Resist composition and method for forming resist pattern

Abstract

To provide a resist composition capable of achieving high sensitivity and forming a resist pattern excellent in lithography characteristics, and a method for forming a resist pattern.SOLUTION: The resist composition which generates an acid upon exposure to light and whose solubility in a developing solution is changed by the action of the acid contains a base component (A) whose solubility in the developing solution is changed by the action of the acid, an acid generator component (B) which generates an acid upon exposure to light, and a fluorine-containing additive component (F). The base material (A) contains a polymer compound (a1) having a structural unit (a1) represented by General Formula (a2 - 1) described in the specification and a structural unit (SO2) containing any one of a lactone-containing cyclic group, a - a2 - containing cyclic group, or a carbonate-containing cyclic group represented by General Formula (a1 - 1) described in the specification.SELECTED DRAWING: None

Description

[Technical Field]

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

[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 of the resist film so that it does not dissolve in a developer is called a negative-type resist. In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, advances in lithography technology have led to rapid progress in miniaturization of patterns. A common method of miniaturization is to shorten the wavelength (increase the energy) of the exposure light source. Specifically, ultraviolet rays such as g-line and i-line have traditionally been used, but currently, mass production of semiconductor elements is being carried out using KrF excimer lasers and ArF excimer lasers. Furthermore, research is also being conducted on EUV (extreme ultraviolet), EB (electron beam), X-rays, and other light sources with shorter wavelengths (higher energy) than these excimer lasers.

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

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

[0005] The base resin used in a chemically amplified resist composition generally contains a plurality of structural units in order to improve lithography properties and the like. For example, Patent Document 1 discusses a resist composition and a method of forming a resist pattern that can achieve high sensitivity, have excellent lithography properties, and form a resist pattern with a good shape. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-168504 Summary of the Invention [Problem to be solved by the invention]

[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. However, conventional resist compositions such as those described in Patent Document 1 above still have 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. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention employs the following configuration. That is, a first aspect of the present invention is a resist composition that generates an acid upon exposure, and whose solubility in a developer changes due to the action of the acid, The photosensitive resin composition contains a base component (A) whose solubility in a developer changes under the action of an acid, an acid generator component (B) that generates an acid upon exposure, and a fluorine additive component (F), The base component (A) comprises a polymeric compound (A1) having a structural unit (a1) represented by the following general formula (a1-1) and a structural unit (a2) containing a lactone-containing cyclic group, an —SO—-containing cyclic group, or a carbonate-containing cyclic group represented by the following general formula (a2-1): It is a resist composition.

[0010] [ka]

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

[0012] [ka]

[0013] In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 21 represents a single bond or a divalent linking group. 21 is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, where R' represents a hydrogen atom or a methyl group. 21 If -O-, Ya 21 does not become -CO-. Ra 21 represents a lactone-containing cyclic group, a carbonate-containing cyclic group, or an —SO—-containing cyclic group.

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

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

[0016] In the present disclosure, the term "aliphatic" is a relative concept to aromatic, and is defined as meaning a group, compound, etc. that does not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. A "halogenated alkyl group" is an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine, and iodine atoms. The term "fluorinated alkyl group" or "fluorinated alkylene group" refers to an alkyl group or alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrase "optionally substituted" includes both cases where a hydrogen atom (-H) is replaced with a monovalent group and cases where a methylene group (-CH2-) is replaced with a divalent group. The term "exposure" is a general concept that includes irradiation with radiation.

[0017] The "base component" refers to an organic compound having film-forming ability, and preferably an organic compound having a molecular weight of 500 or more is used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and, in addition, nano-level resist patterns are easily formed. Organic compounds used as base components are broadly classified into non-polymers and polymers. As non-polymers, compounds having a molecular weight of 500 or more and less than 4000 are typically used. Hereinafter, the term "low molecular weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000. As polymers, compounds having a molecular weight of 1000 or more are typically used. Hereinafter, the terms "resin," "polymer compound," or "polymer" refer to a polymer having a molecular weight of 1000 or more. The molecular weight of a polymer is determined by the weight average molecular weight calculated in terms of polystyrene by GPC (gel permeation chromatography).

[0018] The term "structural unit derived from an acrylate ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylate ester. An "acrylic acid ester" is a compound in which the hydrogen atom at the terminal carboxyl group of acrylic acid (CH2=CH-COOH) is substituted with an organic group. 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. In addition, the acrylic acid ester has a substituent (R α0 ) is substituted with a substituent containing an ester bond, or α0 This also includes α-hydroxyacrylic esters in which the α-position carbon atom of an acrylic ester is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-position carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of the acrylic ester is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom has been substituted with a substituent may be referred to as an α-substituted acrylic ester. Furthermore, acrylic esters and α-substituted acrylic esters may be collectively referred to as "(α-substituted) acrylic esters."

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

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

[0021] In this disclosure, some structures represented by chemical formulas may have asymmetric carbon atoms, and may exist as enantiomers or diastereomers. In such cases, a single chemical formula represents all isomers. These isomers may be used alone or as a mixture. In the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

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

[0023] A resist composition according to a first aspect of the present invention is a resist composition that generates an acid upon exposure, and whose solubility in a developer changes due to the action of the acid, The composition contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes under the action of acid, an acid generator component (B) (hereinafter also referred to as "component (B)") that generates acid upon exposure to light, and a fluorine additive component (F) (hereinafter also referred to as "component (F)"); The base component (A) contains a polymeric compound (A1) (hereinafter also referred to as "component (A1)") having a structural unit (a1) represented by the following general formula (a1-1) and a structural unit (a2) containing a lactone-containing cyclic group, an -SO-containing cyclic group, or a carbonate-containing cyclic group represented by the following general formula (a2-1): When such a resist composition is used to form a resist film, it is possible to achieve high sensitivity and form a resist pattern with excellent lithography properties.

