Resist composition and method for forming resist pattern

Abstract

The present invention relates to a resist composition comprising (A) a base material component the solubility of which in a developer changes due to an action of an acid, (B) an acid generator component that generates an acid upon exposure, and (F) a fluorine additive component, wherein the base material component (A) contains a polymer compound (A1) having: a structural unit (a1) represented by general formula (a1-1) described in the description; and a structural unit (a2) containing any one of a lactone-containing cyclic group represented by general formula (a2-1) described in the description, a-SO2-containing cyclic group, or a carbonate-containing cyclic group.

Description

Resist composition and method for forming a resist pattern

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

[0002] In lithography, for example, a resist film made of a resist material is formed on a substrate, selectively exposed to light, and then developed to form a resist pattern of a predetermined shape on the resist film. Resist materials that change so that the exposed portions of the resist film become soluble in a developer are called positive-type resists, while resist materials that change so that the exposed portions of the resist film become insoluble in a developer are called negative-type resists. In recent years, advances in lithography technology have led to rapid advances in pattern miniaturization in the manufacture of semiconductor devices and liquid crystal display devices. A common method for achieving this miniaturization is to shorten the wavelength (increase the energy) of the exposure light source. Specifically, while ultraviolet light, typically g-line and i-line, has traditionally been used, mass production of semiconductor devices is now being carried out using KrF excimer lasers and ArF excimer lasers. Furthermore, research is also being conducted on light sources with shorter wavelengths (higher energy) than these excimer lasers, such as EUV (extreme ultraviolet), EB (electron beam), and X-rays.

[0003] In this situation, resist materials are required to have lithography properties such as sensitivity to these exposure light sources or energy sources, and resolution capable of reproducing patterns with fine dimensions.

[0004] To satisfy these requirements, a chemically amplified resist composition has been used, which contains an acid generator component that generates acid upon exposure and a base component whose solubility in a developer changes due to the action of acid.

[0005] The base resin used in chemically amplified resist compositions generally contains multiple structural units in order to improve lithography properties, etc. For example, Patent Document 1 discusses a resist composition and a method of forming a resist pattern that can achieve high sensitivity, have excellent lithography properties, and are capable of forming a resist pattern with a good shape.

[0006] Japanese Patent Application Publication No. 2012-168504

[0007] As lithography technology continues to advance and resist patterns become increasingly finer, resist compositions are required to have high sensitivity to the exposure light source and good lithography properties such as reduced roughness, etc. However, with conventional resist compositions such as those described in Patent Document 1 above, there is still room for improvement in achieving both high sensitivity and good lithography 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 and a method of forming a resist pattern that can achieve high sensitivity and form a resist pattern that has excellent lithography properties.

[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 an acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition comprising a base component (A) whose solubility in a developer changes due to the action of the acid, an acid generator component (B) that generates an acid upon exposure, and a fluorine additive component (F), wherein the base component (A) comprises a structural unit (a1) represented by the following general formula (a1-1), and a lactone-containing cyclic group, —SO ２ The resist composition comprises a polymeric compound (A1) having a structural unit (a2) that contains either a -containing cyclic group or a carbonate-containing cyclic group.

[0010]

[0011] In general formula (a1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １１ represents a cyclic hydrocarbon group having 5 to 8 carbon atoms, and n represents an integer of 1 to 3.

[0012]

[0013] In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１represents 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, a carbonate-containing cyclic group, or —SO ２ represents a -containing cyclic group.]

[0014] A second aspect of the present invention is a method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition related to the first aspect, exposing the resist film to light, and developing the resist film to form a resist pattern.

[0015] According to the present invention, it is possible to provide a resist composition and a method of forming a resist pattern that can achieve high sensitivity and form a resist pattern that has excellent lithography properties.

[0016] In this disclosure, "aliphatic" is a relative concept to aromatic and is defined as meaning a group, compound, etc. that does not have aromaticity. Unless otherwise specified, "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, "alkylene group" includes linear, branched, and cyclic divalent saturated hydrocarbon groups. A "halogenated alkyl group" is a group in which some or all of the hydrogen atoms of an alkyl group have been substituted with halogen atoms, and examples of such halogen atoms include fluorine, chlorine, bromine, and iodine atoms. A "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which some or all of the hydrogen atoms of an alkyl group have been substituted with fluorine atoms. A "structural unit" refers to a monomer unit that constitutes a polymer compound (resin, polymer, copolymer). The phrase "optionally has a substituent" refers to the case in which a hydrogen atom (-H) is substituted with a monovalent group, and the case in which a methylene group (-CH ２The term "exposure" encompasses both cases where the radical (-) is substituted with a divalent group.

[0017] The "base component" refers to an organic compound having film-forming ability, and preferably an organic compound having a molecular weight of 500 or more is used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved, and in addition, it becomes easier to form nano-level resist patterns. Organic compounds used as base components are broadly classified into non-polymers and polymers. As non-polymers, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the term "low molecular weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000. As polymers, those having a molecular weight of 1000 or more are usually used. Hereinafter, the terms "resin," "polymer compound," or "polymer" refer to a polymer having 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).

[0018] The term "structural unit derived from an acrylic acid ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylic acid ester. ２ ═CH—COOH) with an organic group substituted for the hydrogen atom at the carboxyl end of the acrylate ester. The hydrogen atom bonded to the α-position carbon atom in the acrylate ester may be substituted with a substituent. The substituent (R α０ ) is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms. α０ ) is substituted with a substituent containing an ester bond, or α０This 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 the acrylic ester is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom is substituted with a substituent may be referred to as an α-substituted acrylic ester. Furthermore, acrylic esters and α-substituted acrylic esters may be collectively referred to as "(α-substituted) acrylic esters."

[0019] The alkyl group as the substituent at the α-position is preferably a linear or branched alkyl group, and specific examples thereof include alkyl groups having 1 to 5 carbon atoms (methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups). Specific examples of halogenated alkyl groups as the substituent at the α-position include groups in which some or all of the hydrogen atoms of the above-mentioned "alkyl group as the substituent at the α-position" have been substituted with halogen atoms. Examples of such halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine atoms being particularly preferred. Specific examples of hydroxyalkyl groups as the substituent at the α-position include groups in which some or all of the hydrogen atoms of the above-mentioned "alkyl group as the substituent at the α-position" have been substituted with hydroxyl groups. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1.

[0020] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. Furthermore, in the present disclosure, when a composition contains multiple substances corresponding to each component, the amount of each component in the composition means the total amount of the multiple corresponding substances present in the composition, unless otherwise specified. Furthermore, in the present disclosure, chemical structural formulas may be expressed as simplified structural formulas in which hydrogen atoms are omitted.

[0021] In the present disclosure, depending on the structure represented by the chemical formula, asymmetric carbons may exist, and enantiomers or diastereoisomers may exist. In such cases, one chemical formula represents the isomers. The isomers may be used alone or as a mixture. In the present disclosure, "% by mass" and "% by weight" are synonymous, "parts by mass" and "parts by weight" are synonymous, and "mass ratio" and "weight ratio" are synonymous.

