Resist composition and method for forming resist pattern

Abstract

The present invention relates to a resist composition in which an acid is generated by exposure and solubility in a developer is changed by the action of the acid. The resist composition comprises: a base material component (A) of which the solubility in a developer changes due to the action of an acid; and an acid generator component (B) that generates an acid by exposure. The acid generator component (B) includes a compound (B1) represented by formula (b1), a compound (B2) represented by formula (b2), and a compound (B3) represented by formula (b3) in the description.

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, the resist film is selectively exposed to light, and a development process is performed to form a resist pattern of a predetermined shape in the resist film. A resist material that changes the exposed portion of the resist film so that it dissolves in a developer is called a positive-type resist, and a resist material that changes the exposed portion so that it does not dissolve in a developer is called a negative-type resist.

[0003] In recent years, advances in lithography technology have led to rapid progress in miniaturization of patterns in the manufacture of semiconductor devices and liquid crystal display devices. A common method for miniaturization is to shorten the wavelength (increase the energy) of the exposure light source. Specifically, while ultraviolet rays such as g-line and i-line have traditionally been used, mass production of semiconductor devices using KrF excimer lasers and ArF excimer lasers has now begun. Furthermore, studies are also being conducted on EUV (extreme ultraviolet), EB (electron beam), X-rays, and other light sources with shorter wavelengths (higher energies) than excimer lasers.

[0004] In this situation, resist materials are required to have lithography properties such as sensitivity to these exposure light sources or energy sources, resolution capable of reproducing fine-dimensional patterns, etc. To satisfy these requirements, a chemically amplified resist composition containing an acid generator component that generates acid upon exposure and a base component whose solubility in a developer is changed by the action of acid has been used.

[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 for forming a resist pattern that can achieve high sensitivity, excellent lithography properties, and the formation of a resist pattern with a good shape. Patent Document 1 also describes a resist composition that employs a polymer compound containing multiple structural units with a specific structure, thereby improving dissociation performance against acid.

[0006] Japanese Patent Application Publication No. 2020-098250

[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] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that by configuring as follows, it is possible to obtain a resist composition and a method of forming a resist pattern that enable high sensitivity and the formation of a resist pattern that exhibits excellent lithography properties, and thus completed the present invention.

[0010] That is, the present invention is as follows.

[0011] [1] 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; and an acid generator component (B) that generates an acid upon exposure, wherein the acid generator component (B) has a compound (B1) represented by the following formula (b1), a compound (B2) represented by the following formula (b2), and a compound (B3) represented by the following formula (b3):

[0012]

[0013] [In the formula, R １ each independently represents a fluorinated alkyl group or a fluorinated cycloalkyl group, or at least two R １ can be linked to form a fluorinated alkylene group. １ may be the same or different. ２ and R ３ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the formula, the group adjacent to the S atom is —CH ２ m is an integer of 1 or more, and M ｍ＋ is an m-valent onium cation.] [2] The resist composition according to [1], wherein the compound (B1) represented by formula (b1) is a compound represented by the following formula (b1-1):

[0014]

[0015] [In the formula, R １’ are each independently -(CF ２ ) ｎ -, and n is an integer from 1 to 4. １’’ are each independently a fluorinated alkyl group which may have a fluorine atom or a hydrogen atom. １’ , R １’’ may be the same or different, m is an integer of 1 or more, and M ｍ＋ is an m-valent onium cation.] [3] R in formula (b2) ２ is adjacent to the S atom２ [4] The resist composition according to [1] or [2], wherein the base component (A) is a chain alkyl group having 1 to 4 carbon atoms containing a lactone-containing cyclic group, —SO , which may have a substituent, and the optional substituent is an oxo group, an alkyl group, a cyclic group, an ether bond, an ester bond, or a combination thereof. ２

[0016] The resist composition according to any one of [1] to [3], which has a structural unit containing either a -containing cyclic group or a carbonate-containing cyclic group. [5] The resist composition according to any one of [1] to [4], which further contains a fluorine-containing additive (F). [6] A method of forming a resist pattern, comprising the steps of: forming a resist film on a support using the resist composition according to any one of [1] to [5], exposing the resist film to light, and developing the exposed resist film.

[0016] The present invention is able 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.

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the preferred embodiments of the present invention, but the present invention is not limited to the following preferred embodiments.

[0018] 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 phrases "may have a substituent" or "may have a substituent" refer to the case in which a hydrogen atom (-H) is replaced with a monovalent group and the case in which a methylene group (-CH ２ -) with a divalent group. "Exposure" is a concept that includes all types of radiation exposure. "Structural unit derived from an acrylate ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylate ester. "Acrylic acid ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylate ester. ２ It is a compound in which the hydrogen atom at the terminal carboxyl group of methyl methyl ether (=CH-COOH) is substituted with an organic group.

[0019] In the acrylic acid ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. α０ ) is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms. α０ ) is substituted with a substituent containing an ester bond, or α０The term 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 obtained by modifying the hydroxyl group of the acrylic ester. Unless otherwise specified, the carbon atom at the α-position of an acrylic ester refers to the carbon atom to which the carbonyl group of 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." 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, neopentyl, etc.). 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 "alkyl group as the substituent at the α-position" are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. Specific examples of the hydroxyalkyl group as the substituent at the α-position include groups in which some or all of the hydrogen atoms of the aforementioned "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 ​​written before and after "to" as the lower and upper limits. Furthermore, in the present disclosure, when multiple substances corresponding to each component are present in the composition, the amount of each component refers to the total amount of the multiple corresponding substances present in the composition, unless otherwise specified. Furthermore, chemical structural formulas in the present disclosure may be described as simplified structural formulas in which hydrogen atoms are omitted. In the present disclosure, depending on the structure represented by the chemical formula, asymmetric carbons may be present, and enantiomers or diastereoisomers may exist. In such cases, a single chemical formula represents these isomers. These isomers may be used alone or as a mixture. In the present disclosure, "mass %" and "wt %" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

[0021] [Resist Composition] A resist composition according to an embodiment 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, and contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of the acid, and an acid generator component (B) (hereinafter also referred to as "component (B)") that generates an acid upon exposure, and the acid generator component (B) contains a compound (B1) represented by formula (b1), a compound (B2) represented by formula (b2), and a compound (B3) represented by formula (b3).

[0022]

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

[0023] In the present disclosure, a resist composition that forms a positive resist pattern by dissolving and removing exposed portions of the 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 the resist film is referred to as a negative resist composition.

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

[0025] The resist composition of this embodiment is a resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, and contains a base component (A) whose solubility in a developer changes due to the action of the acid, and an acid generator component (B) that generates an acid upon exposure.

[0026] 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 (A1) 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 copolymer having a structural unit that generates an acid upon exposure can be used. Examples of the structural unit that generates an acid upon exposure include known ones.

[0027] The resist composition of this embodiment has improved sensitivity and roughness performance because the acid generator component (B) contains three salts: the compound (B1) represented by the formula (b1), the compound (B2) represented by the formula (b2), and the compound (B3) represented by the formula (b3). The compound (B1) represented by the formula (b1) in the acid generator component (B) is a salt containing a methide of a specific structure, which contributes to high sensitivity as a photoacid generator (PAG) with high acid strength and high deprotection performance. Furthermore, the compound (B2) represented by the formula (b2) in the acid generator component (B) is a salt containing a sulfonic acid of a specific structure, which allows adjustment of the acid strength, thereby contributing to high sensitivity and improved roughness performance by achieving both deprotection performance in exposed areas and acid diffusion suppression performance in unexposed areas. Furthermore, the compound (B3) contained in the acid generator component (B) and represented by formula (b3) is a salt with a carboxylic acid, and therefore contributes to improving roughness performance as a photodecomposable base (PDB) that suppresses acid diffusion. Therefore, it is presumed that the resist composition of this embodiment improves sensitivity and roughness performance.

[0028] <Component (A)> In the resist composition of this embodiment, the component (A) is a base component whose solubility in a developer changes under the action of an acid. The component (A) 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 component (A), the polarity of the base component changes before and after exposure, and therefore good development contrast can be obtained not only in an alkaline development process but also in a solvent development process.

[0029]

[0013] When an alkaline development process is applied, the component (A) is poorly soluble in an alkaline developer before exposure, and when an acid is generated from the component (B) upon exposure, the polarity of the base component (A) increases due to the action of the acid, thereby increasing its solubility in an alkaline developer. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the exposed areas of the resist film change from being poorly soluble in an alkaline developer to being soluble, while the unexposed areas of the resist film remain poorly soluble in alkali, and therefore a positive resist pattern is formed by alkaline development.

[0030] On the other hand, when a solvent development process is applied, component (A) is highly soluble in organic developers before exposure, and when an acid is generated from component (B) upon exposure, the polarity of base component (A) increases due to the action of the acid, thereby reducing its solubility in organic developers. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed to light, the exposed areas of the resist film change from soluble to sparingly soluble in organic developers, while the unexposed areas of the resist film remain soluble. Therefore, by developing the resist with an organic developer, a contrast can be created between the exposed and unexposed areas, and a negative resist pattern can be formed.

