Resist composition and method for forming a resist pattern

Abstract

To provide a resist composition having good sensitivity, good LWR performance and good defect resistance in a well-balanced manner, and a resist pattern forming method using the resist composition.SOLUTION: The resist composition contains a base component (A), an acid generator component (B), and an acid diffusion control agent (D) which controls diffusion of an acid generated from the acid generator component (B) upon exposure. The acid generator component (B) contains an acid generator (B1) having a group represented by the following formula (b1-1) in an anionic moiety, and an acid generator (B2) different from (B1). The acid diffusion control agent (D) contains a photodegradable base (D0) having a group represented by the following formula (d0) in an anionic moiety and does not contain a nitrogen-containing organic compound (D2). In the formula (d0), Rb1 represents an optionally substituted hydrocarbon group, provided that Rb1 does not contain a halogen atom.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resist composition and a method of forming a resist pattern. This application claims priority based on Korean Patent Application No. 10-2020-0111254, filed in the Republic of Korea on September 1, 2020, the contents of which are incorporated herein by reference. [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.

[0003] In recent years, advances in lithography technology have led to rapid progress in miniaturization of patterns in the manufacture of semiconductor elements and liquid crystal display elements. A common method of miniaturization is to shorten the wavelength (increase the energy) of the exposure light source. Specifically, while ultraviolet rays such as g-line and i-line have traditionally been used, KrF excimer lasers and ArF excimer lasers are now being used in the mass production of semiconductor elements. 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.

[0004] Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with minute dimensions. To satisfy these requirements, a chemically amplified resist composition has been used, which contains a base component whose solubility in a developer changes due to the action of acid, and an acid generator component that generates acid upon exposure.

[0005] For example, when the developer is an alkaline developer (alkaline development process), a positive chemically amplified resist composition generally contains a resin component (base resin) whose solubility in the alkaline developer increases under the action of acid, and an acid generator component. When a resist film formed using such a resist composition is subjected to selective exposure during resist pattern formation, acid is generated from the acid generator component in the exposed areas, and the polarity of the base resin increases due to the action of the acid, making the exposed areas of the resist film soluble in the alkaline developer. Therefore, alkaline development forms a positive pattern in which the unexposed areas of the resist film remain as a pattern.

[0006] On the other hand, when such a chemically amplified resist composition is applied to a solvent development process using a developer containing an organic solvent (organic developer), as the polarity of the base resin increases, its solubility in the organic developer decreases relatively, so that the unexposed areas of the resist film are dissolved and removed by the organic developer, forming a negative resist pattern in which the exposed areas of the resist film remain as a pattern. This solvent development process that forms a negative resist pattern is sometimes called a negative development process.

[0007] The base resin used in a chemically amplified resist composition generally has a plurality of structural units in order to improve lithography properties and the like. For example, in the case of a resin component whose solubility in an alkaline developer increases due to the action of an acid, a structural unit containing an acid-decomposable group that decomposes due to the action of an acid generated from an acid generator or the like and thereby increases its polarity is used, and other structural units that include a lactone-containing cyclic group and structural units that include a polar group such as a hydroxyl group are also used in combination.

[0008] In the formation of a resist pattern, the behavior of the acid generated from the acid generator component upon exposure is considered to be one factor that has a significant effect on lithography properties. A wide variety of acid generators have been proposed for use in chemically amplified resist compositions, including, for example, onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators. Onium salt acid generators that are mainly used have an onium ion such as triphenylsulfonium in the cation moiety, and the anion moiety of these onium salt acid generators generally includes an alkylsulfonate ion or a fluorinated alkylsulfonate ion in which some or all of the hydrogen atoms in the alkyl group are substituted with fluorine atoms.

[0009] In recent years, the miniaturization of resist patterns has been progressing at an increasing rate, and conventional resist compositions are being required to be able to form resist patterns with good shapes during resist pattern formation, as well as to further improve various lithography properties.

[0010] For this reason, such resist compositions are required to not only exhibit excellent resist pattern resolution and cross-sectional rectangularity, but also excellent LWR (Line Width Roughness) performance, CDU (Critical Dimension Uniformity) performance, EL (Exposure Latitude) performance, development defect suppression, and film shrinkage suppression after PEB (Post Exposure Bake). Resist compositions are also required to have good storage stability. To meet these requirements, the types and molecular structures of acid generators, acid diffusion controllers, and other components used in resist compositions have been studied in detail. However, as resist patterns have now been miniaturized to the level of line widths of 45 nm or less, the level of performance required is becoming even higher, and the conventional resist compositions described above are unable to meet these requirements.

[0011] In order to improve various lithography properties in the formation of resist patterns, radiation-sensitive resin compositions containing a polymer having an acid-dissociable group, a sulfonate having a specific structure, and a solvent, as well as resist compositions containing other types of acid generators have also been proposed (see, for example, Patent Document 1).

[0012] However, when patterns were formed using conventional resist compositions, it was not possible to sufficiently achieve both good LWR performance and good improvement in defect tolerance, and therefore it was necessary to achieve both at a higher level. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-244352 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a resist composition that exhibits a good balance of good sensitivity, good LWR performance, and good defect resistance, as well as a method of forming a resist pattern using the resist composition. [Means for solving the problem]

[0015] As a result of intensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a resist composition that contains an acid generator having a specific group in its anion moiety, an acid generator different from the above-mentioned acid generator, and a photodegradable base having a specific group in its anion moiety, and that does not contain a nitrogen-containing organic compound as an acid diffusion controller, and have thus completed the present invention.

