocarbon group, which is a monocyclic or polycyclic group of the formula (a1-r2-3), are preferred. In the aliphatic cyclic group, some of the carbon atoms constituting the ring may be substituted with a heteroatom-containing group. Examples of the heteroatom-containing group include the same as those mentioned above. The aliphatic cyclic group formed by Xaa together with Yaa is preferably a monocyclic group, more preferably a cyclopentyl group, a cyclohexyl group, or a tetrahydrofuranyl group. In formula (a1-r2-3), Ra １０４ Examples of the aromatic hydrocarbon group in the formula (I) include a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 5 to 30 carbon atoms. １０４ is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from benzene or naphthalene, and most preferably a group in which one or more hydrogen atoms have been removed from benzene. １０４The aromatic heterocyclic group in the formula (I) includes those containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

[0098] Ra in formula (a1-r2-3) １０４ Examples of the substituent that may be possessed by the group include a methyl group, an ethyl group, a propyl group, a hydroxy group, a carboxy group, a halogen atom, an alkoxy group (e.g., a methoxy group, an ethoxy group, a propoxy group, a butoxy group), an alkyloxycarbonyl group, and the like.

[0099] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0100]

[0101]

[0102] In formula (a1-r2-4), Ra' １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. １２ and Ra' １３ In the formula (I), the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Ra １０１ ~Ra １０３ The monovalent saturated chain hydrocarbon group having 1 to 10 carbon atoms in the formula (1) may be substituted in part or in whole. １２ and Ra' １３ Among these, Ra' is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. １２ and Ra' １３ In the case where the chain saturated hydrocarbon group represented by the formula: ｘ５ The same groups as those shown below can be mentioned.

[0103] In formula (a1-r2-4), Ra' １４ is a hydrocarbon group which may have a substituent. １４The hydrocarbon group in the formula (I) includes a linear or branched alkyl group, or a cyclic hydrocarbon group.

[0104] Ra' １４ The linear alkyl group in the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0105] Ra' １４ The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, and more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0106] Ra' １４ When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a monocyclic group or a polycyclic group. As an aliphatic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an aliphatic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ ]decane, tetracyclododecane, and the like.

[0107] Ra' １４ As the aromatic hydrocarbon group in １０４ Among them, the aromatic hydrocarbon groups Ra' are the same as those in １４is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from naphthalene or anthracene, and most preferably a group in which one or more hydrogen atoms have been removed from naphthalene. １４ Examples of the substituent that may be possessed by Ra include １０４ Examples of the substituents include the same as those that may be possessed by the group.

[0108] Ra' in formula (a1-r2-4) １４ When Ra' in formula (a1-r2-4) is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. １４ When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be any one of the 1st, 2nd, and 9th positions of the anthryl group.

[0109] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0110]

[0111] Secondary alkyl ester type acid-dissociable group: R Ｘ Examples of the acid-dissociable group in the formula (a1-r-4) include acid-dissociable groups represented by the following general formula (a1-r-4).

[0112] [In the formula, Ra' １０ is a hydrocarbon group which may have a substituent. １１ａ and Ra' １１ｂ Each of Ra' independently represents a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent. １２ represents a hydrogen atom or a hydrocarbon group which may have a substituent. １０ and Ra' １１ａ or Ra' １１ｂ and may be bonded to each other to form a ring. １１ａ or Ra'１１ｂ and Ra' １２ may be bonded to each other to form a ring.

[0113] In the formula, Ra' １０ and Ra' １２ The hydrocarbon group in Ra' is ３ In the formula, Ra' １１ａ and Ra' １１ｂ The alkyl group in Ra' is １ In the formula, Ra' １０ and Ra' １２ and the hydrocarbon group in Ra' １１ａ and Ra' １１ｂ The hydrocarbon group in may have a substituent. Examples of the substituent include a hydroxy group, an alkoxy group, and the above-mentioned Ra ｘ５ etc.

[0114] Ra' １０ and Ra' １１ａ or Ra' １１ｂ may be bonded to each other to form a ring. The ring may be polycyclic or monocyclic, and may be an alicyclic or aromatic ring. The alicyclic and aromatic rings may contain heteroatoms. The heteroatoms may be contained in a group substituting a hydrogen atom in the alicyclic or aromatic ring, or may be contained in a group substituting a carbon atom in the alicyclic or aromatic ring.

[0115] Ra' １０ and Ra' １１ａ or Ra' １１ｂ and are bonded to each other to form a ring, among the above, a monocycloalkene, a ring in which a portion of the carbon atoms of a monocycloalkene is substituted with a heteroatom (such as an oxygen atom or a sulfur atom), or a monocycloalkadiene is preferred, a cycloalkene having 3 to 6 carbon atoms is preferred, and cyclopentene or cyclohexene is preferred.

[0116] Ra' １０ and Ra' １１ａ or Ra' １１ｂThe ring formed by bonding these may be a fused ring. The fused ring is preferably a fused ring of an aliphatic ring and an aromatic ring, and specific examples thereof include indane, tetralin, and chroman.

[0117] Ra' １０ and Ra' １１ａ or Ra' １１ｂ The ring formed by bonding together may have a substituent. Examples of the substituent include a hydroxy group, an alkoxy group, and the above-mentioned Ra ｘ５ etc.

[0118] Ra' １１ａ or Ra' １１ｂ and Ra' １２ and may be bonded to each other to form a ring, and the ring may include Ra' １０ and Ra' １１ａ or Ra' １１ｂ and the ring formed by bonding with each other are exemplified.

[0119] Specific examples of the group represented by the formula (a1-r-4) are listed below.

[0120]

[0121]

[0122] Among the above, R Ｘ The acid-dissociable group in the formula (a01) is Ｘ However, an acid-dissociable group bonded to the oxygen atom (-O-) in -C(=O)-O- in formula (a01) via a carbon atom and having a carbon-carbon unsaturated bond formed between the α-position of the carbon atom and the β-position of the carbon atom is preferred. Suitable examples of such an acid-dissociable group include the groups represented by the above-mentioned general formula (a1-r2-2) and the acid-dissociable groups represented by the general formula (a1-r-4), which are likely to contribute to high sensitivity and an enhanced effect of reducing roughness. Furthermore, a suitable example of an acid-dissociable group that is likely to contribute to an enhanced effect of suppressing film loss is the group represented by the above-mentioned general formula (a1-r2-2).

[0123] Preferred examples of the structural unit (a01) include structural units represented by the following general formula (a1-1) or (a1-3).

[0124] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １ is a divalent hydrocarbon group which may have an ether bond. ａ１ is an integer from 0 to 2. １ represents an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). ００１ represents a single bond or a divalent linking group. ０１ is a single bond or a divalent linking group. ０１ is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). ０１ is an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group; q is an integer of 0 to 3; and n is an integer of 0 or greater, provided that n≦q×2+4.

[0125] In the formulas (a1-1) and (a1-3), the alkyl group having 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. A fluorine atom is particularly preferred as the halogen atom. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the perspective of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0126] In the formula (a1-1), Va １ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0127] Va １ The aliphatic hydrocarbon group as the divalent hydrocarbon group in may be saturated or unsaturated, and is usually preferably saturated. More specific examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0128] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0129] Examples of the aliphatic hydrocarbon group containing a ring in its structure include alicyclic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as the linear aliphatic hydrocarbon group or the branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. A preferred monocyclic alicyclic hydrocarbon group is a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ]decane, tetracyclododecane, and the like.

[0130] Va １ In the above, the aliphatic hydrocarbon group containing a ring in its structure may be a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure. The cyclic aliphatic hydrocarbon group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxy group, and a carbonyl group. In the cyclic aliphatic hydrocarbon group, a methylene group constituting the ring structure may be substituted with a divalent group containing a heteroatom. Examples of the divalent group include a carbonyl group, an ether bond [—O—], an ester bond [—C(═O)—O—], —S—, and —S(═O) ２ -, -S(=O) ２-O-, an amide group [-C(=O)-NH-], an imino group [-NH-], etc. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, and -SO groups represented by the general formulae (b5-r-1) to (b5-r-4) described below. ２ -containing cyclic groups.

[0131] Va １ The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such an aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (an arylene group); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (an aryl group) has been substituted with an alkylene group (for example, a group in which one further hydrogen atom has been removed from the aryl group of an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0132] In the formula (a1-1), Ra １ is preferably an acid-dissociable group represented by the above general formula (a1-r-2) or (a1-r-4), and among these, a group represented by the general formula (a1-r2-2) or an acid-dissociable group represented by the general formula (a1-r-4) is more preferred.

[0133] In the formula (a1-3), Ya ００１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ００１ is preferably an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Among these, Ya ００１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0134] In the formula (a1-3), Ya ０１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ０１ Among the above, it is preferable that Ya is an ester bond [—C(═O)—O—, —O—C(═O)—], an ether bond (—O—), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. ０１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0135] In the formula (a1-3), Rax ０１ is preferably an acid dissociable group represented by the above general formula (a1-r-2) or (a1-r-4), and among these, an acid dissociable group represented by the general formula (a1-r-2) is more preferred, and a group represented by the general formula (a1-r2-1) is even more preferred.

[0136] In the formula (a1-3), Rz ０１The alkyl group, halogenated alkyl group, and alkoxy group in Rz preferably have 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, even more preferably 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms. The alkyl group, halogenated alkyl group, and alkoxy group may be linear or branched. ０１ The halogen atom in Rz is preferably an iodine atom or a bromine atom. ０１ The halogen atom of the halogenated alkyl group in Rz is preferably a fluorine atom, an iodine atom, or a bromine atom, and more preferably a fluorine atom. ０１ As the alkyl group, an alkoxy group or a hydroxy group is preferred, and a hydroxy group is more preferred.

[0137] In the formula (a1-3), q is an integer of 0 to 3. When q is 0, the structure is a benzene structure, when q is 1, the structure is a naphthalene structure, when q is 2, the structure is an anthracene structure, and when q is 3, the structure is a tetracene structure. In the formula (a1-3), n is an integer of 0 or more, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, and even more preferably 1 or 2. When n is an integer of 2 or more, Rz is 2 or more. ０１ may be the same or different. In the formula (a1-3), n≦q×2+4. For example, when q is 1 and the naphthalene structure is formed, all six hydrogen atoms of the naphthalene are Rz ０１ In addition, in the naphthalene, Ya ００１ , -Ya ０１ -C(=O)-O-Rax ０１ group, and Rz ０１ The substitution position of is not particularly limited.

[0138] Specific examples of the structural unit (a01) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. Each Rz independently represents a hydrogen atom, an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group.

[0149]

[0150]

[0151]

[0152]

[0153]

[0154] As the structural unit (a01), a structural unit represented by the formula (a1-1) or a structural unit represented by the formula (a1-3) is more preferred because these structural units are more likely to provide improved properties (sensitivity, shape, etc.) in electron beam or EUV lithography. Among these, an acid-dissociable group (Ra １ , Rax ０１ ) are preferably acid-dissociable groups represented by the above general formula (a1-r2-1), general formula (a1-r2-2) or general formula (a1-r-4), respectively. Among these, the acid-dissociable group is preferably R Ｘis preferably an acid-dissociable group bonded to the oxygen atom (-O-) in -C(=O)-O- in formula (a01) via a carbon atom, and having a carbon-carbon unsaturated bond formed between the α-position of the carbon atom and the β-position of the carbon atom. Suitable examples of such acid-dissociable groups include the groups represented by the general formula (a1-r2-2) and the general formula (a1-r-4) described above, which are likely to contribute to high sensitivity and an enhanced effect of reducing roughness. Furthermore, the group represented by the general formula (a1-r2-2) described above is suitable as an acid-dissociable group that is likely to also enhance the effect of suppressing film loss.

