Resist composition, method for forming resist pattern, compound, radical polymerization initiator, and polymer

Abstract

The present invention employs a resist composition in which a resin component, whose solubility in a developing solution is changed by the action of an acid, includes a polymer having the group represented by general formula (I-1) at a terminal of the main chain thereof. In formula (I-1), R1 is a hydrocarbon group having 1-10 carbon atoms, Z is a hydrocarbon group or cyano group having 1-10 carbon atoms, and R1 and Z may be bonded to each other to form a ring. X is a divalent linking group. R2 is an ionic group comprising an anion group having an iodine atom and a counter cation thereof, an ionic group comprising a cation group having an iodine atom and a counter anion thereof, or a hydrocarbon group having at least an iodine atom as a substituent. The anion group having an iodine atom or the cation group having an iodine atom is bonded to X. Said resist composition makes it possible to achieve high sensitivity, increase a roughness reduction effect and an exposure latitude, and improve storage stability.

Description

Resist composition, resist pattern forming method, compound, radical polymerization initiator, polymer

[0001] This application claims priority to Japanese Patent Application No. 2024-012235, filed on January 30, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, advances in lithography technology have led to rapid advances in the miniaturization of patterns in the manufacturing of semiconductor devices and liquid crystal display devices. A common method for achieving this miniaturization is to shorten the wavelength (increase the energy) of the exposure light source.

[0003] Resist materials are required to have lithographic properties such as sensitivity to these exposure light sources and resolution capable of reproducing fine-sized patterns. To satisfy these requirements, chemically amplified resist compositions containing a base component whose solubility in a developer changes under the action of acid and an acid generator component that generates acid upon exposure have been used. In chemically amplified resist compositions, a polymeric compound having multiple structural units is generally used as the base component to improve lithographic properties, etc.

[0004] The polymeric compounds used in the base material components are typically produced by radical polymerization of monomers having various functions. Azo-based polymerization initiators such as azobisisobutyronitrile (AIBN) are commonly used as polymerization initiators in radical polymerization, and the partial structure of the azo-based polymerization initiator is introduced into the terminal of the produced polymeric compound. A polymeric compound having an acid-dissociable group introduced into the main chain terminal as the partial structure, and a resist composition containing the polymeric compound have been disclosed (see, for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2014-153686

[0006] As resist patterns become increasingly finer, for example, in lithography using EUV (extreme ultraviolet) or EB (electron beam), the goal is to form fine patterns of several tens of nanometers. As resist patterns become finer, it has become necessary to improve lithography properties such as roughness and exposure latitude while maintaining good sensitivity. However, these lithography properties are in a trade-off relationship, and improving one property tends to degrade the other. In addition, resist compositions are also required to have storage stability that suppresses deterioration of properties over time during storage.

[0007] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a resist composition that enables high sensitivity in resist pattern formation, improves both the effect of reducing roughness and the exposure latitude, and also exhibits good storage stability; a method of forming a resist pattern that uses the resist composition; and a compound, radical polymerization initiator, and polymer that are suitable for the resist composition.

[0008] In order to solve the above problems, the present invention employs the following configuration: That is, a first aspect of the present invention is a resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component whose solubility in a developer changes due to the action of the acid, the resin component including a polymer having a group represented by general formula (I-1) below at at least one end of its main chain:

[0009] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.]

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

[0011] A third aspect of the present invention is a compound represented by the following general formula (I):

[0012] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. The plurality of R present in the formula １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different. N is a nitrogen atom.

[0013] A fourth aspect of the present invention is a radical polymerization initiator comprising the compound according to the third aspect.

[0014] A fifth aspect of the present invention is a polymer having a group represented by the following general formula (I-1) at at least one end of the main chain:

[0015] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.]

[0016] According to the present invention, it is possible to provide a resist composition that achieves high sensitivity in resist pattern formation, improves both the effect of reducing roughness and the exposure latitude, and also exhibits excellent storage stability, a method of forming a resist pattern that uses the resist composition, and a compound, radical polymerization initiator, and polymer that are suitable for the resist composition.

[0017] In this specification and claims, "aliphatic" is a relative concept to aromatic, and is defined as meaning a group, compound, etc. that does not have aromaticity. "Alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups, unless otherwise specified. The same applies to alkyl groups in alkoxy groups. "Alkylene group" includes linear, branched, and cyclic divalent saturated hydrocarbon groups, unless otherwise specified. "Halogen atom" includes fluorine, chlorine, bromine, and iodine atoms. "Structural unit" means a monomer unit that constitutes a polymer compound (resin, polymer, copolymer). When describing "may have a substituent," it refers to cases where a hydrogen atom (-H) is replaced with a monovalent group, and cases where a methylene group (-CH ２ The term "exposure" encompasses both cases where the radical (-) is substituted with a divalent group.

[0018] An "acid-decomposable group" is a group having acid decomposability in which at least a part of the bond in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases by the action of an acid include groups that decompose by the action of an acid to generate a polar group. Examples of polar groups include a carboxy group, a hydroxyl group, an amino group, and a sulfo group (-SO ３ More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, groups in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0019] The term "acid-dissociable group" refers to either (i) a group having acid dissociability in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a part of the bond is cleaved by the action of an acid, followed by a decarboxylation reaction, in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Thus, when the acid-dissociable group is dissociated by the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, thereby increasing the polarity. As a result, the polarity of the entire resin 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.

[0020] A "base component" is an organic compound having film-forming ability. Organic compounds used as base components are broadly divided into non-polymers and polymers. As non-polymers, compounds having a molecular weight of 500 or more and less than 4000 are typically 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 polymers, compounds having a molecular weight of 1000 or more are typically used. Hereinafter, the terms "resin," "high molecular weight compound," or "polymer" refer to a polymer having a molecular weight of 1000 or more. The molecular weight of a polymer is determined by the weight average molecular weight in terms of polystyrene by GPC (gel permeation chromatography).

[0021] The term "derived structural unit" refers to a structural unit formed by cleavage of a multiple bond between carbon atoms, for example, an ethylenic double bond. In the "acrylic acid ester", the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R αｘ ) is an atom or group other than a hydrogen atom. αｘ ) is substituted with a substituent containing an ester bond, or αｘThis also includes α-hydroxyacrylic esters in which the α-position carbon atom of an acrylic ester is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-position carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, acrylic esters in which the hydrogen atom bonded to the α-position carbon atom has been replaced with a substituent may be referred to as α-substituted acrylic esters.

[0022] The term "derivative" is used to refer to a compound in which the hydrogen atom at the α-position of the target compound has been substituted with another substituent such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include a compound in which the hydrogen atom of the hydroxyl group of a target compound in which the hydrogen atom at the α-position may be substituted with a substituent has been substituted with an organic group; a compound in which the hydrogen atom at the α-position of the target compound may be substituted with a substituent to which a substituent other than a hydroxyl group is bonded; and the like. Unless otherwise specified, the α-position refers to the first carbon atom adjacent to the functional group. Examples of substituents that can be used to replace the hydrogen atom at the α-position of hydroxystyrene include R αｘ The same can be mentioned.

[0023] In this specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms, and may exist as enantiomers or diastereoisomers. In such cases, a single chemical formula represents all of the isomers. These isomers may be used alone or as a mixture.

[0024] (Resist Composition) One embodiment of the resist composition generates an acid upon exposure, and its solubility in a developer changes due to the action of the acid. This resist composition contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of an acid. The component (A) contains a resin component (A1) (hereinafter also referred to as "component (A1)") whose solubility in a developer changes due to the action of an acid, and the component (A1) includes a polymer having a specific group (a group represented by general formula (I-1)) having an iodine atom at at least one end of its main chain.

[0025] In the resist composition of this embodiment, the component (A) may generate an acid upon exposure, or an additive component formulated separately from the component (A) may generate an acid upon exposure. Specifically, the resist composition of this embodiment may further contain (1) an acid generator component that generates an acid upon exposure; (2) the component (A) may be a component that generates an acid upon exposure; or (3) the component (A) may be a component that generates an acid upon exposure and further contain an acid generator component. That is, in the cases of (2) and (3) above, the component (A) is a "base component that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid." When the component (A) is a base component that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, it is preferable that the polymer generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid. As such a polymer, a copolymer having a structural unit that generates an acid upon exposure can be used. The structural unit that generates acid upon exposure to light can be the structural unit (a5) or the structural unit (a6) described below.

[0026]

[0043] When a resist film is formed using the resist composition of this embodiment and the resist film is subjected to selective exposure, an acid is generated from the acid generator component in the exposed areas of the resist film, for example, and the solubility of the component (A) in a developer changes due to the action of the acid, whereas the solubility of the component (A) in a developer does not change in the unexposed areas of the resist film, resulting in a difference in solubility in a developer between the exposed and unexposed areas of the resist film. Therefore, when the resist film is developed, if the resist composition is positive, the exposed areas of the resist film are dissolved and removed, forming a positive resist pattern, whereas if the resist composition is negative, the unexposed areas of the resist film are dissolved and removed, forming a negative resist pattern.

[0027] The resist composition of this embodiment may be a positive resist composition or a negative resist composition. Furthermore, the resist composition of this embodiment may be for use in an alkaline development process in which an alkaline developer is used in the development treatment during resist pattern formation, or for use in a solvent development process in which a developer containing an organic solvent (organic developer) is used in the development treatment.

[0028] <Base Component (A)> In the resist composition of this embodiment, the component (A) contains at least the resin component (A1). That is, the component (A) contains at least a resin component containing a polymer whose solubility in a developer changes under the action of an acid and which has a group represented by general formula (I-1) at at least one end of its main chain. By using such a component (A1), the polarity of the base component changes before and after exposure, thereby achieving good development contrast not only in alkaline development processes but also in solvent development processes. In addition, high sensitivity is achieved in resist pattern formation, and both the effect of reducing roughness and the exposure latitude are enhanced. Furthermore, storage stability is also improved. As the component (A), at least one other polymeric compound and low molecular weight compound may be used in combination with the component (A1). The proportion of the component (A1) in the component (A) is preferably 25% by mass or more, more preferably 50% by mass or more, even more preferably 75% by mass or more, relative to the total mass of the component (A), and may even be 100% by mass. If the proportion is 25% by mass or more, the above-mentioned effects, good lithography properties, and a good resist pattern shape are more likely to be obtained.

[0029] Regarding the Component (A1) The component (A1) is a resin component whose solubility in a developer changes under the action of an acid. In addition, the component (A1) includes a polymer having a group represented by general formula (I-1) described below at at least one end of its main chain (hereinafter, this may be referred to as the "component (A1-0)"). In the resist composition of this embodiment, the component (A1) may consist solely of the component (A1-0), or may be a combination of the component (A1-0) and a polymer whose solubility in a developer changes under the action of an acid (excluding polymers corresponding to the component (A1-0)); hereinafter, this may be referred to as the "component (A2)").

[0030] Regarding the Component (A1-0): The component (A1-0) is a polymer having a group represented by the following general formula (I-1) at at least one end of its main chain. This component (A1-0) preferably has a structural unit (a1) containing an acid-decomposable group whose polarity increases under the action of acid. A preferred component (A1-0) may have other structural units in addition to the structural unit (a1), as necessary.

[0031] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.]

[0032] In the formula (I-1), R １ In the formula (I), the hydrocarbon group having 1 to 10 carbon atoms may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Among these, an aliphatic hydrocarbon group is preferred, and a monovalent aliphatic saturated hydrocarbon group (alkyl group) is more preferred. More specific examples of the alkyl group include chain-like aliphatic hydrocarbon groups (straight-chain or branched-chain alkyl groups) and aliphatic hydrocarbon groups containing a ring in their structure. The straight-chain alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms, and most preferably 1 to 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and the like. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, with a methyl group or an ethyl group being particularly preferred. The branched-chain alkyl group 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, and the like, with an isopropyl group or a tert-butyl group being most preferred. Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of the aforementioned chain-like aliphatic hydrocarbon group, or groups in which the cyclic aliphatic hydrocarbon group is interposed in the chain-like aliphatic hydrocarbon group. The cyclic aliphatic hydrocarbon group preferably has 3 to 8 carbon atoms, more preferably 4 to 6 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane. The cyclic aliphatic hydrocarbon group may have a substituent. Examples of such substituents include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (═O).

[0033] In the formula (I-1), Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group (—CN). The hydrocarbon group having 1 to 10 carbon atoms in Z includes the above-mentioned R １ Examples of the hydrocarbon groups include those having 1 to 10 carbon atoms.

[0034] In the formula (I-1), R １and Z may be bonded to each other to form a ring. １ and Z are each independently a linear or branched alkyl group, and R １ The terminals of R and Z may be bonded to each other to form a ring. １ and Z and R １ The ring formed by Z and the carbon atom to which it is bonded is preferably a ring having 3 to 8 carbon atoms, more preferably cyclopentane, cyclohexane, cycloheptane or cyclooctane, and particularly preferably cyclohexane.

[0035] Among them, R １ and Z is a combination of a methyl group and a methyl group, a combination of an ethyl group and an ethyl group, a combination of a methyl group and a cyano group, a combination of an ethyl group and a cyano group; １ and Z and R １ and Z are preferably a group formed by removing two hydrogen atoms from cyclohexane, which is formed by the carbon atom to which both are bonded. １ A particularly preferred combination is where is a methyl group and Z is a cyano group.

[0036] In the formula (I-1), X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)-, and an alkylene group. Examples of the divalent linking group (excluding those containing a sulfide bond (-S-)) for X include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom.

[0037] Divalent hydrocarbon group which may have a substituent: "The hydrocarbon group has a substituent" means that some or all of the hydrogen atoms in the hydrocarbon group have been substituted with groups or atoms other than hydrogen atoms. The divalent hydrocarbon group which may have a substituent may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0038] More specific examples of the aliphatic hydrocarbon group in the divalent hydrocarbon group include chain aliphatic hydrocarbon groups (straight-chain or branched-chain aliphatic hydrocarbon groups) and aliphatic hydrocarbon groups containing a ring in the structure. The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, even more preferably 1 to 5, and most preferably 1 or 2. The straight-chain aliphatic hydrocarbon group is preferably a straight-chain alkylene group, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched chain aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, even more preferably 3 to 8 carbon atoms, and most preferably 3 to 5 carbon atoms. As the branched chain aliphatic hydrocarbon group, a branched chain alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, and other alkyl alkylene groups such as alkyl tetramethylene groups. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. The linear aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and an oxygen atom (═O).

[0039] Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of the aforementioned chain-like aliphatic hydrocarbon group, or groups in which the cyclic aliphatic hydrocarbon group is interposed in the middle of the chain-like aliphatic hydrocarbon group. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. Preferred monocyclic groups are groups in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms, and examples of such monocycloalkanes include cyclopentane and cyclohexane. Preferred polycyclic groups are groups in which two hydrogen atoms have been removed from a polycycloalkane having 7 to 12 carbon atoms, and specific examples of such polycycloalkanes include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. The cyclic aliphatic hydrocarbon group may or may not have a substituent, which may include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and an oxygen atom (═O).

[0040] The aromatic hydrocarbon group in the divalent hydrocarbon group is a divalent hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group of an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1. The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and an oxygen atom (═O).

[0041] Divalent linking group containing a heteroatom: Examples of the divalent linking group containing a heteroatom include -O-, -C(=O)-, -O-C(=O)-, -O-C(=O)-O-, -NH-, -NH-C(=O)-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S(=O) ２ -, -S(=O) ２ Examples of the divalent hydrocarbon group include -O-, -A-O(oxygen atom)-B- (wherein A and B are each independently a divalent hydrocarbon group which may have a substituent), or a combination of a divalent hydrocarbon group which may have a substituent and a divalent linking group which contains a hetero atom. Examples of the divalent hydrocarbon group which may have a substituent include the same as those described above (divalent hydrocarbon group which may have a substituent), and linear, branched, or aliphatic hydrocarbon groups which contain a ring in their structure are preferred.

[0042] In the case of the above -NH-, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

[0043] In the above-mentioned "A-O-B", A and B are each independently a divalent hydrocarbon group which may have a substituent. The hydrocarbon group for A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group and aromatic hydrocarbon group for A are the same as the aliphatic hydrocarbon group and aromatic hydrocarbon group in the above-mentioned description of the divalent hydrocarbon group which may have a substituent. Among them, A is preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated. More specific examples of the aliphatic hydrocarbon group for A include linear or branched aliphatic hydrocarbon groups and aliphatic hydrocarbon groups containing a ring in the structure. Among them, A is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, and even more preferably a linear alkylene group having 2 to 5 carbon atoms. Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those listed above for A. B is preferably an aliphatic hydrocarbon group, more preferably a linear or branched aliphatic hydrocarbon group, and particularly preferably a methylene 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.

[0044] When X is composed of only one of -O-, -O-C(=O)-, -NH-C(=O)-, or -NH-C(=NH)-, X is preferably -O-C(=O)- or -NH-C(=O)-. In this case, the carbon atom (C) in -O-C(=O)- or the carbon atom (C) in -NH-C(=O)- is preferably R １and is preferably directly bonded to the carbon atom to which Z is bonded. When X is a combination of any of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)- or -NH-C(=NH)- as described above, and a divalent group (a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom), X is preferably a combination of any of -O-, -O-C(=O)-, -NH-C(=O)- or -NH-C(=NH)- and a divalent hydrocarbon group which may have a substituent. a combination of any of -O-, -O-C(=O)-, -NH-C(=O)-, or -NH-C(=NH)- with a linear or branched aliphatic hydrocarbon group having 1 to 5 carbon atoms is preferred; a combination of any of -O-, -O-C(=O)-, -NH-C(=O)-, or -NH-C(=NH)- with a methylene group or an ethylene group is even more preferred. The direction of the bond of -O-C(=O)-, -NH-C(=O)-, or -NH-C(=NH)- does not matter.

[0045] In this embodiment, X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)-, and an alkylene group, and is composed of a combination of any of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, or -NH-C(=NH)- and a chain aliphatic hydrocarbon group (linear or branched aliphatic hydrocarbon group) having 1 to 10 carbon atoms. a combination of any of —O—, —O—C(═O)—, —NH—C(═O)— or —NH—C(═NH)— with a linear or branched alkylene group having 1 to 10 carbon atoms is more preferred; a combination of —O—C(═O)— and a methylene group or an ethylene group; a combination of —C(═O)—O—, a methylene group or an ethylene group, and —NH—C(═O)—; or a combination of —O—, a methylene group or an ethylene group, and —NH—C(═O)— is particularly preferred.