[0016] The present invention includes the following aspects. [1] A resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, a base component (A) whose solubility in a developer changes under the action of an acid; an acid generator component (B) that generates acid upon exposure to light, and an acid diffusion controller (D) that controls the diffusion of the acid generated from the acid generator component (B) upon exposure; the acid generator component (B) includes an acid generator (B1) having a group represented by the following formula (b1-1) at the anion moiety, and an acid generator (B2) different from (B1): The resist composition is characterized in that the acid diffusion controller (D) contains a photodegradable base (D0) having a group represented by the following formula (d0) in the anion moiety, and does not contain a nitrogen-containing organic compound (D2):

[0017] [ka]

[0018] [ka] [In the formula, Rb 1 represents a hydrocarbon group which may have a substituent, provided that Rb 1 does not contain halogen atoms.

[0019] [2] The resist composition according to the above item [1], wherein the acid generator (B2) is selected from the group consisting of a compound represented by the following formula (b-1), a compound represented by the following formula (b-2), and a compound represented by the following formula (b-3), with the proviso that the compound represented by formula (b-2) does not have a group represented by formula (b1-1) in its anion moiety.

[0020] [ka] [In the formula, R 101 , R 104 ~R 108 R are each independently a halogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.104 , R 105 may be bonded to each other to form a ring. 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 101 is a single bond or a divalent linking group containing an oxygen atom. 101 ~V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group. 101 ~L 102 are each independently a single bond or an oxygen atom. 103 ~L 105 are each independently a single bond, —CO— or —SO2—; m is an integer of 1 or more; and M' m+ is an m-valent onium cation.

[0021] [3] The resist composition according to the above [1] or [2], wherein the group represented by the formula (d0) is selected from the groups represented by the following formulae (d0-1) to (d0-23):

[0022] [ka]

[0023] [4] The resist composition according to any one of the above [1] to [3], further comprising an additive (E). [5] The resist composition according to any one of the above [1] to [4], further comprising a fluorine additive (F). [6] A method for forming a resist pattern, comprising the steps of: forming a resist film on a support using the resist composition according to any one of the above items [1] to [5]; exposing the resist film; and developing the exposed resist film using a developer. [Effects of the Invention]

[0024] According to the present invention, it is possible to provide a resist composition that exhibits a good balance of good sensitivity, good LWR performance, and good defect resistance, as well as a method of forming a resist pattern using the resist composition. DETAILED DESCRIPTION OF THE INVENTION

[0025] In this specification and claims, the term "aliphatic" is defined as a relative concept to aromatic, and refers to groups, compounds, etc. that do not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes straight-chain, branched-chain 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.

[0026] 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. α0 ) is substituted with a substituent containing an ester bond, or α0 The term also includes α-hydroxyacrylic esters in which the α-hydroxy group is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom has been replaced with a substituent may be referred to as an α-substituted acrylic ester. Furthermore, acrylic esters and α-substituted acrylic esters may be collectively referred to as "(α-substituted) acrylic esters." The term "structural unit derived from acrylamide" refers to a structural unit formed by cleavage of the ethylenic double bond of acrylamide. In acrylamide, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, or one or both of the hydrogen atoms of the amino group of the acrylamide may be substituted with a substituent. Note that the carbon atom at the α-position of the acrylamide refers to the carbon atom to which the carbonyl group of the acrylamide is bonded, unless otherwise specified. The substituents that substitute the hydrogen atom bonded to the carbon atom at the α-position of the acrylamide include those exemplified as the substituents at the α-position in the above α-substituted acrylic ester (substituent (R α0 )) and similar examples are listed. The term "structural unit derived from hydroxystyrene or a hydroxystyrene derivative" refers to a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene or a hydroxystyrene derivative. The term "hydroxystyrene derivative" encompasses hydroxystyrenes in which the hydrogen atom at the α-position is substituted with other substituents such as alkyl groups or halogenated alkyl groups, as well as derivatives thereof. Examples of such derivatives include hydroxystyrenes in which the hydrogen atom at the α-position may be substituted with a substituent, but the hydrogen atom of the hydroxyl group is substituted with an organic group; and hydroxystyrenes in which the hydrogen atom at the α-position may be substituted with a substituent, but a substituent other than a hydroxyl group is bonded to the benzene ring. Unless otherwise specified, the α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded. Examples of the substituent that substitutes the hydrogen atom at the α-position of the hydroxystyrene include the same groups as those exemplified as the substituent at the α-position in the above α-substituted acrylic ester.