[0022] [Resist Composition] In the present disclosure, a resist composition that forms a positive resist pattern by dissolving and removing exposed portions of a resist film is referred to as a positive resist composition, and a resist composition that forms a negative resist pattern by dissolving and removing unexposed portions of a resist film is referred to as a negative resist composition. The resist composition of this embodiment may be a positive resist composition or a negative resist composition. 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 may be for use in a solvent development process in which a developer containing an organic solvent (organic developer) is used for the development treatment. In other words, the resist composition of this embodiment may be a "positive resist composition for an alkaline development process" that forms a positive resist pattern in an alkaline development process, or a "negative resist composition for a solvent development process" that forms a negative resist pattern in a solvent development process.

[0023] A resist composition according to a first aspect of the present invention is a resist composition that generates an acid upon exposure, and whose solubility in a developer changes due to the action of the acid. The resist composition contains a base component (A) (hereinafter also referred to as “component (A)”) whose solubility in a developer changes due to the action of the acid, an acid generator component (B) (hereinafter also referred to as “component (B)”) that generates an acid upon exposure, and a fluorine additive component (F) (hereinafter also referred to as “component (F)”). The base component (A) contains a structural unit (a1) represented by the following general formula (a1-1), and a lactone-containing cyclic group, —SO ２The resist composition contains a polymeric compound (A1) (hereafter also referred to as "component (A1)") that has a structural unit (a2) that includes either a -containing cyclic group or a carbonate-containing cyclic group. When such a resist composition is used to form a resist film, high sensitivity can be achieved and a resist pattern that has excellent lithography properties can be formed.

[0024] When a resist film is formed using such a resist composition and then subjected to selective exposure, acid is generated in the exposed areas of the resist film, and the solubility of component (A) in a developer changes due to the action of the acid, while the solubility of 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.

[0025] In the resist composition according to an embodiment of the present invention, the component (A) whose solubility in a developer changes under the action of an acid is a structural unit (a1) represented by general formula (a1-1), a lactone-containing cyclic group represented by general formula (a2-1), —SO ２ The polymer compound (A1) includes a structural unit (a2) that includes either a -containing cyclic group or a carbonate-containing cyclic group.

[0026] In an embodiment of the present invention, the structural unit (a1) represented by general formula (a1-1) has a structure in which a carbon atom is present between the ester group and the cyclic hydrocarbon group, which facilitates dissociation of the acid-dissociable group described below. This is thought to facilitate the sensitivity of the resist composition. It is also thought that the contrast between exposed and unexposed areas is enhanced, resulting in the formation of a resist pattern with a good shape.

[0027] The component (A) may generate an acid upon exposure, in which case the component (A) becomes a "base component that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid." When the component (A) is a base component that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, the component (A) described below is preferably a polymer compound that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid. As such a polymer compound, a resin having a structural unit that generates an acid upon exposure can be used. As the structural unit that generates an acid upon exposure, known compounds can be used.

[0028] The resist composition according to the first embodiment of the present invention also includes an acid generator component (B) that generates an acid upon exposure. Examples of the acid generator component (B) that generates an acid upon exposure include known compounds. Furthermore, the resist composition according to the first embodiment of the present invention also includes a fluorine additive component (F). By including the fluorine additive component (F) in the resist composition, the density of the component (A) and the acid generator component in the resist film increases, thereby achieving the effect of increasing the contrast between exposed and unexposed areas. Examples of the fluorine additive component (F) include known compounds.

[0029] <Component (A)> In the resist composition of the first embodiment of the present invention, as described above, the component (A) is a base component whose solubility in a developer changes under the action of acid, and the component (A) comprises a structural unit (a1) represented by general formula (a1-1), a lactone-containing cyclic group represented by the following general formula (a2-1), —SO ２ The polymeric compound (A1) (hereinafter also referred to as "polymeric compound (A1) or component (A1)") has a structural unit (a2) containing either a -containing cyclic group or a carbonate-containing cyclic group. The polymeric compound (A1) may be one whose solubility in a developer increases under the action of an acid, or one whose solubility in a developer decreases under the action of an acid. By using the polymeric compound (A1), the polarity of the base component (A) changes before and after exposure, and therefore good development contrast can be obtained not only in an alkali development process but also in a solvent development process.

[0030] As the component (A), at least a polymeric compound (A1) is used, and other polymeric compounds and / or low molecular weight compounds may be used in combination with the polymeric compound (A1).

[0031] In the resist composition according to an embodiment of the present invention, the component (A) may use either a single type of compound, or a combination of two or more types of compounds.

[0032] Regarding the Component (A1), the component (A1) is a polymeric compound (resin component) whose solubility in a developer changes under the action of an acid. The component (A1) is composed of a structural unit (a1) represented by general formula (a1-1), a lactone-containing cyclic group represented by general formula (a2-1), —SO ２ The component (A1) contains a structural unit (a2) that contains either a -containing cyclic group or a carbonate-containing cyclic group. In addition to the structural unit (a1) and the structural unit (a2), the component (A1) may also contain other structural units as necessary.

[0033] <Structural Unit (a1)>

[0034] The structural unit (a1) represented by general formula (a1-1) is a structural unit that contains an acid-decomposable group whose polarity increases when acted upon by an acid.

[0035] 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 Among these, polar groups containing -OH in the structure (hereinafter sometimes referred to as "OH-containing polar groups") are preferred, with carboxy groups or hydroxyl groups being more preferred, and carboxy groups being particularly preferred. More specific examples of acid-decomposable groups include groups in which the polar groups are protected with acid-dissociable groups (for example, groups in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0036] Here, the term "acid-dissociable group" refers to either (i) a group having acid dissociability in which the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a part of the bond is cleaved by the action of an acid, and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Thus, when the acid-dissociable group 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.

[0037] Examples of the acid-dissociable group include those that have been proposed as acid-dissociable groups for base resins of chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed as acid-dissociable groups for base resins of chemically amplified resist compositions include "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," and "tertiary alkyloxycarbonyl acid-dissociable groups."

[0038] The structural unit (a1) is represented by the following general formula (a1-1), and is a structural unit that contains a "tertiary alkyl ester-type acid-dissociable group" as the acid-dissociable group. When the structural unit (a1) has a structure represented by general formula (a1-1), dissociation by acid occurs more easily, which has the effect of increasing the contrast between exposed and unexposed areas.

[0039]

[0040] In general formula (a1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １１ represents a cyclic hydrocarbon group having 5 to 8 carbon atoms, and n represents an integer of 1 to 3.

[0041] In general formula (a1-1), 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 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the perspective of industrial availability, a hydrogen atom or a methyl group is most preferred.

[0042] In general formula (a1-1), Ra １１ represents a cyclic hydrocarbon group having 5 to 8 carbon atoms. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be monocyclic or polycyclic, and is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane has 5 to 8 carbon atoms, preferably 5 or 6 carbon atoms. Specific examples include cyclopentane, cyclohexane, cyclononane, cyclooctane, and norbornane, with cyclopentane or cyclohexane being preferred.

[0043] 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. Specific examples of the aromatic hydrocarbon group include aromatic rings (groups obtained by removing one hydrogen atom from an aromatic hydrocarbon ring or an aromatic heterocycle (aryl group or heteroaryl group)); and groups obtained by removing one hydrogen atom from an aromatic compound containing two or more aromatic rings. The aromatic ring preferably has 5 to 8 carbon atoms, more preferably 5 to 6 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene.

