Resist composition, method for forming resist pattern, and copolymer

Abstract

The present invention employs a resist composition which contains a resin component that has a constituent unit derived from a compound represented by general formula (a01-b) and a constituent unit derived from a compound represented by general formula (a02-d). In the formulae, W01 and W02 each represent a group containing a polymerizable group. X01 and X02 each represent a divalent linking group or a single bond. R0 represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. Mm+ represents an m-valent onium cation. Nn+ represents an n-valent onium cation. Meanwhile, an iodine atom is contained in any one or more of X01, X02, Mm+, and Nn+. This resist composition makes it possible to enhance the sensitivity during the formation of a resist pattern, and to achieve improvement of the lithography characteristics such as reduction in roughness of a pattern, and also makes it possible to increase the process margin.

Description

Resist composition, method for forming resist pattern, and copolymer

[0001] This application claims priority to Japanese Patent Application No. 2023-097027, filed on June 13, 2023, the contents of which are incorporated herein by reference.

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

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

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

[0005] Furthermore, as a resist material, a chemically amplified resist composition has also been proposed which contains, in addition to an acid generator component, an acid diffusion controller that controls the diffusion of the acid generated from the acid generator component upon exposure.

[0006] JP 2014-197168 A

[0007] With the further progress of lithography technology and the expansion of application fields, pattern miniaturization is rapidly progressing. Accordingly, when manufacturing semiconductor devices and the like, a technology capable of forming fine-dimensional patterns with good shapes is required. Therefore, resist compositions are required to have even higher sensitivity and further improved lithography properties such as reduced pattern roughness. In addition, a wide process margin is also required, such as the effect on pattern size due to fluctuations in exposure dose. However, conventional resist compositions such as those described in Patent Document 1 require further improvement in terms of these required properties.

[0008] 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 improved lithography properties such as increased sensitivity and reduced pattern roughness when forming a resist pattern, while also providing a wide process margin; a method of forming a resist pattern that uses this resist composition; and a copolymer that is useful for this resist composition.

[0009] In order to solve the above problems, the present invention employs the following configuration. That is, a first aspect of the present invention is a resist composition that generates acid upon exposure, and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component (A1) whose solubility in a developer changes due to the action of the acid, the resin component (A1) having a structural unit (a01) derived from a compound represented by the following general formula (a01-b), and a structural unit (a02) derived from a compound represented by the following general formula (a02-d):

[0010] [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, and m is an integer of 1 or more. ０２is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0011] 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.

[0012] A third aspect of the present invention is a copolymer having a structural unit (a01) derived from a compound represented by the following general formula (a01-b), and a structural unit (a02) derived from a compound represented by the following general formula (a02-d):

[0013] [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, and m is an integer of 1 or more. ０２ is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0014] According to the present invention, it is possible to provide a resist composition that achieves improved lithography properties, such as increased sensitivity and reduced pattern roughness when forming a resist pattern, while also providing a wide process margin, a method of forming a resist pattern that uses this resist composition, and a copolymer that is useful for this resist composition.

[0015] In this specification and claims, "aliphatic" is a relative concept to aromatic, and is defined as meaning a group, compound, etc. that does not have aromaticity. "Alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups, unless otherwise specified. The same applies to alkyl groups in alkoxy groups. "Alkylene group" includes linear, branched, and cyclic divalent saturated hydrocarbon groups, unless otherwise specified. "Halogen atom" includes fluorine, chlorine, bromine, and iodine atoms. "Structural unit" means a monomer unit that constitutes a polymer compound (resin, polymer, copolymer). When describing "may have a substituent," it refers to cases where a hydrogen atom (-H) is replaced with a monovalent group, and cases where a methylene group (-CH ２ The term "exposure" encompasses both cases where the radical (-) is substituted with a divalent group.

[0016] An "acid-decomposable group" is a group having acid decomposability in which at least a part of the bond in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases by the action of an acid include groups that decompose by the action of an acid to generate a polar group. Examples of polar groups include a carboxy group, a hydroxyl group, an amino group, and a sulfo group (-SO ３ More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0017] The term "acid-dissociable group" refers to either (i) a group having acid dissociability in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a portion of the bond is cleaved by the action of an acid, followed by a decarboxylation reaction, in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Thus, when the acid-dissociable group is dissociated by the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, thereby increasing the polarity. As a result, the polarity of the entire component (A1) increases. The increase in polarity relatively changes the solubility in the developer, increasing the solubility when the developer is an alkaline developer and decreasing the solubility when the developer is an organic developer.

[0018] A "base component" is an organic compound that has film-forming ability. Organic compounds used as base components are broadly classified into non-polymers and polymers. As non-polymers, those with a molecular weight of 500 or more and less than 4000 are usually used (hereinafter referred to as "low molecular weight compounds"). Hereinafter, when referring to "resin," "high molecular weight compound," or "polymer," it refers to a polymer with a molecular weight of 1000 or more. The molecular weight of the polymer is the weight average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography).

[0019] The term "derived structural unit" refers to a structural unit formed by cleavage of a multiple bond between carbon atoms, for example, an ethylenic double bond. In the "acrylic acid ester", the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R αｘ ) is an atom or group other than a hydrogen atom. αｘ ) is substituted with a substituent containing an ester bond, or αｘThis also includes α-hydroxyacrylic esters in which the α-position carbon atom of an acrylic ester is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-position carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, acrylic esters in which the hydrogen atom bonded to the α-position carbon atom has been replaced with a substituent may be referred to as α-substituted acrylic esters.

[0020] The term "derivative" is used as a concept including compounds in which the hydrogen atom at the α-position of the target compound is substituted with other substituents such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of the hydroxyl group of a target compound in which the hydrogen atom at the α-position may be substituted with a substituent is substituted with an organic group; compounds in which a substituent other than a hydroxyl group is bonded to a target compound in which the hydrogen atom at the α-position may be substituted with a substituent; and the like. Unless otherwise specified, the α-position refers to the first carbon atom adjacent to the functional group. Examples of substituents that substitute the hydrogen atom at the α-position of hydroxystyrene include R αｘ Examples include alkyl groups, halogenated alkyl groups, and the like.

[0021] In this specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms, and may exist as enantiomers or diastereoisomers. In such cases, a single chemical formula represents all of the isomers. These isomers may be used alone or as a mixture.

[0022] (Resist Composition) The resist composition of this embodiment generates an acid upon exposure, and its solubility in a developer changes due to the action of the acid. This resist composition contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of the acid. In the resist composition of this embodiment, component (A) contains a resin component that generates an acid upon exposure, and whose solubility in a developer changes due to the action of the acid.

[0023]

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

[0024] The resist composition of this embodiment may be a positive resist composition or a negative resist composition. Furthermore, the resist composition of this embodiment may be for use in an alkaline development process in which an alkaline developer is used for the development treatment during resist pattern formation, or for use in a solvent development process in which a developer containing an organic solvent (organic developer) is used for the development treatment.

[0025] <Base Component (A)> In the resist composition of this embodiment, the component (A) contains a resin component (A1) (hereinafter also referred to as "component (A1)") whose solubility in a developer changes under the action of an acid. By using the component (A1), for example, the polarity of the base component changes before and after exposure, making it possible to obtain good development contrast not only in an alkaline development process but also in a solvent development process. As the component (A), at least one other polymeric compound and a low molecular weight compound may be used in combination with the component (A1). In the resist composition of this embodiment, one type of component (A) may be used alone, or two or more types may be used in combination.

[0026] Regarding Resin Component (A1): The component (A1) is a resin component whose solubility in a developer changes under the action of an acid. This component (A1) has a structural unit (a01) derived from a compound represented by general formula (a01-b) described below, and a structural unit (a02) derived from a compound represented by general formula (a02-d). In the structural unit (a01) and the structural unit (a02), X in the general formula ０１ , X ０２ , M ｍ＋ and N ｎ＋ At least one of the structural units (a01) and (a02) contains an iodine atom. Both of these structural units (a01) and (a02) generate acid upon exposure. In the resist composition, the structural unit (a02) traps the acid generated from the structural unit (a01) upon exposure (controls the diffusion of the acid). In addition to the structural unit (a01) and the structural unit (a02), the component (A1) may also contain other structural units as necessary.

[0027] <<Structural Unit (a01)>> The structural unit (a01) is a structural unit derived from a compound represented by the following general formula (a01-b): The structural unit (a01) is a structural unit that generates sulfonic acid upon exposure in exposed areas of the resist film.

[0028] [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. However, X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0029] {Anion moiety} In the formula (a01-b), W ０１With regard to the polymerizable group-containing group in (1), the "polymerizable group" refers to a group that enables a compound having a polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms such as an ethylenic double bond. Examples of the polymerizable group include a vinyl group, an α-methylvinyl group, an allyl group, an acryloyl group, a methacryloyl group, a fluorovinyl group, a difluorovinyl group, a trifluorovinyl group, a difluorotrifluoromethylvinyl group, a trifluoroallyl group, a perfluoroallyl group, a trifluoromethylacryloyl group, a nonylfluorobutylacryloyl group, a vinyl ether group, a fluorine-containing vinyl ether group, an allyl ether group, a fluorine-containing allyl ether group, a styryl group, a vinylnaphthyl group, a fluorine-containing styryl group, a fluorine-containing vinylnaphthyl group, a norbornyl group, a fluorine-containing norbornyl group, a silyl group, and a maleimide group.

[0030] The polymerizable group-containing group may be a group composed of only a polymerizable group, or may be a group composed of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Examples of the polymerizable group-containing group include a group represented by the formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０ In the above formula, R Ｘ１１ , R Ｘ１２ and R Ｘ１３ each independently represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom; ｘ０ represents a divalent linking group or a single bond.

[0031] R Ｘ１１ , R Ｘ１２ and R Ｘ１３The alkyl group having 1 to 5 carbon atoms in the formula (I) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferred. R Ｘ１１ , R Ｘ１２ and R Ｘ１３ 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. Ｘ１１ and R Ｘ１２ is particularly preferably a hydrogen atom, and R Ｘ１３ is particularly preferably a hydrogen atom or a methyl group.

[0032] Ya ｘ０ Examples of the divalent linking group in the above formula include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ｘ０ The divalent linking group in the formula (a01-b) described later is X ０１ Examples of the divalent linking group include the same as those exemplified in the description of the divalent linking group in the above, and preferred examples include an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an ether bond (-O-), a linear or branched alkylene group, an arylene group which may have a substituent, or any combination thereof.

[0033] In the formula (a01-b), X ０１ In the formula (I), examples of the divalent linking group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0034] A divalent hydrocarbon group which may have a substituent: X ０１ The optionally substituted divalent hydrocarbon group in the formula (I) may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0035] Aliphatic hydrocarbon group: An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated (for example, an alkenylene group, an alkynylene group, etc.). Examples of the aliphatic hydrocarbon group include a chain aliphatic hydrocarbon group and an aliphatic hydrocarbon group containing a ring in its structure. The chain aliphatic hydrocarbon group may be a straight-chain aliphatic hydrocarbon group or a branched-chain aliphatic hydrocarbon group.

[0036] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched chain aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched chain aliphatic hydrocarbon group, a branched chain alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0037] The linear or branched aliphatic hydrocarbon group may or may not have a substituent.

[0038] ...Aliphatic hydrocarbon groups containing a ring in their structure. Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopropane, cyclopentane, and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0039] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxy group, and a carbonyl group. Some of the carbon atoms constituting the ring structure of the cyclic aliphatic hydrocarbon group may be substituted with a substituent containing a heteroatom. Examples of the substituent containing a heteroatom include -O-, -C(=O)-O-, -S-, and -S(=O) ２ -, -S(=O) ２ —O— is preferred.

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

[0041] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxy group.

[0042] Divalent linking group containing a hetero atom: X０１ In the formula (I), examples of the divalent linking group containing a hetero atom include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as a hydrocarbon group, an acyl group or an alkoxyalkyl group), -S-, -S(=O) ２ -, -S(=O) ２ -O-, general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O) ２ -O-Y ２２ -, wherein Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m" is an integer of 1 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as a hydrocarbon group, an acyl group, or an alkoxyalkyl group. The substituent preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms.