[0027] The term "structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative" refers to a structural unit formed by cleavage of the ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative. The term "vinylbenzoic acid derivative" encompasses compounds in which the hydrogen atom at the α-position of vinylbenzoic acid is substituted with another substituent, such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of the carboxy group of vinylbenzoic acid, which may have the hydrogen atom at the α-position substituted with a substituent, is substituted with an organic group; compounds in which a substituent other than a hydroxyl group or a carboxy group is bonded to the benzene ring of vinylbenzoic acid, which may have the hydrogen atom at the α-position substituted with a substituent; and the like. Unless otherwise specified, the α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded. The term "styrene" is intended to encompass styrene and styrene in which the hydrogen atom at the α-position has been substituted with another substituent such as an alkyl group or a halogenated alkyl group. The term "styrene derivative" encompasses styrene in which the hydrogen atom at the α-position is substituted with another substituent, such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include styrene in which the hydrogen atom at the α-position may be substituted with a substituent, but in which a substituent is bonded to the benzene ring. Unless otherwise specified, the α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded. The terms "structural unit derived from styrene" and "structural unit derived from a styrene derivative" refer to a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative. 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. In this specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms, and may have enantiomers or diastereomers, but in such cases, a single formula represents all of the isomers. These isomers may be used alone or as a mixture.

[0028] (Resist composition) The resist composition of the present invention generates an acid upon exposure, and the solubility in a developer changes due to the action of the acid. One embodiment of such a resist composition includes a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of acid, an acid generator component (B) (hereinafter also referred to as "component (B)") that generates acid upon exposure, and an acid diffusion controller (D) (hereinafter also referred to as "component (D)"). In the resist composition of this embodiment, the component (B) includes an acid generator (B1) having a group represented by formula (b1-1) in its anion moiety, and an acid generator (B2) different from (B1), and the component (D) includes a photodegradable base (D0) having a group represented by formula (d0) in its anion moiety, but does not include a nitrogen-containing organic compound (D2).

[0029] When a resist film is formed using the resist composition of this embodiment and then subjected to selective exposure, an acid is generated from component (B) in the exposed areas of the resist film, and the solubility of component (A) in a developer changes due to the action of the acid, whereas the solubility of component (A) in a developer does not change in the unexposed areas of the resist film, resulting in a difference in solubility in a developer between the exposed and unexposed areas. Therefore, when the resist film is developed, if the resist composition is positive, the exposed areas of the resist film are dissolved and removed, forming a positive resist pattern, whereas if the resist composition is negative, the unexposed areas of the resist film are dissolved and removed, forming a negative resist pattern. In this specification, a resist composition that forms a positive resist pattern by dissolving and removing exposed portions of a resist film is referred to as a positive resist composition, and a resist composition that forms a negative resist pattern by dissolving and removing unexposed portions of a resist film is referred to as a negative resist composition.

[0030] 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.

[0031] The resist composition of this embodiment has an acid generating ability that generates an acid upon exposure, and in addition to the component (B), the component (A) may also generate an acid upon exposure. When component (A) generates an acid upon exposure, this component (A) becomes "a base component that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid." When the component (A) is a base component that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, it 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. Examples of such polymeric compounds include resins having a structural unit that generates an acid upon exposure. Known monomers can be used to derive the structural unit that generates an acid upon exposure.

[0032] <Component (A)> The component (A) is a base component whose solubility in a developer changes under the action of an acid. In the present invention, the "base component" refers to an organic compound having film-forming ability, and preferably has a molecular weight of at least 500. When the molecular weight of the organic compound is at least 500, the film-forming ability is improved, and in addition, nano-level resist patterns can be easily formed. The organic compounds used as the base material component are broadly classified into non-polymers and polymers. The non-polymers typically have a molecular weight of 500 or more and less than 4000. Hereinafter, the term "low molecular weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000. The polymer typically used has a molecular weight of 1000 or more. Hereinafter, the term "resin" or "polymer compound" refers to a polymer with a molecular weight of 1000 or more. The molecular weight of the polymer is determined by gel permeation chromatography (GPC) and is expressed as polystyrene equivalent weight average molecular weight.

[0033] When the resist composition of this embodiment is a "negative resist composition for alkaline development processes" that forms a negative resist pattern in an alkaline development process, or a "positive resist composition for solvent development processes" that forms a positive resist pattern in a solvent development process, the component (A) preferably uses a base component that is soluble in an alkaline developer, and also contains a crosslinker component. In such a resist composition, for example, when an acid is generated from component (B) upon exposure, the acid acts to cause crosslinking between the base component and the crosslinker component, resulting in a decrease in solubility in alkaline developers (and an increase in solubility in organic developers). Therefore, in forming a resist pattern, when the resist film obtained by applying the resist composition to a support is selectively exposed, the exposed portions of the resist film become poorly soluble in an alkaline developer (soluble in an organic developer), while the unexposed portions of the resist film remain soluble in an alkaline developer (poorly soluble in an organic developer), so that development with an alkaline developer forms a negative resist pattern. At the same time, development with an organic developer forms a positive resist pattern.

