Resist composition, resist pattern formation method, compound, and polymer compound

Abstract

The present invention employs a resist composition comprising a resin component that has a structural unit derived from a compound represented by general formula (a0-m0). In the general formula, W0 represents a polymerizable-group-containing group. Rar1 represents an aromatic group that may have a substituent. L01 represents a divalent linking group or a single bond. Vb0 represents an alkylene group, a fluorinated alkylene group, or a single bond. R0 represents a fluorinated alkyl group, a fluorine atom, or a hydrogen atom. L02 represents a (p+1)-valent linking group or a single bond. p represents an integer of 1 or more. However, when L02 represents a single bond, p is 1. Rar2 represents an aromatic group that may have a substituent. q represents an integer of 1 or more. Mm+ represents an m-valent onium cation. m represents an integer of 1 or more. With this resist composition, it is possible to enhance the effects of both a decrease in roughness and suppression of film loss during resist pattern formation.

Description

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

[0001] This application claims priority to Japanese Patent Application No. 2023-116341, filed on July 14, 2023, 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 structural units containing acid generating groups that generate acid upon exposure as acid generator components (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 is effective in both reducing roughness and inhibiting film loss during resist pattern formation, a method of forming a resist pattern using the resist composition, a polymeric compound useful for the resist composition, and a compound that can be used in synthesizing the polymeric compound.

[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 (A1) whose solubility in a developer changes due to the action of the acid, and the resin component (A1) has a structural unit (a0) derived from a compound represented by the following general formula (a0-m0):

[0009] [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more.０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent; q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an m-valent onium cation, and m represents 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 compound represented by the following general formula (a0-m0):

[0012] [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent; q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more.

[0013] A fourth aspect of the present invention is a polymeric compound having a structural unit derived from the compound according to the third aspect.

[0014] According to the present invention, it is possible to provide a resist composition that exhibits improved effects of reducing roughness and suppressing film loss during resist pattern formation, a method of forming a resist pattern that uses this resist composition, a polymeric compound that is useful for this resist composition, and a compound that can be used for synthesizing this polymeric compound.

[0015] 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.

[0016] 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).

[0017] 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.

[0018] 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).

[0019] 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.

[0020] 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.

[0021] 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.

[0022] (Resist Composition) The resist composition of this embodiment generates acid upon exposure, and its solubility in a developer changes due to the action of the acid. This resist composition 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 the resist composition of this embodiment, the component (A) contains a resin component (hereafter also referred to as "component (A1)") that generates acid upon exposure, and whose solubility in a developer changes due to the action of the acid. The component (A1) has a structural unit (a0) derived from a compound represented by general formula (a0-m0) described below.

[0023]

[0043] 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) 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.

[0024] 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.

[0025] <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.

[0026] Regarding Resin Component (A1): The component (A1) is a resin component that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid. The component (A1) contains a structural unit (a0) derived from a compound represented by general formula (a0-m0) described below. In addition to the structural unit (a0), the component (A1) may contain other structural units as necessary.

[0027] <<Structural Unit (a0)>> The structural unit (a0) is a structural unit derived from a compound represented by the following general formula (a0-m0): This structural unit (a0) generates acid upon exposure during resist pattern formation.

[0028] [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent; q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more.

[0029] [Anion moiety] In the above formula (a0-m0), W ０ With regard to the polymerizable group-containing group in (1), the "polymerizable group" refers to 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. Examples of the polymerizable group include a vinyl group, an α-methylvinyl group, an allyl group, an acryloyl group, a methacryloyl group, a fluorovinyl group, a difluorovinyl group, a trifluorovinyl group, a difluorotrifluoromethylvinyl group, a trifluoroallyl group, a perfluoroallyl group, a trifluoromethylacryloyl group, a nonylfluorobutylacryloyl group, a vinyl ether group, a fluorine-containing vinyl ether group, an allyl ether group, a fluorine-containing allyl ether group, a styryl group, a vinylnaphthyl group, a fluorine-containing styryl group, a fluorine-containing vinylnaphthyl group, a norbornyl group, a fluorine-containing norbornyl group, a silyl group, and a maleimide group.

[0030] The polymerizable group-containing group may be a group composed only of 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.

[0031] Examples of the polymerizable group-containing group include a group represented by the formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０ In the above formula, R Ｘ１１ , R Ｘ１２ and R Ｘ１３ each independently represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom; ｘ０ represents a single bond or a divalent linking group. ｘ０ Examples of the divalent linking group in the above formula include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ｘ０Examples of the divalent linking group in the formula (I) 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, or a combination thereof.

[0032] In the formula (a0-m0), R ａｒ１ The aromatic group in the formula (I) is a 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. The aromatic ring is preferably an aromatic hydrocarbon ring, more preferably benzene or naphthalene, and particularly preferably benzene.

[0033] The R ａｒ１In the aromatic group in the formula (I), a hydrogen atom of the aromatic group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic 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. 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. The alkoxy group as the 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 even more preferably a methoxy group or an ethoxy group. The halogen atom as the substituent is preferably a fluorine atom, a bromine atom, or an iodine atom, and more preferably an iodine atom. Examples of the halogenated alkyl group as the substituent include alkyl groups having 1 to 5 carbon atoms, such as methyl groups, ethyl groups, propyl groups, n-butyl groups, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the halogen atoms.

[0034] In the formula (a0-m0), L ０１ In the formula (I), examples of the divalent linking group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0035] A divalent hydrocarbon group which may have a substituent: L ０１ The optionally substituted divalent hydrocarbon group in the formula (I) may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0036] Aliphatic hydrocarbon group: An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated (for example, an alkenylene group, an alkynylene group, etc.). Examples of the aliphatic hydrocarbon group include a chain aliphatic hydrocarbon group and an aliphatic hydrocarbon group containing a ring in its structure. The chain aliphatic hydrocarbon group may be a straight-chain aliphatic hydrocarbon group or a branched-chain aliphatic hydrocarbon group.

[0037] ...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 chain 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 chain aliphatic hydrocarbon group, a branched chain 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 ２alkylethylene 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.

[0038] The linear or branched aliphatic hydrocarbon group may or may not have a substituent.

[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) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 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 preferably has 3 to 6 carbon atoms, and specific examples include cyclopropane, 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.

[0040] 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. Some of the carbon atoms constituting the ring structure of the cyclic aliphatic hydrocarbon group 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.

[0041] 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. 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. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in 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.

[0042] 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.

[0043] Divalent linking group containing a hetero atom: L０１ In the formula (I), 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-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as a hydrocarbon group, an acyl group or an alkoxyalkyl group), -S-, -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 -O-C(=O)-O-, -Y ２１ -NH-, -[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. 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 a hydrocarbon group, an acyl group, or an alkoxyalkyl group. The substituent preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms.

[0044] 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 same as those described above. ２１ and Y ２２ Each of Y is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group. ２１ and Y ２２ As each of the groups, a linear or branched aliphatic hydrocarbon group or a linear or branched fluorinated aliphatic hydrocarbon group is preferable, and a linear or branched alkylene group having 1 to 5 carbon atoms or a linear or branched fluorinated alkylene group is more preferable.

[0045] L ０１ is preferably a linear or branched aliphatic hydrocarbon group, an ester bond [—C(═O)—O— or —O—C(═O)—], an ether bond (—O—), —NH—, a combination thereof, or a single bond. ０１ Examples of the bond include an ester bond [—C(═O)—O— or —O—C(═O)—], —NH—, and a bond represented by the general formula —Y ２１ a group represented by —C(═O)—O—, a group represented by the general formula —C(═O)—O—Y ２１ a group represented by the general formula -Y ２１ A group represented by —O—C(═O)—O—, or a group represented by the general formula —Y ２１ A group represented by —NH— is preferred.

[0046] In the formula (a0-m0), Vb ０ The alkylene group in may be linear or branched. The linear alkylene 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. Examples of the linear alkylene group include a methylene group [—CH２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched alkylene 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. Examples of the branched alkylene group include -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 -, -CH２ CH (CH ３ ) CH ２ CH ２ Examples of alkyl groups include alkyl tetramethylene groups such as -. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. ０ As the fluorinated alkylene group in Vb ０ In the above formula, some or all of the hydrogen atoms constituting the alkylene group are substituted with fluorine atoms. ０ is a methylene group (-CH ２ -), -CH ２ -CH ２ -CHF-, -CH(CF ３ )- is preferred.