[0043] General formula-Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O)２ -O-Y ２２ -Middle, Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as those described above. ２１ and Y ２２ Each of Y is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group. ２１ and Y ２２ As each of the groups, a linear or branched aliphatic hydrocarbon group or a linear or branched fluorinated aliphatic hydrocarbon group is preferable, and a linear or branched alkylene group having 1 to 5 carbon atoms or a linear or branched fluorinated alkylene group is more preferable.

[0044] X ０１ is preferably a cyclic aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), an amide bond [-NH-C(=O)-, -C(=O)-NH-], a linear or branched aliphatic hydrocarbon group, a linear or branched fluorinated aliphatic hydrocarbon group, or a combination of two or more thereof, or one which contains a single bond; and more preferably a cyclic aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an ester bond [-C(=O)-O-, -O-C(=O)-], a linear or branched aliphatic hydrocarbon group, a linear or branched fluorinated aliphatic hydrocarbon group, or a combination of two or more thereof.

[0045] In the structural units (a01) and (a02), X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ At least one of X in the formula (a01-b) contains an iodine atom. ０１When iodine atoms are contained, the number of iodine atoms may be, for example, 1 to 4, 1 to 3, 2, or 1. The greater the number of iodine atoms, the easier it is to achieve high sensitivity. In addition, the effect of the iodine atoms reduces pattern bridging in regions with low exposure doses and reduces pattern collapse in regions with high exposure doses, making it easier to expand the process margin.

[0046] In the formula (a01-b), R ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, preferably a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom, and more preferably a fluorine atom.

[0047] Suitable examples of the structural unit (a01) include structural units represented by the following general formula (a01-b0):

[0048] [wherein R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０１ represents a divalent linking group containing a hetero atom or a single bond. ０１ represents an aromatic hydrocarbon group which may have a substituent, or an alicyclic hydrocarbon group which may have a substituent. ０１ represents a divalent linking group or a single bond. ０１ represents a fluorinated alkylene group, an alkylene group, or a single bond. ０１ and Va ０１ and R cannot both be single bonds. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0049] In the formula (a01-b0), the alkyl group having 1 to 5 carbon atoms for R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms for R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. A fluorine atom is preferred as the halogen atom. In terms of industrial availability, a hydrogen atom or a methyl group is preferred as R.

[0050] In the formula (a01-b0), Yx ０１ In the above, examples of the divalent linking group containing a hetero atom include the above-mentioned Ya ｘ０ Examples of the divalent linking group include the same as the divalent linking group containing a hetero atom exemplified in the description of the divalent linking group in ０１ Specific examples of the alkylene group include an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an ether bond (-O-), a linear or branched alkylene group, an arylene group which may have a substituent, any combination thereof, or a single bond. A combination of an arylene group which may have a substituent and an ester bond (-C(=O)-O-), an ester bond (-C(=O)-O-), or a single bond is preferred, and a combination of a phenylene group which may have a substituent and an ester bond (-C(=O)-O-), or an ester bond (-C(=O)-O-).

[0051] In the formula (a01-b0), La ０１ represents an aromatic hydrocarbon group which may have a substituent, or an alicyclic hydrocarbon group which may have a substituent. ０１ As the above, X ０１ Examples of the divalent hydrocarbon group that may have a substituent include the aromatic hydrocarbon group and the cyclic aliphatic hydrocarbon group exemplified in the description of the divalent hydrocarbon group that may have a substituent in La. ０１The aromatic hydrocarbon group in is preferably a group in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring or an aromatic heterocycle (an arylene group or a heteroarylene group), more preferably an arylene group, and even more preferably a phenylene group. ０１ The alicyclic hydrocarbon group in may be a monocyclic alicyclic hydrocarbon group or a polycyclic alicyclic hydrocarbon group, preferably a polycyclic alicyclic hydrocarbon group, more preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and even more preferably a group in which two hydrogen atoms have been removed from adamantane. ０１ The substituent that the aromatic hydrocarbon group or alicyclic hydrocarbon group may have in the above is preferably a halogen atom, and more preferably an iodine atom from the viewpoint of increasing sensitivity when forming a resist pattern. The number of iodine atoms as the substituent may be, for example, 1 to 4, 1 to 3, 2, or 1. The greater the number of iodine atoms as the substituent, the easier it is to achieve high sensitivity. In addition, the effect of the iodine atoms reduces pattern bridging in regions with low exposure doses and reduces pattern collapse in regions with high exposure doses, making it easier to expand the process margin. Among the above, La ０１ is preferably an aromatic hydrocarbon group which may have a substituent.

[0052] In the formula (a01-b0), Ya ０１ represents a divalent linking group or a single bond. ０１ The divalent linking group in ０１ Examples of the divalent linking group containing a hetero atom include those similar to those in the above formula. ０１ is preferably an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—), or an oxycarbonyl group (—O—C(═O)—), and (La ０１ side) -C(=O)-O-(Va ０１ It is more preferable that the side is the side.

[0053] In the formula (a01-b0), Va ０１ represents a fluorinated alkylene group, an alkylene group, or a single bond. ０１ The alkylene group in the formula (I) is the same as that in the formula (I). ０１Examples of the linear or branched aliphatic hydrocarbon group include those similar to those in the above formula. ０１ As the fluorinated alkylene group in ０１ In the above formula, some or all of the hydrogen atoms constituting the alkylene group are substituted with fluorine atoms. ０１ is a methylene group (-CH ２ -), -CH(CF ３ )- is preferred.

[0054] In the formula (a01-b0), R ０ represents a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom, preferably a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom, and more preferably a fluorine atom.

[0055] Specific examples of the structural unit (a01) include, but are not limited to, the following: α represents a trifluoromethyl group, a methyl group, or a hydrogen atom. ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more.

[0056]

[0057] The structural unit (a01) is preferably a structural unit represented by any one of the aforementioned formulas (a01-b01), (a01-b02), (a01-b03), and (a01-b04), and more preferably a structural unit represented by any one of the aforementioned formulas (a01-b01) and (a01-b03).

[0058] {Cation moiety} In the above formula (a01-b) and formula (a01-b0), M ｍ＋ is an m-valent onium cation, where m is an integer of 1 or more. ｍ＋ Among the onium cations in the formula (M), sulfonium cation and iodonium cation are more preferred. ｍ＋ ) １／ｍ Examples of the onium cation include those represented by the following general formulas (ca-1) to (ca-3).

[0059] [In the formula, R ２０１~R ２０７ R each independently represents an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. ２０１ ~R ２０３ , R ２０６ ~R ２０７ may be bonded to each other to form a ring together with the sulfur atom in the formula. ２０８ ~R ２０９ R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２０１ represents —C(═O)— or —C(═O)—O—.]

[0060] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０７ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２０１ ~R ２０７ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２０１ ~R ２０７ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２０１ ~R ２０７ , and R ２１０ Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulas (car-r-1) to (car-r-8), respectively. Among these, an alkyl group, a halogen atom, a halogenated alkyl group, and groups represented by the following general formulas (car-r-1) to (car-r-8), respectively, are preferred, and a chain alkyl group, an iodine atom, a fluorine atom, a fluorinated alkyl group, and a group represented by the following general formula (car-r-3), respectively, are more preferred.

[0061] [In the formula, R' ２０１are each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0062] Cyclic group which may have a substituent: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group which does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0063] R' ２０１ The aromatic hydrocarbon group in R' is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. ２０１ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R' include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. ２０１ Specific examples of the aromatic hydrocarbon group in the formula (I) include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0064] R' ２０１Examples of the cyclic aliphatic hydrocarbon group in the formula (I) include aliphatic hydrocarbon groups containing a ring within their structure. Examples of aliphatic hydrocarbon groups containing a ring within their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed within a linear or branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be either a polycyclic group or a monocyclic group. Preferred monocyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a monocycloalkane. Preferred monocycloalkanes have 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. Preferred polycyclic alicyclic hydrocarbon groups are groups in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a polycyclic skeleton of a bridged ring system, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a polycyclic skeleton of a fused ring system, such as a cyclic group having a steroid skeleton.

[0065] 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.

[0066] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ )２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specifically, —CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0067] Also, R' ２０１ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, —SO 4 groups represented by the general formulae (b5-r-1) to (b5-r-4) described below, ２ -containing cyclic groups, and heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16).

[0068]

[0069] R' ２０１ Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. The halogen atom as a substituent is preferably a fluorine atom or an iodine atom. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH ２ -) is a group that substitutes

[0070] A chain alkyl group which may have a substituent: R' ２０１The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0071] A chain alkenyl group which may have a substituent: R' ２０１ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of linear alkenyl groups include a vinyl group, a propenyl group (allyl group), and a butenyl group. Examples of branched alkenyl groups include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the above chain alkenyl groups, linear alkenyl groups are preferred, with a vinyl group and a propenyl group being more preferred, and a vinyl group being particularly preferred.

[0072] 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:

[0073] R' ２０１In addition to the above-mentioned optionally substituted cyclic groups, optionally substituted chain alkyl groups, and optionally substituted chain alkenyl groups, examples of the optionally substituted cyclic groups or optionally substituted chain alkyl groups include those similar to the acid-dissociable groups represented by formula (a1-r-2) described below.

[0074] Among them, R' ２０１ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane; a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7) described below; -SO represented by each of the general formulae (b5-r-1) to (b5-r-4) described below; ２ For example, from the viewpoint of achieving high sensitivity when forming a resist pattern, an aromatic hydrocarbon group which may have a substituent is preferred, an aromatic hydrocarbon group having an iodine atom bonded as a substituent is more preferred, and a benzene ring having an iodine atom bonded as a substituent is particularly preferred.

[0075] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０３ , R ２０６ ~R ２０７ When they are bonded to each other to form a ring together with the sulfur atom in the formula, they are not substituted with heteroatoms such as sulfur atoms, oxygen atoms, and nitrogen atoms, or with carbonyl groups, -SO-, -SO ２ -, -SO ３ -, -COO-, -CONH- or -N(R Ｎ )-(the R Ｎis an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0076] 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.

[0077] R ２１０ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an —SO ２ -containing cyclic group. ２１０ The aryl group in R is an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. ２１０ The alkyl group in R is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. ２１０ The alkenyl group in R preferably has 2 to 10 carbon atoms. ２１０ In the -SO ２ The -containing cyclic group is not particularly limited and any group can be used. Specific examples include groups represented by the following general formulae (b5-r-1) to (b5-r-4), and "-SO ２ -containing polycyclic group" is preferred, and a group represented by general formula (b5-r-1) is more preferred.

[0078] [In the formula, Rb' ５１are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, or —SO ２ -containing cyclic group; B" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; n' is an integer of 0 to 2; * represents a bond.

[0079] 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.

[0080] 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.

[0081] Specific examples of the groups represented by general formulae (b5-r-1) to (b5-r-4) are listed below, where "Ac" represents an acetyl group.

[0082]

[0083]

[0084]

[0085] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas.

[0086]

[0087]

[0088] [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.]

[0089]

[0090]

[0091] [In the formula, R” ２０１ is a hydrogen atom or a substituent, and the substituent is the same as R ２０１ ~R ２０７ , and R ２１０ ~R ２１２ The substituents are the same as those exemplified as the substituents that may be possessed by

[0092]

[0093]

[0094] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0095] 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).

[0096]

[0097] The cation moiety ((M ｍ＋ ) １／ｍ) are more preferably cations represented by the formulas (ca-1) to (ca-3), and the cations represented by the formulas (ca-1-1) to (ca-1-87); diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation are particularly preferred. Among these, the cation represented by the formula (ca-1) is preferred, and particularly from the viewpoint of increasing sensitivity, suitable cations represented by the formula (ca-1) are preferably those having an electron-withdrawing group such as a fluorine atom, a fluorinated alkyl group, or a sulfonyl group; or an iodine atom as a substituent, and for example, cations selected from the group consisting of the cations represented by the above chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84), and (ca-1-85) to (ca-1-87) are particularly preferred. The number of iodine atoms as a substituent may be, for example, 1 to 4, 1 to 3, 2, or 1. The more iodine atoms there are as substituents, the easier it is to achieve high sensitivity. In addition, the effect of iodine atoms is to reduce pattern bridging in areas with low exposure doses and pattern collapse in areas with high exposure doses, which makes it easier to expand the process margin.