[0046] In the above description of X, the direction of the bond in the divalent linking group does not matter. For example, -O-C(=O)- may be -C(=O)-O-, and -NH-C(=O)- may be -C(=O)-NH-. The combination of -O-C(=O)- and a methylene group or an ethylene group may be either -O-C(=O)-(methylene group or ethylene group)- or -C(=O)-O-(methylene group or ethylene group)-. A combination of -C(=O)-O-, a methylene group or an ethylene group, and -NH-C(=O)- may be any of -C(=O)-O-(methylene group or ethylene group)-NH-C(=O)-, -C(=O)-O-(methylene group or ethylene group)-C(=O)-NH-, -O-C(=O)-(methylene group or ethylene group)-NH-C(=O)-, and -O-C(=O)-(methylene group or ethylene group)-C(=O)-NH-. A combination of -O-, a methylene group or an ethylene group, and -NH-C(=O)- may be any of -O-(methylene group or ethylene group)-NH-C(=O)-, and -O-(methylene group or ethylene group)-C(=O)-NH-.

[0047] In the formula (I-1), R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent.

[0048] Regarding the ionic group (i): R ２ The ionic group (i) in the formula (I-1) is composed of an anionic group having an iodine atom and a counter cation thereof. However, in the ionic group (i), the anionic group having an iodine atom is bonded to X in the formula (I-1). The ionic group (i) is preferably a moiety that decomposes upon exposure to generate an acid. Examples of the anionic group include a sulfonate group (—SO ３ － ), a carboxylate group (—COO － As the counter cation, an onium cation is preferably used, and a sulfonium cation or an iodonium cation is more preferred.

[0049] Preferred examples of the ionic group (i) include ionic groups represented by the following general formula (i-1).

[0050] [In the formula, R Ａｒ１ is an aromatic group having at least an iodine atom as a substituent. １０ represents a divalent linking group or a single bond. ａｎ － is a sulfonate group (-SO ３ － ) or a carboxylate group (—COO － ) M ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. * represents a bond to the X.

[0051] In the formula (i-1), R Ａｒ１ is an aromatic group having at least an iodine atom as a substituent. Ａｒ１ The aromatic group in may be monocyclic or polycyclic. The aromatic ring contained in the aromatic group preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 10 carbon atoms.

[0052] Specific examples of the aromatic ring contained in the aromatic group include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a portion of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of heteroatoms in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic group include a group in which two hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, more preferably a group in which two hydrogen atoms have been removed from benzene or naphthalene (i.e., a phenylene group or a naphthylene group), and even more preferably a group in which two hydrogen atoms have been removed from benzene (i.e., a phenylene group).

[0053] R Ａｒ１The aromatic group in has at least an iodine atom as a substituent. When the aromatic ring contained in the aromatic group is benzene, the number of iodine atoms bonded to the benzene may be 1 to 3, and from the viewpoint of sensitivity or exposure latitude, 2 or 3 is preferred, and 3 is more preferred. From the viewpoint of reducing roughness, 1 or 2 is preferred, and 2 is more preferred. Ａｒ１ The aromatic group in may have a substituent other than an iodine atom. Examples of the substituent other than an iodine atom include an alkyl group, a halogenated alkyl group, a halogen atom other than an iodine atom, a hydroxy group, and an alkoxy group.

[0054] In the formula (i-1), L １０ is a divalent linking group or a single bond. １０ Examples of the divalent linking group in L include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. １０ Examples of the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in X in formula (I-1) above include the same as those exemplified in the description of the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom. １０ is preferably, for example, one selected from the group consisting of an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—), an oxycarbonyl group (—O—C(═O)—), a linear or branched alkylene group, a linear or branched fluorinated alkylene group, and a single bond; and more preferably a combination of one selected from the group consisting of —O—, —C(═O)—O—, and —O—C(═O)— with one selected from the group consisting of a linear or branched alkylene group, and a linear or branched fluorinated alkylene group, or a single bond.

[0055] In the formula (i-1), Y ａｎ － is a sulfonate group (-SO ３ － ) or a carboxylate group (—COO － )

[0056] Y ａｎ－ is a sulfonate group (-SO ３ － ), the anion moiety in the ionic group (i) preferably has a structure represented by the following general formula:

[0057] General formula: *-R Ａｒ１ -Y １１０ -V １０ -C(R １０１ ) (R １０２ )-SO ３ － R Ａｒ１ is R in the above formula (i-1). Ａｒ１ It is the same as Y １１０ represents a divalent linking group or a single bond. １０ represents a fluorinated alkylene group, an alkylene group, or a single bond. １０１ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. １０２ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. * represents a bond to the aforementioned X.

[0058] In the general formula, Y １１０ Examples of the divalent linking group in X in formula (I-1) include the same as the divalent linking group containing a hetero atom in Y １１０ is preferably an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—) or an oxycarbonyl group (—O—C(═O)—), and (R Ａｒ１ side) -C(=O)-O-(V １０ It is more preferable that the side is the side.

[0059] In the general formula, V １０ Examples of the alkylene group in the formula (I-1) include the same chain aliphatic hydrocarbon group (straight-chain or branched-chain aliphatic hydrocarbon group) as X in the formula (I-1). １０ The fluorinated alkylene group in １０ In the above formula, some or all of the hydrogen atoms constituting the alkylene group are substituted with fluorine atoms. １０ is a methylene group (-CH ２ -), -CH(CF３ )- is preferred.

[0060] In the general formula, R １０１ R is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, preferably a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom, and more preferably a fluorine atom. １０２ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, preferably a fluorine atom or a hydrogen atom, and more preferably a fluorine atom.

[0061] Y ａｎ － is a carboxylate group (-COO － ), the anion moiety in the ionic group (i) preferably has a structure represented by the following general formula:

[0062] General formula: *-R Ａｒ１ -Y １２０ -C(=O)-O － R Ａｒ１ is R in the above formula (i-1). Ａｒ１ It is the same as Y １２０ represents a divalent linking group or a single bond. * represents a bond to the X.

[0063] In the general formula, Y １２０ Examples of the divalent linking group in X in formula (I-1) include the same as the divalent linking group containing a hetero atom in Y １２０ represents an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—), an oxycarbonyl group (—O—C(═O)—), a linear or branched alkylene group, any combination thereof, or a single bond, and is preferably a single bond.

[0064] In the formula (i-1), M ｍ＋ is an m-valent onium cation, and a sulfonium cation or an iodonium cation is preferred. m is an integer of 1 or more. Preferred cation moieties ((M ｍ＋ ) １／ｍ) includes onium cations represented by the following general formulas (ca-1) to (ca-3), respectively.

[0065] [In the formula, R ２０１ ~R ２０７ R each independently represents an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. ２０１ ~R ２０３ , R ２０６ ~R ２０７ may be bonded to each other to form a ring together with the sulfur atom in the formula. ２０８ ~R ２０９ R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２０１ represents —C(═O)— or —C(═O)—O—.]

[0066] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０７ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２０１ ~R ２０７ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２０１ ~R ２０７ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２０１ ~R ２０７ , and R ２１０ Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7):

[0067] [In the formula, R' ２０１are each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0068] Cyclic group which may have a substituent: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0069] R' ２０１ The aromatic hydrocarbon group in R' is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. ２０１ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R' include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. ２０１ Specific examples of the aromatic hydrocarbon group in the formula (I) include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0070] R' ２０１Examples of the cyclic aliphatic hydrocarbon group in the formula (I) include aliphatic hydrocarbon groups containing a ring within their structure. Examples of aliphatic hydrocarbon groups containing a ring within their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed within a linear or branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be either a polycyclic group or a monocyclic group. Preferred monocyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a monocycloalkane. Preferred monocycloalkanes have 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. Preferred polycyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkanes include adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ] Polycycloalkanes having a polycyclic skeleton of a bridged ring system, such as decane and tetracyclododecane; and polycycloalkanes having a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton, are more preferred.

[0071] Among them, R' ２０１ The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0072] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２-], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specifically, —CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0073] Also, R' ２０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, —SO 4 groups represented by the general formulae (b5-r-1) to (b5-r-4) described below, ２ -containing cyclic groups, and heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16).

[0074]

[0075] R' ２０１ Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. The halogen atom as a substituent is preferably a fluorine atom. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH ２ -) is a group that substitutes

[0076] A chain alkyl group which may have a substituent: R' ２０１The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0077] A chain alkenyl group which may have a substituent: R' ２０１ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of linear alkenyl groups include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of branched alkenyl groups include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the above chain alkenyl groups, linear alkenyl groups are preferred, with a vinyl group and a propenyl group being more preferred, and a vinyl group being particularly preferred.

[0078] R' ２０１ Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, the above-mentioned R' ２０１ Examples of the cyclic groups include the cyclic groups shown in the formula:

[0079] R' ２０１In addition to the above-mentioned optionally substituted cyclic groups, optionally substituted chain alkyl groups, and optionally substituted chain alkenyl groups, examples of the optionally substituted cyclic groups or optionally substituted chain alkyl groups include those similar to the acid-dissociable groups represented by formula (a1-r-2) described below.

[0080] Among them, R' ２０１ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane; a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7) described below; -SO represented by each of the general formulae (b5-r-1) to (b5-r-4) described below; ２ -containing cyclic groups are preferred.

[0081] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０３ , R ２０６ ~R ２０７ When they are bonded to each other to form a ring together with the sulfur atom in the formula, they are not substituted with heteroatoms such as sulfur atoms, oxygen atoms, and nitrogen atoms, or with carbonyl groups, -SO-, -SO ２ -, -SO ３ -, -COO-, -CONH- or -N(R Ｎ )-(the R Ｎ is an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0082] R ２０８ ~R ２０９each 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.

[0083] R ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２１０ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２１０ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２１０ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２１０ In the -SO ２ The -containing cyclic group is not particularly limited and any group can be used. Specific examples include groups represented by the following general formulae (b5-r-1) to (b5-r-4), and "-SO ２ -containing polycyclic group" is preferred, and a group represented by general formula (b5-r-1) is more preferred.

[0084] [In the formula, Rb' ５１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, or —SO ２ -containing cyclic group; B" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; n' is an integer of 0 to 2; * represents a bond.

[0085] In the general formulae (b5-r-1) and (b5-r-2), B" represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom. B" is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably a methylene group.

[0086] In the general formulae (b5-r-1) to (b5-r-4), Rb' ５１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group, and among these, are preferably each independently a hydrogen atom or a cyano group.

[0087] Specific examples of the groups represented by general formulae (b5-r-1) to (b5-r-4) are listed below, where "Ac" represents an acetyl group.

[0088]

[0089]

[0090]

[0091] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas.

[0092]

[0093]

[0094] [In the formula, g1, g2, and g3 represent the number of repeating units, where g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 1 to 20.]

[0095]

[0096]

[0097] [In the formula, R” ２０１ is a hydrogen atom or a substituent, and the substituent is the same as R ２０１ ~R２０７ and R ２１０ The substituents are the same as those exemplified as the substituents that may be possessed by

[0098]

[0099] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0100] 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).

[0101]

[0102] The cationic moiety ((M ｍ＋ ) １／ｍ ) is preferably a sulfonium cation, more preferably a cation represented by each of the formulas (ca-1) to (ca-3), still more preferably a cation represented by the formula (ca-1), and particularly preferably a cation represented by each of the formulas (ca-1-1) to (ca-1-84). In particular, from the viewpoint of increasing sensitivity, preferred cations represented by the formula (ca-1) are those having an electron-withdrawing group such as a fluorine atom, a fluorinated alkyl group, or a sulfonyl group as a substituent, and suitable examples thereof include cations selected from the group consisting of the cations represented by each of the chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84) above.

[0103] Specific examples of the group represented by formula (I-1) are listed below: ２ Specific examples where is the ionic group (i) are shown below: In the formula, [ ] indicates a terminal structure of the polymer main chain.

[0104]

[0105]

[0106] Regarding the ionic group (ii): R ２The ionic group (ii) in the formula (I-1) is composed of a cationic group having an iodine atom and its counter anion. However, in the ionic group (ii), the cationic group having an iodine atom is bonded to X in the formula (I-1). The ionic group (ii) is preferably a moiety that decomposes upon exposure to generate an acid. Suitable examples of the cationic group include onium cations, and more preferably sulfonium cations. Suitable examples of the counter anion include sulfonate anions and carboxylate anions.

[0107] Preferred examples of the ionic group (ii) include ionic groups represented by the following general formula (ii-1):

[0108] [In the formula, R Ａｒ２ R is an aromatic group which may have a substituent. ２１ and R ２２ are each independently an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent, or R ２１ and R ２２ are bonded to each other to form a ring together with the sulfur atom in the formula. Ａｒ２ , R ２１ and R ２２ At least one of Y has at least an iodine atom as a substituent. ＡＮ － is a sulfonate anion or a carboxylate anion. * represents a bond to the X.

[0109] In the formula (ii-1), R Ａｒ２ R is an aromatic group which may have a substituent. Ａｒ２ The aromatic group in may be monocyclic or polycyclic. The aromatic ring contained in the aromatic group preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 10 carbon atoms.

[0110] Specific examples of the aromatic ring contained in the aromatic group include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a portion of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of heteroatoms in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic group include a group in which two hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, more preferably a group in which two hydrogen atoms have been removed from benzene or naphthalene (i.e., a phenylene group or a naphthylene group), and even more preferably a group in which two hydrogen atoms have been removed from benzene (i.e., a phenylene group).

[0111] R Ａｒ２ The aromatic group in may have a substituent, for example, an alkyl group, a halogenated alkyl group, a halogen atom, a hydroxy group, an alkoxy group, or the like.

[0112] In the formula (ii-1), R ２１ and R ２２ are each independently an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent, or R ２１ and R ２２ are bonded to each other to form a ring together with the sulfur atom in the formula. ２１ and R ２２ As the group, R in the above general formula (ca-1) ２０１ ~R ２０３ Examples include the same as above. ２１ and R ２２ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２１ and R ２２ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２１ and R ２２ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２１ and R ２２Examples 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 above general formulae (ca-r-1) to (ca-r-7).

[0113] However, R Ａｒ２ , R ２１ and R ２２ At least one of R has at least an iodine atom as a substituent. Ａｒ２ , R ２１ and R ２２ are all benzene rings, the total number of iodine atoms bonded to the benzene rings is 1 to 3, and from the viewpoint of sensitivity or exposure latitude, it is preferably 2 or 3, and more preferably 3. From the viewpoint of reducing roughness, it is preferably 1 or 2, and more preferably 2.

[0114] In the formula (ii-1), Y ＡＮ － is a sulfonate or carboxylate anion.

[0115] Y ＡＮ － is a sulfonate anion, suitable examples of the anion moiety in the ionic group (ii) include anions represented by the following general formula (b-an-1) and anions represented by the following general formula (d1-an-2):

[0116] [In formula (b-an-1), R １０１ R is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group. １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０１ is a divalent linking group containing an oxygen atom or a single bond. １０１ is a single bond, an alkylene group, or a fluorinated alkylene group. １０１ and V １０１ In formula (d1-an-2), Rd ２is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the formula, no fluorine atom is bonded to the carbon atom adjacent to the S atom.]

[0117] Regarding the anion represented by the general formula (b-an-1), in the formula (b-an-1), R １０１ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0118] Cyclic group which may have a substituent: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. Furthermore, the aliphatic hydrocarbon group is preferably saturated.

[0119] R １０１ The aromatic hydrocarbon group in R is a hydrocarbon group having an aromatic ring. The number of carbon atoms in the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. １０１ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. １０１Specific examples of the aromatic hydrocarbon group in include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, benzyl group, phenethyl group, 1-naphthylmethyl group, etc.). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0120] R １０１ Examples of the cyclic aliphatic hydrocarbon group in the formula (I) include aliphatic hydrocarbon groups containing a ring within their structure. Examples of aliphatic hydrocarbon groups containing a ring within their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed within a linear or branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be either a polycyclic group or a monocyclic group. Preferred monocyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a monocycloalkane. Preferred monocycloalkanes have 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. Preferred polycyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkanes include adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ] Polycycloalkanes having a polycyclic skeleton of a bridged ring system, such as decane and tetracyclododecane; and polycycloalkanes having a polycyclic skeleton of a condensed ring system, such as a cyclic group having a steroid skeleton, are more preferred.

[0121] Among them, R １０１The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, further preferably an adamantyl group or a norbornyl group, and particularly preferably an adamantyl group.

[0122] The linear aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ -] and the like. The branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0123] Also, R １０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, —SO 2 represented by the general formulae (b5-r-1) to (b5-r-4) above, ２ -containing cyclic groups, and heterocyclic groups represented by the above chemical formulas (r-hr-1) to (r-hr-16), respectively.

[0124] R １０１Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. The halogen atom as a substituent is preferably a fluorine atom, a bromine atom, or an iodine atom. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH) constituting a cyclic hydrocarbon group. ２ -) is a group that substitutes

[0125] R １０１ The cyclic hydrocarbon group in may be a fused ring group containing a fused ring in which an aliphatic hydrocarbon ring and an aromatic ring are fused. Examples of the fused ring include a polycycloalkane having a bridged ring polycyclic skeleton to which one or more aromatic rings are fused. Specific examples of the bridged ring polycycloalkane include bicycloalkanes such as bicyclo[2.2.1]heptane (norbornane) and bicyclo[2.2.2]octane. The fused ring group is preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicycloalkane, and more preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicyclo[2.2.2]octane. １０１ Specific examples of the fused cyclic group in formula (b-an-1) include groups represented by the following formulae (r-br-1) and (r-br-2). １０１ represents a bond bonded to

[0126]

[0127] R １０１Examples of the substituent that the fused cyclic group in the formula (I) may have include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an aromatic hydrocarbon group, an alicyclic hydrocarbon group, etc. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group can be selected from the group consisting of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group described above in R １０１ Examples of the aromatic hydrocarbon group as a substituent of the fused cyclic group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.), and heterocyclic groups represented by the above chemical formulas (r-hr-1) to (r-hr-6). Examples of the alicyclic hydrocarbon group as a substituent of the fused cyclic group include a group in which one hydrogen atom has been removed from a monocycloalkane such as cyclopentane or cyclohexane; adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ a group in which one hydrogen atom has been removed from a polycycloalkane such as decane or tetracyclododecane; a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7) described below; a —SO 2 group represented by each of the general formulae (b5-r-1) to (b5-r-4) above, ２ -containing cyclic group: heterocyclic groups represented by the above chemical formulas (r-hr-7) to (r-hr-16), respectively.