[0031] In the resist composition of this embodiment, the component (A) may be used alone, or two or more types may be used in combination. The component (A) is a lactone-containing cyclic group, —SO ２ The polymeric compound (A1) may contain a structural unit containing either a -containing cyclic group or a carbonate-containing cyclic group.

[0032] Regarding the Component (A1): In the resist composition according to an embodiment of the present invention, the component (A) is a cyclic group containing a lactone, —SO ２ The polymeric compound (A1) may include a polymeric compound (A1) having a structural unit (a1) containing a -containing cyclic group or a carbonate-containing cyclic group.

[0033] (Structural Unit (a1)) The lactone-containing cyclic group of the structural unit (a1), —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 (a1) 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, etc.

[0034] 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.

[0035] The lactone-containing cyclic group in the structural unit (a1) is not particularly limited and any suitable group can be used. Specific examples include groups represented by the following general formulas (a1-1-1) to (a1-1-7).

[0036]

[0037] [In the formula, Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, 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.

[0038] In the general formulae (a1-1-1) to (a1-1-7), Ra' ２１The alkyl group in the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Of these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred.

[0039] 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 group include a group in which the alkyl groups mentioned above are linked to an oxygen atom (—O—).

[0040] Ra' 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.

[0041] 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 ２ -containing cyclic group.

[0042] The alkyl group for R" may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R" is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group.

[0043] 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, tricyclo[5.2.1.02,6]decane, or tetracyclododecane.

[0044] Examples of the lactone-containing cyclic group for R" include the same groups as those represented by the general formulae (a1-1-1) to (a1-1-7). Examples of the carbonate-containing cyclic group for R" include the same carbonate-containing cyclic groups described below, and specific examples include the groups represented by the general formulae (a1-3-1) to (a1-3-3).

[0045] -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 (a1-2-1) to (a1-2-4). 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.

[0046] In the general formulae (a1-1-2), (a1-1-3), and (a1-1-5), 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.

[0047] Specific examples of groups represented by general formulae (a1-1-1) to (a1-1-7) and other lactone-containing cyclic groups are listed below, where * represents a bond.

[0048]

[0049]

[0050] "-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 Preferably, the -O-S- in - is a cyclic group containing a sultone ring forming part of the ring skeleton.

[0051] -SO ２ More specific examples of the -containing cyclic group include groups represented by the following general formulae (a1-2-1) to (a1-2-4).

[0052]

[0053] [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. * represents a bond.

[0054] In the general formulae (a1-2-1) and (a1-2-2), A" is the same as A" in the general formulae (a1-1-2), (a1-1-3) and (a1-1-5).

[0055] Ra' ５１ The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″ and hydroxyalkyl group in the general formulae (a1-1-1) to (a1-1-7) are each selected from the group consisting of Ra′ ２１ Examples of the above include those mentioned in the explanation of the above.

[0056] Specific examples of the groups represented by general formulas (a1-2-1) to (a1-2-4) are listed below. In the formulas, "Ac" represents an acetyl group. * represents a bond.

[0057]

[0058]

[0059]

[0060] The term "carbonate-containing cyclic group" refers to a cyclic group that contains 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 further 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.

[0061] The carbonate ring-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following general formulae (a1-3-1) to (a1-3-3).

[0062]

[0063] [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. * represents a bond.

[0064] In the general formulae (a1-3-2) to (a1-3-3), A" is the same as A" in the general formulae (a1-1-2), (a1-1-3) and (a1-1-5).

[0065] Ra' ３１ The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″ and hydroxyalkyl group in the general formulae (a1-1-1) to (a1-1-7) are each selected from the group consisting of Ra′ ２１ Examples of the above include those mentioned in the explanation of the above.

[0066] Specific examples of the groups represented by general formulae (a1-3-1) to (a1-3-3) are listed below, where * represents a bond.

[0067]

[0068] Of the structural units (a1), structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent are particularly preferred.

[0069] The structural unit (a1) is preferably a structural unit represented by the following general formula (a1-1).

[0070]

[0071] [In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１ represents a single bond or a divalent linking group. ２１ represents -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. ２１ When is -O-, Ya ２１ does not become -CO-. ２１ is a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ -containing cyclic group.]

[0072] In the 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.

[0073] In the formula (a1-1), 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.

[0074] 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.

[0075] Ra 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 (a1-1-1) to (a1-1-7), (a1-2-1) to (a1-2-4), and (a1-3-1) to (a1-3-3), respectively.

[0076] Among these, lactone-containing cyclic groups or -SO ２ -containing cyclic groups are preferred, with groups represented by the aforementioned general formulas (a1-1-1), (a1-1-2), (a1-1-6), or (a1-2-1) being more preferred. Specifically, any of the groups represented by the aforementioned chemical formulas (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) are more preferred. The structural unit (a1) contained in the component (A1) may be of one type, or may be of two or more types.

[0077] When the component (A1) contains the structural unit (a1), the proportion of the structural unit (a1) relative to the total (100 mol %) of all structural units constituting the component (A1) is preferably 5 to 60 mol %, more preferably 10 to 60 mol %, even more preferably 20 to 55 mol %, and particularly preferably 30 to 50 mol %.

[0078] When the proportion of the structural unit (a1) is at least as great as the preferred lower limit, the effects achieved by including the structural unit (a1) can be fully obtained due to the effects described above. When the proportion of the structural unit (a1) is at most the upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0079] (Structural Unit (a2)) In addition to the structural unit (a1), the component (A1) may further include a structural unit (a2) (excluding those that fall under the category of structural unit (a1)) that includes a polar group-containing aliphatic hydrocarbon group. When the component (A1) includes the structural unit (a2), the hydrophilicity of the component (A) is enhanced, contributing to improved resolution. In addition, the acid diffusion length can be appropriately adjusted.

[0080] 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.

[0081] 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.

[0082] 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, tricyclo[5.2.1.02,6]decane, 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.

[0083] The structural unit (a2) is not particularly limited, and any structural unit can be used as long as it contains a polar group-containing aliphatic hydrocarbon group. The structural unit (a2) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, 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, the structural unit (a2) is preferably a structural unit derived from a hydroxyethyl ester of acrylic acid.

[0084] Furthermore, when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a polycyclic group, preferred examples of the structural unit (a2) include structural units represented by the following formulas (a2-1), (a2-2), and (a2-3); and when the hydrocarbon group is a monocyclic group, preferred examples of the structural unit (a2) include structural units represented by formula (a2-4).

[0085]

[0086] [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.]

[0087] In formula (a2-1), j is preferably 1 or 2, and more preferably 1. When j is 2, the hydroxyl groups are 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 it is particularly preferable that the hydroxyl group is bonded to the 3rd position of the adamantyl group.

[0088] In formula (a2-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group. In formula (a2-3), 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 5th or 6th position of the norbornyl group.

[0089] In formula (a2-4), t' is preferably 1 or 2. 1 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. The structural unit (a2) contained in the component (A1) may be one type, or two or more types. When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) 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).

[0090] By ensuring that the proportion of the structural unit (a2) is at least as great as the preferred lower limit, the effects achieved by including the structural unit (a2) can be fully obtained due to the effects described above. By ensuring that the proportion of the structural unit (a2) is at most the preferred upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0091] (Structural Unit (a3)) The polymeric compound (A1) may further include a structural unit (a3) ​​represented by the following general formula (a-3).

[0092]

[0093] In general formula (a-3), 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. ３ represents a divalent hydrocarbon group which may have an ether bond. ａ３ represents an integer of 0 to 2. ３ represents an acid-dissociable group having an alicyclic hydrocarbon group.]

[0094] The structural unit (a3) ​​is an acid-decomposable group whose polarity increases under the action of acid, and is a structural unit containing an acid-decomposable group having an alicyclic hydrocarbon group (excluding those corresponding to the structural units (a1) and (a2)). An "acid-decomposable group" is a group that has acid decomposability such that at least some of the bonds in the structure of the acid-decomposable group can be cleaved by the action of acid. Examples of acid-decomposable groups whose polarity increases under the action of acid include groups that decompose under the action of acid to produce a polar group.

[0095] 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).

[0096] Here, the term "acid-dissociable group" refers to either (i) a group having acid dissociability such that the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a portion of the bond is cleaved by the action of an acid, and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group.

[0097] The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group, and thus, when the acid-dissociable group dissociates due to the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, thereby increasing polarity.As a result, the polarity of the entire component (A1) increases.The increase in polarity relatively changes the solubility in the developer, increasing solubility when the developer is an alkaline developer and decreasing solubility when the developer is an organic developer.

[0098] The structural unit (a3) ​​contains an acid-decomposable group having an alicyclic hydrocarbon group, preferably contains an acid-decomposable group having a monocyclic alicyclic hydrocarbon group, and more preferably contains an acid-dissociable group having a monocyclic alicyclic hydrocarbon group.

