Resist composition and method for forming resist pattern

Abstract

To provide a resist composition improved in roughness and a resist pattern forming method using the resist composition.SOLUTION: The resist composition contains a base component and an acid generator component. The base component contains a resin component having a constituent unit (a0) represented by formula (a0-1). A ratio of the constituent unit (a0) in the resin component is 58 to 80 mol% based on all constituent units constituting the resin component. (In the formula, Ra01 represents an aromatic hydrocarbon group; and Ra02 and Ra03 each independently represent a hydrocarbon group and may be bonded together to form a ring.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resist composition and a method of forming a resist pattern. [Background technology]

[0002] In lithography, for example, a process is performed in which a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed to light, and a developing process is performed to form a resist pattern of a predetermined shape on the resist film. A resist material in which the exposed portion of the resist film changes to a property that makes it soluble in a developer is called a positive type, and a resist material in which the exposed portion changes to a property that makes it insoluble in a developer is called a negative type. 2. Description of the Related Art In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, advances in lithography technology have led to rapid progress in miniaturization of patterns. In general, miniaturization techniques involve shortening the wavelength (increasing the energy) of the exposure light source. Specifically, ultraviolet rays such as g-line and i-line have been used in the past, but currently mass production of semiconductor elements using KrF excimer lasers and ArF excimer lasers has begun. In addition, EUV (extreme ultraviolet), EB (electron beam), X-rays, and other light sources with shorter wavelengths (higher energy) than these excimer lasers are also being investigated.

[0003] Furthermore, currently, in EUV lithography and EB lithography, chemically amplified resists proposed for KrF excimer lasers, ArF excimer lasers, etc. are commonly used as resist materials because they have excellent lithographic properties such as sensitivity to EUV or EB, and resolution capable of forming a target fine resist pattern. In particular, chemically amplified resists containing an acrylic resin as the base resin are considered to have excellent lithographic properties.

[0004] In order to improve the sensitivity and roughness of fine patterns produced by lithography technology, it is important to increase the reaction rate between the base resin and the acid. To this end, efforts are being made to improve the acid-elimination properties of the protecting group of the base resin. For example, Patent Documents 1 and 2 describe resist compositions and the like that employ polymer compounds having specific acid-dissociable functional groups to improve reactivity to acids and contribute to improved solubility in a developer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-122579 A [Patent Document 2] International Publication No. 2010 / 095698 Summary of the Invention [Problem to be solved by the invention]

[0006] As lithography technology continues to advance and resist patterns become increasingly finer, there will be an increasing demand for resist materials that can form resist patterns with higher resolution while maintaining good lithography properties. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist composition with improved roughness, and a method of forming a resist pattern using the resist composition. [Means for solving the problem]

[0007] 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 an acid upon exposure and changes its solubility in a developer by the action of the acid, The composition contains a base component (A) whose solubility in a developer changes under the action of an acid, and an acid generator component (B) that generates an acid upon exposure to light, The base component (A) contains a resin component (A1) having a structural unit (a0) represented by the following general formula (a0-1): In this resist composition, the proportion of the structural unit (a0) in the resin component (A1) is 58 to 80 mol % relative to the total (100 mol %) of all structural units constituting the resin component (A1).

[0008] [ka] [In the formula, R 01 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 01 is a divalent hydrocarbon group which may have an ether bond. a01 is an integer from 0 to 2. 01 Ra is an aromatic hydrocarbon group which may have a substituent. 02 and Ra 03 each independently represents a hydrocarbon group which may have a substituent, 02 and Ra 03 may be bonded to each other to form a ring.

[0009] A second aspect of the present invention is a method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to the first aspect, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. Effect of the Invention

[0010] According to the present invention, it is possible to provide a resist composition with improved roughness, and a method of forming a resist pattern using the resist composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In this specification and claims, the term "aliphatic" is a relative concept to aromaticity and is defined as meaning a group, compound, etc. that does not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in an alkoxy group. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. The term "halogenated alkyl group" refers to an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine and iodine atoms. The term "fluorinated alkyl group" or "fluorinated alkylene group" refers to an alkyl group or alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrases "may have a substituent" or "may have a substituent" include both cases where a hydrogen atom (-H) is replaced with a monovalent group and cases where a methylene group (-CH-) is replaced with a divalent group. The term "exposure" is intended to include any concept including irradiation with radiation.

[0012] The "base component" refers to an organic compound having a film-forming ability, and preferably an organic compound having a molecular weight of 500 or more is used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved, and in addition, it becomes easier to form a nano-level resist pattern. The organic compounds used as the base component are roughly classified into non-polymers and polymers. As the non-polymers, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the term "low molecular weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000. As the polymers, those having a molecular weight of 1000 or more are usually used. Hereinafter, the term "resin", "polymer compound" or "polymer" refers to a polymer having a molecular weight of 1000 or more. As the molecular weight of the polymer, the weight average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) is used.

[0013] The term "structural unit derived from an acrylate ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylate ester. An "acrylic ester" is a compound in which the hydrogen atom at the carboxyl terminal of acrylic acid (CH2=CH-COOH) is replaced with an organic group. In the acrylic acid ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. α0 ) is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms. α0 Itaconic acid diesters in which the substituent (R α0 It 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 of the acrylic ester. Unless otherwise specified, the carbon atom at the α-position of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the carbon atom at the α-position is replaced with a substituent may be referred to as an α-substituted acrylic ester. In addition, acrylic esters and α-substituted acrylic esters may be collectively referred to as "(α-substituted) acrylic esters."

[0014] The term "structural unit derived from hydroxystyrene" refers to a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene. The term "structural unit derived from a hydroxystyrene derivative" refers to a structural unit formed by cleavage of the ethylenic double bond of a hydroxystyrene derivative. The term "hydroxystyrene derivative" refers to a concept including hydroxystyrene in which the hydrogen atom at the α-position is replaced by another substituent such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include hydroxystyrene in which the hydrogen atom at the α-position may be replaced by a substituent, in which the hydrogen atom of the hydroxyl group is replaced by an organic group; and hydroxystyrene in which the hydrogen atom at the α-position may be replaced by a substituent, in which a substituent other than a hydroxyl group is bonded to the benzene ring. The α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified. Examples of the substituent that substitutes the hydrogen atom at the α-position of the hydroxystyrene include the same as those exemplified as the substituent at the α-position in the above-mentioned α-substituted acrylic ester.

[0015] The term "structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative" refers to a structural unit formed by cleavage of the ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative. The term "vinyl benzoic acid derivative" refers to a concept including vinyl benzoic acid in which the hydrogen atom at the α-position is replaced by another substituent such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include vinyl benzoic acid in which the hydrogen atom at the α-position may be replaced by a substituent, the hydrogen atom of the carboxyl group of the vinyl benzoic acid in which the hydrogen atom at the α-position may be replaced by a substituent, and vinyl benzoic acid in which the hydrogen atom at the α-position may be replaced by a substituent, and in which a substituent other than a hydroxyl group or a carboxyl group is bonded to the benzene ring. The α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.

[0016] The term "styrene derivative" refers to a concept that includes styrene in which the hydrogen atom at the α-position is replaced with another substituent such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include hydroxystyrene in which the hydrogen atom at the α-position may be replaced with a substituent and a substituent is bonded to the benzene ring. The α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified. The terms "structural unit derived from styrene" and "structural unit derived from a styrene derivative" refer to a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative.

[0017] The alkyl group as the substituent at the α-position is preferably a linear or branched alkyl group, and specific examples thereof include alkyl groups having 1 to 5 carbon atoms (such as 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). Specific examples of the halogenated alkyl group as the substituent at the α-position include groups in which some or all of the hydrogen atoms of the above-mentioned "alkyl group as the substituent at the α-position" are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. Specific examples of the hydroxyalkyl group as the substituent at the α-position include the above-mentioned "alkyl group as the substituent at the α-position" in which some or all of the hydrogen atoms have been substituted with hydroxyl groups. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1.

[0018] In the present specification and claims, some structures represented by chemical formulas may have asymmetric carbons, and may have enantiomers or diastereomers. In such cases, a single chemical formula represents all of the isomers. These isomers may be used alone or as a mixture.

[0019] (Resist composition) The resist composition related to the first aspect of the present invention generates an acid upon exposure and changes its solubility in a developer due to the action of the acid, and contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of the acid, and an acid generator component (B) (hereinafter also referred to as "component (B)") that generates an acid upon exposure. When a resist film is formed using such a resist composition and the resist film is selectively exposed, an acid is generated from the component (B) in the exposed portion of the resist film, and the solubility of the component (A) in the developer changes due to the action of the acid, whereas the solubility of the component (A) in the developer does not change in the unexposed portion of the resist film, resulting in a difference in solubility in the developer between the exposed portion and the unexposed portion of the resist film. Therefore, when the resist film is developed, if the resist composition is a positive type, the exposed portion of the resist film is dissolved and removed to form a positive type resist pattern, and if the resist composition is a negative type, the unexposed portion of the resist film is dissolved and removed to form a negative type resist pattern.

[0020] In this specification, a resist composition that dissolves and removes an exposed portion of a resist film to form a positive resist pattern is referred to as a positive resist composition, and a resist composition that dissolves and removes an unexposed portion of a resist film to form a negative resist pattern is referred to as a negative resist composition. The resist composition of this embodiment may be a positive resist composition or a negative resist composition. In addition, the resist composition of this embodiment may be for an alkaline development process in which an alkaline developer is used for the development treatment when forming a resist pattern, or may be for a solvent development process in which a developer containing an organic solvent (organic developer) is used for the development treatment.

[0021] <Component (A)> In the resist composition of this embodiment, the component (A) preferably contains a resin component (A1) (hereinafter also referred to as "component (A1)") whose solubility in a developer changes under the action of an acid. By using the component (A1), the polarity of the base component changes before and after exposure, so that 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 the component (A1) is used, and other polymeric compounds and / or low molecular weight compounds may be used in combination with the component (A1).

[0022] When an alkaline development process is applied, the base material component containing the component (A1) is poorly soluble in an alkaline developer before exposure, and when an acid is generated from the component (B) by exposure, the polarity increases due to the action of the acid, and the solubility in an alkaline developer increases. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition on a support is selectively exposed, the exposed part of the resist film changes from poorly soluble in an alkaline developer to soluble, while the unexposed part of the resist film remains poorly soluble in an alkaline developer, and a positive resist pattern is formed by alkaline development.

[0023] On the other hand, when a solvent development process is applied, the base material component containing the component (A1) is highly soluble in an organic developer before exposure, and when an acid is generated from the component (B) upon exposure, the polarity increases due to the action of the acid, and the solubility in an organic developer decreases. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition onto a support is selectively exposed, the exposed part of the resist film changes from soluble to poorly soluble in an organic developer, while the unexposed part of the resist film remains soluble, and therefore, by developing with an organic developer, a contrast can be created between the exposed part and the unexposed part, and a negative resist pattern is formed.

[0024] In the resist composition of this embodiment, the component (A) may use either a single type, or a combination of two or more types.

[0025] Regarding component (A1) The component (A1) is a resin component whose solubility in a developer changes under the action of an acid. The component (A1) has a structural unit (a0) represented by general formula (a0-1) described below. The component (A1) may contain other structural units in addition to the structural unit (a0), as necessary.

[0026] <Structural unit (a0)> The structural unit (a0) is a structural unit represented by general formula (a0-1) shown below. The structural unit (a0) contains an acid-decomposable group whose polarity increases under the action of an acid. The term "acid-decomposable group" refers to a group having acid decomposability in which at least a portion of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid. In the structural unit (a0), the acid dissociable group [-C(Ra 01 )(Ra 02 )(Ra 03 The bond between the oxygen atom adjacent to the acid-labile group and the carboxyl group is cleaved, resulting in an increase in polarity.

[0027] [ka] [In the formula, R 01 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 01 is a divalent hydrocarbon group which may have an ether bond. a01 is an integer from 0 to 2. 01 Ra is an aromatic hydrocarbon group which may have a substituent. 02 and Ra 03 each independently represents a hydrocarbon group which may have a substituent, 02 and Ra 03 may be bonded to each other to form a ring.