[0044] Ra １１The cyclic hydrocarbon group having 5 to 8 carbon atoms represented by is an alicyclic hydrocarbon group which may have a substituent, and is preferably a monocyclic alicyclic hydrocarbon group which has no substituent. Examples of the substituent include -R Ｐ１ , -R Ｐ２ -O-R Ｐ１ , -R Ｐ２ -CO-R Ｐ１ , -R Ｐ２ -CO-O-R Ｐ１ , -R Ｐ２ -O-CO-R Ｐ１ , -R Ｐ２ -OH, -R Ｐ２ -CN or -R Ｐ２ -COOH (hereinafter, these substituents are collectively referred to as "Ra ０５ ") 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 A part or all of the hydrogen atoms of the chain saturated hydrocarbon group, the alicyclic saturated hydrocarbon group and the aromatic hydrocarbon group may be substituted with fluorine atoms. ０５ The group may have one or more of one kind of substituent, or may have one or more of each of two or more kinds of the above-mentioned substituents.

[0045] Examples of monovalent linear saturated hydrocarbon groups having 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and decyl groups. Examples of monovalent aliphatic cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, and cyclododecyl groups. Examples of monovalent aromatic hydrocarbon groups 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.

[0046] Ra １１ Preferred specific examples of the cyclic hydrocarbon group having 5 to 8 carbon atoms represented by the formula are listed below: In the following formula, * represents a bond.

[0047]

[0048] As the structural unit (a1), among the above, the structural unit (a1) represented by the general formula (a1-1) １１ is preferably a cyclic hydrocarbon group having 5 or 6 carbon atoms, more preferably a cyclic hydrocarbon group having 6 carbon atoms, and even more preferably a cyclohexyl group.

[0049] In formula (a1-1), n ​​represents an integer of 1 to 3, and preferably 1 or 2.

[0050] Specific examples of the structural unit (a1) represented by general formula (a1-1) are shown below. α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0051]

[0052] The proportion of the structural unit (a1) in the component (A1), relative to the total (100 mol%) of all structural units constituting the component (A1), is preferably 5 to 80 mol%, more preferably 5 to 75 mol%, even more preferably 10 to 70 mol%, even more preferably 30 to 70 mol%, and particularly preferably 40 to 60 mol%. By ensuring that the proportion of the structural unit (a1) is at least the lower limit of the above-mentioned preferred range, lithography properties such as sensitivity, resolution, and roughness improvement are improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0053] <Structural Unit (a2)> The component (A1) contains, in addition to the structural unit (a1), a lactone-containing cyclic group represented by the following general formula (a2-1), —SO ２ The copolymer has a structural unit (a2) that contains either a -containing cyclic group or a carbonate-containing cyclic group.

[0054]

[0055] In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 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, a carbonate-containing cyclic group, or —SO ２ represents a -containing cyclic group.]

[0056] In the structural unit (a2), Ra ２１ a lactone-containing cyclic group represented by —SO ２When the component (A1) is used to form a resist film, the -containing cyclic group or carbonate-containing cyclic group 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, improving the adhesion of the resist film to the substrate, and appropriate adjustment of the solubility during development, thereby improving lithography properties such as resolution.

[0057] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) that contains -O-C(=O)- in its ring skeleton. The lactone ring is counted as the first ring, and when there is only a lactone ring, it is called a monocyclic group, and when there is further 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.

[0058] The lactone-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following formulae (a2-r-1) to (a2-r-7).

[0059]

[0060] [In formulas (a2-r-1) to (a2-r-7), Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ 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. * is a bond.

[0061] In the general formulas (a2-r-1) to (a2-r-7), Ra' ２１The 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 Examples of the halogen atom in Ra' include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. 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.

[0062] Ra' ２１ In the formula, -COOR" and -OC(=O)R", R" each represents a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or -SO ２The 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 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, a tricycloalkane, or a tetracycloalkane. More specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; 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) above. The carbonate-containing cyclic group in R" is the same as the carbonate-containing cyclic group described below, and specific examples thereof include groups represented by the general formulae (ax3-r-1) to (ax3-r-3). -SO in R" ２ The -containing cyclic group includes the -SO group described below. ２ Ra' is the same as the -containing cyclic group, and specific examples thereof include groups represented by general formulae (a5-r-1) to (a5-r-4). 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.

[0063] 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.

[0064] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) and other lactone-containing cyclic groups are listed below.

[0065]

[0066]

[0067] "-SO ２ -containing cyclic group" means a group having a -SO ２ represents a cyclic group containing a ring containing -, specifically, -SO ２ The sulfur atom (S) in - forms a part of the ring skeleton of the cyclic group. ２ The ring containing - is counted as the first ring, and when there is only this ring, it is called a monocyclic group, and when there is further ring structure, it is called a polycyclic group regardless of the structure. ２ The -containing cyclic group may be a monocyclic group or a polycyclic group. ２ The -containing cyclic group is particularly one that does not contain an -O-SO group in its ring skeleton. ２ Cyclic groups containing -, i.e., -O-SO ２ It is preferred that the —O—S— in — is a cyclic group containing a sultone ring forming part of the ring skeleton. ２More specific examples of the -containing cyclic group include groups represented by the following general formulae (a5-r-1) to (a5-r-4).

[0068]

[0069] [In the formula, Ra' ５１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom, and n' is an integer of 0 to 2. * is a bond.

[0070] In the general formulae (a5-r-1) and (a5-r-2), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3), and (a2-r-5). ５１ The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″, and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each selected from the group consisting of Ra′ ２１ Examples of the groups represented by general formulae (a5-r-1) to (a5-r-4) include the same groups as those mentioned above. Specific examples of the groups represented by general formulae (a5-r-1) to (a5-r-4) are listed below. In the formulae, "Ac" represents an acetyl group. * represents a bond.

[0071]

[0072]

[0073]

[0074] The term "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -O-C(=O)-O- in its ring skeleton. The carbonate ring is counted as the first ring, and when there is only a carbonate ring, it is called a monocyclic group, and when there is furthermore another ring structure, it is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group. There are no particular limitations on the carbonate-containing cyclic group, and any group can be used. Specific examples include groups represented by the following general formulae (ax3-r-1) to (ax3-r-3), respectively.

[0075]

[0076] [In the formula, Ra' ｘ３１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, or an oxygen atom or a sulfur atom, p' is an integer of 0 to 3, and q' is 0 or 1. * is a bond.

[0077] In the general formulae (ax3-r-2) to (ax3-r-3), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3) and (a2-r-5). ｘ３１ The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″, and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each selected from the group consisting of Ra′ ２１ Specific examples of the groups represented by general formulae (ax3-r-1) to (ax3-r-3) are listed below.

[0078]

[0079] In the formula (a2-1), R is the same as R in the general formula (a1-1). R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is particularly preferred.

[0080] 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.

[0081] Optionally substituted divalent hydrocarbon group: Ya ２１ When is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group.

[0082] ...Ya ２１ The aliphatic hydrocarbon group in the above means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0083] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0084] 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.

[0085] ...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), which 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 within a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon groups include those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, specifically cyclopentane, cyclohexane, etc. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0086] 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. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms. The cyclic aliphatic hydrocarbon group may have some of the carbon atoms constituting its ring structure substituted with a substituent containing a heteroatom. The substituent containing a hetero atom includes —O—, —C(═O)—O—, —S—, and —S(═O) ２ -, -S(=O) ２ —O— is preferred.

[0087] Divalent linking group containing a hetero atom: Ya ２１ is a divalent linking group containing a hetero atom, preferred examples of the linking group 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 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 ２２ are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m" is an integer of 0 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group 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 above-mentioned Ya ２１ Examples of the divalent linking group include the same as those (divalent hydrocarbon groups which may have a substituent) mentioned in the description of the divalent linking group in Y 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. ２２is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. ２１ -C(=O)-O] ｍ” -Y ２２ In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, 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.