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

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

[0026] In an embodiment of the present invention, the structural unit (a1) represented by general formula (a1-1) has a structure having a carbon atom between the ester group and the cyclic hydrocarbon group, which allows for high sensitivity. Furthermore, since the structural unit (a1) represented by general formula (a1-1) has a structure having a carbon atom between the ester group and the cyclic hydrocarbon group, it is presumed that dissociation by acid is facilitated, thereby increasing the contrast between exposed and unexposed areas, and thereby enabling the formation of a resist pattern with a good shape.

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

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

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

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

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

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

[0033] <Constituent unit (a1)>

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

[0035] The term "acid-decomposable group" refers to a group having acid decomposability in which at least some of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases under the action of an acid include groups that decompose under the action of an acid to generate a polar group. Examples of polar groups include a carboxy group, a hydroxy group, an amino group, a sulfo group (-SO3H), etc. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as an "OH-containing polar group") is preferred, a carboxy group or a hydroxy group is more preferred, and a carboxy group is particularly preferred. More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0036] 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. 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. Therefore, 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, increasing the polarity. As a result, the polarity of the entire component (A1) increases. The increase in polarity relatively changes the solubility in the developer, increasing the solubility when the developer is an alkaline developer and decreasing the solubility when the developer is an organic developer.

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

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

[0039] [ka]

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

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

[0042] In general formula (a1-1), Ra 11 represents a cyclic hydrocarbon group having 5 to 8 carbon atoms. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be monocyclic or polycyclic, and is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 5 to 8 carbon atoms, more preferably 5 or 6 carbon atoms. Specific examples include cyclopentane and cyclohexane. The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 8 carbon atoms, more preferably 5 to 6 carbon atoms. Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene.

[0043] Specific examples of the aromatic hydrocarbon group include a group (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle, and a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings. The alkylene group bonded to the aromatic hydrocarbon ring preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.

[0044] Ra 11 The cyclic hydrocarbon group having 5 to 8 carbon atoms represented by is preferably an alicyclic hydrocarbon group which may have a substituent, and more preferably a monocyclic alicyclic hydrocarbon group which may have a substituent. Examples of this substituent include -R P1 , -R P2 -OR P1 , -R P2 -CO-R P1 , -R P2 -CO-OR P1 , -R P2 -O-CO-R P1 , -R P2 -OH, -RP2 -CN or -R P2 -COOH (hereinafter these substituents are collectively referred to as "Ra 05 ") are also examples. where R P1 is a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. Also, R P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. P1 and R P2 Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the alicyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic hydrocarbon group may have one or more of the above-mentioned substituents, or may have one or more of each of the above-mentioned substituents.

[0045] Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene.

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

[0047] [ka]

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

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

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

[0051] [ka]

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

[0053] <Constituent unit (a2)> The component (A1) contains, in addition to the structural unit (a1), a structural unit (a2) containing either a lactone-containing cyclic group, an —SO—-containing cyclic group, or a carbonate-containing cyclic group represented by the following general formula (a2-1):

[0054] [ka]

[0055] In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 21 represents a single bond or a divalent linking group. 21 is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, where R' represents a hydrogen atom or a methyl group. 21 If -O-, Ya 21 does not become -CO-. Ra 21 represents a lactone-containing cyclic group, a carbonate-containing cyclic group, or an —SO—-containing cyclic group.

[0056] In the structural unit (a2), Ra 21 When the component (A1) is used to form a resist film, the lactone-containing cyclic group, -SO2- containing cyclic group, or carbonate-containing cyclic group represented by the formula (A1) is effective in improving the adhesion of the resist film to the substrate. Furthermore, the presence of the structural unit (a2) improves lithography properties such as resolution, for example, by appropriately adjusting the acid diffusion length, improving the adhesion of the resist film to the substrate, and appropriately adjusting the solubility during development.

[0057] A "lactone-containing cyclic group" refers to a cyclic group containing a ring (lactone ring) containing -OC(=O)- in its ring skeleton. The lactone ring is counted as the first ring, and a group consisting of only a lactone ring is called a monocyclic group. If a group further contains other ring structures, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

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

[0059] [ka]

[0060] [In formulas (a2-r-1) to (a2-r-7), Ra' 21 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (-O-) or a sulfur atom (-S-), an oxygen atom, or a sulfur atom; n' is an integer of 0 to 2, and m' is 0 or 1. * is a bond.

[0061] In the general formulas (a2-r-1) to (a2-r-7), Ra' 21 The alkyl group in the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' 21 The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the alkoxy group in the formula (1) is preferably linear or branched. 21 Examples of the alkyl group include a group in which the alkyl groups mentioned above are linked to an oxygen atom (—O—). Ra' 21 Examples of the halogen atom in include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Ra' 21 The halogenated alkyl group in the formula Ra' is 21Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0062] Ra' 21 In -COOR" and -OC(=O)R", R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group. The alkyl group in R'' may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples of the lactone-containing cyclic group in R″ include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7) above. The carbonate-containing cyclic group in R″ is the same as the carbonate-containing cyclic group described below, and specific examples include groups represented by the general formulae (ax3-r-1) to (ax3-r-3). The -SO2-containing cyclic group in R'' is the same as the -SO2-containing cyclic group described below, and specific examples include groups represented by general formulae (a5-r-1) to (a5-r-4). Ra' 21 The hydroxyalkyl group in the formula (I) preferably has 1 to 6 carbon atoms, and specifically, the hydroxyalkyl group in the formula (I) is preferably a hydroxyalkyl group having 1 to 6 carbon atoms. 21 and a group in which at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0063] In the general formulae (a2-r-2), (a2-r-3), and (a2-r-5), the alkylene group having 1 to 5 carbon atoms for A" is preferably a straight-chain or branched-chain alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include groups in which -O- or -S- is present at the terminal or between carbon atoms of the alkylene group, such as -O-CH2-, -CH2-O-CH2-, -S-CH2-, and -CH2-S-CH2-. A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