[0028] In the formula (a0-1), R 01 The alkyl group having 1 to 5 carbon atoms in the formula (I) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. Among these, R 01Each of these 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 more preferable, and a methyl group is even more preferable.

[0029] In the formula (a0-1), Va 01 The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0030] Va 01 The aliphatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in the structure.

[0031] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably has 1 to 6 carbon atoms, further preferably has 1 to 4 carbon atoms, and most preferably has 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)5-], etc. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, even more preferably has 3 or 4 carbon atoms, and most preferably has 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0032] Examples of the aliphatic hydrocarbon group containing a ring in the structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group, etc. 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, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. 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 obtained by removing two hydrogen atoms from a polycycloalkane, specifically cycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0033] Va 01 The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such an aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this carbon number does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (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 (aryl group) has been substituted with an alkylene group (for example, a group in which one hydrogen atom has been further removed from the aryl group in 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 to 2, and particularly preferably 1.

[0034] In the formula (a0-1), n a01 is an integer of 0 to 2, preferably 0 or 1, and more preferably 0.

[0035] In the formula (a0-1), Ra 01 The aromatic hydrocarbon group in may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 10. The number of carbon atoms in the aromatic ring does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a furan ring, a pyridine ring, and a thiophene ring. Ra 01 Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group); a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (such as 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 (such as arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0036] Ra 01 The aromatic hydrocarbon group in may have a substituent. Examples of the substituent include -R P1 , -R P2 -OR 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 05 "), halogen atoms (fluorine atom, chlorine atom, bromine atom, etc.), and the like. Here, R P1is a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic 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 linear 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 P2 Some 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 the above-mentioned substituents or may have one or more of each 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, a decyl group, an isobutyl group, a tert-butyl group, an isopentyl group, and a neopentyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group; 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. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene. Among them, Ra 01 The aromatic hydrocarbon group in the formula (I) may have a substituent, for example, -R P1 is preferred, a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is more preferred, and a methyl group or a tert-butyl group is even more preferred.

[0037] Among them, Ra01 As the alkyl group, a phenyl group, a p-tolyl group or a 4-tert-butylphenyl group is preferable.

[0038] In the formula (a0-1), Ra 02 and Ra 03 The hydrocarbon group in the formula (I) includes a linear or branched alkyl group, or a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably has 1 to 4 carbon atoms, and further preferably has 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. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0039] The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and is preferably an isopropyl group.

[0040] Ra 02 ~Ra 03 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0041] Ra 02 and Ra03 When the cyclic hydrocarbon group in the formula (I) is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The 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, further 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 a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Ra 02 and Ra 03 Specific examples of the aromatic hydrocarbon group in the above include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or 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., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0042] R 02 and R 03 and bond to each other to form a cyclic group, the cyclic group may be a polycyclic group or a monocyclic group. In addition, the cyclic group may be an alicyclic hydrocarbon group or a condensed polycyclic hydrocarbon group in which an aromatic ring is condensed to an alicyclic hydrocarbon group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane or monocycloalkene. The monocycloalkane is preferably one having 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. The monocycloalkene is preferably one having 3 to 6 carbon atoms, specifically cyclopentene, cyclohexene, etc. The aliphatic hydrocarbon group which is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane or polycycloalkene, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically, adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. Furthermore, the polycycloalkene is preferably one having 7 to 12 carbon atoms, specifically, adamantene, norbornane, isobornene, tricyclodecene, tetracyclododecene, etc. Examples of condensed polycyclic hydrocarbon groups in which an aromatic ring is condensed to an alicyclic hydrocarbon group include groups in which one hydrogen atom has been removed from an aliphatic ring of a bicyclic compound such as tetrahydronaphthalene or indane.

[0043] R 02 and R 03 and bond to each other to form a cyclic group, a part of the carbon atoms constituting the ring structure of the cyclic group may be substituted with a heteroatom-containing substituent. Examples of the heteroatom-containing substituent include -O-, -C(=O)-, -C(=O)-O-, -S-, -S(=O)2-, -S(=O)2-O-, etc., with -O-, -C(=O)-, and -C(=O)-O- being preferred, and -O- being more preferred.

[0044] Ra 02 and Ra 03 The hydrocarbon group in may have a substituent. Examples of the substituent include the above-mentioned Ra 05 The same groups as those shown below can be mentioned.

[0045] In the formula (a0-1), Ra 02 and Ra 03 are preferably bonded to each other to form a ring,02 and Ra 03 More preferably, they are bonded to each other to form a monocyclic aliphatic cyclic group.

[0046] In this embodiment, the structural unit (a0) is preferably at least one type selected from the group consisting of structural units represented by general formula (a0-1-1) below and structural units represented by general formula (a0-1-2) below.

[0047] [ka] [In the formula, R 01 , Va01, n a01 and Ra 01 R in the general formula (a0-1) 01 , Va01, n a01 and Ra 01 Same as: Ya 01 is a carbon atom. 01 Ya 01 and R 1 , R 2 , and R 3 form a monocyclic saturated alicyclic hydrocarbon group together. Some or all of the hydrogen atoms in this saturated alicyclic hydrocarbon group may be substituted with a substituent.

[0048] [ka] [In the formula, R 01 , Va01, n a01 and Ra 01 R in the general formula (a0-1) 01 , Va01, n a01 and Ra 01 Same as Ra 021 and Ra 031 are each independently an alkyl group having 1 to 5 carbon atoms.]

[0049] In the formula (a0-1-1), Xa 01 Ya 01 As the monocyclic saturated alicyclic hydrocarbon group formed together with 02 and R 03and 2 are bonded to each other to form a cyclic group, which may be the same as the monocyclic saturated alicyclic hydrocarbon groups exemplified above. Xa 01 Ya 01 The saturated alicyclic hydrocarbon group formed together with Xa may have a substituent. 01 Ya 01 The saturated alicyclic hydrocarbon group formed together with the above may have a substituent, which is preferably selected from the group consisting of the above-mentioned Ra 05 and the like. Among them, Xa 01 Ya 01 The monocyclic saturated alicyclic hydrocarbon group formed together with is preferably a group in which one hydrogen atom has been removed from cyclopentane or cyclohexane.

[0050] In the formula (a0-1-2), Ra 021 and Ra 031 Examples of the alkyl group in Ra 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. 021 and Ra 031 The alkyl group in is preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0051] Specific examples of the structural unit (a0) are shown below. 01 is R in the above formula (a0-1). 01 is the same as:

[0052] [ka]

[0053] [ka]

[0054] The structural unit (a0) contained in the component (A1) may be of one type, or two or more types. The proportion of the structural unit (a0) in the component (A1) is based on the total (100 mol %) of all structural units constituting the component (A1). 58 to 80 mol% and 58 to 75 mol% is preferred, 58 to 70 mol% is more preferred. By making the proportion of the structural unit (a0) at least the lower limit of the above range, lithography properties such as improved roughness can be achieved. By making the proportion of the structural unit (a0) at or below the upper limit, a balance with other structural units can be achieved, resulting in good lithography properties such as improved roughness. When the component (A1) is a binary copolymer consisting of a repeating structure of the structural unit (a0) and a structural unit other than the structural unit (a0), the proportion of the structural unit (a0) in the component (A1) is preferably 58 to 75 mol %, and more preferably 58 to 70 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). When the component (A1) is a terpolymer consisting of a repeating structure of the structural unit (a0) and two types of structural units other than the structural unit (a0), the proportion of the structural unit (a0) in the component (A1) is preferably 58 to 65 mol %, and more preferably 58 to 60 mol %, based on the total (100 mol %) of all structural units constituting the component (A1).

[0055] Other structural units The component (A1) may contain other structural units, in addition to the structural unit (a0) described above, as necessary. Examples of other structural units include structural units (a1) containing an acid-decomposable group whose polarity increases under the action of acid (excluding those corresponding to the aforementioned structural unit (a0)); structural units (a2) containing a lactone-containing cyclic group, an -SO2- containing cyclic group, or a carbonate-containing cyclic group; structural units (a3) ​​containing a polar group-containing aliphatic hydrocarbon group; structural units (a4) containing an acid non-dissociable aliphatic cyclic group; structural units (a10) represented by the general formula (a10-1) described below; and structural units (st) derived from styrene or a styrene derivative.

[0056] <Structural unit (a1)> The structural unit (a1) is a structural unit that contains an acid-decomposable group whose polarity increases when acted upon by an acid. The term "acid-decomposable group" refers to a group having acid decomposability in which at least a part of the bonds 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 under the action of an acid include groups that are decomposed by the action of an acid to generate a polar group. Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (-SO3H), etc. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as an "OH-containing polar group") is preferred, a carboxy group or a hydroxyl group is more preferred, and a carboxy group is particularly preferred. More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0057] The term "acid dissociable group" as used herein refers to both (i) a group having acid dissociability in which the bond between the acid dissociable group and an atom adjacent to the acid dissociable group can be cleaved by the action of an acid, and (ii) a group in which a portion of the bond is cleaved by the action of an acid and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid dissociable group and an atom adjacent to the acid dissociable group. 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, and 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, increasing the polarity. As a result, the polarity of the entire (A1) component 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.

[0058] Examples of the acid-dissociable group include those that have been proposed as acid-dissociable groups in base resins for chemically amplified resist compositions. Specific examples of the acid dissociable group that have been proposed for the base resin of the chemically amplified resist composition include the “acetal type acid dissociable group,” “tertiary alkyl ester type acid dissociable group,” and “tertiary alkyloxycarbonyl acid dissociable group,” which are described below.

[0059] 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 an acid-dissociable group represented by the following general formula (a1-r-1) (hereinafter sometimes referred to as an "acetal-type acid-dissociable group").

[0060] [ka] [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.

[0061] In formula (a1-r-1), Ra' 1 and Ra' 2 At least one of these is preferably a hydrogen atom, and both are more preferably hydrogen atoms. Ra' 1 Or Ra' 2 When is an alkyl group, the alkyl group may be the same as the alkyl group exemplified as the substituent that may be bonded to the carbon atom at the α-position in the explanation of the α-substituted acrylic acid ester above, and an alkyl group having 1 to 5 carbon atoms is preferable. Specifically, a linear or branched alkyl group is preferable. More specifically, 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 the like are preferable, and a methyl group or an ethyl group is more preferable, and a methyl group is particularly preferable.

[0062] 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 has 1 to 4 carbon atoms, and further preferably has 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. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0063] The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and is preferably an isopropyl group.

[0064] Ra' 3 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0065] Ra' 3 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The 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, further 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 a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Ra' 3 Specific examples of the aromatic hydrocarbon group in the above include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or 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., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0066] Ra' 3 The cyclic hydrocarbon group in may have a substituent. Examples of the substituent include the above-mentioned Ra 05 The same groups as those shown below can be mentioned.

[0067] Ra' 3 But Ra' 1 , Ra' 2 When it 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, a tetrahydrofuranyl group, etc.

[0068] Tertiary alkyl ester type acid-labile 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-2). Among the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group may be referred to as "tertiary alkyl ester-type acid-dissociable groups" hereinafter for the sake of convenience.

[0069] [ka] [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.

[0070] Ra' 4 Examples of the hydrocarbon group include a linear or branched alkyl group, a linear or cyclic alkenyl group, or a cyclic hydrocarbon group. Ra' 4 The linear or branched alkyl group and the cyclic hydrocarbon group (the monocyclic aliphatic hydrocarbon group, the polycyclic aliphatic hydrocarbon group, and the aromatic hydrocarbon group) in 3 The same can be mentioned. Ra' 4 The chain or cyclic alkenyl group in is preferably an alkenyl group having 2 to 10 carbon atoms. Ra' 5 , Ra' 6 As the hydrocarbon group of Ra' 3 The same can be mentioned.