[0088] Among the above, Ya ２１ is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof.

[0089] In the formula (a2-1), Ra ２１ is a lactone-containing cyclic group, —SO ２ -containing cyclic group or carbonate-containing cyclic group. ２１ the lactone-containing cyclic group, —SO ２Suitable examples of the -containing cyclic group and the carbonate-containing cyclic group include the groups represented by the above-mentioned general formulae (a2-r-1) to (a2-r-7), (a5-r-1) to (a5-r-4), and (ax3-r-1) to (ax3-r-3). ２１ is, among the above, a lactone-containing cyclic group or —SO ２ -containing cyclic groups are preferred, lactone-containing cyclic groups are more preferred, and groups represented by any of the general formulae (a2-r-1) to (a2-r-7) are even more preferred, and groups represented by the general formulae (a2-r-1) or (a2-r-2) are particularly preferred. Specifically, any of the groups represented by the formulae (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) are preferred, and any of the groups represented by the formulae (r-lc-1-1) to (r-lc-1-7), and (r-lc-2-1) to (r-lc-2-13) are more preferred.

[0090] Specific preferred examples of the structural unit represented by formula (a2-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0091]

[0092] The structural unit (a2) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) relative to the total (100 mol%) of all structural units constituting the component (A1) is preferably 10 to 65 mol%, more preferably 20 to 65 mol%, even more preferably 30 to 60 mol%, and particularly preferably 40 to 60 mol%. When the proportion of the structural unit (a2) is at least the preferred lower limit, the effects described above can be fully achieved by including the structural unit (a2). 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.

[0093] <<Other Structural Units>> The component (A1) may contain other structural units as necessary in addition to the structural units (a1) and (a2) described above. Examples of other structural units include a structural unit (a3) ​​that includes a polar group-containing aliphatic hydrocarbon group.

[0094] In a resist composition according to an embodiment of the present invention, because properties during ArF lithography can be more easily improved, it is preferable that the component (A1) does not contain, as structural units, a structural unit (st) derived from styrene or a styrene derivative; or a structural unit derived from hydroxystyrene or a hydroxystyrene derivative.

[0095] Regarding the structural unit (a3): In addition to the structural unit (a1) and the structural unit (a2), the component (A1) may further include a structural unit (a3) ​​containing a polar group-containing aliphatic hydrocarbon group (provided that this does not correspond to the structural unit (a1) or the structural unit (a2)). That is, it is preferable that the resin component (A1) further includes a structural unit (a3) ​​containing a polar group-containing aliphatic hydrocarbon group. When the component (A1) includes the structural unit (a3), the hydrophilicity of the component (A) is enhanced, contributing to improved resolution. In addition, the acid diffusion length can be appropriately adjusted.

[0096] Examples of polar groups include hydroxyl groups, cyano groups, carboxy groups, and hydroxyalkyl groups in which some of the hydrogen atoms of an alkyl group have been substituted with fluorine atoms, with hydroxyl groups being particularly preferred. Examples of aliphatic hydrocarbon groups include linear or branched hydrocarbon groups (preferably alkylene groups) having 1 to 10 carbon atoms, and cyclic aliphatic hydrocarbon groups (cyclic groups). The cyclic group may be either a monocyclic group or a polycyclic group, and can be appropriately selected from the many groups proposed for use in resins for ArF excimer laser resist compositions, for example.

[0097] When the cyclic group is a monocyclic group, it more preferably has 3 to 10 carbon atoms. Among these, structural units derived from acrylate esters containing an aliphatic monocyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which some of the alkyl group's hydrogen atoms are substituted with fluorine atoms are more preferred. Examples of such monocyclic groups include groups in which two or more hydrogen atoms have been removed from a monocycloalkane. Specific examples include groups in which two or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane, cyclohexane, or cyclooctane. Of these monocyclic groups, groups in which two or more hydrogen atoms have been removed from cyclopentane and groups in which two or more hydrogen atoms have been removed from cyclohexane are industrially preferred.

[0098] When the cyclic group is a polycyclic group, the polycyclic group more preferably has 7 to 30 carbon atoms. Among these, structural units derived from acrylate esters containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which some of the alkyl group's hydrogen atoms are substituted with fluorine atoms are more preferred. Examples of such polycyclic groups include groups obtained by removing two or more hydrogen atoms from bicycloalkanes, tricycloalkanes, tetracycloalkanes, etc. Specific examples include groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, groups obtained by removing two or more hydrogen atoms from adamantane, groups obtained by removing two or more hydrogen atoms from norbornane, and groups obtained by removing two or more hydrogen atoms from tetracyclododecane are industrially preferred.

[0099] The structural unit (a3) ​​is not particularly limited, and any structural unit can be used as long as it contains a polar group-containing aliphatic hydrocarbon group. A preferred structural unit (a3) ​​is a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and which contains a polar group-containing aliphatic hydrocarbon group. When the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a preferred structural unit (a3) ​​is a structural unit derived from a hydroxyethyl ester of acrylic acid. Furthermore, when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a polycyclic group, preferred structural units for the structural unit (a3) ​​include structural units represented by the following formulas (a3-1), (a3-2), and (a3-3); and when the hydrocarbon group is a monocyclic group, preferred structural units include structural units represented by formula (a3-4).

[0100]

[0101] [In the formula, R is the same as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t' is an integer of 1 to 3, l is an integer of 0 to 5, and s is an integer of 1 to 3.]

[0102] In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, the hydroxyl group is preferably bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, the hydroxyl group is preferably bonded to the 3rd position of the adamantyl group. j is preferably 1, and the hydroxyl group is particularly preferably bonded to the 3rd position of the adamantyl group.

[0103] In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5- or 6-position of the norbornyl group.

[0104] In formula (a3-3), t' is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxyl group of the acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5- or 6-position of the norbornyl group.

[0105] In formula (a3-4), t' is preferably 1 or 2. l is preferably 0 or 1. s is preferably 1. The fluorinated alkyl alcohol is preferably bonded to the 3- or 5-position of the cyclohexyl group.

[0106] The structural unit (a3) ​​contained in the component (A1) may be one type, or two or more types. When the component (A1) contains the structural unit (a3), the proportion of the structural unit (a3) ​​is preferably 1 to 30 mol %, more preferably 2 to 25 mol %, and even more preferably 5 to 20 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a3) ​​is at least the preferred lower limit, the effects of including the structural unit (a3) ​​described above can be fully obtained, while by ensuring that the proportion is at most the preferred upper limit, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0107] The component (A1) contained in the resist composition may be used alone, or two or more types may be used in combination. In the resist composition according to the embodiment of the present invention, the component (A1) may be a polymeric compound having a repeating structure of the structural unit (a1) and the structural unit (a2). The component (A1) is preferably a polymeric compound having a repeating structure of the structural unit (a1) and two or more types of the structural unit (a2). In addition to the combination of the above two structural units, the structural units described above may be further combined as a third or three or more structural units as appropriate to achieve the desired effect.

[0108] Examples of combinations of three or more structural units include combinations of the structural unit (a1), the structural unit (a2), and the structural unit (a3).