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

[0065] [ka]

[0066] [ka]

[0067] The term "-SO2-containing cyclic group" refers to a cyclic group containing a ring containing -SO2- in its ring skeleton, specifically a cyclic group in which the sulfur atom (S) in -SO2- forms part of the ring skeleton of the cyclic group. The ring containing -SO2- in the ring skeleton is counted as the first ring, and if it contains only that ring, it is called a monocyclic group. If it contains other ring structures, it is called a polycyclic group regardless of the structure. The -SO2- containing cyclic group may be a monocyclic group or a polycyclic group. The -SO2- containing cyclic group is preferably a cyclic group containing -O-SO2- in its ring skeleton, i.e., a cyclic group containing a sultone ring in which -OS- in -O-SO2- forms part of the ring skeleton. More specific examples of the —SO2—-containing cyclic group include groups represented by the following general formulae (a5-r-1) to (a5-r-4).

[0068] [ka]

[0069] [In the formula, Ra' 51 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; and n' is an integer of 0 to 2. * is a bond.

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

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] The term "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -OC(=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. 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. The carbonate-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following general formulae (ax3-r-1) to (ax3-r-3).

[0075] [ka]

[0076] [In the formula, Ra' x31are 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 an -SO2- containing cyclic group; 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; p' is an integer of 0 to 3, and q' is 0 or 1. * is a bond.

[0077] In the general formulae (ax3-r-2) to (ax3-r-3), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3) and (a2-r-5). Ra' x31 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each represented by Ra' 21 Examples of the above include those mentioned in the explanation of the above. Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are listed below.

[0078] [ka]

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

[0080] In the formula (a2-1), Ya 21 The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

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

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

[0083] Linear or branched aliphatic hydrocarbon groups The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0084] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0085] Aliphatic hydrocarbon groups containing rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0086] The cyclic aliphatic hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and still more preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0087] Divalent linking groups containing heteroatoms: Ya 21is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -, wherein Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, an acyl group, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. General formula-Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -Medium, Y 21 and Y 22are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the above-mentioned Ya 21 Examples of the divalent linking group include the same groups as those (divalent hydrocarbon groups which may have a substituent) mentioned in the description of the divalent linking group in the above. Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred. Y 22 is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, in the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22 The group represented by - is a group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) b’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

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

[0089] In the above formula (a2-1), Ra 21 is a lactone-containing cyclic group, an —SO 2 —-containing cyclic group, or a carbonate-containing cyclic group. Ra 21 Suitable examples of the lactone-containing cyclic group, the -SO2- containing cyclic group, and the carbonate-containing cyclic group in the formula (a2-r-1), (a2-r-7), (a5-r-1), (a5-r-4), and (ax3-r-1), respectively, are the groups represented by the general formulas (ax3-r-3). Ra 21 Among the above, is preferably a lactone-containing cyclic group or an -SO2- containing cyclic group, more preferably a lactone-containing cyclic group, further preferably a group represented by any one of the general formulae (a2-r-1) to (a2-r-7), and particularly preferably a group represented by the general formula (a2-r-1) or (a2-r-2). Specifically, any one of the groups represented by the formulae (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) is preferred, and any one of the groups represented by the formulae (r-lc-1-1) to (r-lc-1-7), and (r-lc-2-1) to (r-lc-2-13) is more preferred.

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

[0091] [ka]

[0092] The structural unit (a2) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) relative to the total (100 mol%) of all structural units constituting the component (A1) is preferably 10 to 65 mol%, more preferably 20 to 65 mol%, even more preferably 30 to 60 mol%, and particularly preferably 40 to 60 mol%. When the proportion of the structural unit (a2) is at least 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. When the proportion of the structural unit (a2) is at most the upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

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

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

[0095] Regarding the structural unit (a3): In addition to the structural units (a1) and (a2), the component (A1) may further include a structural unit (a3) ​​containing a polar group-containing aliphatic hydrocarbon group (provided that this does not fall under the category of structural unit (a1) or structural unit (a2)). In other words, the resin component (A1) preferably further includes a structural unit (a3) ​​containing a polar group-containing aliphatic hydrocarbon group. By including the structural unit (a3) ​​in the component (A1), the hydrophilicity of the component (A) is enhanced, which contributes to improved resolution and also makes it possible to appropriately adjust the acid diffusion length.

[0096] Examples of the polar group include a hydroxyl group, a cyano group, a carboxyl group, and a hydroxyalkyl group in which some of the hydrogen atoms of an alkyl group have been substituted with fluorine atoms, with a hydroxyl group 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 a monocyclic group or a polycyclic group, and can be appropriately selected from the many groups proposed for use in resins for resist compositions for ArF excimer lasers.

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

[0098] When the cyclic group is a polycyclic group, the polycyclic group 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 in which two or more hydrogen atoms have been removed from bicycloalkanes, tricycloalkanes, tetracycloalkanes, etc. Specific examples include groups in which two or more hydrogen atoms have been removed from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane are industrially preferred.