[0047] In the formula (a0-m0), R ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, preferably a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom, and more preferably a fluorine atom.

[0048] In the formula (a0-m0), L ０２ In the formula (L), the (p+1)-valent linking group is preferably a linking group containing an oxygen atom. ０２ When is a linking group containing an oxygen atom, examples thereof include non-hydrocarbon oxygen atom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an amide bond (-C(=O)-NH-), a carbonyl group (-C(=O)-), and a carbonate bond (-O-C(=O)-O-), as well as linking groups containing a combination of such non-hydrocarbon oxygen atom-containing linking groups and hydrocarbon groups. In addition to these combinations, a sulfonyl group (-SO ２ -) may be linked.

[0049] In the formula (a0-m0), p represents an integer of 1 or more, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, and particularly preferably 1. ０２ represents a single bond, p is 1.

[0050] In the formula (a0-m0), R ａｒ２ The aromatic group in the formula (I) is a 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. The aromatic ring is preferably an aromatic hydrocarbon ring, more preferably benzene or naphthalene, and particularly preferably benzene.

[0051] The R ａｒ２ In the aromatic group in the formula (I), a hydrogen atom of the aromatic group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic 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. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent are described in the above-mentioned R ａｒ１ Among these, from the viewpoints of increasing sensitivity during resist pattern formation and suppressing film loss in unexposed areas of the resist film, R ａｒ２ The aromatic group in R is preferably substituted with a halogen atom, more preferably with a fluorine atom, a bromine atom or an iodine atom, and particularly preferably with an iodine atom. ａｒ２ However, it is preferably an aromatic group having at least an iodine atom bonded thereto as a substituent.

[0052] In the formula (a0-m0), q represents an integer of 1 or more, as long as valence allows, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, and particularly preferably 1.

[0053] A preferred example of the structural unit (a0) is a structural unit represented by the following general formula (a0-u0).

[0054] [In the formula, R Ｘ１３ represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. ｘ０ is a divalent linking group or a single bond. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent. r is an integer of 0 to 3. q' is an integer of 1 or more, provided that q'≦r×2+4. M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more.

[0055] In the formula (a0-u0), R Ｘ１３ 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, with a fluorine atom being particularly preferred. R Ｘ１３As 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 particularly preferred from the viewpoint of industrial availability.

[0056] In the formula (a0-u0), Ya ｘ０ Examples of the divalent linking group in the above formula include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ｘ０ The divalent linking group in is preferably an ester bond (-C(=O)-O-), an oxycarbonyl group (-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. ｘ０ is more preferably an ester bond [-C(=O)-O-, -OC(=O)-] or a single bond, and even more preferably a single bond.

[0057] In the formula (a0-u0), L ０１ , Vb ０ , R ０ , L ０２ , p and R ａｒ２ is L in the formula (a0-m0). ０１ , Vb ０ , R ０ , L ０２ , p and R ａｒ２ This is similar to the explanation for

[0058] In the formula (a0-u0), r is an integer of 0 to 3. When r is 0, the structure is a benzene structure; when r is 1, the structure is a naphthalene structure; when r is 2, the structure is an anthracene structure; and when r is 3, the structure is a tetracene structure. In the formula (a0-u0), q' is an integer of 1 or more, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, even more preferably 1 or 2, and particularly preferably 1. However, q'≦r×2+4. For example, when r is 0 and the structure is a benzene structure, q' can be 1 to 4. Furthermore, there are no particular limitations on the substitution positions of the groups bonded to the benzene.

[0059] Specific preferred examples of the anion moiety of the structural unit (a0) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066] The anion moiety of the structural unit (a0) is preferably at least one type selected from the group consisting of anions represented by the aforementioned chemical formulas (a0-an-001) to (a0-an-072), and more preferably at least one type selected from the group consisting of anions represented by the aforementioned chemical formulas (a0-an-001), (a0-an-002), (a0-an-003), and (a0-an-004). Alternatively, from the standpoint of achieving high sensitivity during resist pattern formation and suppressing film loss in unexposed portions of the resist film, the anion moiety of the structural unit (a0) is particularly preferably at least one selected from the group consisting of anions represented by the aforementioned chemical formulas (a0-an-001), (a0-an-005), (a0-an-009), (a0-an-013), (a0-an-017), (a0-an-021), (a0-an-025), (a0-an-029), (a0-an-033), (a0-an-037), (a0-an-041), (a0-an-045), (a0-an-049), (a0-an-053), (a0-an-057), (a0-an-061), (a0-an-065), and (a0-an-069).

[0067] [Cation moiety] In the formula (a0-m0), M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more. ｍ＋Among the onium cations in the formula (M), sulfonium cation and iodonium cation are more preferred. ｍ＋ ) １／ｍ Examples of the onium cation include those represented by the following general formulas (ca-1) to (ca-3).

[0068] [In the formula, R ２０１ ~R ２０７ 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—.]

[0069] 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 ２１０Examples 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.

[0070] [In the formula, R' ２０１ are 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.

[0071] 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.

[0072] 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. ２０１Specific 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.

[0073] R' ２０１ 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.

[0074] Among them, R' ２０１The 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.

[0075] 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 ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0076] 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).

[0077]

[0078] R' ２０１Examples 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

[0079] A chain alkyl group which may have a substituent: R' ２０１ The 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.

[0080] A chain alkenyl group which may have a substituent: R' ２０１The 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.

[0081] 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:

[0082] R' ２０１ In 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 groups represented by formula (a1-r-2) described below.

[0083] 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; ２For 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.

[0084] 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 Ｎ is 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.

[0085] 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.

[0086] 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. ２１０The 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.

[0087] [In the formula, 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; 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.

[0088] 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.

[0089] 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.

[0090] Specific examples of the groups represented by general formulae (b5-r-1) to (b5-r-4) are listed below, where "Ac" represents an acetyl group.

[0091]

[0092]

[0093]

[0094] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas.

[0095]

[0096]

[0097] [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 0 to 20.]

[0098]

[0099]

[0100] [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

[0101]

[0102]

[0103] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0104] 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).

[0105]

[0106] The cation moiety ((M ｍ＋ ) １／ｍ ), the cations represented by the formulas (ca-1) to (ca-3) are more preferable, the cations represented by the formula (ca-1) are even more preferable, and the cations represented by the formulas (ca-1-1) to (ca-1-87) are particularly preferable.

[0107] Alternatively, the cation moiety ((M ｍ＋ ) １／ｍ ) is selected from the viewpoints of increasing sensitivity during resist pattern formation and suppressing film loss in unexposed areas of the resist film. ｍ＋ is preferably an m-valent onium cation having a fluorine atom. ｍ＋ As the cation, a cation represented by the following formula (ca-1-f1) is preferred.

[0108] [wherein, Rf ２０１ ~Rf ２０３ Rf 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 ~Rf ２０３ may be bonded to each other to form a ring together with the sulfur atom in the formula. ２０１ ~Rf ２０３ At least one of the groups contains at least one fluorine atom.

[0109] Rf in the formula (ca-1-f1) ２０１ ~Rf ２０３ represents R in the formula (ca-1). ２０１ ~R ２０３ and the same as above, except that Rf ２０１ ~Rf ２０３ At least one of Rf contains at least one fluorine atom. The cation represented by formula (ca-1-f1) preferably contains three or more fluorine atoms. ２０１ ~Rf ２０３may have three or more fluorine atoms, and Rf ２０１ ~Rf ２０３ The total number of fluorine atoms contained in the cation moiety ((M ｍ＋ ) １／ｍ ), for example, at least one cation selected from the group consisting of cations represented by the above chemical formulas (ca-1-44), (ca-1-71) to (ca-1-83) is preferred, at least one cation selected from the group consisting of cations represented by the above chemical formulas (ca-1-71) to (ca-1-75) is more preferred, at least one cation selected from the group consisting of cations represented by the above chemical formulas (ca-1-72), (ca-1-74) and (ca-1-75) is even more preferred, and at least one cation selected from the group consisting of cations represented by the above chemical formulas (ca-1-74) and (ca-1-75) is particularly preferred.

[0110] Specific examples of the structural unit (a0) include, but are not limited to, the following: α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0111]

[0112]

[0113] The structural unit (a0) is preferably a structural unit represented by any of the above formulas (a0-u1) to (a0-u9), and more preferably a structural unit represented by any of the above formulas (a0-u1), (a0-u6), and (a0-u8).