[0155] The structural unit (a01) contained in the component (A1-0) may be of one type, or may be of two or more types. The proportion of the structural unit (a01) in the component (A1-0), relative to the total (100 mol%) of all structural units constituting the component (A1-0), is preferably 25 to 75 mol%, more preferably 40 to 70 mol%, and even more preferably 50 to 65 mol%. By ensuring that the proportion of the structural unit (a01) is at least the lower limit of the above-mentioned preferred range, etching resistance is likely to be improved. In addition, lithography properties such as reduced roughness of the resist pattern are likely to be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, resulting in various improved lithography properties.

[0156] <Structural Unit (a02)> The structural unit (a02) is represented by the following general formula (a02), and is a structural unit that generates acid upon exposure. In the resist composition of this embodiment, the structural unit (a02) is combined with other compounds such that the acid generated upon exposure is converted to an acid-dissociable group (R Ｘ ) or may control the diffusion of acids generated from other compounds.

[0157] [In formula (a02), R ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ is a divalent linking group. － is an anionic group. ｍ＋is an m-valent onium cation, where m is an integer of 1 or more.

[0158] [Anion moiety] In the formula (a02), R ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ The alkyl group having 1 to 5 carbon atoms in the formula (I) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferred. R ０２ As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms is preferred, and a hydrogen atom or a methyl group is more preferred from the viewpoint of industrial availability.

[0159] In the formula (a02), L ０２ is a divalent linking group. ０２ Examples of the divalent linking group in formula (a00) include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and a combination thereof. ００ Examples of the divalent hydrocarbon group which may have a substituent, the divalent linking group containing a hetero atom, and combinations thereof are the same as those exemplified in the description of L. ０２is preferably a cyclic aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), an amide bond [-NH-C(=O)-, -C(=O)-NH-], a linear or branched aliphatic hydrocarbon group, a linear or branched fluorinated aliphatic hydrocarbon group, or a combination of two or more thereof; and more preferably a cyclic aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an ester bond [-C(=O)-O-, -O-C(=O)-], a linear or branched aliphatic hydrocarbon group, a linear or branched fluorinated aliphatic hydrocarbon group, or a combination of two or more thereof.

[0160] In the formula (a02), Z － is an anionic group. － Examples of the anion group in include those having a sulfonate anion structure, a carboxylate anion structure, an imide anion structure, a methide anion structure, a carbonate anion structure, a borate anion structure, a halogen anion structure, a phosphate anion structure, an antimonate anion structure, an arsenate anion structure, etc. Among these, those having a sulfonate anion structure, a carboxylate anion structure, an imide anion structure, or a methide anion structure are preferred, those having a sulfonate anion structure or a carboxylate anion structure are more preferred, and those having a sulfonate anion structure, i.e., a sulfonate ion, are particularly preferred.

[0161] A preferred example of the structural unit (a02) is a structural unit represented by the following general formula (a02-u):

[0162] [In the formula, R ０２ represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ represents a divalent linking group or a single bond. ０１ represents a hydrocarbon group which may have a substituent. ０２ represents a divalent linking group or a single bond. ０１represents a fluorinated alkylene group, an alkylene group, or a single bond. ０２ and Va ０１ and R cannot both be single bonds. ０３ and R ０４ are each independently a fluorinated alkyl group, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0163] In the formula (a02-u), R ０２ The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. ０２ The halogenated alkyl group having 1 to 5 carbon atoms in the formula (I) is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. The halogen atom is preferably a fluorine atom. ０２ is preferably a hydrogen atom or a methyl group because of industrial availability.

[0164] In the formula (a02-u), Yx ０１ The divalent linking group in ０２ Examples of the divalent linking group include the same as the divalent linking groups exemplified in the description of the divalent linking group in Yx. ０１ Specific examples of the alkylene group include an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an ether bond (-O-), a linear or branched alkylene group, an arylene group which may have a substituent, any combination thereof, or a single bond. A combination of an arylene group which may have a substituent and an ester bond (-C(=O)-O-), an ester bond (-C(=O)-O-), or a single bond is preferred, and a combination of a phenylene group which may have a substituent and an ester bond (-C(=O)-O-), or an ester bond (-C(=O)-O-).

[0165] In the formula (a02-u), La０１ As the group, L in the above-mentioned formula (a00) ００ Examples of the divalent hydrocarbon group that may have a substituent include the same aliphatic hydrocarbon groups (chain-like aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in the structure) and aromatic hydrocarbon groups exemplified in the description of the divalent hydrocarbon group that may have a substituent in (1). Among these, aliphatic hydrocarbon groups that contain a ring in the structure and aromatic hydrocarbon groups are preferred, and cyclic aliphatic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) and aromatic hydrocarbon groups that may have a substituent are more preferred.

[0166] La ０１ The cyclic aliphatic hydrocarbon group in may be a monocyclic alicyclic hydrocarbon group or a polycyclic alicyclic hydrocarbon group, preferably a polycyclic alicyclic hydrocarbon group, more preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and even more preferably a group in which two hydrogen atoms have been removed from adamantane. The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxy group, and a carbonyl group. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom. Examples of the substituent containing a heteroatom include -O-, -C(=O)-O-, -S-, and -S(=O) ２ -, -S(=O) ２ —O— is preferred.

[0167] La ０１ The aromatic hydrocarbon group in the formula (I) is preferably a group (arylene group or heteroarylene group) in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring or an aromatic heterocycle, more preferably an arylene group, and even more preferably a phenylene group. The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to the aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxy group.

[0168] Among the above, La ０１ is preferably an aromatic hydrocarbon group which may have a substituent, or a cyclic aliphatic hydrocarbon group which may have a substituent, and more preferably an arylene group which may have a substituent, or a polycyclic alicyclic hydrocarbon group which may have a substituent.

[0169] In the formula (a02-u), Ya ０２ As the divalent linking group in the formula (a00), ００ Examples of the divalent linking group containing a hetero atom include those similar to those in the above formula. ０２ is preferably an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—), or an oxycarbonyl group (—O—C(═O)—), and (La ０１ side) -C(=O)-O-(Va ０１ It is more preferable that the side is the side.

[0170] In the formula (a02-u), Va ０１ The alkylene group in the formula (a00) is preferably L ００ Examples of the linear or branched aliphatic hydrocarbon group include those similar to those in the above formula. ０１ As the fluorinated alkylene group in ０１ In the above formula, some or all of the hydrogen atoms constituting the alkylene group are substituted with fluorine atoms. ０１ is preferably a fluorinated alkylene group having 1 to 4 carbon atoms, an alkylene group having 1 to 4 carbon atoms, or a single bond, and is preferably a methylene group (—CH ２ -), -CH(CF ３ )- is particularly preferred.

[0171] In the formula (a02-u), R ０３ and R ０４ are each independently a fluorinated alkyl group, a fluorine atom, or a hydrogen atom. ０３ and R ０４ are each independently preferably a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, more preferably a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom, and more preferably a fluorine atom.

[0172] Specific examples of the structural unit (a02) are shown below, but the structural unit is not limited to these. In each of the formulas shown below, R α represents a trifluoromethyl group, a methyl group, or a hydrogen atom. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0173]

[0174]

[0175]

[0176]

[0177] The structural unit (a02) is preferably a structural unit selected from the group consisting of structural units represented by any one of the formulas (a02-u-01) to (a02-u-05), structural units represented by any one of the formulas (a02-u-06) to (a02-u-16), and structural units represented by any one of the formulas (a02-u-17) to (a02-u-23), and structural units represented by any one of the formulas (a02-u-06) to (a02-u-16), and structural units selected from the group consisting of structural units represented by any one of the formulas (a02-u-17) to (a02-u-23), more preferably a structural unit selected from the group consisting of structural units represented by any one of the formulas (a02-u-17) to (a02-u-23), and even more preferably a structural unit selected from the group consisting of structural units represented by any one of the formulas (a02-u-23), and particularly preferably a structural unit represented by the formula (a02-u-23).

[0178] [Cation moiety] In the formula (a02), M ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. ｍ＋ Among the onium cations in the formula (M), sulfonium cations and iodonium cations are preferred, and sulfonium cations are more preferred. ｍ＋ ) １／ｍ Examples of the onium cation include those represented by the following general formulas (ca-1) to (ca-3).

[0179] [In the formula, R ２０１ ~R２０７ R each independently represents an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. ２０１ ~R ２０３ , R ２０６ ~R ２０７ may be bonded to each other to form a ring together with the sulfur atom in the formula. ２０８ ~R ２０９ R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２０１ represents —C(═O)— or —C(═O)—O—.]

[0180] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０７ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２０１ ~R ２０７ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２０１ ~R ２０７ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２０１ ~R ２０７ , and R ２１０ Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulas (car-r-1) to (car-r-8), respectively. Among these, an alkyl group, a halogen atom, a halogenated alkyl group, and groups represented by the following general formulas (car-r-1) to (car-r-8), respectively, are preferred, and a chain alkyl group, an iodine atom, a fluorine atom, a fluorinated alkyl group, and a group represented by the following general formula (car-r-3), respectively, are more preferred.

[0181] [In the formula, R' ２０１are each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0182] Cyclic group which may have a substituent: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0183] R' ２０１ The aromatic hydrocarbon group in R' is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. ２０１ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R' include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. ２０１ Specific examples of the aromatic hydrocarbon group in the formula (I) include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0184] R' ２０１Examples of the cyclic aliphatic hydrocarbon group in the formula (I) include aliphatic hydrocarbon groups containing a ring within their structure. Examples of aliphatic hydrocarbon groups containing a ring within their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed within a linear or branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be either a polycyclic group or a monocyclic group. Preferred monocyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a monocycloalkane. Preferred monocycloalkanes have 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. Preferred polycyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a polycyclic skeleton of a bridged ring system, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a polycyclic skeleton of a fused ring system, such as a cyclic group having a steroid skeleton.

[0185] Among them, R' ２０１ The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0186] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ )２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specifically, —CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0187] Also, R' ２０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, —SO 4 groups represented by the general formulae (b5-r-1) to (b5-r-4) described below, ２ -containing cyclic groups, and heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16).

[0188]

[0189] R' ２０１ Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. The halogen atom as a substituent is preferably a fluorine atom or an iodine atom. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH ２ -) is a group that substitutes

[0190] A chain alkyl group which may have a substituent: R' ２０１The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0191] A chain alkenyl group which may have a substituent: R' ２０１ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of linear alkenyl groups include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of branched alkenyl groups include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the above chain alkenyl groups, linear alkenyl groups are preferred, with a vinyl group and a propenyl group being more preferred, and a vinyl group being particularly preferred.

