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

Abstract

To provide, e.g., a resist composition which makes it possible to achieve high sensitivity, increase a roughness reduction effect and an exposure latitude, and improve storage stability.SOLUTION: 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, provided that the anion group having an iodine atom or the cation group having an iodine atom is bonded to X.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resist composition, a method of forming a resist pattern, a compound, a radical polymerization initiator, and a polymer. [Background technology]

[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 lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with minute dimensions. To satisfy these requirements, a chemically amplified resist composition has been used, which contains a base component whose solubility in a developer changes due to the action of acid, and an acid generator component that generates acid upon exposure. In chemically amplified resist compositions, a polymeric compound having a plurality of structural units is generally used as the base component in order to improve lithography properties and the like.

[0004] The polymer compounds used in the base component are usually produced by radical polymerization of monomers having various functions. As the polymerization initiator in the radical polymerization, an azo-based polymerization initiator such as azobisisobutyronitrile (AIBN) is generally used, and the partial structure of the azo-based polymerization initiator is introduced into the terminal of the produced polymer compound. A polymer compound having an acid-dissociable group introduced as the partial structure at the main chain terminal, and a resist composition containing the polymer compound have been disclosed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-153686 Summary of the Invention [Problem to be solved by the invention]

[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 is becoming increasingly important 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 others. In addition, resist compositions are also required to have storage stability that prevents 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. [Means for solving the problem]

[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 the following general formula (I-1) at at least one end of the main chain:

[0009] [ka] [In the formula, R1 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)-, -OC(=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.]

[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] [ka] [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)-, -OC(=O)-, -NH-C(=O)-, -NH-C(=NH)-, and an alkylene group. R2 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 multiple R present in the formula 1 , multiple Z, multiple X, multiple R 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] [ka] [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)-, -OC(=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.] [Effects of the Invention]

[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. DETAILED DESCRIPTION OF THE INVENTION

[0017] In this specification and claims, the term "aliphatic" is defined as a relative concept to aromatic, and refers to groups, compounds, etc. that do not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. The "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrase "may have a substituent" includes both the case where a hydrogen atom (-H) is replaced with a monovalent group and the case where a methylene group (-CH2-) is replaced with a divalent group. The term "exposure" is a general concept that includes irradiation with radiation.

[0018] The term "acid-decomposable group" refers to a group having acid decomposability in which at least some of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases under the action of an acid include groups that decompose under 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 (-SO3H). More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0019] The term "acid-dissociable group" refers to either (i) a group having acid dissociability such that the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a portion of the bond is cleaved by the action of an acid, and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Thus, when the acid-dissociable group dissociates under the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, increasing the polarity. As a result, the polarity of the entire 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 that has film-forming ability. Organic compounds used as base components are broadly divided into non-polymers and polymers. Non-polymers typically have a molecular weight of 500 or more and less than 4000. Hereinafter, the term "low molecular weight compound" refers to a non-polymer with a molecular weight of 500 or more and less than 4000. Polymers typically have a molecular weight of 1000 or more. Hereinafter, the terms "resin," "high molecular weight compound," or "polymer" refer to a polymer with a molecular weight of 1000 or more. The molecular weight of a polymer is determined by the weight average molecular weight converted into 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, such as 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. αx ) is an atom or group other than a hydrogen atom. αx ) is substituted with a substituent containing an ester bond, or αx This also includes α-hydroxyacrylic esters in which the hydroxyl group is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylic ester.

[0022] The term "derivative" encompasses compounds in which the hydrogen atom at the α-position of the target compound is substituted with another substituent, such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of a hydroxyl group of a target compound, which may have the hydrogen atom at the α-position substituted with a substituent, is substituted with an organic group; and compounds in which a substituent other than a hydroxyl group is bonded to a target compound, which may have the hydrogen atom at the α-position substituted with a substituent. Unless otherwise specified, the α-position refers to the first carbon atom adjacent to the functional group. The substituents that 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 diastereomers. In such cases, a single chemical formula represents all isomers. These isomers may be used alone or as a mixture.

[0024] (Resist composition) In one embodiment of the resist composition, an acid is generated upon exposure, and the solubility in a developer is changed by the action of the acid. The resist composition contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes under 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 under the action of an acid, and the component (A1) contains a polymer having a specific group (a group represented by general formula (I-1)) containing 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 that is formulated separately from the component (A) may generate an acid upon exposure. Specifically, the resist composition of this embodiment may (1) further contain an acid generator component that generates acid upon exposure; (2) the component (A) may be a component that generates acid upon exposure; or (3) the component (A) may be a component that generates acid upon exposure and may 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 acid upon exposure and whose solubility in a developer changes due to the action of the acid." When the component (A) is a base component that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, it is preferable that the polymer is one that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid. As such a polymer, a copolymer having a structural unit that generates acid upon exposure can be used. As the structural unit that generates acid upon exposure, the structural unit (a5) and the structural unit (a6) described below can be used.

[0026] When a resist film is formed using the resist composition of this embodiment and then 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 action of the acid changes the solubility of the component (A) in a developer, 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 an alkaline development process in which an alkaline developer is used in the development treatment during resist pattern formation, or may be for a solvent development process in which a developer containing an organic solvent (organic developer) is used in the development treatment.

[0028] <Base material 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, allowing for good development contrast to be obtained not only in alkaline development processes but also in solvent development processes. Additionally, 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 of a high molecular weight compound and a low molecular weight compound other than the component (A1) may be used in combination with the component (A). The proportion of component (A1) in component (A) is preferably 25 mass% or more, more preferably 50 mass% or more, and even more preferably 75 mass% or more, or even 100 mass% based on the total mass of component (A). When this proportion is 25 mass% or more, the above-mentioned effects, good lithography properties, and a good resist pattern shape are more likely to be obtained.

[0029] About 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) contains a polymer (hereinafter also referred to as "component (A1-0)") having a group represented by general formula (I-1) described below at at least one end of the main chain. In the resist composition of this embodiment, the component (A1) may consist solely of the component (A1-0), or may consist of the component (A1-0) in combination with a polymer whose solubility in a developer changes under the action of acid (provided that this does not fall under the category of the component (A1-0); hereinafter, this may be referred to as the “component (A2)”).

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

[0031] [ka] [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)-, -OC(=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 The hydrocarbon group having 1 to 10 carbon atoms in the formula (I) may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and 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 aliphatic hydrocarbon groups (straight-chain or branched-chain alkyl groups) and aliphatic hydrocarbon groups containing a ring in the structure. The linear alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms, and most preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is particularly preferred. The branched alkyl group preferably has a carbon number of 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, and a neopentyl group, and an isopropyl group or a tert-butyl group is most preferred. Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of the aforementioned chain aliphatic hydrocarbon group, or a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of the aforementioned chain aliphatic hydrocarbon group. The cyclic aliphatic hydrocarbon group preferably has a carbon number of 3 to 8, more preferably 4 to 6. 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, such as an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or 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 group include those having 1 to 10 carbon atoms.

[0034] In the formula (I-1), R 1 and 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 ends of R and Z may be bonded to each other to form a ring. 1 and Z and R 1The 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 the cyclohexane formed by the carbon atom to which they 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)-, -OC(=O)-, -NH-C(=O)-, -NH-C(=NH)-, and an alkylene group. Examples of the divalent linking group for X (excluding those containing a sulfide bond (-S-)) include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0037] An optionally substituted divalent hydrocarbon group: The phrase "a hydrocarbon group having 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 optionally substituted divalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[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. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched 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. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. The chain aliphatic hydrocarbon group may or may not have a substituent, which may include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and an oxygen atom (═O).

[0039] Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of the aforementioned chain aliphatic hydrocarbon group, or a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of the chain aliphatic hydrocarbon group. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms, and examples of the monocycloalkane include cyclopentane and cyclohexane. The polycyclic group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane having 7 to 12 carbon atoms, and specific examples of the polycycloalkane 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. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which 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. 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 group or heteroarylene group); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (for example, biphenyl, fluorene, etc.); and groups in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group), in which one hydrogen atom has been substituted with an alkylene group (for example, 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. The aromatic 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).

[0041] Divalent linking groups containing heteroatoms: Examples of the divalent linking group containing a heteroatom include -O-, -C(=O)-, -OC(=O)-, -OC(=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)-, -S(=O)-O-, "-AO(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 heteroatom. 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 preferred are linear, branched, or aliphatic hydrocarbon groups which contain a ring in their structure.

[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 "AOB", 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 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 in 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 consists of only one of -O-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)-, X is preferably -OC(=O)- or -NH-C(=O)-. In this case, the carbon atom (C) in -OC(=O)- or the carbon atom (C) in -NH-C(=O)- is preferably R 1 and preferably directly bonded to the carbon atom to which Z is bonded. When X is a combination of any of -O-, -C(=O)-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)- as described above, and a divalent group (a divalent hydrocarbon group which may have a substituent, or a divalent linking group containing a hetero atom), X is preferably a combination of any of -O-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)-, and a divalent hydrocarbon group which may have a substituent; more preferably a combination of any of -O-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)-, and a linear or branched aliphatic hydrocarbon group having 1 to 5 carbon atoms; and even more preferably a combination of any of -O-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)-, and a methylene group or an ethylene group. The direction of the bond -OC(=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)-, -OC(=O)-, -NH-C(=O)-, -NH-C(=NH)-, and an alkylene group, and is composed of a combination of any of -O-, -C(=O)-, -OC(=O)-, -NH-C(=O)-, or -NH-C(=NH)- and a chain aliphatic hydrocarbon group (straight-chain or branched-chain aliphatic hydrocarbon group) having 1 to 10 carbon atoms. A combination of any of -O-, -OC(=O)-, -NH-C(=O)- or -NH-C(=NH)- with a linear or branched alkylene group having 1 to 10 carbon atoms is preferred; a combination of -OC(=O)- with a methylene group or an ethylene group; a combination of -C(=O)-O-, a methylene group or an ethylene group, and -NH-C(=O)-; and a combination of -O-, a methylene group or an ethylene group, and -NH-C(=O)- are particularly preferred.