[0114] The structural unit (a0) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a0) in the component (A1), relative to the total (100 mol%) of all structural units constituting the component (A1), is preferably 1 to 40 mol%, more preferably 2 to 30 mol%, even more preferably 5 to 25 mol%, and particularly preferably 10 to 20 mol%. When the proportion of the structural unit (a0) is at least the lower limit of the above-mentioned preferred range, the effects of reducing roughness and suppressing film loss during resist pattern formation are both more likely to be enhanced. When the proportion of the structural unit (a0) is at most the upper limit of the above-mentioned preferred range, it is easier to achieve a balance with the other structural units.

[0115] <<Other Structural Units>> The component (A1) may contain other structural units, as needed, in addition to the structural unit (a0) described above. Examples of other structural units include a structural unit (a1) containing an acid-decomposable group whose polarity increases when affected by acid; a structural unit (a10) represented by general formula (a10-1) described below; a structural unit (a5) that generates acid upon exposure (excluding those corresponding to the structural unit (a0)); 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.

[0116] Regarding the structural unit (a1): The structural unit (a1) is a structural unit that contains an acid-decomposable group whose polarity increases under the action of an acid. Examples of the acid-dissociable group that constitutes the acid-decomposable group include those that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions. Examples of acid-dissociable groups that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions include "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," "tertiary alkyloxycarbonyl acid-dissociable groups," and "secondary alkyl ester-type acid-dissociable groups."

[0117] Acetal-Type Acid-Dissociable Group: Among the polar groups, examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter, sometimes referred to as "acetal-type acid-dissociable group"):

[0118] [In the formula, Ra' １ , Ra' ２ is 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.]

[0119] 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, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester above, and alkyl groups having 1 to 5 carbon atoms are preferred. Specific examples include linear or 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.

[0120] 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, 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.

[0121] 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, with an isopropyl group being preferred.

[0122] Ra' ３ When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. As an alicyclic 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 alicyclic 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.

[0123] 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.

[0124] 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 alicyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic 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 cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, and cyclododecyl; and polycyclic aliphatic saturated hydrocarbon groups such as bicyclo[2.2.2]octanyl, tricyclo[5.2.1.02,6]decanyl, tricyclo[3.3.1.13,7]decanyl, tetracyclo[6.2.1.13,6.02,7]dodecanyl, and adamantyl. 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, and phenanthrene.

[0125] 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.

[0126] Tertiary alkyl ester acid-dissociable group: Among the above polar groups, examples of the acid-dissociable group protecting the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2): Of the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group will hereinafter be referred to as "tertiary alkyl ester acid-dissociable groups" for convenience.

[0127] [In the formula, Ra' ４ ~Ra'６ are each a hydrocarbon group, and Ra' ５ , Ra' ６ may be bonded to each other to form a ring.

[0128] Ra' ４ Examples of the hydrocarbon group of Ra' include a linear or branched alkyl group, a linear or cyclic alkenyl group, a linear alkynyl group, and a cyclic hydrocarbon group. ４ The linear or branched alkyl group and the cyclic hydrocarbon group (the alicyclic hydrocarbon group which is a monocyclic group, the alicyclic hydrocarbon group which is a polycyclic group, and the 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.

[0129] 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).

[0130] [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' １０ represents 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. Ra １０１ ~Ra１０３ 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 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).

[0131] 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.

[0132] Ra' 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.

[0133] 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.

[0134] 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, monocyclic alicyclic hydrocarbon groups are preferred, and specifically, cyclopentyl and cyclohexyl groups are more preferred.

[0135] In the formula (a1-r2-2), the cyclic hydrocarbon group formed by Xa together with Ya includes Ra' in the formula (a1-r-1). ３ Examples of the cyclic hydrocarbon group include a group in which one or more hydrogen atoms have been further removed from a cyclic monovalent hydrocarbon group (alicyclic hydrocarbon group) in the formula: 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 １０３In the formula (I), 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; and polycyclic aliphatic saturated hydrocarbon groups such as a bicyclo[2.2.2]octanyl group, a tricyclo[5.2.1.02,6]decanyl group, a tricyclo[3.3.1.13,7]decanyl group, a tetracyclo[6.2.1.13,6.02,7]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.

[0136] 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.

[0137] Ra １０１ ~Ra １０３ Examples 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.

[0138] In formula (a1-r2-3), the aliphatic cyclic group formed by Xaa together with Yaa is Ra' in formula (a1-r-1). ３ In formula (a1-r2-3), the groups exemplified as the alicyclic hydrocarbon group are preferably monocyclic or polycyclic groups. 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. １０４is 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.

[0139] 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 hydroxyl group, a carboxyl 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.

[0140] 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 an alkyl group having 1 to 5 carbon atoms, further 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] Ra' １４ When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. As an alicyclic 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 alicyclic 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.

[0145] 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.

[0146] 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.

[0147] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0148]

[0149]

[0150]

[0151] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0152]

[0153]

[0154]

[0155] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0156]

[0157] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0158]

[0159] Tertiary alkyloxycarbonyl acid dissociable group: Examples of the acid dissociable group that protects the hydroxyl group of the polar group include acid dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience, may be referred to as "tertiary alkyloxycarbonyl acid dissociable group").

[0160] [In the formula, Ra' ７ ~Ra' ９ are each an alkyl group.

[0161] 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.

[0162] Secondary Alkyl Ester-Type Acid-Dissociable Group: Among the above polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-4).

[0163] [In the formula, Ra' １０ is a hydrocarbon group. １１ａ and Ra' １１ｂ are each independently a hydrogen atom, a halogen atom or an alkyl group. １２ is a hydrogen atom or a hydrocarbon group. 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.

[0164] In the formula, Ra' １０ and Ra' １２The 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' is the same as the alkyl group in １０ and Ra' １２ and the hydrocarbon group in Ra' １１ａ and Ra' １１ｂ The alkyl group in may have a substituent. Examples of the substituent include the above-mentioned Ra ｘ５ etc.

[0165] 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.

[0166] 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.

[0167] Ra' １０ and Ra' １１ａ or Ra' １１ｂ The ring formed by bonding these may be a fused ring. Specific examples of such a fused ring include indan.

[0168] Ra' １０ and Ra' １１ａ or Ra' １１ｂ The ring formed by bonding together may have a substituent. Examples of the substituent include the above-mentioned Ra ｘ５ etc.

[0169] Ra' １１ａor 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.

[0170] Specific examples of the group represented by the formula (a1-r-4) are listed below.

[0171]

[0172] Examples of the structural unit (a1) include 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, a structural unit derived from acrylamide, a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least some of the hydrogen atoms in the hydroxyl groups are protected with a substituent containing the above-mentioned acid-decomposable group, and a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative in which at least some of the hydrogen atoms in -C(═O)-OH are protected with a substituent containing the above-mentioned acid-decomposable group.

[0173] Of the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Preferred specific examples of such a structural unit (a1) include structural units represented by the following general formula (a1-1), general formula (a1-2), or general formula (a1-3).

[0174] [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 is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). １ is n ａ２ + is a monovalent hydrocarbon group. ａ２is an integer from 1 to 3. ２ represents an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3). 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.

[0175] In the formulas (a1-1) to (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.

[0176] In the formula (a1-1), Va １ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0177] 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.

[0178] 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(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(CH３ ) 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.

[0179] 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.

[0180] Va １The 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.

[0181] 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-r2-1), 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.

[0182] In the formula (a1-2), Wa １ n in ａ２The +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 combining linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in the structure. ａ２ The +1 valence 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).

[0183] 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.

[0184] 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. ０１Among 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.

[0185] 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.

[0186] In the formula (a1-3), Rz ０１ The 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.

[0187] 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, two or more Rz ０１may 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.

[0188] Specific examples of the structural unit (a1) are shown below. 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.

[0189]

[0190]

[0191]

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203] The structural unit (a1) contained in the component (A1) may be of one type, or may be of two or more types. As the structural unit (a1), a structural unit represented by the above formula (a1-1) or a structural unit represented by the above formula (a1-3) is more preferred, as these tend to further improve the properties (sensitivity, shape, etc.) in lithography using electron beams or EUV. Among these, an acid-dissociable group (Ra １ , Rax ０１ It is preferable to select a group in which the acid-dissociable group (Ra) is a cyclic group. １ , Rax ０１ ) are preferably acid-dissociable groups represented by the above general formula (a1-r2-1), (a1-r2-2), (a1-r2-3), (a1-r2-4) or (a1-r-4), respectively, and among these, it is particularly preferable to select those which are cyclic groups.