[0098] Specific examples of the structural unit (a01) include, but are not limited to, the following: α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0099]

[0100]

[0101]

[0102] The structural unit (a01) is preferably a structural unit represented by any one of the above formulas (a01-b11) to (a01-b13), (a01-b21) to (a01-b24), (a01-b31) to (a01-b33), and (a01-b41), and is more preferably a structural unit represented by any one of the above formulas (a01-b31) to (a01-b33).

[0103] The structural unit (a01) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a01) in the component (A1), relative to the total (100 mol%) of all structural units constituting the component (A1), is preferably 1 to 40 mol%, more preferably 2 to 30 mol%, even more preferably 5 to 25 mol%, and particularly preferably 10 to 20 mol%. When the proportion of the structural unit (a01) is at least the lower limit of the above-mentioned preferred range, sensitivity during resist pattern formation is further improved, and lithography properties such as reduced pattern roughness are also likely to be improved. When the proportion of the structural unit (a01) is at most the upper limit of the above-mentioned preferred range, it is easier to achieve a balance with the other structural units.

[0104] <<Structural Unit (a02)>> The structural unit (a02) is a structural unit derived from a compound represented by the following general formula (a02-d): The structural unit (a02) generates carboxylic acid upon exposure in the exposed areas of the resist film, and also functions as a quencher (acid diffusion controller) that traps the acid generated from the structural unit (a01) upon exposure in the unexposed areas of the resist film.

[0105] [In formula (a02-d), W ０２ is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. However, X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0106] {Anion moiety} In the formula (a02-d), W ０２ The polymerizable group-containing group in the formula (a01-b) is W ０１ The same applies to the polymerizable group-containing group in W. ０２ Examples of the polymerizable group-containing group in the formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０In the above formula, R Ｘ１１ , R Ｘ１２ and R Ｘ１３ each independently represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom; ｘ０ represents a divalent linking group or a single bond. Ｘ１１ , R Ｘ１２ and R Ｘ１３ 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. Ｘ１１ and R Ｘ１２ is particularly preferably a hydrogen atom, and R Ｘ１３ is particularly preferably a hydrogen atom or a methyl group. ｘ０ Examples of the alkyl group include a single bond, an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an ether bond (-O-), a linear or branched alkylene group, an arylene group which may have a substituent, and any combination thereof.

[0107] In the formula (a02-d), X ０２ In the formula, examples of the divalent linking group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ０２ The divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in the above formula (a01-b) are ０１ The explanations for the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in X are the same as those for the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom. ０２is preferably a cyclic aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), an amide bond [-NH-C(=O)-, -C(=O)-NH-], a linear or branched aliphatic hydrocarbon group, or a combination of two or more thereof, or one which contains a single bond; and more preferably an aromatic hydrocarbon group which may have a substituent, an ether bond (-O-), a linear or branched aliphatic hydrocarbon group, or a combination of two or more thereof.

[0108] In the structural units (a01) and (a02), X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ At least one of X in the formula (a02-d) contains an iodine atom. ０２ When iodine atoms are contained, the number of iodine atoms may be, for example, 1 to 4, 1 to 3, 2, or 1. The greater the number of iodine atoms, the easier it is to achieve high sensitivity. In addition, the effect of the iodine atoms reduces pattern bridging in regions with low exposure doses and reduces pattern collapse in regions with high exposure doses, making it easier to expand the process margin.

[0109] Suitable examples of the structural unit (a02) include structural units represented by general formula (a02-d0) shown below.

[0110] [wherein R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ０２ represents a divalent linking group containing a hetero atom or a single bond. ０２ represents an aromatic hydrocarbon group which may have a substituent. ０２ represents a divalent linking group or a single bond. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. However, X in formula (a01-b) and formula (a02-d0) ０１ , Ar ０２ , M ｍ＋ and Nｎ＋ Any one or more of the groups contains an iodine atom.]

[0111] In the formula (a02-d0), R is the same as that in the formula (a01-b0). In view of industrial availability, R is preferably a hydrogen atom or a methyl group.

[0112] In the formula (a02-d0), Yx ０２ is Yx in the formula (a01-b0). ０１ The same as the explanation for Yx ０２ Specific examples of include an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an ether bond (-O-), a linear or branched alkylene group, an arylene group which may have a substituent, any combination thereof, or a single bond, and a combination of an arylene group which may have a substituent, a linear or branched alkylene group, and an ether bond (-O-), an ester bond (-C(=O)-O-), or a single bond is preferred.

[0113] In the formula (a02-d0), Ar ０２ is La in the formula (a01-b0). ０１ The same applies to the aromatic hydrocarbon group which may have a substituent as described above. ０２ The aromatic hydrocarbon group in Ar is preferably a group in which two hydrogen atoms have been removed from an aromatic hydrocarbon ring or an aromatic heterocycle (an arylene group or a heteroarylene group), more preferably an arylene group, and even more preferably a phenylene group. ０２In the above, the substituent that the aromatic hydrocarbon group may have is preferably a halogen atom or a hydroxy group. From the viewpoint of increasing sensitivity when forming a resist pattern, a halogen atom is more preferred, and an iodine atom is even more preferred. The number of iodine atoms as the substituent may be, for example, 1 to 4, 1 to 3, 2, or 1. The greater the number of iodine atoms as the substituent, the easier it is to achieve high sensitivity. In addition, due to the effect of the iodine atoms, pattern bridging is reduced in regions with low exposure dose, and pattern collapse is reduced in regions with high exposure dose, making it easier to widen the process margin. Furthermore, Ar ０２ In terms of solubility in a developer, the substituent that the aromatic hydrocarbon group may have is preferably a hydroxy group. The number of hydroxy groups as the substituent may be, for example, two or one.

[0114] In the formula (a02-d0), Ya ０２ In the formula (a01-b), the divalent linking group is X ０１ Examples of the divalent linking group containing a hetero atom include those similar to those in the above formula. ０２ represents an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), a linear or branched alkylene group, any combination thereof, or a single bond, and (Ar ０２ side) -O-linear or branched alkylene group -COO － , or a single bond, and (Ar ０２ Side) -O-CH ２ -COO － or a single bond is more preferred.

[0115] Specific examples of the structural unit (a02) include, but are not limited to, the following: α represents a trifluoromethyl group, a methyl group, or a hydrogen atom. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more.

[0116]

[0117] The structural unit (a02) is preferably a structural unit represented by any one of the above formulas (a02-d01), (a02-d02), (a02-d03), (a02-d04), (a02-d05), and (a02-d06), and more preferably a structural unit represented by any one of the above formulas (a02-d02), (a02-d04), and (a02-d05).

[0118] {Cation moiety} In the above formula (a02-d) and formula (a02-d0), N ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. ｎ＋ Among the onium cations in the formula (I), sulfonium cation and iodonium cation are more preferred. ｎ＋ ) １／ｎ Examples of the cation include the onium cations represented by the general formulas (ca-1) to (ca-3) above, and among these, the cations represented by the formulas (ca-1-1) to (ca-1-87) above are more preferred; diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation are more preferred. Among these, the cation represented by the formula (ca-1) is preferred, and particularly from the viewpoint of increasing sensitivity, the preferred cation represented by the formula (ca-1) is preferably one having an electron-withdrawing group such as a fluorine atom, a fluorinated alkyl group, or a sulfonyl group, or an iodine atom as a substituent, and for example, a cation selected from the group consisting of the cations represented by the chemical formulas (ca-1-44), (ca-1-71) to (ca-1-84), and (ca-1-85) to (ca-1-87) above are particularly preferred. The number of iodine atoms as a substituent may be, for example, 1 to 4, 1 to 3, 2, or 1. The more iodine atoms there are as substituents, the easier it is to achieve high sensitivity. In addition, the effect of iodine atoms is to reduce pattern bridging in areas with low exposure doses and pattern collapse in areas with high exposure doses, which makes it easier to expand the process margin.

[0119] Specific examples of the structural unit (a02) include, but are not limited to, the following: α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0120]

[0121] The structural unit (a02) is preferably a structural unit represented by any one of the above formulas (a02-d11) to (a02-d13), (a02-d21), (a02-d31), (a02-d41), (a02-d51), and (a02-d61), and more preferably a structural unit represented by any one of the above formulas (a02-d12), (a02-d21), (a02-d41), and (a02-d51).

[0122] The structural unit (a02) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a02) in the component (A1), relative to the total (100 mol%) of all structural units constituting the component (A1), is preferably 0.5 to 20 mol%, more preferably 1 to 15 mol%, even more preferably 1 to 10 mol%, and particularly preferably 2 to 8 mol%. When the proportion of the structural unit (a02) is at least the lower limit of the above-mentioned preferred range, improvements in lithography properties such as reduced pattern roughness are more likely to be achieved. When the proportion of the structural unit (a02) is at most the upper limit of the above-mentioned preferred range, it is easier to achieve a balance with the other structural units.

[0123] <<Other Structural Units>> The component (A1) may contain other structural units, as necessary, in addition to the structural units (a01) and (a02) described above. Examples of other structural units include a structural unit (a1) containing an acid-decomposable group that becomes more polar when acted upon by an acid, a structural unit (a10) represented by general formula (a10-1) described below, a structural unit (a2) containing a lactone-containing cyclic group, and a structural unit (a8) derived from a compound represented by general formula (a8-1) described below.

[0124] Structural unit (a1): The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity increases under the action of acid. Examples of acid-dissociable groups constituting the acid-decomposable group include those that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions. Examples of acid-dissociable groups that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions include "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," "tertiary alkyloxycarbonyl acid-dissociable groups," and "secondary alkyl ester-type acid-dissociable groups."

[0125] Acetal-Type Acid-Dissociable Group: Among the polar groups, examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter, sometimes referred to as "acetal-type acid-dissociable group"):

[0126] [In the formula, Ra' １ , Ra' ２ is a hydrogen atom or an alkyl group. ３ is a hydrocarbon group, and Ra' ３ is Ra' １ , Ra' ２ may be bonded to any one of the following to form a ring.]

[0127] In formula (a1-r-1), Ra' １ and Ra' ２ Among Ra', at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. １ or Ra' ２ When is an alkyl group, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester above, and alkyl groups having 1 to 5 carbon atoms are preferred. Specific examples include linear or branched alkyl groups. More specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. A methyl group or an ethyl group is more preferred, and a methyl group is particularly preferred.

[0128] 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.

[0129] 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.

[0130] Ra' ３ When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. As an alicyclic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an alicyclic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0131] Ra' ３When the cyclic hydrocarbon group described above becomes an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Ra' ３ Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (an aryl group or a heteroaryl group); a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0132] Ra' ３ The cyclic hydrocarbon group in may have a substituent. Examples of the substituent include -R Ｐ１ , -R Ｐ２ -O-R Ｐ１ , -R Ｐ２ -CO-R Ｐ１ , -R Ｐ２ -CO-OR Ｐ１ , -R Ｐ２ -O-CO-R Ｐ１ , -R Ｐ２ -OH, -R Ｐ２ -CN or -RＰ２ -COOH (hereinafter, these substituents are collectively referred to as "Ra ｘ５ ") etc. Here, R Ｐ１ is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ２ is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ１ and R Ｐ２ Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the alicyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic hydrocarbon group may have one or more of one type of the above-mentioned substituents, or may have one or more of each of two or more types of the above-mentioned substituents. Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, and cyclododecyl; and polycyclic aliphatic saturated hydrocarbon groups such as bicyclo[2.2.2]octanyl, tricyclo[5.2.1.02,6]decanyl, tricyclo[3.3.1.13,7]decanyl, tetracyclo[6.2.1.13,6.02,7]dodecanyl, and adamantyl. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene.

[0133] Ra' ３ But Ra' １ , Ra' ２When the cyclic group is bonded to any one of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0134] Tertiary alkyl ester acid-dissociable group: Among the above polar groups, examples of the acid-dissociable group protecting the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2): Of the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group will hereinafter be referred to as "tertiary alkyl ester acid-dissociable groups" for convenience.

[0135] [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.

[0136] Ra' ４ Examples of the hydrocarbon group of Ra' include a linear or branched alkyl group, a linear or cyclic alkenyl group, a linear alkynyl group, and a cyclic hydrocarbon group. ４ The linear or branched alkyl group and the cyclic hydrocarbon group (the alicyclic hydrocarbon group which is a monocyclic group, the alicyclic hydrocarbon group which is a polycyclic group, and the aromatic hydrocarbon group) in ３ The same as Ra' can be mentioned. ４ The chain or cyclic alkenyl group in Ra' is preferably an alkenyl group having 2 to 10 carbon atoms. ５ , Ra' ６ The hydrocarbon group of Ra' ３ The same can be mentioned.