[0109] Preferred examples of the component (A1) include polymeric compounds having a repeating structure of the structural unit (a1) and the structural unit (a2); polymeric compounds having a repeating structure of the structural unit (a1) and two types of structural units (a2); and polymeric compounds having a repeating structure of the structural unit (a1), the structural unit (a2), and the structural unit (a3).

[0110] Component (A1) can be produced by dissolving the monomers that derive each structural unit in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing. Alternatively, component (A1) can be produced by dissolving the monomers that derive structural units (a1) and (a2), and, if necessary, a monomer that derives structural units other than structural units (a1) and (a2), in a polymerization solvent, adding a radical polymerization initiator such as those described above to the solution and polymerizing, 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).

[0111] 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.

[0112] Regarding base components other than component (A1), the resist composition according to an embodiment of the present invention may use, as the component (A), a base component other than the component (A1), whose solubility in a developer changes under the action of an acid. There are no particular restrictions on the base component other than component (A1), and it can be arbitrarily selected from the many base components conventionally known for use in chemically amplified resist compositions, and it is also possible to use either a single polymeric compound or a low molecular weight compound, or a combination of two or more types.

[0113] The proportion of the component (A1) within the component (A), relative to the total mass of the component (A), is preferably 25 mass% or more, more preferably 50 mass% or more, and even more preferably 75 mass% or more, and may even be 100 mass%. When this proportion is 25 mass% or more, a resist pattern that exhibits excellent lithography properties is more easily formed.

[0114] In the resist composition according to an embodiment of the present invention, the amount of the component (A) is preferably from 3 to 25 mass %, more preferably from 5 to 20 mass %, and even more preferably from 8 to 16 mass %.

[0115] <Acid Generator Component (B)> In addition to the component (A), the resist composition according to an embodiment of the present invention further contains an acid generator component (B) (hereinafter referred to as "component (B)") that generates 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) preferably contains an ionic compound, and more preferably contains a compound (B1) (hereinafter referred to as "component (B1)") composed of an onium salt.

[0116] Regarding the component (B1): Examples of the component (B1) include a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)") and a compound represented by the following general formula (b-2) (hereinafter also referred to as "component (b-2)").

[0117] (Compound Represented by General Formula (b-1)) The acid generator component (B) may contain a compound represented by the following general formula (b-1).

[0118]

[0119] [In general formula (b-1), R ｂ１ represents a polycyclic hydrocarbon group which may have a substituent or a monovalent hydrocarbon group having 17 to 50 carbon atoms and a steroid skeleton. However, the hydrocarbon group may contain a heteroatom. １ represents a single bond or a divalent linking group containing a hetero atom. ｂ１ represents an alkylene group having two or more carbon atoms, a fluorinated alkylene group, or an ester group. ｆ１ represents a hydrogen atom, a fluorine atom, or an alkyl group which may contain a fluorine atom; m is an integer of 1 or more; M ｍ＋ represents an m-valent organic cation.

[0120] [anion moiety (R ｂ１ -Y ｂ１ -V ｂ１ -CFR ｆ１ -SO ３ － )] In the general formula (b-1), R ｂ１ represents a monovalent hydrocarbon group having 17 to 50 carbon atoms and a polycyclic hydrocarbon group steroid skeleton which may have a substituent. ｂ１ Examples of the polycyclic hydrocarbon group represented by include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, tetracycloalkane, or the like having 7 to 30 carbon atoms. Specific examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane.

[0121] Among these polycyclic groups, a group in which one hydrogen atom has been removed from adamantane, a group in which one hydrogen atom has been removed from norbornane, and a group in which one hydrogen atom has been removed from tetracyclododecane are preferred, and a group in which one hydrogen atom has been removed from adamantane and a group in which one hydrogen atom has been removed from norbornane are more preferred. ｂ１ The polycyclic hydrocarbon group represented by the formula (I) preferably has an adamantane skeleton or a norbornane skeleton.

[0122] These polycyclic hydrocarbon groups may have a substituent. Examples of the substituent in the polycyclic hydrocarbon 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. Of these, a hydroxyl group and an alkyl group having 1 to 5 carbon atoms are preferred, and a hydroxyl group is more preferred.

[0123] R ｂ１ The "steroid skeleton" in the monovalent hydrocarbon group having 17 to 50 carbon atoms and a steroid skeleton represented by formula (St) means a ring structure represented by formula (St) below, in which three six-membered rings and one five-membered ring are fused together.

[0124]

[0125] In the above formula (St), the numbers adjacent to the carbon atoms indicate the carbon numbers. In this specification, when referring to the positions of the carbon atoms in the steroid skeleton, the carbon numbers shown in the above formula (St) are used.

[0126] R ｂ１ The steroid skeleton of the formula (St) may contain a substituent. For example, the ring structure represented by formula (St) may have, as a substituent, an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group), a carboxy group, an oxo group (═O), an alkoxy group, an alkylcarbonyloxy group (preferably an acetoxy group), a formyloxy group (HC(═O)—O—), a hydroxyl group, a lactone-containing cyclic group, or the like. The lactone-containing cyclic group may have one or more double bonds in the ring structure. The number of double bonds is not particularly limited, but is preferably one.

[0127] R ｂ１ The number of carbon atoms in the hydrocarbon group having a steroid skeleton represented by is 17 to 50, preferably 17 to 40, more preferably 17 to 30, and particularly preferably 17 to 22. ｂ１ The number of carbon atoms includes the carbon atoms constituting the steroid skeleton, and also includes the carbon atoms in the substituents bonded to the steroid skeleton.

[0128] In the formula (b-1), Y ｂ１ represents a single bond or a divalent linking group containing a hetero atom. The hetero atom in the divalent linking group containing a hetero atom preferably contains an oxygen atom, but may contain a hetero atom other than an oxygen atom. Examples of hetero atoms other than an oxygen atom include a nitrogen atom and a sulfur atom. Y ｂ１Examples of the divalent linking group containing a hetero atom in the formula (I) include non-hydrocarbon heteroatom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an amide bond (-C(=O)-NH-, -NH-C(=O)-), a carbonyl group (-C(=O)-), and a carbonate bond (-O-C(=O)-O-); and combinations of such non-hydrocarbon heteroatom-containing linking groups with alkylene groups. ２ Preferably, Y ｂ１ The divalent linking group containing a hetero atom in the formula (1) is a divalent linking group containing at least one functional group selected from the group consisting of a carboxylate group, an ether group, a carbonate group, a carbonyl group, and an amide group. Examples of such combinations include linking groups represented by the following formulas (y-a1-1) to (y-a1-8):

[0129]

[0130] [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.

[0131] V' １０２ The divalent saturated hydrocarbon group in V' is preferably an alkylene group having 1 to 30 carbon atoms. １０２ The alkylene 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.

[0132] V' １０１ and V' １０２ The alkylene group in V' may be a linear alkylene group or a branched alkylene group. １０１ and V' １０２ Specific examples of the alkylene group in ２ -]; -CH(CH ３ ) -, -CH(CH ２ CH３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; ethylene groups [-CH ２ CH ２ -]; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, etc.; a trimethylene group (n-propylene group) [—CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ an alkyltrimethylene group such as -; a tetramethylene group [-CH ２ CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, etc.; an alkyltetramethylene group such as a pentamethylene group [—CH ２ CH ２ CH ２ CH ２ CH ２In addition, some of the methylene groups in the alkylene groups exemplified above may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. As the aliphatic cyclic group, a cyclohexylene group, a 1,5-adamantylene group, or a 2,6-adamantylene group is preferred.