[0204] Alternatively, the structural unit (a1) is a structural unit represented by the above formula (a1-1), and Ra １ is more preferably an acid-dissociable group represented by the above general formula (a1-r-2) or (a1-r-4); １ is more preferably an acid-dissociable group represented by the above general formula (a1-r-2), and among these, it is particularly preferable that the structural unit represented by the above formula (a1-1), １ is an acid-dissociable group represented by the above general formula (a1-r2-1), a structural unit represented by the above formula (a1-1), １ is an acid-dissociable group represented by the above general formula (a1-r2-2), and the structural unit represented by the above formula (a1-1), １ is most preferably an acid-dissociable group represented by the above general formula (a1-r2-2).

[0205] The proportion of the structural unit (a1) in the component (A1) is preferably 20 to 75 mol%, more preferably 25 to 70 mol%, even more preferably 40 to 60 mol%, and particularly preferably 45 to 55 mol%, based on the total (100 mol%) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a1) is at least the lower limit of the above-mentioned preferred range, it becomes easier to achieve high sensitivity and etching resistance, and it also becomes easier to improve roughness and exposure latitude. 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, and various lithography properties become favorable.

[0206] Regarding the structural unit (a10): The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0207] [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.

[0208] In the formula (a10-1), R is the same as R in the general formula (a1-1). 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.

[0209] 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.

[0210] Divalent hydrocarbon group which may have a substituent: The divalent hydrocarbon group which may have a substituent may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0211] Aliphatic hydrocarbon group: An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups that contain a ring in their structure.

[0212] ...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 chain 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 chain aliphatic hydrocarbon group, a branched chain 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(CH３ ) 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.

[0213] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0214] ...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) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 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 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.

[0215] 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 hydroxyl 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. The alkoxy group as the 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 even more preferably a methoxy group or an ethoxy group. The halogen atom as the substituent is preferably a fluorine atom. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0216] 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. 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. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in 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.

[0217] In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be 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 hydroxyl 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 those exemplified as the substituent substituting a hydrogen atom of the cyclic aliphatic hydrocarbon group.

[0218] Divalent linking group containing a hetero atom: 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 ２２are 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. 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 or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. In the 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 same as those described above. 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. ２１ -C(=O)-O] ｍ” -Y ２２ In 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.

[0219] Ya ｘ１ is 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)-].

[0220] 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 ｘ１The 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.

[0221] Wa ｘ１ The 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. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include Ya ｘ１ Examples of the substituent include the same as those exemplified as the substituent of the cyclic alicyclic hydrocarbon group in (1). 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.

[0222] 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.

[0223] 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.

[0224]

[0225]

[0226]

[0227] The structural unit (a10) that the component (A1) can have may be one type, or two or more types. The component (A1) may or may not have the structural unit (a10), but preferably has the structural unit (a10). When the component (A1) has the structural unit (a10), the proportion of the structural unit (a10) in the component (A1) is preferably 10 to 60 mol %, more preferably 15 to 50 mol %, and even more preferably 20 to 40 mol %, relative to the total (100 mol %) of all structural units that make up the component (A1). By ensuring that the proportion of the structural unit (a10) is at or above the lower limit, sensitivity is more likely to be increased. On the other hand, by ensuring that the proportion is at or below the upper limit, it is easier to achieve a balance with other structural units.

[0228] Regarding the structural unit (a5): In the resist composition of this embodiment, the structural unit (a5) is a structural unit that generates acid upon exposure, and known structural units can be used. The structural unit (a5) does not include those that fall under the structural unit (a0). By including the structural unit (a5), the acid generated upon exposure tends to be more uniformly distributed within the resist film. Suitable examples of the structural unit (a5) include structural units represented by the following general formula (a5-1):

[0229] [In the formula, R ｍ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. １ is a divalent linking group or a single bond. ０５０ represents a divalent hydrocarbon group which may have a substituent. ａ５ is an integer from 0 to 2. ０ is a divalent linking group. ０ is a divalent linking group which may have a heteroatom, or a single bond. ０５１ and Ra ０５２ are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group, n0 is an integer of 1 to 4, m is an integer of 1 or more, and M' ｍ＋ is an m-valent onium cation.

[0230] {Anion moiety} In the formula (a5-1), R ｍ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. ｍ 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 ｍ 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 most preferred in terms of industrial availability.

[0231] In the formula (a5-1), La １ is a divalent linking group or a single bond. １ The divalent linking group in the formula (I) is not particularly limited, but a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom are preferred. ｘ１ The divalent linking group is the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom exemplified in the above. １ 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. １ is more preferably an ester bond [—C(═O)—O—, —O—C(═O)—] or a single bond, and further preferably an ester bond [—C(═O)—O—, —O—C(═O)—].

[0232] In the formula (a5-1), Ra ０５０ is a divalent hydrocarbon group which may have a substituent. ０５０ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0233] .Ra ０５０ The 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, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0234] ...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 ) (CH２ 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.

[0235] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0236] ...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) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 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 preferably has 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. 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.

[0237] 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 hydroxyl group, and a carbonyl group. The alkyl group as the 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 the 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. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0238] .Ra ０５０The 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. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in 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.

[0239] In the aromatic hydrocarbon group, a hydrogen atom contained in the aromatic hydrocarbon group may be 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 hydroxyl group. The alkyl group as the 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. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include those exemplified as the substituent that substitutes a hydrogen atom contained in the cyclic aliphatic hydrocarbon group.

[0240] n ａ５ is an integer of 0 to 2. Among the above, Ra ０５０ is preferably an aliphatic hydrocarbon group containing a ring in its structure, more preferably a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure, and even more preferably an alicyclic hydrocarbon group which is a polycyclic group or a monocyclic group and may have a substituent. ０５０ is preferably an aromatic hydrocarbon group.

[0241] n ａ５ If is 2, then two Ra ０５０ may all be alicyclic hydrocarbon groups which may have a substituent, may all be aromatic hydrocarbon groups, or may be a combination of alicyclic hydrocarbon groups which may have a substituent and aromatic hydrocarbon groups.

[0242] In the formula (a5-1), La ０ is a divalent linking group. ０Examples of the divalent linking group in the formula (I) include non-hydrocarbon oxygen atom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an amide bond (-C(=O)-NH-), a carbonyl group (-C(=O)-), and a carbonate bond (-O-C(=O)-O-); and combinations of such non-hydrocarbon oxygen atom-containing linking groups with alkylene groups. These combinations may also be further combined with a sulfonyl group (-SO ２ -) may be linked. Examples of such a divalent linking group include the linking groups represented by the general formulae (y-al-1) to (y-al-8) described below. In the general formulae (y-al-1) to (y-al-8) described below, Ra ０５０ The group that bonds to V' in the general formulae (y-al-1) to (y-al-8) is １０１ is.

[0243] La ０ As the linking group, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, and linking groups represented by the below-described general formulae (y-al-1) to (y-al-6) and (y-al-8) are more preferable, and linking groups represented by the general formula (y-al-3), (y-al-6) or (y-al-8) are even more preferable.

[0244] In the formula (a5-1), Ya ０ represents a divalent linking group which may have a heteroatom, or a single bond. ０ 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. ０ The divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in ｘ１ The divalent linking group is the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom exemplified in the above. ０ is preferably a linear or branched alkylene group or a single bond, and more preferably a single bond.

[0245] In the formula (a5-1), Ra ０５１ and Ra ０５２ are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group. ０５１ and Ra ０５２ In the formula (a5-1), the fluorinated alkyl group is preferably a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms, and more preferably a trifluoromethyl group. ３ － Ra bonded to the carbon atom adjacent to ０５１ and Ra ０５２ From the viewpoint of acid strength, it is preferable that at least one of the groups is a fluorine atom.

[0246] In the formula (a5-1), n0 represents an integer of 1 to 4, and is preferably 1, 2, or 3.