[0034] In a negative resist composition, a resin that is soluble in an alkaline developer (hereinafter referred to as an "alkali-soluble resin") is preferably used as the base component. Examples of alkali-soluble resins that can form good resist patterns with little swelling include resins having a structural unit derived from at least one selected from α-(hydroxyalkyl)acrylic acid or alkyl esters of α-(hydroxyalkyl)acrylic acid (preferably alkyl esters having 1 to 5 carbon atoms), as disclosed in JP 2000-206694 A; acrylic resins or polycycloolefin resins having a sulfonamide group, in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, as disclosed in U.S. Patent No. 6,949,325 A; acrylic resins containing a fluorinated alcohol, in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, as disclosed in U.S. Patent No. 6,949,325 A, JP 2005-336452 A, and JP 2006-317803 A; and polycycloolefin resins containing a fluorinated alcohol, as disclosed in JP 2006-259582 A. The above-mentioned α-(hydroxyalkyl)acrylic acid refers to one or both of acrylic acid in which a hydrogen atom bonded to the carbon atom at the α-position to which a carboxy group is bonded, and α-hydroxyalkylacrylic acid in which a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 5 carbon atoms) is bonded to the carbon atom at the α-position, among acrylic acids in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. As the crosslinking agent component, it is preferable to use, for example, an amino-based crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group, or a melamine-based crosslinking agent, etc., since this facilitates the formation of a good resist pattern with little swelling. The blending amount of the crosslinking agent component is preferably 1 to 50 parts by mass per 100 parts by mass of the alkali-soluble resin.

[0035] When the resist composition of this embodiment is a "positive resist composition for use in an alkaline development process" that forms a positive resist pattern in an alkaline development process, or a "negative resist composition for use in a solvent development process" that forms a negative resist pattern in a solvent development process, the component (A) preferably uses a base component (A') (hereafter referred to as "component (A')") whose polarity increases under the action of acid. By using component (A'), the polarity of the base component changes before and after exposure, and therefore good development contrast can be obtained not only in alkaline development processes but also in solvent development processes.

[0036] When an alkaline development process is applied, the component (A') is poorly soluble in an alkaline developer before exposure, and when, for example, an acid is generated from the component (B) upon exposure, the polarity increases due to the action of the acid, thereby increasing the solubility in the alkaline developer. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the exposed areas of the resist film change from being poorly soluble in an alkaline developer to being soluble, while the unexposed areas of the resist film remain poorly soluble in alkali, and therefore a positive resist pattern is formed by alkaline development.

[0037] On the other hand, when a solvent development process is applied, the component (A') is highly soluble in organic developers before exposure, but when an acid is generated from the component (B) upon exposure, the acid increases the polarity and reduces the solubility in organic developers. Therefore, in forming a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed to light, the exposed areas of the resist film change from soluble to sparingly soluble in organic developers, while the unexposed areas of the resist film remain soluble. Therefore, by developing with an organic developer, a contrast can be created between the exposed and unexposed areas, and a negative resist pattern can be formed.

[0038] In the resist composition of this embodiment, the component (A) is preferably the above-mentioned component (A'). In other words, the resist composition of this embodiment is preferably a "positive resist composition for use in an alkaline development process" that forms a positive resist pattern in an alkaline development process, or a "negative resist composition for use in a solvent development process" that forms a negative resist pattern in a solvent development process.

[0039] The component (A) may be a high molecular weight compound and / or a low molecular weight compound. When the component (A) is the component (A'), the component (A') preferably contains a polymeric compound, and more preferably contains a polymeric compound (A1) (hereinafter also referred to as "component (A1)") having a structural unit (a1) containing an acid-decomposable group whose polarity increases upon the action of acid.

[0040] As the component (A1), it is preferable to use a polymeric compound that has, in addition to the structural unit (a1), a structural unit (a2) that includes a lactone-containing cyclic group, an —SO 2 —-containing cyclic group, or a carbonate-containing cyclic group. Furthermore, as the component (A1), it is also preferable to use a polymeric compound that has, in addition to the structural unit (a1), or in addition to the structural unit (a1) and the structural unit (a2), a structural unit (a3) ​​that contains a polar group-containing aliphatic hydrocarbon group (provided that this does not correspond to the structural unit (a1) or the structural unit (a2)). In addition to the structural units (a1) to (a3), the component (A1) may also include a structural unit (a4) containing an acid-non-dissociable aliphatic cyclic group, a structural unit that generates acid upon exposure, and the like.

[0041] <Constituent unit (a1)> The structural unit (a1) is a structural unit that contains an acid-decomposable group whose polarity increases upon the action of an acid. 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.

[0042] More specific examples of the acid-decomposable group include groups in which the above polar groups are protected with acid-dissociable groups (for example, groups in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group). 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.

[0043] Examples of the acid-dissociable group include those groups that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed for use in base resins for chemically amplified resist compositions include the "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," and "tertiary alkyloxycarbonyl acid-dissociable groups," which are described below.

[0044] ·Acetal type acid dissociable group: Among the polar groups, examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter sometimes referred to as "acetal-type acid-dissociable groups").

[0045] [ka] [In the formula, RA' 1 , RA' 2 is a hydrogen atom or an alkyl group, and RA' 3 is a hydrocarbon group, and RA' 3 RA' 1 , RA' 2 may be bonded to any one of the following to form a ring.]

[0046] In formula (a1-r-1), RA' 1 and RA' 2 At least one of these is preferably a hydrogen atom, and both are more preferably hydrogen atoms. RA' 1 or RA' 2 When is an alkyl group, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester above, with alkyl groups having 1 to 5 carbon atoms being preferred. Specific examples include linear or branched alkyl groups. More specific examples include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups, with methyl and ethyl being more preferred, and methyl being particularly preferred.

[0047] In formula (a1-r-1), RA' 3 Examples of the hydrocarbon group include a linear or branched alkyl group and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred. The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0048] RA' 3 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0049] RA' 3 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be either monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12.