[0128] A chain alkyl group which may have a substituent: R １０１The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0129] A chain alkenyl group which may have a substituent: R １０１ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the above chain alkenyl groups, a linear alkenyl group is preferred, a vinyl group or a propenyl group is more preferred, and a vinyl group is particularly preferred.

[0130] R １０１ Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the R １０１ Examples of the cyclic groups include the cyclic groups shown in the formula:

[0131] R １０１ is preferably a cyclic group which may have a substituent, more preferably an aromatic hydrocarbon group which may have a substituent, still more preferably a group in which one hydrogen atom has been removed from an aromatic ring which may have a substituent, and particularly preferably an aryl group.

[0132] In the formula (b-an-1), Y １０１is a single bond or a divalent linking group containing an oxygen atom. １０１ is a divalent linking group containing an oxygen atom, １０１ may contain an atom other than an oxygen atom. Examples of atoms other than an oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom. Examples of the divalent linking group containing an oxygen atom include linking groups represented by the following general formulas (L-a1-1) to (L-a1-8). In the following general formulas (L-a1-1) to (L-a1-8), R in the above formula (b-an-1) １０１ and V' in the following general formulae (L-al-1) to (L-al-8) １０１ is.

[0133] [In the formula, V' １０１ is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' １０２ is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0134] 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.

[0135] V' １０１ and V' １０２ The alkylene group in V' may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group. １０１ and V' １０２ Specific examples of the alkylene group in ２ -]; -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; ethylene groups [-CH ２ CH ２ -]; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, etc.; a trimethylene group (n-propylene group) [—CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ an alkyltrimethylene group such as -; a tetramethylene group [-CH ２ CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, etc.; an alkyltetramethylene group such as a pentamethylene group [—CH ２ CH ２ CH ２ CH ２ CH ２ -]. Also, V' １０１ or V' １０２Some methylene groups in the alkylene group in the formula (I) may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is preferably a divalent group in which one hydrogen atom has been removed from a cyclic aliphatic hydrocarbon group (a monocyclic aliphatic hydrocarbon group or a polycyclic aliphatic hydrocarbon group), and more preferably a cyclohexylene group, a 1,5-adamantylene group, or a 2,6-adamantylene group.

[0136] In the formula (b-an-1), V １０１ is a single bond, an alkylene group or a fluorinated alkylene group. １０１ is preferably a single bond or a linear fluorinated alkylene group having 1 to 4 carbon atoms.

[0137] In the formula (b-an-1), R １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０２ is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

[0138] Specific examples of the anion moiety represented by the formula (b-an-1) include, for example, Y １０１ When Y is a single bond, examples of the anion include a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion or a perfluorobutanesulfonate anion; １０１ When is a divalent linking group containing an oxygen atom, examples of the anion include anions represented by any one of the following general formulae (an-1) to (an-3).

[0139] [In the formula, R” １０１ R" is an aliphatic cyclic group which may have a substituent, a monovalent heterocyclic group represented by each of the above chemical formulas (r-hr-1) to (r-hr-16), a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), a chain alkyl group which may have a substituent, or an aromatic cyclic group which may have a substituent. １０２represents 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 below-described general formulas (a2-r-1), (a2-r-3) to (a2-r-7), or —SO ２ -containing cyclic group. １０３ V" is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. １０１ is a single bond, an alkylene group having 1 to 4 carbon atoms, or a fluorinated alkylene group having 1 to 4 carbon atoms. 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.

[0140] R” １０１ , R” １０２ and R” １０３ The aliphatic cyclic group which may have a substituent is represented by R １０１ The substituent is preferably a group exemplified as the cyclic aliphatic hydrocarbon group in the formula (b-an-1). １０１ Examples of the substituents that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1) include the same as those that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1).

[0141] R” １０１ and R” １０３ The aromatic cyclic group which may have a substituent in the formula (b-an-1) is R １０１ The substituent is preferably a group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in formula (b-an-1). １０１ Examples of the substituents that may substitute the aromatic hydrocarbon group in the above formula (1) include the same as those in the above formula (1).

[0142] R” １０１ The chain alkyl group which may have a substituent in the formula (b-an-1) is R １０１ R" is preferably a group exemplified as a chain alkyl group in １０３The chain alkenyl group which may have a substituent in the formula (b-an-1) is R １０１ Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0143] Regarding the anion in the component (d1-2), the anion represented by the general formula (d1-an-2) is: 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 １０１ However, Rd ２ In the formula (d1-an-2), the carbon atom adjacent to the S atom is not bonded to a fluorine atom (is not substituted with fluorine), and this makes the anion represented by general formula (d1-an-2) an appropriately weak acid anion, thereby improving the quenching ability to control the diffusion of acid.

[0144] Rd ２ is preferably a chain alkyl group which may have a substituent or an aliphatic cyclic group which may have a substituent, and more preferably an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 3 to 10 carbon atoms. Examples of the aliphatic cyclic group include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ ] a group (which may have a substituent) in which one or more hydrogen atoms have been removed from decane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor is more preferred.

[0145] Rd ２ The substituents that the cyclic group, chain alkyl group, and chain alkenyl group in １０１ Examples of the substituents include the same as those that the cyclic group, chain alkyl group and chain alkenyl group in the above may have.

[0146] Preferred specific examples of the anion represented by general formula (d1-an-2) are shown below.

[0147]

[0148] Y ＡＮ － When is a carboxylate anion, the anion moiety in the ionic group (ii) is preferably an anion represented by the following general formula (d1-an-1):

[0149] [In the formula, Rd １ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0150] Regarding the anion represented by the general formula (d1-an-1), in the formula (d1-an-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, and １０１ Among these, Rd １ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxy group, an oxo group, an alkyl group, an aryl group, an iodine atom, a bromine atom, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7) described below, an ether bond, an ester bond, an alkylene group, or a combination thereof.

[0151] Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (a polycyclic structure consisting of a bicyclooctane skeleton and another ring structure). Suitable examples of the aliphatic cyclic group include adamantane, norbornane, isobornane, tricyclo[5.2.1.0], ２，６

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

[0152] Preferred specific examples of the anion represented by general formula (d1-an-1) are shown below.

[0153]

[0154] Specific examples of the group represented by formula (I-1) are listed below: ２ is the ionic group (ii), the brackets [ ] in the formula indicate a terminal structure of the polymer main chain.

[0155]

[0156]

[0157] For the hydrocarbon group (iii): R ２ The hydrocarbon group (iii) in R is a hydrocarbon group having at least an iodine atom as a substituent. ２ The hydrocarbon group in R may be a cyclic group, a chain alkyl group, or a chain alkenyl group. １０１ Examples of the cyclic group, chain alkyl group, and chain alkenyl group in R ２ The hydrocarbon group in may have a substituent other than an iodine atom, and the substituent may be any of the above-mentioned R １０１ Examples of the substituents include the same as those that may be contained in the cyclic group, chain alkyl group, and chain alkenyl group in the above.

[0158] R ２The hydrocarbon group (iii) in the formula (I) is preferably a cyclic group having at least an iodine atom as a substituent, more preferably an aromatic group having at least an iodine atom as a substituent, still more preferably a group in which one hydrogen atom has been removed from an aromatic ring having at least an iodine atom as a substituent, and particularly preferably an aryl group (e.g., a phenyl group, a naphthyl group, etc.) having at least an iodine atom as a substituent. For example, when the aromatic ring is benzene, the number of iodine atoms bonded to the benzene may be 1 to 3, and from the viewpoints of sensitivity or exposure latitude, 2 or 3 is preferred, and 3 is more preferred. From the viewpoint of reducing roughness, 1 or 2 is preferred, and 2 is more preferred.

[0159] Specific examples of the group represented by formula (I-1) are listed below: ２ Specific examples where is a hydrocarbon group (iii) are shown below: In the formula, [ ] indicates a terminal structure of the polymer main chain.

[0160]

[0161] The component (A1-0) may be any polymer having a group represented by general formula (I-1) above (hereinafter sometimes referred to as "terminal group (I-1)") at at least one end of its main chain, and with respect to the structure aside from this terminal group (I-1), the same structure as that of the resin component (base resin) typically used as the base component for chemically amplified resists can be used. Such a component (A1-0) is preferably one that has a structural unit (a1) that includes an acid-decomposable group whose polarity increases under the action of acid. A preferred component (A1-0) may further contain other structural units as necessary in addition to the structural unit (a1).

[0162] <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 component (A1-0) preferably includes the structural unit (a1).

[0163] Examples of the acid-dissociable group include those that have been proposed as acid-dissociable groups for base resins of chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed as acid-dissociable groups for base resins of chemically amplified resist compositions include the "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," "tertiary alkyloxycarbonyl acid-dissociable groups," and "secondary alkyloxycarbonyl acid-dissociable groups" described below.

[0164] Acetal-Type Acid-Dissociable Group: Among the polar groups, examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter, sometimes referred to as "acetal-type acid-dissociable group"):

[0165] [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.]

[0166] In formula (a1-r-1), Ra' １ and Ra' ２ Among Ra', at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. １ or Ra' ２ When is an alkyl group, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester above, and alkyl groups having 1 to 5 carbon atoms are preferred. Specific examples include linear or branched alkyl groups. More specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. A methyl group or an ethyl group is more preferred, and a methyl group is particularly preferred.

[0167] In formula (a1-r-1), Ra' ３Examples of the hydrocarbon group include a linear or branched alkyl group, and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0168] The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0169] 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. As an aliphatic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an aliphatic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ ]decane, tetracyclododecane, and the like.

[0170] Ra' ３When the cyclic hydrocarbon group described above becomes an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Ra' ３ Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (an aryl group or a heteroaryl group); a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0171] Ra' ３ The cyclic hydrocarbon group in may have a substituent. Examples of the substituent include -RP1, -RP2-O-RP1, -RP2-CO-RP1, -RP2-CO-ORP1, -RP2-O-CO-RP1, -RP2-OH, -RP2-CN, and -RP2-COOH (hereinafter, these substituents are also collectively referred to as "Rax5"). Ｐ１is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ２ is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ１ and R 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 one type of the above-mentioned substituents, or may have one or more of each of two or more types of the above-mentioned substituents. Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, and cyclododecyl; and polycyclic aliphatic saturated hydrocarbon groups such as bicyclo[2.2.2]octanyl, tricyclo[5.2.1.02,6]decanyl, tricyclo[3.3.1.13,7]decanyl, tetracyclo[6.2.1.13,6.02,7]dodecanyl, and adamantyl. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene.

[0172] Ra' ３ But Ra' １ , Ra' ２ When the cyclic group is bonded to any one of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0173] Tertiary alkyl ester acid-dissociable group: Among the above polar groups, examples of the acid-dissociable group protecting the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2): Of the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group will hereinafter be referred to as "tertiary alkyl ester acid-dissociable groups" for convenience.

[0174] [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.

[0175] Ra' ４ Examples of the hydrocarbon group of Ra' include a linear or branched alkyl group, a linear or cyclic alkenyl group, and a cyclic hydrocarbon group. ４ The linear or branched alkyl group and the cyclic hydrocarbon group (a monocyclic aliphatic hydrocarbon group, a polycyclic aliphatic hydrocarbon group, and an aromatic hydrocarbon group) in ３ The same as Ra' can be mentioned. ４ The chain or cyclic alkenyl group in Ra' is preferably an alkenyl group having 2 to 10 carbon atoms. ５ , Ra' ６ The hydrocarbon group of Ra' ３ The same can be mentioned.

[0176] Ra' ５ and Ra' ６ When Ra' is bonded to each other to form a ring, preferred examples thereof include a group represented by the following general formula (a1-r2-1), a group represented by the following general formula (a1-r2-2), and a group represented by the following general formula (a1-r2-3). ４ ~Ra' ６ When the groups are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0177] [In formula (a1-r2-1), Ra' １０represents a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. １１ is Ra' １０ represents a group which forms an aliphatic cyclic group together with the carbon atom to which it is bonded. In formula (a1-r2-2), Ya is a carbon atom. Xa is a group which forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Ra １０１ ~Ra １０３ are each independently a hydrogen atom, a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent cyclic aliphatic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms in the linear saturated hydrocarbon group and the cyclic aliphatic saturated hydrocarbon group may be substituted. １０１ ~Ra １０３ Two or more of the above may be bonded to each other to form a cyclic structure. In formula (a1-r2-3), Yaa is a carbon atom. Xaa is a group that forms an aliphatic cyclic group together with Yaa. Ra １０４ In formula (a1-r2-4), Ra′ is an aromatic hydrocarbon group which may have a substituent. １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms of this chain saturated hydrocarbon group may be substituted. １４ is a hydrocarbon group which may have a substituent. * indicates a bond (the same applies hereinafter).

[0178] In the above formula (a1-r2-1), Ra' １０ is a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group.

[0179] Ra' １０ The linear alkyl group in Ra' has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. １０ In the formula (I), the branched alkyl group is the above-mentioned Ra' ３ The same can be mentioned.

[0180] Ra' １０ In the above, the alkyl group may be partially substituted with a halogen atom or a heteroatom-containing group. For example, some of the hydrogen atoms constituting the alkyl group may be substituted with a halogen atom or a heteroatom-containing group. Furthermore, some of the carbon atoms (such as methylene groups) constituting the alkyl group may be substituted with a heteroatom-containing group. Examples of the heteroatom include an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the heteroatom-containing group include (-O-), -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -S-, and -S(=O) ２ -, -S(=O) ２ -O- and the like.

[0181] In formula (a1-r2-1), Ra' １１ (Ra' １０ The aliphatic cyclic group formed together with the carbon atom to which Ra' is bonded in formula (a1-r-1) is ３ Among these, monocyclic alicyclic hydrocarbon groups are preferred, and specifically, cyclopentyl and cyclohexyl groups are more preferred.

[0182] In the formula (a1-r2-2), the cyclic hydrocarbon group formed by Xa together with Ya includes Ra' in the formula (a1-r-1). ３ Examples of the cyclic hydrocarbon group include a group in which one or more hydrogen atoms have been further removed from the cyclic monovalent hydrocarbon group (aliphatic hydrocarbon group) in the formula (I). The cyclic hydrocarbon group formed by Xa together with Ya may have a substituent. Examples of the substituent include the above-mentioned Ra' ３ In formula (a1-r2-2), the substituents that the cyclic hydrocarbon group in formula (a1-r2-2) may have are the same as those in formula (a1-r2-2). １０１ ~Ra １０３ In the formula, examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. １０１ ~Ra １０３In the above formula, examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group; ２，６ ]decanyl group, tricyclo[3.3.1.1 ３，７ ] decanyl group, tetracyclo[6.2.1.1 ３，６ .0 ２，７ ] and polycyclic aliphatic saturated hydrocarbon groups such as a dodecanyl group and an adamantyl group. １０１ ~Ra １０３ Among these, from the viewpoint of ease of synthesis, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferable, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferable, and a hydrogen atom is particularly preferable.

[0183] The above Ra １０１ ~Ra １０３ Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula (I) include the above-mentioned Ra ｘ５ The same groups as those shown below can be mentioned.

[0184] Ra １０１ ~Ra １０３ Examples of the group containing a carbon-carbon double bond formed by two or more of the above being bonded to each other to form a cyclic structure include a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclohexenyl group, a cyclopentylidene-ethenyl group, a cyclohexylidene-ethenyl group, etc. Among these, from the viewpoint of ease of synthesis, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred.

[0185] In formula (a1-r2-3), the aliphatic cyclic group formed by Xaa together with Yaa is Ra' in formula (a1-r-1). ３ In formula (a1-r2-3), the groups exemplified as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups. １０４Examples of the aromatic hydrocarbon group in the formula (I) include a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 5 to 30 carbon atoms. １０４ is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from benzene or naphthalene, and most preferably a group in which one or more hydrogen atoms have been removed from benzene.

[0186] Ra in formula (a1-r2-3) １０４ Examples of the substituent that may be possessed by the group include a methyl group, an ethyl group, a propyl group, a hydroxy group, a carboxy group, a halogen atom, an alkoxy group (e.g., a methoxy group, an ethoxy group, a propoxy group, a butoxy group), an alkyloxycarbonyl group, and the like.

[0187] In formula (a1-r2-4), Ra' １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. １２ and Ra' １３ In the formula (I), the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Ra １０１ ~Ra １０３ The monovalent saturated chain hydrocarbon group having 1 to 10 carbon atoms in the formula (1) may be substituted in part or in whole. １２ and Ra' １３ Among these, Ra' is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group. １２ and Ra' １３ In the case where the chain saturated hydrocarbon group represented by the formula: ｘ５ The same groups as those shown below can be mentioned.

[0188] In formula (a1-r2-4), Ra' １４is 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.

[0189] Ra' １４ The linear alkyl group in the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0190] Ra' １４ The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, and more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0191] Ra' １４ When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. As an aliphatic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an aliphatic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 ２，６ ]decane, tetracyclododecane, and the like.

[0192] Ra' １４ As the aromatic hydrocarbon group in １０４ Among them, the aromatic hydrocarbon groups Ra' are the same as those in １４is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from naphthalene or anthracene, and most preferably a group in which one or more hydrogen atoms have been removed from naphthalene. １４ Examples of the substituent that may be possessed by Ra include １０４ Examples of the substituents include the same as those that may be possessed by the group.

[0193] Ra' in formula (a1-r2-4) １４ When Ra' in formula (a1-r2-4) is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. １４ When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be any one of the 1st, 2nd, and 9th positions of the anthryl group.

[0194] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0195]

[0196]

[0197]

[0198] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0199]

[0200]

[0201]

[0202] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0203]

[0204] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0205]

[0206] Tertiary alkyloxycarbonyl acid dissociable group: Examples of the acid dissociable group that protects the hydroxyl group of the polar group include acid dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience, may be referred to as "tertiary alkyloxycarbonyl acid dissociable group").

[0207] [In the formula, Ra' ７ ~Ra' ９ are each an alkyl group.

[0208] In formula (a1-r-3), Ra' ７ ~Ra' ９ are each preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. The total number of carbon atoms in each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

[0209] Secondary Alkyl Ester-Type Acid-Dissociable Group: Among the above polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-4).

[0210] [In the formula, Ra' １０ is a hydrocarbon group. １１ａ and Ra' １１ｂ are each independently a hydrogen atom, a halogen atom or an alkyl group. １２ is a hydrogen atom or a hydrocarbon group. １０ and Ra' １１ａ or Ra' １１ｂ and may be bonded to each other to form a ring. １１ａ or Ra' １１ｂ and Ra' １２ may be bonded to each other to form a ring.