[0099] There are no particular limitations on the structural unit (a3), and any structural unit can be used as long as it contains a polar group-containing aliphatic hydrocarbon group. As the structural unit (a3), 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 is preferred. 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 (a3) ​​is preferably a structural unit derived from a hydroxyethyl ester of acrylic acid. Furthermore, when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a polycyclic group, preferred examples of the structural unit (a3) ​​include structural units represented by the following formulas (a3-1), (a3-2), and (a3-3); and when the hydrocarbon group is a monocyclic group, preferred examples of the structural unit (a3) ​​include structural units represented by formula (a3-4).

[0100] [ka]

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

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

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

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

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

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

[0107] The component (A1) contained in the resist composition may use either a single type of compound, or a combination of two or more types of compounds. In the resist composition according to an embodiment of the present invention, the component (A1) can be a polymeric compound that has a repeating structure of the structural unit (a1) and the structural unit (a2), and a polymeric compound that has a repeating structure of two or more types of the structural unit (a1) and the structural unit (a2) is preferred. In addition to the combination of the two constituent units described above, the constituent units described above may be combined as a third or more constituent units as appropriate to achieve the desired effect.

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

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

[0110] The component (A1) can be produced by dissolving the monomers that derive the respective structural units in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing the resulting mixture. Alternatively, the component (A1) can be produced by dissolving a monomer that derives the structural unit (a1) and the structural unit (a2), and, if necessary, a monomer that derives a structural unit other than the structural units (a1) and (a2), in a polymerization solvent, adding a radical polymerization initiator such as those described above to the solution to polymerize, and then carrying out a deprotection reaction. During polymerization, a chain transfer agent such as HS-CH2-CH2-CH2-C(CF3)2-OH may be used in combination to introduce a -C(CF3)2-OH group to the terminal. Copolymers incorporating hydroxyalkyl groups in which some of the alkyl group's hydrogen atoms have been substituted with fluorine atoms are effective in reducing development defects and LER (line edge roughness: unevenness on the line sidewalls).

[0111] The weight average molecular weight (Mw) of the component (A1) (based on polystyrene standards measured by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000. When the Mw of the component (A1) is less than or equal to the preferred upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is at least the preferred lower limit of this range, the compound exhibits good dry etching resistance and the cross-sectional shape of the resist pattern. The dispersity (Mw / Mn) of the 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.

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

[0113] The proportion of the component (A1) within the component (A), relative to the total mass of the component (A), is preferably 25 mass% or more, more preferably 50 mass% or more, 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 is more easily formed.

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

[0115] <Acid generator component (B)> The resist composition according to an embodiment of the present invention contains, in addition to the component (A), an acid generator component (B) (hereafter referred to as "component (B)") that generates acid upon exposure. There are no particular restrictions on the component (B), and any of the acid generators that have been proposed as acid generators for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl or bisaryl sulfonyl diazomethanes and poly(bissulfonyl) diazomethanes, nitrobenzyl sulfonate-based acid generators, imino sulfonate-based acid generators, and disulfone-based acid generators. The component (B) preferably contains an ionic compound, and more preferably contains a compound (B1) consisting of an onium salt (hereinafter referred to as "component (B1)").

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

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

[0118] [ka]

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

[0120] [Anion part (R b1 -Y b1 -V b1 -CFR f1 -SO3 - )] In the general formula (b-1), R b1 represents a monovalent hydrocarbon group having 17 to 50 carbon atoms and a polycyclic hydrocarbon steroid skeleton which may have a substituent. R b1Examples of the polycyclic hydrocarbon group represented by include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, tetracycloalkane, or the like having 7 to 30 carbon atoms. Specific examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane.

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

[0122] These polycyclic hydrocarbon groups may have a substituent. Examples of the substituent in the polycyclic hydrocarbon group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. A hydroxyl group or an alkyl group having 1 to 5 carbon atoms is preferred, and a hydroxyl group is more preferred.

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

[0124] [ka]

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

[0126] Rb1 The steroid skeleton of the formula (St) may contain a substituent. For example, the ring structure represented by the formula (St) may have, as a substituent, an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group), a carboxy group, an oxo group (=O), an alkoxy group, an alkylcarbonyloxy group (preferably an acetoxy group), a formyloxy group (HC(=O)-O-), a hydroxyl group, a lactone-containing cyclic group, or the like. The lactone-containing cyclic group may have one or more double bonds in the ring structure. The number of double bonds is not particularly limited, but is preferably one.

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

[0128] In the formula (b-1), Y b1 represents a single bond or a divalent linking group containing a hetero atom. The heteroatom in the divalent linking group containing a heteroatom preferably contains an oxygen atom, but may contain a heteroatom other than an oxygen atom. Examples of the heteroatom other than an oxygen atom include a nitrogen atom and a sulfur atom. Y b1 Examples of the divalent linking group containing a hetero atom in the formula (I) include non-hydrocarbon heteroatom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-OC(=O)-), an amide bond (-C(=O)-NH-, -NH-C(=O)-), a carbonyl group (-C(=O)-), and a carbonate bond (-OC(=O)-O-); and combinations of such non-hydrocarbon heteroatom-containing linking groups with alkylene groups. A sulfonyl group (-SO2-) may be further linked to such combinations. Preferably, Yb1 The divalent linking group containing a hetero atom in the formula (I) is a divalent linking group containing at least one functional group selected from the group consisting of a carboxylic acid ester group, an ether group, a carbonate ester group, a carbonyl group, and an amide group. Examples of such combinations include linking groups represented by the following formulae (y-al-1) to (y-al-8).

[0129] [ka]

[0130] [In the formula, V' 101 is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' 102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0131] V' 102 The divalent saturated hydrocarbon group in V' is preferably an alkylene group having 1 to 30 carbon atoms. 102 The alkylene group in is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 5 carbon atoms.

[0132] V' 101 and V' 102 The alkylene group in may be a straight-chain alkylene group or a branched-chain alkylene group. V' 101 and V' 102Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. 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.