[0046] In the above description of X, the direction of the bond in the divalent linking group does not matter. For example, -OC(=O)- can be -C(=O)-O-, and -NH-C(=O)- can be -C(=O)-NH-. The combination of -OC(=O)- and a methylene group or an ethylene group may be either -OC(=O)-(methylene group or ethylene group)- or -C(=O)-O-(methylene group or ethylene group)-. The 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-, -OC(=O)-(methylene group or ethylene group)-NH-C(=O)-, and -OC(=O)-(methylene group or ethylene group)-C(=O)-NH-. The combination of -O-, a methylene group or an ethylene group, and -NH-C(=O)- may be either -O-(methylene group or ethylene group)-NH-C(=O)- or -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, provided that 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. The anionic group is preferably a sulfonate group (-SO3 - ), 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] [ka] [In the formula, R Ar1 is an aromatic group having at least an iodine atom as a substituent. 10 is a divalent linking group or a single bond. an - is a sulfonate group (-SO3 - ) or carboxylate group (-COO - ) is. M m+ is an m-valent onium cation, where m is an integer of 1 or more, and * 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. R Ar1 The aromatic group may be monocyclic or polycyclic. The aromatic group preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, further preferably 6 to 15 carbon atoms, and particularly preferably 6 to 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 some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specifically, the aromatic group is preferably 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 Ar1 The aromatic group in the formula (I) 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, the number is preferably 2 or 3, and more preferably 3. From the viewpoint of reducing roughness, the number is preferably 1 or 2, and more preferably 2. R 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 above formula (i-1), L 10 is a divalent linking group or a single bond. L 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. L 10is 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 (-SO3 - ) or carboxylate group (-COO - )

[0056] Y an - is a sulfonate group (-SO3 - ), 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 )-SO3 - R Ar1 is R in the above formula (i-1) Ar1 is the same as Y 110 represents a divalent linking group or a single bond. V 10 represents a fluorinated alkylene group, an alkylene group, or a single bond. R 101 is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. R 102 is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. * indicates a bond to the X.

[0058] In the general formula, Y 110 Examples of the divalent linking group in Y include the same as the divalent linking group containing a hetero atom in X in the above formula (I-1). 110 is preferably an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-) or an oxycarbonyl group (-OC(=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) above. 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. V 10 is preferably a methylene group (-CH2-), -CH(CF3)-.

[0060] In the general formula, R 101 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, more preferably a fluorine atom. R 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 is the same as Y 120 represents a divalent linking group or a single bond. * indicates a bond to the X.

[0063] In the general formula, Y 120 Examples of the divalent linking group in include the same as the divalent linking group containing a hetero atom in X in the above formula (I-1). Y 120 represents an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-OC(=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, preferably a sulfonium cation or an iodonium cation, and m is an integer of 1 or more. Preferred cationic moieties ((M m+ ) 1 / m ) includes onium cations represented by the following general formulas (ca-1) to (ca-3), respectively.

[0065] [ka] [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. 210is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-.]

[0066] In the above general formulas (ca-1) to (ca-3), R 201 ~R 207 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 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] [ka] [In the formula, R' 201 are each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0068] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that 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 the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, 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. R' 201 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201 Specific examples of the aromatic hydrocarbon group in include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and 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.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0070] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 30 carbon atoms. Among these, the polycycloalkane includes adamantane, norbornane, isobornane, tricyclo[5.2.1.0], and the like. 2,6 More preferred are 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.

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

[0073] Also, R' 201 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle, etc. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, -SO2- containing cyclic groups represented by the general formulae (b5-r-1) to (b5-r-4) described below, and other heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16).

[0074] [ka]

[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, 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. As the halogen atom as a substituent, a fluorine atom is preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

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

[0077] An optionally substituted chain alkenyl group: R' 201The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a 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 chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are 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' 201 In addition to the above, the optionally substituted cyclic group, the optionally substituted chain alkyl group, or the optionally substituted chain alkenyl group may also be the same as the acid-dissociable group represented by formula (a1-r-2) described below, as the optionally substituted cyclic group or the optionally substituted chain alkyl group.

[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 formulas (a2-r-1) to (a2-r-7) described below, and an —SO2- containing cyclic group represented by each of the general formulas (b5-r-1) to (b5-r-4) described below are preferred.

[0081] In the above general formulas (ca-1) to (ca-3), R 201 ~R203 , R 206 ~R 207 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may not contain a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO2-, -SO3-, -COO-, -CONH-, or -N(R N )-(applicable 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 209 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0083] R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 210The -SO2- containing cyclic group in 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), with "-SO2- containing polycyclic groups" being preferred and groups represented by general formula (b5-r-1) being more preferred.

[0084] [ka] [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 an -SO2- 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, and 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, in which "Ac" represents an acetyl group.

[0088] [ka]

[0089] [ka]

[0090] [ka]

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

[0092] [ka]

[0093] [ka]

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

[0095] [ka]

[0096] [ka]

[0097] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent, and the substituent is the same as R201 ~R 207 , and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the group

[0098] [ka]

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

[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] [ka]

[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 achieving high 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 the above chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84).

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

[0104] [ka]

[0105] [ka]

[0106] Regarding the ionic group (ii): R 2 The ionic group (ii) in the formula (I-1) is composed of a cationic group having an iodine atom and its counter anion, provided that 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. The cationic group is preferably an onium cation, more preferably a sulfonium cation. The counter anion is preferably a sulfonate anion or a carboxylate anion.

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

[0108] [ka] [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 22At 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 is an aromatic group which may have a substituent. R Ar2 The aromatic group may be monocyclic or polycyclic. The aromatic group preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, further preferably 6 to 15 carbon atoms, and particularly preferably 6 to 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 some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specifically, the aromatic group is preferably 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 22are bonded to each other to form a ring together with the sulfur atom in the formula. R 21 and R 22 As the group, R in the above general formula (ca-1) 201 ~R 203 Similar examples include R 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 the formula (I) preferably has 2 to 10 carbon atoms. R 21 and R 22 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 above general formulae (ca-r-1) to (ca-r-7).

[0113] However, R Ar2 , R 21 and R 22 At least one of the groups has at least an iodine atom as a substituent. R 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] [ka] [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, provided that Y 101 and V 101 cannot simultaneously be a single bond. In formula (d1-an-2), Rd 2 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. 2 In this case, no fluorine atom is bonded to the carbon atom adjacent to the S atom.

[0117] ·About 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] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group is preferably saturated.

[0119] R 101 The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The number of carbon atoms in the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, 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. R 101 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R 101 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and a group 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 (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0120] R 101 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 30 carbon atoms. Among these, the polycycloalkane includes adamantane, norbornane, isobornane, tricyclo[5.2.1.0], and the like. 2,6 More preferred are 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.

[0121] Among them, R 101 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or 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. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. 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. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0123] Also, R 101 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle, etc. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, -SO2- containing cyclic groups represented by the general formulae (b5-r-1) to (b5-r-4) above, and heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) above.

[0124] R 101 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as 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. As the halogen atom as a substituent, a fluorine atom, a bromine atom, or an iodine atom is preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[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 polycyclic skeleton of a bridged ring system to which one or more aromatic rings are fused. Specific examples of the bridged ring system polycycloalkane include bicycloalkanes such as bicyclo[2.2.1]heptane (norbornane) and bicyclo[2.2.2]octane. The fused ring group is preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicycloalkane, and more preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicyclo[2.2.2]octane. 101 Specific examples of the fused cyclic group in the formula (b-an-1) include those represented by the following formulas (r-br-1) to (r-br-2). In the formula, * represents Y in formula (b-an-1). 101 represents a bond bonded to

[0126] [ka]

[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, and an alicyclic hydrocarbon group. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group are the same as those described above in R 101 Examples of the substituents for the cyclic group in the formula (I) include the same as those listed above. Examples of the aromatic hydrocarbon group as a substituent of the fused ring group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc.), and 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 ring group include groups in which one hydrogen atom has been removed from a monocycloalkane such as cyclopentane or cyclohexane; 2,6 ] groups in which one hydrogen atom has been removed from a polycycloalkane such as decane, tetracyclododecane, or tetracyclododecane; lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below; —SO2- containing cyclic groups represented by the general formulae (b5-r-1) to (b5-r-4) above; and heterocyclic groups represented by the chemical formulae (r-hr-7) to (r-hr-16) above.

[0128] A chain alkyl group which may have a substituent: R 101 The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10. 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] An optionally substituted chain alkenyl group: R 101 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, 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 chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are 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 101 is a single bond or a divalent linking group containing an oxygen atom. Y 101 is a divalent linking group containing an oxygen atom, 101 may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms. Examples of the divalent linking group containing an oxygen atom include 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), R in the above formula (b-an-1) 101 The bond to V' in the following general formulas (L-al-1) to (L-al-8) is 101 is.