[0211] In the formula, Ra' １０ and Ra' １２The hydrocarbon group in Ra' is ３ In the formula, Ra' １１ａ and Ra' １１ｂ The alkyl group in Ra' is １ In the formula, Ra' is the same as the alkyl group in １０ and Ra' １２ and the hydrocarbon group in Ra' １１ａ and Ra' １１ｂ The alkyl group in may have a substituent. Examples of the substituent include the above-mentioned Ra ｘ５ etc.

[0212] Ra' １０ and Ra' １１ａ or Ra' １１ｂ may be bonded to each other to form a ring. The ring may be polycyclic or monocyclic, and may be an alicyclic or aromatic ring. The alicyclic and aromatic rings may contain heteroatoms.

[0213] Ra' １０ and Ra' １１ａ or Ra' １１ｂ and are bonded to each other to form a ring, among the above, a monocycloalkene, a ring in which a portion of the carbon atoms of a monocycloalkene is substituted with a heteroatom (such as an oxygen atom or a sulfur atom), or a monocycloalkadiene is preferred, a cycloalkene having 3 to 6 carbon atoms is preferred, and cyclopentene or cyclohexene is preferred.

[0214] Ra' １０ and Ra' １１ａ or Ra' １１ｂ The ring formed by bonding these may be a fused ring. Specific examples of such fused rings include indan.

[0215] Ra' １０ and Ra' １１ａ or Ra' １１ｂ The ring formed by bonding together may have a substituent. Examples of the substituent include the above-mentioned Ra ｘ５ etc.

[0216] Ra' １１ａor Ra' １１ｂ and Ra' １２ and may be bonded to each other to form a ring, and the ring may include Ra' １０ and Ra' １１ａ or Ra' １１ｂ and the ring formed by bonding with each other are exemplified.

[0217] Specific examples of the group represented by the formula (a1-r-4) are listed below.

[0218]

[0219] Examples of the structural unit (a1) include a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, a structural unit derived from acrylamide, a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least some of the hydrogen atoms in the hydroxyl groups are protected with a substituent containing the above-mentioned acid-decomposable group, and a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative in which at least some of the hydrogen atoms in -C(═O)-OH are protected with a substituent containing the above-mentioned acid-decomposable group.

[0220] Of the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Preferred specific examples of such structural unit (a1) include structural units represented by the following general formulas (a1-1), (a1-2), and (a1-3):

[0221] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １ is a divalent hydrocarbon group which may have an ether bond. ａ１ is an integer from 0 to 2. １ is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). １ is (n ａ２ +1) valent hydrocarbon group. ａ２ is an integer from 1 to 3.２ represents an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3). ００１ represents a single bond or a divalent linking group. ０１ is a single bond or a divalent linking group. ０１ is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). ０１ is an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group; q is an integer of 0 to 3; and n is an integer of 0 or greater, provided that n≦q×2+4.

[0222] In the formulas (a1-1) to (a1-3), the alkyl group having 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. A fluorine atom is particularly preferred as the halogen atom. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the perspective of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0223] In the formula (a1-1), Va １ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0224] Va １ The aliphatic hydrocarbon group as the divalent hydrocarbon group in may be saturated or unsaturated, and is usually preferably saturated. More specific examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0225] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0226] Examples of the aliphatic hydrocarbon group containing a ring in its structure include alicyclic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as the linear aliphatic hydrocarbon group or the branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. A preferred monocyclic alicyclic hydrocarbon group is a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ]decane, tetracyclododecane, and the like.

[0227] Va １The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such an aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (an arylene group); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (an aryl group) has been substituted with an alkylene group (for example, a group in which one further hydrogen atom has been removed from the aryl group of an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0228] In the formula (a1-1), Ra １ is preferably an acid-dissociable group represented by the above general formula (a1-r-2) or (a1-r-4), and among these, a group represented by the general formula (a1-r2-1) or an acid-dissociable group represented by the general formula (a1-r-4) is more preferred.

[0229] In the formula (a1-2), Wa １ (n ａ２The (+1)-valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in the structure, and groups that combine linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in the structure. ａ２ The valence of Ra is preferably 2 to 4, more preferably 2 or 3. ２ is preferably an acid-dissociable group represented by the above general formula (a1-r-1).

[0230] In the formula (a1-3), Ya ００１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ００１ is preferably an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Among these, Ya ００１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0231] In the formula (a1-3), Ya ０１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ０１Among the above, it is preferable that Ya is an ester bond [—C(═O)—O—, —O—C(═O)—], an ether bond (—O—), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. ０１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0232] In the formula (a1-3), Rax ０１ is preferably an acid dissociable group represented by the above general formula (a1-r-2) or (a1-r-4), and among these, an acid dissociable group represented by the general formula (a1-r-2) is more preferred, and a group represented by the general formula (a1-r2-1) is even more preferred.

[0233] In the formula (a1-3), Rz ０１ The alkyl group, halogenated alkyl group, and alkoxy group in Rz preferably have 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, even more preferably 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms. The alkyl group, halogenated alkyl group, and alkoxy group may be linear or branched. ０１ The halogen atom in Rz is preferably an iodine atom. ０１ The halogen atom of the halogenated alkyl group in Rz is preferably a fluorine atom, an iodine atom, or a bromine atom, and more preferably a fluorine atom. ０１ As the alkyl group, an alkoxy group or a hydroxy group is preferred, and a hydroxy group is more preferred.

[0234] In the formula (a1-3), q is an integer of 0 to 3. When q is 0, the structure is a benzene structure, when q is 1, the structure is a naphthalene structure, when q is 2, the structure is an anthracene structure, and when q is 3, the structure is a tetracene structure. In the formula (a1-3), n is an integer of 0 or more, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, and even more preferably 1 or 2. When n is an integer of 2 or more, Rz is 2 or more. ０１may be the same or different. In the formula (a1-3), n≦q×2+4. For example, when q is 1 and the naphthalene structure is formed, all six hydrogen atoms of the naphthalene are Rz ０１ In addition, in the naphthalene, Ya ００１ , -Ya ０１ -C(=O)-O-Rax ０１ group, and Rz ０１ The substitution position of is not particularly limited.

[0235] Specific examples of the structural unit (a1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0236]

[0237]

[0238]

[0239]

[0240]

[0241]

[0242]

[0243]

[0244]

[0245] In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. Rz represents a hydrogen atom, an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group.

[0246]

[0247]

[0248]

[0249]

[0250]

[0251] As the structural unit (a1), a structural unit represented by the formula (a1-1) or a structural unit represented by the formula (a1-3) is more preferred because these structural units are more likely to provide improved properties (sensitivity, shape, etc.) in electron beam or EUV lithography. Among these, an acid-dissociable group (Ra １ , Rax ０１ ) are preferably acid-dissociable groups represented by the above general formula (a1-r2-1), (a1-r2-3), (a1-r2-4) or (a1-r-4), respectively, and among these, it is particularly preferable to select those which are cyclic groups.

[0252] Alternatively, the structural unit (a1) may include a structural unit represented by the following general formula (a1-1-1):

[0253] [In the formula, Ra １ " is an acid-dissociable group represented by general formula (a1-r2-1), (a1-r2-3), (a1-r2-4) or (a1-r-4). * represents a bond.]

[0254] In the formula (a1-1-1), R, Va １ and n ａ１ represents R, Va in the formula (a1-1). １ and n ａ１ is the same as:

[0255] The acid-dissociable group represented by general formula (a1-r2-1), (a1-r2-3), (a1-r2-4), or (a1-r-4) is as described above. Among these, it is preferable to select an acid-dissociable group that is a cyclic group, as this is suitable for use with EB or EUV and can enhance reactivity.

[0256] The structural unit (a1) contained in the component (A1-0) may be of one type, or may be of two or more types. The proportion of the structural unit (a1) in the component (A1-0), relative to the total (100 mol%) of all structural units constituting the component (A1-0), is preferably 5 to 80 mol%, more preferably 10 to 75 mol%, even more preferably 30 to 70 mol%, and particularly preferably 40 to 70 mol%. By ensuring that the proportion of the structural unit (a1) is at least the lower limit of the above-mentioned preferred range, lithography properties such as sensitivity, roughness, exposure latitude, and resolution are improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0257] <<Other Structural Units>> The preferred component (A1-0) may contain, in addition to the above-mentioned structural unit (a1), other structural units as necessary. Examples of such other structural units include the structural unit (a10) represented by general formula (a10-1) described below, a structural unit (a2) containing a lactone-containing cyclic group, a structural unit (a5) that generates acid upon exposure, a structural unit (a6) that has acid diffusion-controlling properties, and a structural unit (a8) derived from a compound represented by general formula (a8-1) described below.

[0258] Regarding the structural unit (a10) represented by general formula (a10-1): The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0259] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ｘ１ is a single bond or a divalent linking group. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ is an integer of 1 or greater.

[0260] In the formula (a10-1), R is the same as R in the general formula (a1-1). R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is particularly preferred.

[0261] In the formula (a10-1), Ya ｘ１ is a single bond or a divalent linking group. ｘ１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0262] Divalent hydrocarbon group which may have a substituent: The divalent hydrocarbon group which may have a substituent may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0263] Aliphatic hydrocarbon group: An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups that contain a ring in their structure.

[0264] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched chain aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched chain aliphatic hydrocarbon group, a branched chain alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0265] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0266] ...Aliphatic hydrocarbon groups containing a ring in their structure. Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ]decane, tetracyclododecane, and the like.

[0267] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and even more preferably a methoxy group or an ethoxy group. The halogen atom as the substituent is preferably a fluorine atom. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0268] Aromatic Hydrocarbon Group The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0269] In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include those exemplified as the substituent substituting a hydrogen atom of the cyclic aliphatic hydrocarbon group.

[0270] Divalent linking group containing a hetero atom: Examples of the divalent linking group containing a hetero atom include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, and -S(=O). ２ -, -S(=O) ２ -O-, general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O) ２ -O-Y ２２ -, wherein Y ２１ and Y ２２are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m" is an integer of 1 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. In the general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O) ２ -O-Y ２２ -Middle, Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as those described above. ２１ As Y, a linear aliphatic hydrocarbon group is preferred, a linear alkylene group is more preferred, a linear alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or an ethylene group is particularly preferred. ２２ is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. ２１ -C(=O)-O] ｍ” -Y ２２ In the group represented by -, m" is an integer of 1 to 3, preferably 1 or 2, and more preferably 1. That is, the group represented by the formula -[Y ２１ -C(=O)-O] ｍ”-Y ２２ The group represented by - includes the group represented by the formula -Y ２１ -C(=O)-O-Y ２２ Among them, groups represented by the formula -(CH ２ ) ａ’ -C(=O)-O-(CH ２ ) ｂ’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0271] Ya ｘ１ is preferably a single bond, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -O-C(=O)-].

[0272] In the formula (a10-1), Wa ｘ１ is an aromatic hydrocarbon group which may have a substituent. ｘ１ The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ａｘ１ Examples of the aromatic ring include a group in which 4n+1) hydrogen atoms have been removed. The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Wa ｘ１The aromatic hydrocarbon group in (n) is selected from aromatic compounds containing an aromatic ring which may have two or more substituents (for example, biphenyl, fluorene, etc.). ａｘ１ Also included are groups in which one or more hydrogen atoms have been removed. ｘ１ Examples of the aryl group include benzene, naphthalene, anthracene, and biphenyl (n ａｘ１ A group in which (n +1) hydrogen atoms have been removed is preferred, and a group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ａｘ１ A group in which (n +1) hydrogen atoms have been removed from benzene is more preferred, ａｘ１ A group in which 1) hydrogen atoms have been removed is more preferred.

[0273] Wa ｘ１ The aromatic hydrocarbon group in may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl group. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include Ya ｘ１ Examples of the substituent include the same as those exemplified as the substituent of the cyclic aliphatic hydrocarbon group in Wa. 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.

[0274] In the formula (a10-1), n ａｘ１ is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0275] Specific examples of the structural unit (a10) represented by the formula (a10-1) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0276]

[0277]

[0278]

[0279] The structural unit (a10) contained in the component (A1-0) may be one type, or two or more types. The component (A1-0) may or may not contain the structural unit (a10), but it is preferable that the component (A1-0) contain the structural unit (a10). When the component (A1-0) contains the structural unit (a10), the proportion of the structural unit (a10) in the component (A1-0) is preferably 20 to 80 mol%, more preferably 25 to 70 mol%, even more preferably 30 to 60 mol%, and particularly preferably 30 to 50 mol%, based on the total (100 mol%) of all structural units constituting the component (A1-0). By ensuring that the proportion of the structural unit (a10) is at least the lower limit of the above-mentioned preferred range, sensitivity is likely to be further improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, it is easier to achieve a balance with the other structural units.

[0280] Regarding the structural unit (a2) containing a lactone-containing cyclic group: The component (A1-0) may or may not contain a structural unit (a2) containing a lactone-containing cyclic group (provided that this does not correspond to the structural unit (a1)). When the component (A1-0) is used to form a resist film, the lactone-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate. Furthermore, the presence of the structural unit (a2) results in favorable lithography properties due to effects such as appropriately adjusting the acid diffusion length, improving the adhesion of the resist film to the substrate, and appropriately adjusting the solubility during development.

[0281] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) that contains -O-C(=O)- within its ring skeleton. The lactone ring is counted as the first ring, and when there is only a lactone ring, it is called a monocyclic group, and when there is also another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. There are no particular restrictions on the lactone-containing cyclic group in the structural unit (a2), and any group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0282] [In the formula, Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, or a lactone-containing cyclic group; A″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), an oxygen atom, or a sulfur atom; n′ is an integer of 0 to 2, and m′ is 0 or 1. * represents a bond (the same applies hereinafter).

[0283] In the general formulas (a2-r-1) to (a2-r-7), Ra' ２１ The alkyl group in Ra' is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Of these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' ２１ The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, ２１ Examples of the alkyl groups include those mentioned as examples of the alkyl group in the above formula and an oxygen atom (—O—). ２１ The halogen atom in Ra' is preferably a fluorine atom. ２１ As the halogenated alkyl group in the formula Ra′, ２１ Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0284] Ra' ２１In -COOR" and -OC(=O)R" in the formula (I), R" is either a hydrogen atom, an alkyl group, or a lactone-containing cyclic group. The alkyl group for R" may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R" is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably has 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably has 4 to 12 carbon atoms, and most preferably has 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specifically, groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; ２，６ ] decane, tetracyclododecane, and other polycycloalkanes in which one or more hydrogen atoms have been removed. Examples of the lactone-containing cyclic group in R" include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7). Ra' ２１ The hydroxyalkyl group in the formula (Ra') preferably has 1 to 6 carbon atoms. ２１ and a group in which at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0285] Ra' ２１ Among the above, each of the groups is preferably independently a hydrogen atom or a cyano group.

[0286] In the general formulae (a2-r-2), (a2-r-3), and (a2-r-5), the alkylene group having 1 to 5 carbon atoms for A" is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include groups in which -O- or -S- is present at the terminal or between carbon atoms of the alkylene group, such as -O-CH ２ -, -CH ２ -O-CH ２ -, -S-CH ２ -, -CH ２ -S-CH ２ A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

[0287] Specific examples of the groups represented by general formulae (a2-r-1) to (a2-r-7) are listed below.

[0288]

[0289]

[0290] Of the structural units (a2), structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent are preferred. Such structural units (a2) are preferably structural units represented by the following general formula (a2-1):

[0291] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１ represents a single bond or a divalent linking group. ２１ represents -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. ２１ When is -O-, Ya ２１ does not become -CO-. ２１ is a lactone-containing cyclic group.

[0292] In the formula (a2-1), R is the same as defined above. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is particularly preferred.

[0293] In the formula (a2-1), Ya ２１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ２１ As the divalent linking group in the general formula (a10-1), ｘ１ Examples of the divalent linking group include the same as the divalent linking group in the above formula.

[0294] 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.

[0295] In the formula (a2-1), Ya ２１ is a single bond, and La ２１ is preferably —COO— or —OCO—.

[0296] In the formula (a2-1), Ra ２１ is a lactone-containing cyclic group. ２１ Suitable examples of the lactone-containing cyclic group in the formula (a2-r-1) include the groups represented by the general formulae (a2-r-1) to (a2-r-7) described above.

[0297] The structural unit (a2) contained in the component (A1-0) may be of one type, or may contain two or more types. The component (A1-0) may or may not contain the structural unit (a2). When the component (A1-0) contains the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 20 mol %, more preferably 1 to 15 mol %, and even more preferably 1 to 10 mol %, relative to the total (100 mol %) of all structural units constituting the component (A1-0). By ensuring that the proportion of the structural unit (a2) is at least the lower limit of the preferred range, the aforementioned effects achieved by including the structural unit (a2) can be fully obtained. On the other hand, by ensuring that the proportion is at most the upper limit of the preferred range, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0298] Regarding the structural unit (a5) that generates an acid upon exposure: The component (A1-0) may or may not include the structural unit (a5) that generates an acid upon exposure. A known structural unit can be used as the structural unit (a5). The structural unit (a5) makes it easier for the acid generated upon exposure to be uniformly distributed within the resist film. The structural unit (a5) makes it easier for the acid generated upon exposure to be uniformly distributed within the resist film. Examples of the structural unit (a5) include structural units containing a structure described below for the component (B). Examples include structural units containing a structure represented by any of the general formulas (b-1) to (b-3) described below. Suitable examples of the structural unit (a5) include structural units represented by the following general formula (a5-1):

[0299] [In the formula, R ｍ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. ５０ is a divalent linking group or a single bond. ５０ represents a divalent hydrocarbon group which may have a substituent. ａ５ is an integer from 0 to 2. ５１ is a divalent linking group. ５ is a divalent linking group which may have a heteroatom, or a single bond.５１ and Ra ５２ are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group, n5 is an integer of 1 to 4, m is an integer of 1 or more, and M' ｍ＋ is an m-valent onium cation.

[0300] {Anion moiety} In the formula (a5-1), R ｍ is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. ｍ The alkyl group having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. As the halogen atom in the halogenated alkyl group, a fluorine atom is particularly preferred. R ｍ As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms is preferred, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0301] In the formula (a5-1), La ５０ is a divalent linking group or a single bond. ５０ The divalent linking group in the formula (I) is not particularly limited, but a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom are preferred. ｘ１ The divalent linking group is the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom exemplified in the above. ５０is preferably an ester bond [—C(═O)—O—, —O—C(═O)—], an ether bond (—O—), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. ５ is more preferably an ester bond [—C(═O)—O—, —O—C(═O)—] or a single bond, and further preferably an ester bond [—C(═O)—O—, —O—C(═O)—].