[0099] The acid-decomposable group (acid-dissociable group) in the structural unit (a3) ​​has an appropriate bulkiness, which allows for appropriate adjustment of acid diffusion control and developer solubility, thereby reducing roughness when forming a resist pattern. Examples of the acid-dissociable group in the structural unit (a3) ​​include those that have been proposed as acid-dissociable groups for base resins for chemically amplified resists. Specific examples of acid-dissociable groups that have been proposed as base resins for chemically amplified resists include "acetal-type acid-dissociable groups" and "tertiary alkyl ester-type acid-dissociable groups," which are described below.

[0100] Acetal-Type Acid-Dissociable Group: Examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group among the polar groups include an acid-dissociable group represented by the following formula (a3-r-1) (hereinafter, sometimes referred to as an "acetal-type acid-dissociable group").

[0101]

[0102] [In formula (a3-r-1), Ra' ０１ , Ra' ０２ represents a hydrogen atom or an alkyl group. ０３ is an alicyclic hydrocarbon group, and Ra' ０３ is Ra' ０１ , Ra' ０２may be bonded to any one of the following to form a ring.]

[0103] In formula (a3-r-1), Ra' ０１ and Ra' ０２ Among Ra', at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. ０１ or Ra' ０２ When is an alkyl group, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester, and an alkyl group having 1 to 5 carbon atoms is preferred. Specific examples include linear or branched alkyl groups. More specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. A methyl group or an ethyl group is more preferred, and a methyl group is particularly preferred.

[0104] In formula (a3-r-1), Ra' ０３ The alicyclic hydrocarbon group represented by may be a polycyclic group or a monocyclic group, and is preferably a monocyclic group.

[0105] The monocyclic alicyclic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane.

[0106] The alicyclic hydrocarbon group, which is a polycyclic group, is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane, and tetracyclododecane. ０３ The alicyclic hydrocarbon group in may have a substituent. Examples of the substituent include -R Ｐ１ , -R Ｐ２ -O-R Ｐ１ , -R Ｐ２ -CO-R Ｐ１ , -RＰ２ -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 ") are also examples.

[0107] Here, R Ｐ１ is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ２ is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Ｐ１ and R Ｐ２ Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the aliphatic cyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic hydrocarbon group may have one or more of one type of the substituents, or may have one or more of each of multiple types of the substituents.

[0108] 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. Ra' ０３ But Ra' ０１ , Ra' ０２When the alicyclic hydrocarbon group is bonded to any of the above to form a monocyclic ring (a ring in which some of the carbon atoms of a monocyclic alicyclic hydrocarbon are substituted with oxygen atoms), the monocyclic ring is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the monocyclic cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0109] Tertiary alkyl ester-type acid-dissociable group: Among the polar groups, examples of the acid-dissociable group protecting the carboxy group include acid-dissociable groups represented by the following formula (a3-r-2). Among the acid-dissociable groups represented by the following formula (a3-r-2), Ra' ０４ ~Ra' ０６ and each represent an alkyl group, the group may be referred to as a "tertiary alkyl ester-type acid-dissociable group" for convenience.

[0110]

[0111] [In formula (a3-r-2), Ra' ０４ ~Ra' ０６ are each a hydrocarbon group, and Ra' ０４ ~Ra' ０６ At least one of Ra' is an alicyclic hydrocarbon group, or ０５ , Ra' ０６ are bonded to each other to form an alicyclic hydrocarbon group.

[0112] Ra' ０４ ~Ra' ０６ Examples of the hydrocarbon group of Ra' include a linear or branched alkyl group, a linear or cyclic alkenyl group, and a cyclic hydrocarbon group. ０４ ~Ra' ０６ At least one of Ra' is an alicyclic hydrocarbon group, or ０５ , Ra' ０６ are bonded to each other to form an alicyclic hydrocarbon group.

[0113] The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0114] The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0115] Ra' ０４ ~Ra' ０６ When either of the above is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane.

[0116] Ra' ０４ ~Ra' ０６ When any of the above is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms.

[0117] Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a portion of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

[0118] Specific examples of the aromatic hydrocarbon group include groups in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl groups or heteroaryl groups); groups in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0119] The cyclic hydrocarbon group may have a substituent. Examples of the substituent include Ra' in the formula (a3-r-1). ０３ The substituents that may be contained in the alicyclic hydrocarbon group in Ra′ are the same as those that may be contained in the alicyclic hydrocarbon group in Ra′. ０５ and Ra' ０６ and (a3-r2-3) are bonded to each other to form a ring. Suitable examples of the acid-dissociable group include groups represented by the following formulas (a3-r2-1), (a3-r2-2), and (a3-r2-3):

[0120] On the other hand, Ra' ０４ ~Ra' ０６ When the groups are not bonded to each other but are independent hydrocarbon groups, examples of the acid-dissociable group include groups represented by the following formula (a3-r2-4): In the following formula, * represents a bond.

[0121]

[0122] [In formula (a3-r2-1), Rax' １０ represents an alkyl group having 1 to 10 carbon atoms. １１ is Rax' １０ represents a group which forms an alicyclic hydrocarbon group together with the carbon atom to which it is bonded. In formula (a3-r2-2), Yax is a carbon atom. Xax is a group which forms an alicyclic hydrocarbon group together with Yax. Some or all of the hydrogen atoms in this alicyclic hydrocarbon group may be substituted. Rax ０１ ~Rax ０３ are each independently a hydrogen atom, a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms in the linear saturated hydrocarbon group and the aliphatic cyclic saturated hydrocarbon group may be substituted. ０１ ~Rax ０３ Two or more of the above may be bonded to each other to form a cyclic structure. In formula (a3-r2-3), Yab is a carbon atom. Xab is a group that forms an alicyclic hydrocarbon group together with Yab. Rax ０４ In formula (a3-r2-4), Rax' is an aromatic hydrocarbon group which may have a substituent. １２ and Rax' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted. １４ is an alicyclic hydrocarbon group. * indicates a bond (the same applies hereinafter).

[0123] In the formula (a3-r2-1), Rax' １０ The alkyl group having 1 to 10 carbon atoms in the formula (I) may be a straight-chain or branched-chain alkyl group.

[0124] The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and the like, with a methyl group or an ethyl group being preferred. The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0125] Rax' in the formula (a3-r2-1) １０ Among the above, R ax′ is preferably a linear alkyl group having 1 to 5 carbon atoms, and specifically, a methyl group or an ethyl group is preferable. １１ (Rax' １０ The alicyclic group (which forms an alicyclic hydrocarbon together with the carbon atom to which it is bonded) is preferably a monocyclic alicyclic hydrocarbon group, and examples thereof include groups in which two or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms, and even more preferably 3 to 6 carbon atoms. Specific examples thereof include cyclopentane and cyclohexane.

[0126] In the formula (a3-r2-2), the alicyclic hydrocarbon group formed by Xax together with Yax is preferably a monocyclic alicyclic hydrocarbon group, and in the formula (a3-r2-1), Rax' １１ In the formula (a3-r2-2), Rax ０１ ~Rax ０３ In the formula (I), examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group.

[0127] Rax ０１ ~Rax ０３In the formula (R ax ), examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group. ０１ ~Rax ０３ Among the above, from the viewpoint of ease of synthesis of the monomer compound, is preferably a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferred, and a hydrogen atom is particularly preferred.

[0128] The Rax ０１ ~Rax ０３ Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula: ０５ The same groups as those shown below can be mentioned. ０１ ~Rax ０３ Examples of the group containing a carbon-carbon double bond formed when two or more of the above are bonded to each other to form a cyclic structure include a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclohexenyl group, a cyclopentylidene-ethenyl group, and a cyclohexylidene-ethenyl group. Among these, from the viewpoint of ease of synthesis of the monomer compound, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred. In formula (a3-r2-3), the alicyclic hydrocarbon group formed by Xab together with Yab is preferably a monocyclic alicyclic hydrocarbon group, and in formula (a3-r2-1), Rax' １１ This is the same as the content explained in

[0129] In formula (a3-r2-3), Rax ０４ Examples of the aromatic hydrocarbon group in the formula (I) include groups in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 5 to 30 carbon atoms. ０４is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from benzene or naphthalene, and most preferably a group in which one or more hydrogen atoms have been removed from benzene.

[0130] Rax in formula (a3-r2-3) ０４ Examples of the substituent that may be possessed by the group include a methyl group, an ethyl group, a propyl group, a hydroxy group, a carboxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkoxy group (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc.), an alkyloxycarbonyl group, and the like.

[0131] In formula (a3-r2-4), Rax' １２ and Rax' １３ are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. １２ and Rax' １３ In the formula (I), the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Rax ０１ ~Rax ０３ Examples include the same monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms as in the above. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted.