[0050] Specific examples of aromatic rings include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon rings are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. RA' 3 Specific examples of the aromatic hydrocarbon group in include groups in which one hydrogen atom has been removed from the above-mentioned aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group); groups in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of the above-mentioned aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The number of carbon atoms in the alkylene group bonded to the above-mentioned aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1. RA' 3 But, RA' 1 , RA' 2 When the cyclic group is bonded to any of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0051] Tertiary alkyl ester-type acid-labile group: Among the polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2). Among the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group may be referred to as "tertiary alkyl ester-type acid-dissociable groups" hereinafter for convenience.

[0052] [ka] [In the formula, RA' 4 ~RA' 6 are hydrocarbon groups, and RA' 5 , RA' 6 may be bonded to each other to form a ring.

[0053] RA' 4 ~RA' 6 The hydrocarbon group of the above RA' 3 The same can be mentioned. RA' 4 is preferably an alkyl group having 1 to 5 carbon atoms. 5 and RA' 6 When R A' and R B' are bonded to each other to form a ring, examples of the ring include groups represented by the following general formula (a1-r2-1). 4 ~RA' 6 When the groups are not bonded to each other and are independent hydrocarbon groups, examples thereof include groups represented by the following general formula (a1-r2-2).

[0054] [ka] [In the formula, RA' 10 is an alkyl group having 1 to 10 carbon atoms, RA' 11 RA' 10 a group forming an aliphatic cyclic group together with the carbon atom to which RA' is attached; 12 ~RA' 14 each independently represents a hydrocarbon group.

[0055] In formula (a1-r2-1), RA' 10 The alkyl group having 1 to 10 carbon atoms is represented by RA' in the formula (a1-r-1). 3 In formula (a1-r2-1), the groups exemplified as the linear or branched alkyl group are preferred. 11 But, RA' 10 The aliphatic cyclic group formed together with the carbon atom to which is bonded is RA' in formula (a1-r-1). 3 The groups mentioned above as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups.

[0056] In formula (a1-r2-2), RA' 12 and RA' 14 are each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is preferably R A' in formula (a1-r-1). 3 More preferred are the groups exemplified as linear or branched alkyl groups of the above, further preferred are linear alkyl groups having 1 to 5 carbon atoms, and particularly preferred are methyl or ethyl groups.

[0057] In formula (a1-r2-2), RA' 13 is RA' in formula (a1-r-1) 3 Among these, the aliphatic hydrocarbon groups RA' are preferably linear or branched alkyl groups, monocyclic groups, or polycyclic groups exemplified as the hydrocarbon groups of RA'. 3 More preferably, the aliphatic hydrocarbon group is a monocyclic or polycyclic group as exemplified above.

[0058] Specific examples of the group represented by the above formula (a1-r2-1) are listed below: * represents a bond (the same applies hereinafter in this specification).

[0059] [ka]

[0060] [ka]

[0061] Specific examples of the group represented by the above formula (a1-r2-2) are listed below.

[0062] [ka]

[0063] Tertiary alkyloxycarbonyl acid dissociating group: Among the above polar groups, examples of the acid-dissociable group that protects the hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience, may be referred to as "tertiary alkyloxycarbonyl acid-dissociable group").

[0064] [ka] [In the formula, RA' 7 ~RA' 9 are each an alkyl group.

[0065] In formula (a1-r-3), RA' 7 ~RA' 9 is preferably an alkyl group having 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms. The total number of carbon atoms in each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 or 4.

[0066] Examples of the structural unit (a1) include a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, a structural unit derived from acrylamide, a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least a portion of the hydrogen atoms in the hydroxyl groups are protected with an acid-dissociable group, and a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative in which at least a portion of the hydrogen atoms in -C(═O)-OH are protected with an acid-dissociable group.

[0067] Of the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. Preferred specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1) or (a1-2).

[0068] [ka] [wherein 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. 1 is a divalent hydrocarbon group which may have an ether bond, and n a1 is 0 to 2, and Ra 1 is an acid-dissociable group represented by the above formula (a1-r-1) or (a1-r-2). 1 is n a2 + is a monovalent hydrocarbon group, n a2 is 1 to 3, and Ra 2 is an acid-dissociable group represented by the above formula (a1-r-1) or (a1-r-3).

[0069] In the above formula (a1-1), the alkyl group of R having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, 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.

[0070] In the above formula (a1-1), Va 1 The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Va 1 The aliphatic hydrocarbon group as the divalent hydrocarbon group in may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in its structure. The linear or branched 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.

[0071] 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 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-; alkyltrimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyltetramethylene 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. Examples of the aliphatic hydrocarbon group containing a ring in the structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as the straight-chain aliphatic hydrocarbon group or the branched-chain aliphatic hydrocarbon group.

[0072] The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0073] Va 1 The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such aromatic hydrocarbon groups preferably have 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group (arylene group) in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring; a group (aryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring, and one hydrogen atom of the group (aryl group) in which one hydrogen atom has been substituted with an alkylene group (for example, a group in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group, such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0074] In the above formula (a1-2), Wa 1 n in a2 The monovalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in their structure, and groups that combine linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in their structure. Above n a2 The +1 valence is preferably 2 to 4, more preferably 2 or 3.