[0133] [ka] [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 may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 Some of the methylene groups in the alkylene group in the formula may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is preferably 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), 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 anions include those represented by any of the following general formulae (an-1) to (an-3).

[0139] [ka] [In the formula, R” 101 R" is an aliphatic cyclic group which may have a substituent, a monovalent heterocyclic group represented by the above chemical formulas (r-hr-1) to (r-hr-6), a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), a chain alkyl group which may have a substituent, or an aromatic cyclic group which may have a substituent. 102 R" is an aliphatic cyclic group which may have a substituent, a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), a lactone-containing cyclic group represented by each of the general formulas (a2-r-1), (a2-r-3) to (a2-r-7) described below, or an -SO2- containing cyclic group represented by each of the above general formulas (b5-r-1) to (b5-r-4). 103 V" is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. 101 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 101The 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 The alkyl group is preferably one of the groups exemplified as the chain alkyl group in the above formula. R” 103 The chain alkenyl group which may have a substituent is represented by R 101 Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0143] ·Anions in the (d1-2) component Anions represented by the general formula (d1-an-2) In the above formula (d1-an-2), Rd 2 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and 101 The same can be mentioned. 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). This makes the anion represented by the formula (d1-an-2) an appropriately weak acid anion, improving the quenching ability to control the diffusion of the acid.

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

[0145] Road 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] [ka]

[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] [ka] [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] ·About the anion represented by the general formula (d1-an-1) In the above 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 The same can be mentioned. 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 that 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 formulas (a2-r-1) to (a2-r-8) 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). Examples of the aliphatic cyclic group include adamantane, norbornane, isobornane, tricyclo[5.2.1.0 2,6 It is more preferable that the cycloalkane 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 straight-chain alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched-chain alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

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

[0153] [ka]

[0154] Specific examples of the group represented by general formula (I-1) are shown below: 2 Specific examples where is the ionic group (ii) are shown below: In the formula, [ ] indicates a terminal structure of the polymer main chain.

[0155] [ka]

[0156] [ka]

[0157] Regarding hydrocarbon group (iii): R 2 The hydrocarbon group (iii) in the formula (I) is a hydrocarbon group having at least an iodine atom as a substituent. R 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 are the same as those in the above. 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 having at least an iodine atom as a substituent (e.g., a phenyl group, a naphthyl group, etc.). 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 viewpoint of sensitivity or exposure latitude, the number is preferably 2 or 3, and more preferably 3. From the viewpoint of reducing roughness, the number is preferably 1 or 2, and more preferably 2.

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

[0160] [ka]

[0161] The component (A1-0) may be any polymer having a group represented by general formula (I-1) above (hereinafter referred to as "terminal group (I-1)") at at least one end of its main chain, and the components other than the terminal group (I-1) may be similar to those of the resin components (base resins) typically used as substrate components for chemically amplified resists. As such a component (A1-0), a compound having a structural unit (a1) containing an acid-decomposable group whose polarity increases upon the action of an acid is preferred. The preferred component (A1-0) may contain, in addition to the structural unit (a1), other structural units as necessary.

[0162] <Constituent unit (a1)> The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity increases when acted upon by an acid. The component (A1-0) preferably contains the structural unit (a1).

[0163] Examples of the acid-dissociable group include those that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed for use in base resins for 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," which are explained 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 groups").

[0165] [ka] [In the formula, Ra' 1 , Ra' 2 is a hydrogen atom or an alkyl group. 3 is a hydrocarbon group, and Ra' 3 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 At least one of these is preferably a hydrogen atom, and both are more preferably hydrogen atoms. Ra' 1 or Ra' 2When 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 an alkyl group having 1 to 5 carbon atoms is preferred. Specific examples include linear or branched alkyl groups. More specific examples include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups, with methyl and ethyl groups being more preferred, and methyl being particularly preferred.

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

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

[0170] Ra' 3 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, further preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which 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. Ra' 3 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle; a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 to 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, or -RP2-COOH (hereinafter, these substituents are also collectively referred to as "Rax5"). where R P1 is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. P1 and R P2 Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the alicyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic hydrocarbon group may have one or more of the above-mentioned substituents, or may have one or more of each of multiple types of the above-mentioned substituents. Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group; and polycyclic aliphatic saturated hydrocarbon groups such as a bicyclo[2.2.2]octanyl group, tricyclo[5.2.1.02,6]decanyl group, tricyclo[3.3.1.13,7]decanyl group, tetracyclo[6.2.1.13,6.02,7]dodecanyl group, and adamantyl group. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene.

[0172] Ra' 3 But Ra' 1 , Ra' 2 When the cyclic group is bonded to any of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, and 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-type acid-labile group: Among the polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2). Among the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group may be referred to as "tertiary alkyl ester-type acid-dissociable groups" hereinafter for convenience.

[0174] [ka] [In the formula, Ra' 4 ~Ra' 6 are each a hydrocarbon group, and Ra' 5 , Ra' 6 may be bonded to each other to form a ring.

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

[0176] Ra' 5 and Ra' 6 and (a1-r2-3) are preferably substituted or unsubstituted by the alkyl group. On the other hand, Ra' 4 ~Ra' 6 When are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0177] [ka] [In formula (a1-r2-1), Ra' 10 Ra' represents a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. 11 Ra' 10 represents a group that forms an aliphatic cyclic group together with the carbon atom to which Ya is bonded. In formula (a1-r2-2), Ya is a carbon atom. Xa is a group that forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Ra 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 these 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 which forms an aliphatic cyclic group together with Yaa. Ra104 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 in 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 the formula (I) has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. Ra' 10 In the formula (I), the branched alkyl group is the above-mentioned Ra' 3 The same can be mentioned.

[0180] Ra' 10 The alkyl group in 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 (e.g., methylene groups) constituting the alkyl group may be substituted with a heteroatom-containing group. Examples of heteroatoms include oxygen, sulfur, and nitrogen atoms. Examples of heteroatom-containing groups include (-O-), -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -S-, -S(=O)2-, and -S(=O)2-O-.

[0181] In formula (a1-r2-1), Ra' 11 (Ra' 10The aliphatic cyclic group formed together with the carbon atom to which the carbon atom is bonded is represented by Ra' in formula (a1-r-1). 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 such groups include groups in which one or more hydrogen atoms have been further removed from the cyclic monovalent hydrocarbon group (aliphatic hydrocarbon group) shown above. The cyclic hydrocarbon group formed by Xa together with Ya may have a substituent. The substituent may be any of the above-mentioned Ra' 3 Examples of the substituents include the same as those that the cyclic hydrocarbon group in the above may have. In formula (a1-r2-2), Ra 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. Ra 101 ~Ra 103 In the formula (I), examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group; 2,6 ]decanyl group, tricyclo[3.3.1.1 3,7 ]decanyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Examples thereof include polycyclic aliphatic saturated hydrocarbon groups such as a dodecanyl group and an adamantyl group. Ra 101 ~Ra 103Among 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 preferred, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferred, with a hydrogen atom being particularly preferred.

[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: 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 The groups mentioned above as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups. In formula (a1-r2-3), Ra 104 Examples of the aromatic hydrocarbon group in the formula 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 include a methyl group, an ethyl group, a propyl group, a hydroxy group, a carboxy group, a halogen atom, an alkoxy group (such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group), and an alkyloxycarbonyl group.

[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, the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Ra 101 ~Ra 103 Examples include the same monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms as in the above. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted. Ra' 12 and Ra' 13 Among these, alkyl groups having 1 to 5 carbon atoms are preferred, alkyl groups having 1 to 5 carbon atoms are more preferred, methyl groups and ethyl groups are even more preferred, and methyl groups are particularly preferred. The above Ra' 12 and Ra' 13 When the chain saturated hydrocarbon group represented by the formula: is substituted, examples of the substituent include the above-mentioned Ra x5 The same groups as those shown below can be mentioned.

[0188] In formula (a1-r2-4), Ra' 14 Ra' is a hydrocarbon group which may have a substituent. 14 The hydrocarbon group in the formula (I) includes a linear or branched alkyl group, or a cyclic hydrocarbon group.

[0189] Ra' 14The 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, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0190] Ra' 14 The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, 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. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically 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. Ra' 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 is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. Ra' in formula (a1-r2-4) 14 When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be any one of the 1st, 2nd, or 9th position of the anthryl group.

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

[0195] [ka]

[0196] [ka]

[0197] [ka]

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

[0199] [ka]

[0200] [ka]

[0201] [ka]

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

[0203] [ka]

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

[0205] [ka]

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

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

[0208] In formula (a1-r-3), Ra' 7 ~Ra' 9are 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-labile group: Among the 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] [ka] [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' 12 The hydrocarbon group in Ra' 3 The same can be mentioned. In the formula, Ra' 11a and Ra' 11b The alkyl group in Ra' is 1 The alkyl groups in the above formula (I) are the same as those in the above formula (I). In the formula, Ra' 10 and Ra' 12 The hydrocarbon group in 11a and Ra' 11bThe 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, which may be a polycyclic ring, a monocyclic ring, an alicyclic ring, or an aromatic ring. The alicyclic and aromatic rings may contain heteroatoms.

[0213] Ra' 10 and Ra' 11a or Ra' 11b Among the above, the ring formed by bonding together is preferably a monocycloalkene, a ring in which some of the carbon atoms of a monocycloalkene are substituted with heteroatoms (oxygen atoms, sulfur atoms, etc.), or a monocycloalkadiene, more preferably a cycloalkene having 3 to 6 carbon atoms, and more preferably cyclopentene or cyclohexene.