[0071] Ra' 5 and Ra' 6 and (a1-r2-3) are preferably used. On the other hand, Ra' 4~Ra' 6 When are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0072] [ka] [In formula (a1-r2-1), Ra' 10 Ra' represents an alkyl group having 1 to 10 carbon atoms or a group represented by the following general formula (a1-r2-r1). 11 Is Ra' 10 In formula (a1-r2-2), Ya is a carbon atom. Xa is a group that forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Ra 01 ~Ra 03 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. 01 ~Ra 03 In formula (a1-r2-3), two or more of Ra' may be bonded to each other to form a cyclic structure. 12 and Ra' 13 are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted. 14 is a hydrocarbon group which may have a substituent. * indicates a bond.]

[0073] [ka] [Wherein, Ya 0 is a quaternary carbon atom. 031 , Ra 032 and Ra 033 are each independently a hydrocarbon group which may have a substituent. 031 , Ra032 and Ra 033 At least one of the groups is a hydrocarbon group having at least one polar group.

[0074] In the above formula (a1-r2-1), Ra' 10 The alkyl group having 1 to 10 carbon atoms is represented by Ra' in the formula (a1-r-1). 3 The groups listed as the linear or branched alkyl group of Ra' are preferred. 10 is preferably an alkyl group having 1 to 5 carbon atoms.

[0075] In the above formula (a1-r2-r1), Ya 0 is a quaternary carbon atom. That is, Ya 0 (carbon atom) has four adjacent carbon atoms bonded to it.

[0076] In the above formula (a1-r2-r1), Ra 031 , Ra 032 and Ra 033 Each of Ra is independently a hydrocarbon group which may have a substituent. 031 , Ra 032 and Ra 033 The hydrocarbon groups in each of the above may independently be a linear or branched alkyl group, a linear or cyclic alkenyl group, or a cyclic hydrocarbon group.

[0077] Ra 031 , Ra 032 and Ra 033 In the linear alkyl group, the carbon number is preferably 1 to 5, more preferably 1 to 4, and further preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred. Ra 031 , Ra 032 and Ra 033In the above, the branched alkyl group preferably has a carbon number of 3 to 10, 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, and is preferably an isopropyl group. Ra 031 , Ra 032 and Ra 033 The chain or cyclic alkenyl group in is preferably an alkenyl group having 2 to 10 carbon atoms.

[0078] Ra 031 , Ra 032 and Ra 033 The cyclic hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0079] Ra 031 , Ra 032 and Ra 033The aromatic hydrocarbon group in the above formula (1) is a hydrocarbon group having at least one aromatic ring. The 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 number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom is removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group); a group in which one hydrogen atom is 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 is substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0080] The above Ra 031 , Ra 032 and Ra 033 When the hydrocarbon group represented by the formula (I) is substituted, examples of the substituent include a hydroxy group, a carboxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkoxy group (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc.), an alkyloxycarbonyl group, etc.

[0081] Among the above, Ra 031 , Ra 032 and Ra 033The optionally substituted hydrocarbon group in is preferably a linear or branched alkyl group which may have a substituent, more preferably a linear alkyl group which may have a substituent.

[0082] However, Ra 031 , Ra 032 and Ra 033 At least one of the groups is a hydrocarbon group having at least a polar group. The term "hydrocarbon group having a polar group" includes both a hydrocarbon group in which a methylene group (-CH-) constituting the hydrocarbon group is replaced with a polar group, and a hydrocarbon group in which at least one hydrogen atom constituting the hydrocarbon group is replaced with a polar group. Such a "hydrocarbon group having a polar group" is preferably a functional group represented by the following general formula (a1-p1).

[0083] [ka] [In the formula, Ra 07 represents a divalent hydrocarbon group having 2 to 12 carbon atoms. 08 represents a divalent linking group containing a hetero atom. 06 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. p0 is an integer from 1 to 6.

[0084] In the above formula (a1-p1), Ra 07 represents a divalent hydrocarbon group having 2 to 12 carbon atoms. Ra 07 has 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, further preferably 2 to 4 carbon atoms, and particularly preferably 2 carbon atoms. Ra 07 The hydrocarbon group in is preferably a chain or cyclic aliphatic hydrocarbon group, and more preferably a chain hydrocarbon group. Ra 07Examples of the alkyl group include linear alkanediyl groups such as an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group; a propane-1,2-diyl group, a 1-methylbutane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, and the like. branched alkanediyl groups such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group, and the like; and polycyclic divalent alicyclic hydrocarbon groups such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and the like. Among the above, an alkanediyl group is preferred, and a linear alkanediyl group is more preferred.

[0085] In the above formula (a1-p1), Ra 08 represents a divalent linking group containing a hetero atom. Ra 08 Examples of such groups include -O-, -C(=O)-O-, -C(=O)-, -OC(=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-, -S(=O)2-, -S(=O)2-O-, and the like. Among these, from the viewpoint of solubility in a developer, -O-, -C(=O)-O-, -C(=O)- and -OC(=O)-O- are preferred, with -O- and -C(=O)- being particularly preferred.

[0086] In the above formula (a1-p1), Ra 06 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. Ra 06has 1 to 12 carbon atoms, and from the viewpoint of solubility in a developer, preferably has 1 to 8 carbon atoms, more preferably has 1 to 5 carbon atoms, even more preferably has 1 to 3 carbon atoms, particularly preferably has 1 or 2 carbon atoms, and most preferably has 1 carbon atom.

[0087] Ra 06 The hydrocarbon group in the formula (I) may be a chain hydrocarbon group, a cyclic hydrocarbon group, or a combination of a chain and a cyclic hydrocarbon group. Examples of chain hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl groups.

[0088] The cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl, adamantyl, 2-alkyladamantan-2-yl, 1-(adamantan-1-yl)alkane-1-yl, norbornyl, methylnorbornyl, and isobornyl. Examples of aromatic hydrocarbon groups include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group.

[0089] Ra 06From the viewpoint of solubility in a developer, the alkyl group is preferably a chain hydrocarbon group, more preferably an alkyl group, and even more preferably a linear alkyl group.

[0090] In the above formula (a1-p1), n p0 represents an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0091] Specific examples of the hydrocarbon group having at least a polar group are shown below. In the following formulae, * denotes a quaternary carbon atom (Ya 0 ) is the bond that bonds to the

[0092] [ka]

[0093] In the above formula (a1-r2-r1), Ra 031 , Ra 032 and Ra 033 The number of hydrocarbon groups having at least a polar group is one or more, but may be appropriately determined in consideration of the solubility in a developer when forming a resist pattern. For example, Ra 031 , Ra 032 and Ra 033 It is preferable that the number of the two is one or two, and it is particularly preferable that the number of the two is one.

[0094] The hydrocarbon group having at least a polar group may have a substituent other than the polar group, such as a halogen atom (such as a fluorine atom, a chlorine atom, or a bromine atom) or a halogenated alkyl group having 1 to 5 carbon atoms.

[0095] In formula (a1-r2-1), Ra' 11 (Ra' 10 The aliphatic cyclic group formed together with the carbon atom to which is bonded) is Ra' in formula (a1-r-1). 3 The groups mentioned above as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups.

[0096] 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 such groups include groups in which one or more hydrogen atoms have been further removed from the cyclic monovalent hydrocarbon group (aliphatic hydrocarbon group) in the above formula. The cyclic hydrocarbon group formed by Xa together with Ya may have a substituent. Examples of the substituent include the above-mentioned Ra' 3 Examples of the substituents include those similar to those that the cyclic hydrocarbon group in the above may have. In formula (a1-r2-2), Ra 01 ~Ra 03 In the above 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. Ra 01 ~Ra 03 In the above formula, examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as 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. Ra 01 ~Ra 03 Of these, from the viewpoint of ease of synthesis of the monomer compound from which the structural unit (a1) is derived, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferred, and of these, a hydrogen atom, a methyl group, or an ethyl group is more preferred, with a hydrogen atom being particularly preferred.

[0097] The above Ra 01 ~Ra 03 Examples of the substituents of the chain saturated hydrocarbon group or the cyclic saturated aliphatic hydrocarbon group represented by the formula 05 The same groups as those shown below can be mentioned.

[0098] Ra 01 ~Ra 03 Examples of groups containing a carbon-carbon double bond resulting from 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 of the monomer compound from which the structural unit (a1) is derived, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred.

[0099] In formula (a1-r2-3), Ra' 12 and Ra' 13 Each of Ra' independently represents a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom. 12 and Ra' 13 In the above, the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is 01 ~Ra 03 Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms in the above formula (1) include those in which some or all of the hydrogen atoms in the chain saturated hydrocarbon group may be substituted. Ra' 12 and Ra' 13 Among these, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferable, an alkyl group having 1 to 5 carbon atoms is more preferable, a methyl group or an ethyl group is further preferable, and a methyl group is particularly preferable. The above Ra' 12 and Ra' 13 In the case where the chain saturated hydrocarbon group represented by the formula (I) is substituted, examples of the substituent include the above-mentioned Ra 05 The same groups as those shown below can be mentioned.

[0100] In formula (a1-r2-3), Ra' 14 Ra' is a hydrocarbon group which may have a substituent. 14 The hydrocarbon group in the formula (I) includes a linear or branched alkyl group, or a cyclic hydrocarbon group.

[0101] 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. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0102] Ra' 14 The branched alkyl group in the above formula (I) preferably has a carbon number of 3 to 10, and more preferably 3 to 5. Specific examples thereof include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and is preferably an isopropyl group.

[0103] Ra' 14 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group of a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Ra' 14 Examples of the substituent that may be possessed by Ra include 04 The substituents may be the same as those which may be possessed by the group.

[0104] Ra' in formula (a1-r2-3) 14 When is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in the above formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. Ra' in formula (a1-r2-4)14 When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the above formula (a1-r2-4) may be any one of the 1-position, 2-position, or 9-position of the anthryl group.

[0105] Specific examples of the group represented by formula (a1-r2-1) are shown below.

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] Specific examples of the group represented by formula (a1-r2-2) are shown below.

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] Specific examples of the group represented by formula (a1-r2-3) are shown below.

[0114] [ka]

[0115] Tertiary alkyloxycarbonyl acid dissociating group: Among the polar groups, examples of the acid dissociable group that protects the hydroxyl 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").

[0116] [ka] [In the formula, Ra' 7 ~Ra' 9 are each an alkyl group.

[0117] In formula (a1-r-3), Ra' 7 ~Ra' 9 is preferably an alkyl group having 1 to 5 carbon atoms, and 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.

[0118] 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 an acrylamide, a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least a portion 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 a portion of the hydrogen atoms in -C(═O)-OH are protected with a substituent containing the above-mentioned acid-decomposable group.

[0119] 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 carbon atom at the α-position may be substituted with a substituent. Preferred specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1) or (a1-2).

[0120] [ka] [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) or (a1-r-2). 1 is a2 +1-valent hydrocarbon group, n a2 is an integer from 1 to 3, and Ra 2 is an acid dissociable group represented by the above general formula (a1-r-1).

[0121] In the formula (a1-1), the alkyl group of R 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 are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is most preferable.

[0122] In the formula (a1-1), Va 1 The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0123] Va 1 The aliphatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in the structure.

[0124] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably has 1 to 6 carbon atoms, further preferably has 1 to 4 carbon atoms, and most preferably has 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)5-], etc. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, even more preferably has 3 or 4 carbon atoms, and most preferably has 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0125] Examples of the aliphatic hydrocarbon group containing a ring in the structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group, etc. 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, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. 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 obtained by removing two hydrogen atoms from a polycycloalkane, specifically cycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0126] Va 1 The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such an aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this carbon number does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (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 (aryl group) has been substituted with an alkylene group (for example, a group in which one hydrogen atom has been further removed from the aryl group in 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 to 2, and particularly preferably 1.

[0127] In the formula (a1-1), Ra 1 is an acid-dissociable group represented by the above formula (a1-r-1) or (a1-r-2).

[0128] In the formula (a1-2), Wa 1 n in a2 The +1-valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, and is usually preferably saturated. The aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in its structure, or a group that combines a straight-chain or branched-chain aliphatic hydrocarbon group with an aliphatic hydrocarbon group containing a ring in its structure. The above n a2 The +1 valency is preferably 2 to 4, more preferably 2 or 3.

[0129] In the formula (a1-2), Ra 2 is an acid dissociable group represented by the above general formula (a1-r-1).

[0130] Specific examples of the structural unit represented by the formula (a1-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] Specific examples of the structural unit represented by formula (a1-2) are shown below.