[0075] Specific examples of the structural unit represented by the above formula (a1-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] Specific examples of the structural unit represented by the above formula (a1-2) are shown below.

[0082] [ka]

[0083] The structural unit (a1) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a1) in the component (A1) relative to the total of all structural units constituting the component (A1) is preferably 5 to 60 mol %, more preferably 10 to 55 mol %, and even more preferably 20 to 50 mol %. By ensuring that the proportion of the structural unit (a1) is at least as large as the lower limit, a resist pattern can be easily obtained, and lithography properties such as sensitivity, resolution, roughness improvement, and EL margin can be improved. Furthermore, by ensuring that the proportion is at most the upper limit, a balance with other structural units can be achieved.

[0084] <Constituent unit (a2)> The structural unit (a2) is a structural unit that includes a lactone-containing cyclic group, an -SO2- containing cyclic group, or a carbonate-containing cyclic group (however, this does not include those that fall under the category of the structural unit (a1)). The lactone-containing cyclic group, -SO2- containing cyclic group, or carbonate-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate when the component (A1) is used to form a resist film. Furthermore, in an alkaline development process, the presence of the structural unit (a2) increases the solubility of the resist film in an alkaline developer during development.

[0085] A "lactone-containing cyclic group" refers to a cyclic group that contains a ring (lactone ring) containing -OC(=O)- in its ring skeleton. The lactone ring is counted as the first ring, and when there is only a lactone ring, it is called a monocyclic group. When there is additional ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

[0086] The lactone-containing cyclic group in the structural unit (a2) is not particularly limited and any suitable group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0087] [ka] [In the formula, RA' 21 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, 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.

[0088] In the above 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.

[0089] RA' 21 The alkoxy group in the formula (I) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group 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—).

[0090] RA' 21Examples 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 (I) is the same as the above-mentioned RA'. 21 Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the above-mentioned halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0091] 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.

[0092] 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.

[0093] Examples of the lactone-containing cyclic group in R″ include the same groups as those represented by the above general formulae (a2-r-1) to (a2-r-7).

[0094] The carbonate-containing cyclic group for R″ is the same as the carbonate-containing cyclic group described below, and specific examples include groups represented by general formulae (ax3-r-1) to (ax3-r-3).

[0095] 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 formulas (a5-r-1) to (a5-r-4).

[0096] RA' 21 The hydroxyalkyl group in the formula (I) preferably has 1 to 6 carbon atoms, and specifically, the ... 21 In the above formula, at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0097] In the above 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 inserted 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.

[0098] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are listed below.

[0099] [ka]

[0100] [ka]

[0101] 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.

[0102] More specific examples of the —SO2—-containing cyclic group include groups represented by the following general formulae (a5-r-1) to (a5-r-4).

[0103] [ka] [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.

[0104] In the above general formulae (a5-r-1) and (a5-r-2), A" is the same as A" in the above general formulae (a2-r-2), (a2-r-3), and (a2-r-5). RA' 51The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the above formula (a2-r-1) to (a2-r-7) are each RA' 21 Examples of the above include those mentioned in the explanation of the above.

[0105] Specific examples of the groups represented by general formulae (a5-r-1) to (a5-r-4) are listed below, in which "Ac" represents an acetyl group.

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] The term "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -OC(=O)-O- in its ring skeleton. Counting the carbonate ring as the first ring, a group containing only a carbonate ring is called a monocyclic group, while a group containing other ring structures is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.

[0110] The carbonate ring-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following general formulae (ax3-r-1) to (ax3-r-3).

[0111] [ka] [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.

[0112] In the above general formulae (ax3-r-2) to (ax3-r-3), A" is the same as A" in the above general formulae (a2-r-2), (a2-r-3), and (a2-r-5).

[0113] RA' 31 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the above formula (a2-r-1) to (a2-r-7) are each RA' 21 Examples of the above include those mentioned in the explanation of the above.

[0114] Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are listed below.

[0115] [ka]

[0116] Of these, the structural unit (a2) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Such a structural unit (a2) is preferably a structural unit represented by the following general formula (a2-1).

[0117] [ka] [In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.] 21 is a single bond or a divalent linking group. 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 is a lactone-containing cyclic group, a carbonate-containing cyclic group, or an —SO—-containing cyclic group.

[0118] In the above formula (a2-1), R is the same as above. Ya 21 The divalent linking group is not particularly limited, but preferred examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0119] 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 or an aromatic hydrocarbon group.

[0120] Ya 21 Aliphatic hydrocarbon groups in The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

[0121] Linear or branched aliphatic hydrocarbon groups The linear or branched 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 is preferably a branched alkylene group, and specific examples thereof include 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-; alkyltrimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyltetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms. The 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.

[0122] 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 above-mentioned 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 above-mentioned cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the above-mentioned 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 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.

[0123] The cyclic aliphatic hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl groups mentioned above have been substituted with the halogen atoms mentioned above. 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-.

[0124] Ya 21 Aromatic hydrocarbon groups in The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

[0125] Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the above-mentioned aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the above-mentioned aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The number of carbon atoms in the alkylene group bonded to the above-mentioned aryl group or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0126] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituents that substitute for the hydrogen atoms of the cyclic aliphatic hydrocarbon group.

[0127] Divalent linking groups containing heteroatoms: Ya 21 is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -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.