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

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

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

[0218] [ka]

[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, preferred structural units (a1) are structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Preferred specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1), (a1-2), or (a1-3).

[0221] [ka] [wherein 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 between 0 and 2. 1 is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). 1 is n a2 + is a monovalent hydrocarbon group. n a2 is an integer between 1 and 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 Rz 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. n is an integer of 0 or more, provided that n≦q×2+4.

[0222] In the formulas (a1-1) to (a1-3), the alkyl group of 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group of 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 of 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group of 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

[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 specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in its 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 straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)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. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

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

[0227] Va 1 The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such aromatic hydrocarbon groups preferably have 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 substituents. Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (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 hydrogen atom has been further removed from the aryl group in an arylalkyl group, such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[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 in a2 The monovalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group refers to 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 their structure, and groups that combine linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in their structure. The n a2 The +1 valence is preferably 2 to 4, more preferably 2 or 3. In the formula (a1-2), Ra 2 is preferably an acid-dissociable group represented by the above general formula (a1-r-1).

[0230] In the formula (a1-3), Ya 001The 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. Ya 001 is preferably an ester bond [-C(=O)-O-, -OC(=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 is more preferably a combination of an ester bond [-C(=O)-O-, -OC(=O)-] and a linear alkylene group, or a single bond, and even 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. Ya 01 Among the above, Ya is preferably an ester bond [-C(=O)-O-, -OC(=O)-], an ether bond (-O-), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. 01 is more preferably a combination of an ester bond [-C(=O)-O-, -OC(=O)-] and a linear alkylene group, or a single bond, and even 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 the formula (I) 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. Rz 01 The halogen atom in Rz is preferably an iodine atom. 01 The halogen atom of the halogenated alkyl group in the formula (I) is preferably a fluorine atom, an iodine atom, or a bromine atom, and more preferably a fluorine atom. Rz 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 0 to 5, more preferably 0 to 3, and even more preferably 1 or 2. When n is an integer of 2 or more, Rz 01 may be the same as or different from each other. 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-Ra 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] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[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] [ka]

[0247] [ka]

[0248] [ka]

[0249] [ka]

[0250] [ka]

[0251] As the structural unit (a1), a structural unit represented by the above formula (a1-1) or a structural unit represented by the above formula (a1-3) is more preferred, as these tend to further improve the properties (sensitivity, shape, etc.) in electron beam or EUV lithography. Among these, the 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] [ka] [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 and Va in the formula (a1-1). 1 and n a1 is the same as:

[0255] The acid-dissociable group represented by 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, since this enhances reactivity and is suitable for use with EB or EUV.

[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) 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 %, based on the total (100 mol %) of all structural units constituting the component (A1-0). By ensuring that the proportion of the structural unit (a1) is at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity, roughness, exposure latitude, and resolution are improved. On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0257] Other structural units The preferred component (A1-0) may contain, in addition to the structural unit (a1) described above, other structural units as necessary. Examples of other structural units include a 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] [ka] [In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.] x1 is a single bond or a divalent linking group. x1 is an aromatic hydrocarbon group which may have a substituent. ax1 is an integer greater than or equal to 1.]

[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. In the above chemical formula, Ya x1 The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

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

[0263] Aliphatic hydrocarbon groups The 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 a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in its structure.

[0264] Linear or branched aliphatic hydrocarbon groups The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)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. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[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 rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, and 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, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and still 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 have been substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0268] Aromatic hydrocarbon groups The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still 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 substituent. 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. 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 hydrogen atom has been further 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 to 2 carbon atoms, and particularly preferably 1 carbon atom.

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

[0270] Divalent linking groups containing heteroatoms: Examples of the divalent linking group containing a hetero atom include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -OY22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -, wherein Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 1 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, an acyl group, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. General formula-Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -Medium, 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. Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred. Y 22is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 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 - is a group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) b’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, 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-, -OC(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -OC(=O)-].

[0272] In the formula (a10-1), Wa x1 is an aromatic hydrocarbon group which may have a substituent. Wa x1 The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ax1Examples of the aromatic ring include groups 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 aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Also, Wa x1 The aromatic hydrocarbon group in (n) is selected from aromatic compounds containing an aromatic ring which may have two or more substituents (for example, biphenyl, fluorene, etc.). ax1 +1) hydrogen atoms may also be removed. Among the above, Wa x1 As examples, benzene, naphthalene, anthracene, or biphenyl (n ax1 A group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ax1 A group obtained by removing (n +1) hydrogen atoms 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. x1The 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, further 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. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0276] [ka]

[0277] [ka]

[0278] [ka]

[0279] The structural unit (a10) 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 (a10), although it is preferable for the component (A1-0) to contain the structural unit (a10). When the component (A1-0) contains the structural unit (a10), the proportion of the structural unit (a10) within the component (A1-0) relative to the total (100 mol%) of all structural units constituting the component (A1-0) is preferably within a range from 20 to 80 mol%, more preferably from 25 to 70 mol%, even more preferably from 30 to 60 mol%, and particularly preferably from 30 to 50 mol%. By ensuring that the proportion of the structural unit (a10) is at least as large as the lower limit of the aforementioned preferred range, sensitivity can be further improved, while by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, it becomes easier to achieve a balance with 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) that contains a lactone-containing cyclic group (provided that this does not fall under the category of 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, for example, by 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 containing a ring (lactone ring) containing -OC(=O)- in its ring skeleton. The lactone ring is counted as the first ring, and a group consisting of only a lactone ring is called a monocyclic group. If a group further contains other ring structures, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. The lactone-containing cyclic group in the structural unit (a2) is not particularly limited and any suitable group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0282] [ka] [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 the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' 21 The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the alkoxy group in the formula (1) is preferably linear or branched. 21 Examples of the alkyl group include a group in which the alkyl groups mentioned above are linked to an oxygen atom (—O—). Ra' 21 The halogen atom in is preferably a fluorine atom. Ra' 21 The halogenated alkyl group in the formula Ra' is 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' 21 In the -COOR" and -OC(=O)R" groups, R" is a hydrogen atom, an alkyl group, or a lactone-containing cyclic group. The alkyl group in R'' may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, a tricycloalkane, or a tetracycloalkane; more specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; adamantane, norbornane, isobornane, or tricyclo[5.2.1.0 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) above. Ra' 21 The hydroxyalkyl group in the formula (I) preferably has 1 to 6 carbon atoms, and specifically, the hydroxyalkyl group in the formula (I) is preferably the hydroxyalkyl group in the formula (I) 21 In the above formula, 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 straight-chain or branched-chain 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-CH2-, -CH2-O-CH2-, -S-CH2-, and -CH2-S-CH2-. A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

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

[0288] [ka]

[0289] [ka]

[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 particularly preferred. Such a structural unit (a2) is preferably a structural unit represented by the following general formula (a2-1).

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

[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.

[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 above formula (a2-1), Ra 21 is a lactone-containing cyclic group. Ra 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 within 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 (a2). When the component (A1-0) contains the structural unit (a2), the proportion of the structural unit (a2) relative to the total (100 mol%) of all structural units constituting the component (A1-0) is preferably 1 to 20 mol%, more preferably 1 to 15 mol%, and even more preferably 1 to 10 mol%. By ensuring that the proportion of the structural unit (a2) is at least as large as the lower limit of the aforementioned preferred range, the effects previously described can be fully achieved by including the structural unit (a2). On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, and various lithography properties can be improved.

[0298] Regarding the structural unit (a5) that generates an acid upon exposure: The component (A1-0) may or may not include a structural unit (a5) that generates acid upon exposure. Known structural units 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) below. Suitable examples of the structural unit (a5) include structural units represented by general formula (a5-1) shown below.

[0299] [ka] [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. 50is a divalent hydrocarbon group which may have a substituent. a5 is an integer between 0 and 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 part} In the above 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. R 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 the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. 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 above formula (a5-1), La 50 is a divalent linking group or a single bond. La 50The divalent linking group in the formula 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, and each of these groups is the same as those described above for Ya x1 The divalent linking group is the same as the optionally substituted divalent hydrocarbon group and the divalent linking group containing a hetero atom exemplified in the above. Among the above, La 50 is preferably an ester bond [-C(=O)-O-, -OC(=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-, -OC(=O)-] or a single bond, and further preferably an ester bond [-C(=O)-O-, -OC(=O)-].

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

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

[0304] Linear or branched aliphatic hydrocarbon groups The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)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. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[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 rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, and 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, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and 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, 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, with a fluorine atom being 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 have been substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0308] ··Ra 50 Aromatic hydrocarbon groups in The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The 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 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 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 (arylene groups or heteroarylene groups) in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle; 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 (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., groups in which one hydrogen atom has been further 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 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0309] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and 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 substituting the hydrogen atom of the cyclic aliphatic hydrocarbon group.

[0310] In the formula (a5-1), n a5 is an integer between 0 and 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 which may have a substituent. Or, among the above, Ra 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 above formula (a5-1), La 51 is a divalent linking group. La 51 Examples 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. A sulfonyl group (-SO2-) may be further linked to this combination. Examples of such divalent linking groups include 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) 50 The bond to V' in the following general formulas (L-al-1) to (L-al-8) is 101 is.

[0313] [ka] [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' 102The 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 may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102 Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 In the 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 is preferred, and a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group is more preferred.