[0142] [ka]

[0143] The structural unit (a1) contained in the component (A1) may be of one type, or two or more types. As the structural unit (a1), a structural unit represented by the above formula (a1-1) is more preferable, since it is easier to improve the characteristics (sensitivity, shape, etc.) in electron beam or EUV lithography. Among these, as the structural unit (a1), those containing a structural unit represented by general formula (a1-1-1) shown below are particularly preferable.

[0144] [ka] [In the formula, Ra 1 " is an acid-dissociable group represented by general formula (a1-r2-1) or (a1-r2-4).

[0145] In the formula (a1-1-1), R and Va 1 and n a1 R and Va in the formula (a1-1) 1 and n a1 is the same as: The acid dissociable group represented by formula (a1-r2-1) or (a1-r2-4) is as described above. Among them, it is preferable to select the acid dissociable group as a cyclic group, since it is suitable for EB or EUV use in that reactivity can be increased.

[0146] The proportion of the structural unit (a1) in the component (A1) relative to the total (100 mol%) of all structural units constituting the component (A1), is preferably from 5 to 60 mol%, more preferably from 10 to 60 mol%, even more preferably from 10 to 55 mol%, and particularly preferably from 15 to 25 mol%. By ensuring that the proportion of the structural unit (a1) is at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity, resolution, and roughness can be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0147] Regarding the structural unit (a2): The component (A1) may further contain, in addition to the structural unit (a1), a structural unit (a2) containing a lactone-containing cyclic group, an -SO2- containing cyclic group, or a carbonate-containing cyclic group (provided that this does not correspond to the structural unit (a1)). The lactone-containing cyclic group, -SO2--containing cyclic group, or carbonate-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate when the component (A1) is used to form a resist film. In addition, the structural unit (a2) has the effects of, for example, appropriately adjusting the acid diffusion length, improving the adhesion of the resist film to the substrate, and appropriately adjusting the solubility during development, thereby improving the lithography properties, etc.

[0148] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) containing -OC(=O)- in 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 further a 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. The lactone-containing cyclic group in the structural unit (a2) is not particularly limited and any suitable group can be used. Specific examples include the groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0149] [ka] [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, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO2- 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.

[0150] In the general formulas (a2-r-1) to (a2-r-7), Ra' 21 The alkyl group in 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. Among 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, the formula (1) is preferably a linear or branched alkoxy group. 21 Examples of the alkyl group include those groups in which the alkyl groups mentioned above are linked to an oxygen atom (-O-). Ra' 21 Examples of the halogen atom in include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable. Ra' 21 As the halogenated alkyl group in the above, Ra' 21 and groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the above halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0151] Ra' 21In -COOR" and -OC(=O)R", R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO2- containing cyclic group. The alkyl group in 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 4 to 12 carbon atoms, and most preferably 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; groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples of the lactone-containing cyclic group in R″ include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7) above. The carbonate-containing cyclic group in R″ is the same as the carbonate-containing cyclic group described later, and specific examples thereof include groups represented by general formulae (ax3-r-1) to (ax3-r-3). The -SO2-containing cyclic group in R'' is the same as the -SO2-containing cyclic group described later, and specific examples thereof include the groups represented by general formulas (a5-r-1) to (a5-r-4). Ra' 21 The hydroxyalkyl group in Ra' is preferably one having 1 to 6 carbon atoms. 21 In the above formula, at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0152] In the general formulae (a2-r-2), (a2-r-3) and (a2-r-5), the alkylene group having 1 to 5 carbon atoms in 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 the carbon atoms of the alkylene group, and examples thereof include O-CH2-, -CH2-O-CH2-, -S-CH2- and -CH2-S-CH2-. 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.

[0153] Specific examples of the groups represented by general formulas (a2-r-1) to (a2-r-7) are listed below.

[0154] [ka]

[0155] [ka]

[0156] The term "-SO2-containing cyclic group" refers to a cyclic group containing a ring containing -SO2- in its ring structure, specifically, a cyclic group in which the sulfur atom (S) in -SO2- forms a part of the ring structure of the cyclic group. The ring containing -SO2- in the ring structure is counted as the first ring, and if there is only this ring, it is called a monocyclic group, and if there is another ring structure, it is called a polycyclic group regardless of the structure. The -SO2-containing cyclic group may be a monocyclic group or a polycyclic group. The -SO2- containing cyclic group is preferably a cyclic group containing -O-SO2- in its ring skeleton, that is, a cyclic group containing a sultone ring in which -OS- in -O-SO2- forms a part of the ring skeleton. More specific examples of the -SO2- containing cyclic group include groups represented by the following general formulas (a5-r-1) to (a5-r-4).

[0157] [ka] [In the formula, Ra' 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, a carbonate-containing cyclic group, or a -SO2- containing cyclic group; A" 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, and n' is an integer of 0 to 2.

[0158] In the general formulae (a5-r-1) and (a5-r-2), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3) and (a2-r-5). Ra' 51 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each represented by Ra' 21 Examples of the above-mentioned are similar to those mentioned in the explanation of the above. Specific examples of the groups represented by general formulas (a5-r-1) to (a5-r-4) are shown below, in which "Ac" represents an acetyl group.

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] The term "carbonate-containing cyclic group" refers to a cyclic group that contains a ring (carbonate ring) containing -OC(=O)-O- in its ring skeleton. The carbonate ring is counted as the first ring, and when there is only a carbonate ring, it is called a monocyclic group, and when there is another ring structure, it is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group. The carbonate ring-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following general formulae (ax3-r-1) to (ax3-r-3).

[0163] [ka] [In the formula, Ra' x31 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, a carbonate-containing cyclic group, or a -SO2- containing cyclic group; A" 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, p' is an integer of 0 to 3, and q' is 0 or 1.

[0164] In the general formulae (ax3-r-2) to (ax3-r-3), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3) and (a2-r-5). Ra' 31 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each represented by Ra' 21 Examples of the above-mentioned are similar to those mentioned in the explanation of the above. Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are listed below.

[0165] [ka]

[0166] Of the various possibilities, the structural unit (a2) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The structural unit (a2) is preferably a structural unit represented by the following general formula (a2-1).

[0167] [ka] [In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 21 is a single bond or a divalent linking group. 21 is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO-, or -CONHCS-, where R' represents a hydrogen atom or a methyl group. 21 If -O-, Ya 21 does not become -CO-. Ra 21 is a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO2- containing cyclic group.

[0168] 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 preferable.

[0169] 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.

[0170] Optionally substituted divalent hydrocarbon group: Ya 21When is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0171] Ya 21 Aliphatic hydrocarbon groups in The aliphatic hydrocarbon group means a hydrocarbon group having no 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.

[0172] Linear or branched aliphatic hydrocarbon groups The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably has 1 to 6 carbon atoms, further preferably has 1 to 4 carbon atoms, and most preferably has 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)5-], etc. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, even more preferably has 3 or 4 carbon atoms, and most preferably has 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0173] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, which may include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and a carbonyl group.

[0174] Aliphatic hydrocarbon groups containing rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0175] The cyclic aliphatic hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or 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, 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 further 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, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include the alkyl groups in which some or all of the hydrogen atoms of the alkyl groups are substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0176] Ya 21 Aromatic hydrocarbon groups in The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The 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 number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); a group in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); a group 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., a group in which one hydrogen atom has been further removed from the aryl group in 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 bonded to the aryl group or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0177] 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 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.

[0178] Divalent linking groups containing heteroatoms: Ya 21 is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=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-, -S(=O)2-, -S(=O)2-O-, and a divalent linking group containing a hetero atom, 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or-Y 21 -S(=O)2-OY 22 -, wherein Y 21 and Y 22 each independently represents a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 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, an acyl group, etc. 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. General formula-Y 21 -OY22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or-Y 21 -S(=O)2-OY 22 -Medium, Y 21 and Y 22 Each of the Ya independently represents a divalent hydrocarbon group which may have a substituent. 21 Examples of the divalent linking group in the above formula (divalent hydrocarbon group which may have a substituent) include those similar to those mentioned in the above formula (divalent linking group which may have a substituent). Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferable, a straight-chain alkylene group is more preferable, a straight-chain alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or ethylene group is particularly preferable. Y 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. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22 The group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) 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, still 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, still more preferably 1 or 2, and most preferably 1.

[0179] Among the above, 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.

[0180] In the above formula (a2-1), Ra 21 is a lactone-containing cyclic group, an -SO2- containing cyclic group, or a carbonate-containing cyclic group. Ra 21 Suitable examples of the lactone-containing cyclic group, the -SO2- containing cyclic group and the carbonate-containing cyclic group in the above formula (a2-r-1) to (a2-r-7), the groups represented by the general formulas (a5-r-1) to (a5-r-4) and the groups represented by the general formulas (ax3-r-1) to (ax3-r-3) are respectively. Among them, lactone-containing cyclic groups or -SO2-containing cyclic groups are preferred, and the groups represented by the general formulae (a2-r-1), (a2-r-2), (a2-r-6) and (a5-r-1) are more preferred. Specifically, any of the groups represented by the chemical formulae (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1) and (r-sl-1-18) are more preferred.

[0181] The structural unit (a2) contained in the component (A1) may be of one type, or two or more types. When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) relative to the total (100 mol%) of all structural units constituting the component (A1) is preferably 5 to 60 mol%, more preferably 10 to 60 mol%, even more preferably 10 to 55 mol%, and particularly preferably 15 to 25 mol%. When the proportion of the structural unit (a2) is at least as large as the preferred lower limit, the effects achieved by including the structural unit (a2) as described above can be fully obtained. When the proportion of the structural unit (a2) is at most the upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0182] Regarding the structural unit (a3): In addition to the structural unit (a1), the component (A1) may further include a structural unit (a3) ​​(excluding those corresponding to the structural unit (a1) or the structural unit (a2)) that contains a polar group-containing aliphatic hydrocarbon group. When the component (A1) includes the structural unit (a3), the hydrophilicity of the component (A) is increased, which contributes to improving the resolution. In addition, the acid diffusion length can be appropriately adjusted.

[0183] Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which some of the hydrogen atoms of an alkyl group are substituted with fluorine atoms, with a hydroxyl group being particularly preferred. Examples of the aliphatic hydrocarbon group include linear or branched hydrocarbon groups (preferably alkylene groups) having 1 to 10 carbon atoms, and cyclic aliphatic hydrocarbon groups (cyclic groups). The cyclic group may be a monocyclic group or a polycyclic group, and can be appropriately selected from the many groups proposed for use in resins for resist compositions for ArF excimer lasers.

[0184] When the cyclic group is a monocyclic group, the number of carbon atoms is more preferably 3 to 10. Among them, a structural unit derived from an acrylic acid ester containing an aliphatic monocyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which a portion of the hydrogen atoms of the alkyl group is substituted with a fluorine atom is more preferred. Examples of the monocyclic group include groups in which two or more hydrogen atoms have been removed from a monocycloalkane. Specific examples include groups in which two or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane, cyclohexane, and cyclooctane. Among these monocyclic groups, groups in which two or more hydrogen atoms have been removed from cyclopentane and groups in which two or more hydrogen atoms have been removed from cyclohexane are industrially preferred.

[0185] When the cyclic group is a polycyclic group, the number of carbon atoms of the polycyclic group is more preferably 7 to 30. Among them, a structural unit derived from an acrylic acid ester containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which a portion of the hydrogen atoms of the alkyl group is substituted with a fluorine atom is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from a bicycloalkane, a tricycloalkane, a tetracycloalkane, etc. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane are industrially preferred.

[0186] There are no particular limitations on the structural unit (a3), and any structural unit can be used as long as it contains a polar group-containing aliphatic hydrocarbon group. The structural unit (a3) ​​is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and which contains a polar group-containing aliphatic hydrocarbon group. As the structural unit (a3), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a straight-chain or branched-chain hydrocarbon group having 1 to 10 carbon atoms, a structural unit derived from a hydroxyethyl ester of acrylic acid is preferred. Furthermore, when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a polycyclic group, preferred examples of the structural unit (a3) ​​include structural units represented by the following formulae (a3-1), (a3-2), and (a3-3); when the hydrocarbon group is a monocyclic group, preferred examples of the structural unit (a3) ​​include structural units represented by formula (a3-4).