[0132] Rax' １２ and Rax' １３ Among these, R ax′ is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group or an ethyl group. １２ and Rax' １３ In the case where the chain saturated hydrocarbon group represented by the formula: ０５ The same groups as those shown below can be mentioned.

[0133] In formula (a3-r2-4), Rax' １４is an alicyclic hydrocarbon group, and is preferably a monocyclic alicyclic hydrocarbon group which may have a substituent. １４ Examples of the alicyclic hydrocarbon group in include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms, and even more preferably 3 to 6 carbon atoms. Specific examples of suitable monocycloalkanes include cyclopentane and cyclohexane.

[0134] Rax' １４ The substituents that may be possessed by Rax ０４ Specific examples of the group represented by formula (a3-r2-1) are listed below. In the following formulas, * represents a bond.

[0135]

[0136]

[0137] Specific examples of the group represented by the formula (a3-r2-2) are listed below: In the following formula, * represents a bond.

[0138]

[0139]

[0140]

[0141] Specific examples of the group represented by the formula (a3-r2-3) are listed below: In the following formula, * represents a bond.

[0142]

[0143] Specific examples of the group represented by the formula (a3-r2-4) are listed below: In the following formula, * represents a bond.

[0144]

[0145] Tertiary alkyloxycarbonyl acid-dissociable group: Examples of the acid-dissociable group that protects the hydroxyl group of the polar group include an acid-dissociable group represented by the following formula (a3-r-3) (hereinafter, for convenience, may be referred to as a "tertiary alkyloxycarbonyl acid-dissociable group").

[0146]

[0147] [In the formula, Ra' ７ ~Ra' ９ and each represent an alkyl group.] In formula (a3-r-3), Ra' ７ ~Ra' ９ are each preferably an alkyl group having 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms. The total number of carbon atoms in the alkyl groups is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4. Of the above, the structural unit (a3) ​​preferably includes those having Ra ３ is preferably an acid-dissociable group represented by the above formula (a3-r-1) or (a3-r-3). Specific examples of the structural unit (a3) ​​represented by the above general formula (a-3) are shown below. In the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158] The structural unit (a3) ​​that the component (A1) may have may be of one type, or may be of two or more types.

[0159] Within the component (A1), the proportion of the structural unit (a3) ​​is preferably 20 to 85 mol %, more preferably 30 to 80 mol %, and particularly preferably 35 to 70 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 or above the preferred lower limit described above, lithography properties such as resolution and roughness improvement are improved. Furthermore, by ensuring that the proportion of the structural unit (a3) ​​is at or below the upper limit of the preferred range described above, a balance with the other structural units can be achieved, resulting in various favorable lithography properties.

[0160] <<Other Structural Units>> The component (A1) may contain other structural units in addition to the aforementioned structural units (a1), (a2), and (a3). Examples of other structural units include the structural unit (a4) containing an acid-decomposable group whose polarity increases under the action of acid, the structural unit (a5) containing a hydroxystyrene skeleton, and the structural unit (a6) containing an acid-non-dissociable aliphatic cyclic group. Many of the structural units (a4) to (a6) that are conventionally known for use in resin components of resist compositions can be used.

[0161] The resist composition may contain one type of component (A1), or two or more types of components may be used in combination.

[0162] In the resist composition of this embodiment, the resin component (A1) can comprise a polymeric compound that has the structural unit (a1), or a polymeric compound that has the structural unit (a1) and further comprises the structural unit (a2) and / or the structural unit (a3), and these polymers can be used alone, or two or more types can be used in combination.

[0163] Preferred examples of the component (A1) include polymeric compounds comprising a repeating structure of the structural unit (a1) and the structural unit (a2), polymeric compounds comprising a repeating structure of the structural unit (a1) and the structural unit (a3), polymeric compounds comprising a repeating structure of the structural unit (a1), the structural unit (a2), and the structural unit (a3), and polymeric compounds comprising a repeating structure of the structural unit (a1), the structural unit (a2), the structural unit (a3), and another structural unit.

[0164] Component (A1) can be produced by dissolving monomers from which each structural unit is derived in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing the resulting monomer. Alternatively, component (A1) can be produced by dissolving a monomer from which structural unit (a1) is derived, and optionally a monomer from which structural unit (a2) is derived, and optionally a monomer from which structural unit (a3) ​​is derived, and optionally a monomer from which a structural unit other than these is derived, in a polymerization solvent, adding a radical polymerization initiator such as those described above to the solution and polymerizing the resulting monomer, and then carrying out a deprotection reaction. During the polymerization, for example, HS-CH ２ -CH ２ -CH ２ -C(CF ３ ) ２ By using a chain transfer agent such as —OH in combination, it is possible to obtain a chain with —C(CF ３ ) 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).

[0165] 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 100,000, and more preferably 5,000 to 50,000. When the Mw of component (A1) is equal to or less than the preferred upper limit of this range, component (A1) will have sufficient solubility in a resist solvent for use as a resist, while when the Mw of component (A1) is equal to or greater than the preferred lower limit of this range, the dry etching resistance and the cross-sectional shape of the resist pattern will be excellent.

[0166] The dispersity (Mw / Mn) of component (A1) is not particularly limited, but is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.0, and particularly preferably from 1.0 to 2.0, where Mn represents the number average molecular weight.

[0167] Regarding the component (A2): The resist composition of this embodiment may also use, as the component (A), a base component (A2) (hereafter referred to as "component (A2)") that does not fall under the category of the component (A1) and whose solubility in a developer changes upon the action of acid. There are no particular limitations on the component (A2), and it may be arbitrarily selected from the many base components conventionally known for use in chemically amplified resist compositions. The component (A2) may be a polymeric compound or a low molecular weight compound, and may be used either alone or in combination of two or more types.

[0168] The proportion of the component (A1) in 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 is excellent in various lithography properties, such as high sensitivity, resolution, and improved roughness, is more likely to be formed.

[0169] The amount of the component (A) in the resist composition of this embodiment can be adjusted depending on factors such as the thickness of the resist film to be formed. The resist composition of this embodiment must also contain, in addition to the component (A), an acid generator component (B) that generates acid upon exposure (hereafter also referred to as "component (B)").

[0170] <Component (B)> In this embodiment, the acid generator component (B) includes a compound (B1) represented by the following formula (b1), a compound (B2) represented by the following formula (b2), and a compound (B3) represented by the following formula (b3):

[0171]

[0172] [In the formula, R １ each independently represents a fluorinated alkyl group or a fluorinated cycloalkyl group, or at least two R １ can be linked to form a fluorinated alkylene group. １ may be the same or different. ２ and R ３ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the formula, the group adjacent to the S atom is —CH ２ m is an integer of 1 or more, and M ｍ＋ is an m-valent onium cation.

[0173] [Anion moiety] Anion of component (B1) In formula (b1), R １ each independently represents a fluorinated alkyl group or a fluorinated cycloalkyl group, or at least two R １ can be linked to form a fluorinated alkylene group.

[0174] R １ The fluorinated alkyl group of R may be a linear or branched fluorinated alkyl group, and preferably has 1 to 8 carbon atoms. １ The fluorinated cycloalkyl group preferably has 3 to 8 carbon atoms. １ The fluorinated alkylene group formed by bonding of R preferably has 2 to 8 carbon atoms. １Examples of the fluorinated alkyl group having 1 to 8 carbon atoms include perfluoro or partially fluorinated alkyl groups, such as trifluoromethyl, pentafluoroethyl, heptafluoro-n-butyl, heptafluoro-i-propyl, nonafluoro-n-butyl, nonafluoro-2-methylpropyl, nonafluoro-1-methylpropyl, nonafluoro-t-butyl, perfluoro-n-pentyl, perfluoroneopentyl, perfluoro-n-hexyl, perfluoro-n-heptyl, and perfluoro-n-octyl groups.

[0175] Two R's １ Specific examples of the fluorinated alkylene group having 2 to 8 carbon atoms bonded to R include perfluoro or partially fluorinated alkylene groups, such as tetrafluoroethylene, 1,2-hexafluoropropylene, 1,3-hexafluoropropylene, 1,2-octafluorobutylene, 1,3-octafluorobutylene, 1,4-octafluorobutylene, 2-trifluoromethyl-1,3-pentafluoropropylene, 1,5-perfluoropentylene, 1,6-perfluorohexylene, 1,7-perfluoroheptylene, and 1,8-perfluorooctylene. １ is a perfluoroalkyl group (C ｎ F ２ｎ＋１ ) and n is an integer of 1 to 8.

[0176] The component (B1) is preferably a compound represented by the following formula (b1-1):

[0177]

[0178] [In the formula, R １’ are each independently -(CF ２ ) ｎ -, and n is an integer from 1 to 4. １’’ are each independently a fluorinated alkyl group which may have a fluorine atom or a hydrogen atom. １’ , R １’’ may be the same or different, m is an integer of 1 or more, and Mｍ＋ is an m-valent onium cation.

[0179] R １’’ The fluorinated alkyl group in R １ Examples of the anion moiety of component (B1) include the same fluorinated alkyl groups as those listed above. Specific examples of preferred anion moieties of component (B1) are listed below.