[0316] La 51As for L-al-1, 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-al-1) to (L-al-5) and (L-al-8) are more preferable, and the linking group represented by (L-al-3) or (L-al-8) is even more preferable.

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

[0318] In the above formula (a5-1), Ra 51 and Ra 52 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group. Ra 51 and Ra 52 The fluorinated alkyl group in each of the above is preferably a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a trifluoromethyl group. In the above formula (a5-1), SO3 - Ra bonded to the carbon atom adjacent to 51 and Ra 52 From 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 1, 2, or 3 is preferable.

[0320] {cation part} In the above formula (a5-1), M' m+ represents an m-valent onium cation. Among these, M' 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') in the formula (a5-1) 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 achieving high sensitivity, the preferred cation represented by the formula (ca-1) is 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 above chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84), respectively, is particularly preferred.

[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 above general formula (a5-1). m+ is the same as:

[0324] [ka]

[0325] [ka]

[0326] [ka]

[0327] [ka]

[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) within the component (A1-0) relative to the total (100 mol %) of all structural units constituting the component (A1-0) is preferably 5 to 25 mol %, more preferably 10 to 20 mol %, and even more preferably 15 to 20 mol %. When the proportion of the structural unit (a5) is at least as large as the lower limit of the above-mentioned preferred range, it becomes easier to achieve even higher sensitivity and improved resolution, while when it is at most the upper limit of the above-mentioned preferred range, it becomes easier to achieve a balance with other structural units.

[0329] Regarding the structural unit (a6) having acid diffusion control properties: The structural unit (a6) is a structural unit that has the ability to control acid diffusion. 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 above general formula (a5-1).m+ is the same as:

[0331] [ka]

[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) within the component (A1-0) relative to the total (100 mol %) of all structural units constituting the component (A1-0) is preferably within a range from 1 to 20 mol %, more preferably from 2 to 15 mol %, and even more preferably from 3 to 10 mol %. When the proportion of the structural unit (a6) is at least as large as the lower limit of the above-mentioned preferred range, even higher sensitivity can be easily achieved, while when it is at most the upper limit of the above-mentioned preferred range, it is easier to achieve a balance with other structural units.

[0333] Regarding the structural unit (a8) derived from the 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 contain the structural unit (a8).

[0334] [ka] [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 R may form a condensed ring. 1 R 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 between 1 and 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 consisting of only a polymerizable group, or may be a group consisting 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 heteroatom. 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 A group represented by the formula - is preferred. 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 Polymerizable group of the site and Ya x2 and the fused ring formed by W 2 Other groups than the polymerizable group at the Ya site x2 and a fused ring formed by Ya 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. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0339] [ka]

[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 within 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 amount 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 amount (100 mol %) of all structural units that make up the component (A1-0).

[0342] The component (A1-0) contained in the resist composition may use either a single type of compound, or a combination of two or more types of compounds. In the resist composition of this embodiment, the component (A1-0) is a polymer that has a “terminal group (I-1)” on at least one end of its main chain. 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 having the terminal group (I-1) and consisting of the structural unit (a1) and the structural unit (a10); a polymeric compound having the terminal group (I-1) and consisting of the structural unit (a1), the structural unit (a10), and the structural unit (a5); a polymeric compound having the terminal group (I-1) and consisting of the structural unit (a1), the structural unit (a10), and the structural unit (a6); and a polymeric compound having the terminal group (I-1) and consisting of the structural unit (a1), the structural unit (a10), the structural unit (a5), and the structural unit (a6).

[0343] With regard to 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 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 polymer compound is preferably 25 to 75 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0344] With regard to 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) 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) in the polymer compound is preferably 20 to 45 mol %, more preferably 25 to 45 mol %, and even more preferably 30 to 40 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a5) in the polymer compound is preferably 5 to 30 mol %, more preferably 5 to 25 mol %, and even more preferably 10 to 20 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0345] With regard to 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) within the polymeric compound is preferably 30 to 70 mol %, more preferably 40 to 60 mol %, and even more preferably 45 to 55 mol %, relative to the total (100 mol %) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) in the polymer compound is preferably 29 to 55 mol %, more preferably 38 to 50 mol %, and even more preferably 42 to 50 mol %, based on the total (100 mol %) of all structural units constituting the polymer 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.

[0346] With regard to 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) 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) in the polymer compound is preferably 20 to 35 mol %, more preferably 23 to 40 mol %, and even more preferably 27 to 35 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a5) in the polymer compound is preferably 4 to 25 mol %, more preferably 5 to 20 mol %, and even more preferably 10 to 20 mol %, based on the total (100 mol %) of all structural units constituting the polymer 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] The component (A1-0) can be produced, for example, by dissolving the monomers that derive the respective structural units in a polymerization solvent, adding a selected radical polymerization initiator that will result in at least one end of the main chain of the polymer becoming the terminal group (I-1), and polymerizing the resulting polymer. Alternatively, the component (A1-0) can be produced by dissolving a monomer that derives the structural unit (a1), a monomer that derives the structural unit (a10), and a monomer that derives any structural unit (for example, the structural unit (a5), the structural unit (a6), etc.) in a polymerization solvent, adding a selected radical polymerization initiator that will result in at least one end of the main chain of the polymer becoming the terminal group (I-1), polymerizing, and then carrying out a deprotection reaction.

[0348] In 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] [ka] [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)-, -OC(=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 multiple R present in the formula 1 , multiple Z, multiple X, multiple R 2 may be the same or different. N is a nitrogen atom.

[0350] In the formula (I), R 1 , Z, X, R 2 is R in the above formula (I-1). 1 , Z, X, R 2 are the same as In addition, the plurality of R 1 , multiple Z, multiple X, multiple R 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] [ka]

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

[0354] [ka]

[0355] [ka]

[0356] [ka]

[0357] [ka]

[0358] [ka]

[0359] [ka]

[0360] The weight average molecular weight (Mw) of the 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 the component (A1-0) is no more than the upper limit of the aforementioned preferred range, the compound will have sufficient solubility in a resist solvent for use as a resist. On the other hand, when it is at least the lower limit of the aforementioned preferred range, the compound will have good dry etching resistance and the cross-sectional shape of the resist pattern will be excellent. The dispersity (Mw / Mn) of the component (A1-0) is not particularly limited, but is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.0, and particularly preferably from 1.0 to 2.0, where Mn represents the number average molecular weight.

[0361] About 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 an acid. The components (A2) and (A1-0) differ from each other at least in the structure of the terminal group at the end of the main chain. This component (A2) preferably has the structural unit (a1) described above that contains an acid-decomposable group whose polarity increases when exposed to an acid. A preferred component (A2) may have other structural units in addition to the structural unit (a1), as necessary. Examples of other structural units include the aforementioned structural unit (a10), structural unit (a2), structural unit (a5), structural unit (a6), and structural unit (a8).

[0362] The component (A2) contained in the resist composition may use either a single type of compound, or a combination of two or more types of compounds. In the resist composition of this embodiment, 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] With regard to 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 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 polymer compound is preferably 25 to 75 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0364] With regard to 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) 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) in the polymer compound is preferably 20 to 45 mol %, more preferably 25 to 45 mol %, and even more preferably 30 to 40 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a5) in the polymer compound is preferably 5 to 30 mol %, more preferably 5 to 25 mol %, and even more preferably 10 to 20 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound.

[0365] With regard to 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) within the polymeric compound is preferably 30 to 70 mol %, more preferably 40 to 60 mol %, and even more preferably 45 to 55 mol %, relative to the total (100 mol %) of all structural units constituting the polymeric compound. The proportion of the structural unit (a10) in the polymer compound is preferably 29 to 55 mol %, more preferably 38 to 50 mol %, and even more preferably 42 to 50 mol %, based on the total (100 mol %) of all structural units constituting the polymer 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.

[0366] With regard to the component (A2), 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) 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) in the polymer compound is preferably 20 to 35 mol %, more preferably 23 to 40 mol %, and even more preferably 27 to 35 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a5) in the polymer compound is preferably 4 to 25 mol %, more preferably 5 to 20 mol %, and even more preferably 10 to 20 mol %, based on the total (100 mol %) of all structural units constituting the polymer 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] The component (A2) can be produced by dissolving the monomers that derive the respective structural units in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing the resulting mixture. Alternatively, the component (A2) can be produced by dissolving a monomer that derives the structural unit (a1), a monomer that derives the structural unit (a10), and a monomer that derives any structural unit (for example, the structural unit (a5), the 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 polymerization, a chain transfer agent such as HS-CH2-CH2-CH2-C(CF3)2-OH may be used in combination to introduce a -C(CF3)2-OH group to the terminal. Copolymers incorporating hydroxyalkyl groups in which some of the alkyl group's hydrogen atoms have been substituted with fluorine atoms are effective in reducing development defects and LER (line edge roughness: unevenness on the line sidewalls).

[0368] The weight average molecular weight (Mw) of the 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 the component (A2) is no more than the upper limit of the aforementioned preferred range, the compound exhibits sufficient solubility in a resist solvent for use as a resist. On the other hand, when the Mw is at least the lower limit of the aforementioned preferred range, the compound exhibits good dry etching resistance and excellent cross-sectional shape of the resist pattern. The dispersity (Mw / Mn) of the component (A2) is not particularly limited, but is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.0, and particularly preferably from 1.0 to 2.0, where Mn represents the number average molecular weight.

[0369] In the resist composition of this embodiment, the component (A1) may consist of only 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, it is likely that the sensitivity, roughness reduction effect, and exposure latitude are all improved, and the storage stability of the resist composition is also likely to be improved.