[0137] Ra' ５ and Ra' ６ When Ra' is bonded to each other to form a ring, preferred examples thereof include a group represented by the following general formula (a1-r2-1), a group represented by the following general formula (a1-r2-2), and a group represented by the following general formula (a1-r2-3). ４ ~Ra' ６When the groups are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0138] [In formula (a1-r2-1), Ra' １０ represents a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. １１ is Ra' １０ represents a group which forms an aliphatic cyclic group together with the carbon atom to which it is bonded. In formula (a1-r2-2), Ya is a carbon atom. Xa is a group which forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Ra １０１ ~Ra １０３ are each independently a hydrogen atom, a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent cyclic aliphatic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms in the linear saturated hydrocarbon group and the cyclic aliphatic saturated hydrocarbon group may be substituted. １０１ ~Ra １０３ Two or more of the above may be bonded to each other to form a cyclic structure. In formula (a1-r2-3), Yaa is a carbon atom. Xaa is a group that forms an aliphatic cyclic group together with Yaa. Ra １０４ In formula (a1-r2-4), Ra′ is an aromatic hydrocarbon group which may have a substituent. １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms of this chain saturated hydrocarbon group may be substituted. １４ is a hydrocarbon group which may have a substituent. * indicates a bond (the same applies hereinafter).

[0139] 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.

[0140] Ra' １０The linear alkyl group in Ra' has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. １０ In the formula (I), the branched alkyl group is the above-mentioned Ra' ３ The same can be mentioned.

[0141] Ra' １０ In the above, the alkyl group may be partially substituted with a halogen atom or a heteroatom-containing group. For example, some of the hydrogen atoms constituting the alkyl group may be substituted with a halogen atom or a heteroatom-containing group. Furthermore, some of the carbon atoms (such as methylene groups) constituting the alkyl group may be substituted with a heteroatom-containing group. Examples of the heteroatom include an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the heteroatom-containing group include (-O-), -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -S-, and -S(=O) ２ -, -S(=O) ２ -O- and the like.

[0142] In formula (a1-r2-1), Ra' １１ (Ra' １０ The aliphatic cyclic group formed together with the carbon atom to which Ra' is bonded in formula (a1-r-1) is ３ Among these, monocyclic alicyclic hydrocarbon groups are preferred, and specifically, cyclopentyl and cyclohexyl groups are more preferred.

[0143] In the formula (a1-r2-2), the cyclic hydrocarbon group formed by Xa together with Ya includes Ra' in the formula (a1-r-1). ３ Examples of the cyclic hydrocarbon group include a group in which one or more hydrogen atoms have been further removed from a cyclic monovalent hydrocarbon group (alicyclic hydrocarbon group) in the formula: ３ In formula (a1-r2-2), the substituents that the cyclic hydrocarbon group in formula (a1-r2-2) may have are the same as those in formula (a1-r2-2). １０１ ~Ra１０３ In the formula, examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. １０１ ~Ra １０３ In the formula (I), examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group; and polycyclic aliphatic saturated hydrocarbon groups such as a bicyclo[2.2.2]octanyl group, a tricyclo[5.2.1.02,6]decanyl group, a tricyclo[3.3.1.13,7]decanyl group, a tetracyclo[6.2.1.13,6.02,7]dodecanyl group, and an adamantyl group. １０１ ~Ra １０３ Among these, from the viewpoint of ease of synthesis, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferable, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferable, and a hydrogen atom is particularly preferable.

[0144] The above Ra １０１ ~Ra １０３ Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula (I) include the above-mentioned Ra ｘ５ The same groups as those shown below can be mentioned.

[0145] 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.

[0146] In formula (a1-r2-3), the aliphatic cyclic group formed by Xaa together with Yaa is Ra' in formula (a1-r-1). ３In formula (a1-r2-3), the groups exemplified as the alicyclic hydrocarbon group are preferably monocyclic or polycyclic groups. １０４ Examples of the aromatic hydrocarbon group in the formula (I) include a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 5 to 30 carbon atoms. 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.

[0147] Ra in formula (a1-r2-3) １０４ Examples of the substituent that may be possessed by the group include a methyl group, an ethyl group, a propyl group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group (e.g., a methoxy group, an ethoxy group, a propoxy group, a butoxy group), an alkyloxycarbonyl group, and the like.

[0148] In formula (a1-r2-4), Ra' １２ and Ra' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. １２ and Ra' １３ In the formula (I), the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Ra １０１ ~Ra １０３ The monovalent saturated chain hydrocarbon group having 1 to 10 carbon atoms in the formula (1) may be substituted in part or in whole. １２ and Ra' １３ Among these, Ra' is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group. １２ and Ra' １３ In the case where the chain saturated hydrocarbon group represented by the formula: ｘ５The same groups as those shown below can be mentioned.

[0149] In formula (a1-r2-4), Ra' １４ 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.

[0150] Ra' １４ The linear alkyl group in the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0151] Ra' １４ The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, and more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0152] Ra' １４ When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. As an alicyclic hydrocarbon group that is a monocyclic group, a group in which one hydrogen atom has been removed from a monocycloalkane is preferred. As the monocycloalkane, one having 3 to 6 carbon atoms is preferred, and specific examples thereof include cyclopentane and cyclohexane. As an alicyclic hydrocarbon group that is a polycyclic group, a group in which one hydrogen atom has been removed from a polycycloalkane is preferred, and as the polycycloalkane, one having 7 to 12 carbon atoms is preferred, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.

[0153] Ra' １４ As the aromatic hydrocarbon group in １０４Among them, the aromatic hydrocarbon groups Ra' are the same as those in １４ 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 naphthalene or anthracene, and most preferably a group in which one or more hydrogen atoms have been removed from naphthalene. １４ Examples of the substituent that may be possessed by Ra include １０４ Examples of the substituents include the same as those that may be possessed by the group.

[0154] Ra' in formula (a1-r2-4) １４ When Ra' in formula (a1-r2-4) is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. １４ When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be any one of the 1st, 2nd, and 9th positions of the anthryl group.

[0155] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0156]

[0157]

[0158]

[0159] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0160]

[0161]

[0162]

[0163] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0164]

[0165] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0166]

[0167] Tertiary alkyloxycarbonyl acid dissociable group: Examples of the acid dissociable group that protects the hydroxyl group of the polar group include acid dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience, may be referred to as "tertiary alkyloxycarbonyl acid dissociable group").

[0168] [In the formula, Ra' ７ ~Ra' ９ are each an alkyl group.

[0169] In formula (a1-r-3), Ra' ７ ~Ra' ９ are each preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. The total number of carbon atoms in each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

[0170] Secondary Alkyl Ester-Type Acid-Dissociable Group: Among the above polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-4).

[0171] [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.

[0172] In the formula, Ra'１０ and Ra' １２ The hydrocarbon group in Ra' is ３ In the formula, Ra' １１ａ and Ra' １１ｂ The alkyl group in Ra' is １ In the formula, Ra' is the same as the alkyl group in １０ and Ra' １２ and the hydrocarbon group in Ra' １１ａ and Ra' １１ｂ The alkyl group in may have a substituent. Examples of the substituent include the above-mentioned Ra ｘ５ etc.

[0173] Ra' １０ and Ra' １１ａ or Ra' １１ｂ may be bonded to each other to form a ring. The ring may be polycyclic or monocyclic, and may be an alicyclic or aromatic ring. The alicyclic and aromatic rings may contain heteroatoms.

[0174] Ra' １０ and Ra' １１ａ or Ra' １１ｂ and are bonded to each other to form a ring, among the above, a monocycloalkene, a ring in which a portion of the carbon atoms of a monocycloalkene is substituted with a heteroatom (such as an oxygen atom or a sulfur atom), or a monocycloalkadiene is preferred, a cycloalkene having 3 to 6 carbon atoms is preferred, and cyclopentene or cyclohexene is preferred.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] Specific examples of the group represented by the formula (a1-r-4) are listed below.

[0179]

[0180] 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.

[0181] Of the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Preferred specific examples of such a structural unit (a1) include structural units represented by the following general formula (a1-1), general formula (a1-2), or general formula (a1-3).

[0182] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １ is a divalent hydrocarbon group which may have an ether bond. ａ１ is an integer from 0 to 2. １ is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). １ is n ａ２+ is a monovalent hydrocarbon group. ａ２ is an integer from 1 to 3. ２ represents an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3). ００１ represents a single bond or a divalent linking group. ０１ is a single bond or a divalent linking group. ０１ is an acid-dissociable group represented by the above general formula (a1-r-1), (a1-r-2) or (a1-r-4). ０１ is an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group; q is an integer of 0 to 3; and n is an integer of 0 or greater, provided that n≦q×2+4.

[0183] In the formulas (a1-1) to (a1-3), the alkyl group having 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. A fluorine atom is particularly preferred as the halogen atom. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the perspective of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0184] In the formula (a1-1), Va １ The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0185] Va １ The aliphatic hydrocarbon group as the divalent hydrocarbon group in may be saturated or unsaturated, and is usually preferably saturated. More specific examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0186] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0187] Examples of the aliphatic hydrocarbon group containing a ring in its structure include alicyclic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same as the linear aliphatic hydrocarbon group or the branched aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. A preferred monocyclic alicyclic hydrocarbon group is a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0188] Va １The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such an aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (an arylene group); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (an aryl group) has been substituted with an alkylene group (for example, a group in which one further hydrogen atom has been removed from the aryl group of an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0189] 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.

[0190] In the formula (a1-2), Wa １ n in ａ２The +1-valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in the structure, and groups combining linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in the structure. ａ２ The +1 valence is preferably 2 to 4, more preferably 2 or 3. ２ is preferably an acid-dissociable group represented by the above general formula (a1-r-1).

[0191] In the formula (a1-3), Ya ００１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ００１ is preferably an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Among these, Ya ００１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0192] In the formula (a1-3), Ya ０１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ０１Among the above, it is preferable that Ya is an ester bond [—C(═O)—O—, —O—C(═O)—], an ether bond (—O—), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. ０１ The alkyl group is preferably a combination of an ester bond [—C(═O)—O—, —O—C(═O)—] and a linear alkylene group, or a single bond, and more preferably a single bond.

[0193] 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.

[0194] In the formula (a1-3), Rz ０１ The alkyl group, halogenated alkyl group, and alkoxy group in Rz preferably have 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, even more preferably 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms. The alkyl group, halogenated alkyl group, and alkoxy group may be linear or branched. ０１ The halogen atom in Rz is preferably an iodine atom or a bromine atom. ０１ The halogen atom of the halogenated alkyl group in Rz is preferably a fluorine atom, an iodine atom, or a bromine atom, and more preferably a fluorine atom. ０１ As the alkyl group, an alkoxy group or a hydroxy group is preferred, and a hydroxy group is more preferred.

[0195] In the formula (a1-3), q is an integer of 0 to 3. When q is 0, the structure is a benzene structure, when q is 1, the structure is a naphthalene structure, when q is 2, the structure is an anthracene structure, and when q is 3, the structure is a tetracene structure. In the formula (a1-3), n is an integer of 0 or more, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, and even more preferably 1 or 2. When n is an integer of 2 or more, two or more Rz ０１may be the same or different. In the formula (a1-3), n≦q×2+4. For example, when q is 1 and the naphthalene structure is formed, all six hydrogen atoms of the naphthalene are Rz ０１ In addition, in the naphthalene, Ya ００１ , -Ya ０１ -C(=O)-O-Rax ０１ group, and Rz ０１ The substitution position of is not particularly limited.

[0196] Specific examples of the structural unit (a1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. Each Rz independently represents a hydrogen atom, an alkyl group, a halogen atom, a halogenated alkyl group, a hydroxy group, or an alkoxy group.