[0128] 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 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

[0129] General formula-Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or-Y 21 -S(=O)2-OY 22 -Medium, Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same groups as those (divalent hydrocarbon groups which may have a substituent) listed above in the description of the divalent linking group.

[0130] 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.

[0131] 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.

[0132] 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 22Among them, 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.

[0133] 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.

[0134] 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 Preferred examples of the lactone-containing cyclic group, the —SO—-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). Among these, lactone-containing cyclic groups or -SO2-containing cyclic groups are preferred, and groups represented by the above general formulas (a2-r-1), (a2-r-2), (a2-r-6), or (a5-r-1) are more preferred. Specifically, groups represented by the above general formulas (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) are more preferred.

[0135] 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 of all structural units constituting the component (A1) is preferably 1 to 80 mol %, more preferably 10 to 70 mol %, even more preferably 10 to 65 mol %, and particularly preferably 10 to 60 mol %. By ensuring that the proportion of the structural unit (a2) is at least as large as the preferred lower limit, the effects of including the structural unit (a2) can be fully obtained. On the other hand, by ensuring that the proportion is no more than the preferred upper limit, a balance with other structural units can be achieved, resulting in various favorable lithography properties and pattern shapes.

[0136] <Constituent unit (a3)> The structural unit (a3) ​​is a structural unit that contains a polar group-containing aliphatic hydrocarbon group (however, this does not apply to structural units (a1) or (a2)). By including the structural unit (a3) ​​in the component (A1), the hydrophilicity of the component (A1) is enhanced, which contributes to improving resolution.

[0137] 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.

[0138] Examples of the aliphatic hydrocarbon group 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 ArF excimer laser resist compositions, for example. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms. Among these, structural units derived from acrylate esters containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxyl 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.

[0139] 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. The structural unit (a3) ​​is a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and a structural unit containing a polar group-containing aliphatic hydrocarbon group is preferred.

[0140] When the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a straight-chain or branched-chain 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. When the hydrocarbon group is a polycyclic group, preferred structural units include those represented by the following formulas (a3-1), (a3-2), and (a3-3).

[0141] [ka] [In the formula, R is the same as 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 1 to 5, and s is an integer of 1 to 3.]

[0142] 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 3- and 5-positions of the adamantyl group. When j is 1, the hydroxyl group is preferably bonded to the 3-position of the adamantyl group. It is preferable that j is 1, and it is particularly preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.

[0143] In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5- or 6-position of the norbornyl group.

[0144] 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.

[0145] 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 of all structural units constituting the component (A1) is preferably 5 to 50 mol %, more preferably 5 to 40 mol %, and even more preferably 5 to 35 mol %. By ensuring that the proportion of the structural unit (a3) ​​is at least as large as the preferred lower limit, the effects of including the structural unit (a3) ​​can be fully obtained, while by ensuring that the proportion is at most the preferred upper limit, it becomes easier to achieve a balance with other structural units.

[0146] <Constituent unit (a4)> The structural unit (a4) is a structural unit that contains an acid-non-dissociable aliphatic cyclic group. By including the structural unit (a4) in the component (A1), the dry etching resistance of the formed resist pattern is improved. Additionally, the hydrophobicity of the component (A1) is enhanced. This improved hydrophobicity is believed to contribute to improvements in resolution, resist pattern shape, and the like, particularly in solvent development processes.

[0147] The “acid-non-dissociable cyclic group” within the structural unit (a4) is a cyclic group that, when acid is generated in the resist composition upon exposure (for example, when acid is generated from the component (B) described below), does not dissociate even when acted upon by the acid, and remains intact within the structural unit.

[0148] Preferred examples of the structural unit (a4) include structural units derived from acrylate esters that contain an acid-non-dissociable aliphatic cyclic group. The cyclic group can be any of the many conventionally known resin components used in resist compositions for ArF excimer lasers, KrF excimer lasers (preferably ArF excimer lasers), and the like. In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferred in terms of industrial availability, etc. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

[0149] Specific examples of the structural unit (a4) include structural units represented by the following general formulas (a4-1) to (a4-7). [ka] [In the formula, R α is the same as above.]

[0150] The structural unit (a4) 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 (a4), the amount of the structural unit (a4) relative to the total amount of all structural units constituting the component (A1) is preferably 1 to 30 mol %, and more preferably 3 to 20 mol %. By ensuring that the proportion of the structural unit (a4) is at least as large as the preferred lower limit, the effects of including the structural unit (a4) can be fully obtained, while by ensuring that the proportion is at most the preferred upper limit, it becomes easier to achieve a balance with other structural units.

[0151] In the resist composition of this embodiment, the component (A) preferably includes a polymeric compound (A1) that includes the structural unit (a1). Specific examples of the component (A1) include polymeric compounds comprising a repeating structure of the structural unit (a1) and the structural unit (a2), polymeric compounds comprising a repeating structure of the structural unit (a1) and the structural unit (a3), and polymeric compounds comprising a repeating structure of the structural unit (a1), the structural unit (a2), and the structural unit (a3).

[0152] The mass 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 about 1,000 to 50,000, more preferably about 10,000 to 30,000, and even more preferably about 18,000 to 22,000. When the Mw of component (A1) is equal to or less than the upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is equal to or greater than the lower limit of this range, the compound has excellent dry etching resistance and a good cross-sectional shape of the resist pattern. In particular, when the Mw of component (A1) is about 18,000 to 22,000, the compound acts to suppress acid diffusion.