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

[0371] About ingredient (A3) The resist composition of this embodiment may also use, as the component (A), a base component (hereafter referred to as “component (A3)”) that does not fall under the category of the component (A1) and whose solubility in a developer changes upon the action of an acid. There are no particular restrictions on the component (A3), and it can be selected from the many conventional base components for 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 ingredients> 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. There are no particular restrictions on the component (B), and any of the acid generators 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. Component (B) may be contained in the form of a compound, or in the form of a compound incorporated into component (A1) as the structural unit (a5), or 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] 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)").

[0377] [ka] [In the formula, R 101 and R 104 ~R 108 R each independently represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. 104 and R 105 R may be bonded to each other to form a ring structure. 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 101is a divalent linking group containing an oxygen atom or a single bond. 101 ~V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group, provided that Y 101 and V 101 cannot be a single bond at the same time. 101 ~L 102 are each independently a single bond or an oxygen atom. 103 ~L 105 are each independently a single bond, —CO— or —SO2—; m is an integer of 1 or more; and M' m+ is an m-valent onium cation.

[0378] {anion part} 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

[0379] 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 of the above formulas (an-1) to (an-3).

[0380] 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, R104 , R 105 may be bonded to each other to form a ring. R 104 , R 105 is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and even more preferably 1 to 3 carbon atoms. 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 The same can be mentioned. In formula (b-2), L 101 , L 102 are each independently a single bond or an oxygen atom.

[0381] 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 The same can be mentioned. In formula (b-3), L 103 ~L 105 are each independently a single bond, —CO— or —SO2—.

[0382] Among the above, the anion moiety of the component (B) is preferably the anion in the component (b-1), and more preferably the anion represented by the above formula (an-1).

[0383] {cation part} 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.

[0384] The cation moiety of 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).

[0385] In the resist composition of this embodiment, as the component (B), one type of compound may be used alone, 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 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, per 100 parts by mass of the component (A). By ensuring that the amount of component (B) falls within this preferred range, it becomes easier to obtain a homogeneous solution when the individual components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition becomes excellent, which is advantageous.

[0386] <Base component (D)> The resist composition of this embodiment may contain, in addition to the component (A), a base component (component (D)) that traps the acid generated upon exposure (i.e., controls the diffusion of the acid). The component (D) functions as a quencher (acid diffusion controller) that traps the 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 acid diffusion controllability, and a nitrogen-containing organic compound (D2) (hereinafter referred to as "component (D2)") that does not fall under the category of component (D1). Among these, the photodegradable base (component (D1)) is preferred because it is likely to enhance all of the properties of high sensitivity, reduced roughness, and suppressed occurrence of 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 structural unit (a6), or may be in both of these forms. The compounds exemplified below as the component (D1) may be used as the acid generator component (component (B)) in combination with other compounds.

[0387] Regarding component (D1) The component (D1) is not particularly limited as long as it decomposes upon exposure to light and loses its acid diffusion controllability, and is preferably one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)"). The components (d1-1) to (d1-3) do not act as quenchers in the exposed areas of the resist film because they decompose and lose their acid diffusion control properties (basicity), but act as quenchers in the unexposed areas of the resist film.

[0388] [ka] [In the formula, Rd 1 ~Rd 4is 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 this case, 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.

[0389] {(d1-1) component} Anion part In formula (d1-1), Rd 1 represents Rd in the above general formula (d1-an-1). 1 Preferable examples of the anion moiety of the component (d1-1) are the same as those given as preferred specific examples of the anion represented by the above general formula (d1-an-1).

[0390] Cation part In formula (d1-1), M m+ is an m-valent organic cation. M m+ Suitable organic cations include those similar to those represented by the general 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. The component (d1-1) may be used alone or in combination of two or more.

[0391] {(d1-2) component} Anion part In formula (d1-2), Rd 2 represents Rd in the above general formula (d1-an-2). 2 Preferable 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).

[0392] Cation part In formula (d1-2), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-2) may be used alone or in combination of two or more.

[0393] {(d1-3) component} Anion part In formula (d1-3), Rd 3 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and 201 The Rd is preferably a fluorine atom-containing cyclic group, a chain alkyl group, or a chain alkenyl group. Among these, a fluorinated alkyl group is preferred, and the Rd 1 The same fluorinated alkyl groups as those mentioned above are more preferred.

[0394] 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 R' 201 The same can be mentioned. Among these, alkyl groups, alkoxy groups, alkenyl groups and cyclic groups which may have a substituent are preferred. Road 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 portion of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, or the like. Road 4The 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.

[0395] Road 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.

[0396] Road 4 The cyclic group in the formula (I) is the same as the R' 201 Examples of the cyclic groups include cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclo[5.2.1.0 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.

[0397] In formula (d1-3), Yd 1 is a single bond or a divalent linking group. Yd 1 The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. 21Examples of the divalent linking group include the same divalent hydrocarbon groups which may have a substituent and divalent linking groups containing a hetero atom as those mentioned in the description of the divalent linking group in the above. Yd 1 is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0398] Preferred examples of the anion moiety of the component (d1-3) are shown below.

[0399] [ka]

[0400] [ka]

[0401] Cation part In formula (d1-3), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-3) may be used alone or in combination of two or more.

[0402] The component (D1) may be any one of the components (d1-1) to (d1-3) above, 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).

[0403] The component (D1) preferably contains the component (d1-1) above. The content of the component (d1-1) in the entire component (D1) is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The component (D1) may consist solely of the compound component (d1-1).

[0404] Manufacturing method of component (D1): The method for producing the components (d1-1) and (d1-2) is not particularly limited, and they can be produced by known methods. The method for producing component (d1-3) is not particularly limited, and it can be produced, for example, in a manner similar to that described in US2012-0149916. The compound of component (D1) has been shown as an example of a base component (component (D)) that traps acid generated by exposure, but the compound of component (D1) may also be used as component (B). For example, in the resist composition of this embodiment, a compound of component (D1) may be used as the 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 the component (D). Alternatively, in the resist composition of this embodiment, a compound of component (D1) may be used as the component (B), and a component (D2) described below may be used as the component (D).

[0405] Regarding component (D2) The component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the component (D1) above. The component (D2) is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of component (D1), and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are particularly preferred. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms. Examples of aliphatic amines include amines in which at least one hydrogen atom of ammonia NH3 has been substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcoholamines 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 alcoholamines 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.

[0406] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of the aliphatic monocyclic amine include piperidine and piperazine. The aliphatic polycyclic amine is preferably one having 6 to 10 carbon atoms, and specific examples thereof include 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0407] 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, and triethanolamine triacetate, with triethanolamine triacetate being preferred.

[0408] Furthermore, an aromatic amine may be used as the component (D2). Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, 2,6-di-tert-butylpyridine, and 2,6-di-tert-butylpyridine.

[0409] The component (D2) may be used alone or in combination of two or more. 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 this range, the resist pattern shape and stability over time during storage can be improved.

[0410] <<At least one compound (E) selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof>> The resist composition of this embodiment may contain, as an optional component, at least one compound (E) selected from the group consisting of organic carboxylic acids, and phosphorus oxo acids and derivatives thereof (hereafter referred to as "component (E)") for the purposes of preventing sensitivity degradation and improving the resist pattern shape and stability over time after exposure. Specific examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid, with salicylic acid being preferred. Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred.

[0411] In the resist composition of this embodiment, the component (E) may be used either as a single type, or in combination of two or more types. 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 setting the amount within this range, lithography properties are further improved.

[0412] <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. Component (F) is used to impart water repellency to the resist film, and when used as a resin separate from component (A), it can improve lithography properties. As the component (F), for example, the fluorine-containing polymer compounds described in JP-A Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569, and 2011-128226 can be used. More specifically, component (F) may be a polymer having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting solely 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), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1), 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.

[0413] [ka] [wherein R is the same as defined above, and Rf 102 and Rf 103 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Rf 102 and Rf 103 may be the same or different. 1 is an integer from 0 to 5, and Rf 101 is an organic group containing a fluorine atom.

[0414] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. In formula (f1-1), Rf 102 and Rf 103 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 Rf103 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 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 even more preferably a hydrogen atom. In formula (f1-1), nf 1 is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0415] In formula (f1-1), Rf 101 is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The fluorine atom-containing hydrocarbon group may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. Furthermore, in the fluorine atom-containing hydrocarbon group, preferably 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among them, Rf 101 is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a trifluoromethyl group, -CH2-CF3, -CH2-CF2-CF3, -CH(CF3)2, -CH2-CH2-CF3, or -CH2-CH2-CF2-CF2-CF2-CF3.

[0416] 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, and when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.0 to 2.5.

[0417] In the resist composition of this embodiment, the component (F) may be used alone, or in combination of two or more different compounds. When the resist composition contains the component (F), the amount of the component (F) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the component (A).

[0418] <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 types, with propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), γ-butyrolactone, ethyl lactate (EL), and cyclohexanone being preferred.

[0419] Furthermore, a mixed solvent of PGMEA and a polar solvent is also preferred as component (S), and the blending ratio (mass ratio) may be appropriately determined taking into consideration the compatibility between PGMEA and the polar solvent, etc. The component (S) is also preferably a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone, in which case the mass ratio of the former to the latter is preferably 70:30 to 95:5. There are no particular restrictions on the amount of component (S) used, and it is set appropriately depending on the coating film thickness so as to provide a concentration that allows application to a substrate, etc. Generally, the component (S) is used so that the solids concentration of the resist composition falls within the range of 0.1 to 20 mass %, and preferably 0.2 to 15 mass %.