[0302] In the formula (a5-1), Ra ５０ is a divalent hydrocarbon group which may have a substituent. ５０ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0303] .Ra ５０ The aliphatic hydrocarbon group in the above formula (1) means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0304] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0305] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0306] ...Aliphatic hydrocarbon groups containing a ring in their structure Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclo[5.2.1.0] ２，６ ]decane, tetracyclododecane, and the like.

[0307] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0308] .Ra ５０The aromatic hydrocarbon group in the above formula (1) is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0309] In the aromatic hydrocarbon group, a hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include those exemplified as the substituent that substitutes a hydrogen atom contained in the cyclic aliphatic hydrocarbon group.

[0310] In the formula (a5-1), n ａ５ is an integer of 0 to 2. Among the above, Ra ５０ is preferably an aliphatic hydrocarbon group containing a ring in its structure, more preferably a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure, and even more preferably an alicyclic hydrocarbon group which is a polycyclic group or a monocyclic group and may have a substituent. ５０ is preferably an aromatic hydrocarbon group.

[0311] n ａ５ If is 2, then two Ra ５０ may all be alicyclic hydrocarbon groups which may have a substituent, may all be aromatic hydrocarbon groups, or may be a combination of alicyclic hydrocarbon groups which may have a substituent and aromatic hydrocarbon groups.

[0312] In the formula (a5-1), La ５１ is a divalent linking group. ５１Examples of the divalent linking group in the formula (I) include non-hydrocarbon oxygen atom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an amide bond (-C(=O)-NH-), a carbonyl group (-C(=O)-), and a carbonate bond (-O-C(=O)-O-); and combinations of such non-hydrocarbon oxygen atom-containing linking groups with alkylene groups. These combinations may also be further combined with a sulfonyl group (-SO ２ Examples of such a divalent linking group include the linking groups represented by the following general formulae (L-al-1) to (L-al-8). In the following general formulae (L-al-1) to (L-al-8), Ra in the above formula (a5-1) may be ５０ and V' in the following general formulae (L-al-1) to (L-al-8) １０１ is.

[0313] [In the formula, V' １０１ is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' １０２ is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0314] 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.

[0315] V' １０１ and V' １０２ The alkylene group in V' may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group. １０１ and V' １０２ Specific examples of the alkylene group in ２ -]; -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; ethylene groups [-CH ２ CH ２ -]; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, etc.; a trimethylene group (n-propylene group) [—CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ an alkyltrimethylene group such as -; a tetramethylene group [-CH ２ CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, etc.; an alkyltetramethylene group such as a pentamethylene group [—CH ２ CH ２ CH ２ CH ２ CH ２ -]. Also, V' １０１ or V' １０２ In the formula (a1-r-1), some of the methylene groups in the alkylene group may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is represented by Ra' in the formula (a1-r-1).３ A divalent group obtained by removing one more hydrogen atom from a cyclic aliphatic hydrocarbon group (a monocyclic aliphatic hydrocarbon group or a polycyclic aliphatic hydrocarbon group) of the above formula (I) is preferred, and a cyclohexylene group, a 1,5-adamantylene group, or a 2,6-adamantylene group is more preferred.

[0316] La ５１ As the linking group, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, the linking groups represented by the above formulas (L-a1-1) to (L-a1-5) and (L-a1-8) are more preferable, and the linking group represented by the above formula (L-a1-3) or (L-a1-8) is even more preferable.

[0317] In the formula (a5-1), Ya ５ represents a divalent linking group which may have a heteroatom, or a single bond. ５ 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. ５ The divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in ｘ１ The divalent linking group is the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom exemplified in the above. ５ is preferably a linear or branched alkylene group or a single bond, and more preferably a single bond.

[0318] In the formula (a5-1), Ra ５１ and Ra ５２ are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group. ５１ and Ra ５２ In the formula (a5-1), the fluorinated alkyl group is preferably a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms, and more preferably a trifluoromethyl group. ３ － Ra bonded to the carbon atom adjacent to ５１ and Ra ５２From the viewpoint of acid strength, it is preferable that at least one of the groups is a fluorine atom.

[0319] In the formula (a5-1), n5 represents an integer of 1 to 4, and is preferably 1, 2, or 3.

[0320] {Cation moiety} In the formula (a5-1), M' ｍ＋ represents an m-valent onium cation. ｍ＋ is preferably a sulfonium cation or an iodonium cation, and m is an integer of 1 or more.

[0321] Preferred cationic moieties ((M' ｍ＋ ) １／ｍ ) includes organic cations represented by the above general formulas (ca-1) to (ca-3), respectively.

[0322] The cation moiety ((M' ｍ＋ ) １／ｍ As the cation represented by the formula (ca-1), a sulfonium cation is preferable, the cations represented by the formulas (ca-1) to (ca-3) are more preferable, the cation represented by the formula (ca-1) is even more preferable, and the cations represented by the formulas (ca-1-1) to (ca-1-84) are particularly preferable. In particular, from the viewpoint of increasing sensitivity, the preferred cation represented by the formula (ca-1) is preferably one having an electron-withdrawing group such as a fluorine atom, a fluorinated alkyl group, or a sulfonyl group as a substituent, and for example, a cation selected from the group consisting of the cations represented by the formulas (ca-1-44), (ca-1-71) to (ca-1-84) are particularly preferable.

[0323] Specific preferred examples of the structural unit (a5) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. ｍ＋ represents m and M' in the general formula (a5-1). ｍ＋ is the same as:

[0324]

[0325]

[0326]

[0327]

[0328] The structural unit (a5) contained in the component (A1-0) may be of one type, or may be of two or more types. When the component (A1-0) contains the structural unit (a5), the proportion of the structural unit (a5) in the component (A1-0) is preferably 5 to 25 mol %, more preferably 10 to 20 mol %, and even more preferably 15 to 20 mol %, based on the total (100 mol %) of all structural units constituting the component (A1-0). When the proportion of the structural unit (a5) is at least the lower limit of the above-mentioned preferred range, it becomes easier to achieve even higher sensitivity and improved resolution. On the other hand, when the proportion is at most the upper limit of the above-mentioned preferred range, it becomes easier to achieve a balance with the other structural units.

[0329] Regarding the structural unit (a6) having acid diffusion controllability: The structural unit (a6) is a structural unit that has acid diffusion controllability. The component (A1-0) may or may not have the structural unit (a6). Known structural units can be used as the structural unit (a6). Examples of the structural unit (a6) include structural units containing the structures described in the components (D1) and (D2) described below. Examples include structural units containing a structure represented by any of the general formulas (d1-1) to (d1-3) described below.

[0330] Specific preferred examples of the structural unit (a6) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. ｍ＋ represents m and M' in the general formula (a5-1). ｍ＋ is the same as:

[0331]

[0332] The structural unit (a6) contained in the component (A1-0) may be of one type, or may be of two or more types. When the component (A1-0) contains the structural unit (a6), the proportion of the structural unit (a6) in the component (A1-0) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total (100 mol %) of all structural units constituting the component (A1-0). When the proportion of the structural unit (a6) is at least the lower limit of the above-mentioned preferred range, it becomes easier to achieve even higher sensitivity. On the other hand, when the proportion is at most the upper limit of the above-mentioned preferred range, it becomes easier to achieve a balance with the other structural units.

[0333] Regarding the structural unit (a8) derived from a compound represented by general formula (a8-1): The structural unit (a8) is a structural unit derived from a compound represented by the following general formula (a8-1): The component (A1-0) may or may not include the structural unit (a8).

[0334] [In the formula, W ２ is a polymerizable group-containing group. ｘ２ is a single bond or (n ａｘ２ +1)valent linking group. ｘ２ and W ２ may form a condensed ring. １ is a fluorinated alkyl group having 1 to 12 carbon atoms. ２ R is a hydrogen atom or an organic group having 1 to 12 carbon atoms which may have a fluorine atom. ２ and Ya ｘ２ may be bonded to each other to form a ring structure. ａｘ２ is an integer from 1 to 3.

[0335] W ２ The "polymerizable group" in the polymerizable group-containing group is a group that enables a compound having a polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.

[0336] The polymerizable group-containing group may be a group composed of only a polymerizable group, or may be a group composed of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Examples of the polymerizable group-containing group include a group represented by the chemical formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０ In this chemical formula, R Ｘ１１ , R Ｘ１２ and R Ｘ１３ are each a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Ya ｘ０ is a single bond or a divalent linking group.

[0337] Ya ｘ２ and W ２ The fused ring formed by ２ The polymerizable group at the site and Ya ｘ２ and a fused ring formed by W ２ Other groups than the polymerizable group at the Ya ｘ２ and a fused ring formed by ｘ２ and W ２ The fused ring formed by these may have a substituent.

[0338] Specific examples of the structural unit (a8) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0339]

[0340] Among the above examples, the structural unit (a8) is preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), (a8-1-06), (a8-1-08), (a8-1-09), and (a8-1-10), and more preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), and (a8-1-09).

[0341] The structural unit (a8) contained in the component (A1-0) may be of one type, or may be of two or more types. The component (A1-0) may or may not contain the structural unit (a8). The proportion of the structural unit (a8) in the component (A1-0) is preferably 0 to 50 mol %, and more preferably 0 to 30 mol %, relative to the total (100 mol %) of all structural units constituting the component (A1-0).

[0342] The resist composition may contain one type of component (A1-0), or two or more types may be used in combination. In the resist composition of this embodiment, the component (A1-0) is a polymer that has a "terminal group (I-1)" at at least one end of its main chain, and examples include a polymeric compound that has the structural unit (a1) and the structural unit (a10) in addition to the terminal group (I-1), a polymeric compound that has the structural unit (a1), the structural unit (a10), and the structural unit (a5) in addition to the terminal group (I-1), a polymeric compound that has the structural unit (a1), the structural unit (a10), and the structural unit (a6) in addition to the terminal group (I-1), and a polymeric compound that has the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6) in addition to the terminal group (I-1). Preferred examples of the component (A1-0) include a polymeric compound that has the terminal group (I-1) and is composed of the structural unit (a1) and the structural unit (a10); a polymeric compound that has the terminal group (I-1) and is composed of the structural unit (a1), the structural unit (a10), and the structural unit (a5); a polymeric compound that has the terminal group (I-1) and is composed of the structural unit (a1), the structural unit (a10), and the structural unit (a6); and a polymeric compound that has the terminal group (I-1) and is composed of the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6).

[0343] For the component (A1-0), in a polymeric compound composed of the structural unit (a1) and the structural unit (a10), the proportion of the structural unit (a1) within the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%. The proportion of the structural unit (a10) within the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%.

[0344] For the component (A1-0), in a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a5), the proportion of the structural unit (a1) in the polymeric compound is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) in the polymeric compound is preferably 20 to 45 mol%, more preferably 25 to 45 mol%, and even more preferably 30 to 40 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a5) in the polymeric compound is preferably 5 to 30 mol%, more preferably 5 to 25 mol%, and even more preferably 10 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound.

[0345] For the component (A1-0), in a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a6), the proportion of the structural unit (a1) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, and even more preferably 45 to 55 mol%. The proportion of the structural unit (a10) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 29 to 55 mol%, more preferably 38 to 50 mol%, and even more preferably 42 to 50 mol%. The proportion of the structural unit (a6) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 1 to 15 mol%, more preferably 2 to 10 mol%, and even more preferably 3 to 5 mol%.

[0346] For the component (A1-0), in a polymeric compound composed of the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6), the proportion of the structural unit (a1) in the polymeric compound is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) in the polymeric compound is preferably 20 to 35 mol%, more preferably 23 to 40 mol%, and even more preferably 27 to 35 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a5) in the polymeric compound is preferably 4 to 25 mol%, more preferably 5 to 20 mol%, and even more preferably 10 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a6) in the polymer compound is preferably 1 to 15 mol %, more preferably 2 to 10 mol %, and even more preferably 3 to 5 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0347] Component (A1-0) can be produced, for example, by dissolving monomers from which each structural unit is derived in a polymerization solvent, adding a selected radical polymerization initiator such that at least one terminus of the main chain of the polymer becomes terminal group (I-1), and polymerizing the resulting mixture. Alternatively, component (A1-0) can be produced by dissolving a monomer from which structural unit (a1), a monomer from which structural unit (a10), and a monomer from which any structural unit (e.g., structural unit (a5), structural unit (a6), etc.) are derived in a polymerization solvent, adding a selected radical polymerization initiator such that at least one terminus of the main chain of the polymer becomes terminal group (I-1), polymerizing the resulting mixture, and then carrying out a deprotection reaction.

[0348] Within the resist composition of this embodiment, the component (A1-0) is preferably a radical polymer obtained by radical polymerization using a radical polymerization initiator that contains a compound represented by general formula (I) below (hereafter also referred to as “compound (I)”), because when used in a resist composition, high sensitivity is achieved, the effect of reducing roughness and the exposure latitude are all enhanced, and storage stability is also likely to be improved.

[0349] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. The plurality of R present in the formula １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different. N is a nitrogen atom.

[0350] In the formula (I), R １ , Z, X, R ２ represents R in the above formula (I-1). １ , Z, X, R ２ In addition, the plurality of R １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different from each other, but are preferably the same from an industrial standpoint.

[0351] Preferred examples of the compound (I) include compounds represented by the following formulas (I1) to (I8). ２ has the same meaning as above.

[0352]

[0353] Compound (I) is preferably selected from the group consisting of compounds represented by the formulas (I1) to (I8), and more preferably selected from the group consisting of compounds represented by the formulas (I1), (I7), and (I8). Specific examples of compound (I) are shown below.

[0354]

[0355]

[0356]

[0357]

[0358]

[0359]

[0360] The weight-average molecular weight (Mw) of component (A1-0) (based on polystyrene standards measured by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and even more preferably 5,000 to 30,000. When the Mw of component (A1-0) is equal to or less than the upper limit of the above-mentioned preferred range, the component has sufficient solubility in a resist solvent for use as a resist. On the other hand, when the Mw is equal to or greater than the lower limit of the above-mentioned preferred range, the component exhibits good dry etching resistance and a good resist pattern cross-sectional shape. The dispersity (Mw / Mn) of component (A1-0) is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.0 to 2.0. Here, Mn represents the number-average molecular weight.

[0361] Regarding the Component (A2): The component (A2) is a polymer (excluding those corresponding to the component (A1-0)) whose solubility in a developer changes under the action of acid. The components (A2) and (A1-0) differ at least in the structure of the terminal group at the end of the main chain. This component (A2) is preferably one that contains the structural unit (a1) described above that contains an acid-decomposable group whose polarity increases under the action of acid. A preferred component (A2) may contain, in addition to the structural unit (a1), other structural units as necessary. Examples of other structural units include the structural unit (a10), structural unit (a2), structural unit (a5), structural unit (a6), and structural unit (a8) described above.

[0362] The component (A2) contained in the resist composition may be used alone, or in combination with two or more different compounds. In the resist composition of this embodiment, examples of the component (A2) include a polymeric compound having the structural unit (a1) and the structural unit (a10), a polymeric compound having the structural unit (a1), the structural unit (a10), and the structural unit (a5), a polymeric compound having the structural unit (a1), the structural unit (a10), and the structural unit (a6), and a polymeric compound having the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6). Preferred examples of the component (A2) include a polymeric compound composed of the structural unit (a1) and the structural unit (a10), a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a5), a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a6), and a polymeric compound composed of the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6).

[0363] For the component (A2), in a polymeric compound composed of the structural unit (a1) and the structural unit (a10), the proportion of the structural unit (a1) within the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%. The proportion of the structural unit (a10) within the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%.

[0364] For the component (A2), in a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a5), the proportion of the structural unit (a1) in the polymeric compound is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) in the polymeric compound is preferably 20 to 45 mol%, more preferably 25 to 45 mol%, and even more preferably 30 to 40 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a5) in the polymeric compound is preferably 5 to 30 mol%, more preferably 5 to 25 mol%, and even more preferably 10 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound.

[0365] For the component (A2), in a polymeric compound composed of the structural unit (a1), the structural unit (a10), and the structural unit (a6), the proportion of the structural unit (a1) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, and even more preferably 45 to 55 mol%. The proportion of the structural unit (a10) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 29 to 55 mol%, more preferably 38 to 50 mol%, and even more preferably 42 to 50 mol%. The proportion of the structural unit (a6) in the polymeric compound, relative to the total (100 mol%) of all structural units constituting the polymeric compound, is preferably 1 to 15 mol%, more preferably 2 to 10 mol%, and even more preferably 3 to 5 mol%.

[0366] For the component (A2), in a polymeric compound composed of the structural units (a1), (a10), (a5), and (a6), the proportion of the structural unit (a1) within the polymeric compound is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) within the polymeric compound is preferably 20 to 35 mol%, more preferably 23 to 40 mol%, and even more preferably 27 to 35 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a5) within the polymeric compound is preferably 4 to 25 mol%, more preferably 5 to 20 mol%, and even more preferably 10 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the polymeric compound. The proportion of the structural unit (a6) in the polymer compound is preferably 1 to 15 mol %, more preferably 2 to 10 mol %, and even more preferably 3 to 5 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0367] Component (A2) can be produced by dissolving the monomers that derive each structural unit in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing. Alternatively, component (A2) can be produced by dissolving a monomer that derives structural unit (a1), a monomer that derives structural unit (a10), and a monomer that derives any structural unit (e.g., structural unit (a5), structural unit (a6), etc.) in a polymerization solvent, adding a radical polymerization initiator such as those described above to polymerize, and then carrying out a deprotection reaction. During the polymerization, for example, HS-CH ２ -CH ２ -CH ２ -C(CF ３ ) ２ By using a chain transfer agent such as —OH in combination, it is possible to obtain a chain with —C(CF ３ ) ２A copolymer having a hydroxyalkyl group in which some of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms is thus introduced, and is effective in reducing development defects and LER (line edge roughness: non-uniform irregularities on the line sidewalls).

[0368] The weight-average molecular weight (Mw) of component (A2) (based on polystyrene standards measured by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and even more preferably 5,000 to 30,000. When the Mw of component (A2) is equal to or less than the upper limit of the above-mentioned preferred range, the component has sufficient solubility in a resist solvent for use as a resist. On the other hand, when the Mw is equal to or greater than the lower limit of the above-mentioned preferred range, the component exhibits good dry etching resistance and a favorable cross-sectional shape of the resist pattern. The dispersity (Mw / Mn) of component (A2) is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.0 to 2.0. Here, Mn represents the number-average molecular weight.