[0247] {Cation moiety} In the formula (a5-1), M' ｍ＋ represents an m-valent onium cation. ｍ＋ represents m and M in the general formula (a0-m0). ｍ＋ is the same as:

[0248] Specific preferred examples of the structural unit (a5) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. ｍ＋ represents m and M' in the general formula (a5-1). ｍ＋ is the same as:

[0249]

[0250]

[0251]

[0252] The structural unit (a5) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a5), the proportion of the structural unit (a5) in the component (A1) is preferably 5 to 25 mol %, more preferably 10 to 20 mol %, and even more preferably 15 to 20 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a5) is at least the lower limit of the above-mentioned preferred range, it becomes easier to achieve even higher sensitivity and reduced roughness. On the other hand, when the proportion is at most the upper limit of the above-mentioned preferred range, it becomes easier to achieve a balance with the other structural units.

[0253] Regarding the structural unit (a2): The component (A1) may further include a structural unit (a2) (excluding those corresponding to the structural unit (a1)) that includes a lactone-containing cyclic group. When the component (A1) 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 solubility during development, resulting in improved lithography properties.

[0254] 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).

[0255] [In the formula, Ra' ２１are 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).

[0256] In the general formulas (a2-r-1) to (a2-r-7), Ra' ２１ The 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.

[0257] 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, groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; ２，６ ] decane, tetracyclododecane, and other polycycloalkanes in which one or more hydrogen atoms have been removed. Examples of the lactone-containing cyclic group in 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.

[0258] Ra' ２１ Among the above, each of the groups is preferably independently a hydrogen atom or a cyano group.

[0259] 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.

[0260] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are listed below.

[0261]

[0262]

[0263] 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):

[0264] [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.

[0265] In the formula (a2-1), R is the same as defined above. 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.

[0266] 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 general formula (a10-1), ｘ１ Examples of the divalent linking group include the same as the divalent linking group in the above formula.

[0267] Ya 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.

[0268] In the formula (a2-1), Ya ２１ is a single bond, and La ２１ is preferably —COO— or —OCO—.

[0269] 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.

[0270] The component (A1) may contain one type of structural unit (a2), or two or more types. The component (A1) may or may not contain the structural unit (a2). When the component (A1) contains 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 constituting the component (A1). 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 upper limit, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0271] 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).

[0272] [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 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.

[0273] 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.

[0274] 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.

[0275] 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.

[0276] Specific examples of the structural unit (a8) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0277]

[0278] Among the above examples, the structural unit (a8) is preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), (a8-1-06), (a8-1-08), (a8-1-09), and (a8-1-10), and more preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), and (a8-1-09).

[0279] The component (A1) may have one type of structural unit (a8), or two or more types. The component (A1) may or may not have the structural unit (a8). When the component (A1) has the structural unit (a8), the proportion of the structural unit (a8) in the component (A1) 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 constituting the component (A1).

[0280] The resist composition may contain one type of component (A1), or two or more types of components may be used in combination.

[0281] In the resist composition of this embodiment, the resin component (A1) has a structural unit (a0) derived from a compound represented by the above general formula (a0-m0). A preferred example of the component (A1) is one that has the structural unit (a0) and a structural unit (a1) that contains an acid-decomposable group whose polarity increases when exposed to acid. A more preferred example of the component (A1) is a polymeric compound that has a repeating structure of the structural unit (a0), the structural unit (a1), and the structural unit (a10), and even more preferred is a polymeric compound that consists solely of a repeating structure of the structural unit (a0), the structural unit (a1), and the structural unit (a10).

[0282] In polymeric compounds having a repeating structure of the structural unit (a0), the structural unit (a10), and the structural unit (a1), the proportion of the structural unit (a0) is preferably 2 to 30 mol%, more preferably 5 to 25 mol%, and even more preferably 5 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. Furthermore, the proportion of the structural unit (a1) in the polymeric compound is preferably 10 to 80 mol%, more preferably 15 to 75 mol%, and even more preferably 20 to 70 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. Furthermore, the proportion of the structural unit (a10) in the polymeric compound is preferably 10 to 60 mol%, more preferably 15 to 50 mol%, and even more preferably 20 to 40 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. However, the total proportion of the structural unit (a0), the structural unit (a1), and the structural unit (a10) does not exceed 100 mol%.

[0283] The component (A1) can be produced by dissolving the monomers that derive each structural unit in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing the resulting mixture. Alternatively, the component (A1) can be produced by dissolving a monomer that derives the structural unit (a0) and, if necessary, a monomer that derives a structural unit other than the structural unit (a0) (e.g., the structural unit (a10)) in a polymerization solvent, adding a radical polymerization initiator such as those described above to the solution and polymerizing the resulting mixture, followed by a deprotection reaction. During the polymerization, for example, HS-CH 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).

[0284] The weight-average molecular weight (Mw) of component (A1) (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) 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) 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.

[0285] Regarding resin component (A2): The resist composition of this embodiment may also use, as the component (A), a base component (hereafter referred to as "component (A2)") that does not fall under the category of the component (A1) and whose solubility in a developer changes under the action of acid. 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 compound or a low molecular weight compound, and may be used either alone, or in combination of two or more types.

[0286] The proportion of the component (A1) within the component (A), relative to the total weight of the component (A), is preferably 25% by weight or more, more preferably 50% by weight or more, and even more preferably 75% by weight or more, and may even be 100% by weight. When this proportion is 25% by weight or more, a resist pattern that is excellent in various lithography properties, such as high sensitivity, resolution, reduced roughness, and suppressed film loss, is more likely to be formed.

[0287] 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.

[0288] <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).

[0289] <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. The component (B) may be contained in the form of a compound, or may be incorporated into a base material component in addition to the structural unit (a0) described above as a structural unit that generates an acid upon exposure, or may take both of these forms.

[0290] 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)"):

[0291] [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 fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom. １０１is 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 V １０１ 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.

[0292] {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.

[0293] 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.

[0294] 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.

[0295] 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.

[0296] 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.

[0297] 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.

[0298] Also, R １０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the above general formulae (a2-r-1) to (a2-r-7), —SO 2 represented by the above 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). １０１ represents a bond bonded to

[0299] 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

[0300] 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

[0301]

[0302] 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.

[0303] 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.

[0304] 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.

[0305] 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:

[0306] 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-a1-8). In the following general formulas (y-a1-1) to (y-a1-8), R in the above formula (b-1) １０１ The bond to V' in the following general formulae (y-al-1) to (y-al-8) is １０１ is.

[0307] [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.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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).

[0313] [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.

[0314] 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).

[0315] 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).

[0316] 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.

[0317] 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.

[0318] 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.

[0319] 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).

[0320] {Cation Moiety} In the formula (b-1), formula (b-2), and formula (b-3), M' ｍ＋ represents an m-valent onium cation. ｍ＋ represents m and M in the general formula (a0-m). ｍ＋ Among these, sulfonium cations and iodonium cations are preferred. m is an integer of 1 or more.

[0321] Among the above, the cation moiety of the component (B) is preferably a sulfonium cation, more preferably the cations represented by each of the formulas (ca-1) to (ca-3), still more preferably the cation represented by the formula (ca-1), and particularly preferably the cations represented by each of the formulas (ca-1-1) to (ca-1-85).

[0322] In the resist composition of this embodiment, the component (B) may be used alone, or two or more types may be used in combination. In the resist composition, the amount of the component (B) relative to 100 parts by mass of the component (A1) is preferably less than 50 parts by mass, more preferably 0 to 40 parts by mass, even more preferably 0 to 30 parts by mass, and even more preferably 0 to 20 parts by mass. By ensuring that the amount of the component (B) falls within the above-mentioned preferred range, sufficient pattern formation is achieved. Furthermore, this is preferable because when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is improved.

[0323] <<Base Component (D)>> In addition to the component (A), the resist composition of this embodiment may further 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.

[0324] Regarding the component (D1): By using a resist composition containing the component (D1), the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern. 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 function as quenchers, but function as quenchers in the unexposed areas of the resist film.

[0325] [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. ２In 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 organic cation.

[0326] {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 general formulas (y-al-1) to (y-al-8). Note that Rd １ In the case where the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group in the formula (d1-1) has a linking group represented by the general formulas (y-al-1) to (y-al-8) as a substituent, in the general formulas (y-al-1) to (y-al-8), Rd 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-8) 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.

[0327] 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.

[0328] Specific examples of preferred anion moieties of component (d1-1) are shown below.