[0187] [ka] [In the formula, R is the same as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t' is an integer of 1 to 3, l is an integer of 0 to 5, and s is an integer of 1 to 3.]

[0188] In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3rd position of the adamantyl group. It is preferable that j is 1, and it is particularly preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.

[0189] In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5- or 6-position of the norbornyl group.

[0190] In formula (a3-3), t' is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxyl group of the acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5- or 6-position of the norbornyl group.

[0191] In formula (a3-4), t' is preferably 1 or 2. l is preferably 0 or 1. s is preferably 1. The fluorinated alkyl alcohol is preferably bonded to the 3- or 5-position of the cyclohexyl group.

[0192] The structural unit (a3) ​​contained in the component (A1) may be of one type, or two or more types. When the component (A1) contains the structural unit (a3), the proportion of the structural unit (a3) ​​relative to the total (100 mol %) of all structural units constituting the component (A1) is preferably 1 to 30 mol %, more preferably 2 to 25 mol %, and even more preferably 5 to 20 mol %. By ensuring that the proportion of the structural unit (a3) ​​is at least as large as the preferred lower limit, the effects described above can be fully achieved by including the structural unit (a3). By ensuring that the proportion of the structural unit (a3) ​​is at most the preferred upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0193] Regarding the structural unit (a4): The component (A1) may further contain, in addition to the structural unit (a1), a structural unit (a4) that contains an acid non-dissociable aliphatic cyclic group. By including the structural unit (a4) in the component (A1), the dry etching resistance of the formed resist pattern is improved. In addition, the hydrophobicity of the component (A) is enhanced. The improved hydrophobicity contributes to improvements in the resolution, resist pattern shape, etc., particularly in the case of a solvent development process. The “acid non-dissociable cyclic group” within the structural unit (a4) is a cyclic group that, when acid is generated in the resist composition upon exposure (for example, when acid is generated from a structural unit that generates acid upon exposure or from the component (B)), does not dissociate even when acted upon by the acid, and remains as is within the structural unit.

[0194] The structural unit (a4) is preferably, for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic cyclic group. The cyclic group can be any of a large number of conventionally known resin components for resist compositions for ArF excimer lasers, KrF excimer lasers (preferably ArF excimer lasers), etc. The cyclic group is preferably at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group, in view of industrial availability, etc. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent. Specific examples of the structural unit (a4) include the structural units represented by the following general formulas (a4-1) to (a4-7).

[0195] [ka] [In the formula, R α is the same as above.]

[0196] The structural unit (a4) contained in the component (A1) may be of one type, or two or more types. When the component (A1) contains the structural unit (a4), the proportion of the structural unit (a4) is preferably 1 to 40 mol %, and more preferably 5 to 20 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a4) is at least as large as the preferred lower limit, the effects of including the structural unit (a4) can be fully obtained, while by ensuring that the proportion is no more than the preferred upper limit, it becomes easier to achieve a balance with other structural units.

[0197] Regarding the structural unit (a10): The structural unit (a10) is a structural unit represented by general formula (a10-1) shown below.

[0198] [ka] [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 greater than or equal to 1.

[0199] In the above formula (a10-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. The alkyl group having 1 to 5 carbon atoms for 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 in R is a group in which some or all of the hydrogen atoms in the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. 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, more preferably a hydrogen atom, a methyl group, or a trifluoromethyl group, still more preferably a hydrogen atom or a methyl group, and particularly preferably a methyl group.

[0200] In the formula (a10-1), Ya x1 is a single bond or a divalent linking group. In the above chemical formula, Ya 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.

[0201] Optionally substituted divalent hydrocarbon group: Ya x1When is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0202] Ya x1 Aliphatic hydrocarbon groups in The aliphatic hydrocarbon group means a hydrocarbon group having no 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.

[0203] Linear or branched aliphatic hydrocarbon groups 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 straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)5-], etc. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, even more preferably has 3 or 4 carbon atoms, and most preferably has 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0204] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, which may include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and a carbonyl group.

[0205] Aliphatic hydrocarbon groups containing rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0206] The cyclic aliphatic hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or 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, 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 further 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, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include the alkyl groups in which some or all of the hydrogen atoms of the alkyl groups are substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0207] Ya x1 Aromatic hydrocarbon groups in The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The 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 number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); a group in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); a group 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., a group in which one hydrogen atom has been further removed from the aryl group in 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 bonded to the aryl group or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0208] 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 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.

[0209] Divalent linking groups containing heteroatoms: Ya x1 is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=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-, -S(=O)2-, -S(=O)2-O-, and a divalent linking group containing a hetero atom, 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or-Y 21 -S(=O)2-OY 22 -, wherein Y 21 and Y 22 each independently represents a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 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, acyl, etc. 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. General formula-Y 21 -OY22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or-Y 21 -S(=O)2-OY 22 -Medium, Y 21 and Y 22 Each of the Ya independently represents a divalent hydrocarbon group which may have a substituent. x1 Examples of the divalent linking group in the above formula (divalent hydrocarbon group which may have a substituent) include those similar to those mentioned in the above formula (divalent linking group which may have a substituent). Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferable, a straight-chain alkylene group is more preferable, a straight-chain alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or ethylene group is particularly preferable. Y 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. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22 The group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) 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, still 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, still more preferably 1 or 2, and most preferably 1.

[0210] Among the above, Ya x1 is preferably a single bond, an ester bond [-C(=O)-O-, -OC(=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-, -OC(=O)-].

[0211] In the formula (a10-1), Wa x1 is an aromatic hydrocarbon group which may have a substituent. Wa x1 The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ax1 4n+1) hydrogen atoms are removed. The aromatic ring here 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, further 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 a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Also, Wa x1 The aromatic hydrocarbon group in the formula (n) may be an aromatic compound having an aromatic ring which may have two or more substituents (e.g., biphenyl, fluorene, etc.). ax1 +1) hydrogen atoms may also be removed. Among the above, Wa x1As the aryl group, benzene, naphthalene, anthracene, or biphenyl (n ax1 A group in which (n +1) hydrogen atoms have been removed is preferred, and a group in which (n ax1 A group in which (n +1) hydrogen atoms have been removed from benzene is more preferable. ax1 A group in which +1) hydrogen atoms have been removed is more preferred.

[0212] 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, the alkoxy group, the halogen atom, and the halogenated alkyl group as the substituent include Ya x1 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.

[0213] 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, further preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0214] Specific examples of the structural unit (a10) represented by the aforementioned formula (a10-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0215] [ka]

[0216] [ka]

[0217] [ka]

[0218] [ka]

[0219] The structural unit (a10) contained in the component (A1) may be of one type, or two or more types. When the component (A1) contains the structural unit (a10), the proportion of the structural unit (a10) in the component (A1) is preferably 5 to 50 mol %, more preferably 5 to 40 mol %, and even more preferably 10 to 30 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a10) is at least as large as the lower limit of the above range, it is possible to further increase the sensitivity, whereas by ensuring that the proportion is at most the upper limit of the above range, it is easier to achieve a balance with other structural units.

[0220] Regarding the structural unit (st): The structural unit (st) is a structural unit derived from styrene or a styrene derivative. A "structural unit derived from styrene" refers to a structural unit formed by cleavage of the ethylenic double bond of styrene. A "structural unit derived from a styrene derivative" refers to a structural unit formed by cleavage of the ethylenic double bond of a styrene derivative (however, this does not include those that fall under the structural unit (a10)).

[0221] The term "styrene derivative" refers to a compound in which at least some of the hydrogen atoms of styrene are substituted with a substituent. Examples of styrene derivatives include those in which the hydrogen atom at the α-position of styrene is substituted with a substituent, those in which one or more hydrogen atoms on the benzene ring of styrene are substituted with a substituent, and those in which the hydrogen atom at the α-position of styrene and one or more hydrogen atoms on the benzene ring are substituted with a substituent.

[0222] Examples of the substituent substituting the hydrogen atom at the α-position of styrene include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms. 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 are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. The substituent substituting the hydrogen atom at the α-position of styrene is preferably an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms or a fluorinated alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group from the viewpoint of industrial availability.

[0223] Examples of the substituent that substitutes the hydrogen atom on the benzene ring of styrene include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl 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, 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 further 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, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include the alkyl groups in which some or all of the hydrogen atoms of the alkyl groups are substituted with the halogen atoms. The substituent that substitutes the hydrogen atom on the benzene ring of styrene is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0224] The structural unit (st) is preferably a structural unit derived from styrene, or a structural unit derived from a styrene derivative in which the hydrogen atom at the α-position of styrene is substituted with an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, more preferably a structural unit derived from styrene, or a structural unit derived from a styrene derivative in which the hydrogen atom at the α-position of styrene is substituted with a methyl group, and even more preferably a structural unit derived from styrene.

[0225] The structural unit (st) contained in the component (A1) may be of one type, or two or more types. When the component (A1) contains the structural unit (st), the proportion of the structural unit (st) is preferably 1 to 30 mol %, and more preferably 3 to 20 mol %, based on the total (100 mol %) of all structural units constituting the component (A1).

[0226] The component (A1) contained in the resist composition may use either a single type of compound, or a combination of two or more types of compounds. In the resist composition of this embodiment, the component (A1) can be a polymeric compound that has a repeating structure of the structural unit (a0). Preferred examples of the component (A1) include polymeric compounds having a repeating structure of the structural unit (a0) and the structural unit (a10); and polymeric compounds having a repeating structure of the structural unit (a0), the structural unit (a10), and the structural unit (a2).

[0227] The (A1) component can be produced by dissolving 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 (a1) and, if necessary, a monomer that derives a structural unit other than the structural unit (a1) in a polymerization solvent, adding the above-mentioned radical polymerization initiator to the resulting solution to polymerize, and then carrying out a deprotection reaction. In addition, during polymerization, a chain transfer agent such as HS-CH2-CH2-CH2-C(CF3)2-OH may be used in combination to introduce a -C(CF3)2-OH group to the end. In this way, a copolymer having a hydroxyalkyl group in which some of the hydrogen atoms of the alkyl group are replaced with fluorine atoms is introduced, which is effective in reducing development defects and LER (line edge roughness: unevenness of the line sidewall).

[0228] The weight average molecular weight (Mw) of the component (A1) (based on polystyrene conversion by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, even more preferably 3,000 to 20,000, and even more preferably 3,500 to 85,000. When the Mw of the component (A1) is no more than the preferred upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is no less than the preferred lower limit of this range, the dry etching resistance and cross-sectional shape of the resist pattern are excellent. The dispersity (Mw / Mn) of the component (A1) is not particularly limited and is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.0, even more preferably from 1.0 to 2.0, and still more preferably from 1.3 to 1.65, where Mn represents the number average molecular weight.

[0229] Base components other than component (A1) The resist composition of this embodiment may use, as the component (A), a base component other than the component (A1) whose solubility in a developer changes under the action of an acid. The base component other than the component (A1) is not particularly limited and may be arbitrarily selected from the many base components conventionally known for use in chemically amplified resist compositions, and may be a single polymeric or low molecular compound, or a combination of two or more polymeric or low molecular compounds.

[0230] 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.

[0231] <Other ingredients> The resist composition of this embodiment may further contain other components in addition to the above-mentioned component (A). Examples of other components include the following components (B), (D), (E), (F), and (S).

[0232] <Acid generator component (B)> The resist composition of this embodiment may further contain, in addition to the component (A), an acid generator component (B) (hereafter referred to as “component (B)”) that generates acid upon exposure. There are no particular limitations on the component (B), and any of the compounds 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 bisarylsulfonyl diazomethanes and poly(bissulfonyl) diazomethanes, nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators.

[0233] Examples of the onium salt-based 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)").