[0369] In the resist composition of this embodiment, the component (A1) may consist solely of the component (A1-0), or may contain the component (A1-0) in combination with the component (A2). Within the component (A1), the proportion of the component (A1-0) relative to the total mass of the component (A1) is preferably 25 mass% or more, more preferably 50 mass% or more, and even more preferably 75 mass% or more, and may even be 100 mass%. When this proportion is 25 mass% or more, sensitivity, the effect of reducing roughness, and the exposure latitude are all likely to be improved, and the storage stability of the resist composition is also likely to be improved.

[0370] When the component (A1-0) and the component (A2) are used in combination, the mixing ratio of the two, expressed as the mass ratio of the component (A1-0) / the component (A2), is preferably from 25 / 75 to 90 / 10, more preferably from 50 / 50 to 85 / 15, and even more preferably from more than 50 / 50 to 80 / 20. When the mass ratio of the component (A1-0) / the component (A2) is within the above-mentioned preferred range, high sensitivity can be achieved, and both the effect of reducing roughness and the exposure latitude can be enhanced, and a resist composition with excellent storage stability can be easily prepared. Furthermore, when the mass ratio of the component (A1-0) / the component (A2) is at least the lower limit of the above-mentioned preferred range, it is possible to easily improve all of the sensitivity, the effect of reducing roughness, and the exposure latitude.

[0371] Regarding the component (A3): The resist composition of this embodiment may also use, as the component (A), a base component (A3) that does not fall under the category of the component (A1), and whose solubility in a developer changes under the action of acid. There are no particular limitations on the component (A3), and it may be selected from the many base components that are conventionally known for use in chemically amplified resist compositions.

[0372] 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.

[0373] <Other Components> The resist composition of this embodiment may further contain other components in addition to the component (A). Examples of other components include the following components (B), (D), (E), (F), and (S).

[0374] <Acid Generator Component (B)> The resist composition of this embodiment may further contain an acid generator component (B) that generates an acid upon exposure. The component (B) is not particularly limited, and any of the components that have been proposed as acid generators for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl- or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators. The component (B) may be contained in the form of a compound, or may be incorporated into the component (A1) as the structural unit (a5) described above, or may be in both of these forms.

[0375] Examples of the onium salt acid generator include a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), a compound represented by general formula (b-2) (hereinafter also referred to as "component (b-2)"), or a compound represented by general formula (b-3) (hereinafter also referred to as "component (b-3)"):

[0376] [In the formula, R １０１ and R １０４ ~R １０８ R are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. １０４ and R １０５ may be bonded to each other to form a ring structure. １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０１ is a divalent linking group containing an oxygen atom or a single bond. １０１ ~V １０３ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. １０１ and V １０１ cannot be a single bond at the same time. １０１ ~L １０２are each independently a single bond or an oxygen atom. １０３ ~L １０５ each independently represents a single bond, —CO— or —SO ２ m is an integer of 1 or more, and M' ｍ＋ is an m-valent onium cation.

[0377] {Anion moiety} Anion in component (b-1) In formula (b-1), R １０１ , Y １０１ , V １０１ and R １０２ represents R in the above general formula (b-an-1). １０１ , Y １０１ , V １０１ and R １０２ This is similar to the explanation for

[0378] Specific examples of the anion moiety represented by the formula (b-1) include, for example, Y １０１ When Y is a single bond, examples of the anion include a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion or a perfluorobutanesulfonate anion; １０１ When is a divalent linking group containing an oxygen atom, examples of the anion include those represented by any one of the above formulae (an-1) to (an-3).

[0379] Anion in component (b-2) In formula (b-2), R １０４ , R １０５ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R １０１ However, R １０４ , R １０５ may be bonded to each other to form a ring. １０４ , R １０５ is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. The number of carbon atoms in the chain alkyl group is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 3.１０４ , R １０５ The number of carbon atoms in the chain alkyl group of R is preferably as small as possible within the above range of carbon atoms, for reasons such as good solubility in resist solvents. １０４ , R １０５ In the chain alkyl group, the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength and the improved transparency to high-energy light of 250 nm or less and electron beams, which is preferable. The proportion of fluorine atoms in the chain alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms. In formula (b-2), V １０２ , V １０３ are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and each represents V in formula (b-1). １０１ In formula (b-2), L １０１ , L １０２ are each independently a single bond or an oxygen atom.

[0380] Anion in component (b-3) In formula (b-3), R １０６ ~R １０８ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R １０１ In formula (b-3), L １０３ ~L １０５ each independently represents a single bond, —CO— or —SO ２ - is.

[0381] Of the above, the anion moiety of component (B) is preferably the anion in component (b-1), and more preferably the anion represented by formula (an-1).

[0382] {Cation Moiety} In the formula (b-1), formula (b-2), and formula (b-3), M' ｍ＋represents an m-valent onium cation. Among these, sulfonium cation and iodonium cation are preferred. m is an integer of 1 or more.

[0383] The cation moiety of the component (B) is preferably a sulfonium cation, more preferably a cation represented by each of the formulas (ca-1) to (ca-3), still more preferably a cation represented by the formula (ca-1), and particularly preferably a cation represented by each of the formulas (ca-1-1) to (ca-1-84).

[0384] In the resist composition of this embodiment, the component (B) may be used singly, or two or more types may be used in combination. When the resist composition contains the component (B), the amount of the component (B) in the resist composition, relative to 100 parts by mass of the component (A), is preferably less than 50 parts by mass, more preferably 5 to 45 parts by mass, and even more preferably 10 to 43 parts by mass. By ensuring that the amount of the component (B) falls within the above-mentioned preferred range, a homogeneous solution is more likely to be obtained when the respective components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition is favorable.

[0385] <<Base Component (D)>> In addition to the component (A), the resist composition of this embodiment may contain a base component (component (D)) that traps acid generated upon exposure (i.e., controls the diffusion of acid). The component (D) acts as a quencher (acid diffusion controller) that traps acid generated in the resist composition upon exposure. Examples of the component (D) include a photodegradable base (D1) (hereinafter referred to as “component (D1)”) that decomposes upon exposure and loses its ability to control acid diffusion, and a nitrogen-containing organic compound (D2) (hereinafter referred to as “component (D2)”) that does not fall under the category of component (D1). Among these, the photodegradable base (component (D1)) is preferred because it is likely to enhance all of the properties of high sensitivity, reduced roughness, and suppressed coating defects. The components (D1) and (D2) may be contained in the form of a compound, or may be incorporated into the component (A1) as the aforementioned structural unit (a6), or may take both of these forms. The compounds exemplified below as the component (D1) may be used as the acid generator component (component (B)) in some cases in combination with other compounds.

[0386] Regarding the component (D1): The component (D1) is not particularly limited as long as it decomposes upon exposure and loses its acid diffusion controllability, and is preferably one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)"). The components (d1-1) to (d1-3) decompose and lose their acid diffusion controllability (basicity) in the exposed areas of the resist film, and therefore do not act as quenchers, but act as quenchers in the unexposed areas of the resist film.

[0387] [In the formula, Rd １ ~Rd ４ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２In the above, no fluorine atom is bonded to the carbon atom adjacent to the S atom. １ is a single bond or a divalent linking group; m is an integer of 1 or more; M ｍ＋ are each independently an m-valent organic cation.

[0388] {Component (d1-1)} Anion portion In formula (d1-1), Rd １ represents Rd in the general formula (d1-an-1) １ Preferred examples of the anion moiety of the component (d1-1) include those given as preferred specific examples of the anion represented by the general formula (d1-an-1) above.

[0389] ...cation moiety In formula (d1-1), M ｍ＋ is an m-valent organic cation. ｍ＋ Suitable examples of the organic cation include the same as the cations represented by the general formulae (ca-1) to (ca-3), with the cation represented by the general formula (ca-1) being more preferred, and the cations represented by the general formulae (ca-1-1) to (ca-1-84) being even more preferred. One type of component (d1-1) may be used alone, or two or more types may be used in combination.

[0390] {Component (d1-2)} Anion portion In formula (d1-2), Rd ２ represents Rd in the general formula (d1-an-2) ２ Preferred examples of the anion moiety of the component (d1-2) include those given as preferred specific examples of the anion represented by the above general formula (d1-an-2).

[0391] In formula (d1-2), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋ The component (d1-2) may be used alone or in combination of two or more.

[0392] {Component (d1-3)} Anion portion In formula (d1-3), Rd ３is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, a fluorinated alkyl group is preferred, and the Rd １ The same fluorinated alkyl groups as those mentioned above are more preferred.

[0393] In formula (d1-3), Rd ４ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, an alkyl group, an alkoxy group, an alkenyl group, or a cyclic group, which may have a substituent, is preferable. ４ The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. ４ A part of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, etc. ４ The alkoxy group in is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

[0394] Rd ４ The alkenyl group in R' ２０１ Examples include the same alkenyl groups as those in the above, and vinyl, propenyl (allyl), 1-methylpropenyl, and 2-methylpropenyl groups are preferred. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

[0395] Rd ４ The cyclic group in ２０１Examples thereof include cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclo[5.2.1.0], and the like. ２，６ ] An alicyclic group in which one or more hydrogen atoms have been removed from a cycloalkane such as decane or tetracyclododecane, or an aromatic group such as a phenyl group or naphthyl group is preferred. ４ When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, resulting in excellent lithography properties. ４ When is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition exhibits excellent light absorption efficiency, and exhibits favorable sensitivity and lithography properties.

[0396] In formula (d1-3), Yd １ represents a single bond or a divalent linking group. １ The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. ２１ Examples of the divalent linking group include the same divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom as those mentioned in the description of the divalent linking group in １ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0397] Specific examples of preferred anion moieties of component (d1-3) are shown below.

[0398]

[0399]

[0400] In formula (d1-3), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋The component (d1-3) may be used alone or in combination of two or more.

[0401] The component (D1) may be any one of the above components (d1-1) to (d1-3), or a combination of two or more of them. When the resist composition contains the component (D1), the amount of the component (D1) within the resist composition is preferably 0.5 to 15 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 15 parts by mass, relative to 100 parts by mass of the component (A).

[0402] The component (D1) preferably contains the component (d1-1). The content of the component (d1-1) in the entire component (D1) is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more. The component (D1) may consist solely of the compound component (d1-1).

[0403] Production Method of Component (D1): The production methods of the components (d1-1) and (d1-2) described above are not particularly limited, and they can be produced by known methods. Furthermore, the production method of the component (d1-3) is also not particularly limited, and for example, it can be produced in a manner similar to the method described in US 2012-0149916 . The compound of component (D1) has been shown as an example of a base component (component (D)) that traps acid generated upon exposure, but the compound of component (D1) may also be used as component (B). For example, in the resist composition of this embodiment, the compound of component (D1) may be used as component (B), and a compound that generates an acid with a lower acidity than the acid generated by the compound of component (D1) upon exposure may be used as component (D). Furthermore, in the resist composition of this embodiment, the compound of component (D1) may be used as component (B), and the component (D2), described below, may be used as component (D).

[0404] Regarding the (D2) component: The (D) component may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the above-mentioned (D1) component. The (D2) component is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of the (D1) component, and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are more preferred. The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms. Examples of the aliphatic amine include ammonia NH ３ Examples of the amine include amines in which at least one hydrogen atom is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 6 to 30 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0405] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of aliphatic monocyclic amines include piperidine and piperazine. Specific examples of aliphatic polycyclic amines include those having 6 to 10 carbon atoms, such as 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0406] 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.

[0407] Furthermore, the component (D2) may be an aromatic amine, such as 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole, or a derivative thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, or 2,6-di-tert-butylpyridine.

[0408] The component (D2) may be used singly, or in combination of two or more types. When the resist composition contains the component (D2), the amount of the component (D2) within the resist composition is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A). By ensuring that the amount is within this range, the resist pattern shape and stability over time during storage can be improved.

[0409] <<At least one compound (E) selected from the group consisting of organic carboxylic acids, and phosphorus oxo acids and their derivatives>> The resist composition of this embodiment may contain at least one compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, and phosphorus oxo acids and their derivatives as an optional component for the purposes of preventing sensitivity degradation and improving resist pattern shape and post-exposure stability. Specific examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid, with salicylic acid being preferred. Examples of phosphorus oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred.

[0410] In the resist composition of this embodiment, the component (E) may be used singly, or two or more different components may be used in combination. When the resist composition contains the component (E), the amount of the component (E) per 100 parts by mass of the component (A) is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass. By ensuring that the amount is within this range, lithography properties are further improved.

[0411] <Fluorine Additive Component (F)> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as "component (F)") as a hydrophobic resin. The component (F) is used to impart water repellency to the resist film, and by using it as a resin separate from component (A), it is possible to improve lithography properties. Examples of component (F) that can be used include the fluorine-containing polymer compounds described in JP 2010-002870 A, JP 2010-032994 A, JP 2010-277043 A, JP 2011-13569 A, and JP 2011-128226 A. More specific examples of component (F) include polymers having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting only of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1), and more preferably a copolymer of the structural unit (f1) with the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate, and more preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate.

[0412] [wherein R is the same as defined above, and Rf １０２ and Rf １０３ Rf each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; １０２ and Rf １０３ may be the same or different. １ is an integer of 0 to 5, and Rf １０１ is an organic group containing a fluorine atom.

[0413] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. １０２ and Rf １０３ The halogen atom in Rf is preferably a fluorine atom. １０２ and Rf １０３ Examples of the alkyl group having 1 to 5 carbon atoms in Rf include the same alkyl groups having 1 to 5 carbon atoms as those in R, and a methyl group or an ethyl group is preferred. １０２ and Rf １０３ Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is preferred. Among these, Rf １０２ and Rf １０３ In formula (f1-1), nf is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group, and still more preferably a hydrogen atom. １ is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0414] In formula (f1-1), Rf １０１ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The hydrocarbon group containing a fluorine atom may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. In addition, the hydrocarbon group containing a fluorine atom is preferably one in which 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among these, Rf １０１ is preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, more preferably a trifluoromethyl group, —CH ２ -CF ３ , -CH ２ -CF２ -CF ３ , -CH(CF ３ ) ２ , -CH ２ -CH ２ -CF ３ , -CH ２ -CH ２ -CF ２ -CF ２ -CF ２ -CF ３ is particularly preferred.

[0415] The weight-average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. When the Mw is below the upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, while when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

[0416] In the resist composition of this embodiment, the component (F) may be used either as a single type, or as a combination of two or more types. When the resist composition contains the component (F), the amount of the component (F) relative to 100 parts by mass of the component (A) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass.

[0417] <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)"). In the resist composition of this embodiment, the component (S) may be used alone, or as a mixed solvent of two or more different solvents. Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), γ-butyrolactone, ethyl lactate (EL), and cyclohexanone are preferred.

[0418] Also preferred as the (S) component is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into consideration the compatibility of PGMEA with the polar solvent, etc. Also preferred as the (S) component is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone. In this case, the mass ratio of the former to the latter is preferably 70:30 to 95:5. The amount of the (S) component is not particularly limited and is appropriately set according to the coating film thickness at a concentration that allows application to a substrate, etc. The (S) component is generally used so that the solids concentration of the resist composition is within the range of 0.1 to 20 mass%, preferably 0.2 to 15 mass%.

[0419] The resist composition of this embodiment may be prepared by dissolving the resist material in component (S) and then removing impurities 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.

[0420] The resist composition of this embodiment as described above achieves high sensitivity in resist pattern formation, and also improves both the effect of reducing roughness and the exposure latitude. In addition, the resist composition of this embodiment has good storage stability, and its lithography properties are unlikely to change over time during storage. The polymer contained in the resist composition of this embodiment has a group represented by general formula (I-1) (terminal group (I-1)) at at least one end of the main chain. This terminal group (I-1) is a specific group (R ２). That is, a polymer having such an end group (I-1) also has an iodine atom introduced into at least one end of the main chain of the polymer. By using this polymer as a resin component for a chemically amplified resist composition, the light absorption of the resist film is improved. Furthermore, the rigidity of the resist film is increased, and the acid diffusion suppression effect is likely to be enhanced. In addition, because a functional group having an iodine atom (ionic group (i), ionic group (ii), hydrocarbon group (iii)) is directly bonded to the linking group (X) directly attached to the main chain, the dissolution contrast between exposed and unexposed areas of the resist film in a developer is increased. Furthermore, because the divalent linking group (X) does not contain a sulfide bond (-S-), the resist composition is less likely to change over time. Therefore, it is presumed that the effects of the resist composition of this embodiment are achieved by the above-mentioned synergistic effect.

[0421] (Method of Forming a Resist Pattern) One embodiment of the method of forming a resist pattern 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. An example of one embodiment of the method of forming a resist pattern is a method of forming a resist pattern carried out as follows.

[0422] First, the resist composition of the above-described embodiment is applied to a support using a spinner or the like, and baked (post-applied bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an ArF lithography device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without a mask pattern. The resist film is then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed. In the case of an alkali development process, the development is performed using an alkaline developer, and in the case of a solvent development process, a developer containing an organic solvent (organic developer) is used.

[0423] After the development treatment, a rinse treatment is preferably carried out. In the case of an alkaline development process, the rinse treatment is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse solution containing an organic solvent is preferably used. In the case of a solvent development process, after the development treatment or rinse treatment, a treatment may be carried out to remove the developer or rinse solution adhering to the pattern using a supercritical fluid. After the development treatment or rinse treatment, drying is carried out. Furthermore, in some cases, a bake treatment (post-bake) may be carried out after the development treatment.

[0424] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those on which a predetermined wiring pattern is formed. More specifically, examples include silicon wafers, substrates made of metals such as copper, chromium, iron, and aluminum, and glass substrates. Materials that can be used for the wiring pattern include copper, aluminum, nickel, and gold.

[0425] The wavelength used for exposure is not particularly limited, and may be an ArF excimer laser, a KrF excimer laser, or a F ２Radiation such as excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. The method of forming a resist pattern of this embodiment is particularly useful for a method in which the resist film is exposed to EUV (extreme ultraviolet) or EB (electron beam) in the step of exposing the resist film.