[0192] R' ２０１ Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, the above-mentioned R' ２０１ Examples of the cyclic groups include the cyclic groups shown in the formula:

[0193] R' ２０１In addition to the above-mentioned optionally substituted cyclic groups, optionally substituted chain alkyl groups, and optionally substituted chain alkenyl groups, examples of the optionally substituted cyclic groups or optionally substituted chain alkyl groups include those similar to the acid-dissociable group represented by formula (a1-r-2) above.

[0194] Among them, R' ２０１ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane; a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7) described below; -SO represented by each of the general formulae (b5-r-1) to (b5-r-4) described below; ２ For example, from the viewpoint of achieving high sensitivity when forming a resist pattern, an aromatic hydrocarbon group which may have a substituent is preferred, an aromatic hydrocarbon group having an iodine atom bonded as a substituent is more preferred, and a benzene ring having an iodine atom bonded as a substituent is particularly preferred.

[0195] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０３ , R ２０６ ~R ２０７ When they are bonded to each other to form a ring together with the sulfur atom in the formula, they are not substituted with heteroatoms such as sulfur atoms, oxygen atoms, and nitrogen atoms, or with carbonyl groups, -SO-, -SO ２ -, -SO ３ -, -COO-, -CONH- or -N(R Ｎ )-(the R Ｎis an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0196] R ２０８ ~R ２０９ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0197] R ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２１０ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２１０ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２１０ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２１０ In the -SO ２ The -containing cyclic group is not particularly limited and any group can be used. Specific examples include groups represented by the following general formulae (b5-r-1) to (b5-r-4), and "-SO ２ -containing polycyclic group" is preferred, and a group represented by general formula (b5-r-1) is more preferred.

[0198] [In the formula, Rb' ５１are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, or —SO ２ -containing cyclic group; B" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; n' is an integer of 0 to 2; * represents a bond.

[0199] In the general formulae (b5-r-1) and (b5-r-2), B" represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom. B" is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably a methylene group.

[0200] In the general formulae (b5-r-1) to (b5-r-4), Rb' ５１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group, and among these, are preferably each independently a hydrogen atom or a cyano group.

[0201] Specific examples of the groups represented by general formulas (b5-r-1) to (b5-r-4) are listed below, where "Ac" represents an acetyl group.

[0202]

[0203]

[0204]

[0205] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas.

[0206]

[0207]

[0208] [In the formula, g1, g2, and g3 represent the number of repeating units, where g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 1 to 20.]

[0209]

[0210]

[0211] [In the formula, R” ２０１ is a hydrogen atom or a substituent, and the substituent is the same as R ２０１ ~R ２０７ and R ２１０ The substituents are the same as those exemplified as the substituents that may be possessed by

[0212]

[0213]

[0214] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0215] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0216]

[0217] The cation moiety ((M ｍ＋ ) １／ｍ) are more preferably cations represented by the formulas (ca-1) to (ca-3), and the cations represented by the formulas (ca-1-1) to (ca-1-87) are particularly preferred; diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation. Among these, the cation represented by the formula (ca-1) is preferred, and particularly from the viewpoint of increasing sensitivity, suitable cations represented by the formula (ca-1) are preferably those having an electron-withdrawing group such as a fluorine atom, a fluorinated alkyl group, or a sulfonyl group as a substituent; or an iodine atom, and for example, cations selected from the group consisting of the cations represented by the above chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84), and (ca-1-85) to (ca-1-87) are particularly preferred. The number of substituents in the entire cation moiety may be, for example, 1 to 6, and may be 2 to 6, or may be 3 to 6. Among the above, M in the formula (a02) is preferred because it is likely to enhance the effects of reducing sensitivity and roughness. ｍ＋ is preferably an m-valent onium cation having a fluorine atom, and for example, a cation selected from the group consisting of the cations represented by the above chemical formulas (ca-1-71) to (ca-1-75) is more preferred, a cation selected from the group consisting of the cations represented by the above chemical formulas (ca-1-72), (ca-1-74), and (ca-1-75) is even more preferred, and a cation selected from the group consisting of the cations represented by the above chemical formulas (ca-1-74) and (ca-1-75) is particularly preferred.

[0218] Specific examples of the structural unit (a02) include, but are not limited to, the following: α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0219]

[0220] The structural unit (a02) is preferably a structural unit selected from the group consisting of structural units represented by any one of formulas (a02-1) to (a02-6) above, and because this tends to enhance the sensitivity and roughness reduction effects, a structural unit selected from the group consisting of structural units represented by any one of formulas (a02-3) to (a02-5) above is more preferred, and a structural unit selected from the group consisting of structural units represented by any one of formulas (a02-4) to (a02-5) above is even more preferred.

[0221] The structural unit (a02) contained in the component (A1-0) may be of one type, or may be of two or more types. ｍ＋ is an m-valent onium cation having a fluorine atom, and Z － However, a structural unit that is a sulfonate ion is preferred. The proportion of the structural unit (a02) within the component (A1-0) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, and even more preferably 5 to 15 mol %, based on the total (100 mol %) of all structural units constituting the component (A1-0). By ensuring that the proportion of the structural unit (a02) is at least as large as the lower limit of the aforementioned preferred range, etching resistance is likely to be improved. In addition, lithography properties such as reduced roughness of the resist pattern are likely to be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0222] <<Other Structural Units>> The component (A1-0) may be a copolymer that contains, as necessary, other structural units in addition to the aforementioned structural units (a00), (a01), and (a02). Examples of other structural units include a structural unit (a1) (excluding those that fall under the category of structural unit (a01)) containing an acid-decomposable group whose polarity increases under the action of acid; a structural unit (a10) represented by general formula (a10-1) described below; a structural unit (a2) containing a lactone-containing cyclic group; and a structural unit (a8) derived from a compound represented by general formula (a8-1) described below.

[0223] Regarding the structural unit (a1): The structural unit (a1) is a structural unit (excluding those corresponding to the structural unit (a01)) that contains an acid-decomposable group whose polarity increases under the action of acid. Examples of the acid-dissociable group that constitutes this acid-decomposable group include "acetal-type acid-dissociable groups" and "tertiary alkyloxycarbonyl acid-dissociable groups." Examples of the acetal-type acid-dissociable groups include acid-dissociable groups represented by the above general formula (a1-r-1). Examples of the tertiary alkyloxycarbonyl acid-dissociable groups include acid-dissociable groups represented by the following general formula (a1-r-3):

[0224] [In the formula, Ra' ７ ~Ra' ９ are each an alkyl group.

[0225] In formula (a1-r-3), Ra' ７ ~Ra' ９ are each preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. The total number of carbon atoms in each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

[0226] Examples of the structural unit (a1) include structural units derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and structural units in which at least a portion of the hydrogen atoms in the hydroxyl groups of a structural unit derived from hydroxystyrene or a hydroxystyrene derivative are protected with a substituent containing the acid-decomposable group. Among the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. Specific examples of such structural units (a1) include structural units represented by the following general formula (a1-2):

[0227] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １ is (n ａ２ +1) valent hydrocarbon group.ａ２ is an integer from 1 to 3. ２ is an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3).

[0228] In the formula (a1-2), the alkyl group having 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. A fluorine atom is particularly preferred as the halogen atom. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0229] In the formula (a1-2), Wa １ In (n ａ２ The (+1)-valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in the structure, and groups that combine linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in the structure. ａ２ The valence of Ra is preferably 2 to 4, more preferably 2 or 3. ２ is preferably an acid-dissociable group represented by the above general formula (a1-r-1).

[0230] When the component (A1-0) contains the structural unit (a1), the amount of the structural unit (a1) within the component (A1-0) is preferably no greater than 20 mol %, relative to the total amount (100 mol %) of all structural units constituting the component (A1-0). By containing the structural unit (a1) in an amount no greater than the upper limit of the aforementioned preferred range, it becomes easier to form a resist pattern that exhibits excellent lithography properties, such as high sensitivity, high resolution, reduced roughness, and suppressed film loss.

[0231] Regarding the structural unit (a10): The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0232] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ｘ１ is a single bond or a divalent linking group. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ is an integer of 1 or greater.

[0233] In the formula (a10-1), R is the same as R in the formulae (a1-1) and (a1-3). R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom, a methyl group, or a trifluoromethyl group is more preferable, a hydrogen atom or a methyl group is still more preferable, and a hydrogen atom is particularly preferable.

[0234] In the formula (a10-1), Ya ｘ１ is a single bond or a divalent linking group. ｘ１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ｘ１ The divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in the formula (a00) are described above in detail in the description of L ００ The same applies to the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in the above formula. ｘ１is preferably a single bond, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -O-C(=O)-].

[0235] In the formula (a10-1), Wa ｘ１ is an aromatic hydrocarbon group which may have a substituent. ｘ１ The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ａｘ１ Examples of the aromatic ring include a group in which 4n+1) hydrogen atoms have been removed. The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Wa ｘ１ The aromatic hydrocarbon group in (n) is selected from aromatic compounds containing an aromatic ring which may have two or more substituents (for example, biphenyl, fluorene, etc.). ａｘ１ Also included are groups in which one or more hydrogen atoms have been removed. ｘ１ Examples of the aryl group include benzene, naphthalene, anthracene, and biphenyl (n ａｘ１ A group in which (n +1) hydrogen atoms have been removed is preferred, and a group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ａｘ１ A group in which (n +1) hydrogen atoms have been removed from benzene is more preferred, ａｘ１ A group in which 1) hydrogen atoms have been removed is more preferred.

[0236] Wa ｘ１The aromatic hydrocarbon group in may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl group. The substituent is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, further preferably an ethyl group or a methyl group, and particularly preferably a methyl group. ｘ１ The aromatic hydrocarbon group in the formula (I) preferably does not have a substituent.

[0237] In the formula (a10-1), n ａｘ１ is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0238] Specific examples of the structural unit (a10) represented by the formula (a10-1) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0239]

[0240]

[0241]

[0242] The structural unit (a10) that the component (A1-0) can have may be one type, or two or more types. The component (A1-0) may or may not have the structural unit (a10). When the component (A1-0) has the structural unit (a10), the proportion of the structural unit (a10) within the component (A1-0) is preferably 20 mol % or less, based on the total (100 mol %) of all structural units that make up the component (A1-0). Having the structural unit (a10) in an amount that is no greater than the upper limit of the aforementioned preferred range makes it easier to further enhance sensitivity.

[0243] Regarding the structural unit (a2): The component (A1-0) may further include a structural unit (a2) (excluding those corresponding to the structural unit (a01) and the structural unit (a1)) that includes a lactone-containing cyclic group. When the component (A1-0) is used to form a resist film, the lactone-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate. Furthermore, the presence of the structural unit (a2) provides effects such as appropriate adjustment of the acid diffusion length, improved adhesion of the resist film to the substrate, and appropriate adjustment of the solubility during development, resulting in improved lithography properties.

[0244] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) that contains -O-C(=O)- within its ring skeleton. The lactone ring is counted as the first ring, and when there is only a lactone ring, it is called a monocyclic group, and when there is also another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. There are no particular restrictions on the lactone-containing cyclic group in the structural unit (a2), and any group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0245] [In the formula, Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, or a lactone-containing cyclic group; A″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), an oxygen atom, or a sulfur atom; n′ is an integer of 0 to 2, and m′ is 0 or 1. * represents a bond (the same applies hereinafter).