[0420] 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 such polyimide porous films and polyamideimide porous films include those described in JP 2016-155121 A.

[0421] The resist composition of the present embodiment 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 the present 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 (terminal group (I-1)) represented by general formula (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) 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 properties of the resist film are improved, and the rigidity of the resist film is also increased, making it easier to improve the acid diffusion suppression effect. In addition, since 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 connected to the main chain, the solubility contrast in a developer between the exposed and unexposed areas of the resist film is increased. Furthermore, since 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 obtained due to the above-mentioned synergistic action.

[0422] (Method for forming a resist pattern) One embodiment of the method for forming a resist pattern is a method including the steps of forming a resist film on a support using the resist composition of the above-described embodiment, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. One embodiment of the resist pattern forming method is, for example, a resist pattern forming method carried out as follows.

[0423] First, the resist composition of the above-described embodiment is applied onto a support using a spinner or the like, and then baked (post-apply bake (PAB)) at a temperature of, for example, 80 to 150°C for 40 to 120 seconds, preferably 60 to 90 seconds, to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an ArF exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with an electron beam without using a mask pattern, and then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed using an alkaline developer in the case of an alkaline development process, or a developer containing an organic solvent (organic developer) in the case of a solvent development process.

[0424] After the development process, a rinse process is preferably carried out. In the case of an alkaline development process, the rinse process is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse solution containing an organic solvent is preferably used. In the case of a solvent development process, the developing or rinsing treatment may be followed by a treatment using a supercritical fluid to remove the developing solution or rinsing solution adhering to the pattern. After the development treatment or rinsing treatment, the film is dried. In some cases, a baking treatment (post-baking) may be performed after the development treatment.

[0425] 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.

[0426] The wavelength used for exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, and soft X-rays can be used. The method for 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.

[0427] The exposure method for the resist film may be a normal exposure (dry exposure) carried out in air or an inert gas such as nitrogen, or may be liquid immersion lithography. Immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure device is filled with a solvent (immersion medium) that has a refractive index greater than that of air, and then exposure (immersion exposure) is performed in that state. The immersion medium is preferably a solvent having a refractive index greater than that of air and less than that of the resist film to be exposed, such as water, a fluorine-based inert liquid, a silicon-based solvent, or a hydrocarbon-based solvent. As the immersion medium, water is preferably used.

[0428] The alkaline developer used in the development treatment in the alkaline development process may be, for example, a 0.1 to 10 mass % aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent capable of dissolving component (A) (component (A) before exposure), and may 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.

[0429] 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.

[0430] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0431] 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.

[0432] 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).

[0433] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be selected appropriately from the organic solvents listed above as organic solvents used in the organic developer, so long as it does 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 of two or more, and may be used in combination with other organic solvents or water.

[0434] 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).

[0435] 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.

[0436] 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 metal-containing impurities include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, and salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially free (below the detection limit of the measuring device).

[0437] (compound) One embodiment of the compound is a compound represented by the following general formula (I):

[0438] [ka] [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)-, -OC(=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 multiple R present in the formula 1 , multiple Z, multiple X, multiple R 2 may be the same or different. N is a nitrogen atom.

[0439] In the formula (I), R 1 , Z, X, R 2 is R in the above formula (I-1). 1 , Z, X, R 2 are the same as In addition, the plurality of R 1 , multiple Z, multiple X, multiple R 2 may be the same or different from each other, but are preferably the same from an industrial standpoint. The compound of this embodiment, that is, the compound represented by the above general formula (I), is the same as the above-mentioned compound (I).

[0440] [Method of manufacturing the compound] One embodiment of the method for producing a compound represented by general formula (I) (compound (I)) is a production method including 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)").

[0441] [ka] [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 1and 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.]

[0442] 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 standpoint. In the formula (I-02), R 2 represents R in the formula (I-1). 2 is the same as: In the 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 groups which may have a substituent and divalent linking groups containing a hetero atom as exemplified in the description of X in the formula (I-1) above.

[0443] 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 condensation reaction of compound (I-01) with compound (I-02) by a known synthesis method.

[0444] 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).

[0445] [ka] [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 ]

[0446] 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 the compound with thionyl chloride using a known synthesis method. Next, depending on the purpose, compound (I-05) is subjected to a condensation reaction with compound (I-04), which is a carboxylic acid, or compound (I-02), which is an alcohol, by a known synthesis method, to produce compound (I).

[0447] As the compound (I-01), the compound (I-03), the compound (I-02), and the compound (I-04), commercially available compounds or synthesized compounds may be used. After the reaction is complete, Compound (I) in the reaction mixture may be isolated and purified by a conventional method, such as concentration, solvent extraction, distillation, crystallization, recrystallization, or chromatography, either alone or in combination. The structure of compound (I) obtained as 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.

[0448] (Radical polymerization initiator) One embodiment of the radical polymerization initiator contains a compound represented by the above-mentioned general formula (I) (compound (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 the present 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 also 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.

[0449] 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. Preferred monomers to be polymerized using the radical polymerization initiator are acrylic ester monomers, vinyl monomers, or styrene monomers, with acrylic ester monomers being particularly preferred. Examples of acrylic ester monomers include monomers that derive the aforementioned structural units (a1), (a10), (a2), (a5), (a6), and (a8).

[0450] (polymer) One embodiment of the polymer is a polymer having a group (terminal group (I-1)) represented by the following general formula (I-1) at at least one end of the main chain. The polymer of this embodiment has an end group (I-1), and therefore also has an iodine atom at at least one end of the main chain of the polymer, which, when used in a resist composition, can achieve high sensitivity and improved lithography properties (roughness, exposure latitude, etc.) in resist pattern formation.

[0451] [ka] [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)-, -OC(=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.]

[0452] 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.

[0453] The polymer of the present embodiment may have an end group (I-1) at at least one end of the main chain, and other components (for example, structural units constituting the polymer) may be known ones depending on the intended use of the polymer. The polymer of this embodiment is useful for a resist composition. The polymer of this embodiment is particularly useful as a base component for a chemically amplified resist composition, or as an additive component that is optionally blended into such a resist composition. It is particularly preferred that the polymer be used as a base component for a chemically amplified resist composition. The structure of the polymer used as the base component is the same as that of the component (A1-0) described above.

[0454] Suitable examples of the polymer of this embodiment include radical polymers obtained by radical polymerization using a radical polymerization initiator containing the compound represented by the above-mentioned general formula (I). [Example]

[0455] 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 the present example, the compound represented by chemical formula (1) will be referred to as "compound (1)", and the same will be used for compounds represented by other chemical formulas.

[0456] <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, the mixture was crystallized using acetone and heptane to obtain compound (I-iii-11) (25.2 g, yield = 82.0%).

[0457] [ka]

[0458] [Synthesis of Compound (I-iii-12) and Compound (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 the aforementioned compound (I-iii-11), 4-iodophenol was replaced with the following phenols (PO-2, PO-3) in equimolar amounts.

[0459] [ka]

[0460] [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, followed by dropwise addition of thionyl chloride (7.1 g, 60.0 mmol) at 10°C or below. After stirring at room temperature for 3 hours, the mixture was washed three times with 100 g of 1% NH3 aqueous solution and four times with 100 g of ultrapure water. After distilling off the solvent, the mixture was dried under reduced pressure to obtain precursor (Pre-01) (13.0 g, yield = 80.0%).

[0461] [ka]

[0462] 4-Iodobenzoic acid (12.4 g, 50.0 mmol) was dissolved in 50 g of dimethylformamide (DMF). Potassium carbonate (10.4 g, 75.0 mmol) was added to the solution, followed by dropwise addition of 50 g of a DMF solution of precursor (Pre-01) (14.6 g, 45.0 mmol). 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, followed by washing three times with 200 g of ultrapure water. After distilling off the solvent, compound (I-iii-14) was obtained by crystallization using acetone, tetrahydrofuran (THF), and heptane (26.9 g, yield = 80.0%).

[0463] [ka]

[0464] [Synthesis of Compound (I-iii-15) and Compound (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 was replaced with the following carboxylic acids (CA1, CA2) in equimolar amounts.

[0465] [ka]

[0466] [Synthesis of Compounds (Ii-11) to (Ii-13)] A 300 mL three-neck flask was charged with 1,1'-carbonyldiimidazole (CDI) (4.60 g, 28.4 mmol) and acetonitrile (20 g). A solution of 3-hydroxy-4-iodobenzoic acid (6.7 g, 25.5 mmol) in acetonitrile (20 g) was then added dropwise over 30 minutes and allowed to react for 1 hour. Compound (K-1) (9.5 g, 30.6 mmol) was then added and 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. The precipitated solid was filtered. The filtered product was again dissolved in methanol (100 g) and added dropwise to MTBE (500 g). The precipitated solid was filtered. The filtered product was dried under reduced pressure to obtain intermediate 1 (7.3 g, yield = 70.1%).

[0467] [ka]

[0468] Intermediate 2 and Intermediate 3 were obtained in the same manner as in the synthesis of Intermediate 1, except that in the synthesis of Intermediate 1 described above, 3-hydroxy-4-iodobenzoic acid was replaced with the following carboxylic acids (CA3, CA4) in equimolar amounts, respectively.

[0469] [ka]

[0470] 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%).

[0471] [ka]

[0472] 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.

[0473] [ka]

[0474] Compounds (Ii-11), (Ii-12), and (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 4, 5, and 6, respectively.