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203]

[0204]

[0205]

[0206]

[0207]

[0208]

[0209]

[0210]

[0211] The structural unit (a1) contained in the component (A1) may be of one type, or may be of two or more types. As the structural unit (a1), a structural unit represented by the above formula (a1-1) or a structural unit represented by the above formula (a1-3) is more preferred, as these tend to further improve the properties (sensitivity, shape, etc.) in lithography using electron beams or EUV. Among these, an acid-dissociable group (Ra １ , Rax ０１ ) are preferably acid-dissociable groups represented by the following 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 a cyclic group.

[0212] [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.]

[0213] In the formula (a1-1-1), R, Va １ and n ａ１ represents R, Va in the formula (a1-1). １ and n ａ１ The acid-dissociable group represented by general formula (a1-r2-1), (a1-r2-3), (a1-r2-4), or (a1-r-4) has been described above. Among these, it is preferable to select an acid-dissociable group that is a cyclic group, as this is suitable for use with EB or EUV and can enhance reactivity.

[0214] The proportion of the structural unit (a1) in the component (A1) is preferably 20 to 75 mol%, more preferably 25 to 70 mol%, even more preferably 40 to 60 mol%, and particularly preferably 45 to 55 mol%, based on the total (100 mol%) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a1) is at least the lower limit of the above-mentioned preferred range, it becomes easier to achieve high sensitivity and etching resistance, and it also becomes easier to improve roughness and exposure latitude. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0215] Regarding the structural unit (a10): The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0216] In formula (a10-1), R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ｘ１ is a divalent linking group or a single bond. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ represents an integer of 1 or greater, as far as valence allows.

[0217] In the formula (a10-1), R is the same as R in the general formula (a1-1). R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom, a methyl group, or a trifluoromethyl group is more preferable, a hydrogen atom or a methyl group is still more preferable, and a hydrogen atom is particularly preferable.

[0218] In the formula (a10-1), Ya ｘ１ is a single bond or a divalent linking group. ｘ１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0219] Divalent hydrocarbon group which may have a substituent: The divalent hydrocarbon group which may have a substituent may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0220] Aliphatic hydrocarbon group: An aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups that contain a ring in their structure.

[0221] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched chain aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched chain aliphatic hydrocarbon group, a branched chain alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0222] 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.

[0223] ...Aliphatic hydrocarbon groups containing a ring in their structure. Examples of aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) that may contain a heteroatom-containing substituent in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0224] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and even more preferably a methoxy group or an ethoxy group. The halogen atom as the substituent is preferably a fluorine atom. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0225] Aromatic Hydrocarbon Group The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0226] In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include those exemplified as the substituent substituting a hydrogen atom of the cyclic aliphatic hydrocarbon group.

[0227] Divalent linking group containing a hetero atom: Examples of the divalent linking group containing a hetero atom include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, and -S(=O). ２ -, -S(=O) ２ -O-, general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O) ２ -O-Y ２２ -, wherein Y ２１ and Y ２２are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m" is an integer of 1 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. In the general formula -Y ２１ -O-Y ２２ -, -Y ２１ -O-, -Y ２１ -C(=O)-O-, -C(=O)-O-Y ２１ -, -[Y ２１ -C(=O)-O] ｍ” -Y ２２ -, -Y ２１ -OC(=O)-Y ２２ - or -Y ２１ -S(=O) ２ -O-Y ２２ -Middle, Y ２１ and Y ２２ are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as those described above. ２１ As Y, a linear aliphatic hydrocarbon group is preferred, a linear alkylene group is more preferred, a linear alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or an ethylene group is particularly preferred. ２２ is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. ２１ -C(=O)-O] ｍ” -Y ２２ In the group represented by -, m" is an integer of 1 to 3, preferably 1 or 2, and more preferably 1. That is, the group represented by the formula -[Y ２１ -C(=O)-O] ｍ”-Y ２２ The group represented by - includes the group represented by the formula -Y ２１ -C(=O)-O-Y ２２ Among them, groups represented by the formula -(CH ２ ) ａ’ -C(=O)-O-(CH ２ ) ｂ’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0228] Ya ｘ１ is preferably a single bond, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -O-C(=O)-].

[0229] In the formula (a10-1), Wa ｘ１ is an aromatic hydrocarbon group which may have a substituent. ｘ１ The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ａｘ１ Examples of the aromatic ring include a group in which 4n+1) hydrogen atoms have been removed. The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Wa ｘ１The aromatic hydrocarbon group in (n) is selected from aromatic compounds containing an aromatic ring which may have two or more substituents (for example, biphenyl, fluorene, etc.). ａｘ１ Also included are groups in which one or more hydrogen atoms have been removed. ｘ１ Examples of the aryl group include benzene, naphthalene, anthracene, and biphenyl (n ａｘ１ A group in which (n +1) hydrogen atoms have been removed is preferred, and a group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ａｘ１ A group in which (n +1) hydrogen atoms have been removed from benzene is more preferred, ａｘ１ A group in which 1) hydrogen atoms have been removed is more preferred.

[0230] Wa ｘ１ The aromatic hydrocarbon group in may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl group. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include Ya ｘ１ Examples of the substituent include the same as those exemplified as the substituent of the cyclic alicyclic hydrocarbon group in (1). The substituent is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, further preferably an ethyl group or a methyl group, and particularly preferably a methyl group. ｘ１ The aromatic hydrocarbon group in the formula (I) preferably does not have a substituent.

[0231] In the formula (a10-1), n ａｘ１ is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0232] Specific examples of the structural unit (a10) represented by the formula (a10-1) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0233]

[0234]

[0235]

[0236] The structural unit (a10) that the component (A1) can have may be one type, or two or more types. The component (A1) may or may not have the structural unit (a10), but preferably has the structural unit (a10). When the component (A1) has the structural unit (a10), the proportion of the structural unit (a10) in the component (A1) is preferably 10 to 60 mol%, more preferably 10 to 50 mol%, even more preferably 15 to 40 mol%, and particularly preferably 25 to 35 mol%, based on the total (100 mol%) of all structural units that make up the component (A1). By ensuring that the proportion of the structural unit (a10) is at or above the lower limit, sensitivity is likely to be further improved. On the other hand, by ensuring that the proportion is at or below the upper limit, it is easier to achieve a balance with other structural units.

[0237] Regarding the structural unit (a2): The component (A1) may further include a structural unit (a2) (excluding those corresponding to the structural unit (a1)) that includes a lactone-containing cyclic group. When the component (A1) is used to form a resist film, the lactone-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate. Furthermore, the presence of the structural unit (a2) provides effects such as appropriate adjustment of the acid diffusion length, improved adhesion of the resist film to the substrate, and appropriate adjustment of solubility during development, resulting in improved lithography properties.

[0238] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) that contains -O-C(=O)- within its ring skeleton. The lactone ring is counted as the first ring, and when there is only a lactone ring, it is called a monocyclic group, and when there is also another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. There are no particular restrictions on the lactone-containing cyclic group in the structural unit (a2), and any group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0239] [In the formula, Ra' ２１are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, or a lactone-containing cyclic group; A″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), an oxygen atom, or a sulfur atom; n′ is an integer of 0 to 2, and m′ is 0 or 1. * represents a bond (the same applies hereinafter).

[0240] In the general formulas (a2-r-1) to (a2-r-7), Ra' ２１ The alkyl group in Ra' is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Of these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' ２１ The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, ２１ Examples of the alkyl groups include those mentioned as examples of the alkyl group in the above formula and an oxygen atom (—O—). ２１ The halogen atom in Ra' is preferably a fluorine atom. ２１ As the halogenated alkyl group in the formula Ra′, ２１ Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0241] Ra' ２１In -COOR" and -OC(=O)R" in the formula (I), R" is either a hydrogen atom, an alkyl group, or a lactone-containing cyclic group. The alkyl group for R" may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R" is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably has 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably has 4 to 12 carbon atoms, and most preferably has 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specifically, examples of the lactone-containing cyclic group include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples of the lactone-containing cyclic group for R" include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7). Ra' ２１ The hydroxyalkyl group in the formula (Ra') preferably has 1 to 6 carbon atoms. ２１ and a group in which at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0242] Ra' ２１ Among the above, each of the groups is preferably independently a hydrogen atom or a cyano group.

[0243] In the general formulae (a2-r-2), (a2-r-3), and (a2-r-5), the alkylene group having 1 to 5 carbon atoms for A" is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include groups in which -O- or -S- is present at the terminal or between carbon atoms of the alkylene group, such as -O-CH ２ -, -CH ２ -O-CH ２ -, -S-CH ２ -, -CH ２ -S-CH ２ A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

[0244] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are listed below.

[0245]

[0246]

[0247] Of the structural units (a2), structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent are preferred. Such structural units (a2) are preferably structural units represented by the following general formula (a2-1):

[0248] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１ represents a single bond or a divalent linking group. ２１ represents -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. ２１ When is -O-, Ya ２１ does not become -CO-. ２１ is a lactone-containing cyclic group.

[0249] 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.

[0250] In the formula (a2-1), Ya ２１ The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. ２１ As the divalent linking group in the general formula (a10-1), ｘ１ Examples of the divalent linking group include the same as the divalent linking group in the above formula.

[0251] 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.

[0252] In the formula (a2-1), Ya ２１ is a single bond, and La ２１ is preferably —COO— or —OCO—.

[0253] In the formula (a2-1), Ra ２１ is a lactone-containing cyclic group. ２１ Suitable examples of the lactone-containing cyclic group in the formula (a2-r-1) include the groups represented by the general formulae (a2-r-1) to (a2-r-7) described above.

[0254] The component (A1) may contain one type of structural unit (a2), or two or more types. The component (A1) may or may not contain the structural unit (a2). When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 5 to 15 mol %, relative to the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a2) is at least the preferred lower limit, the aforementioned effects achieved by including the structural unit (a2) can be fully obtained. When the proportion is at or below the upper limit, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0255] Regarding the structural unit (a8): The structural unit (a8) is a structural unit derived from a compound represented by the following general formula (a8-1).

[0256] [In the formula, W ２ is a polymerizable group-containing group. ｘ２ is a single bond or (n ａｘ２ +1)valent linking group. ｘ２ and W ２ may form a condensed ring. １ is a fluorinated alkyl group having 1 to 12 carbon atoms. ２ R is a hydrogen atom or an organic group having 1 to 12 carbon atoms which may have a fluorine atom. ２ and Ya ｘ２ may be bonded to each other to form a ring structure. ａｘ２ is an integer from 1 to 3.

[0257] In the formula (a8-1), W ２ The polymerizable group-containing group in the formula (a01-b) is W ０１ The same applies to the polymerizable group-containing group in W. ２ Examples of the polymerizable group-containing group in the formula: C(R Ｘ１１ ) (R Ｘ１２ ) = C(R Ｘ１３ ) -Ya ｘ０ In this chemical formula, RＸ１１ , 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.

[0258] Ya ｘ２ and W ２ The fused ring formed by ２ The polymerizable group at the site and Ya ｘ２ and a fused ring formed by W ２ Other groups than the polymerizable group at the Ya ｘ２ and a fused ring formed by ｘ２ and W ２ The fused ring formed by these may have a substituent.

[0259] Specific examples of the structural unit (a8) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0260]

[0261] Among the above examples, the structural unit (a8) is preferably at least one type 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 type selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), and (a8-1-09).

[0262] The component (A1) may have one type of structural unit (a8), or two or more types. The component (A1) may or may not have the structural unit (a8). When the component (A1) has the structural unit (a8), the proportion of the structural unit (a8) in the component (A1) is preferably 30 mol % or less, more preferably 0 to 20 mol %, and even more preferably 0 to 10 mol %, relative to the total (100 mol %) of all structural units constituting the component (A1).

[0263] The resist composition contains, as a base component, the component (A1), either a single type of compound, or a combination of two or more types of compounds.

[0264] In the resist composition of this embodiment, the component (A1) is a resin component that contains the aforementioned structural unit (a01) and structural unit (a02), and preferably contains a copolymer that contains the aforementioned structural unit (a01) and structural unit (a02), more preferably contains a copolymer that contains the aforementioned structural unit (a01), structural unit (a02), structural unit (a1), and structural unit (a10), and particularly preferably contains a copolymer that is composed of the aforementioned structural unit (a01), structural unit (a02), structural unit (a1), and structural unit (a10).