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

[0134] In the above formula (b1), V b1 represents an alkylene group having two or more carbon atoms, a fluorinated alkylene group, or an ester group. V b1 The alkylene group or fluorinated alkylene group in may be linear or branched, but is preferably linear. V b1 The alkylene group having 2 or more carbon atoms in the formula (I) preferably has 2 to 4 carbon atoms, and more preferably has 2 to 3 carbon atoms. Vb1 The fluorinated alkylene group in the formula (V) includes a group in which some or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms. b1 The fluorinated alkylene group in R f1 It is preferable that the carbon atom adjacent to the carbon atom to which is bonded has at least one fluorine atom or a fluorinated alkylene group having 1 to 3 carbon atoms. V b1 Particularly preferred examples of include an ester group and a fluorinated alkylene group having 1 to 3 carbon atoms. The ester group and the fluorinated alkylene group having 1 to 3 carbon atoms are preferably Y b1 -V b1 But, Y b1 -(-O-(C=O)-, Y b1 -(CH2) n -CHF- or Y b1 -(CH2) n It is preferably represented by -CF2- (n is an integer of 0 to 2).

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

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

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

[0142] [ka]

[0143] [In general formula (b-2), R1 to R3 each independently represent an at least partially fluorinated alkyl group or cycloalkyl group, or at least two of R1 to R3 may be bonded to form a fluorinated alkylene group. m is an integer of 1 or more, and M m+ is an m-valent organic cation.

[0144] [Anion part] In general formula (b-2), R1 to R3 each independently represent an at least partially fluorinated alkyl group (preferably having 1 to 8 carbon atoms) or cycloalkyl group (preferably having 3 to 8 carbon atoms), or at least two of R1 to R3 combine to represent a fluorinated alkylene group. It is preferable that R1 to R3 each independently represent a fluorinated alkyl group (preferably having 1 to 8 carbon atoms) or a fluorinated cycloalkyl group (preferably having 3 to 8 carbon atoms).

[0145] Examples of the fluorinated alkyl group represented by R1 to R3 include perfluoro or partially fluorinated alkyl groups, such as a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-butyl group, a heptafluoro-n-propyl group, a heptafluoro-i-propyl group, a nonafluoro-n-butyl group, a nonafluoro-2-methylpropyl group, a nonafluoro-1-methylpropyl group, a nonafluoro-t-butyl group, a perfluoro-n-pentyl group, a perfluoroneopentyl group, a perfluoro-n-hexyl group, a perfluoro-n-heptyl group, and a perfluoro-n-octyl group.

[0146] The fluorinated cycloalkyl group represented by R1 to R3 includes a group in which at least one hydrogen atom of a cycloalkyl group is substituted with a fluorine atom (fluorocycloalkyl group), such as a 3- to 20-membered fluorocycloalkyl group such as a monofluorocyclopentyl group, a difluorocyclopentyl group, a nonafluorocyclopentyl group, a monofluorocyclohexyl group, a difluorocyclohexyl group, or an undecafluorocyclohexyl group. The fluorocycloalkyl group is preferably a 5- to 20-membered ring, and more preferably a 5- to 15-membered ring.

[0147] Examples of fluorinated alkylene groups in which at least two of R1 to R3 are bonded include perfluoro or partially fluorinated alkylene groups, such as difluoromethylene, tetrafluoroethylene, hexafluoro-n-propylene, hexafluoro-i-propylene, octafluoro-n-butylene, octafluoro-2-methylpropylene, octafluoro-1-methylpropylene, octafluoro-t-butylene, perfluoro-n-pentylene, perfluoroneopentylene, perfluoro-n-hexylene, perfluoro-n-heptylene, and perfluoro-n-octylene.

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

[0149] [ka]

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

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

[0152] [ka]

[0153] [In the formula, R 201 ~R 207 R each independently represents an aryl group, an alkyl group, or an alkenyl group which may have a substituent. 201 ~R 203 , R 206 ~R 207 may be bonded to each other to form a ring together with the sulfur atom in the formula. 208 ~R 209 R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-.]

[0154] In the above general formulas (ca-1) to (ca-3), R 201 ~R 207The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7).

[0155] [ka]

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

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

[0158] R' 201The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. R' 201 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201 Specific examples of the aromatic hydrocarbon group in include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0159] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 30 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which 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, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0160] Among them, R' 201 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0161] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0162] Also, R' 201 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include the lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above, the —SO—-containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above, and other heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16).

[0163] [ka]

[0164] R' 201 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[0165] An optionally substituted chain alkyl group: R' 201 The chain alkyl group may be either a straight chain or a branched chain. 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 decanyl 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. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0166] An optionally substituted chain alkenyl group: R' 201 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0167] R' 201 Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, the above-mentioned R' 201 Examples of the cyclic groups include the cyclic groups shown in the formula:

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

[0169] Among them, R' 201 is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7), or an —SO2- containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4) is preferred.

[0170] In the above general formulas (ca-1) to (ca-3), R 201 ~R 203 , R 206 ~R 207 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may not contain a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO2-, -SO3-, -COO-, -CONH-, or -N(R N )-(applicable R N is an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0171] R 208 ~R 209 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0172] R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 210 As the -SO2- containing cyclic group which may have a substituent in the formula (a5-r-1), an "-SO2- containing polycyclic group" is preferred, and a group represented by the above general formula (a5-r-1) is more preferred.

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

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [In the formula, g1, g2, and g3 represent the number of repeating units, where g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20.]