[0475] [ka]

[0476] [Synthesis of compounds (Ii-14) to (Ii-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), 50 g of 2% aqueous sodium hydroxide solution was added, and 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 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%).

[0477] [ka]

[0478] 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 carboxylic acids (CA3, CA4) in equimolar amounts.

[0479] [ka]

[0480] Compounds (Ii-14), (Ii-15), and (Ii-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.

[0481] [ka]

[0482] [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%).

[0483] [ka]

[0484] Compound C was obtained in the same manner as in the synthesis of Compound B, 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, except that in the synthesis of compound B, diphenyl sulfoxide was changed to bis(4-iodophenyl) sulfoxide in equimolar amounts.

[0485] [ka]

[0486] Compound (L-1) (4.1 g, 10.0 mmol) and compound B (4.7 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 10 (6.1 g, yield = 92.0%).

[0487] [ka]

[0488] Intermediate 11 and Intermediate 12 were obtained in the same manner as in the synthesis of Intermediate 10, except that compound B was replaced with the above-mentioned compound C and compound D in equimolar amounts, respectively.

[0489] [ka]

[0490] 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.

[0491] [ka]

[0492] [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), 50 g of 2% aqueous sodium hydroxide solution was added, and 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 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%).

[0493] [ka]

[0494] 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 Compound C and Compound D in equimolar amounts, respectively.

[0495] [ka]

[0496] 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.

[0497] [ka]

[0498] NMR measurements were carried out on the obtained compounds (I-iii-11) to (I-iii-16), compounds (Ii-11) to (Ii-16), and compounds (I-ii-11) to (I-ii-16), and their structures were identified from the analytical results shown below.

[0499] 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)

[0500] 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)

[0501] 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)

[0502] Compound (I-iii-14): 1H-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)

[0503] Compound (I-iii-15): 1 H-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)

[0504] 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, CH2, 4H), 1.25(s, CH3, 12H)

[0505] Compound (Ii-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)

[0506] Compound (Ii-12): 1H-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)

[0507] Compound (Ii-13): 1 H-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, CH2CH2, 8H), 1.62-1.66(d, CH3, 6H)

[0508] Compound (Ii-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)

[0509] Compound (Ii-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)

[0510] Compound (Ii-16): 1H-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)

[0511] Compound (I-ii-11): 1 H-NMR(DMSO-d6,400MHz): 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)

[0512] Compound (I-ii-12): 1 H-NMR(DMSO-d6,400MHz): 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)

[0513] Compound (I-ii-13): 1H-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)

[0514] Compound (I-ii-14): 1 H-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)

[0515] 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)

[0516] Compound (I-ii-16): 1H-NMR (DMSO-d6,400MHz):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)

[0517] [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, 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 and aged for 1 hour. Ultrapure water (160.0 g) and dichloromethane (160.0 g) were then charged 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).

[0518] [ka]

[0519] 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).

[0520] [ka]

[0521] 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).

[0522] [ka]

[0523] The resulting compound (a5-2m) was subjected to NMR measurement, and its structure was identified from the analytical results shown below. 1 H-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).

[0524] <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. Then, 3.2 g of acetic acid and 60 g of methanol (MeOH) were added to the reaction solution, and the deprotection reaction was carried out at 30 °C for 18 hours. After the reaction was completed, 1200 g of a mixed solvent of methanol and water was added to the resulting reaction solution to precipitate and wash the precipitate. 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%).

[0525] [ka]

[0526] [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 preparation of the copolymer are listed below.

[0527] [ka]

[0528] [ka]

[0529] The resulting copolymers (A1-001) to (A1-030) are shown below. In the following chemical formula, l, m, n, and o represent the composition ratio (molar ratio) of each structural unit, and [ ] in the formula indicates the terminal structure of the polymer main chain.

[0530] [ka]

[0531] [ka]

[0532] [ka]

[0533] [ka]

[0534] [ka]

[0535] [ka]

[0536] [ka]

[0537] [ka]

[0538] [ka]

[0539] [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 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.

[0540] [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. Then, 4.2 g of acetic acid and 80 g of methanol (MeOH) were added to the reaction solution, and the deprotection reaction was carried out at 30 °C for 18 hours. After the reaction was completed, heptane (600 g) was added to the resulting reaction solution to precipitate and wash the precipitate. The resulting white solid was filtered and dried under reduced pressure overnight to obtain the target copolymer (A2-2).

[0541] [ka]

[0542] [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 that derive the structural units constituting the copolymer were mixed 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.

[0543] [ka]

[0544] The radical polymerization initiators and chain transfer agents used in the production of the copolymers (A2-1) to (A2-5) are shown below.

[0545] [ka]

[0546] The resulting copolymers (A2-1) to (A2-5) are shown below. In the following chemical formula, l, m, n, and o represent the composition ratio (molar ratio) of each structural unit, and [ ] in the formula indicates the terminal structure of the polymer main chain.

[0547] [ka]

[0548] 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 The results were determined by C-NMR. These results are shown in Tables 1 to 3 together with the radical polymerization initiators or chain transfer agents used.

[0549] [Table 1]

[0550] [Table 2]

[0551] [Table 3]

[0552] <Preparation of Resist Composition> (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.

[0553] [Table 4]

[0554] [Table 5]

[0555] [Table 6]

[0556] In Tables 4 to 6, the abbreviations have the following meanings: The numbers in brackets [ ] are the blend amounts (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).

[0557] (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).

[0558] [ka]

[0559] (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).

[0560] [ka]

[0561] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0562] <Formation of Resist Pattern> Steps for forming a resist film: Each resist composition of each example was applied using a spinner onto an 8-inch silicon substrate that had been treated with hexamethyldisilazane (HMDS), and then pre-baked (PAB) on a hot plate at 110°C for 60 seconds, followed by drying to form a resist film with a thickness of 50 nm.

[0563] Step of exposing the resist film: Next, the resist film was subjected to exposure (writing) using an electron beam lithography system JEOL-JBX-9300FS (manufactured by JEOL Ltd.) at an acceleration voltage of 100 kV to form a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a target size of 25 nm line width (50 nm pitch). Thereafter, post-exposure baking (PEB) was performed at 100° C. for 60 seconds.

[0564] A process for developing the exposed resist film: Next, alkaline development was carried out at 23° C. for 60 seconds using a 2.38 mass % tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, the substrate was rinsed with pure water for 15 seconds. As a result, a 1:1 LS pattern with a line width of 25 nm (pitch of 50 nm) was formed.

[0565] [Evaluation of optimal exposure (Eop)] The optimum exposure dose Eop (μC / cm) for forming a target size LS pattern by the above <Formation of resist pattern> 2 This is called "Eop (μC / cm 2 )" are shown in Tables 7 to 9.

[0566] [Evaluation of LWR (Line Width Roughness)] For the LS patterns formed in the above <Formation of Resist Pattern>, 3σ, which is a measure of LWR, was determined, and this is shown in Tables 7 to 9 as "LWR (nm)". The "3σ" indicates three times the standard deviation (σ) (3σ) (unit: nm) obtained from the measurement results of measuring 400 line positions 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 less rough the line sidewalls are, meaning that an LS pattern with a more uniform width is obtained.

[0567] [Evaluation of 5% EL margin] The exposure dose required to form a target size LS pattern, i.e., a 1:1 LS pattern with a line width of 25 nm (pitch of 50 nm) using the above <Resist Pattern Formation>, within a range of ±5% of the target dimensions was calculated, and the EL margin (unit: %) was calculated using the following formula. The results are shown in Tables 7 to 9 as "5% EL (%)."

[0568] EL margin (%) = (|E1-E2| / Eop) x 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 2 ) The larger the EL margin, the smaller the change in pattern size due to fluctuations in exposure dose, indicating a wider process margin.

[0569] [Evaluation of storage stability] The prepared resist compositions were divided into samples stored at refrigerated temperatures below 5°C and samples stored at high temperatures at 60°C. After storing the samples stored at each temperature for 48 hours, patterning was carried out according to the above <Formation of Resist Pattern>. For each sample, the optimum exposure dose Eop (μC / cm) at which an LS pattern of the target size was formed was determined. 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.

[0570] Variation rate (%) of optimal exposure amount = (optimal exposure amount of high-temperature stored sample) / (optimal exposure amount of refrigerated stored sample) Evaluation criteria A: The fluctuation rate of the optimum exposure dose is 0 to less than 3%, and the storage stability is good. B: The fluctuation rate of the optimum exposure dose is 3% or more, and the storage stability is poor.

[0571] [Table 7]

[0572] [Table 8]

[0573] [Table 9]

[0574] 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 improve both the effect of reducing roughness and the exposure latitude, and also had good storage stability.

Claims

1. A resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, Contains a resin component whose solubility in a developer changes under the action of acid, The resist composition includes a polymer in which the resin component has a group represented by the following general formula (I-1) at at least one end of the main chain: 【Chemical 1】 [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 is the ionic group (i), 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): 【Chemistry 2】 [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), 2. The resist composition according to claim 1, wherein the ionic group (ii) is an ionic group represented by the following general formula (ii-1): 【Chemistry 3】 [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 is the hydrocarbon group (iii), 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: a step of forming a resist film on a support using the resist composition according to any one of claims 1 to 4; a step of exposing the resist film; and a step of developing the exposed resist film to form a resist pattern.

6. A compound represented by the following general formula (I): 【Chemistry 4】 [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. 【Chemistry 5】 [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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