[0265] In a copolymer having the structural unit (a01), the structural unit (a02), the structural unit (a1), and the structural unit (a10), the proportion of the structural unit (a01) is preferably 2 to 30 mol%, more preferably 5 to 25 mol%, and even more preferably 10 to 20 mol%, relative to the total (100 mol%) of all structural units constituting the copolymer; the proportion of the structural unit (a02) is preferably 1 to 15 mol%, more preferably 1 to 10 mol%, and even more preferably 2 to 8 mol%, relative to the total (100 mol%) of all structural units constituting the copolymer; the proportion of the structural unit (a1) is preferably 25 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 copolymer; The proportion of the structural unit (a10) relative to the total (100 mol%) of all structural units constituting the copolymer is preferably 10 to 50 mol%, more preferably 15 to 40 mol%, and even more preferably 25 to 35 mol%, provided that the total proportion of the structural unit (a01), the structural unit (a02), the structural unit (a1), and the structural unit (a10) does not exceed 100 mol%.

[0266] The total proportion of the structural unit (a01) and the structural unit (a02) relative to the total (100 mol%) of all structural units constituting the copolymer is preferably within a range from 3 to 45 mol%, more preferably from 6 to 35 mol%, and even more preferably from 12 to 28 mol%.

[0267] In the structural unit (a01) and the structural unit (a02), X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ At least one of the structural units (a01) and (a02) contains an iodine atom. The greater the number of iodine atoms, the easier it is to achieve high sensitivity. In addition, the effect of the iodine atoms reduces pattern bridging in regions with low exposure doses and reduces pattern collapse in regions with high exposure doses, making it easier to expand the process margin. The total number of iodine atoms in the structural units (a01) and (a02) is preferably 2 or more, more preferably 3 or more, and particularly preferably 4 to 5. Furthermore, X in formula (a01-b) and formula (a02-d) ０１ , X ０２ , M ｍ＋ and N ｎ＋ Of these, M ｍ＋ Preferably, an iodine atom is contained in

[0268] The ratio of the structural unit (a01) to the structural unit (a02), expressed as the molar ratio structural unit (a01) / structural unit (a02), is preferably from 60 / 40 to 90 / 10, more preferably from 65 / 35 to 85 / 15, and even more preferably from 70 / 30 to 80 / 20. When this molar ratio is at least the lower limit of the aforementioned preferred range, sensitivity when forming a resist pattern is further improved. On the other hand, when it is at most the upper limit of the aforementioned preferred range, lithography properties such as reduced pattern roughness are further improved.

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

[0270] Regarding the component (A2): The resist composition of this embodiment may also use, as the component (A), a base component (A2) (hereafter referred to as "component (A2)") that does not fall under the category of the component (A1) and whose solubility in a developer changes under the action of acid. There are no particular limitations on the component (A2), and it may be arbitrarily selected from the many base components conventionally known for use in chemically amplified resist compositions. The component (A2) may be a polymeric compound or a low molecular weight compound, and may be used either alone or in combination of two or more types.

[0271] The proportion of the component (A1) within the component (A), relative to the total weight of the component (A), is preferably 25% by weight or more, more preferably 50% by weight or more, and even more preferably 75% by weight or more, and may even be 100% by weight. When this proportion is 25% by weight or more, a resist pattern that exhibits excellent lithography properties such as high sensitivity, resolution, and reduced roughness is more easily formed, and the process margin also tends to be wider.

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

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

[0274] <Acid Generator Component (B)> The resist composition of this embodiment may further contain an acid generator component (B) (component (B)) that generates an acid upon exposure. There are no particular limitations on the component (B), and any of the components that have been proposed as acid generators for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl- or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators. The component (B) may be contained in the form of a compound, or may be incorporated into a base component in addition to the structural unit (a01) described above as a structural unit that generates an acid upon exposure, or may take both of these forms.

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

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

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

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

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

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

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

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

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

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

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

[0286]

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0305] {Cation Moiety} In the formula (b-1), formula (b-2), and formula (b-3), M' ｍ＋ represents an m-valent onium cation. ｍ＋ represents m and M in the general formula (a01-b). ｍ＋ Among these, sulfonium cations and iodonium cations are preferred. m is an integer of 1 or more.

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

[0307] In the resist composition of this embodiment, the component (B) may be used alone, or two or more types may be used in combination. In the resist composition, the amount of the component (B) relative to 100 parts by mass of the component (A1) is preferably less than 50 parts by mass, more preferably 0 to 40 parts by mass, even more preferably 0 to 30 parts by mass, and even more preferably 0 to 20 parts by mass. By ensuring that the amount of the component (B) falls within the above-mentioned preferred range, sufficient pattern formation is achieved. Furthermore, this is preferable because when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is improved.

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

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

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

[0311] {Component (d1-1)} Anion portion In formula (d1-1), Rd １ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of the R' ２０１ Among these, Rd １ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5). Note that Rd １ In the above general formulas (y-al-1) to (y-al-7), when the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group has, as a substituent, a linking group represented by each of the general formulae (y-al-1) to (y-al-7), Rd in formula (d1-1) １ The carbon atom constituting the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group in the formula (y-al-1) to (y-al-7) is bonded to V' １０１Suitable 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). More preferred examples of the aliphatic cyclic group include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; and branched alkyl groups such as 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, and 4-methylpentyl groups.

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

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

[0314]

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

[0316] {Component (d1-2)} Anion portion In formula (d1-2), Rd 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 ２０１ However, Rd ２ In the formula, the carbon atom adjacent to the S atom is not bonded to a fluorine atom (is not substituted with fluorine). This makes the anion of component (d1-2) an appropriately weak acid anion, improving the quenching ability of component (D). ２ is preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10 carbon atoms. The aliphatic cyclic group is more preferably a group (which may have a substituent) in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.; or a group in which one or more hydrogen atoms have been removed from camphor, etc. ２ The hydrocarbon group may have a substituent, and the substituent may be Rd １ Examples of the substituents include the same as those that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above.

[0317] Specific examples of preferred anion moieties of component (d1-2) are shown below.

[0318]

[0319] In formula (d1-2), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋ The component (d1-2) may be used alone or in combination of two or more.

[0320] {Component (d1-3)} Anion portion In formula (d1-3), Rd ３is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, a fluorinated alkyl group is preferred, and the Rd １ The same fluorinated alkyl groups as those mentioned above are more preferred.

[0321] In formula (d1-3), Rd ４ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ Among these, an alkyl group, an alkoxy group, an alkenyl group, or a cyclic group, which may have a substituent, is preferable. ４ The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. ４ A part of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, etc. ４ The alkoxy group in is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

[0322] Rd ４ The alkenyl group in R' ２０１ Examples include the same alkenyl groups as those in the above, and vinyl, propenyl (allyl), 1-methylpropenyl, and 2-methylpropenyl groups are preferred. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

[0323] Rd ４ The cyclic group in the formula (I) is the same as the R' ２０１Examples of the cyclic groups include those similar to the cyclic groups in the above, and preferred are alicyclic groups obtained by removing one or more hydrogen atoms from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane, or aromatic groups such as a phenyl group or a naphthyl group. ４ When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, 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.

[0324] In formula (d1-3), Yd １ represents a single bond or a divalent linking group. １ The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. ２１ Examples of the divalent linking group include the same divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom as those mentioned in the description of the divalent linking group in １ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0325] Specific examples of preferred anion moieties of component (d1-3) are shown below.

[0326]

[0327]

[0328] In formula (d1-3), M ｍ＋ is an m-valent organic cation, and M in the formula (d1-1) ｍ＋ The component (d1-3) may be used alone or in combination of two or more.

[0329] The component (D1) may be any one of the above components (d1-1) to (d1-3), or a combination of two or more of them. When the resist composition contains the component (D1), the amount of the component (D1) in the resist composition is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass, per 100 parts by mass of the component (A1). When the amount of the component (D1) is at least as large as the preferred lower limit, particularly favorable lithography properties and resist pattern shape are more likely to be obtained. On the other hand, when the amount is no more than the upper limit, good sensitivity can be maintained and excellent throughput can also be achieved.

[0330] Production method of component (D1): The production methods of the components (d1-1) and (d1-2) are not particularly limited, and they can be produced by known methods. The production method of component (d1-3) is also not particularly limited, and it can be produced, for example, by the method described in US 2012-0149916.

[0331] Regarding the (D2) component The (D) component may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the above-mentioned (D1) component. The (D2) component is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of the (D1) component, and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are more preferred. The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms. Examples of the aliphatic amine include ammonia NH ３Examples of the amine include amines in which at least one hydrogen atom is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 6 to 30 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0332] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of aliphatic monocyclic amines include piperidine and piperazine. Specific examples of aliphatic polycyclic amines include those having 6 to 10 carbon atoms, such as 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0333] Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, triethanolamine triacetate, and the like, with triethanolamine triacetate being preferred.

[0334] Furthermore, the component (D2) may be an aromatic amine, such as 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole, or a derivative thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, or 2,6-di-tert-butylpyridine.

[0335] The component (D2) may be used singly, or in combination of two or more types. When the resist composition contains the component (D2), the amount of the component (D2) within the resist composition is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A1). By ensuring that the amount is within this range, the resist pattern shape and stability over time during storage can be improved.

[0336] <<At least one compound (E) selected from the group consisting of organic carboxylic acids, phosphorus oxo acids, and derivatives thereof>> The resist composition of this embodiment may contain at least one compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxo acids, and derivatives thereof as an optional component for the purposes of preventing sensitivity degradation and improving resist pattern shape and post-exposure stability. Specific examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid, with salicylic acid being preferred. Examples of phosphorus oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Examples of derivatives of phosphorus oxo acids include esters in which the hydrogen atoms of the above oxo acids are substituted with hydrocarbon groups, with examples of the hydrocarbon groups being alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Examples of phosphoric acid derivatives include phosphate esters such as di-n-butyl phosphate and diphenyl phosphate. Examples of phosphonic acid derivatives include phosphonate esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Examples of phosphinic acid derivatives include phosphinic acid esters and phenylphosphinic acid. In the resist composition of this embodiment, the component (E) may be used alone or in combination with two or more different compounds. When the resist composition contains the component (E), the amount of the component (E) is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the component (A1). By using the component (E) in the above range, sensitivity, lithography properties, and the like are improved.

[0337] <Fluorine Additive Component (F)> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as "component (F)") as a hydrophobic resin. The component (F) is used to impart water repellency to the resist film, and by using it as a resin separate from the component (A), it is possible to improve lithography properties. As the component (F), for example, the fluorine-containing polymer compounds described in JP 2010-002870 A, JP 2010-032994 A, JP 2010-277043 A, JP 2011-13569 A, and JP 2011-128226 A can be used. More specific examples of the component (F) include polymers having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting only of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1), and more preferably a copolymer of the structural unit (f1) with the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate, and more preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate.

[0338] [wherein R is the same as defined above, and Rf １０２ and Rf １０３ Rf each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; １０２ and Rf １０３ may be the same or different. １ is an integer of 0 to 5, and Rf １０１ is an organic group containing a fluorine atom.

[0339] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. １０２ and Rf １０３ The halogen atom in Rf is preferably a fluorine atom. １０２ and Rf １０３ Examples of the alkyl group having 1 to 5 carbon atoms in Rf include the same alkyl groups having 1 to 5 carbon atoms as those in R, and a methyl group or an ethyl group is preferred. １０２ and Rf １０３ Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is preferred. Among these, Rf １０２ and Rf １０３ In formula (f1-1), nf is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group, and still more preferably a hydrogen atom. １ is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0340] In formula (f1-1), Rf １０１ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The hydrocarbon group containing a fluorine atom may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. In addition, the hydrocarbon group containing a fluorine atom is preferably one in which 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among these, Rf １０１ is preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, more preferably a trifluoromethyl group, —CH ２ -CF ３ , -CH ２ -CF２ -CF ３ , -CH(CF ３ ) ２ , -CH ２ -CH ２ -CF ３ , -CH ２ -CH ２ -CF ２ -CF ２ -CF ２ -CF ３ is particularly preferred.

[0341] The weight-average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. When the Mw is below the upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, while when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

[0342] In the resist composition of this embodiment, the component (F) may be used either as a single type, or as a combination of two or more types. When the resist composition contains the component (F), the amount of the component (F) relative to 100 parts by mass of the component (A1) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass.