[0246] In the general formulas (a2-r-1) to (a2-r-7), Ra' ２１The alkyl group in Ra' is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Of these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' ２１ The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, ２１ Examples of the alkyl groups include those mentioned as examples of the alkyl group in the above formula and an oxygen atom (—O—). ２１ The halogen atom in Ra' is preferably a fluorine atom. ２１ As the halogenated alkyl group in the formula Ra′, ２１ Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0247] Ra' ２１In -COOR" and -OC(=O)R" in the formula (I), R" is either a hydrogen atom, an alkyl group, or a lactone-containing cyclic group. The alkyl group for R" may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R" is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably has 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably has 4 to 12 carbon atoms, and most preferably has 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specifically, examples of the lactone-containing cyclic group include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples of the lactone-containing cyclic group for R" include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7). Ra' ２１ The hydroxyalkyl group in the formula (Ra') preferably has 1 to 6 carbon atoms. ２１ and a group in which at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0248] Ra' ２１ Among the above, each of the groups is preferably independently a hydrogen atom or a cyano group.

[0249] In the general formulae (a2-r-2), (a2-r-3), and (a2-r-5), the alkylene group having 1 to 5 carbon atoms for A" is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include groups in which -O- or -S- is present at the terminal or between carbon atoms of the alkylene group, such as -O-CH ２ -, -CH ２ -O-CH ２ -, -S-CH ２ -, -CH ２ -S-CH ２ A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

[0250] Specific examples of the groups represented by general formulae (a2-r-1) to (a2-r-7) are listed below.

[0251]

[0252]

[0253] Of the structural units (a2), structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent are preferred. Such structural units (a2) are preferably structural units represented by the following general formula (a2-1):

[0254] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１ represents a single bond or a divalent linking group. ２１ represents -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. ２１ When is -O-, Ya ２１ does not become -CO-. ２１ is a lactone-containing cyclic group.

[0255] In the formula (a2-1), R is the same as R in the formulas (a1-1) and (a1-3). R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is particularly preferred.

[0256] In the formula (a2-1), Ya ２１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ２１ As the divalent linking group in the formula (a00), ００ The same applies to the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in the above formula. ２１ is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. ２１ is a single bond, and La ２１ is preferably —COO— or —OCO—.

[0257] In the formula (a2-1), Ra ２１ is a lactone-containing cyclic group. ２１ Suitable examples of the lactone-containing cyclic group in the formula (a2-r-1) include the groups represented by the general formulae (a2-r-1) to (a2-r-7) described above.

[0258] The structural unit (a2) that the component (A1-0) can have may be one type, or two or more types. The component (A1-0) may or may not have the structural unit (a2). When the component (A1-0) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 5 to 15 mol %, relative to the total (100 mol %) of all structural units that make up the component (A1-0). When the proportion of the structural unit (a2) is at least the preferred lower limit, the aforementioned effects achieved by including the structural unit (a2) can be fully obtained. When the proportion is at or below the preferred upper limit, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0259] Regarding the structural unit (a8): The structural unit (a8) is a structural unit derived from a compound represented by the following general formula (a8-1).

[0260] [In the formula, W ２ is a polymerizable group-containing group. ｘ２ is a single bond or (n ａｘ２ +1)valent linking group. ｘ２ and W ２ may form a condensed ring. １ is a fluorinated alkyl group having 1 to 12 carbon atoms. ２ R is a hydrogen atom or an organic group having 1 to 12 carbon atoms which may have a fluorine atom. ２ and Ya ｘ２ may be bonded to each other to form a ring structure. ａｘ２ is an integer from 1 to 3.

[0261] W ２ The "polymerizable group" in the polymerizable group-containing group is a group that enables a compound having a polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.

[0262] The polymerizable group-containing group may be a group composed of only a polymerizable group, or may be a group composed of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Examples of the polymerizable group-containing group include a group represented by the chemical formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０ In this chemical formula, R Ｘ１１ , R Ｘ１２ and R Ｘ１３ are each a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Ya ｘ０ is a single bond or a divalent linking group.

[0263] Ya ｘ２ and W ２ The fused ring formed by ２ The polymerizable group at the site and Ya ｘ２ and a fused ring formed by W ２ Other groups than the polymerizable group at the Ya ｘ２ and a fused ring formed by ｘ２ and W ２ The fused ring formed by these may have a substituent.

[0264] Specific examples of the structural unit (a8) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0265]

[0266] The structural unit (a8) that the component (A1-0) can have may be one type, or two or more types. The component (A1-0) may or may not have the structural unit (a8). When the component (A1-0) has the structural unit (a8), the proportion of the structural unit (a8) within the component (A1-0) is preferably 30 mol % or less, more preferably 0 to 20 mol %, and even more preferably 0 to 10 mol %, relative to the total (100 mol %) of all structural units that constitute the component (A1-0).

[0267] In the resist composition of this embodiment, the resin component (component (A1)) whose solubility in a developer changes under the action of acid contains a copolymer (component (A1-0)) having the structural unit (a00), the structural unit (a01), and the structural unit (a02). A preferred example of the component (A1-0) is a copolymer consisting only of repeating units of the structural unit (a00), the structural unit (a01), and the structural unit (a02). With respect to the total (100 mol%) of all structural units constituting the component (A1-0), the proportion of the structural unit (a00) within the component (A1-0) is preferably 5 to 45 mol%, more preferably 10 to 40 mol%, and even more preferably 20 to 35 mol%; the proportion of the structural unit (a01) within the component (A1-0) is preferably 30 to 70 mol%, more preferably 40 to 70 mol%, and even more preferably 50 to 65 mol%; and the proportion of the structural unit (a02) within the component (A1-0) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and even more preferably 5 to 15 mol%, provided that the total proportion of the structural unit (a00), structural unit (a01), and structural unit (a02) does not exceed 100 mol%.

[0268] The component (A1-0) can be produced by dissolving the monomers that derive the respective structural units in a polymerization solvent, adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601), and polymerizing the resulting mixture. ２ -CH ２ -CH ２ -C(CF ３ ) ２ By using a chain transfer agent such as —OH in combination, it is possible to obtain a chain with —C(CF ３ ) ２ A copolymer having a hydroxyalkyl group in which some of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms is thus introduced, and is effective in reducing development defects and LER (line edge roughness: non-uniform irregularities on the line sidewalls).

[0269] The weight-average molecular weight (Mw) of component (A1-0) (based on polystyrene standards measured by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000. When the Mw of component (A1-0) is equal to or less than the preferred upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, while when the Mw is equal to or greater than the preferred lower limit of this range, the component exhibits good dry etching resistance and resist pattern cross-sectional shape. The dispersity (Mw / Mn) of component (A1-0) is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.0 to 2.0. Here, Mn represents the number-average molecular weight.

[0270] The resist composition may contain one type of component (A1-0), or two or more types may be used in combination. The resist composition of this embodiment may also contain, as the component (A1), a resin component (component (A1-1)) that does not fall under the category of the component (A1-0) and whose solubility in a developer changes under the action of acid. The proportion of the component (A1-0) within the component (A1) is preferably 25% by mass or more, more preferably 50% by mass or more, and even more preferably 75% by mass or more, and may even be 100% by mass, relative to the total mass of the component (A1). When this proportion is 25% by mass or more, a resist pattern that exhibits excellent lithography properties, such as high sensitivity, high resolution, reduced roughness, and suppressed film loss, is more likely to be formed.

[0271] Regarding base component (A2): The resist composition of this embodiment may also use, as the component (A), a base component that does not fall under the category of the aforementioned component (A1) (hereafter referred to as "component (A2)"). There are no particular restrictions on the component (A2), and it may be arbitrarily selected from the many base components conventionally known for use in chemically amplified resist compositions. The component (A2) may be a polymeric or low molecular weight compound, and may be used either alone, or in combination of two or more types.

[0272] The amount of the component (A) in the resist composition of this embodiment may be adjusted depending on factors such as the thickness of the resist film to be formed.

[0273] <Other Components> The resist composition of this embodiment may further contain other components in addition to the component (A). Examples of other components include the following components (B), (D), (E), (F), and (S).

[0274] <Component (B): Acid Generator Component> The resist composition of this embodiment may further contain an acid generator component (B) that generates an acid upon exposure. There are no particular limitations on the component (B), and any of the components that have been proposed as acid generators for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl- or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators.

[0275] Examples of the onium salt acid generator include a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), a compound represented by general formula (b-2) (hereinafter also referred to as "component (b-2)"), or a compound represented by general formula (b-3) (hereinafter also referred to as "component (b-3)"):

[0276] [In the formula, R １０１ and R １０４ ~R １０８ R are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. １０４ and R １０５ may be bonded to each other to form a ring structure. １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０１ is a divalent linking group containing an oxygen atom or a single bond. １０１ ~V １０３ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. １０１ and V１０１ cannot be a single bond at the same time. １０１ ~L １０２ are each independently a single bond or an oxygen atom. １０３ ~L １０５ each independently represents a single bond, —CO— or —SO ２ m is an integer of 1 or more, and M' ｍ＋ is an m-valent onium cation.

[0277] {Anion moiety} Anion in component (b-1) In formula (b-1), R １０１ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0278] Cyclic group which may have a substituent: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. Furthermore, the aliphatic hydrocarbon group is preferably saturated.

[0279] R １０１ The aromatic hydrocarbon group in R is a hydrocarbon group having an aromatic ring. The number of carbon atoms in the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. １０１ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. １０１Specific examples of the aromatic hydrocarbon group in include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, benzyl group, phenethyl group, 1-naphthylmethyl group, etc.). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0280] R １０１ Examples of the cyclic aliphatic hydrocarbon group in the formula (I) include aliphatic hydrocarbon groups containing a ring within their structure. Examples of aliphatic hydrocarbon groups containing a ring within their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed within a linear or branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be either a polycyclic group or a monocyclic group. Preferred monocyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a monocycloalkane. Preferred monocycloalkanes have 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. Preferred polycyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkanes include adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ] Polycycloalkanes having a polycyclic skeleton of a bridged ring system, such as decane and tetracyclododecane; and polycycloalkanes having a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton, are more preferred.

[0281] Among them, R １０１The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, further preferably an adamantyl group or a norbornyl group, and particularly preferably an adamantyl group.

[0282] The linear aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ -] and the like. The branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0283] Also, R １０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7), —SO 2 represented by the general formulae (b5-r-1) to (b5-r-4), ２ -containing cyclic groups, and other heterocyclic groups represented by the above chemical formulas (r-hr-1) to (r-hr-16), respectively.