[0329]

[0330] ...cation moiety In formula (d1-1), M ｍ＋ is an m-valent organic cation. ｍ＋ Suitable examples of the organic cation include the same as the cations represented by the general formulas (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 formulas (ca-1-1) to (ca-1-85) being even more preferred. One type of component (d1-1) may be used alone, or two or more types may be used in combination.

[0331] {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. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10 carbon atoms. 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, or the like. 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.

[0332] Specific examples of preferred anion moieties of component (d1-2) are shown below.

[0333]

[0334] In formula (d1-2), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋ The component (d1-2) may be used alone or in combination of two or more.

[0335] {Component (d1-3)} Anion portion In formula (d1-3), Rd ３ 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 ２０１Among these, a fluorinated alkyl group is preferred, and the Rd １ The same fluorinated alkyl groups as those mentioned above are more preferred.

[0336] 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.

[0337] 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.

[0338] Rd ４ The cyclic group in 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.

[0339] 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 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.

[0340] Specific examples of preferred anion moieties of component (d1-3) are shown below.

[0341]

[0342]

[0343] In formula (d1-3), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋ The component (d1-3) may be used alone or in combination of two or more.

[0344] 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) in the resist composition is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of the component (A1). When the amount of the component (D1) is at least as large as the preferred lower limit, particularly favorable lithography properties and resist pattern shape are more likely to be obtained. On the other hand, when the amount is no more than the upper limit, good sensitivity can be maintained and excellent throughput can also be achieved.

[0345] 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.

[0346] 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.

[0347] 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.

[0348] 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.

[0349] 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.

[0350] 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). By ensuring that the amount is within this range, the resist pattern shape and stability over time during storage can be improved.

[0351] <<At least one compound (E) selected from the group consisting of organic carboxylic acids, phosphorus oxo acids, and derivatives thereof>> 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, phosphorus oxo acids, and derivatives thereof 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 oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Examples of derivatives of phosphorus oxo acids include esters in which the hydrogen atoms of the above oxo acids are substituted with hydrocarbon groups, with examples of the hydrocarbon groups being alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Examples of phosphoric acid derivatives include phosphate esters such as di-n-butyl phosphate and diphenyl phosphate. Examples of phosphonic acid derivatives include phosphonate esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Examples of phosphinic acid derivatives include phosphinic acid esters and phenylphosphinic acid. In the resist composition of this embodiment, the component (E) may be used alone or in combination with two or more different compounds. When the resist composition contains the component (E), the amount of the component (E) is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the component (A1). By using the component (E) in the above range, sensitivity, lithography properties, and the like are improved.

[0352] <Fluorine Additive Component (F)> 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 the component (A), it is possible to improve lithography properties. As the component (F), for example, 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 can be used. More specific examples of the 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 (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1), and more preferably a copolymer of the structural unit (f1) with the structural unit (a1). Here, the structural unit (a1) 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, and more preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate.

[0353] [wherein R is the same as defined above, and Rf １０２ and Rf １０３ Rf 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. １ is an integer of 0 to 5, and Rf １０１ is an organic group containing a fluorine atom.

[0354] 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), nf is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group, and still more preferably a hydrogen atom. １ is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0355] In formula (f1-1), Rf １０１ is 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 -CF２ -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.

[0356] 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.

[0357] 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) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass.

[0358] <Organic Solvent Component (S)> 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 individual components used to form a homogeneous solution, and any solvent can be appropriately selected from among those known as solvents for conventional chemically amplified resist compositions. In the resist composition of this embodiment, the component (S) can be used either alone or as a mixed solvent of two or more different solvents. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0359] Also preferred as component (S) is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into account the compatibility of PGMEA with the polar solvent, etc. Another preferred component (S) 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 component (S) used is not particularly limited and is appropriately determined based on the coating film thickness and a concentration that allows application to a substrate, etc. Component (S) 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%.

[0360] 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.

[0361] 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.

[0362] As explained above, the resist composition of this embodiment contains a resin component (A1) that has a structural unit (a0) derived from a compound represented by general formula (a0-m0). This structural unit (a0) contains an aromatic ring unit (-L ０２ - (R ａｒ２ ) p) and an anionic unit (-L ０１ -Vb ０ -CFR ０ -SO ３ －) into the resin component (A1). By introducing the acid-generating structural unit (a0) into the resin component (A1), acid is more easily generated uniformly within the resist film, and diffusion of the acid is more easily suppressed. In addition, in the structural unit (a0), the aromatic group (R ａｒ１ ) and an aromatic ring unit (-L ０２ - (R ａｒ２ )p) is bonded, acid diffusion is more easily suppressed, and solubility in a developer is controlled (for example, solubility in an alkaline aqueous solution is reduced). For these reasons, the resist composition of this embodiment, which contains a resin component (A1) having the structural unit (a0), is more effective in reducing roughness and suppressing film loss. Such a resist composition not only reduces the thickness of the resist film, but also improves etching resistance.

[0363] (Method of forming a resist pattern) The method of forming a resist pattern according to the 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 the method of forming a resist pattern is a method of forming a resist pattern carried out as follows.

[0364] 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 EUV exposure 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. Thereafter, the resist film is 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.

[0365] 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.

[0366] 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.

[0367] The wavelength used for exposure is not particularly limited, and may be an ArF excimer laser, a KrF excimer laser, or a F ２Radiation 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 useful for exposing the resist film to EUV (extreme ultraviolet) or EB (electron beam) in the step of exposing the resist film.

[0368] 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.

[0369] 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 the component (A1) (component (A1) 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.

[0370] 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.

[0371] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0372] 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.

[0373] 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).

[0374] 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.

[0375] 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).

[0376] According to the method of forming a resist pattern of the present embodiment as described above, the resist composition described above is used, and therefore the effects of reducing roughness and suppressing film loss in resist pattern formation are both significant, making it possible to form a resist pattern with a favorable shape.

[0377] The resist composition of the above-described embodiment and the various materials used in the pattern formation method of the above-described embodiment (e.g., resist solvent, developer, rinse, anti-reflective coating composition, top coat composition, etc.) preferably do not contain impurities such as metals, halogen-containing metal salts, acids, alkalis, or components containing sulfur 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, or 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).

[0378] (Compound Represented by General Formula (a0-m0)) A third aspect of the present invention is a compound represented by the following general formula (a0-m0) (hereinafter also referred to as "compound (a0-m0)").

[0379] [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent; q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more.

[0380] The explanation for the compound represented by general formula (a0-m0) (compound (a0-m0)) is the same as the explanation for the compound represented by general formula (a0-m0) described above in <<Structural Unit (a0)>>.

[0381] Preferred compounds (compounds (a0-m0)) include, for example, compounds represented by the following general formula (a0-m00).

[0382] [In the formula, R Ｘ１３ represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. ｘ０ is a divalent linking group or a single bond. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent. r is an integer of 0 to 3. q' is an integer of 1 or more, provided that q'≦r×2+4. M ｍ＋ represents an m-valent onium cation, and m represents an integer of 1 or more.

[0383] In the formula (a0-m00), R Ｘ１３ , Ya ｘ０ , L ０１ , Vb ０ , R ０ , L ０２ , p, R ａｒ２ , r, q', M ｍ＋ and m is R in the above general formula (a0-u0). Ｘ１３ , Ya ｘ０ , L ０１ , Vb ０ , R ０ , L ０２ , p, R ａｒ２ , r, q', M ｍ＋ and m, respectively.

[0384] Specific preferred examples of the anion moiety of the compounds (a0-m0) are shown below. In each of the following formulae, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0385]

[0386]

[0387]

[0388]

[0389]

[0390]

[0391] Regarding the cation moiety of the compound (a0-m0), (M ｍ＋ ) １／ｍExamples of the onium cation in include a sulfonium cation, an iodonium cation, an ammonium cation, etc. Examples of the sulfonium cation and the iodonium cation here include the same sulfonium cations and the iodonium cations exemplified in the description of the [cation moiety] above.

[0392] (M ｍ＋ ) １／ｍ Examples of the ammonium cation in the formula (ca-4) include organic ammonium cations represented by the following general formula (ca-4).

[0393] [In the formula, R １ ~R ４ are each independently a hydrocarbon group which may have a substituent. １ ~R ４ At least two of these may be bonded to each other to form an alicyclic structure together with the nitrogen atom in the formula.