[0178] [ka]

[0179] [ka]

[0180] [ka]

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

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

[0183] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0184] [ka]

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

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

[0187] In the resist composition according to an embodiment of the present invention, the component (B) may be used either as a single type, or in combination of two or more types. In the resist composition according to an embodiment of the present invention, the amount of the component (B) relative to 100 parts by mass of the component (A) is preferably 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass. By ensuring that the amount of component (B) falls within the above-mentioned preferred range, sufficient pattern formation is achieved. Furthermore, when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is also favorable.

[0188] <Fluorine additive component (F)> The resist composition according to an embodiment of the present invention contains a fluorine additive component (hereafter referred to as "component (F)"). Component (F), which is used to impart water repellency to the resist film, is a hydrophobic resin separate from component (A) and tends to be unevenly distributed on the surface of the resist film. For this reason, its use in a resist composition reduces the fluorine additive component in the resist film, which in turn increases the density of component (A) and the acid generator component, thereby enhancing the contrast between exposed and unexposed areas and improving the lithography properties of the resist film. As the component (F), for example, the fluorine-containing polymer compounds described in JP-A Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569, and 2011-128226 can be used. More specifically, the component (F) may be a polymer having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting solely of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate.

[0189] [ka]

[0190] [In general formula (f1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Rf 102 and Rf 103 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Rf 102 and Rf 103 may be the same or different. 1 is an integer from 0 to 5, and Rf 101 represents an organic group containing a fluorine atom.]

[0191] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. In formula (f1-1), Rf 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 103Examples 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, and a fluorine atom is particularly preferred. Among these, Rf 102 and Rf 103 is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group. In formula (f1-1), nf 1 is an integer of 0 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

[0192] In formula (f1-1), Rf 101 is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The fluorine atom-containing hydrocarbon group may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. Furthermore, in the fluorine atom-containing hydrocarbon group, preferably 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among them, Rf 101 is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a trifluoromethyl group, -CH2-CF3, -CH2-CF2-CF3, -CH(CF3)2, -CH2-CH2-CF3, or -CH2-CH2-CF2-CF2-CF2-CF3.

[0193] The weight-average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. When the Mw is below the upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, and when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.0 to 2.5.

[0194] In the resist composition according to an embodiment of the present invention, the component (F) may be used either as a single type, or in combination of two or more types. When the resist composition contains the component (F), the component (F) is typically used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

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

[0196] <Acid diffusion controller component (D)> In addition to the components (A), (B), and (F), the resist composition according to an embodiment of the present invention may further contain an acid diffusion controller component (component (D)) that traps the acid generated upon exposure (i.e., controls the diffusion of the acid). The component (D) acts as a quencher (acid diffusion controller) that traps the acid generated in the resist composition upon exposure. Examples of the component (D) include a photodegradable base (D1) (hereinafter referred to as "component (D1)") that decomposes upon exposure and loses its acid diffusion controllability, and a nitrogen-containing organic compound (D2) (hereinafter referred to as "component (D2)") that does not fall under the category of component (D1). Among these, the photodegradable base (D1) (component (D1)) is preferred from the viewpoint of resolution.

[0197] Regarding component (D1) By using a resist composition that contains the component (D1), the contrast between exposed and unexposed areas of the resist film can be further improved during resist pattern formation, thereby improving resolution. The component (D1) is not particularly limited as long as it decomposes upon exposure to light and loses its acid diffusion controllability, and may be a carboxylate, sulfonate, sulfonimide, or the like, with a carboxylate being preferred from the standpoint of quenching ability. As the (D1) component, for example, one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)") are preferred. The components (d1-1) to (d1-3) do not act as quenchers in the exposed areas of the resist film because they decompose and lose their acid diffusion control properties (basicity), but act as quenchers in the unexposed areas of the resist film.

[0198] [ka]

[0199] [In the formula, Rd 1 ~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. 2 In this case, no fluorine atom is bonded to the carbon atom adjacent to the S atom. 1 is a single bond or a divalent linking group; m is an integer of 1 or more; M m+ are each independently an m-valent organic cation.

[0200] {(d1-1) component} Anion part In formula (d1-1), Rd1 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of the R' 201 The same can be mentioned. Among these, Rd 1 is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Substituents which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5). Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (a polycyclic structure consisting of a bicyclooctane skeleton and another ring structure). The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, 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.

[0201] When the chain-like alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the number of carbon atoms in the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8, and even more preferably 1 to 4. The fluorinated alkyl group may contain atoms other than fluorine atoms. Examples of atoms other than fluorine atoms include oxygen atoms, sulfur atoms, and nitrogen atoms. Road 1 The alkyl group is preferably a fluorinated alkyl group in which some or all of the hydrogen atoms constituting a linear alkyl group have been substituted with fluorine atoms, and particularly preferably a fluorinated alkyl group in which all of the hydrogen atoms constituting a linear alkyl group have been substituted with fluorine atoms (linear perfluoroalkyl group).

[0202] Preferred examples of the anion moiety of the component (d1-1) are shown below.

[0203] [ka]

[0204] Cation part In formula (d1-1), M m+ is an m-valent organic cation. M m+ Suitable organic cations include those similar to those represented by the general formulae (ca-1) to (ca-3), with the cation represented by the general formula (ca-1) being more preferred, and the cations represented by the general formulae (ca-1-1) to (ca-1-68) being even more preferred. The component (d1-1) may be used alone or in combination of two or more.

[0205] {(d1-2) component} Anion part In formula (d1-2), Rd 2 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and R' 201The same can be mentioned. However, Rd 2 In this case, the carbon atom adjacent to the S atom is not bonded to a fluorine atom (is not fluorinated), which makes the anion of component (d1-2) an appropriately weak acid anion, thereby improving the quenching ability of component (D). Road 2 is preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10. The aliphatic cyclic group is more preferably a group (which may have a substituent) in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc.; or a group in which one or more hydrogen atoms have been removed from camphor, etc. Road 2 The hydrocarbon group may have a substituent, and the substituent may be Rd 1 Examples of the substituents include the same as those that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above.