[0180]

[0181] Anion of component (B2) In formula (b2), R ２ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the formula, the group adjacent to the S atom is —CH ２ - is.

[0182] - Cyclic group optionally having a substituent: The cyclic group optionally having a substituent is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.

[0183] The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. ２ The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The number of carbon atoms in such an aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms of the substituent.

[0184] R ２ Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. ２Specific examples of the aromatic hydrocarbon group 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 number of carbon atoms in the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

[0185] R ２ Examples of the cyclic aliphatic hydrocarbon group in (1) include aliphatic hydrocarbon groups containing a ring in their structure. Examples of aliphatic hydrocarbon groups containing a ring in their structure include aliphatic cyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an aliphatic cyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and groups in which an aliphatic cyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group. The aliphatic cyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The aliphatic cyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic aliphatic cyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic aliphatic cyclic hydrocarbon group is preferably a group 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 bridged ring polycyclic skeleton such as adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton such as a cyclic group having a steroid skeleton. Among these, R ２The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, further preferably an adamantyl group or a norbornyl group, and particularly preferably an adamantyl group.

[0186] The linear aliphatic hydrocarbon group which may be bonded to the aliphatic cyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. As the linear aliphatic hydrocarbon group, a linear alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH ２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group which may be bonded to the aliphatic cyclic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, -CH(CH ３ ) -, -CH(CH ２ CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH２ -, -CH(CH ２ CH ３ ) CH ２ -, -C(CH ２ CH ３ ) ２ -CH ２ alkylethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ alkyltrimethylene groups such as -; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ The alkyl group of the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. ２ The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specifically, lactone-containing cyclic groups represented by the general formulae (a1-1-1) to (a1-1-7), —SO ２ -containing cyclic groups, and heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16), respectively, in which * represents a bond.

[0187]

[0188] R ２ Examples of the substituent on 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.

[0189] The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group is most preferred. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group is more preferred, and a methoxy group or an ethoxy group is most preferred. Examples of halogen atoms as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Examples of halogenated alkyl groups as a substituent include alkyl groups having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group, in which some or all of the hydrogen atoms have been substituted with the halogen atoms. The carbonyl group as a substituent is a methylene group (-CH ２ -) is a group that substitutes

[0190] R ２ The cyclic hydrocarbon group in may be a fused ring group containing a fused ring in which an aliphatic hydrocarbon ring and an aromatic ring are fused. Examples of the fused ring include a polycycloalkane having a bridged ring polycyclic skeleton to which one or more aromatic rings are fused. Specific examples of the bridged ring polycycloalkane include bicycloalkanes such as bicyclo[2.2.1]heptane (norbornane) and bicyclo[2.2.2]octane. The fused ring group is preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicycloalkane, and more preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicyclo[2.2.2]octane. ２ Specific examples of the fused cyclic group include those represented by the following formulae (r-br-1) to (r-br-2), in which * represents a bond.

[0191]

[0192] R ２Examples of the substituent that the fused cyclic group may have include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an aromatic hydrocarbon group, an aliphatic cyclic hydrocarbon group, etc. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group may be any of the groups described above in R ２ Examples of the aromatic hydrocarbon group as the substituent of the fused cyclic group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc.), and the heterocyclic groups represented by the formulas (r-hr-1) to (r-hr-6) above. Examples of the aliphatic cyclic hydrocarbon group as a substituent of the fused cyclic group include groups in which one hydrogen atom has been removed from a monocycloalkane such as cyclopentane or cyclohexane; groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane or tetracyclododecane; lactone-containing cyclic groups represented by the general formulae (a1-1-1) to (a1-1-7), respectively; -SO represented by the general formulae (a1-2-1) to (a1-2-4), respectively; ２ -containing cyclic group: heterocyclic groups represented by the above formulae (r-hr-7) to (r-hr-16), respectively.

[0193] A chain alkyl group which may have a substituent: R ２The chain alkyl group may be either linear or branched. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0194] A chain alkenyl group which may have a substituent: R ２ The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of linear alkenyl groups include vinyl, propenyl (allyl), and butenyl groups. Examples of branched alkenyl groups include 1-methylvinyl, 2-methylvinyl, 1-methylpropenyl, and 2-methylpropenyl groups.

[0195] Of the chain alkenyl groups listed above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred. ２ Examples of the substituent of the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the R ２ and the like.

[0196] R 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, and 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, tricyclo[5.2.1.02,6]decane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor, or the like.

[0197] R ２ The hydrocarbon group may have a substituent, and examples of the substituent 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, 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 connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by any of the following formulas (y-al-1) to (y-al-5).

[0198]

[0199] [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.

[0200] 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.

[0201] 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 CH ３ ) -, -C(CH ３ ) ２ -, -C(CH ３ ) (CH ２ CH ３ ) -, -C(CH ３ ) (CH ２ CH ２ CH ３ ) -, -C(CH ２ CH ３ ) ２ alkylmethylene groups such as -; ethylene groups [-CH ２ CH ２ -]; -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -CH(CH ２ CH ３ ) CH ２ -, etc.; a trimethylene group (n-propylene group) [—CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ an alkyltrimethylene group such as -; a tetramethylene group [-CH ２ CH ２ CH ２ CH ２ -]; -CH(CH ３ ) CH ２ CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ -, etc.; an alkyltetramethylene group such as a pentamethylene group [—CH ２ CH ２ CH ２ CH ２ CH ２-] etc.

[0202] Furthermore, 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.

[0203] Among the above, R ２ is a -CH adjacent to the S atom ２ It is a chain alkyl group having 1 to 4 carbon atoms, which contains a - group and may have a substituent, and the optional substituent is preferably an oxo group, an alkyl group, a cyclic group, an ether bond, an ester bond, or a combination thereof. Specific examples of preferred anionic moieties for component (B2) are shown below.

[0204]

[0205] Anion of component (B3) In formula (b3), R ３ 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 R ２ and (the group adjacent to the S atom is -CH ２ - (except that it is the same as above).

[0206] Among them, R ３ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group, 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 connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by any of the above formulas (y-al-1) to (y-al-5).

[0207] 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). More preferred examples of the aliphatic cyclic group include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include straight-chain alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched-chain alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0208] 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. R ３ The anion of component (B3) is preferably a fluorinated alkyl group in which some or all of the hydrogen atoms constituting the linear alkyl group have been substituted with fluorine atoms, and particularly preferably 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). Specific preferred examples of the anion of component (B3) are shown below.

[0209]

[0210] [Cation moiety: (M ｍ＋ ) １／ｍ In the formula (b1), formula (b2) and formula (b3), M ｍ＋ represents an m-valent onium cation.ｍ＋ In the formula (I), the onium cation is more preferably a sulfonium cation or an iodonium cation, and m is an integer of 1 or more.

[0211] Preferred cationic moieties ((M ｍ＋ ) １／ｍ ) includes organic cations represented by any one of the following general formulas (ca-1) to (ca-3).

[0212]

[0213] [In general formulas (ca-1) to (ca-3), R ２０１ ~R ２０７ each independently represents an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent, R 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 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; 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, and L ２０１ represents —C(═O)— or —C(═O)—O—.]

[0214] 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 the formula (I) preferably has 2 to 10 carbon atoms.

[0215] R ２０１ ~R ２０７Examples 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, an arylthio group, and a group represented by any one of the following formulae (car-r-1) to (car-r-7):

[0216] The aryl group in the arylthio group as a substituent includes an aryl group having 6 to 20 carbon atoms, and is preferably a phenyl group, a naphthyl group, or a biphenyl group. Examples of the arylthio group include a phenylthio group, a naphthylthio group, and a biphenylthio group.

[0217]

[0218] [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.

[0219] R' ２０１ The optionally substituted cyclic group represented by is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. Examples of aromatic hydrocarbon groups include aromatic hydrocarbon rings or aryl groups in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings, with phenyl and naphthyl groups being preferred. Examples of aliphatic hydrocarbon groups include groups in which one hydrogen atom has been removed from a monocycloalkane or polycycloalkane, with adamantyl and norbornyl being preferred.

[0220] R' ２０１ The optionally substituted chain alkyl group represented by may be either a straight chain or a branched chain.

[0221] The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, and a docosyl group.

[0222] R' ２０１ The optionally substituted chain alkenyl group represented by may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of linear alkenyl groups include vinyl, propenyl (allyl), and butenyl groups. Examples of branched alkenyl groups include 1-methylpropenyl and 2-methylpropenyl groups. Of the above, the propenyl group is particularly preferred as the chain alkenyl group.

[0223] R' ２０１ Examples of the optionally substituted cyclic group or optionally substituted chain alkyl group represented by R' include the same as those of the acid-dissociable group represented by formula (a3-r-2). ２０１ Examples of the substituent in the cyclic group, chain alkyl group, or chain alkenyl group represented by the formula (I) include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group.