[0284] R １０１Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. The halogen atom as a substituent is preferably a fluorine atom, a bromine atom, or an iodine atom. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH) constituting a cyclic hydrocarbon group. ２ -) is a group that substitutes

[0285] R １０１ The cyclic hydrocarbon group in may be a fused ring group containing a fused ring in which an aliphatic hydrocarbon ring and an aromatic ring are fused. Examples of the fused ring include a polycycloalkane having a bridged ring polycyclic skeleton to which one or more aromatic rings are fused. Specific examples of the bridged ring polycycloalkane include bicycloalkanes such as bicyclo[2.2.1]heptane (norbornane) and bicyclo[2.2.2]octane. The fused ring group is preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicycloalkane, and more preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicyclo[2.2.2]octane. １０１ Specific examples of the fused cyclic group in formula (b-1) include groups represented by the following formulae (r-br-1) and (r-br-2). １０１ represents a bond bonded to

[0286]

[0287] R １０１Examples of the substituent that the fused cyclic group in the formula (I) may have include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an aromatic hydrocarbon group, an alicyclic hydrocarbon group, etc. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group can be selected from the group consisting of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group described above in R １０１ Examples of the aromatic hydrocarbon group as a substituent of the fused cyclic group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.), and heterocyclic groups represented by the above formulas (r-hr-1) to (r-hr-6). Examples of the alicyclic hydrocarbon group as a substituent of the fused cyclic group include a group in which one hydrogen atom has been removed from a monocycloalkane such as cyclopentane or cyclohexane; adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ a group in which one hydrogen atom has been removed from a polycycloalkane such as decane or tetracyclododecane; a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7); a —SO 2 group represented by each of the general formulae (b5-r-1) to (b5-r-4), ２ -containing cyclic group: heterocyclic groups represented by the above formulae (r-hr-7) to (r-hr-16), respectively.

[0288] A chain alkyl group which may have a substituent: R １０１The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0289] A chain alkenyl group which may have a substituent: R １０１ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the above chain alkenyl groups, a linear alkenyl group is preferred, a vinyl group or a propenyl group is more preferred, and a vinyl group is particularly preferred.

[0290] R １０１ Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the R １０１ Examples of the cyclic groups include the cyclic groups shown in the formula:

[0291] In formula (b-1), Y １０１ is a single bond or a divalent linking group containing an oxygen atom. １０１ is a divalent linking group containing an oxygen atom, １０１may contain an atom other than an oxygen atom. Examples of atoms other than an oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom. Examples of the divalent linking group containing an oxygen atom include linking groups represented by the following general formulas (y-a1-1) to (y-a1-7). In the following general formulas (y-a1-1) to (y-a1-7), R in the above formula (b-1) １０１ The bond to V' in the following general formulae (y-al-1) to (y-al-7) is １０１ is.

[0292] [In the formula, V' １０１ is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' １０２ is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0293] V' １０２ The divalent saturated hydrocarbon group in is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 5 carbon atoms.

[0294] V' １０１ and V' １０２ The alkylene group in V' may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group. １０１ and V' １０２ Specific examples of the alkylene group in ２ -]; -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; ethylene groups [-CH ２CH ２ -]; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, etc.; a trimethylene group (n-propylene group) [—CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ an alkyltrimethylene group such as -; a tetramethylene group [-CH ２ CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, etc.; an alkyltetramethylene group such as a pentamethylene group [—CH ２ CH ２ CH ２ CH ２ CH ２ -]. Also, V' １０１ or V' １０２ In the formula (a1-r-1), some of the methylene groups in the alkylene group may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is represented by Ra' in the formula (a1-r-1). ３ A divalent group obtained by removing one more hydrogen atom from a cyclic aliphatic hydrocarbon group (a monocyclic aliphatic hydrocarbon group or a polycyclic aliphatic hydrocarbon group) of the above formula (I) is preferred, and a cyclohexylene group, a 1,5-adamantylene group, or a 2,6-adamantylene group is more preferred.

[0295] In formula (b-1), V １０１is a single bond, an alkylene group or a fluorinated alkylene group. １０１ is preferably a single bond or a linear fluorinated alkylene group having 1 to 4 carbon atoms.

[0296] In formula (b-1), R １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０２ is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

[0297] Specific examples of the anion moiety represented by the formula (b-1) include, for example, Y １０１ When Y is a single bond, examples of the anion include a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion or a perfluorobutanesulfonate anion; １０１ When is a divalent linking group containing an oxygen atom, examples of the anion include anions represented by any one of the following formulae (an-1) to (an-3).

[0298] [In the formula, R” １０１ R" is an aliphatic cyclic group which may have a substituent, a monovalent heterocyclic group represented by each of the above chemical formulas (r-hr-1) to (r-hr-16), a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), a chain alkyl group which may have a substituent, or an aromatic cyclic group which may have a substituent. １０２ represents an aliphatic cyclic group which may have a substituent, a fused cyclic group represented by the formula (r-br-1) or (r-br-2) above, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1), (a2-r-3) to (a2-r-7) above, or —SO ２ -containing cyclic group. １０３ V" is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. １０１ is a single bond, an alkylene group having 1 to 4 carbon atoms, or a fluorinated alkylene group having 1 to 4 carbon atoms. １０２is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms; each v" is independently an integer of 0 to 3; each q" is independently an integer of 0 to 20; and n" is 0 or 1.

[0299] R” １０１ , R” １０２ and R” １０３ The aliphatic cyclic group which may have a substituent is represented by R １０１ The substituent is preferably a group exemplified as the cyclic aliphatic hydrocarbon group in the formula (b-1). １０１ Examples of the substituents that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1) include the same as those that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1).

[0300] R” １０１ and R” １０３ The aromatic cyclic group which may have a substituent in the formula (b-1) is R １０１ The substituent is preferably a group exemplified as an aromatic hydrocarbon group in the cyclic hydrocarbon group in the formula (b-1). １０１ Examples of the substituents that may substitute the aromatic hydrocarbon group in the above formula (1) include the same as those in the above formula (1).

[0301] R” １０１ The chain alkyl group which may have a substituent in the formula (b-1) is R １０１ R" is preferably a group exemplified as a chain alkyl group in １０３ The chain alkenyl group which may have a substituent is R １０１ Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0302] Anion in component (b-2) In formula (b-2), R １０４ , R １０５ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R １０１ However, R １０４ , R １０５may be bonded to each other to form a ring. １０４ , R １０５ is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. The number of carbon atoms in the chain alkyl group is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 3. １０４ , R １０５ The number of carbon atoms in the chain alkyl group of R is preferably as small as possible within the above range of carbon atoms, for reasons such as good solubility in resist solvents. １０４ , R １０５ In the chain alkyl group, the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength and the improved transparency to high-energy light of 250 nm or less and electron beams, which is preferable. The proportion of fluorine atoms in the chain alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms. In formula (b-2), V １０２ , V １０３ are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and each represents V in formula (b-1). １０１ In formula (b-2), L １０１ , L １０２ are each independently a single bond or an oxygen atom.

[0303] Anion in component (b-3) In formula (b-3), R １０６ ~R １０８ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R １０１ In formula (b-3), L １０３ ~L １０５ each independently represents a single bond, —CO— or —SO ２ - is.

[0304] Of the above, the anion moiety of component (B) is preferably the anion in component (b-1), and more preferably the anion represented by formula (an-1).

[0305] {Cation Moiety} In the formula (b-1), formula (b-2), and formula (b-3), M' ｍ＋ represents an m-valent onium cation. Among these, sulfonium cation and iodonium cation are preferred. m is an integer of 1 or more.

[0306] The cation moiety of the component (B) is preferably a sulfonium cation, more preferably a cation represented by each of the formulas (ca-1) to (ca-3), still more preferably a cation represented by the formula (ca-1), and particularly preferably a cation represented by each of the formulas (ca-1-1) to (ca-1-87).

[0307] In the resist composition of this embodiment, the component (B) may be used singly, or two or more types may be used in combination. When the resist composition contains the component (B), the amount of the component (B) in the resist composition, relative to 100 parts by mass of the component (A1-0), is preferably less than 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 40 parts by mass. By ensuring that the amount of the component (B) falls within the above-mentioned preferred range, a homogeneous solution is more likely to be obtained when the respective components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition is favorable.

[0308] <Component (D): Base Component> In addition to the component (A), the resist composition of this embodiment may contain a base component (component (D)) that traps acid generated upon exposure (i.e., controls the diffusion of acid). The component (D) acts as a quencher (acid diffusion controller) that traps acid generated in the resist composition upon exposure. Examples of the component (D) include a photodegradable base (D1) (hereinafter referred to as “component (D1)”) that decomposes upon exposure and loses its ability to control acid diffusion, and a nitrogen-containing organic compound (D2) (hereinafter referred to as “component (D2)”) that does not fall under the category of component (D1). Among these, the photodegradable base (component (D1)) is preferred because it is likely to enhance all of the properties of high sensitivity, reduced roughness, and suppressed coating defects. The compounds exemplified below as component (D1) may be used as the acid generator component (component (B)) described above, depending on the combination with other compounds.

[0309] Regarding the component (D1): The component (D1) is not particularly limited as long as it decomposes upon exposure and loses its acid diffusion controllability, and is preferably one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)"). The components (d1-1) to (d1-3) decompose and lose their acid diffusion controllability (basicity) in the exposed areas of the resist film, and therefore do not act as quenchers, but act as quenchers in the unexposed areas of the resist film.

[0310] [In the formula, Rd １ ~Rd ４ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the above, no fluorine atom is bonded to the carbon atom adjacent to the S atom. １ is a single bond or a divalent linking group; m is an integer of 1 or more; M ｍ＋are each independently an m-valent onium cation.

[0311] {Component (d1-1)} Anion portion In formula (d1-1), Rd １ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of the R' ２０１ Among these, Rd １ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5). Note that Rd １ In the above general formulas (y-al-1) to (y-al-7), when the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group has, as a substituent, a linking group represented by each of the general formulae (y-al-1) to (y-al-7), Rd in formula (d1-1) １ The carbon atom constituting the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group in the formula (y-al-1) to (y-al-7) is bonded to V' １０１ Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (a polycyclic structure consisting of a bicyclooctane skeleton and another ring structure). Suitable examples of the aliphatic cyclic group include adamantane, norbornane, isobornane, tricyclo[5.2.1.0], ２，６

[0033] More preferably, it is a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as decane or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; and branched alkyl groups such as 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, and 4-methylpentyl groups.

[0312] When the chain-like alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the number of carbon atoms in the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8, and even more preferably 1 to 4. The fluorinated alkyl group may contain an atom other than a fluorine atom. Examples of the atom other than a fluorine atom include an oxygen atom, a sulfur atom, and a nitrogen atom.

[0313] Specific examples of preferred anion moieties of component (d1-1) are shown below.

[0314]

[0315] ...cation moiety In formula (d1-1), M ｍ＋ is an m-valent onium cation. ｍ＋ Suitable onium cations include those similar to those represented by the general formulae (ca-1) to (ca-3), with the cation represented by the general formula (ca-1) being more preferred, and the cations represented by the general formulae (ca-1-1) to (ca-1-87) being even more preferred. One type of component (d1-1) may be used alone, or two or more types may be used in combination.

[0316] {Component (d1-2)} Anion portion In formula (d1-2), Rd ２is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ However, Rd ２ In the formula, the carbon atom adjacent to the S atom is not bonded to a fluorine atom (is not substituted with fluorine). This makes the anion of component (d1-2) an appropriately weak acid anion, improving the quenching ability of component (D). ２ The alkyl group is preferably a chain alkyl group which may have a substituent or an aliphatic cyclic group which may have a substituent, and more preferably an aliphatic cyclic group which may have a substituent.

[0317] The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10. The aliphatic cyclic group includes adamantane, norbornane, isobornane, tricyclo[5.2.1.0], ２，６ ] a group (which may have a substituent) in which one or more hydrogen atoms have been removed from decane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor is more preferred.