[0133] Y ｂ１ As the linking group, a divalent linking group containing an ester bond or an ether bond is preferable, the linking groups represented by the above formulas (y-al-1) to (y-al-6) are more preferable, and the linking groups represented by the above formulas (y-al-1) to (y-al-3) and (y-al-6) are further preferable.

[0134] In the formula (b-1), V ｂ１ represents an alkylene group having two or more carbon atoms, a fluorinated alkylene group, or an ester group. ｂ１ The alkylene group or fluorinated alkylene group in may be linear or branched, but is preferably linear. ｂ１ The alkylene group having 2 or more carbon atoms in the formula (V) preferably has 2 to 4 carbon atoms, and more preferably has 2 to 3 carbon atoms. ｂ１ The fluorinated alkylene group in the formula (V) includes a group in which some or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms. ｂ１ The fluorinated alkylene group in R ｆ１ Preferably, the carbon atom adjacent to the carbon atom to which is bonded has at least one fluorine atom or a fluorinated alkylene group having 1 to 3 carbon atoms. ｂ１ Particularly preferred examples of include an ester group and a fluorinated alkylene group having 1 to 3 carbon atoms. The ester group and the fluorinated alkylene group having 1 to 3 carbon atoms are preferably Y ｂ１ -V ｂ１ But Y ｂ１ -(-O-(C=O)-, Y ｂ１ - (CH ２ ) ｎ -CHF- or Y ｂ１ - (CH ２ ) ｎ -CF ２- (n is an integer of 0 to 2) is preferred.

[0135] Specific examples of the anion moiety of the compound represented by general formula (b-1) are listed below. In the formula, k represents an integer of 2 to 5. However, the anion moiety in component (B1) is not limited to these specific examples.

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] (Compound Represented by General Formula (b-2)) The acid generator component (B) may contain a compound represented by the following general formula (b-2).

[0142]

[0143] [In general formula (b-2), R １ ~R ３ are each independently an at least partially fluorinated alkyl or cycloalkyl group, or R １ ~R ３ At least two of these may be bonded to form a fluorinated alkylene group. m is an integer of 1 or more, and M ｍ＋ is an m-valent organic cation.

[0144] [Anion moiety] In general formula (b-2), R １ ~R ３ are each independently an at least partially fluorinated alkyl group (preferably having 1 to 8 carbon atoms) or cycloalkyl group (preferably having 3 to 8 carbon atoms), or R １ ~R ３ At least two of R are bonded to each other to form a fluorinated alkylene group. １ ~R ３and preferably each independently represent a fluorinated alkyl group (preferably having 1 to 8 carbon atoms) or a fluorinated cycloalkyl group (preferably having 3 to 8 carbon atoms).

[0145] R １ ~R ３ Examples of the fluorinated alkyl group represented by the formula (I) include perfluoro or partially fluorinated alkyl groups, such as a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-butyl group, a heptafluoro-n-propyl group, a heptafluoro-i-propyl group, a nonafluoro-n-butyl group, a nonafluoro-2-methylpropyl group, a nonafluoro-1-methylpropyl group, a nonafluoro-t-butyl group, a perfluoro-n-pentyl group, a perfluoroneopentyl group, a perfluoro-n-hexyl group, a perfluoro-n-heptyl group, and a perfluoro-n-octyl group.

[0146] R １ ~R ３ Examples of the fluorinated cycloalkyl group represented by the formula (I) include groups in which at least one hydrogen atom of a cycloalkyl group has been substituted with a fluorine atom (fluorocycloalkyl group), such as 3- to 20-membered fluorocycloalkyl groups such as monofluorocyclopentyl, difluorocyclopentyl, nonafluorocyclopentyl, monofluorocyclohexyl, difluorocyclohexyl, and undecafluorocyclohexyl. The fluorocycloalkyl group is preferably a 5- to 20-membered ring, and more preferably a 5- to 15-membered ring.

[0147] R １ ~R ３Examples of the fluorinated alkylene group having at least two of the above bonded thereto include perfluoro or partially fluorinated alkylene groups, such as difluoromethylene group, tetrafluoroethylene group, hexafluoro-n-propylene group, hexafluoro-i-propylene group, octafluoro-n-butylene group, octafluoro-2-methylpropylene group, octafluoro-1-methylpropylene group, octafluoro-t-butylene group, perfluoro-n-pentylene group, perfluoroneopentylene group, perfluoro-n-hexylene group, perfluoro-n-heptylene group, and perfluoro-n-octylene group.

[0148] Preferable examples of the anion moiety of the compound represented by formula (b-2) include the following compounds.

[0149]

[0150] {Cation moiety} In the general formula (b-1) and the general formula (b-2), M ｍ＋ represents an m-valent onium cation. Among these, sulfonium cation and iodonium cation are preferred. m is an integer of 1 or more.

[0151] Preferred cationic moieties ((M ｍ＋ ) １／ｍ ) includes organic cations represented by the following general formulas (ca-1) to (ca-3), respectively.

[0152]

[0153] [In the formula, R ２０１ ~R ２０７ R each independently represents an aryl group, an alkyl group, or an alkenyl group which may have a substituent. ２０１ ~R ２０３ , R ２０６ ~R ２０７ 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. ２１０represents an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted —SO ２ -containing cyclic group. ２０１ represents —C(═O)— or —C(═O)—O—.]

[0154] 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 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7):

[0155]

[0156] [In the formula, R' ２０１ are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0157] Optionally substituted cyclic group: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0158] R' ２０１The 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.

[0159] 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 30 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.

[0160] 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.

[0161] 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.

[0162] 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), —SO 2 represented by the general formulae (a5-r-1) to (a5-r-4), ２ -containing cyclic groups, and heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16).

[0163]

[0164] 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, with a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group being most preferred. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, with a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group being more preferred, with a methoxy group and an ethoxy group being most preferred. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, and 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

[0165] 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. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decanyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, isohexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, heneicosyl, and docosyl groups. 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.

[0166] 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 butynyl 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, a linear alkenyl group is preferred, a vinyl group or a propenyl group is more preferred, and a vinyl group is particularly preferred.

[0167] 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:

[0168] R' ２０１ Examples of the optionally substituted cyclic group, optionally substituted chain alkyl group, or optionally substituted chain alkenyl group include those mentioned above, as well as optionally substituted cyclic groups or optionally substituted chain alkyl groups.

[0169] 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); ２ -containing cyclic groups are preferred.

[0170] In the above general formulas (ca-1) to (ca-3), R ２０１ ~R ２０３ , R ２０６ ~R ２０７ When they are bonded to each other to form a ring together with the sulfur atom in the formula, they are not substituted with heteroatoms such as sulfur atoms, oxygen atoms, and nitrogen atoms, or with carbonyl groups, -SO-, -SO ２ -, -SO ３ -, -COO-, -CONH- or -N(R Ｎ )-(the R Ｎ is an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0171] R２０８ ~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.

[0172] R ２１０ represents an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted —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 -SO which may have a substituent ２ Examples of the -containing cyclic group include "-SO ２ -containing polycyclic group" is preferred, and a group represented by the above general formula (a5-r-1) is more preferred.

[0173] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas (ca-1-1) to (ca-1-68).

[0174]

[0175]

[0176]

[0177] [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.]