[0224] The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, or tert-butoxy group, and most preferably a methoxy group or ethoxy group. Examples of halogen atoms as substituents include a fluorine atom, chlorine atom, bromine atom, and iodine atom, and a fluorine atom is preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl group, ethyl group, propyl group, n-butyl group, and tert-butyl group, in which some or all of the hydrogen atoms have been substituted with the halogen atoms.

[0225] 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 by heteroatoms such as sulfur atoms, oxygen atoms, and nitrogen atoms, or by 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.) As for the ring formed, one ring containing a sulfur atom in its ring skeleton in the formula is preferably a 3- to 10-membered ring including the sulfur atom, and particularly preferably a 5- to 7-membered ring. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a phenoxathiin ring, a tetrahydrothiophenium ring, a tetrahydrothiopyranium ring, and a thioxanium ring.

[0226] R ２０８ ~R ２０９ R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２０８ ~R２０９ When each of these independently represents an alkyl group, they may be bonded to each other to form a ring.

[0227] 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 is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

[0228] R ２１０ The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms.

[0229] R ２１０ -SO which may have a substituent ２ In the -containing cyclic group, "-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.

[0230] -SO 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 Preferably, the -O-S- in - is a cyclic group containing a sultone ring forming part of the ring skeleton.

[0231] R ２１０ -SO which may have a substituent ２The -containing cyclic group is preferably a group represented by the formula (a1-2-1). ２１０ The substituents that may be possessed by R ２０１ ~R ２０７ Examples of the substituents that may be possessed by the group include:

[0232] The cation represented by formula (ca-1) is preferably a cation represented by the following formula (b-2):

[0233]

[0234] In formula (b-2), Rb ２０１ ~Rb ２０２ represents an aryl group which may have a substituent, Rb ２０３ represents an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. ２０１ ~Rb ２０３ may be bonded to each other to form a ring together with the sulfur atom in formula (b-2).

[0235] Rb ２０１ ~Rb ２０２ The optionally substituted aryl group represented by R ２０１ ~R ２０７ The meanings of the aryl group which may have a substituent are the same as those of the aryl group which may have a substituent, and the preferred examples are also the same.

[0236] Rb ２０３ The optionally substituted aryl group, optionally substituted alkyl group, or optionally substituted alkenyl group represented by R ２０１ ~R ２０７ The meanings of the groups are the same as the optionally substituted aryl group, the optionally substituted alkyl group, and the optionally substituted alkenyl group, and preferred examples are also the same.

[0237] Specific examples of suitable cations represented by formula (ca-1) include cations represented by any of the following formulas (ca-1-1) to (ca-1-67).

[0238]

[0239]

[0240]

[0241] [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.]

[0242]

[0243] [In the formula, R” ２０１ is a hydrogen atom or a substituent, and the substituent is the same as R ２０１ ~R ２０７ , and R ２１０ The substituents are the same as those exemplified as the substituents that may be possessed by

[0244] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by any of the following formulas (ca-3-1) to (ca-3-6).

[0245]

[0246] In the resist composition of this embodiment, the components (B1) to (B3) may each be used alone, or two or more types may be used in combination.

[0247] In the resist composition of this embodiment, the amount of the component (B1) relative to 100 parts by mass of the component (A) is preferably 5 to 35 parts by mass, more preferably 5 to 30 parts by mass, even more preferably 5 to 25 parts by mass, and most preferably 5 to 20 parts by mass.

[0248] In the resist composition of this embodiment, the amount of the component (B2) relative to 100 parts by mass of the component (A) is preferably 1 to 20 parts by mass, more preferably 1 to 15 parts by mass, even more preferably 1 to 10 parts by mass, and most preferably 1 to 5 parts by mass.

[0249] In the resist composition of this embodiment, the amount of the component (B3) relative to 100 parts by mass of the component (A) is preferably 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 1 to 15 parts by mass.

[0250] When the contents of components (B1) to (B3) are at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity and LWR are further improved during resist pattern formation. On the other hand, when the contents are no larger than the upper limit of the aforementioned preferred range, a homogeneous solution is more easily obtained when the components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition is further improved. Components (B1) to (B3) can be produced using known methods.

[0251] Regarding Component (B4): The resist composition of this embodiment may also contain an acid generator component (hereafter referred to as "component (B4)") other than the components (B1) to (B3), as long as the effects of the present invention are not impaired. By including the component (B4) in the resist composition, the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern.

[0252] The component (B4) is not particularly limited as long as it decomposes upon exposure and loses its acid diffusion controllability, and is preferably one or more compounds selected from the group consisting of compounds represented by the following general formula (b4) (hereinafter referred to as "component (B4)"): The component (B4) decomposes and loses its acid diffusion controllability (basicity) in the exposed areas of the resist film, and therefore does not function as a quencher, but functions as a quencher in the unexposed areas of the resist film.

[0253]

[0254] [In the formula, Rd ３ and 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. 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.

[0255] Anion portion In formula (b4), 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 ２０１The fluorine atom-containing cyclic group, the fluorine atom-containing chain alkyl group, or the fluorine atom-containing chain alkenyl group is preferred.

[0256] Among these, fluorinated alkyl groups are preferred, and 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 ３ As 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.

[0257] In formula (b4), Rd ４ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and ２０１ The same can be mentioned.

[0258] Rd ４ The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. ４ A portion of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, or the like.

[0259] 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.

[0260] Rd４ The cyclic group in the formula (I) is the same as the R' ２０１ Examples of the cyclic groups include those similar to the cyclic groups in the above, and preferred are alicyclic groups in which one or more hydrogen atoms have been removed from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane, 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.

[0261] In formula (b4), 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.

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

[0263] ...Yd １ The aliphatic hydrocarbon group in the above formula (1) means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups that contain a ring in their structure.

[0264] ...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specifically, a methylene group [—CH ２ -], ethylene group [-(CH２ ) ２ -], trimethylene group [-(CH ２ ) ３ -], tetramethylene group [-(CH ２ ) ４ -], pentamethylene group [-(CH ２ ) ５ The branched aliphatic hydrocarbon group preferably has 3 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.

[0265] The branched chain aliphatic hydrocarbon group is preferably a branched chain alkylene group, 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 ２CH ２ CH ２ -, -CH ２ CH (CH ３ ) CH ２ CH ２ Examples of the alkyl group include alkyl tetramethylene groups such as -. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and a carbonyl group.

[0266] ... Aliphatic hydrocarbon groups containing a ring in their structure Examples of the aliphatic hydrocarbon groups containing a ring in their structure include cyclic aliphatic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above.

[0267] The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclo[5.2.1.02,6]decane, and tetracyclododecane.

[0268] The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

[0269] Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom. Examples of the substituent containing a heteroatom include -O-, -C(=O)-O-, -S-, and -S(=O) ２ -, -S(=O) ２ —O— is preferred.

[0270] ...Yd １The aromatic hydrocarbon group in the above formula (1) is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings.

[0271] Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl groups or heteroaryl groups), in which one hydrogen atom has been substituted with an alkylene group (e.g., groups in which one further hydrogen atom has been removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 or 2, and particularly preferably 1.

[0272] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group.

[0273] The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom, and halogenated alkyl group as the substituent include those exemplified as the substituent substituting a hydrogen atom in the cyclic aliphatic hydrocarbon group.

[0274] Divalent linking group containing a hetero atom: Yd １ is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, and -S(=O) ２ -, -S(=O) ２ —O—, —CH ２ -C(=O)-O-, -CH ２ —O—C(═O)— and the like.

[0275] Among these, from the viewpoint of solubility in a developer, —O—, —C(═O)—O—, —C(═O)—, —O—C(═O)—O—, —CH ２ -C(=O)-O-, -CH ２ -O-C(=O)- is preferred, and -CH ２ -C(=O)-O-, -CH ２ —O—C(═O)— is particularly preferred. １ Examples include a single bond, —CH ２ -C(=O)-O-, -CH ２ —O—C(═O)—, or —CH ２ - is preferred, and a single bond is more preferred. １ The anion moiety of component (B4) 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 even more preferably a methylene group or an ethylene group. Specific examples of preferred anion moieties of component (B4) are shown below.

[0276]

[0277]

[0278] Cation moiety In formula (b4), M ｍ＋ is an m-valent organic cation. ｍ＋ Suitable examples of the organic cation include the same as the cation represented by any one of the general formulas (ca-1) to (ca-3), with the cation represented by the general formula (ca-1) being more preferred, and the cation represented by any one of the general formulas (ca-1-1) to (ca-1-67) being even more preferred. One type of component (B4) may be used alone, or two or more types may be used in combination.

[0279] When the resist composition contains the component (B4), the amount of the component (B4) in the resist composition is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2.5 to 10 parts by mass, per 100 parts by mass of the component (A). When the amount of the component (B4) is at least as large as the preferred lower limit, it is easier to obtain particularly good lithography properties and a resist pattern shape. On the other hand, when the amount of the component (B4) is no more than the upper limit, it is possible to maintain good sensitivity and achieve excellent throughput.