[0318] Rd ２ The hydrocarbon group may have a substituent, and the substituent may be Rd １ Examples of the substituents include the same as those that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above.

[0319] Specific examples of preferred anion moieties of component (d1-2) are shown below.

[0320]

[0321] In formula (d1-2), M ｍ＋ is an m-valent onium cation, and M in the formula (d1-1) ｍ＋ The component (d1-2) may be used alone or in combination of two or more.

[0322] {Component (d1-3)} Anion portion In formula (d1-3), Rd３ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, a fluorinated alkyl group is preferred, and the Rd １ The same fluorinated alkyl groups as those mentioned above are more preferred.

[0323] In formula (d1-3), Rd ４ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, an alkyl group, an alkoxy group, an alkenyl group, or a cyclic group which may have a substituent is preferable. ４ The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. ４ A part of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, etc. ４ The alkoxy group in is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

[0324] Rd ４ The alkenyl group in R' ２０１ Examples include the same alkenyl groups as those in the above, and vinyl, propenyl (allyl), 1-methylpropenyl, and 2-methylpropenyl groups are preferred. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

[0325] Rd ４ The cyclic group in the formula (I) is the same as the R'２０１ Examples thereof include cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclo[5.2.1.0], and the like. ２，６ ] An alicyclic group in which one or more hydrogen atoms have been removed from a cycloalkane such as decane or tetracyclododecane, or an aromatic group such as a phenyl group or naphthyl group is preferred. ４ When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, resulting in excellent lithography properties. ４ When is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition exhibits excellent light absorption efficiency, and exhibits favorable sensitivity and lithography properties.

[0326] In formula (d1-3), Yd １ represents a single bond or a divalent linking group. １ The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. ２１ Examples of the divalent linking group include the same divalent hydrocarbon group which may have a substituent and the same divalent linking group containing a hetero atom as those mentioned in the description of the divalent linking group in １ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0327] Specific examples of preferred anion moieties of component (d1-3) are shown below.

[0328]

[0329]

[0330] In formula (d1-3), M ｍ＋ is an m-valent onium cation, and M in the formula (d1-1) ｍ＋The component (d1-3) may be used alone or in combination of two or more.

[0331] The component (D1) may be any one of the above components (d1-1) to (d1-3), or a combination of two or more of them. When the resist composition contains the component (D1), the amount of the component (D1) within the resist composition is preferably 0.5 to 15 parts by mass, more preferably 1 to 12 parts by mass, and even more preferably 2 to 10 parts by mass, relative to 100 parts by mass of the component (A1-0).

[0332] The component (D1) preferably contains the component (d1-1). The content of the component (d1-1) in the entire component (D1) is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more. The component (D1) may consist solely of the compound component (d1-1).

[0333] Production method of component (D1): The production methods of the components (d1-1) and (d1-2) are not particularly limited, and they can be produced by known methods. The production method of component (d1-3) is also not particularly limited, and it can be produced, for example, by the method described in US 2012-0149916.

[0334] Regarding the (D2) component: The (D) component may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the above-mentioned (D1) component. The (D2) component is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of the (D1) component, and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are more preferred. The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms. Examples of the aliphatic amine include ammonia NH ３Examples of the amine include amines in which at least one hydrogen atom is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 6 to 30 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0335] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of aliphatic monocyclic amines include piperidine and piperazine. Specific examples of aliphatic polycyclic amines include those having 6 to 10 carbon atoms, such as 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0336] Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, triethanolamine triacetate, and the like, with triethanolamine triacetate being preferred.

[0337] Furthermore, the component (D2) may be an aromatic amine, such as 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole, or a derivative thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, or 2,6-di-tert-butylpyridine.

[0338] The component (D2) may be used singly, or in combination of two or more types. When the resist composition contains the component (D2), the amount of the component (D2) within the resist composition is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A1-0). By ensuring that the amount is within this range, the resist pattern shape and stability over time during storage can be improved.

[0339] <Component (E): At least one compound selected from the group consisting of organic carboxylic acids, and phosphorus oxoacids and their derivatives> The resist composition of this embodiment may contain at least one compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, and phosphorus oxoacids and their derivatives as an optional component for the purposes of preventing sensitivity degradation and improving resist pattern shape and post-exposure stability. Specific examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid, with salicylic acid being preferred. Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred.

[0340] In the resist composition of this embodiment, the component (E) may be used singly, or two or more different components may be used in combination. When the resist composition contains the component (E), the amount of the component (E) per 100 parts by mass of the component (A1-0) is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass. By ensuring that the amount is within this range, lithography properties are further improved.

[0341] <Component (F): Fluorine Additive Component> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as "component (F)") as a hydrophobic resin. The component (F) is used to impart water repellency to the resist film, and by using it as a resin separate from component (A), it is possible to improve lithography properties. Examples of component (F) that can be used include the fluorine-containing polymer compounds described in JP 2010-002870 A, JP 2010-032994 A, JP 2010-277043 A, JP 2011-13569 A, and JP 2011-128226 A. More specific examples of component (F) include polymers having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting only of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a01); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a01), with the structural unit (f1) being more preferred. Here, the structural unit (a01) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate, with a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate being more preferred.

[0342] [wherein R is the same as defined above, and Rf １０２ and Rf １０３Rf each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; １０２ and Rf １０３ may be the same or different, nf1 is an integer of 0 to 5, and Rf １０１ is an organic group containing a fluorine atom.

[0343] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. １０２ and Rf １０３ The halogen atom in Rf is preferably a fluorine atom. １０２ and Rf １０３ Examples of the alkyl group having 1 to 5 carbon atoms in Rf include the same alkyl groups having 1 to 5 carbon atoms as those in R, and a methyl group or an ethyl group is preferred. １０２ and Rf １０３ Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is preferred. Among these, Rf １０２ and Rf １０３ In formula (f1-1), nf1 is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0344] In formula (f1-1), Rf １０１is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The hydrocarbon group containing a fluorine atom may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. In addition, the hydrocarbon group containing a fluorine atom is preferably one in which 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among these, Rf １０１ is preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, more preferably a trifluoromethyl group, —CH ２ -CF ３ , -CH ２ -CF ２ -CF ３ , -CH(CF ３ ) ２ , -CH ２ -CH ２ -CF ３ , -CH ２ -CH ２ -CF ２ -CF ２ -CF ２ -CF ３ is particularly preferred.

[0345] The weight-average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. When the Mw is below the upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, while when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

[0346] In the resist composition of this embodiment, the component (F) may be used either as a single type, or as a combination of two or more types. When the resist composition contains the component (F), the amount of the component (F) relative to 100 parts by mass of the component (A1-0) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass.

[0347] <Component (S): Organic Solvent Component> The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as "component (S)"). The component (S) can be any solvent that is capable of dissolving the various components used and forming a homogeneous solution, and any solvent can be appropriately selected from among those conventionally known as solvents for chemically amplified resist compositions. In the resist composition of this embodiment, the component (S) can be used alone, or as a mixed solvent of two or more different solvents. Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), γ-butyrolactone, ethyl lactate (EL), and cyclohexanone are preferred.

[0348] Also preferred as the (S) component is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into consideration the compatibility of PGMEA with the polar solvent, etc. Also preferred as the (S) component is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone. In this case, the mass ratio of the former to the latter is preferably 70:30 to 95:5. The amount of the (S) component is not particularly limited and is appropriately set according to the coating film thickness at a concentration that allows application to a substrate, etc. The (S) component is generally used so that the solids concentration of the resist composition is within the range of 0.1 to 20 mass%, preferably 0.2 to 15 mass%.

[0349] The resist composition of this embodiment may further contain, if desired, compatible additives such as an additional resin for improving the performance of the resist film, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, or a dye.

[0350] In the resist composition of this embodiment, after dissolving the resist material in component (S), impurities may be removed using a polyimide porous film, a polyamideimide porous film, or the like. For example, the resist composition may be filtered using a filter made of a polyimide porous film, a filter made of a polyamideimide porous film, or a filter made of a polyimide porous film and a polyamideimide porous film. Examples of the polyimide porous film and the polyamideimide porous film include those described in JP 2016-155121 A.

[0351] As explained above, the resist composition of this embodiment contains, as a base component, a copolymer having a structural unit represented by general formula (a00) (structural unit (a00)), a structural unit represented by general formula (a01) (structural unit (a01)), and a structural unit represented by general formula (a02) that generates acid upon exposure (structural unit (a02)). The structural unit (a00) has a maleimide structure as a polymerizable group that is highly soluble in a developer, and also functions as a proton source. By incorporating the structural unit (a02), which generates acid upon exposure, into the resin that is the base component, acid is more easily generated uniformly within the resist film, and the content of low-molecular-weight components (for example, component (B)) can be reduced, thereby suppressing dissolution of unexposed areas of the resist film. Furthermore, the resin that is the base component may contain an acid-dissociable group (R Ｘ Since the structural unit (a01) containing the structural unit (a02) is bonded to the structural unit (a01), a reaction tends to proceed uniformly throughout the entire resist film. In addition, since the structural unit (a00) having a highly rigid maleimide structure and the structural unit (a02) that generates acid upon exposure are bonded to the resin that is the base component, the diffusion of the acid generated upon exposure is easily controlled. Due to these synergistic effects, the resist composition of this embodiment achieves high sensitivity in resist pattern formation, and enhances the effects of both reducing roughness and suppressing film loss.

[0352] (Method of forming a resist pattern) A method of forming a resist pattern according to a second aspect of the present invention is a method comprising the steps of forming a resist film on a support using the resist composition according to the first aspect of the present invention, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. One embodiment of this method of forming a resist pattern is a method of forming a resist pattern carried out as follows.

[0353] First, the resist composition of the above-described embodiment is applied to a support using a spinner or the like, and baked (post-applied bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an ArF lithography device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without a mask pattern. The resist film is then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed. In the case of an alkali development process, the development is performed using an alkaline developer, and in the case of a solvent development process, a developer containing an organic solvent (organic developer) is used.

[0354] After the development treatment, a rinse treatment is preferably carried out. In the case of an alkaline development process, the rinse treatment is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse solution containing an organic solvent is preferably used. In the case of a solvent development process, after the development treatment or rinse treatment, a treatment may be carried out to remove the developer or rinse solution adhering to the pattern using a supercritical fluid. After the development treatment or rinse treatment, drying is carried out. Furthermore, in some cases, a bake treatment (post-bake) may be carried out after the development treatment.

[0355] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those on which a predetermined wiring pattern is formed. More specifically, examples include silicon wafers, substrates made of metals such as copper, chromium, iron, and aluminum, and glass substrates. Materials that can be used for the wiring pattern include copper, aluminum, nickel, and gold.

[0356] The wavelength used for exposure is not particularly limited, and may be an ArF excimer laser, a KrF excimer laser, or a F ２ Radiation such as excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. The method of forming a resist pattern of this embodiment is particularly useful for a method in which the resist film is exposed to EUV (extreme ultraviolet) or EB (electron beam) in the step of exposing the resist film.