[0178]

[0179]

[0180]

[0181] [In the formula, R” ２０１ is a hydrogen atom or a substituent, and the substituent is the same as R ２０１ ~R ２０７ The substituents are the same as those exemplified as the substituents that may be possessed by

[0182] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0183] 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).

[0184]

[0185] Among the above, the cation part ((M ｍ＋ ) １／ｍ ) is preferably a cation represented by general formula (ca-1). As the cation represented by general formula (ca-1), a cation represented by any one of the above formulas (ca-1-1) to (ca-1-54) is preferred, and a cation represented by any one of the above formulas (ca-1-1) to (ca-1-15) is more preferred.

[0186] Regarding the (B2) component: The (B) component may further contain an acid generator component (hereinafter referred to as "component (B2)") that does not fall under the category of the (B1) component described above. The (B2) component is not particularly limited as long as it generates acid upon exposure and does not fall under the category of the (B1) component described above, and can be arbitrarily selected from known components. Examples of the (B2) component include a wide variety of acid generators, such as oxime sulfonate acid generators; diazomethane acid generators such as bisalkyl or bisaryl sulfonyl diazomethanes and poly(bissulfonyl) diazomethanes; nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, and disulfone acid generators.

[0187] In the resist composition according to the embodiment of the present invention, the component (B) may be used alone, or two or more types may be used in combination. In the resist composition according to the embodiment of the present invention, the amount of the component (B) relative to 100 parts by mass of the component (A) is preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 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, when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, which is preferable because the storage stability of the resist composition is improved.

[0188] <Fluorine Additive Component (F)> The resist composition according to an embodiment of the present invention contains a fluorine additive component (hereafter referred to as "component (F)"). The component (F) is a hydrophobic resin, different from the component (A), used to impart water repellency to the resist film, and is prone to uneven distribution on the surface of the resist film. For this reason, by using the component (F) in the resist composition, the fluorine additive component in the resist film is reduced, and the density of the component (A) and the acid generator component is increased, thereby enhancing the contrast between exposed and unexposed areas and improving the lithography properties of the resist film. Examples of the component (F) that can be used include fluorine-containing polymeric compounds described in JP 2010-002870 A, JP 2010-032994 A, JP 2010-277043 A, JP 2011-13569 A, and JP 2011-128226 A. More specifically, the component (F) can be a polymer having a structural unit (f1) represented by the following general formula (f1-1). This polymer is preferably a polymer (homopolymer) consisting solely of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate.

[0189]

[0190] In general formula (f1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 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 represents an organic group containing a fluorine atom.]

[0191] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as R in general formula (a1-1). R is preferably a hydrogen atom or a methyl group. １０２ and Rf １０３ Examples of the halogen atom in Rf include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred. １０２ and Rf １０３ Examples of the alkyl group having 1 to 5 carbon atoms in 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. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. 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, and more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group. １ is an integer of 0 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

[0192] In formula (f1-1), Rf １０１is 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 -CF ２ -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.

[0193] 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.

[0194] In the resist composition according to an embodiment of the present invention, 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 component (F) is typically used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

[0195] <Other Components> The resist composition according to an embodiment of the present invention may further contain other components in addition to the above-described components (A), (B), and (F). Examples of other components include the following components (D) and (S).

[0196] <Acid Diffusion Controller Component (D)> In addition to the components (A), (B), and (F), the resist composition according to an embodiment of the present invention may further contain an acid diffusion controller 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 acid diffusion control properties, 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 (D1) (component (D1)) is preferred from the viewpoint of resolution.

[0197] 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, thereby improving resolution 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 may be a carboxylate, sulfonate, sulfonimide, etc., with a carboxylate being preferred from the perspective of quenching ability. Preferred examples of the component (D1) include one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)"). The components (d1-1) to (d1-3) do not function as quenchers in the exposed areas of the resist film because they decompose and lose their acid diffusion control properties (basicity), but they function as quenchers in the unexposed areas of the resist film.

[0198]

[0199] [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. ２ In 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.

[0200] {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 １As the substituent, an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent is preferred. Substituents 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). Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (a polycyclic structure consisting of a bicyclooctane skeleton and another ring structure). The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; and branched alkyl groups such as 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, and 4-methylpentyl groups.

[0201] 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 atoms other than fluorine atoms. Examples of atoms other than fluorine atoms include oxygen atoms, sulfur atoms, and nitrogen atoms. Rd １As the alkyl group, a fluorinated alkyl group in which some or all of the hydrogen atoms constituting the linear alkyl group have been substituted with fluorine atoms is preferred, and a fluorinated alkyl group in which all of the hydrogen atoms constituting the linear alkyl group have been substituted with fluorine atoms (linear perfluoroalkyl group) is particularly preferred.

[0202] Specific examples of preferred anion moieties of the component (d1-1) are shown below.

[0203]

[0204] ...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-1-68) being even more preferred. One type of component (d1-1) may be used alone, or two or more types may be used in combination.

[0205] {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). ２is 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.

[0206] Specific examples of preferred anion moieties of component (d1-2) are shown below.

[0207]

[0208] 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.

[0209] {Component (d1-3)} Anion portion In formula (d1-3), Rd ３ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and 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.

[0210] 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, and２０１ 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.

[0211] 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.

[0212] Rd ４ The cyclic group in ２０１ Examples 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.

[0213] 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.

[0214] Specific examples of preferred anion moieties of component (d1-3) are shown below.

[0215]

[0216]

[0217] 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.

[0218] The component (D1) may be any one of the components (d1-1) to (d1-3) or a combination of two or more thereof. For example, any one of the components (d1-1) and any one of the components (d1-2) may be used in combination.

[0219] When the resist composition contains the component (D1), the amount of the component (D1) in the resist composition relative to 100 parts by mass of the component (A) is preferably 1 to 25 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 10 to 15 parts by mass.

[0220] When the amount of the component (D1) is at least as large as the preferred lower limit, particularly good lithography properties and resist pattern shape are likely to be obtained, while when it is at most the upper limit, good sensitivity can be maintained and excellent throughput can be achieved.

[0221] 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.

[0222] 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 5 to 10 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0223] 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.

[0224] 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.

[0225] 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, or N-tert-butoxycarbonylpyrrolidine.

[0226] From the viewpoint of acid diffusion controllability (basicity), the component (D2) is preferably an aliphatic amine, more preferably a chain aliphatic amine, and even more preferably a chain alkylamine. The chain alkyl group of the chain alkylamine preferably has 5 to 10 carbon atoms. Among these, dialkylamines or trialkylamines having a linear alkyl group of 5 to 10 carbon atoms are preferred, and trialkylamines are more preferred.

[0227] 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 0.005 to 5 parts by mass per 100 parts by mass of the component (A). By ensuring that the amount is within this range, the resist pattern shape and stability over time during storage can be improved.

[0228] <Organic Solvent Component (S)> The resist composition according to an embodiment of the present invention can be produced by dissolving a resist material in an organic solvent component (hereafter referred to as "component (S)"). In the resist composition according to an embodiment of the present invention, the component (S) may be used alone, or as a mixed solvent of two or more different solvents. Of these, PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), γ-butyrolactone, EL (ethyl lactate), and cyclohexanone are preferred.

[0229] Also preferred as the (S) component is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into consideration the compatibility of PGMEA with the polar solvent, etc. Also preferred as the (S) component is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone. In this case, the mass ratio of the former to the latter is preferably 70:30 to 95:5. The amount of the (S) component is not particularly limited and is appropriately set according to the coating film thickness at a concentration that allows application to a substrate, etc. The (S) component is generally used so that the solids concentration of the resist composition is within the range of 0.1 to 20 mass%, preferably 0.2 to 15 mass%.