[0394] In the general formula (ca-4), R １ ~R ４ The hydrocarbon groups in R are each independently preferably hydrocarbon groups having 1 to 15 carbon atoms, more preferably hydrocarbon groups having 1 to 10 carbon atoms. １ ~R ４ The total number of carbon atoms in the hydrocarbon group is preferably 1 to 20, more preferably 3 to 18, and even more preferably 4 to 15.

[0395] R １ ~R ４The hydrocarbon group in each of the above may be a linear or branched alkyl group, or a cyclic hydrocarbon group. The linear or branched alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 5 carbon atoms. The cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The alicyclic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The aromatic hydrocarbon group is preferably a phenyl group or a benzyl group.

[0396] R １ ~R ４ Examples of the substituent that the hydrocarbon group may have include an alkoxy group, a hydroxyl group, an oxo group (=O), and an amino group.

[0397] Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following chemical formulas (ca-4-1) to (ca-4-4).

[0398]

[0399] The compounds (a0-m0) preferably mentioned above further contain a cation moiety (M ｍ＋ ) １／ｍ is preferably a sulfonium cation or an iodonium cation, more preferably an onium cation represented by any one of the above general formulas (ca-1) to (ca-3), and particularly preferably a sulfonium cation represented by the above general formula (ca-1).

[0400] The compound (a0-m0) is a compound represented by R ａｒ２ and the compound (a0-m0) is an aromatic group having at least one iodine atom bonded thereto as a substituent. ｍ＋is an m-valent onium cation having a fluorine atom, and a compound in which the cation is represented by the above formula (ca-1-f1) is particularly preferred.

[0401] Specific examples of the compounds (a0-m0) are listed below, but are not limited to these. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0402]

[0403]

[0404] [Method for Producing Compounds] The compounds (a0-m0) of this embodiment can be produced by appropriately combining known methods. For example, the compounds (a0-m0) can be produced by combining raw materials (W) corresponding to the target compound as in [Synthesis Example 1: Synthesis of Compound (a0-m01)] described later. ０ The raw material corresponding to R ａｒ１ and R ａｒ２ and using a production method including a first step (condensation, etc.), a second step (condensation, etc.), and a third step (salt exchange, etc.).

[0405] The compound of this embodiment described above can be used as a raw material monomer for a polymer compound according to the fourth aspect described below.

[0406] (Polymer Compound) A fourth aspect of the present invention is a polymer compound having a structural unit derived from the compound related to the third aspect of the present invention described above. The structural unit derived from the compound related to the third aspect is a structural unit derived from the compound represented by the above general formula (a0-m0), and is the same as the above structural unit (a0). The polymer compound related to the fourth aspect is the same as the above explanation for the component (A1).

[0407] The polymer compound according to the fourth aspect, that is, a polymer compound having a structural unit (structural unit (a0)) derived from a compound represented by general formula (a0-m0), can be used as the base component of the resist composition according to the first aspect. Furthermore, a polymer compound that contains, in addition to the structural unit (a0), a structural unit containing an acid-decomposable group whose polarity increases under the action of acid (the structural unit (a1) described above) is useful as a base resin in a resist material for lithography. Among these, a polymer compound that contains the structural unit (a0), the structural unit (a1) described above, and a structural unit represented by general formula (a10-1) described above (structural unit (a10)) is particularly useful as a resist material for lithography exposure using EUV or EB. The polymer compound according to the fourth aspect can be a resin component that is useful as the base component of a resist composition.

[0408] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0409] <Synthesis Examples of Compounds> [Synthesis Example 1: Synthesis of Compound (a0-m01)] Step 1: Compound 0 (30 g) and tetrahydrofuran (THF) (300 g) were charged and dissolved with stirring. 1,1'-carbonyldiimidazole (CDI) (29.6 g) was added thereto, and the mixture was heated to 60°C in a water bath and stirred for 1 hour. Compound 1 (56.9 g) was added thereto and aged for 1 hour. Thereafter, ultrapure water (600 g) and methylene chloride (300 g) were charged thereto and stirred. After stirring was stopped, the aqueous layer was removed and further washed with ultrapure water (300 g). The organic layer was concentrated under reduced pressure, and the concentrated residue was crystallized from acetonitrile / methanol / tert-butyl methyl ether to obtain 63 g of a white compound (Intermediate 1).

[0410]

[0411] Step 2: Intermediate 1 (60 g), triiodobenzoic acid (72.2 g), 4-dimethylaminopyridine DMAP (1.6 g), and dichloromethane CH ２ Cl ２(600 g) was stirred at 0°C, and 1,3-diisopropylcarbodiimide DIC (18.2 g) was added thereto. 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 100.6 g of a white compound (Intermediate 2).

[0412]

[0413] Step 3: Intermediate 2 (100 g), compound 2 (56.7 g), and dichloromethane CH ２ Cl ２ The organic layer was washed five times with 300 g of ultrapure water and then concentrated under reduced pressure to obtain 114 g of compound (a0-m01).

[0414]

[0415] The resulting compound (a0-m01) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.28 (s, 1H), 8.04 (s, 1H), 7.99-7.76 (m, 12H ), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0416] Synthesis Example 2 Synthesis of Compound (a0-m02) Compound (a0-m02) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that diiodobenzoic acid was used instead of triiodobenzoic acid in Step 2 of Synthesis Example 1 described above.

[0417]

[0418] The resulting compound (a0-m02) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6,400MHz): δ (ppm) = 8.29 (s, 1H), 7.99-7.76 (m, 13H), 7.69 (d, 1H) ), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0419] Synthesis Example 3 Synthesis of Compound (a0-m03) Compound (a0-m03) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that iodobenzoic acid was used instead of triiodobenzoic acid in Step 2 of Synthesis Example 1 described above.

[0420]

[0421] The resulting compound (a0-m03) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 7.99-7.76 (m, 15H), 7.56 (m, 1H), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0422] Synthesis Example 4 Synthesis of Compound (a0-m04) Compound (a0-m04) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that benzoic acid was used instead of triiodobenzoic acid in Step 2 of Synthesis Example 1 described above.

[0423]

[0424] The resulting compound (a0-m04) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.16 (m, 2H), 7.99-7.76 (m, 12H), 7.72 (m, 1H), 7.62 (m, 2H), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0425] Synthesis Example 5 Synthesis of Compound (a0-m05) Compound (a0-m05) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that Compound 3 was used instead of Compound 2 in Step 3 of Synthesis Example 1 described above.

[0426]

[0427] The resulting compound (a0-m05) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.28 (s, 1H), 8.04 (s, 1H), 7.90 (d, 1H), 7.88-7.75 ( m, 15H), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0428] Synthesis Example 6 Synthesis of Compound (a0-m06) Compound (a0-m06) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that Compound 4 was used instead of Compound 2 in Step 3 of Synthesis Example 1 described above.

[0429]

[0430] The resulting compound (a0-m06) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.28 (s, 1H), 8.04 (s, 1H), 7.99-7.83 (m, 10H ), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0431] Synthesis Example 7 Synthesis of Compound (a0-m07) Compound (a0-m07) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that Compound 5 was used instead of Compound 2 in Step 3 of Synthesis Example 1 described above.

[0432]

[0433] The resulting compound (a0-m07) was subjected to NMR measurement, and its structure was identified from the following results. １H-NMR (DMSO-d6,400MHz): δ (ppm) = 8.55 (d, 2H), 8.45 (d, 2H), 8.28 (s, 1H), 8.01 (m, 2H), 8.04 (s, 1H), 7.90 (d, 1H), 7.79-7.60 (m, 7H), 7.41 (s, 1H), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.13 (m, 2H), 5.25 (d, 1H)

[0434] Synthesis Example 8 Synthesis of Compound (a0-m08) Compound (a0-m08) was obtained in the same manner as in Steps 1 to 3 of Synthesis Example 1, except that Compound 6 was used instead of Compound 1 in Step 1 of Synthesis Example 1 described above.

[0435]

[0436] The resulting compound (a0-m08) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6,400MHz): δ (ppm) = 8.28 (s, 1H), 8.04 (s, 1H), 7.99-7.76 (m, 12H), 7.41 (s, 1H) ), 7.29 (d, 1H), 6.72 (m, 1H), 5.76 (d, 1H), 5.25 (d, 1H), 4.6 (m, 1H), 4.23 (m, 2H), 1.89 (m, 2H)

[0437] Synthesis Example 9 Synthesis of Compound (a0-m09) Compound (a0-m09) was obtained in the same manner as in steps 1 to 3 of Synthesis Example 1, except that compound 7 was used instead of compound 1 in step 1 of Synthesis Example 1, and compound 5 was used instead of compound 2 in step 3 of Synthesis Example 1.