[0343] <Organic Solvent Component (S)> The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as "component (S)"). The component (S) can be any solvent that is capable of dissolving the individual components used to form a homogeneous solution, and any solvent can be appropriately selected from among those known as solvents for conventional chemically amplified resist compositions. In the resist composition of this embodiment, the component (S) can be used either alone or as a mixed solvent of two or more different solvents. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0344] Also preferred as component (S) is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into account the compatibility of PGMEA with the polar solvent, etc. Another preferred component (S) is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone. In this case, the mass ratio of the former to the latter is preferably 70:30 to 95:5. The amount of component (S) used is not particularly limited and is appropriately determined based on the coating film thickness and a concentration that allows application to a substrate, etc. Component (S) is generally used so that the solids concentration of the resist composition is within the range of 0.1 to 20 mass%, preferably 0.2 to 15 mass%.

[0345] The resist composition of this embodiment may further contain, if desired, compatible additives such as an additional resin for improving the performance of the resist film, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, or a dye.

[0346] In the resist composition of this embodiment, after dissolving the resist material in component (S), impurities may be removed using a polyimide porous film, a polyamideimide porous film, or the like. For example, the resist composition may be filtered using a filter made of a polyimide porous film, a filter made of a polyamideimide porous film, or a filter made of a polyimide porous film and a polyamideimide porous film. Examples of the polyimide porous film and the polyamideimide porous film include those described in JP 2016-155121 A.

[0347] As explained above, the resist composition of this embodiment contains a resin component (A1) that includes a structural unit (a01) derived from a compound represented by general formula (a01-b) and a structural unit (a02) derived from a compound represented by general formula (a02-d). The resin component (A1) in the resist composition of this embodiment incorporates a structural unit (a01) that acts relatively as an acid and a structural unit (a02) that acts relatively as a base. This facilitates uniform acid generation within the resist film and also facilitates suppression of acid diffusion. Furthermore, iodine atoms are contained in one or more of the anionic and cationic moieties of the structural unit (a01) and the anionic and cationic moieties of the structural unit (a02). This enhances light absorption during exposure. Additionally, the effect of the iodine atoms increases the process tolerance for fluctuations in exposure dose. Therefore, it is presumed that the resist composition of this embodiment achieves improved lithography properties such as increased sensitivity when forming a resist pattern and reduced pattern roughness, and also widens the process margin.

[0348] (Method of Forming a Resist Pattern) The method of forming a resist pattern pertaining to the second aspect of the present invention is a method comprising the steps of forming a resist film on a support using the resist composition pertaining to the first aspect of the present invention, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. One embodiment of the method of forming a resist pattern can be exemplified by a method of forming a resist pattern as follows.

[0349] First, the resist composition of the above-described embodiment is applied to a support using a spinner or the like, and baked (post-applied bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an EUV exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without a mask pattern. Thereafter, the resist film is baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed. In the case of an alkali development process, the development is performed using an alkaline developer, and in the case of a solvent development process, a developer containing an organic solvent (organic developer) is used.

[0350] After the development treatment, a rinse treatment is preferably carried out. In the case of an alkaline development process, the rinse treatment is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse solution containing an organic solvent is preferably used. In the case of a solvent development process, after the development treatment or rinse treatment, a treatment may be carried out to remove the developer or rinse solution adhering to the pattern using a supercritical fluid. After the development treatment or rinse treatment, drying is carried out. Furthermore, in some cases, a bake treatment (post-bake) may be carried out after the development treatment.

[0351] 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.

[0352] The wavelength used for exposure is not particularly limited, and may be an ArF excimer laser, a KrF excimer laser, or a F ２Radiation such as excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. The method of forming a resist pattern of this embodiment is useful for exposing the resist film to EUV (extreme ultraviolet) or EB (electron beam) in the step of exposing the resist film.

[0353] The exposure method for the resist film may be a normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be liquid immersion exposure (liquid immersion lithography). Liquid immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure apparatus is filled in advance with a solvent (immersion medium) having a refractive index greater than that of air, and exposure (immersion exposure) is performed in this state. The liquid immersion medium is preferably a solvent having a refractive index greater than that of air and smaller than that of the resist film to be exposed, and examples thereof include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent. Water is preferably used as the liquid immersion medium.

[0354] An example of an alkaline developer used in the development treatment in the alkaline development process is a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent that can dissolve the component (A1) (component (A1) before exposure), and can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents.

[0355] 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.

[0356] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0357] 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.

[0358] 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).

[0359] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be appropriately selected from the organic solvents listed above as organic solvents used in the organic developer, as long as they do not easily dissolve the resist pattern. Typically, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. These organic solvents may be used alone or in combination with two or more. They may also be used in combination with other organic solvents or water.

[0360] 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).

[0361] According to the method of forming a resist pattern of the present embodiment as described above, the resist composition described above is used, so when forming a resist pattern, improvements in lithography properties such as increased sensitivity and reduced pattern roughness can be achieved, and a resist pattern with a wide process margin and excellent shape can be stably formed.

[0362] The resist composition of the above-described embodiment and the various materials used in the pattern formation method of the above-described embodiment (e.g., resist solvent, developer, rinse, anti-reflective coating composition, top coat composition, etc.) preferably do not contain impurities such as metals, halogen-containing metal salts, acids, alkalis, or components containing sulfur or phosphorus atoms. Examples of impurities containing metal atoms include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, or salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially free of impurities (below the detection limit of the measuring device).

[0363] (Copolymer) A third aspect of the present invention is a copolymer having a structural unit (a01) derived from a compound represented by the following general formula (a01-b), and a structural unit (a02) derived from a compound represented by the following general formula (a02-d):

[0364] [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an m-valent onium cation, and m is an integer of 1 or more. ０２ is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an n-valent onium cation, where n is an integer of 1 or more. ０１ , X ０２ , M ｍ＋ and N ｎ＋ Any one or more of the groups contains an iodine atom.]

[0365] Suitable examples of the copolymer related to the third aspect include copolymers that, in addition to the aforementioned structural unit (a01) and structural unit (a02), further include a structural unit (a1) containing an acid-decomposable group whose polarity increases when acted upon by an acid, and a structural unit (a10) represented by the following general formula (a10-1):

[0366] In formula (a10-1), R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ｘ１ is a divalent linking group or a single bond. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ represents an integer of 1 or greater, as far as valence allows.

[0367] The structural unit (a01) derived from the compound represented by the general formula (a01-b) is the same as the explanation for the structural unit (a01) above. The structural unit (a02) derived from the compound represented by the general formula (a02-d) is the same as the explanation for the structural unit (a02) above. The structural unit (a1) containing an acid-decomposable group whose polarity increases under the action of acid is the same as the explanation for the structural unit (a1) constituting the resin component (A1) above. The structural unit (a10) represented by the general formula (a10-1) is the same as the explanation for the structural unit (a10) constituting the resin component (A1) above. The copolymer related to the third aspect is the same as the explanation for the resin component (A1) above.

[0368] The component (A1) can be produced by dissolving the monomers from which each structural unit is derived 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 monomer. Alternatively, the component (A1) can be produced by dissolving a monomer from which structural unit (a01) is derived (a compound represented by general formula (a01-b)), a monomer from which structural unit (a02) is derived (a compound represented by general formula (a02-d)), and, if necessary, a monomer from which a structural unit other than these (e.g., structural unit (a10)) is derived, in a polymerization solvent, adding a radical polymerization initiator such as those described above to the solution and polymerizing the resulting monomer, followed by a deprotection reaction. During the polymerization, for example, HS-CH ２ -CH ２ -CH ２ -C(CF ３ ) ２ By using a chain transfer agent such as —OH in combination, it is possible to obtain a chain with —C(CF ３ ) ２ A copolymer having a hydroxyalkyl group in which some of the hydrogen atoms of the alkyl group have been substituted with fluorine atoms is thus introduced, and is effective in reducing development defects and LER (line edge roughness: non-uniform irregularities on the line sidewalls).

[0369] The copolymer related to the third aspect, that is, a copolymer having a structural unit (a01) derived from a compound represented by general formula (a01-b) and a structural unit (a02) derived from a compound represented by general formula (a02-d), can be used as a base component of the resist composition related to the first aspect. Furthermore, a copolymer having the structural unit (a01), the structural unit (a02), a structural unit (a1) containing an acid-decomposable group whose polarity increases under the action of acid, and a structural unit (a10) represented by general formula (a10-1) is particularly useful as a resist material for lithography exposure using EUV or EB.

[0370] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0371] <Synthesis Examples of Compounds> Compounds (a01-b31m), (a01-b32m), and (a01-b33m) were each produced by the synthesis methods shown below.

[0372] [Synthesis of Compound (a01-b31m)] 3,5-diiodosalicylic acid (40.0 g) and tetrahydrofuran (160.0 g) were charged and dissolved with stirring. 1,1'-carbonyldiimidazole (20.0 g) was added thereto, and the mixture was heated to 60°C in a water bath and stirred for 1 hour. Compound A (38.3 g) was added thereto and aged for 1 hour. Subsequently, ultrapure water (160.0 g) and methylene chloride (160.0 g) were charged thereto and stirred. After stirring was stopped, the aqueous layer was removed and further washed with ultrapure water (160 g). The organic layer was concentrated under reduced pressure, and the concentrated residue was crystallized with acetonitrile / tert-butyl methyl ether to obtain 43.2 g of a white compound (intermediate A).

[0373]

[0374] 4-Vinylbenzoic acid (9.6 g), Intermediate A (40.0 g), 4-dimethylaminopyridine (0.7 g), and dichloromethane (400.0 g) were 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 31.5 g of a white compound (Intermediate B).

[0375]

[0376] Intermediate B (30.0 g), compound B (25.0 g), dichloromethane (150.0 g), and ultrapure water (60.0 g) were stirred at room temperature and separated into layers. The organic layer was washed five times with ultrapure water (60.0 g) and then concentrated under reduced pressure to obtain 30.5 g of compound (a01-b31m).

[0377]

[0378] The resulting compound (a01-b31m) was subjected to NMR measurement, and its structure was identified from the following data. １H-NMR (DMSO-d6, 400MHz) d (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 15H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H).

[0379] [Synthesis of Compound (a01-b32m)] Compound (a01-b32m) was obtained in the same manner as in [Synthesis of Compound (a01-b31m)] above, except that Compound B was changed to Compound C.

[0380]

[0381] The resulting compound (a01-b32m) was subjected to NMR measurement, and its structure was identified from the following data. １ H-NMR (DMSO-d6, 400MHz) d (ppm) = 8.58 (d, 1H), 8.31 (d, 1H), 8.13 (d, 2H), 8. 00-7.72 (m, 14H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H).

[0382] [Synthesis of Compound (a01-b33m)] Compound (a01-b33m) was obtained in the same manner as in [Synthesis of Compound (a01-b31m)] above, except that Compound B was changed to Compound D.

[0383]

[0384] The resulting compound (a01-b33m) was subjected to NMR measurement, and its structure was identified from the following data. １ H-NMR (DMSO-d6, 400MHz) d (ppm) = 8.58 (m, 2H), 8.31 (d, 1H), 8.13 (d, 2H), 8.11 (d, 1H), 8. 00-7.72 (m, 12H), 6.92-6.85 (m, 1H), 6.07 (d, 1H), 5.49 (d, 1H), 4.67 (t, 2H), 2.37 (s, 6H).

[0385] <Synthesis Example of Copolymer> As raw material monomers, the following compounds (a10-1pre), (a10-2pre), (a1-1m), (a01-b11m), (a01-b12m), (a01-b13m), (a01-b21m), (a01-b22m), (a01-b23m), (a01-b24m), (a01-b31m), (a01-b32m), and (a Copolymers (A1-1) to (A1-26) were each produced by the synthesis method shown below using compound (a01-b33m), compound (a01-b41m); compound (a02-d11m), compound (a02-d12m), compound (a02-d13m), compound (a02-d21m), compound (a02-d31m), compound (a02-d41m), compound (a02-d51m), and compound (a02-d61m).