[0234] [ka] [In the formula, R 101 and R 104 ~R 108 R each independently 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. 104 and R 105 R may be bonded to each other to form a ring structure. 102 Y is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 101 is a divalent linking group containing an oxygen atom or a single bond. 101 ~V 103 Each of L is independently a single bond, an alkylene group, or a fluorinated alkylene group. 101 ~L 102 Each of L is independently a single bond or an oxygen atom. 103 ~L 105 are each independently a single bond, -CO- or -SO2-. m is an integer of 1 or more, and M' m+ is an onium cation with a valence of m.

[0235] {anion part} Anion in component (b-1) In formula (b-1), R 101 represents an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0236] Optionally substituted cyclic groups: 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 that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0237] R 101 The aromatic hydrocarbon group in the formula (I) 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, further 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. R 101 Specific examples of the aromatic ring of the aromatic hydrocarbon group in the above formula 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, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R 101 Specific examples of the aromatic hydrocarbon group in the above include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl 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 to 2, and particularly preferably 1.

[0238] R 101 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in 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 straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is present in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among them, the polycycloalkane is more preferably a polycycloalkane having a polycyclic skeleton of a bridged ring system, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton.

[0239] Among them, R 101 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or 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.

[0240] The linear aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has a carbon number of 1 to 10, more preferably 1 to 6, further preferably 1 to 4, and most preferably 1 to 3. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)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 preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0241] Also, R 101 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7), -SO2--containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4), and heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16). * in the formula represents Y in formula (b-1). 101 Represents a bond that bonds to .

[0242] [ka]

[0243] R 101 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as 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 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. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being preferred. 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 above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[0244] 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 polycyclic skeleton of a bridged ring system to which one or more aromatic rings are fused. Specific examples of the bridged ring system 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 the formula (b-1) include those represented by the following formulas (r-br-1) to (r-br-2). 101 Represents a bond that bonds to .

[0245] [ka]

[0246] R 101 Examples 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, and an alicyclic hydrocarbon group. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group are defined as R 101 Examples of the substituents of the cyclic group in the above formula (I) include the same as those exemplified as the substituents of the cyclic group in the above formula (I). Examples of the aromatic hydrocarbon group as the substituent of the fused ring group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc.), and the 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 groups obtained by removing one hydrogen atom from a monocycloalkane such as cyclopentane or cyclohexane; groups obtained by removing one hydrogen atom from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane; lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above; -SO2- containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above; and heterocyclic groups represented by the formulae (r-hr-7) to (r-hr-16) above.

[0247] Optionally substituted chain alkyl groups: R 101 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. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group, and a docosyl group. 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.

[0248] An optionally substituted chain alkenyl group: 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, further 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 butynyl 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, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0249] R 101Examples 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 above-mentioned R 101 and the like.

[0250] Among the above, R 101 is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, preferred are 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), and an -SO2--containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4).

[0251] In formula (b-1), Y 101 is a single bond or a divalent linking group containing an oxygen atom. Y 101 When Y is a divalent linking group containing an oxygen atom, 101 may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms. Examples of the divalent linking group containing an oxygen atom 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 (-OC(=O)-), an amide bond (-C(=O)-NH-), a carbonyl group (-C(=O)-), and a carbonate bond (-OC(=O)-O-); and combinations of the non-hydrocarbon oxygen atom-containing linking groups and alkylene groups. A sulfonyl group (-SO2-) may be further linked to this combination. Examples of the divalent linking group containing an oxygen atom include linking groups represented by the following general formulas (y-al-1) to (y-al-7).

[0252] [ka] [In the formula, V' 101is 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.

[0253] 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.

[0254] V' 101 and V' 102 The alkylene group in may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102 Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 In the above 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 above formula (a1-r-1). 3A divalent group in which one hydrogen atom has been further removed from a cyclic aliphatic hydrocarbon group (a monocyclic aliphatic hydrocarbon group, a polycyclic aliphatic hydrocarbon group) such as those mentioned above is preferred, and a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group is more preferred.

[0255] Y 101 As the linking group, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, and the linking groups represented by the above formulas (y-al-1) to (y-al-5) are more preferable.

[0256] In formula (b-1), V 101 is a single bond, an alkylene group or a fluorinated alkylene group. 101 The alkylene group and fluorinated alkylene group in the formula (I) preferably have 1 to 4 carbon atoms. 101 The fluorinated alkylene group in 101 In particular, the alkylene group represented by the formula (I) is preferably a group in which some or all of the hydrogen atoms of the alkylene group are substituted with fluorine atoms. 101 is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

[0257] In formula (b-1), R 102 R 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.

[0258] 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 anions include those represented by any of the following formulas (an-1) to (an-3).

[0259] [ka] [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-6), a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), or a chain alkyl group which may have a substituent. 102 R" is an aliphatic cyclic group which may have a substituent, a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1), (a2-r-3) to (a2-r-7), or an -SO2- containing cyclic group represented by each of the above general formulas (a5-r-1) to (a5-r-4). 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 R is a single bond, an alkylene group having 1 to 4 carbon atoms, or a fluorinated alkylene group having 1 to 4 carbon atoms. 102 is 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.

[0260] R” 101 , R.” 102 and R.” 103 The aliphatic cyclic group which may have a substituent is represented by R 101 As the substituent, R in the formula (b-1) is preferably a group exemplified as the cyclic aliphatic hydrocarbon group. 101 Examples of the substituents which may substitute the cyclic aliphatic hydrocarbon group in the above formula (1) include the same as those in the above formula (1).

[0261] R” 103 The aromatic cyclic group which may have a substituent in the formula (b-1) is 101 The substituent is preferably a group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in the formula (b-1). 101The substituents which may substitute the aromatic hydrocarbon group in the above formula (I) are the same as those in the above formula (I).

[0262] R” 101 The chain alkyl group which may have a substituent in the formula (b-1) is R 101 The alkyl group is preferably one of the groups exemplified as the chain alkyl group in the above formula (I). R” 103 The chain alkenyl group which may have a substituent is represented by R 101 Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0263] Anion in component (b-2) In formula (b-2), R 104 , R 105 each independently 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 represents R 101 However, R 104 , R 105 may be bonded to each other to form a ring. R 104 , R 105 is preferably a chain alkyl group which may have a substituent, and more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and further preferably 1 to 3 carbon atoms. 104 , R 105 The number of carbon atoms in the chain-like alkyl group of R is preferably as small as possible within the above range of carbon numbers, for reasons such as good solubility in a resist solvent. 104 , R 105In the chain alkyl group, the more hydrogen atoms substituted with fluorine atoms, the stronger the acid strength becomes, and the more the transparency to high-energy light of 250 nm or less and electron beams improves, which is preferable. The ratio 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 each independently represents a single bond, an alkylene group, or a fluorinated alkylene group, and each represents V in formula (b-1). 101 The same can be mentioned. In formula (b-2), L 101 , L 102 are each independently a single bond or an oxygen atom.

[0264] Anion in component (b-3) In formula (b-3), R 106 ~R 108 each independently 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 represents R 101 The same can be mentioned. In formula (b-3), L 103 ~L 105 are each independently a single bond, -CO- or -SO2-.

[0265] Among the above, the anion moiety of the (B) component is preferably the anion in the (b-1) component, more preferably the anion represented by any one of the above general formulae (an-1) to (an-3), further preferably the anion represented by any one of the general formulae (an-1) or (an-2), and particularly preferably the anion represented by the general formula (an-2).

[0266] {cationic part} In the above formula (b-1), formula (b-2), and formula (b-3), M' m+represents an onium cation having a valence of m. Among these, a sulfonium cation and an iodonium cation are preferred. m is an integer of 1 or greater.

[0267] Preferred cationic moieties ((M' m+ ) 1 / m ) include organic cations represented by the following general formulas (ca-1) to (ca-4), respectively.

[0268] [ka] [In the formula, R 201 ~R 207 , and R 211 ~R 212 R each independently represents an aryl group, an alkyl group, or an alkenyl group which may have a substituent. 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 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 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-. 201 each independently represents an arylene group, an alkylene group, or an alkenylene group; x is 1 or 2. W 201 represents a (x+1)-valent linking group.

[0269] In the above general formulas (ca-1) to (ca-4), R 201 ~R 207 , and R 211 ~R 212 The aryl group in may be an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 , and R 211 ~R 212 The alkyl group in is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 , and R 211 ~R 212 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 , and R 210 ~R 212 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulas (ca-r-1) to (ca-r-7).

[0270] [ka] [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.

[0271] Optionally substituted cyclic groups: 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 that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0272] R' 201The aromatic hydrocarbon group in the formula (I) 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, further preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, the carbon number does not include the carbon number of the substituent. R' 201 Specific examples of the aromatic ring of the aromatic hydrocarbon group in the above formula 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, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201 Specific examples of the aromatic hydrocarbon group in the above include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl 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 to 2, and particularly preferably 1.

[0273] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in 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 straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is present in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among them, the polycycloalkane is more preferably a polycycloalkane having a polycyclic skeleton of a bridged ring system, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton.

[0274] Among them, R' 201 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or 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.

[0275] 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, further preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], a pentamethylene group [-(CH2)5-], etc. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specific examples thereof include alkyl alkylene groups such as alkyl methylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, -C(CH2CH3)2-, etc.; alkyl ethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2-, etc.; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0276] Also, R' 201 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include the lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above, the -SO2- containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above, and the heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) above.

[0277] R' 201 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as 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 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. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being preferred. 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 above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[0278] Optionally substituted chain alkyl groups: 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 has 1 to 15 carbon atoms, and most preferably has 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group, and a docosyl group. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably has 3 to 15 carbon atoms, and most preferably has 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.

[0279] An optionally substituted chain alkenyl group: 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, further preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl 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, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0280] 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 R' 201 and the like.

[0281] R' 201 In addition to the above-mentioned, the optionally substituted cyclic group, the optionally substituted chain alkyl group, or the optionally substituted chain alkenyl group also includes the same as the acid-dissociable group represented by formula (a1-r-2) above as the optionally substituted cyclic group or the optionally substituted chain alkyl group.

[0282] 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), and an -SO2--containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4) are preferred.

[0283] In the above general formulas (ca-1) to (ca-4), R 201 ~R203 , R 206 ~R 207 , R 211 ~R 212 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they do not include a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, a carbonyl group, -SO-, -SO2-, -SO3-, -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, in which a ring containing a sulfur atom in the ring skeleton in the formula is a 3- to 10-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene 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.

[0284] 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.

[0285] R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in may be an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 210As the -SO2- containing cyclic group which may have a substituent in the above formula (a5-r-1), an "-SO2- containing polycyclic group" is preferable, and a group represented by the above formula (a5-r-1) is more preferable.

[0286] Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. Y 201 The arylene group in the above formula (b-1) is 101 Examples of the aromatic hydrocarbon group in the above formula include groups in which one hydrogen atom has been removed from the aryl groups exemplified above. Y 201 The alkylene group and alkenylene group in the above formula (b-1) are 101 Examples of the chain alkyl group and the chain alkenyl group in the above formula (1) include groups in which one hydrogen atom has been removed from the groups exemplified as the chain alkyl group and the chain alkenyl group in the above formula (1).

[0287] In the above formula (ca-4), x is 1 or 2. W 201 is a (x+1)-valent linking group, that is, a divalent or trivalent linking group. W 201 The divalent linking group in the above formula (a2-1) is preferably a divalent hydrocarbon group which may have a substituent. 21 Examples of the divalent hydrocarbon groups which may have a substituent include those shown in the above. 201 The divalent linking group in may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and the phenylene group is particularly preferred. W 201 The trivalent linking group in 201 and a group in which one hydrogen atom has been removed from the divalent linking group represented by the formula: W 201 As the trivalent linking group in the formula (I), a group in which two carbonyl groups are bonded to an arylene group is preferable.

[0288] Specific examples of suitable cations represented by the above formula (ca-1) include cations represented by the following chemical formulas (ca-1-1) to (ca-1-70).

[0289] [ka]

[0290] [ka]

[0291] [ka] [In the formula, g1, g2, and g3 each represent a repeating number, 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.]

[0292] [ka]

[0293] [ka]

[0294] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent, and the substituent is the above-mentioned R 201 ~R 207 , and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the

[0295] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, and the like.

[0296] 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).

[0297] [ka]

[0298] Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

[0299] [ka]

[0300] Among the above, the cationic portion ((M' m+ ) 1 / m ) is preferably a cation represented by general formula (ca-1).