[0280] Production method of component (B4): The production method of the component (B4) is not particularly limited, and it can be produced, for example, in the same manner as the method described in US 2012-0149916.

[0281] Regarding the Component (B5): The resist composition of this embodiment may also contain an acid generator component (hereafter referred to as “component (B5)”) other than the components (B1) to (B4), as long as the effects of the present invention are not impaired.

[0282] The component (B5) is not particularly limited, and any of the acid generators 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. In the resist composition of this embodiment, the component (B5) may be used alone, or two or more types may be used in combination. When the resist composition contains the component (B5), the amount of the component (B5) in the resist composition is preferably 50 parts by mass or less, more preferably 1 to 40 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the component (A). By ensuring that the amount of the component (B5) is within the above range, sufficient pattern formation can be achieved. Furthermore, when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is also favorable.

[0283] <Optional Components> The resist composition of this embodiment may further contain components (optional components) other than the above-described components (A) and (B). Examples of such optional components include the following components (D), (E), (F), and (S).

[0284] <Component (D)> The resist composition of this embodiment may further contain a base component (hereafter referred to as "component (D)") in addition to the components (A) and (B). The component (D) acts as a quencher (acid diffusion controller) that traps acid generated in the resist composition upon exposure. The component (D) may be a nitrogen-containing organic compound (D1) (hereafter referred to as "component (D1)").

[0285] By including the component (D) in the resist composition, the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern.

[0286] Regarding the component (D1), the component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D1)") as an acid diffusion controller. The component (D1) may be any known compound that acts as an acid diffusion controller. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are particularly preferred.

[0287] The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms. Examples of the aliphatic amine include ammonia NH ３ and cyclic amines, in which at least one hydrogen atom is substituted with an alkyl group having 12 or less carbon atoms or a hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines).

[0288] Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 6 to 30 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred. 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).

[0289] Specific examples of the aliphatic monocyclic amine include piperidine, piperazine, etc. Specific examples of the aliphatic polycyclic amine 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.

[0290] 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.

[0291] Furthermore, the component (D1) 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.

[0292] The component (D1) may be used singly, or in combination of two or more types. When the resist composition contains the component (D1), the amount of the component (D1) within the resist composition is typically within a range from 0.01 to 5 parts by mass, relative to 100 parts by mass of the component (A). By ensuring that the amount is within this range, improvements can be achieved in terms of the resist pattern shape, stability over time during storage, and the like.

[0293] The component (B) and / or component (D) may be contained in the form of a compound, in the form of being incorporated into the component (A), or both. When the component (B) is contained in the component (A), it is preferable that a structure containing the compounds (B1) to (B3), and optionally (B4) and / or (B5), is contained as a repeating unit in the component (A).

[0294] <Component (E): At Least One Compound Selected from the Group Consisting of Organic Carboxylic Acids, Phosphorus Oxoacids, and Derivatives thereof> The resist composition of this embodiment may contain, as an optional component, at least one compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof, for the purposes of preventing sensitivity degradation and improving the resist pattern shape and post-exposure stability, etc. Suitable organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, hydroxybenzoic acid, salicylic acid, phthalic acid, terephthalic acid, and isophthalic acid.

[0295] Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Derivatives of phosphorus oxoacids include esters in which the hydrogen atoms of the oxoacids are substituted with hydrocarbon groups, and examples of the hydrocarbon groups include alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Derivatives of phosphoric acid include phosphate esters such as di-n-butyl phosphate and diphenyl phosphate.

[0296] Examples of the derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Examples of the derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid.

[0297] Among the above, the component (E) is preferably an organic carboxylic acid, and more preferably an aromatic carboxylic acid. Specifically, benzoic acid, hydroxybenzoic acid, salicylic acid, phthalic acid, terephthalic acid, and isophthalic acid are preferred, and salicylic acid is more preferred. In the resist composition of this embodiment, the component (E) may be used alone or in combination of two or more types.

[0298]

[0122] When the resist composition contains the component (E), the amount of the component (E) relative to 100 parts by mass of the component (A) is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass.

[0299] <Component (F): Fluorine Additive Component> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as “component (F)”) as a hydrophobic resin. The component (F) is used to impart water repellency to the resist film, and when used as a resin separate from the component (A), it improves lithography properties.

[0300] As the component (F), for example, fluorine-containing polymeric compounds described in JP-A Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569, and 2011-128226 can be used.

[0301] More specifically, the component (F) can be a polymer having a structural unit (f11) represented by the following general formula (f1-1). The polymer having the structural unit (f11) represented by the following general formula (f1-1) is preferably a polymer (homopolymer) consisting solely of the structural unit (f11) represented by the following formula (f1-1); a copolymer of the structural unit (f11) with the structural unit (a3); or a copolymer of the structural unit (f11), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a3). Here, the structural unit (a3) ​​copolymerized with the structural unit (f11) is preferably a structural unit containing an acid-dissociable group represented by the above formula (a3-r-2).

[0302]

[0303] [In the formula, R is the same as above. １０２ and Rf １０３ Rf each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; １０２ and Rf １０３ may be the same or different. １ is an integer of 0 to 5, and Rf １０１ is an organic group containing a fluorine atom.

[0304] In general formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. １０２ and Rf １０３ 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 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.

[0305] In general formula (f1-1), n ｆ１ is an integer of 0 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2. In general formula (f1-1), Rf １０１ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.

[0306] The fluorine atom-containing hydrocarbon group may be linear, branched, or cyclic, and preferably contains 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. In addition, the fluorine atom-containing hydrocarbon group preferably has 25% or more of the hydrogen atoms fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure.

[0307] Among them, 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 more preferred, and —CH ２ -CF ３ The component (F) preferably contains a structural unit having an acid-dissociable group, and more preferably contains a structural unit containing an acid-dissociable group represented by formula (a3-r-2).

[0308] 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 weight average molecular weight is equal to or less than the upper limit of this range, the resist composition of this embodiment will have sufficient solubility in a resist solvent for use as a resist, and when the weight average molecular weight is equal to or greater than the lower limit of this range, the resist composition of this embodiment will have good dry etching resistance and the cross-sectional shape of the resist pattern will be favorable.

[0309] The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.0 to 2.5. In the resist composition of this embodiment, the component (F) may be used either alone or in combination with two or more different 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).

[0310] <Organic Solvent Component (S)> The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as “component (S)”).

[0311] The component (S) may be any solvent capable of dissolving the various components used to form a homogeneous solution, and any solvent may be appropriately selected from among those known to date as solvents for chemically amplified resist compositions. In the resist composition of this embodiment, the component (S) may be used alone, or as a mixed solvent of two or more different solvents. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0312] Also preferred as component (S) is a mixed solvent of PGMEA and a polar solvent. The blending ratio (mass ratio) can be determined appropriately taking into consideration the compatibility between PGMEA and the polar solvent, etc. Also preferred as component (S) is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone. In this case, the blending ratio is preferably 70:30 to 95:5 by mass.

[0313] There are no particular limitations on the amount of component (S) used, and it is set appropriately depending on the coating film thickness and at a concentration that allows application to a substrate, etc. Component (S) is generally used so that the solids concentration of the resist composition falls within the range of 0.1 to 20 mass %, and preferably 0.2 to 15 mass %. The resist composition of this embodiment can further contain, as desired, miscible additives such as additional resins for improving the performance of the resist film, dissolution inhibitors, plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like.

[0314] The resist composition of this embodiment contains the above-mentioned component (A) and component (B), and, if necessary, the above-mentioned optional components. Suitable examples include resist compositions containing the component (A), component (B), and component (D). Furthermore, suitable examples include resist compositions containing the component (A), component (B), component (D), and component (F).

[0315] As described above, the resist composition of this embodiment contains an acid generator component (B) having a compound (B1) represented by formula (b1), a compound (B2) represented by formula (b2), and a compound (B3) represented by formula (b3). Because the acid generator component (B) contains three salts of the compound (B1) represented by formula (b1), the compound (B2) represented by formula (b2), and the compound (B3) represented by formula (b3), sensitivity and roughness performance are improved. Because the compound (B1) represented by formula (b1) is a salt containing a methide of a specific structure, it has high acid strength and is effective in increasing sensitivity as a photoacid generator (PAG) with high deprotection performance. Furthermore, because the compound (B2) represented by formula (b2) is a salt containing a sulfonic acid of a specific structure, acid strength can be adjusted, and it is effective in increasing sensitivity and improving roughness performance by achieving both deprotection performance in exposed areas and acid diffusion suppression performance in unexposed areas. Furthermore, since the compound (B3) represented by formula (b3) is a salt having a carboxylic acid, it is effective in improving roughness performance as a photodecomposable base (PDB) that suppresses acid diffusion, and therefore it is presumed that the resist composition of this embodiment will improve sensitivity and roughness performance.