[0230] The resist composition according to the embodiment of the present invention may further contain, if desired, compatible additives such as additional resins for improving the performance of the resist film, dissolution inhibitors, plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like.

[0231] In the resist composition according to an embodiment of the present invention, 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.

[0232] (Method of forming a resist pattern) A method of forming a resist pattern according to a second aspect of the present invention is a method comprising the steps of forming a resist film on a support using the resist composition of the above-described embodiment, exposing the resist film to light, and developing the resist film to form a resist pattern. One embodiment of the method of forming a resist pattern is, for example, a method of forming a resist pattern carried out as follows.

[0233] First, the resist composition of the above-described embodiment is applied to a support using a spinner or the like, and baked (post-applied bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an ArF lithography device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without a mask pattern. The resist film is then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed. In the case of an alkali development process, the development is performed using an alkaline developer, and in the case of a solvent development process, a developer containing an organic solvent (organic developer) is used.

[0234] 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.

[0235] 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.

[0236] The wavelength used for exposure is not particularly limited, and may be an ArF excimer laser, a KrF excimer laser, or a F ２ Radiation such as excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, or soft X-ray can be used.

[0237] 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.

[0238] An example of an alkaline developer used in the development treatment in the alkaline development process is a 0.1 to 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent that can dissolve component (A) (component (A) before exposure), and can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents.

[0239] 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.

[0240] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0241] 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.

[0242] 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).

[0243] 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.

[0244] 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).

[0245] According to the method of forming a resist pattern according to the embodiment of the present invention described above, the resist composition described above is used, thereby enabling the formation of a resist pattern that has high sensitivity and is excellent in lithography properties such as resolution and roughness.

[0246] 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).

[0247] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0248] Using compounds corresponding to the structural units (monomer units) [M-1] to [M-10] shown below, polymer compounds (A)-1 to (A)-10 and (A)-X1 to (A)-X4 were synthesized in the composition ratios shown in Table 1. １３ The copolymer composition ratio of the polymer compound (the proportion (molar ratio) of each structural unit in the polymer compound) determined by C-NMR and the weight average molecular weight (Mw) calculated in terms of standard polystyrene determined by GPC measurement are also shown in Table 1.

[0249]

[0250]

[0251]

[0252]

[0253]

[0254] <Preparation of Resist Composition> The components shown in Table 1 were mixed and dissolved in solvent S-1 to prepare the resist compositions of each example. S-1: A mixed solvent of 1,570 parts by weight of propylene glycol monomethyl ether acetate, 570 parts by weight of propylene glycol monomethyl ether, and 710 parts by weight of cyclohexanone

[0255]

[0256]

[0257]

[0258] In Tables 2 to 4, the abbreviations have the following meanings: A-1 to A-10: the above polymer compounds (A)-1 to (A)-10; A-X1 to A-X4: the above polymer compounds (A)-X1 to (A)-X4; B-1 to B-4: acid generators comprising compounds represented by the following chemical formulas (B)-1 to (B)-4; D-1 to D-6: acid diffusion controllers comprising compounds represented by the following chemical formulas (D)-1 to (D)-6; F-1: hydrophobic resin F-1 containing the following structural unit (composition ratio (molar ratio): l / m=80 / 20, Mw: 25,000, Mw / Mn: 1.5).

[0259]

[0260]

[0261]

[0262] <Formation of Resist Pattern> An organic antireflective coating composition "SOC110D" (manufactured by Brewer Science) was applied to a 12-inch silicon wafer using a spinner, and then baked on a hot plate at 205°C for 60 seconds to dry, thereby forming an organic antireflective coating with a thickness of 137 nm. Furthermore, a hard mask "HM825" (manufactured by Brewer Science) was applied to the antireflective coating using a spinner, and then baked on a hot plate at 205°C for 60 seconds to dry, thereby forming a hard mask layer with a thickness of 30 nm.

[0263] The resist composition was applied to the base substrate using a spinner, prebaked (PAB) on a hot plate at 90°C for 60 seconds, and then dried to form a 75 nm thick resist film. Using an XT1900Gi ArF immersion exposure system [manufactured by ASML; NA (numerical aperture) = 1.35, Dipole 35X, Sigma (Ont 0.983, In 0.898) Y-pol, immersion medium: ultrapure water], the resist film was selectively irradiated with an ArF excimer laser (193 nm) through a photomask (6% halftone). Thereafter, a PEB treatment was performed at 90°C for 60 seconds. Next, alkaline development was performed for 18.5 seconds using a 2.38% by weight aqueous TMAH solution (trade name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23°C, followed by a 15-second rinse with pure water and subsequent drying. As a result, in all examples, a 1:1 line and space pattern (hereinafter referred to as an LS pattern) with a line dimension of 37 nm and a pitch of 74 nm was formed.

[0264] <Evaluation of Resist Pattern> [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. "3σ" refers to triple 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 critical dimension SEM (scanning electron microscope, accelerating voltage 500 V, product name: CG5000, manufactured by Hitachi High-Technologies Corporation). The results are shown in Tables 2 to 4. The smaller the 3σ value, the smaller the line width roughness, meaning that an LS pattern with a more uniform width was obtained.

[0265] [Evaluation of Sensitivity (Optimum Exposure Dose)] The optimum exposure dose at which an LS pattern of the target size is formed by the above resist pattern formation method is the sensitivity (unit: mJ / cm ２ ) was calculated and the sensitivity is shown in Tables 2 to 4.

[0266] The results shown in Tables 2 to 4 confirm that the resist compositions of Examples 1 to 19 achieved high sensitivity and formed resist patterns with excellent lithography properties.

[0267] According to the present invention, it is possible to provide a resist composition that enables high sensitivity and the formation of a resist pattern that exhibits excellent lithography properties, and a method of forming a resist pattern that uses the resist composition.

[0268] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-114247) filed on July 17, 2024, the contents of which are incorporated herein by reference.

Claims

1. A resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, comprising a base component (A) whose solubility in a developer changes due to the action of the acid, an acid generator component (B) that generates an acid upon exposure, and a fluorine additive component (F), wherein the base component (A) comprises a structural unit (a1) represented by the following general formula (a1-1), and a lactone-containing cyclic group, —SO ２ A resist composition comprising a polymeric compound (A1) having a structural unit (a2) that contains either a -containing cyclic group or a carbonate-containing cyclic group. In general formula (a1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １１ represents a cyclic hydrocarbon group having 5 to 8 carbon atoms, and n represents an integer of 1 to 3. In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 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, a carbonate-containing cyclic group, or —SO ２ represents a -containing cyclic group.] 2. The Ra in the general formula (a2-1) ２１ The resist composition according to claim 1, wherein: is a substituent represented by any one of the following formulas (a2-r-1) to (a2-r-7): [In formulas (a2-r-1) to (a2-r-7), Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ 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.

3. The resist composition according to claim 1 or 2, wherein the fluorine additive component (F) comprises a polymer having a structural unit (f1) represented by the following general formula (f1-1): In general formula (f1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 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 represents an organic group containing a fluorine atom.] 4. The resist composition according to claim 1 or 2, further comprising an acid diffusion controller component (D) that controls the diffusion of the acid generated from the acid generator component (B) upon exposure.

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

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