[0386]

[0387]

[0388]

[0389]

[0390]

[0391] [Synthesis of Copolymer (A1-1)] 10.0 g of compound (a10-1pre), 16.2 g of compound (a1-1m), 21.0 g of compound (a01-b11m), 3.8 g of compound (a02-d11m), and 12.6 g of azobis(isobutyrate) dimethyl (V-601) as a polymerization initiator were dissolved in 100 g of methyl ethyl ketone (MEK), heated to 70 ° C. under a nitrogen atmosphere, and stirred for 5 hours. Thereafter, 3.2 g of acetic acid and 60 g of methanol (MeOH) were added to the reaction solution, and a deprotection reaction was carried out at 30 ° C. for 18 hours. After completion of the reaction, the resulting reaction solution was precipitated in 1200 g of a mixed solvent of methanol and water and washed. The resulting white solid was filtered and dried under reduced pressure overnight, yielding 20.5 g of the target copolymer (A1-1).

[0392]

[0393] [Synthesis of Copolymers (A1-2) to (A1-26)] Copolymers (A1-2) to (A1-26) were obtained using the corresponding raw material monomers by the same synthesis method (radical polymerization, deprotection reaction) as in the above [Synthesis of Copolymer (A1-1)]. The structures of the obtained copolymers (A1-2) to (A1-26) are shown below.

[0394]

[0395]

[0396]

[0397]

[0398]

[0399]

[0400]

[0401]

[0402] The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) of each of the copolymers (A1-1) to (A1-26) obtained were determined by GPC measurement (standard polystyrene equivalent). Furthermore, the copolymer composition ratio (the proportion (molar ratio) of each structural unit in the structural formula) of each of the copolymers (A1-1) to (A1-26) was determined by carbon-13 nuclear magnetic resonance spectroscopy (600 MHz - １３ C-NMR).

[0403] Copolymer (A1-1): Weight-average molecular weight (MW) 10,100, molecular weight dispersion (MW / Mn) 1.55, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-2): Weight-average molecular weight (MW) 10,300, molecular weight dispersion (MW / Mn) 1.57, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-3): Weight-average molecular weight (MW) 9,900, molecular weight dispersion (MW / Mn) 1.54, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-4): Weight-average molecular weight (MW) 10,200, molecular weight dispersion (MW / Mn) 1.56, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-5): Weight-average molecular weight (MW) 10,000, molecular weight dispersion (MW / Mn) 1.53, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5.

[0404] Copolymer (A1-6): Weight-average molecular weight (MW) 10,100, molecular weight dispersion (MW / Mn) 1.59, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-7): Weight-average molecular weight (MW) 10,200, molecular weight dispersion (MW / Mn) 1.60, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-8): Weight-average molecular weight (MW) 10,000, molecular weight dispersion (MW / Mn) 1.58, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-9): Weight-average molecular weight (MW) 10,300, molecular weight dispersion (MW / Mn) 1.61, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-10): Weight-average molecular weight (MW) 9,900, molecular weight dispersion (MW / Mn) 1.56, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5.

[0405] Copolymer (A1-11): Weight-average molecular weight (MW) 9800, molecular weight dispersion (MW / Mn) 1.54, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-12): Weight-average molecular weight (MW) 9900, molecular weight dispersion (MW / Mn) 1.55, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-13): Weight-average molecular weight (MW) 10100, molecular weight dispersion (MW / Mn) 1.53, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-14): Weight-average molecular weight (MW) 10,200, molecular weight dispersion (MW / Mn) 1.54, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-15): Weight-average molecular weight (MW) 9,900, molecular weight dispersion (MW / Mn) 1.55, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5.

[0406] Copolymer (A1-16): Weight-average molecular weight (MW) 10,000, molecular weight dispersion (MW / Mn) 1.59, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-17): Weight-average molecular weight (MW) 9,900, molecular weight dispersion (MW / Mn) 1.58, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-18): Weight-average molecular weight (MW) 10,100, molecular weight dispersion (MW / Mn) 1.57, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-19): Weight-average molecular weight (MW) 10,300, molecular weight dispersion (MW / Mn) 1.60, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-20): Weight-average molecular weight (MW) 10,200, molecular weight dispersion (MW / Mn) 1.55, composite composition ratio l / m / n / o = 30 / 50 / 15 / 5.

[0407] Copolymer (A1-21): Weight average molecular weight (Mw) 10100, molecular weight dispersity (Mw / Mn) 1.58, copolymer composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-22): Weight average molecular weight (Mw) 9900, molecular weight dispersity (Mw / Mn) 1.54, copolymer composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-23): Weight average molecular weight (Mw) 10,000, molecular weight dispersity (Mw / Mn) 1.54, copolymer composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-24): weight average molecular weight (Mw) 10200, molecular weight dispersity (Mw / Mn) 1.57, copolymer composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-25): Weight average molecular weight (Mw) 10100, molecular weight dispersity (Mw / Mn) 1.55, copolymer composition ratio l / m / n / o = 30 / 50 / 15 / 5. Copolymer (A1-26): weight average molecular weight (Mw) 10200, molecular weight dispersity (Mw / Mn) 1.56, copolymer composition ratio l / m / n / o=30 / 50 / 15 / 5.

[0408] <Preparation of Resist Compositions> (Examples 1 to 29, Comparative Examples 1 to 5) The components shown in Tables 1 to 3 were mixed and dissolved to prepare the resist compositions of each example.

[0409]

[0410]

[0411]

[0412] In Tables 1 to 3, the abbreviations have the following meanings: The numbers in brackets [ ] are the blend amounts (parts by mass; solid content equivalent).

[0413] (A)-1 to (A)-26: the above-mentioned copolymers (A1-1) to (A1-26).

[0414] (A)-27: The following copolymer (A2-1). Weight average molecular weight (Mw) 10,100, molecular weight dispersity (Mw / Mn) 1.55, copolymerization composition ratio l / m / n / o=30 / 50 / 15 / 5.

[0415] (A)-28: The following copolymer (A2-2). Weight average molecular weight (Mw) 10200, molecular weight dispersity (Mw / Mn) 1.58, copolymerization composition ratio l / m / n / o=30 / 50 / 15 / 5.

[0416]

[0417] (A)-29: The following copolymer (A2-3). Weight average molecular weight (Mw) 10100, molecular weight dispersity (Mw / Mn) 1.57, copolymerization composition ratio l / m / o=35 / 59 / 6.

[0418] (A)-30: The following copolymer (A2-4). Weight average molecular weight (Mw) 10,000, molecular weight dispersity (Mw / Mn) 1.56, copolymerization composition ratio l / m / n=32 / 53 / 15.

[0419] (A)-31: The following copolymer (A2-5). Weight average molecular weight (Mw) 10200, molecular weight dispersity (Mw / Mn) 1.55, copolymerization composition ratio l / m / n=32 / 53 / 15.

[0420] The weight average molecular weight (Mw) is the weight average molecular weight calculated as standard polystyrene by GPC measurement. The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) is １３ It was determined by C-NMR.

[0421]

[0422] (B)-1: An acid generator comprising the following compound (B-1): (D)-1: An acid diffusion controller comprising the following compound (D1-1):

[0423]

[0424] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0425] <Formation of Resist Pattern> Step of Forming Resist Film: Each resist composition of the examples was applied using a spinner onto an 8-inch silicon substrate that had been treated with hexamethyldisilazane (HMDS), and the applied resist composition was pre-baked (PAB) on a hot plate at a temperature of 110°C for 60 seconds, followed by drying to form a resist film with a thickness of 50 nm.

[0426] Step of exposing resist film: Next, the resist film was subjected to drawing (exposure) using an electron beam lithography system JEOL-JBX-9300FS (manufactured by JEOL Ltd.) at an acceleration voltage of 100 kV to form a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a target size of 25 nm line width. Thereafter, post-exposure bake (PEB) treatment was performed at 100°C for 60 seconds.

[0427] Step of developing the exposed resist film: Next, alkaline development was carried out for 60 seconds at 23°C using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, a water rinse was carried out for 15 seconds using pure water. As a result, a 1:1 LS pattern with a line width of 25 nm was formed.

[0428] [Sensitivity Evaluation] The optimum exposure dose Eop (μC / cm) at which an LS pattern of the target size is formed by the above <Resist Pattern Formation> ２ The results were recorded as "Eop (μC / cm ２ ) are shown in Tables 4 to 6.

[0429] [Evaluation of LWR (Line Width Roughness)] For the LS patterns formed by the above <Formation of Resist Pattern>, 3σ, a measure of LWR, was determined. The results are shown in Tables 4 to 6 as "LWR (nm)." "3σ" represents three times the standard deviation (σ) (unit: nm) obtained from the measurement results of 400 line positions measured in the longitudinal direction of the line using a scanning electron microscope (acceleration voltage 800 V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation). The smaller the 3σ value, the smaller the roughness of the line sidewalls, meaning that an LS pattern with a more uniform width was obtained.

[0430] [Evaluation of Process Margin] The optimum exposure dose Eop (μC / cm) obtained in the above [Evaluation of Sensitivity] ２ The line dimensions of the LS patterns formed when the exposure dose was increased and decreased were measured. ２ While gradually decreasing and increasing the exposure dose, LS pattern formation was performed using the above-described <Formation of Resist Pattern>. When the exposure dose was reduced below Eop, the dimension (x) of the thickest line that could be formed in the low exposure dose area and did not produce stringy bridges between the lines was measured. When the exposure dose was increased above Eop, the dimension (y) of the thinnest line that could be formed in the high exposure dose area and did not collapse was measured. The value obtained by subtracting the line dimension (y) from the line dimension (x) was taken as the process window. The results are shown in Tables 4 to 6 as "Window (nm)." A larger process window value indicates that pattern formation is possible even with variations in the exposure dose (whether low or high), and the process margin is wider.

[0431]

[0432]

[0433]

[0434] The results shown in Tables 4 to 6 demonstrate that the resist compositions of Examples 1 to 29 employing the present invention were superior in both sensitivity and pattern roughness reduction effect, and also had a larger process window, compared to the resist compositions of Comparative Examples 1 and 2. Furthermore, the resist compositions of Examples 1 to 29 employing the present invention were superior in pattern roughness reduction effect and had a larger process window, compared to the resist compositions of Comparative Examples 3 to 5. These results demonstrate that the resist compositions of the present invention can be used to form resist patterns with improved lithography properties, such as increased sensitivity and reduced pattern roughness, while also enabling a wider process margin.

[0435] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component (A1) whose solubility in a developer changes due to the action of the acid, the resin component (A1) having a structural unit (a01) derived from a compound represented by the following general formula (a01-b), and a structural unit (a02) derived from a compound represented by the following general formula (a02-d): [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ R is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an onium cation having a valence of m, and m is an integer of 1 or more. ０２ is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an onium cation having a valence of n, where n is an integer of 1 or more. ０１ , X ０２ , M. ｍ＋ and N ｎ＋ Any one or more of the above contains an iodine atom.

2. The resist composition according to claim 1, wherein the resin component (A1) includes a copolymer having the structural unit (a01), the structural unit (a02), a structural unit (a1) containing an acid-decomposable group whose polarity increases when acted upon by an acid, and a structural unit (a10) represented by the following general formula (a10-1): In formula (a10-1), R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ｘ１ is a divalent linking group or a single bond. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ represents an integer of 1 or more, as far as atomic valence allows.

3. A method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to claim 1 or 2, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

4. A copolymer having a structural unit (a01) derived from a compound represented by the following general formula (a01-b): and a structural unit (a02) derived from a compound represented by the following general formula (a02-d): [In formula (a01-b), W ０１ is a polymerizable group-containing group. ０１ R is a divalent linking group or a single bond. ０ is a fluorinated alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a hydrogen atom. ｍ＋ is an onium cation having a valence of m. m is an integer of 1 or more. In formula (a02-d), W ０２ is a polymerizable group-containing group. ０２ is a divalent linking group or a single bond. ｎ＋ is an onium cation having a valence of n, where n is an integer of 1 or more. ０１ , X ０２ , M. ｍ＋ and N ｎ＋ Any one or more of the above contains an iodine atom.

5. The copolymer according to claim 4, which is a copolymer having the structural unit (a01), the structural unit (a02), a structural unit (a1) containing an acid-decomposable group whose polarity increases when acted upon by an acid, and a structural unit (a10) represented by the following general formula (a10-1): In formula (a10-1), R represents an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. ｘ１ is a divalent linking group or a single bond. ｘ１ is an aromatic hydrocarbon group which may have a substituent. ａｘ１ represents an integer of 1 or more, as far as atomic valence allows.

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