[0438]

[0439] The resulting compound (a0-m09) was subjected to NMR measurement, and its structure was identified from the following results. １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.28-8.04 (m, 3H), 7.89 (d, 1H), 7. 77 (d, 2H), 7.52-7.29 (m, 13H), 6.72 (m, 1H), 5.76 (d, 1H), 5.26 (d, 1H)

[0440] <Synthesis Example of Polymer Compound> [Synthesis of Polymer Compound (A1-1)] 5.0 g of compound (a10-01pre), 7.63 g of compound (a1-01), 8.47 g of compound (a0-m01), and 5.56 g of azobis(isobutyrate)dimethyl (V-601) as a polymerization initiator were dissolved in 42.85 g of methyl ethyl ketone (MEK), heated to 80° C. in a nitrogen atmosphere, and stirred for 6 hours.

[0441] Thereafter, 4.69 g of acetic acid and 67.5 g of methanol were added to the reaction solution, and the mixture was stirred at 30° C. for 18 hours. After completion of the reaction, the resulting reaction solution was precipitated in 105 g of heptane and washed. The resulting white solid was filtered and dried under reduced pressure overnight, yielding 12.21 g of the target polymer compound (A1-1).

[0442]

[0443] [Synthesis of Polymer Compounds (A1-2) to (A1-11)] Polymer compounds (A1-2) to (A1-11) were synthesized in the same manner as in the synthesis of polymer compound (A1-1) described above, except that the monomers used and the amounts used were changed. Compounds (a0-m02) to (a0-m09) described above were used as the monomers from which structural unit (a0) was derived.

[0444] The structures of the corresponding starting monomers and the resulting polymeric compounds (A1-1) to (A1-11) are shown below. In each formula, l, m, and n represent the compositional ratio of each structural unit. Compound (a10-01pre) is a precursor of structural unit (a10-01), and compound (a10-02pre) is a precursor of structural unit (a10-02).

[0445]

[0446]

[0447]

[0448]

[0449] The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) of the polymer compounds (A1-1) to (A1-11) were determined by GPC measurement (standard polystyrene equivalent). The copolymer composition ratios (proportions (molar ratios) of the structural units in the structural formulas) of the polymer compounds (A1-1) to (A1-11) were determined by carbon-13 nuclear magnetic resonance spectroscopy (600 MHz １３ C-NMR).

[0450] Polymer compound (A1-1): Weight average molecular weight (Mw) 9900, molecular weight dispersity (Mw / Mn) 1.57, l / m / n = 35 / 50 / 15 Polymer compound (A1-2): Weight average molecular weight (Mw) 9600, molecular weight dispersity (Mw / Mn) 1.54, l / m / n = 35 / 50 / 15 Polymer compound (A1-3): Weight average molecular weight (Mw) 10000, molecular weight dispersity (Mw / Mn) 1.59, l / m / n = 35 / 50 / 15 Polymer compound (A1-4): Weight average molecular weight (Mw) 9900, molecular weight dispersity (Mw / Mn) 1.60, l / m / n = 35 / 50 / 15

[0451] Polymer compound (A1-5): Weight average molecular weight (Mw) 12000, molecular weight dispersity (Mw / Mn) 1.69, l / m / n = 35 / 50 / 15 Polymer compound (A1-6): Weight average molecular weight (Mw) 13500, molecular weight dispersity (Mw / Mn) 1.53, l / m / n = 35 / 50 / 15 Polymer compound (A1-7): Weight average molecular weight (Mw) 12340, molecular weight dispersity (Mw / Mn) 1.56, l / m / n = 35 / 50 / 15 Polymer compound (A1-8): Weight average molecular weight (Mw) 9450, molecular weight dispersity (Mw / Mn) 1.59, l / m / n = 35 / 50 / 15

[0452] Polymer compound (A1-9): Weight average molecular weight (Mw) 10000, molecular weight dispersity (Mw / Mn) 1.61, l / m / n = 35 / 50 / 15 Polymer compound (A1-10): Weight average molecular weight (Mw) 9700, molecular weight dispersity (Mw / Mn) 1.56, l / m / n = 35 / 50 / 15 High molecular compound (A1-11): weight average molecular weight (Mw) 12340, molecular weight dispersity (Mw / Mn) 1.56, l / m / n=35 / 50 / 15

[0453] <Preparation of Resist Compositions> (Examples 1 to 11, Comparative Examples 1 and 2) The components shown in Table 1 were mixed and dissolved to prepare the resist compositions of each example.

[0454]

[0455] In Table 1, 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 polymer compounds are weight average molecular weights calculated in terms of standard polystyrene as determined by GPC measurement. The copolymer composition ratio (the proportion (molar ratio) of each structural unit in the structural formula) is １３ It was determined by C-NMR.

[0456] (A)-1 to (A)-11: The above-mentioned polymeric compounds (A1-1) to (A1-11).

[0457] (A)-12: A polymer compound represented by the following chemical formula (A2-1), having a weight average molecular weight (Mw) of 10,000, a molecular weight dispersity (Mw / Mn) of 1.53, and a copolymer composition ratio l / m / n of 35 / 50 / 15.

[0458] (A)-13: A polymer compound represented by the following chemical formula (A2-2), having a weight average molecular weight (Mw) of 11,000, a molecular weight dispersity (Mw / Mn) of 1.59, and a copolymer composition ratio l / m / n of 35 / 50 / 15.

[0459]

[0460] (D)-1: An acid diffusion controller consisting of a compound represented by the following chemical formula (D1-1).

[0461]

[0462] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0463] <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 50 nm.

[0464] 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 50 nm and a pitch width of 100 nm. Thereafter, a post-exposure bake (PEB) treatment was performed at 100°C for 60 seconds.

[0465] 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, a 1:1 LS pattern with a line width of 50 nm was formed.

[0466] [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 2.

[0467] [Evaluation of Pattern Roughness Reduction (LWR)] For the LS patterns formed by the <Formation of Resist Pattern> above, 3σ, a measure of LWR, was determined. This is shown in Table 2 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.

[0468] [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 2 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.

[0469]

[0470] As can be seen from the results shown in Table 2, the resist compositions of Examples 1 to 11, to which the present invention was applied, were more effective in reducing roughness and inhibiting film loss during resist pattern formation than the resist compositions of Comparative Examples 1 and 2.

[0471] 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 (A1) whose solubility in a developer changes due to the action of the acid, the resin component (A1) having a structural unit (a0) derived from a compound represented by the following general formula (a0-m0): [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent. q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an onium cation having a valence of m, and m represents an integer of 1 or more.

2. R in the above general formula (a0-m0) ａｒ２ 2. The resist composition according to claim 1, wherein is an aromatic group having at least an iodine atom bonded thereto as a substituent.

3. M in the above general formula (a0-m0) ｍ＋ 3. The resist composition according to claim 1, wherein is an m-valent onium cation having a fluorine atom.

4. The resist composition according to claim 1, wherein the resin component (A1) further comprises a structural unit (a1) containing an acid-decomposable group whose polarity increases upon the action of an acid.

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

6. A compound represented by the following general formula (a0-m0): [In the formula, W ０ represents a polymerizable group-containing group. ａｒ１ represents an aromatic group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０ represents an alkylene group, a fluorinated alkylene group, or a single bond. ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ０２ represents a (p+1)-valent linking group or a single bond, and p represents an integer of 1 or more. ０２ When R represents a single bond, p is 1. ａｒ２ represents an aromatic group which may have a substituent. q represents an integer of 1 or more, as long as the valence allows. M ｍ＋ represents an onium cation having a valence of m, and m represents an integer of 1 or more.

7. R in the above general formula (a0-m0) ａｒ２ The compound according to claim 6, wherein is an aromatic group having at least an iodine atom bonded thereto as a substituent.

8. M in the above general formula (a0-m0) ｍ＋ The compound according to claim 6 or 7, wherein is an m-valent onium cation having a fluorine atom.

9. A polymeric compound having a structural unit derived from the compound according to claim 6.

10. The polymer compound according to claim 9, further comprising a structural unit containing an acid-decomposable group whose polarity increases upon the action of an acid.

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