[0357] The exposure method for the resist film may be a normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be liquid immersion exposure (liquid immersion lithography). Liquid immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure apparatus is filled in advance with a solvent (immersion medium) having a refractive index greater than that of air, and exposure (immersion exposure) is performed in this state. The liquid immersion medium is preferably a solvent having a refractive index greater than that of air and smaller than that of the resist film to be exposed, and examples thereof include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent. Water is preferably used as the liquid immersion medium.

[0358] An example of an alkaline developer used in the development treatment in the alkaline development process is a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent that can dissolve component (A) (component (A) before exposure), and can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents.

[0359] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

[0360] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0361] The organic developer may contain known additives as needed. Examples of such additives include surfactants. The surfactants are not particularly limited, but may include, for example, ionic or nonionic fluorine-based and / or silicon-based surfactants.

[0362] The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the surface of the support by surface tension and leaving it standing for a certain period of time (puddle method), a method of spraying the developer onto the surface of the support (spray method), or a method of continuously applying the developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0363] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be appropriately selected from the organic solvents listed above as organic solvents used in the organic developer, as long as they do not easily dissolve the resist pattern. Typically, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. These organic solvents may be used alone or in combination with two or more. They may also be used in combination with other organic solvents or water.

[0364] The rinse treatment (cleaning treatment) using a rinse solution can be carried out by a known rinse method, such as a method of continuously applying the rinse solution onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse solution for a certain period of time (dipping method), or a method of spraying the rinse solution onto the surface of the support (spray method).

[0365] As described above, according to the method of forming a resist pattern of this embodiment, the resist composition described above is used, thereby achieving high sensitivity in resist pattern formation, and being highly effective in reducing roughness and suppressing film loss, making it possible to form a resist pattern with a favorable shape.

[0366] The resist composition of the above-described embodiment and the various materials used in the resist pattern formation method of the above-described embodiment (e.g., resist solvent, developer, rinse, anti-reflective coating-forming composition, top coat-forming composition, etc.) preferably do not contain impurities such as metals, halogen-containing metal salts, acids, alkalis, or components containing sulfur atoms or phosphorus atoms. Examples of impurities containing metal atoms include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, and salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially free of impurities (below the detection limit of the measuring device).

[0367] (Copolymer) A third aspect of the present invention is a copolymer having a structural unit represented by the following general formula (a00), a structural unit represented by the following general formula (a01), and a structural unit represented by the following general formula (a02) that generates acid upon exposure.

[0368] [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒ is an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group. ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom.０２ is a divalent linking group. － is an anionic group. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0369] The structural unit represented by general formula (a00) is the same as the structural unit (a00) described above in the resist composition. Ａｒ is preferably an aromatic group having an iodine atom as a substituent. Preferred examples of the structural unit (a00) include structural units represented by the above general formula (a00-u).

[0370] The structural unit represented by general formula (a01) is the same as the structural unit (a01) described above in the resist composition. Ｘ is preferably an acid-dissociable group that is bonded to the oxygen atom (-O-) in -C(=O)-O- in formula (a01) via a carbon atom and has a carbon-carbon unsaturated bond formed between the α-position of the carbon atom and the β-position of the carbon atom. Preferred examples of the structural unit (a01) include structural units represented by general formula (a1-1) or (a1-3) above.

[0371] The structural unit represented by general formula (a02) that generates acid upon exposure is the same as the structural unit (a02) described above in the resist composition. ｍ＋ is preferably an m-valent onium cation having a fluorine atom. － is preferably a sulfonate ion. Preferred examples of the structural unit (a02) include structural units represented by general formula (a02-u) shown above.

[0372] The copolymer related to the third aspect is the same as the copolymer (component (A1-0)) described above in the (resist composition) section. A preferred example of the component (A1-0) is a copolymer consisting only of repeating structures of the structural unit (a00), the structural unit (a01), and the structural unit (a02). Based on the total (100 mol%) of all structural units constituting the component (A1-0), the proportion of the structural unit (a00) within the component (A1-0) is preferably 5 to 45 mol%, more preferably 10 to 40 mol%, and even more preferably 20 to 35 mol%; the proportion of the structural unit (a01) within the component (A1-0) is preferably 30 to 70 mol%, more preferably 40 to 70 mol%, and even more preferably 50 to 65 mol%; and the proportion of the structural unit (a02) within the component (A1-0) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and even more preferably 5 to 15 mol%. However, the total amount of the structural units (a00), (a01), and (a02) does not exceed 100 mol %.

[0373] The weight average molecular weight (Mw) (based on polystyrene equivalent by gel permeation chromatography (GPC)) of the copolymer related to the third aspect (component (A1-0)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000. The dispersity (Mw / Mn) of component (A1-0) is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.0 to 2.0.

[0374] The copolymer related to the third aspect, that is, the component (A1-0), is a resin component that is suitable as the base component of the resist composition related to the first aspect.

[0375] (Compound) A fourth aspect of the present invention is a compound represented by the following general formula (a00-M1) or general formula (a00-M2).

[0376] [In formula (a00-M1) and formula (a00-M2), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom.００ is a divalent linking group or a single bond. ０ｃ is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group, and p is an integer of 1 to 4.

[0377] In the above formula (a00-M1) and formula (a00-M2), R ０ａ and R ０ｂ , L ００ represents R in the above general formula (a00). ０ａ and R ０ｂ , L ００ The explanations are the same as those for R. ０ａ and R ０ｂ are each preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability, and even more preferably a hydrogen atom, and R ０ａ and R ０ｂ It is particularly preferred that all of L are hydrogen atoms. ００ is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. ００ is preferably a single bond.

[0378] In the above formula (a00-M1) and formula (a00-M2), R ０ｃ represents R in the above general formula (a00-u). ０ｃ The explanation is the same as for R. ０ｃ From the viewpoint of use in a resist composition, p is preferably at least one selected from the group consisting of a halogen atom and an alkyl group, more preferably a halogen atom, and among these, from the viewpoint of the effects of sensitivity, reduction in roughness, and suppression of film loss, even more preferably an iodine atom. p is preferably 1 or 2, more preferably 1.

[0379] Specific examples of the compound represented by general formula (a00-M1) and the compound represented by general formula (a00-M2) are shown below. ００ａ and R ００ｂeach independently represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0380]

[0381]

[0382] [Method for Producing Compound] As shown in the synthesis examples below, the compound according to the fourth aspect can be produced by, for example, combining maleic anhydride and a specific substituent (R ０ｃ ) and an aminophenol in which an amino group is substituted at a predetermined position, in the presence of an acid catalyst.

[0383] As described above, the compound of this embodiment has a hydroxy group bonded to the meta position or the ortho position and a specific substituent (R ０ｃ ) and can be used as a raw material monomer for the copolymer according to the third aspect. When a copolymer using the compound according to the fourth aspect is used as a base component in a resist composition, it is effective in suppressing film loss in unexposed areas of the resist film.

[0384] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In these examples, the compound represented by chemical formula (1) will be referred to as "compound (1)," and the same will be used for compounds represented by other chemical formulas.

[0385] <Synthesis Examples of Compounds> [Synthesis Example 1: Synthesis of Compound (a00-M1-1)] Maleic anhydride (10.8 g), 3-aminophenol (10.9 g), dimethylformamide (DMF) (30.0 g), and toluene (120.0 g) were charged and stirred for 1 hour. After adding p-toluenesulfonic acid (1.4 g) dissolved in DMF (10.0 g), the mixture was heated to 160°C in an oil bath and stirred for 5 hours. After cooling to room temperature, ultrapure water (500.0 g) was charged and stirred for 30 minutes. After stopping the stirring, the aqueous layer was removed and the mixture was further washed with a 5 wt% aqueous sodium carbonate solution (500.0 g). The aqueous layer was removed and the mixture was further washed with ultrapure water (500.0 g). The organic layer was concentrated under reduced pressure, and the concentrated residue was crystallized from acetonitrile / tert-butyl methyl ether to obtain 9.9 g of compound (a00-M1-1).

[0386]

[0387] The resulting compound (a00-M1-1) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6,400MHz) δ (ppm) = 9.59 (s, 1H), 7.86 (d, 2H), 7.25 (t, 1H), 6.80 (d, 1H), 6.79 (s, 1H), 6.77 (d, 1H)

[0388] Synthesis Example 2 Synthesis of Compound (a00-M2-1) Compound (a00-M2-1) was synthesized in the same manner as in Synthesis Example 1, except that 2-aminophenol was used instead of 3-aminophenol.

[0389]

[0390] The resulting compound (a00-M2-1) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6,400MHz) δ (ppm) = 9.85 (s, 1H), 7.86 (d, 2H), 7.31 (t, 1H), 7.16 (d, 1H), 6.99 (d, 1H), 6.92 (t, 1H)

[0391] Synthesis Example 3 Synthesis of Compound (a00-M1-2) Compound (a00-M1-2) was synthesized in the same manner as in Synthesis Example 1, except that 2-iodo-5-aminophenol was used instead of 3-aminophenol.

[0392]

[0393] The resulting compound (a00-M1-2) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6,400MHz) δ (ppm) = 11.59 (s, 1H), 7.86 (d, 2H), 7.70 (d, 1H), 6.98 (s, 1H), 6.91 (d, 1H)

[0394] Synthesis Example 4 Synthesis of Compound (a00-M1-3) Compound (a00-M1-3) was synthesized in the same manner as in Synthesis Example 1, except that 2-fluoro-5-aminophenol was used instead of 3-aminophenol.

[0395]

[0396] The resulting compound (a00-M1-3) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6,400MHz) δ (ppm) = 9.00 (s, 1H), 7.86 (d, 2H), 7.13 (d, 1H), 7.12 (s, 1H), 7.12 (d, 1H)

[0397] Synthesis Example 5 Synthesis of Compound (a00-M2-2) Compound (a00-M2-2) was synthesized in the same manner as in Synthesis Example 1, except that 6-amino-m-cresol was used instead of 3-aminophenol.

[0398]

[0399] The resulting compound (a00-M2-2) was subjected to NMR measurement, and its structure was identified from the following analytical results. １H-NMR (DMSO-d6,400MHz) δ (ppm) = 10.06 (s, 1H), 7.86 (d, 2H), 7.43 (d, 1H), 6.85 (d, 1H), 6.80 (s, 1H), 2.28 (s, 3H)

[0400] Synthesis Example 6 Synthesis of Compound (a00-M2-3) Compound (a00-M2-3) was synthesized in the same manner as in Synthesis Example 1, except that 2-amino-4-iodophenol was used instead of 3-aminophenol.

[0401]

[0402] The resulting compound (a00-M2-3) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6,400MHz) δ (ppm) = 9.89 (s, 1H), 7.86 (d, 2H), 7.72 (d, 1H), 7.44 (s, 1H), 6.68 (d, 1H)

[0403] Synthesis Example 7 Synthesis of Compound (a02-M-1) 3,5-Diiodosalicylic acid (40.0 g) and tetrahydrofuran (THF) (160.0 g) were charged and stirred to dissolve. 1,1'-carbonyldiimidazole (CDI) (20.0 g) was added thereto, and the mixture was heated to 60°C in a water bath and stirred for 1 hour. Compound (1a) (38.3 g) was added thereto, and the mixture was aged for 1 hour. Then, ultrapure water (160.0 g) and dichloromethane (160.0 g) were charged and stirred. After stirring was stopped, the aqueous layer was removed and further washed with ultrapure water (160 g). The organic layer was concentrated under reduced pressure, and the concentrated residue was crystallized from acetonitrile / tert-butyl methyl ether to obtain 43.2 g of a white intermediate (Pre-P1a).