[0426] The exposure method for the resist film may be a normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be liquid immersion exposure (liquid immersion lithography). Liquid immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure apparatus is filled in advance with a solvent (immersion medium) having a refractive index greater than that of air, and exposure (immersion exposure) is performed in this state. The liquid immersion medium is preferably a solvent having a refractive index greater than that of air and smaller than that of the resist film to be exposed, and examples thereof include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent. Water is preferably used as the liquid immersion medium.

[0427] An example of an alkaline developer used in the development treatment in the alkaline development process is a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent that can dissolve component (A) (component (A) before exposure), and can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents.

[0428] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

[0429] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0430] The organic developer may contain known additives as needed. Examples of such additives include surfactants. The surfactants are not particularly limited, but may include, for example, ionic or nonionic fluorine-based and / or silicon-based surfactants.

[0431] The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the surface of the support by surface tension and leaving it standing for a certain period of time (puddle method), a method of spraying the developer onto the surface of the support (spray method), or a method of continuously applying the developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0432] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be appropriately selected from the organic solvents listed above as organic solvents used in the organic developer, as long as they do not easily dissolve the resist pattern. Typically, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. These organic solvents may be used alone or in combination with two or more. They may also be used in combination with other organic solvents or water.

[0433] The rinse treatment (cleaning treatment) using a rinse solution can be carried out by a known rinse method, such as a method of continuously applying the rinse solution onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse solution for a certain period of time (dipping method), or a method of spraying the rinse solution onto the surface of the support (spray method).

[0434] According to the method of forming a resist pattern of the present embodiment as described above, the resist composition described above is used, thereby achieving high sensitivity in the formation of the resist pattern, increasing the exposure latitude, and enabling the formation of a resist pattern with a good shape and reduced roughness.

[0435] The resist composition of the above-described embodiment and the various materials used in the pattern formation method of the above-described embodiment (e.g., resist solvent, developer, rinse, anti-reflective coating composition, top coat composition, etc.) preferably do not contain impurities such as metals, halogen-containing metal salts, acids, alkalis, or components containing sulfur or phosphorus atoms. Examples of impurities containing metal atoms include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, or salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially free of impurities (below the detection limit of the measuring device).

[0436] (Compound) One embodiment of the compound is a compound represented by the following general formula (I).

[0437] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. The plurality of R present in the formula １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different. N is a nitrogen atom.

[0438] In the formula (I), R １ , Z, X, R ２ represents R in the above formula (I-1). １ , Z, X, R ２ In addition, the plurality of R １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different from each other, but are preferably the same from an industrial viewpoint. The compound of this embodiment, i.e., the compound represented by the above general formula (I), is the same as the above-mentioned compound (I).

[0439] [Method for Producing Compound] One embodiment of the method for producing a compound represented by general formula (I) (compound (I)) is a production method comprising a step of reacting a compound represented by the following general formula (I-01) (hereinafter also referred to as "compound (I-01)") with a compound represented by the following general formula (I-02) (hereinafter also referred to as "compound (I-02)").

[0440] [In formula (I-01), R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X' is a divalent linking group (excluding those containing a sulfide bond (-S-)). In formula (I-02), R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent.

[0441] In the formula (I-01), R １ , Z is R in the formula (I-1) １ , and Z. In addition, the plurality of R １ , a plurality of Z's, and a plurality of X's may be the same or different from one another, but are preferably the same from an industrial viewpoint. ２ represents R in formula (I-1). ２ In formula (I-01), examples of the divalent linking group for X′ include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom, and examples thereof include the same divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom as exemplified in the description of X in formula (I-1) above.

[0442] The method for producing the compound according to this embodiment is not particularly limited as long as it includes a step of reacting compound (I-01) with compound (I-02). For example, compound (I) can be produced by subjecting compound (I-01) and compound (I-02) to a condensation reaction using a known synthesis method.

[0443] Another embodiment of the method for producing compound (I) is a production method comprising a step of reacting a compound represented by the following general formula (I-03) (hereinafter also referred to as "compound (I-03)") with thionyl chloride to obtain a compound (hereinafter also referred to as "compound (I-05)"), with a compound represented by the following general formula (I-04) (hereinafter also referred to as "compound (I-04)") or compound (I-02).

[0444] [In formula (I-03) and formula (I-05), R １ , Z is R in the formula (I-01) １ , and Z, respectively. X″ is a divalent linking group (excluding those containing a sulfide bond (—S—)), and is the same as X′ in the formula (I-01). In addition, the plurality of R １ , a plurality of Z's, and a plurality of X's may be the same or different from one another, but are preferably the same from an industrial viewpoint. ２ represents R in the formula (I-01). ２ is the same as above.]

[0445] In the method for producing a compound according to another embodiment, the reaction of compound (I-03) with thionyl chloride is the so-called chlorination of an alcohol, and compound (I-05) can be produced by reacting them using a known synthetic method. Then, depending on the purpose, compound (I-05) can be condensed with compound (I-04), which is a carboxylic acid, or compound (I-02), which is an alcohol, using a known synthetic method to produce compound (I).

[0446] Compound (I-01), compound (I-03), compound (I-02), and compound (I-04) may be commercially available or synthesized. After the reaction is completed, compound (I) in the reaction mixture may be isolated and purified. For the isolation and purification, a conventionally known method can be used, and for example, concentration, solvent extraction, distillation, crystallization, recrystallization, chromatography, or the like can be used alone or in combination of two or more of these. The structure of compound (I) obtained as described above is １ H-nuclear magnetic resonance (NMR) spectroscopy, １３ C-NMR spectroscopy, １９ This can be confirmed by common organic analysis methods such as F-NMR spectroscopy, infrared absorption (IR) spectroscopy, mass spectrometry (MS), elemental analysis, and X-ray crystal diffraction.

[0447] (Radical Polymerization Initiator) One embodiment of the radical polymerization initiator contains a compound (compound (I)) represented by the above-mentioned general formula (I). The radical polymerization initiator can be used as a polymerization initiator for polymerizing a monomer in a radical polymerization reaction for synthesizing a polymer. The radical polymerization initiator of this embodiment is a compound (compound (I)) having a specific group (R ２ ). By carrying out polymerization using such a radical polymerization initiator, an iodine atom is introduced into at least one terminal of the main chain of the polymer. By using this polymer in a chemically amplified resist composition, it is possible to achieve high sensitivity and improved lithography properties (roughness, exposure latitude, etc.). In this way, the radical polymerization initiator of this embodiment can be suitably used for the radical polymerization of polymers used in chemically amplified resist compositions.

[0448] The monomer to be radically polymerized using the radical polymerization initiator of this embodiment may be any monomer capable of radical polymerization, and is appropriately selected depending on the polymer to be produced. As the monomer to be polymerized using the radical polymerization initiator, an acrylic acid ester monomer, a vinyl monomer, or a styrene monomer is preferred, with an acrylic acid ester monomer being particularly preferred. Examples of the acrylic acid ester monomer include monomers that derive the aforementioned structural unit (a1), structural unit (a10), structural unit (a2), structural unit (a5), structural unit (a6), structural unit (a8), etc.

[0449] (Polymer) One embodiment of the polymer is a polymer having a group represented by the following general formula (I-1) (terminal group (I-1)) at at least one end of the main chain. The polymer of this embodiment has the terminal group (I-1), and thereby also has an iodine atom at at least one end of the main chain of the polymer. As a result, when the polymer of this embodiment is used in a resist composition, high sensitivity and improved lithography properties (roughness, exposure latitude, etc.) can be achieved in resist pattern formation.

[0450] [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.]

[0451] In the formula (I-1), R １ , Z, X, R ２ represents R in the above-mentioned formula (I-1). １ , Z, X, R ２ and the same respectively.

[0452] The polymer of this embodiment may have an end group (I-1) at at least one end of the main chain, and known structural units may be used for other components (for example, structural units constituting the polymer) depending on the intended use of the polymer. The polymer of this embodiment is useful for resist compositions. The polymer of this embodiment is particularly useful as a base component for chemically amplified resist compositions, or as an additive component that is optionally blended into such resist compositions. Of these, it is particularly preferable for the polymer to be used as a base component for chemically amplified resist compositions. The structure of the polymer used as the base component is the same as that of the component (A1-0) described above.

[0453] The polymer of this embodiment is preferably a radical polymer obtained by radical polymerization using a radical polymerization initiator containing the compound represented by the general formula (I) described above.

[0454] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In these examples, the compound represented by chemical formula (1) will be referred to as "compound (1)," and the same applies to compounds represented by other chemical formulas.

[0455] <Production of Compounds> [Synthesis of Compound (I-iii-11)] 4,4'-Azobis(4-cyanovaleric acid) (12.6 g, 45.0 mmol), 4-iodophenol (19.8 g, 9.0 mmol), and dimethylaminopyridine (DMAP) (0.6 g, 4.8 mmol) were dissolved in 200 g of dichloromethane, and diisopropylcarbodiimide (DIC) (12.5 g, 100 mmol) was added to the solution. After stirring at room temperature for 16 hours, insoluble matter was removed by filtration. After distilling off the solvent, crystallization was carried out using acetone and heptane to obtain Compound (I-iii-11) (25.2 g, yield=82.0%).

[0456]

[0457] [Synthesis of Compounds (I-iii-12) and (I-iii-13)] Compounds (I-iii-12) and (I-iii-13) were obtained in the same manner as in the synthesis of compound (I-iii-11), except that in the synthesis of compound (I-iii-11) described above, 4-iodophenol was changed to the following phenols (PO-2, PO-3) in equimolar amounts, respectively.

[0458]

[0459] [Synthesis of Compound (I-iii-14)] 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (14.4 g, 50.0 mmol) was dissolved in 100 g of dichloromethane, and then thionyl chloride (7.1 g, 60.0 mmol) was added dropwise at 10°C or lower. After stirring at room temperature for 3 hours, the mixture was diluted with 1% NH ３ The residue was washed three times with 100 g of aqueous solution and four times with 100 g of ultrapure water. After the solvent was distilled off, the residue was dried under reduced pressure to obtain a precursor (Pre-01) (13.0 g, yield=80.0%).

[0460]

[0461] 4-Iodobenzoic acid (12.4 g, 50.0 mmol) was dissolved in 50 g of dimethylformamide (DMF), and potassium carbonate (10.4 g, 75.0 mmol) was added to the solution. Subsequently, 50 g of a DMF solution of precursor (Pre-01) (14.6 g, 45.0 mmol) was added dropwise. After stirring at room temperature for 24 hours, 200 g of tert-butyl methyl ether (MTBE) and 40 g of methyl ethyl ketone (MEK) were added, and the mixture was washed three times with 200 g of ultrapure water. After distilling off the solvent, the mixture was crystallized using acetone, tetrahydrofuran (THF), and heptane to obtain compound (I-iii-14) (26.9 g, yield=80.0%).

[0462]

[0463] [Synthesis of Compounds (I-iii-15) and (I-iii-16)] Compounds (I-iii-15) and (I-iii-16) were obtained in the same manner as in the synthesis of compound (I-iii-14), except that 4-iodobenzoic acid in the synthesis of compound (I-iii-14) was changed to equimolar amounts of the following carboxylic acids (CA1 and CA2), respectively.

[0464]

[0465] [Synthesis of Compounds (I-i-11) to (I-i-13)] 1,1'-carbonyldiimidazole (CDI) (4.60 g, 28.4 mmol) and acetonitrile (20 g) were added to a 300 mL three-neck flask, and then a solution of 3-hydroxy-4-iodobenzoic acid (6.7 g, 25.5 mmol) dissolved in acetonitrile (20 g) was added dropwise over 30 minutes, and the mixture was allowed to react for 1 hour. Thereafter, compound (K-1) (9.5 g, 30.6 mmol) was added, and the mixture was allowed to react at 65°C for 3 hours. After cooling, ultrapure water (250 g) was added, and the mixture was stirred for 30 minutes, and the precipitated solid was filtered. The filtered product was again dissolved in methanol (100 g) and added dropwise to MTBE (500 g), and the precipitated solid was filtered. The filtered product was dried under reduced pressure to obtain intermediate 1 (7.3 g, yield = 70.1%).

[0466]

[0467] Intermediate 2 and Intermediate 3 were obtained in the same manner as in the synthesis of Intermediate 1, except that 3-hydroxy-4-iodobenzoic acid was changed to the following carboxylic acids (CA3 and CA4) in equimolar amounts, respectively.

[0468]

[0469] Intermediate 1 (5.6 g, 10.0 mmol) and Compound A (3.9 g, 11.5 mmol) for salt exchange were dissolved in dichloromethane (120 g), and ultrapure water (120 g) was added. The mixture was allowed to react at room temperature for 30 minutes. After the reaction was completed, the aqueous phase was removed, and the organic phase was washed four times with ultrapure water (120 g). The organic phase was concentrated to dryness using a rotary evaporator to obtain Intermediate 4 (6.3 g, yield = 95.0%).

[0470]

[0471] Intermediate 5 and Intermediate 6 were obtained in the same manner as in the synthesis of Intermediate 4, except that Intermediate 1 was changed to Intermediate 2 and Intermediate 3 in equimolar amounts, respectively.

[0472]

[0473] Compounds (I-i-11), (I-i-12), and (I-i-13) were obtained in the same manner as in the synthesis of compound (I-iii-11), except that 4-iodophenol was changed to equimolar amounts of intermediate 4, intermediate 5, and intermediate 6, respectively.

[0474]

[0475] [Synthesis of Compounds (I-i-14) to (I-i-16)] 5-Iodosalicylic acid (5.3 g, 20.0 mmol) and Compound A (7.6 g, 22.2 mmol) were dissolved in dichloromethane (200 g), and 50 g of a 2% aqueous sodium hydroxide solution was added, followed by reaction at room temperature for 30 minutes. After completion of the reaction, the aqueous phase was removed, and the organic phase was washed five times with ultrapure water (50 g). The organic phase was concentrated to dryness using a rotary evaporator to obtain Intermediate 7 (9.7 g, yield=92.0%).

[0476]

[0477] Intermediate 8 and Intermediate 9 were obtained in the same manner as in the synthesis of Intermediate 7, except that 5-iodosalicylic acid was replaced with the above-mentioned carboxylic acids (CA3 and CA4) in equimolar amounts, respectively.

[0478]

[0479] Compounds (I-i-14), (I-i-15), and (I-i-16) were obtained in the same manner as in the synthesis of compound (I-iii-14), except that 4-iodobenzoic acid was changed to equimolar amounts of intermediates 7, 8, and 9, respectively.

[0480]

[0481] [Synthesis of Compounds (I-ii-11) to (I-ii-13)] Diphenyl sulfoxide (20.2 g, 100 mmol), 2-iodophenol (22.0 g, 100 mmol), and trifluoromethanesulfonic anhydride (31.0 g, 110 mmol) were stirred in 300 g of dichloromethane at −20° C. for 2 hours. 400 g of aqueous sodium bicarbonate solution was added thereto, and the mixture was stirred at room temperature. The organic layer was then recovered and the solvent was distilled off. The resulting residue was purified by silica gel column chromatography to obtain Compound (B-1-a) (33.2 g, yield 60.0%). A methanol solution of 28 g of Compound (B-1-a) was subjected to anion exchange with a strong basic ion exchange resin to obtain a solution of Compound (Compound B). The solvent was distilled off, and the residue was dried under reduced pressure to obtain Compound B (20.0 g, yield 90.0%).

[0482]

[0483] Compound C was obtained in the same manner as in the synthesis of Compound B described above, except that in the synthesis of Compound B, diphenyl sulfoxide was changed to bis(4-iodophenyl) sulfoxide and 2-iodophenol was changed to phenol in equimolar amounts. Furthermore, Compound D was obtained in the same manner as in the synthesis of Compound B described above, except that in the synthesis of Compound B, diphenyl sulfoxide was changed to bis(4-iodophenyl) sulfoxide in equimolar amounts.

[0484]

[0485] Compound (L-1) (4.1 g, 10.0 mmol) and compound B for salt exchange (4.7 g, 11.5 mmol) were dissolved in dichloromethane (120 g), and ultrapure water (120 g) was added. The mixture was allowed to react at room temperature for 30 minutes. After the reaction was completed, the aqueous phase was removed, and the organic phase was washed four times with ultrapure water (120 g). The organic phase was concentrated to dryness using a rotary evaporator to obtain intermediate 10 (6.1 g, yield=92.0%).

[0486]

[0487] Intermediate 11 and Intermediate 12 were obtained in the same manner as in the synthesis of Intermediate 10, except that Compound B was changed to the above-mentioned Compound C and Compound D in equimolar amounts, respectively.

[0488]

[0489] Compounds (I-ii-11), (I-ii-12), and (I-ii-13) were obtained in the same manner as in the synthesis of compound (I-iii-11), except that 4-iodophenol was changed to equimolar amounts of intermediates 10, 11, and 12, respectively.

[0490]

[0491] [Synthesis of Compounds (I-ii-14) to (I-ii-16)] 3,5-diiodosalicylic acid (3.9 g, 10.0 mmol) and Compound B (5.3 g, 12.0 mmol) were dissolved in dichloromethane (200 g), and 50 g of a 2% aqueous sodium hydroxide solution was added, followed by reaction at room temperature for 30 minutes. After completion of the reaction, the aqueous phase was removed, and the organic phase was washed five times with ultrapure water (50 g). After washing, the organic phase was concentrated to dryness using a rotary evaporator to obtain Intermediate 13 (7.5 g, yield=95.0%).

[0492]

[0493] Intermediate 14 and Intermediate 15 were obtained in the same manner as in the synthesis of Intermediate 13, except that Compound B was changed to the above-mentioned Compound C and Compound D in equimolar amounts, respectively.

[0494]

[0495] Compounds (I-ii-14), (I-ii-15), and (I-ii-16) were obtained in the same manner as in the synthesis of compound (I-iii-11), except that 4-iodophenol was changed to equimolar amounts of intermediates 13, 14, and 15, respectively.

[0496]

[0497] Obtain られた compound (I-iii-11) ~ compound (I-iii-16), compound (I-i-11) ~ compound (I-i-16), compound Object (I-ii-11) ~ Compound (I-ii-16) were determined by NMR measurement. The analysis results are shown below and the structure and structure are determined.