[0301] In the resist composition of this embodiment, the component (B) may use either a single type, or a combination of two or more types. When the resist composition contains the component (B), the amount of the component (B) in the resist composition is preferably less than 50 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 5 to 35 parts by mass, per 100 parts by mass of the component (A). By setting the content of the component (B) within the above-mentioned preferred range, sufficient pattern formation can be achieved. Furthermore, when each component of the resist composition is dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is also favorable.

[0302] <Base component (D)> The resist composition of this embodiment may further contain, in addition to the component (A), 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 to light and loses its acid diffusion controllability, 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 suppression of the occurrence of coating defects.

[0303] Regarding component (D1) By using a resist composition that contains 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 to light 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) do not act as quenchers in the exposed areas of the resist film because they decompose and lose their acid diffusion control ability (basicity), but they act as quenchers in the unexposed areas of the resist film.

[0304] [ka] [In the formula, Rd 1 ~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. 2In the formula, 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 organic cation having a valence of m.

[0305] {(d1-1) component} Anion part In formula (d1-1), Rd 1 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, each of which is represented by the R' 201 The same can be mentioned. Among these, Rd 1 As the substituent, 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 is preferable. The substituent which these groups may have includes a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5). 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). The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms. Specific examples of the chain alkyl group include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched alkyl groups such as 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.

[0306] When the chain 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 further 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. Rd 1 As the alkyl group, a fluorinated alkyl group in which some or all of the hydrogen atoms constituting a linear alkyl group are substituted with fluorine atoms is preferable, and a fluorinated alkyl group in which all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms (linear perfluoroalkyl group) is particularly preferable.

[0307] Preferred specific examples of the anion moiety of the component (d1-1) are shown below.

[0308] [ka]

[0309] ··Cation part In formula (d1-1), M m+ is an m-valent organic cation. M m+Suitable organic cations include those similar to those represented by the general formulas (ca-1) to (ca-4), more preferably those represented by the general formula (ca-1), and even more preferably those represented by the general formulas (ca-1-1) to (ca-1-70). The component (d1-1) may be used alone or in combination of two or more.

[0310] {Component (d1-2)} Anion part In formula (d1-2), Rd 2 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 the R' 201 The same can be mentioned. However, Rd 2 In the above, the carbon atom adjacent to the S atom does not have a fluorine atom bonded thereto (is not substituted with fluorine), and this makes the anion of the (d1-2) component an appropriate weak acid anion, thereby improving the quenching ability of the (D) component. Rd 2 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. The aliphatic cyclic group is more preferably a group (which may have a substituent) in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor, or the like. Rd 2 The hydrocarbon group may have a substituent, and examples of the substituent include Rd 1 Examples of the substituent include the same as the substituents that may be possessed by the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above.

[0311] Preferred specific examples of the anion moiety of the component (d1-2) are shown below.

[0312] [ka]

[0313] ··Cation part In formula (d1-2), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-2) may be used alone or in combination of two or more.

[0314] {Component (d1-3)} Anion part 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, 201 The Rd is preferably a fluorine atom-containing cyclic group, a chain alkyl group, or a chain alkenyl group. Among these, a fluorinated alkyl group is preferred, and the Rd 1 More preferred are the same fluorinated alkyl groups as those mentioned above.

[0315] 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 the R' 201 The same can be mentioned. Among these, an alkyl group, an alkoxy group, an alkenyl group, or a cyclic group, each of which may have a substituent, is preferable. Rd 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, or the like. Rd 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 preferable.

[0316] Rd 4 The alkenyl group in R' 201 Examples of the alkenyl group include the same as the alkenyl group in the above, and a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group, and a 2-methylpropenyl group 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.

[0317] Rd 4 The cyclic group in R' 201 Examples of the cyclic groups include those similar to those in the above formula, and preferred are alicyclic groups obtained by removing one or more hydrogen atoms from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane, or aromatic groups such as a phenyl group or a naphthyl group. 4 When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, and the lithography properties become good. 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.

[0318] In formula (d1-3), Yd 1 is a single bond or a divalent linking group. Yd 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. 21Examples 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 mentioned in the description of the divalent linking group in the above. Yd 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.

[0319] Preferred specific examples of the anion moiety of the component (d1-3) are shown below.

[0320] [ka]

[0321] [ka]

[0322] ··Cation part In formula (d1-3), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-3) may be used alone or in combination of two or more.

[0323] 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 20 parts by mass, and even more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the component (A). When the amount of the component (D1) is at least as large as the preferred lower limit, particularly good lithography properties and resist pattern shape are likely to be obtained, while when it is no more than the upper limit, good sensitivity can be maintained and excellent throughput is also achieved.

[0324] Manufacturing method of component (D1): The method for producing the components (d1-1) and (d1-2) is not particularly limited, and they can be produced by known methods. The method for producing the component (d1-3) is not particularly limited, and it can be produced, for example, in a manner similar to that described in US2012-0149916.

[0325] Regarding component (D2) The component (D) 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 component (D1). The component (D2) is not particularly limited as long as it acts as an acid diffusion control agent and does not fall under the category of component (D1), 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. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms. Examples of aliphatic amines include amines in which at least one hydrogen atom of ammonia NH3 has been 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 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

[0326] 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 the aliphatic monocyclic amine include piperidine and piperazine. The aliphatic polycyclic amine preferably has 6 to 10 carbon atoms, and specific examples thereof include 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.

[0327] 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.

[0328] Furthermore, an aromatic amine may be used as the component (D2). Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, and N-tert-butoxycarbonylpyrrolidine.

[0329] The component (D2) may be used alone or in combination of two or more types. When the resist composition contains the component (D2), the amount of the component (D2) in the resist composition is usually within the range of 0.01 to 5 parts by mass relative to 100 parts by mass of the component (A). By ensuring that the amount is within this range, the resist pattern shape, the storage stability over time, and the like are improved.

[0330] <At least one compound (E) selected from the group consisting of organic carboxylic acids, phosphorus oxoacids and derivatives thereof> The resist composition of this embodiment may contain, as an optional component, at least one compound (E) selected from the group consisting of organic carboxylic acids, and phosphorus oxoacids and derivatives thereof (hereafter referred to as "component (E)") for the purposes of preventing deterioration of sensitivity and improving the resist pattern shape and stability over time after exposure. Suitable organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Examples of derivatives of phosphorus oxoacids include esters in which the hydrogen atoms of the above oxoacids are substituted with hydrocarbon groups. Examples of the hydrocarbon groups include alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Examples of the derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphoric acid ester and diphenyl phosphoric acid ester. Examples of the derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid. In the resist composition of this embodiment, the component (E) may use either a single type, or a combination of two or more types. When the resist composition contains the component (E), the amount of the component (E) is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A).

[0331] <Fluorine additive component (F)> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as “component (F)”) in order to impart water repellency to the resist film or to improve lithography properties. As the component (F), for example, fluorine-containing polymeric compounds described in JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, and JP-A-2011-128226 can be used. More specifically, the component (F) may be a polymer having a structural unit (f1) represented by the following general formula (f1-1). The polymer is preferably a polymer (homopolymer) consisting of only the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) and the structural unit (a1); or a copolymer of the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and 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.

[0332] [ka] [In the formula, R is the same as above, and Rf 102 and Rf 103 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; Rf 102 and Rf 103 may be the same or different. 1 is an integer from 0 to 5, and Rf 101 is an organic group containing a fluorine atom.

[0333] 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. In formula (f1-1), Rf 102 and Rf 103 Examples of the halogen atom in Rf include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. 102 and Rf 103 Examples of the alkyl group having 1 to 5 carbon atoms in R 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 103Specific 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. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. 102 and Rf 103 is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group. In formula (f1-1), nf 1 represents an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0334] 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 fluorine atom-containing hydrocarbon group may be linear, branched or cyclic and preferably has 1 to 20 carbon atoms, more preferably has 1 to 15 carbon atoms, and particularly preferably has 1 to 10 carbon atoms. Furthermore, in the hydrocarbon group containing fluorine atoms, preferably 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more are fluorinated, as this enhances the hydrophobicity of the resist film during immersion exposure. Among them, Rf 101 is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a trifluoromethyl group, -CH2-CF3, -CH2-CF2-CF3, -CH(CF3)2, -CH2-CH2-CF3, or -CH2-CH2-CF2-CF2-CF2-CF3.

[0335] The weight average molecular weight (Mw) of component (F) (based on polystyrene conversion by gel permeation chromatography) is preferably 1000 to 50000, more preferably 5000 to 40000, and most preferably 10000 to 30000. When it is below the upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is above the lower limit of this range, the resist film has good water repellency. The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.0 to 2.5.

[0336] In the resist composition of this embodiment, the component (F) may use either a single type, or a combination of two or more types. When the resist composition contains the component (F), the component (F) is typically used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

[0337] <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 those known in the art as a solvent for chemically amplified resist compositions. Examples of the (S) component include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; and compounds having an ether bond such as monoalkyl ethers, monoethyl ethers, monopropyl ethers, and monobutyl ethers of the above-mentioned polyhydric alcohols or compounds having an ester bond, or monophenyl ethers. derivatives of polyhydric alcohols (among these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred); cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene, and dimethyl sulfoxide (DMSO). In the resist composition of this embodiment, the component (S) may be used alone or as a mixed solvent of two or more kinds. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0338] As the component (S), a mixed solvent of PGMEA and a polar solvent is also preferred. The blending ratio (mass ratio) may be appropriately determined taking into consideration the compatibility between PGMEA and the polar solvent, and is preferably within the range of 1:9 to 9:1, and more preferably 2:8 to 8:2. More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA:EL or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3. Furthermore, a mixed solvent of PGMEA, PGME, and cyclohexanone is also preferred. As the component (S), a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone is also preferred. In this case, the mixing ratio of the former to the latter is preferably 70:30 to 95:5 by mass. The amount of the component (S) used is not particularly limited, and is set appropriately depending on the coating film thickness at a concentration that allows application to a substrate, etc. In general, the component (S) is used so that the solids concentration of the resist composition falls within the range of 0.1 to 20 mass %, and preferably 0.2 to 15 mass %.

[0339] The resist composition of the present 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.

[0340] In the resist composition of this embodiment, after dissolving the resist material in the component (S), impurities and the like 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.

[0341] In the resist composition of this embodiment, the component (A) contains a resin component (A1) that contains the structural unit (a0), and the proportion of the structural unit (a0) in (A1) is 58 to 80 mol % relative to the total (100 mol %) of all structural units constituting the component (A1). In the structural unit (a0), Ra 01 and an aromatic hydrocarbon group which may have a substituent of Ra 02 and Ra 03 and a hydrocarbon group which may have a substituent of Ra 01 ~Ra 03 and the carbon atom to which the acid dissociable group [-C(Ra 01 )(Ra 02 )(Ra 03 ) is formed. 01 is a tertiary carbon atom bonded to a carbonyloxy group (C(=O)-O-), 0 A carbon atom C1 adjacent to the carbon atom C1 and a carbon atom Ya adjacent to the carbon atom C1 0 It forms an unsaturated double bond with the carbon atom C2 other than the acid dissociable group [-C(Ra 01 )(Ra 02 )(Ra 03 The carbocation generated when the structural unit (a0) is dissociated is more stable than the carbocation generated when an acid dissociable group that does not form an unsaturated double bond with the carbon C1 and the carbon C2 is dissociated. Therefore, the acid dissociability of the structural unit (a0) is improved. Furthermore, since the structural unit (a0) has a bulky structure, the diffusion of the acid can be well controlled. In conventional resist compositions, the content of the structural unit containing an acid-dissociable group in the base component was often set to 50 mol % or less relative to the total (100 mol %) of all structural units constituting the component (A1), taking into consideration the balance with other structural units. However, the present inventors have found that by increasing the content of the structural unit (a0) having the above-mentioned specific structure to 58 to 80 mol %, lithography properties such as improved roughness can be further improved.

[0342] (Method of forming resist pattern) A method for forming a resist pattern according to a second aspect of the present invention is a method comprising the steps of forming a resist film on a support using the resist composition of the above-described embodiment, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. One embodiment of the resist pattern forming method is, for example, a resist pattern forming method carried out as follows.