[0404]

[0405] 4-Vinylbenzoic acid (9.6 g), intermediate (Pre-P1a) (40.0 g), 4-dimethylaminopyridine (DMAP) (0.7 g), and dichloromethane (400.0 g) were stirred at 0°C. To this was added 1,3-diisopropylcarbodiimide (DIC) (8.9). After stirring at room temperature for 3 hours, the mixture was concentrated under reduced pressure. The concentrated residue was crystallized from acetonitrile / tert-butyl methyl ether to obtain 31.5 g of a white intermediate (Pre-P1b).

[0406]

[0407] Intermediate (Pre-P1b) (30.0 g), compound (1b) (21.3 g), dichloromethane (150.0 g), and ultrapure water (60.0 g) were stirred at room temperature and separated into layers. The organic layer was washed five times with ultrapure water (60.0 g) and then concentrated under reduced pressure to obtain 30.5 g of compound (a02-M-1).

[0408]

[0409] The resulting compound (a02-M-1) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6, 400MHz) δ (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 17H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H)

[0410] Synthesis Example 8 Synthesis of Compound (a02-M-2) Compound (a02-M-2) was synthesized in the same manner as in Synthesis Example 7, except that compound (2b) was used instead of compound (1b).

[0411]

[0412] The obtained compound (a02-M-2) was subjected to NMR measurement, and its structure was identified from the following analytical results. １H-NMR (DMSO-d6, 400MHz) δ (ppm) = 8.58 (m, 3H), 8.31 (m, 3H), 8.13 (d, 2H), 8. 00-7.72 (m, 11H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H)

[0413] Synthesis Example 9 Synthesis of Compound (a02-M-3) Compound (a02-M-3) was synthesized in the same manner as in Synthesis Example 7, except that compound (3b) was used instead of compound (1b).

[0414]

[0415] The obtained compound (a02-M-3) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6, 400MHz) δ (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 14H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H)

[0416] Synthesis Example 10 Synthesis of Compound (a02-M-4) Compound (a02-M-4) was synthesized in the same manner as in Synthesis Example 7, except that compound (4b) was used instead of compound (1b).

[0417]

[0418] The obtained compound (a02-M-4) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6, 400MHz) δ (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 13H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H)

[0419] Synthesis Example 11 Synthesis of Compound (a02-M-5) Compound (a02-M-5) was synthesized in the same manner as in Synthesis Example 7, except that compound (5b) was used instead of compound (1b).

[0420]

[0421] The obtained compound (a02-M-5) was subjected to NMR measurement, and its structure was identified from the following analytical results. １ H-NMR (DMSO-d6, 400MHz) δ (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 11H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H)

[0422] <Synthesis Example of Copolymer> [Synthesis of Copolymer (A1-0-1)] 6.0 g of compound (a00-M3-1), 10.0 g of compound (a01-M-1), 2.9 g of compound (a02-M-1), and 2.0 g of azobis(isobutyrate) dimethyl (V-601) as a polymerization initiator were dissolved in 55 g of MEK (methyl ethyl ketone), heated to 80 ° C. under a nitrogen atmosphere, and stirred for 6 hours. After completion of the reaction, the resulting reaction solution was precipitated in 600 g of heptane and washed. The resulting white solid was filtered and dried under reduced pressure overnight to obtain 13.0 g of the target copolymer (A1-0-1).

[0423]

[0424] [Synthesis of Copolymers (A1-0-2) to (A1-0-18)] Copolymers (A1-0-2) to (A1-0-18) were synthesized in the same manner as in the above-mentioned [Synthesis of Copolymer (A1-0-1)], except that the monomers used and the amounts used were changed.

[0425] The raw material monomers corresponding to each copolymer and the structures of the resulting copolymers (A1-0-1) to (A1-0-18) are shown below, where l, m, and n represent the compositional ratio of each structural unit.

[0426]

[0427]

[0428]

[0429]

[0430]

[0431]

[0432]

[0433]

[0434] The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) of each of the copolymers (A1-0-1) to (A1-0-18) were determined by GPC measurement (standard polystyrene equivalent). Furthermore, the copolymer composition ratios (proportions (molar ratios) of each structural unit in the structural formula) of each of the copolymers (A1-0-1) to (A1-0-18) were determined by carbon-13 nuclear magnetic resonance spectroscopy (600 MHz, １３ The results are shown in Table 1 together with the monomer composition.

[0435]

[0436] <Preparation of Resist Compositions> (Examples 1 to 18, Comparative Examples 1 to 3) The components shown in Table 2 were mixed and dissolved to prepare the resist compositions of each example.

[0437]

[0438] In Table 2, the abbreviations have the following meanings. The values ​​in brackets [ ] are the blend amounts (parts by mass; solid content equivalent). The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) of the copolymer are weight average molecular weights calculated in terms of standard polystyrene as determined by GPC measurement. The copolymer composition ratio (proportion (molar ratio) of each structural unit in the structural formula) is １３ It was determined by C-NMR.

[0439] (A)-1 to (A)-18: the above-mentioned copolymers (A1-0-1) to (A1-0-18).

[0440] (A)-19: A copolymer represented by the following chemical formula (A1-1-1), having a weight average molecular weight (Mw) of 7,900, a molecular weight dispersity (Mw / Mn) of 1.61, and a copolymer composition ratio l / m / n of 30 / 60 / 10.

[0441] (A)-20: A copolymer represented by the following chemical formula (A1-1-2), having a weight average molecular weight (Mw) of 5,100, a molecular weight dispersity (Mw / Mn) of 1.50, and a copolymer composition ratio l / m of 40 / 60.

[0442]

[0443] (B)-1: An acid generator comprising a compound represented by the following chemical formula (B1-1): (B)-2: An acid generator comprising a compound represented by the following chemical formula (B1-2):

[0444]

[0445] (D)-1: An acid diffusion controller consisting of a compound represented by the following chemical formula (D1-1).

[0446]

[0447] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0448] <Formation of Resist Pattern> Step of Forming Resist Film: Each resist composition of the examples was applied using a spinner onto an 8-inch silicon substrate that had been treated with hexamethyldisilazane (HMDS), and the applied resist composition was pre-baked (PAB) on a hot plate at a temperature of 110°C for 60 seconds, followed by drying to form a resist film with a thickness of 60 nm.

[0449] Step of exposing resist film: Next, the resist film was subjected to drawing (exposure) using an electron beam lithography system JEOL JBX-9300FS (manufactured by JEOL Ltd.) at an acceleration voltage of 100 kV to form a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a target size of a line width of 35 nm and a pitch width of 70 nm. Thereafter, a post-exposure bake (PEB) treatment was performed at 100°C for 60 seconds.

[0450] Step of developing the exposed resist film: Next, alkaline development was carried out for 60 seconds at 23°C using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, a water rinse was carried out for 15 seconds using pure water. As a result, an LS pattern with a line width of 35 nm and a pitch width of 70 nm was formed.

[0451] [Evaluation of Optimal Exposure Dose (Eop)] The optimal exposure dose Eop (μC / cm) for forming an LS pattern of the target size by the above <Formation of Resist Pattern> was ２ The results were recorded as "Eop (μC / cm ２ ) are shown in Table 3.

[0452] [Evaluation of Pattern Roughness Reduction (LWR)] For the LS patterns formed in the <Formation of Resist Pattern> above, 3σ, a measure of LWR, was determined. This is shown in Table 3 as "LWR (nm)." "3σ" represents three times the standard deviation (σ) (unit: nm) obtained from the measurement results of 400 line positions measured in the longitudinal direction of the lines using a scanning electron microscope (acceleration voltage 800 V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation). The smaller the 3σ value, the smaller the roughness of the line sidewalls, meaning that an LS pattern with a more uniform width was obtained.

[0453] [Evaluation of Film Loss Suppression] In the above <Formation of Resist Pattern>, the film thickness of the resist film after PAB in a large unexposed area outside the pattern and the film thickness of the resist film after water rinsing were measured, and the film thickness change rate of the resist film after water rinsing relative to the film thickness of the resist film after PAB was calculated. This is shown in Table 3 as "Remaining Film Ratio (%)". A larger value of the remaining film ratio means that the unexposed area of ​​the resist film remains without dissolving in the developer after development, and development loss (film loss) is suppressed.

[0454]

[0455] As can be seen from the results shown in Table 3, the resist compositions of Examples 1 to 18, which incorporated the present invention, achieved high sensitivity during resist pattern formation, and were more effective in reducing roughness and inhibiting film loss than the resist compositions of Comparative Examples 1 to 3.

[0456] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component whose solubility in a developer changes due to the action of the acid, the resin component comprising a copolymer having: a structural unit represented by the following general formula (a00), a structural unit represented by the following general formula (a01), and a structural unit represented by the following general formula (a02) that generates acid upon exposure. [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒ is an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group. ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ is a divalent linking group. － is an anionic group. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

2. R in the formula (a00) Ａｒ 2. The resist composition according to claim 1, wherein is an aromatic group having an iodine atom as a substituent.

3. R ​​in the formula (a01) Ｘ is an acid-dissociable group that is bonded to the oxygen atom (—O—) in —C(═O)—O— in formula (a01) via a carbon atom, and has a carbon-carbon unsaturated bond formed between the α-position of the carbon atom and the β-position of the carbon atom.

4. M in the formula (a02) ｍ＋ 2. The resist composition according to claim 1, wherein is an m-valent onium cation having a fluorine atom.

5. Z in the formula (a02) － 2. The resist composition according to claim 1, wherein is a sulfonate ion.

6. A method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to any one of claims 1 to 5, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

7. A copolymer having a structural unit represented by the following general formula (a00): a structural unit represented by the following general formula (a01): and a structural unit represented by the following general formula (a02): which generates acid upon exposure. [In formula (a00), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. Ａｒ is an aromatic group which may have a substituent, provided that the substituent which this aromatic group may have is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, an alkoxy group, and a hydroxy group. ０１ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ is a divalent linking group or a single bond. Ｘ is an acid-dissociable group. ０２ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ is a divalent linking group. － is an anionic group. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

8. R in the formula (a00) Ａｒ The copolymer according to claim 7 , wherein is an aromatic group having an iodine atom as a substituent.

9. R in the formula (a01) Ｘ is an acid-dissociable group that is bonded to the oxygen atom (—O—) in —C(═O)—O— in formula (a01) via a carbon atom and has a carbon-carbon unsaturated bond formed between the α-position of the carbon atom and the β-position of the carbon atom.

10. M in the formula (a02) ｍ＋ The copolymer according to claim 7, wherein is an m-valent onium cation having a fluorine atom.

11. Z in the formula (a02) － The copolymer of claim 7, wherein is a sulfonate ion.

12. A compound represented by the following general formula (a00-M1) or general formula (a00-M2): [In formula (a00-M1) and formula (a00-M2), R ０ａ and R ０ｂ are each independently an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ００ is a divalent linking group or a single bond. ０ｃ is at least one selected from the group consisting of a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group, and p is an integer of 1 to 4.

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