[0498] Compound (I-iii-11): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 7.73-7.77 (dd, I-ArH, 4H), 6.73-6.77 (dd, I-ArH, 4H), 2.22-2.38 (m, CH2CH2, 8H), 1.62-1.66 (d, CH3, 6H)

[0499] Compound (I-iii-12): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.05 (d, I-ArH, 2H), 7.73-7.77 (dd, I-ArH, 2H), 6.73-6.77 (dd, I-ArH, 2H), 2.22-2.38 (m, CH2CH2, 8H), 1.62-1.66 (d, CH3, 6H)

[0500] Compound (I-iii-13): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 8.05 (d, I-ArH, 2H), 2.22-2.38 (m, CH2CH2, 8H), 1.62-1.66 (d, CH3, 6H)

[0501] Compound (I-iii-14): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 7.73-7.77 (dd, I-ArH, 4H), 7.45 (t, NH, 2H), 6.73-6.77 (dd, I-ArH, 4H), 3.43 (t, CH2, 4H), 3.23-3.25(m, CH2, 4H), 1.25(s, CH3, 12H)

[0502] Compound (I-iii-15): １H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.05 (d, I-ArH, 2H), 7.73-7.77 (dd, I-ArH, 2H), 7.45 (t, NH, 2H), 6.73-6.77 (dd, I-ArH, 2H), 3.43 (t, CH2, 4H), 3.23-3.25 (m, CH2, 4H), 1.25 (s, CH3, 12H)

[0503] Compound (I-iii-16): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 8.05 (d, I-ArH, 2H), 7.45 (t, NH, 2H), 3.43 (t, CH2, 4H), 3.23-3.25 (m, CCH2, 4H), 1.25(s, CCH3, 12H)

[0504] Compound (I-i-11): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 7.73-7.90 (dd, ArH+I-ArH, 32H), 6.94(d, I-ArH, 2H), 6.73-6.77(dd, I-ArH, 2H), 4.51-4.68 (m, CH2, 4H), 2.22-2.38 (m, CH2CH2, 8H), 1.62-1.66 (d, CH3, 6H)

[0505] Compound (I-i-12): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.05 (d, I-ArH, 2H), 7.74-7.90 (m, ArH+I-ArH, 32H), 4.51-4.68 (m, CH2, 4H), 2.22-2.38 (m, CH2CH2, 8H), 1.62-1.66 (d, CH3, 6H)

[0506] Compound (I-i-13): １H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 7.74-7.90 (m, ArH, 30H), 4.51-4.68 (m, CH2, 4H), 2.22-2.38 (m, CCH2CH2, 8H), 1.62-1.66(d, CH3, 6H)

[0507] Compound (I-i-14): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 7.74-7.90 (m, ArH+I-ArH, 34), 7.45 (t, NH, 2H), 6.73-6.77 (dd, I-ArH, 2H), 3.43 (t, CH2, 4H), 3.23-3.25(m, CH2, 4H), 1.25(s, CH3, 12H)

[0508] Compound (I-i-15): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.05 (d, I-ArH, 2H), 7.74-7.90 (m, ArH+I-ArH, 32), 7.45 (t, NH, 2H), 3.43 (t, CH2, 4H), 3.23-3.25(m, CH2, 4H), 1.25(s, CH3, 12H)

[0509] Compound (I-i-16): １ H-NMR (DMSO-d6, 400MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 7.74-7.90 (m, ArH, 30), 7.45 (t, NH, 2H), 3.43 (t, CH2, 4H), 3.23-3.25 (m, CH2, 4H), 1.25 (s, CH3, 12H)

[0510] Compound (I-ii-11): １H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 7.74 - 7.90 (m, ArH, 20H), 7.56 - 7.60 (dd, I-ArH, 2H), 7.42 - 7.50 (m, ArH, 10H), 7.12 - 7.16 (dd, I-ArH, 2H), 4.51 - 4.68 (m, CH2, 4H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H)

[0511] Compound (I-ii-12): １ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 8.16 - 8.20 (dd, I-ArH, 8H), 7.77 - 7.81 (dd, ArH, 4H), 7.42 - 7.50 (m, ArH+I-ArH, 18H), 7.12 - 7.16 (dd, I-ArH, 4H), 4.51 - 4.68 (m, CH2, 4H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H)

[0512] Compound (I-ii-13): １ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 8.32 (d, I-ArH, 2H), 8.16 - 8.20 (dd, I-ArH, 8H), 7.56 - 7.60 (dd, I-ArH, 2H), 7.42 - 7.50 (m, ArH+I-ArH, 18H), 7.12 - 7.16 (dd, I-ArH, 2H), 4.51 - 4.68 (m, CH2, 4H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H)

[0513] Compound (I-ii-14): １H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 10.8 (s, OH, 2H), 8.32 (d, I-ArH, 4H), 8.03 (d, I-ArH, 2H), 7.74 - 7.90 (m, ArH, 20H), 7.56 - 7.60 (dd, I-ArH, 2H), 7.12 - 7.16 (dd, I-ArH, 2H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H) [

[0514] [ Compound (I-ii-15): １ [ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 10.8 (s, OH, 2H), 8.32 (d, I-ArH, 2H), 8.16 (d, I-ArH, 8H), 8.03 (d, I-ArH, 2H), 7.77 - 7.81 (dd, ArH, 4H), 7.46 - 7.50 (dd, I-ArH, 8H), 7.12 - 7.16 (dd, ArH, 4H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H) [

[0515] [ Compound (I-ii-16): １ [ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 10.8 (s, OH, 2H), 8.32 (d, I-ArH, 4H), 8.16 (d, I-ArH, 8H), 8.03 (d, I-ArH, 2H), 7.56 - 7.60 (dd, I-ArH, 2H), 7.46 - 7.50 (dd, I-ArH, 8H), 7.12 - 7.16 (dd, ArH, 2H), 2.22 - 2.38 (m, CH2CH2, 8H), 1.62 - 1.66 (d, CH3, 6H) [

[0516] [[Synthesis of Compound (a5-2m)] 3,5-diiodosalicylic acid (40.0 g) and THF (160.0 g) were charged and dissolved with stirring. 1,1'-carbonyldiimidazole (CDI) (20.0 g) was added thereto, and the mixture was heated to 60°C in a water bath and stirred for 1 hour. Compound (K-2) (46.6 g) was added thereto and aged for 1 hour. Then, ultrapure water (160.0 g) and dichloromethane (160.0 g) were charged thereto and stirred. After stirring was stopped, the aqueous layer was removed, and the organic layer was further washed with ultrapure water (160 g). The organic layer was concentrated under reduced pressure, and the concentrated residue was crystallized from acetonitrile / tert-butyl methyl ether to obtain 43.2 g of a white compound (intermediate A).

[0517]

[0518] 4-Vinylbenzoic acid (9.6 g), Intermediate A (40.0 g), 4-dimethylaminopyridine (0.7 g), and dichloromethane (400.0 g) were mixed and stirred at 0°C, and 1,3-diisopropylcarbodiimide (8.9 g) was added thereto. After stirring at room temperature for 3 hours, the mixture was concentrated under reduced pressure. The concentrated residue was crystallized from acetonitrile / tert-butyl methyl ether to obtain 32.0 g of a white compound (Intermediate B).

[0519]

[0520] Intermediate B (30.0 g), compound E (25.0 g), dichloromethane (150.0 g), and ultrapure water (60.0 g) were mixed, stirred at room temperature, and the mixture was separated. The organic layer was washed five times with ultrapure water (60.0 g) and then concentrated under reduced pressure to obtain 30.5 g of compound (a5-2m).

[0521]

[0522] The resulting compound (a5-2m) was subjected to NMR measurement, and its structure was identified from the analytical results shown below. １H-NMR (DMSO-d6,400MHz): δ (ppm) = 8.31 (d, 1H), 8.13 (d, 1H), 7.72-8.00 (m, 17H ), 7.60-7.64 (m, 2H), 6.85-6.92 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 5.25 (m, 1H).

[0523] <Production of Copolymer> [Synthesis of Copolymer (A1-001)] 10.0 g of compound (a10-1pre), 8.8 g of compound (a1-1m), and 4.9 g of compound (I-iii-11) as a polymerization initiator were dissolved in 100 g of methyl ethyl ketone (MEK), heated to 70 ° C under a nitrogen atmosphere, and stirred for 5 hours. Thereafter, 3.2 g of acetic acid and 60 g of methanol (MeOH) were added to the reaction solution, and a deprotection reaction was carried out at 30 ° C for 18 hours. After completion of the reaction, 1200 g of a mixed solvent of methanol and water was added to the resulting reaction solution to cause precipitation and washing. The resulting white solid was filtered and dried under reduced pressure overnight to obtain the target copolymer (A1-001) (12.5 g, yield 66.4%).

[0524]

[0525] [Synthesis of Copolymers (A1-002) to (A1-030)] Copolymers (A1-002) to (A1-030) were obtained in the same manner as in the synthesis of copolymer (A1-001), except that the monomers that derive the structural units constituting each copolymer were blended in a predetermined molar ratio and a predetermined radical polymerization initiator was used. The monomers used in the production of the copolymers are shown below.

[0526]

[0527]

[0528] The resulting copolymers (A1-001) to (A1-030) are shown below. In the following chemical formulas, l, m, n, and o represent the composition ratio (molar ratio) of each structural unit. [ ] in the formulas indicates the terminal structure of the polymer main chain.

[0529]

[0530]

[0531]

[0532]

[0533]

[0534]

[0535]

[0536]

[0537]

[0538] [Synthesis of Copolymer (A2-1), Copolymer (A2-4), and Copolymer (A2-5)] Copolymer (A2-1), copolymer (A2-4), and copolymer (A2-5) were obtained in the same manner as in the synthesis of copolymer (A1-001), except that monomers from which the structural units constituting each copolymer are derived were blended in a predetermined molar ratio and a predetermined radical polymerization initiator was used.

[0539] [Synthesis of Copolymer (A2-2)] 13.2 g of compound (a10-1pre), 11.6 g of compound (a1-1m), 2.2 g of azobis(isobutyrate) dimethyl (V-601) as a polymerization initiator, and 3.0 g of chain transfer agent (v-1) were dissolved in 130 g of methyl ethyl ketone (MEK), heated to 70 ° C. under a nitrogen atmosphere, and stirred for 5 hours. Thereafter, 4.2 g of acetic acid and 80 g of methanol (MeOH) were added to the reaction solution, and a deprotection reaction was carried out at 30 ° C. for 18 hours. After completion of the reaction, heptane (600 g) was added to the resulting reaction solution to precipitate and wash. The resulting white solid was filtered and dried under reduced pressure overnight to obtain the target copolymer (A2-2).

[0540]

[0541] [Synthesis of Copolymer (A2-3)] Copolymer (A2-3) was obtained in the same manner as in the synthesis of copolymer (A2-2), except that monomers from which structural units constituting the copolymer were derived were blended in a predetermined molar ratio, azobis(isobutyrate) dimethyl (V-601) was used as the polymerization initiator, and a predetermined chain transfer agent (v-2) was used.

[0542]

[0543] The radical polymerization initiators and chain transfer agents used in the production of the copolymers (A2-1) to (A2-5) are shown below.

[0544]

[0545] The resulting copolymers (A2-1) to (A2-5) are shown below. In the chemical formulas below, l, m, n, and o represent the composition ratio (molar ratio) of each structural unit. [ ] in the formulas indicates the terminal structure of the polymer main chain.

[0546]

[0547] The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) of each copolymer were determined by GPC measurement (standard polystyrene equivalent). The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) of each copolymer was determined by carbon-13 nuclear magnetic resonance spectroscopy (150 MHz, １３ These results are shown in Tables 1 to 3 together with the radical polymerization initiators or chain transfer agents used.

[0548]

[0549]

[0550]

[0551] <Preparation of Resist Compositions> (Examples 1 to 35, Comparative Examples 1 to 5) The components shown in Tables 4 to 6 were mixed and dissolved to prepare the resist compositions of each example.

[0552]

[0553]

[0554]

[0555] In Tables 4 to 6, the abbreviations have the following meanings. The numbers in brackets [ ] indicate the blend amount (parts by mass). (A)-1 to (A)-30: the above copolymers (A1-001) to (A1-030). (A)-31 to (A)-35: the above copolymers (A2-1) to (A2-5).

[0556] (B)-1: An acid generator comprising a compound represented by the following chemical formula (B1-1): (B)-2: An acid generator comprising a compound represented by the following chemical formula (B1-2):

[0557]

[0558] (D)-1: An acid diffusion controller comprising a compound represented by the following chemical formula (D1-1): (D)-2: An acid diffusion controller comprising a compound represented by the following chemical formula (D1-2):

[0559]

[0560] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0561] <Formation of Resist Pattern> Step of Forming Resist Film: Each resist composition of the examples was applied using a spinner onto an 8-inch silicon substrate that had been treated with hexamethyldisilazane (HMDS), and the applied resist composition was pre-baked (PAB) on a hot plate at a temperature of 110°C for 60 seconds, followed by drying to form a resist film with a thickness of 50 nm.

[0562] Step of exposing resist film: Next, the resist film was subjected to exposure to light using an electron beam lithography system JEOL-JBX-9300FS (manufactured by JEOL Ltd.) at an acceleration voltage of 100 kV, with a target size of a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a line width of 25 nm (pitch of 50 nm). Thereafter, post-exposure bake (PEB) treatment was performed at 100°C for 60 seconds.

[0563] Step of developing the exposed resist film: Next, alkaline development was carried out for 60 seconds at 23°C using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, a water rinse was carried out for 15 seconds using pure water. As a result, a 1:1 LS pattern with a line width of 25 nm (pitch of 50 nm) was formed.

[0564] [Evaluation of Optimal Exposure Dose (Eop)] The optimal exposure dose Eop (μC / cm) for forming an LS pattern of the target size by the above <Formation of Resist Pattern> was ２ This was called "Eop (μC / cm ２ ) are shown in Tables 7 to 9.

[0565] [Evaluation of LWR (Line Width Roughness)] For the LS patterns formed in the above <Formation of Resist Pattern>, 3σ, a measure of LWR, was determined. This is shown in Tables 7 to 9 as "LWR (nm)." The "3σ" indicates three times the standard deviation (σ) (unit: nm) obtained from the measurement results of 400 line positions measured in the longitudinal direction of the line using a scanning electron microscope (accelerating voltage 800 V, product name "S-9380", manufactured by Hitachi High-Technologies Corporation). The smaller the 3σ value, the smaller the roughness of the line sidewalls, meaning that an LS pattern with a more uniform width was obtained.

[0566] [Evaluation of 5% EL Margin] The exposure dose required to form an LS pattern of the target size by the above <Formation of Resist Pattern>, i.e., a 1:1 LS pattern with a line width of 25 nm (pitch of 50 nm), within a range of ±5% of the target dimensions, was determined, and the EL margin (unit: %) was calculated using the following formula. The results are shown in Tables 7 to 9 as "5% EL (%)."

[0567] EL margin (%) = (|E1 - E2 | / Eop) × 100 E1: exposure dose (μC / cm) when a line width pattern of 23.75 nm is formed ２ E2: exposure dose (μC / cm) when a line width pattern of 26.25 nm is formed ２The larger the EL margin, the smaller the amount of change in pattern size due to fluctuations in exposure dose, indicating a wider process margin.

[0568] [Evaluation of Storage Stability] Each of the prepared resist compositions was divided into a refrigerated storage sample at 5°C or below and a high-temperature storage sample at 60°C. After storing the storage samples at each temperature for 48 hours, patterning was performed according to the above <Formation of Resist Pattern>, and the optimal exposure dose Eop (μC / cm) at which an LS pattern of the target size was formed was evaluated for each storage sample. ２ The optimum exposure dose fluctuation rate was calculated by the following formula, and the storage stability was evaluated based on the following evaluation criteria. The results are shown in Tables 7 to 9.

[0569] Fluctuation rate of optimal exposure (%) = (optimum exposure of sample stored at high temperature) / (optimum exposure of sample stored at refrigerator) Evaluation criteria A: When the fluctuation rate of the optimal exposure is 0 to less than 3%, the storage stability is good. B: When the fluctuation rate of the optimal exposure is 3% or more, the storage stability is poor.

[0570]

[0571]

[0572]

[0573] As shown in Tables 7 to 9, it was confirmed that the resist compositions of Examples 1 to 35 had high sensitivity, were able to enhance both the effect of reducing roughness and the exposure latitude, and also had good storage stability.

[0574] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition comprising a resin component whose solubility in a developer changes due to the action of the acid, the resin component comprising a polymer having a group represented by the following general formula (I-1) at at least one end of the main chain: [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.] 2. R in the general formula (I-1) ２ 2. The resist composition according to claim 1, wherein the ionic group (i) is an ionic group represented by the following general formula (i-1): [In the formula, R Ａｒ１ is an aromatic group having at least an iodine atom as a substituent. １０ represents a divalent linking group or a single bond. ａｎ － is a sulfonate group (-SO ３ － ) or a carboxylate group (—COO － ) M ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. * represents a bond to the X.

3. R in the general formula (I-1) ２ is the ionic group (ii), and the ionic group (ii) is an ionic group represented by the following general formula (ii-1): [In the formula, R Ａｒ２ R is an aromatic group which may have a substituent. ２１ and R ２２ are each independently an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent, or R ２１ and R ２２ are bonded to each other to form a ring together with the sulfur atom in the formula. Ａｒ２ , R ２１ and R ２２ At least one of Y has at least an iodine atom as a substituent. ＡＮ － is a sulfonate anion or a carboxylate anion. * represents a bond to the X.

4. R in the general formula (I-1) ２ The resist composition according to claim 1, wherein the hydrocarbon group (iii) is an aromatic group having at least an iodine atom as a substituent.

5. A method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to any one of claims 1 to 4, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

6. A compound represented by the following general formula (I): [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. The plurality of R present in the formula １ , multiple Zs, multiple Xs, multiple Rs ２ may be the same or different. N is a nitrogen atom.

7. A radical polymerization initiator comprising the compound according to claim 6.

8. A polymer having a group represented by the following general formula (I-1) at at least one end of the main chain: [In the formula, R １ is a hydrocarbon group having 1 to 10 carbon atoms. Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group. R １ and Z may be bonded to each other to form a ring. X is a divalent linking group (excluding those containing a sulfide bond (-S-)) which may contain at least one group selected from the group consisting of -O-, -C(=O)-, -O-C(=O)-, -NH-C(=O)-, -NH-C(=NH)- and an alkylene group. R ２ is an ionic group (i) consisting of an anionic group having an iodine atom and its counter cation, an ionic group (ii) consisting of a cationic group having an iodine atom and its counter anion, or a hydrocarbon group (iii) having at least an iodine atom as a substituent. In the ionic group (i), the anionic group having an iodine atom is bonded to X. In the ionic group (ii), the cationic group having an iodine atom is bonded to X. * represents a bond.]

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