[0206] Preferred examples of the anion moiety of the component (d1-2) are shown below.

[0207] [ka]

[0208] Cation part In formula (d1-2), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-2) may be used alone or in combination of two or more.

[0209] {(d1-3) component} Anion part In formula (d1-3), Rd 3is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and R' 201 The Rd is preferably a fluorine atom-containing cyclic group, a chain alkyl group, or a chain alkenyl group. Among these, a fluorinated alkyl group is preferred, and the Rd 1 The same fluorinated alkyl groups as those mentioned above are more preferred.

[0210] In formula (d1-3), Rd 4 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and R' 201 The same can be mentioned. Among these, alkyl groups, alkoxy groups, alkenyl groups and cyclic groups which may have a substituent are preferred. Road 4 The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. 4 A portion of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, or the like. Road 4 The alkoxy group in is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

[0211] Road 4 The alkenyl group in R' 201 Examples include the same alkenyl groups as those in the above, and vinyl, propenyl (allyl), 1-methylpropenyl, and 2-methylpropenyl groups are preferred. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

[0212] Road 4 The cyclic group in the formula (I) is the same as the R' 201 Examples of the cyclic group include the same as the cyclic group in the above, and preferred are alicyclic groups obtained by removing one or more hydrogen atoms from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane, or aromatic groups such as a phenyl group or a naphthyl group. 4 When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, resulting in excellent lithography properties. 4 When is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition exhibits excellent light absorption efficiency, and exhibits favorable sensitivity and lithography properties.

[0213] In formula (d1-3), Yd 1 is a single bond or a divalent linking group. Yd 1 The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. 21 Examples of the divalent linking group include the same divalent hydrocarbon groups which may have a substituent and divalent linking groups containing a hetero atom as those mentioned in the description of the divalent linking group in the above. Yd 1 is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0214] Preferred examples of the anion moiety of the component (d1-3) are shown below.

[0215] [ka]

[0216] [ka]

[0217] Cation part In formula (d1-3), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-3) may be used alone or in combination of two or more.

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

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

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

[0221] Manufacturing method of component (D1): The method for producing the components (d1-1) and (d1-2) is not particularly limited, and they can be produced by known methods. The method for producing component (d1-3) is not particularly limited, and it can be produced, for example, in a manner similar to that described in US2012-0149916.

[0222] Regarding component (D2) The component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the component (D1) described above. The component (D2) is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of component (D1), and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are particularly preferred. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms. Examples of aliphatic amines include amines in which at least one hydrogen atom of ammonia NH3 has been substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcoholamines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcoholamines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0223] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of the aliphatic monocyclic amine include piperidine and piperazine. The aliphatic polycyclic amine is preferably one having 6 to 10 carbon atoms, and specific examples thereof include 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0224] Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, and triethanolamine triacetate, with triethanolamine triacetate being preferred.

[0225] Furthermore, an aromatic amine may be used as the component (D2). Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, and N-tert-butoxycarbonylpyrrolidine.

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

[0227] The component (D2) may be used alone or in combination of two or more. When the resist composition contains the component (D2), the amount of the component (D2) within the resist composition is typically within a range from 0.005 to 5 parts by mass per 100 parts by mass of the component (A). By ensuring this range, the resist pattern shape and stability over time during storage can be improved.

[0228] <Organic solvent component (S)> The resist composition according to an embodiment of the present invention can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as “component (S)”). In the resist composition according to an embodiment of the present invention, the component (S) may be used either alone or as a mixed solvent of two or more different solvents. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0229] Furthermore, a mixed solvent of PGMEA and a polar solvent is also preferred as component (S), and the blending ratio (mass ratio) may be appropriately determined taking into consideration the compatibility between PGMEA and the polar solvent, etc. The component (S) is also preferably a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone, in which case the mass ratio of the former to the latter is preferably 70:30 to 95:5. There are no particular restrictions on the amount of component (S) used, and it is set appropriately depending on the coating film thickness so as to provide a concentration that allows application to a substrate, etc. Generally, the component (S) is used so that the solids concentration of the resist composition falls within the range of 0.1 to 20 mass %, and preferably 0.2 to 15 mass %.

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

[0231] In the resist composition according to an embodiment of the present invention, after dissolving the resist material in component (S), impurities may be removed using a polyimide porous film, a polyamideimide porous film, or the like. For example, the resist composition may be filtered using a filter made of a polyimide porous film, a filter made of a polyamideimide porous film, or a filter made of a polyimide porous film and a polyamideimide porous film. Examples of such polyimide porous films and polyamideimide porous films include those described in JP 2016-155121 A.

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

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

[0234] After the development process, a rinse process is preferably carried out. In the case of an alkaline development process, the rinse process is preferably a water rinse using pure water, and in the case of a solvent development process, it is preferable to use a rinse solution containing an organic solvent. In the case of a solvent development process, the developing treatment or rinsing treatment may be followed by a treatment of removing the developing solution or rinsing solution adhering to the pattern using a supercritical fluid. After the development treatment or rinsing treatment, the film is dried. In some cases, a baking treatment (post-baking) may be performed after the development treatment.

[0235] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those on which a predetermined wiring pattern is formed. More specifically, examples include silicon wafers, substrates made of metals such as copper, chromium, iron, and aluminum, and glass substrates. Materials that can be used for the wiring pattern include copper, aluminum, nickel, and gold.

[0236] The wavelength used for exposure is not particularly limited, and 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.