[0316] (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, and developing the exposed resist film to form a resist pattern. One embodiment of this method of forming a resist pattern can be carried out as follows, for example. 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)) at a temperature of 80 to 150°C for 40 to 120 seconds, preferably 50 to 90 seconds, to form a resist film.

[0317] Next, the resist film is subjected to selective exposure using an exposure device such as an electron beam lithography device or an EUV exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without a mask pattern. Thereafter, a bake (post-exposure bake (PEB)) treatment is performed, for example, at a temperature of 80 to 150°C for 40 to 120 seconds, preferably 50 to 90 seconds. Next, the resist film is developed. The development treatment is performed using an alkaline developer in the case of an alkaline development process, or a developer containing an organic solvent (organic developer) in the case of a solvent development process. After the development treatment, a rinse treatment is preferably performed. For the rinse treatment, a water rinse using pure water is preferred in the case of an alkaline development process, and a rinse containing an organic solvent is preferred in the case of a solvent development process.

[0318] In the case of a solvent development process, after the development treatment or rinsing treatment, a treatment may be performed to remove the developer or rinsing solution adhering to the pattern using a supercritical fluid. After the development treatment or rinsing treatment, drying is performed. In addition, in some cases, a baking treatment (post-baking) may be performed after the development treatment. In this manner, a resist pattern can be formed.

[0319] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those having a predetermined wiring pattern formed thereon. More specifically, examples include silicon wafers, metal substrates such as copper, chromium, iron, and aluminum, and glass substrates. Materials for the wiring pattern include copper, aluminum, nickel, and gold. The wavelength used for exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, and soft X-rays can be used. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB, or EUV.

[0320] The exposure method for the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or liquid immersion lithography, but is preferably liquid immersion lithography. Liquid immersion lithography 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 that state.

[0321] The immersion medium is preferably a solvent having a refractive index greater than that of air and less than that of the resist film to be exposed. The refractive index of such a solvent is not particularly limited as long as it is within the above-mentioned range. Examples of solvents having a refractive index greater than that of air and less than that of the resist film include water, fluorine-based inert liquids, silicon-based solvents, and hydrocarbon-based solvents. Water is preferably used as the immersion medium. Examples of alkaline developers used in the development treatment in the alkaline development process include 0.1 to 10 mass % aqueous tetramethylammonium hydroxide (TMAH) solutions.

[0322] 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.

[0323] 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. Examples of nitrile-based solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0324] 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.

[0325] 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 discharging the developer while scanning a developer discharging nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0326] The rinse treatment (cleaning treatment) using a rinse liquid can be carried out by a known rinse method, such as a method of continuously discharging the rinse liquid onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse liquid for a certain period of time (dipping method), or a method of spraying the rinse liquid onto the surface of the support (spray method).

[0327] 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).

[0328] The resist pattern forming method of the present embodiment, as explained above, uses the resist composition according to the above-mentioned embodiment of the present invention, and therefore when forming a resist pattern, high sensitivity can be achieved, and a resist pattern with excellent lithography properties and a good shape can be formed.

[0329] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0330] Using the compounds shown below, polymer compounds (A-1) to (A-10) were synthesized with the composition ratios shown in Table 1. In the polymer compounds (A-1) to (A-10) synthesized from the compounds shown below, when there are two structural units, the structural units are represented as l and m from the left, and when there are three structural units, the structural units are represented as l, m, and n from the left. Regarding the obtained polymer compounds, １３ The copolymerization 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) and molecular weight dispersity (Mw / Mn) calculated in terms of standard polystyrene determined by GPC measurement are also shown in Table 1.

[0331]

[0332]

[0333]

[0334] <Preparation of Resist Compositions> (Examples 1 to 23, Comparative Examples 1 to 5) The components shown in Table 2 were mixed and dissolved in solvent S-1 to prepare the resist compositions of each example.

[0335]

[0336] In Table 2, the abbreviations have the following meanings: In Table 2, the numerical values ​​corresponding to the abbreviations indicate the content (parts by mass) of each substance.

[0337] A-1 to A-10: The above-mentioned polymeric compounds A-1 to A-10. B1-1 to B1-6: Acid generator compounds (B1) consisting of compounds represented by the following chemical formulas B1-1 to B1-6. B2-1 to B2-6: Acid generator compounds (B2) consisting of compounds represented by the following chemical formulas B2-1 to B2-6. B3-1 to B3-6: Acid generator compounds (B3) consisting of compounds represented by the following chemical formulas B3-1 to B3-6. D-1: Nitrogen-containing organic compound (D1) consisting of a compound represented by the following chemical formula D-1. S-1: A mixed solvent obtained by mixing the above-mentioned propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether in a mass ratio of 70:30. F1-1: Hydrophobic resin consisting of a compound represented by the following chemical formula F1-1 (composition ratio: from the left, each structural unit is represented as l and m, l / m=80 / 20, Mw: 26000, Mw / Mn: 1.5).

[0338]

[0339]

[0340]

[0341]

[0342]

[0343] <Formation of Resist Pattern> An organic antireflective coating composition "ARC95" (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 98 nm. A resist composition was applied to the antireflective coating using a spinner, and then prebaked (PAB) on a hot plate at 100°C for 60 seconds and dried, thereby forming a resist film with a thickness of 90 nm.

[0344] Using an ArF immersion exposure system NSR-S610C [Nikon Corporation; NA (numerical aperture) = 1.30, dipole (in / out) = 0.78 / 0.98) with Polano, immersion medium: water], the resist film was selectively irradiated with an ArF excimer laser (193 nm) through a photomask (6% halftone). Subsequently, a PEB treatment was performed at 90°C for 60 seconds. Next, alkaline development was performed for 10 seconds using a 2.38% by weight aqueous TMAH solution (trade name: NMD-3, Tokyo Ohka Kogyo Co., Ltd.) at 23°C, followed by a 30-second rinse with purified water and subsequent drying. As a result, a 1:1 line-and-space pattern (hereinafter referred to as an LS pattern) with a line width of 45 nm and a pitch of 90 nm was formed.

[0345] [Evaluation of Optimal Exposure Dose (Eop)] The optimal exposure dose Eop (mJ / cm) for forming a 1:1 LS pattern with a line width of 45 nm and a pitch of 90 nm in the above <Formation of Resist Pattern> was ２ The results are shown in Table 3 below.

[0346] [Evaluation of LWR (Line Width Roughness)] For the LS patterns formed in the <Formation of Resist Pattern> above, 3σ, a measure of LWR, was determined. The results are shown in Table 3 below. "3σ" represents three times the standard deviation (σ) (unit: nm) obtained from the measurement results of 400 line positions measured in the longitudinal direction of the lines using a scanning electron microscope (accelerating voltage 500 V, product name: CG5000, manufactured by Hitachi High-Technologies Corporation). A smaller 3σ value means that the roughness of the line sidewalls is smaller, and an LS pattern with a more uniform width is obtained.

[0347]

[0348] The results shown in Table 3 confirm that the resist compositions of the examples according to the present invention enable high sensitivity in resist pattern formation, and also enable the formation of resist patterns with excellent lithography properties and good shapes.

[0349] The present invention is able 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.

[0350] 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 thereto without departing from the spirit and scope of the present invention. This application is based on Korean patent application (10-2023-0121560) filed on September 13, 2023, 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; and an acid generator component (B) that generates an acid upon exposure, wherein the acid generator component (B) has a compound (B1) represented by the following formula (b1), a compound (B2) represented by the following formula (b2), and a compound (B3) represented by the following formula (b3): [In the formula, R １ each independently represents a fluorinated alkyl group or a fluorinated cycloalkyl group, or at least two R １ can be combined to form a fluorinated alkylene group. １ may be the same or different. ２ and R ３ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. ２ In the formula, the group adjacent to the S atom is -CH ２ m is an integer of 1 or more, M ｍ＋ is an onium cation having a valence of m.

2. The resist composition according to claim 1, wherein the compound (B1) represented by formula (b1) is a compound represented by the following formula (b1-1): [In the formula, R １’ Each independently represents -(CF ２ ) ｎ -, and n is an integer from 1 to 4. １’’ Each of R is independently a fluorinated alkyl group which may have a fluorine atom or a hydrogen atom. １’ , R １’’ may be the same or different; m is an integer of 1 or more; M ｍ＋ is an onium cation having a valence of m.

3. R ​​in formula (b2) ２ adjacent to the S atom ２ 3. The resist composition according to claim 1, wherein the alkyl group is a chain alkyl group having 1 to 4 carbon atoms containing a - group and optionally having a substituent, and the optionally having a substituent is an oxo group, an alkyl group, a cyclic group, an ether bond, an ester bond, or a combination thereof.

4. The base component (A) contains a lactone-containing cyclic group, —SO ２ 3. The resist composition according to claim 1, which has a structural unit containing either a -containing cyclic group or a carbonate-containing cyclic group.

5. The resist composition according to claim 1 or 2, further comprising a fluorine-based additive (F).

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

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