[0343] First, the resist composition of the above-described embodiment is applied onto a support using a spinner or the like, and then baked (post-applied bake (PAB)) at a temperature of, for example, 80 to 150° C. for 40 to 120 seconds, preferably 60 to 90 seconds, 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 lithography using direct irradiation with an electron beam without using a mask pattern, and then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed using an alkaline developer in the case of an alkaline development process, or a developer containing an organic solvent (organic developer) in the case of a solvent development process.

[0344] After the development process, a rinse process is preferably carried out. In the case of an alkaline development process, the rinse process is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse liquid containing an organic solvent is preferably used. In the case of a solvent development process, after the development treatment or rinsing treatment, a treatment may be carried out in which the developer or rinsing liquid adhering to the pattern is removed by using a supercritical fluid. After the development treatment or rinsing treatment, drying is performed. In some cases, a baking treatment (post-baking) may be performed after the development treatment. In this manner, a resist pattern can be formed.

[0345] The support is not particularly limited, and may be a conventionally known support, such as a substrate for electronic components or a substrate on which a predetermined wiring pattern is formed. More specifically, it may be a silicon wafer, a substrate made of metal such as copper, chromium, iron, or aluminum, or a glass substrate. As the material for the wiring pattern, for example, copper, aluminum, nickel, or gold may be used. The support may be a substrate as described above on which an inorganic and / or organic film is provided. Examples of inorganic films include inorganic anti-reflective coatings (inorganic BARC). Examples of organic films include organic anti-reflective coatings (organic BARC) and organic films such as lower organic films in a multi-layer resist method. Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the lower organic film is patterned using the resist pattern formed on the upper resist film as a mask, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be made thin, and a fine pattern with a high aspect ratio can be formed. Multilayer resist methods are basically divided into a two-layer structure consisting of an upper resist film and a lower organic film (two-layer resist method), and a three-layer structure consisting of three or more layers with one or more intermediate layers (such as a thin metal film) provided between the upper resist film and the lower organic film (three-layer resist method).

[0346] The wavelength used for exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, and soft X-ray can be used. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB, or EUV, more useful for ArF excimer laser, EB, or EUV, and particularly useful for EB or EUV. That is, the resist pattern forming method of this embodiment is a particularly useful method when the step of exposing the resist film includes an operation of exposing the resist film to EUV (extreme ultraviolet) or EB (electron beam).

[0347] The exposure method for the resist film may be a normal exposure method (dry exposure) performed in air or an inert gas such as nitrogen, or may be liquid immersion lithography. Immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure tool is filled with a solvent (immersion medium) that has a refractive index greater than that of air, and then exposure (immersion exposure) is performed in that state. The immersion medium is preferably a solvent having a refractive index larger than that of air and smaller than that of the resist film to be exposed. The refractive index of the solvent is not particularly limited as long as it is within the above range. Examples of the solvent having a refractive index larger than that of air and smaller than that of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent. Specific examples of the fluorine-based inert liquid include liquids mainly composed of fluorine-based compounds such as C3HCl2F5, C4F9OCH3, C4F9OC2H5, and C5H3F7, and preferably have a boiling point of 70 to 180° C., more preferably 80 to 160° C. If the fluorine-based inert liquid has a boiling point in the above range, it is preferable because the medium used for immersion can be removed in a simple manner after exposure is completed. As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are replaced with fluorine atoms is particularly preferred. Specific examples of the perfluoroalkyl compound include perfluoroalkyl ether compounds and perfluoroalkylamine compounds. More specifically, the perfluoroalkyl ether compound may be perfluoro(2-butyl-tetrahydrofuran) (boiling point 102°C), and the perfluoroalkylamine compound may be perfluorotributylamine (boiling point 174°C). As the liquid immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility, and the like.

[0348] An example of an alkaline developer used in the development treatment in the alkaline development process is a 0.1 to 10 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 capable of dissolving the component (A) (the component (A) before exposure), and may be appropriately selected from known organic solvents. Specific examples of the organic solvent include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, and hydrocarbon solvents. Ketone-based solvents are organic solvents that contain CC(=O)-C in their structure. Ester-based solvents are organic solvents that contain CC(=O)-OC in their structure. Alcohol-based solvents are organic solvents that contain an alcoholic hydroxyl group in their structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile-based solvents are organic solvents that contain a nitrile group in their structure. Amide-based solvents are organic solvents that contain an amide group in their structure. Ether-based solvents are organic solvents that contain COC in their structure. Some organic solvents contain multiple types of functional groups that characterize the above-mentioned solvents in their structures, and in such cases, the organic solvent is considered to fall under any of the solvent types that contain the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether is considered to fall under both the alcohol-based solvents and the ether-based solvents in the above classification. The hydrocarbon solvent is a hydrocarbon solvent that is composed of a hydrocarbon that may be halogenated and has no substituents other than halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Of the above, the organic solvent contained in the organic developer is preferably a polar solvent, and more preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

[0349] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), etc. Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

[0350] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, methoxyethyl acetate, ethoxyethyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, 2-ethoxybutyl ... dibutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, proline lactate Examples of the ester-based solvent include pyru, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, etc. Among these, butyl acetate is preferred as the ester-based solvent.

[0351] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0352] The organic developer may contain known additives as necessary. Examples of such additives include surfactants. The surfactant is not particularly limited, but may be, for example, an ionic or nonionic fluorine-based and / or silicon-based surfactant. The surfactant is preferably a nonionic surfactant, more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant. When a surfactant is added, the amount added is usually from 0.001 to 5 mass %, preferably from 0.005 to 2 mass %, and more preferably from 0.01 to 0.5 mass %, based on the total amount of the organic developer.

[0353] 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 there for a certain period of time (paddle method), a method of spraying the developer on the surface of the support (spray method), and 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).

[0354] The organic solvent contained in the rinse solution used in the rinse treatment after the development treatment in the solvent development process can be selected appropriately from the organic solvents listed as the organic solvents used in the organic developer, and can be used if it is difficult to dissolve the resist pattern.Usually, at least one solvent selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, and an ether solvent is used.Among these, at least one solvent selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, and an amide solvent is preferred, at least one solvent selected from an alcohol solvent and an ester solvent is more preferred, and an alcohol solvent is particularly preferred. The alcohol-based solvent used in the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be any of linear, branched, and cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred. These organic solvents may be used alone or in combination of two or more. They may also be used in combination with other organic solvents or water. However, in consideration of development characteristics, the amount of water in the rinse solution is preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the rinse solution. The rinse solution may contain known additives as necessary. Examples of such additives include surfactants. The surfactants include those similar to those described above, and nonionic surfactants are preferred, and nonionic fluorine-based surfactants or nonionic silicon-based surfactants are more preferred. When a surfactant is added, the amount of the surfactant added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse liquid.

[0355] The rinse treatment (cleaning treatment) using a rinse liquid can be carried out by a known rinse method, such as a method of continuously applying the rinse liquid onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse liquid for a certain period of time (dip method), or a method of spraying the rinse liquid onto the surface of the support (spray method).

[0356] According to the method of forming a resist pattern of the present embodiment described above, the resist composition related to the first aspect described above is used, so when forming a resist pattern, the lithography properties (reduction in roughness, etc.) are further improved and the resolution is increased, making it possible to form a resist pattern with a good shape. EXAMPLES

[0357] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In this example, the compound represented by chemical formula (1) is referred to as "compound (1)", and compounds represented by other chemical formulas are similarly referred to.

[0358] <Production examples of copolymer (A1-1) to copolymer (A1-14), copolymer (A2-1) to copolymer (A2-9)> Copolymers (A1-1) to (A1-14) and copolymers (A2-1) to (A2-9) were each obtained by known radical polymerization using monomers that derive the structural units constituting each copolymer in a given molar ratio.

[0359] The resulting copolymers (A1-1) to (A1-14) and (A2-1) to (A2-9) are shown below.

[0360] [ka]

[0361] [ka]

[0362] [ka]

[0363] For each of the obtained copolymers, 13The copolymer composition ratio of the copolymer (the ratio (molar ratio) of the constitutional units derived from each monomer) determined by C-NMR, and the weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) calculated in terms of standard polystyrene determined by GPC measurement are also shown in Tables 1 and 2.

[0364] [Table 1]

[0365] [Table 2]

[0366] <Preparation of Resist Composition> The components shown in Tables 3 and 4 were mixed and dissolved to prepare resist compositions of each example.

[0367] [Table 3]

[0368] [Table 4]

[0369] In Tables 3 and 4, the abbreviations have the following meanings. The numbers in brackets [ ] are the blend amounts (parts by mass). (A1)-1 to (A1)-14: The copolymers (A1-1) to (A1-14) (A2)-1~(A2)-9: The above copolymer (A2-1)~(A2-9) (B)-1: An acid generator represented by the following chemical formula (B-1). (D)-1: An acid diffusion inhibitor represented by the following chemical formula (D)-1. (S)-1: a mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 20 / 80 (mass ratio).

[0370] [ka]

[0371] <Evaluation of resist composition> A resist pattern was formed using the resulting resist composition, and the LWR was evaluated as follows.

[0372] [Resist pattern formation] Each resist composition of the examples was applied to a silicon substrate treated with hexamethyldisilazane (HMDS) using a spinner, and pre-baked (PAB) treatment was performed 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 35 nm. Next, the resist film was subjected to drawing (exposure) at an acceleration voltage of 100 kV using an electron beam lithography apparatus JEOL-JBX-9300FS (manufactured by JEOL Ltd.) with a target size of a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a line width of 32 nm, and then subjected to post-exposure baking (PEB) treatment at 90° C. for 60 seconds. Next, alkaline development was performed for 60 seconds using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23° C., and then water rinsing was performed with pure water for 15 seconds. As a result, a 1:1 LS pattern with a line width of 32 nm was formed.

[0373] [LWR evaluation] For the LS pattern formed in the above [Formation of resist pattern], 3σ, a scale indicating LWR, was obtained. "3σ" is a triple value (3σ) (unit: nm) of the standard deviation (σ) obtained from the measurement results obtained by measuring 400 line positions in the longitudinal direction of the line using a scanning electron microscope (accelerating voltage 800V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation), and is shown in Tables 3 and 4. The smaller the 3σ value, the smaller the roughness of the line sidewall, meaning that a LS pattern with a more uniform width was obtained.

[0374] From the results shown in Table 3, it was confirmed that the resist compositions of Examples 1 to 7 had improved LWR compared to the resist compositions of Comparative Examples 1 to 4. The results shown in Table 4 confirm that, compared to the resist compositions of Comparative Examples 5-9, the resist compositions of Examples 8-14 had improved LWR.

Claims

1. A resist composition which generates an acid upon exposure and changes its solubility in a developer by the action of the acid, The composition contains a base component (A) whose solubility in a developer changes under the action of an acid, and an acid generator component (B) that generates an acid upon exposure to light, The base component (A) contains a resin component (A1) having a structural unit (a0) represented by the following general formula (a0-1-1) and a structural unit (a10) represented by the following general formula (a10-1): A resist composition, wherein the proportion of the structural unit (a0) in the resin component (A1) is 58 to 70 mol % relative to the total (100 mol %) of all structural units constituting the resin component (A1). 【Chemistry 1】 [In the formula, R ０１ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ０１ is a divalent hydrocarbon group which may have an ether bond. ａ０１ is an integer from 0 to 2. ０１ represents an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms as a substituent. Ya 01 represents a carbon atom. Xa 01 represents a group which, together with Ya 01 , forms a group obtained by removing one hydrogen atom from cyclopentane.] 【Chemistry 2】 [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. Ya x1 is a single bond or a divalent linking group. Wa x1 is an aromatic hydrocarbon group which may have a substituent. n ax1 is an integer of 1 or more.]

2. 13. 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; and developing the exposed resist film to form a resist pattern.

3. 3. The method for forming a resist pattern according to claim 2, wherein in the step of exposing the resist film, the resist film is exposed to EUV (extreme ultraviolet) or EB (electron beam).

Images