[0237] The exposure method for the resist film may be a normal exposure (dry exposure) carried out in air or an inert gas such as nitrogen, or may be liquid immersion lithography. Immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure device is filled with a solvent (immersion medium) that has a refractive index greater than that of air, and then exposure (immersion exposure) is performed in that state. The immersion medium is preferably a solvent having a refractive index greater than that of air and less than that of the resist film to be exposed, such as water, a fluorine-based inert liquid, a silicon-based solvent, or a hydrocarbon-based solvent. As the immersion medium, water is preferably used.

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

[0239] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

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

[0241] The organic developer may contain known additives as needed. Examples of such additives include surfactants. The surfactants are not particularly limited, but may include, for example, ionic or nonionic fluorine-based and / or silicon-based surfactants.

[0242] The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the surface of the support by surface tension and leaving it standing for a certain period of time (puddle method), a method of spraying the developer onto the surface of the support (spray method), or a method of continuously applying the developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0243] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be selected appropriately from the organic solvents listed above as organic solvents used in the organic developer, so long as it does not easily dissolve the resist pattern. Typically, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. These organic solvents may be used alone or in combination of two or more, and may be used in combination with other organic solvents or water.

[0244] The rinse treatment (cleaning treatment) using a rinse solution can be carried out by a known rinse method, such as a method of continuously applying the rinse solution onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse solution for a certain period of time (dipping method), or a method of spraying the rinse solution onto the surface of the support (spray method).

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

[0246] The resist composition of the above-described embodiment and the various materials used in the pattern formation method of the above-described embodiment (e.g., resist solvent, developer, rinse, anti-reflective coating composition, top coat composition, etc.) preferably do not contain impurities such as metals, halogen-containing metal salts, acids, alkalis, or components containing sulfur or phosphorus atoms. Examples of metal-containing impurities include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, and salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially free (below the detection limit of the measuring device). [Example]

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

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

[0249] [ka]

[0250] [Table 1]

[0251] [ka]

[0252] [ka]

[0253] [ka]

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

[0255] [Table 2]

[0256] [Table 3]

[0257] [Table 4]

[0258] In Tables 2 to 4, the abbreviations have the following meanings: A-1 to A-10: The above polymer compounds (A)-1 to (A)-10 A-X1 to A-X4: the above polymer compounds (A)-X1 to (A)-X4 B-1 to B-4: Acid generators composed of compounds represented by the following chemical formulas (B)-1 to (B)-4 D-1 to D-6: Acid diffusion controllers composed of compounds represented by the following chemical formulas (D)-1 to (D)-6 F-1: Hydrophobic resin F-1 containing the following structural unit (composition ratio (molar ratio): l / m = 80 / 20, Mw: 25000, Mw / Mn: 1.5)

[0259] [ka]

[0260] [ka]

[0261] [ka]

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

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

[0264] <Evaluation of Resist Pattern> [Evaluation of LWR (Line Width Roughness)] For the LS pattern formed by the above <Formation of Resist Pattern>, 3σ, a measure of LWR, was calculated. "3σ" indicates three times the standard deviation (σ) (unit: nm) obtained from the measurement results of 400 line positions measured in the longitudinal direction of the line using a critical dimension SEM (scanning electron microscope, accelerating voltage 500V, product name: CG5000, manufactured by Hitachi High-Technologies Corporation). The results are shown in Tables 2 to 4. The smaller the 3σ value, the less rough the line width, meaning that an LS pattern with a more uniform width was obtained.

[0265] [Evaluation of sensitivity (optimum exposure amount)] The optimum exposure dose for forming an LS pattern of the target size by the above resist pattern formation method is sensitivity (unit: mJ / cm 2 ) was calculated and shown in Tables 2 to 4 as sensitivity.

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

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

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, The photosensitive resin composition contains a base component (A) whose solubility in a developer changes under the action of an acid, an acid generator component (B) that generates an acid upon exposure, and a fluorine additive component (F), The base component (A) comprises a structural unit (a1) represented by the following general formula (a1-1), and a lactone-containing cyclic group represented by the following general formula (a2-1), —SO ２ a polymeric compound (A1) having a structural unit (a2) containing either a cyclic group-containing group or a carbonate-containing cyclic group, Resist composition. 【Chemistry 1】 In general formula (a1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １１ represents a cyclic hydrocarbon group having 5 to 8 carbon atoms, and n represents an integer of 1 to 3. 【Chemistry 2】 In general formula (a2-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ２１ represents a single bond or a divalent linking group. ２１ represents -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. ２１ When is -O-, Ya ２１ does not become -CO-. ２１ is a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ represents a -containing cyclic group.]

2. The Ra in the general formula (a2-1) ２１ The resist composition according to claim 1, wherein: is a substituent represented by any one of the following formulas (a2-r-1) to (a2-r-7): 【Transformation 3】 [In formulas (a2-r-1) to (a2-r-7), Ra' ２１ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group, or a cyano group; R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or —SO ２ A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (-O-) or a sulfur atom (-S-), an oxygen atom, or a sulfur atom, n' is an integer of 0 to 2, and m' is 0 or 1. * represents a bond.

3. 3. The resist composition according to claim 1, wherein the fluorine additive component (F) comprises a polymer having a structural unit (f1) represented by the following general formula (f1-1): 【Chemistry 4】 In general formula (f1-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. １０２ and Rf １０３ Rf each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; １０２ and Rf １０３ may be the same or different. １ is an integer of 0 to 5, and Rf １０１ represents an organic group containing a fluorine atom.]

4. 3. The resist composition according to claim 1, further comprising an acid diffusion controller component (D) that controls the diffusion of the acid generated from the acid generator component (B) upon exposure.

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

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