[0153] The dispersity (Mw / Mn) of the component (A1) is not particularly limited, but is preferably about 1.0 to 4.0, more preferably about 1.0 to 3.0, and particularly preferably about 1.0 to 2.5, where Mn represents the number average molecular weight.

[0154] The component (A1) may be used alone or in combination of two or more types. The proportion of component (A1) within component (A), relative to the total mass of 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%. A proportion of 25 mass% or more facilitates the formation of a resist pattern that is excellent in various lithography properties, such as improved roughness and dimensional uniformity.

[0155] Manufacturing method of component (A1): Component (A1) can be produced by dissolving the monomers that derive each structural unit in a polymerization solvent, adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl 2,2'-azobisisobutyrate (e.g., V-601), and polymerizing the resulting solution. 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 are substituted with fluorine atoms, are effective in reducing development defects and LER (line edge roughness: unevenness on the line sidewalls).

[0156] In the resist composition of this embodiment, the component (A) may use either a single type of compound, or a combination of two or more types of compounds. The amount of the component (A) in the resist composition of this embodiment may be adjusted depending on factors such as the thickness of the resist film to be formed.

[0157] <Component (B): Acid Generator Component> In the resist composition of this embodiment, the acid generator component (B) is a component that generates an acid upon exposure, and includes an acid generator (B1) and an acid generator (B2) that is different from (B1).

[0158] ≪(B1) Component≫ The resist composition of this embodiment contains an acid generator (B1) (hereafter also referred to as "component (B1)") that has a group represented by the following formula (b1-1) in the anionic moiety.

[0159] [ka]

[0160] The component (B1) has a group represented by formula (b1-1) as the anion moiety, and the cation moiety is not particularly limited, and can have any cation moiety that has been proposed as a cation moiety for an acid generator for use in a chemically amplified resist composition. Such a cation moiety is ()(M m+ ) 1 / m Examples of the cations include those represented by the following formula: M m+ represents an m-valent organic cation. M m+ The organic cation in the formula (I) is preferably an onium cation, more preferably a sulfonium cation or an iodonium cation, and m is an integer of 1 or more. The preferred cation moiety (M m+ ) 1 / m Examples of the organic cations include those represented by the following general formulas (ca-1) to (ca-5).

[0161] [ka] [In the formula, R 201 ~R 207 , and R 211 ~R 212 each independently represents an aryl group, an alkyl group, or an alkenyl group which may have a substituent; R 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 may be bonded to each other to form a ring together with the sulfur atom in the formula. 208 ~R 209each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and 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, and L 201 represents -C(=O)- or -C(=O)-O-; Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group; x is 1 or 2; W 201 represents a (x+1)-valent linking group.

[0162] R 201 ~R 207 , and R 211 ~R 212 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 , and R 211 ~R 212 The alkyl group in the formula (I) is a chain or cyclic alkyl group, preferably having 1 to 30 carbon atoms. R 201 ~R 207 , and R 211 ~R 212 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms.

[0163] R 201 ~R 207 , and R 210 ~R 212 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 formulae (ca-r-1) to (ca-r-7):

[0164] [ka] [In the formula, R' 201are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0165] 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. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0166] R' 201 The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, the carbon number does not include the number of carbon atoms in the substituent.

[0167] R' 201 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the formula (I) include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings have been substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom.

[0168] R' 201Specific examples of the aromatic hydrocarbon group in the above include groups in which one hydrogen atom has been removed from the aromatic ring (aryl groups: for example, phenyl group, naphthyl group, etc.), and groups in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0169] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of the aliphatic hydrocarbon group containing a ring in its structure include an alicyclic hydrocarbon group (a group in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms.

[0170] 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. Among them, R' 201The 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.

[0171] 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 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-; alkyltrimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyltetramethylene 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.

[0172] Also, R' 201The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include the lactone-containing cyclic groups represented by the above general formulae (a2-r-1) to (a2-r-7), the —SO—-containing cyclic groups represented by the above general formulae (a5-r-1) to (a5-r-4), and other heterocyclic groups represented by the following general formulae (r-hr-1) to (r-hr-16).

[0173] [ka]

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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:

[0178] R' 201 In addition to those mentioned above, the optionally substituted cyclic group, the optionally substituted chain alkyl group, or the optionally substituted chain alkenyl group also includes the same as the acid-dissociable group represented by formula (a1-r-2) described above as the optionally substituted cyclic group or the optionally substituted chain alkyl group. 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 above general formulas (a2-r-1) to (a2-r-7), or an —SO2- containing cyclic group represented by each of the above general formulas (a5-r-1) to (a5-r-4) is preferred.

[0179] R 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they are not included in any heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or in any 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, in which case one ring in the formula containing the sulfur atom in its ring skeleton is a 3- to 10-membered ring, including 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 phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0180] 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. 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.

[0181] 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.

[0182] R 210 The alkyl group in the formula (I) is a chain or cyclic alkyl group, preferably having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 210 In the formula (a5-r-1), the -SO2-containing cyclic group which may have a substituent includes the same as the -SO2-containing cyclic groups represented by the above general formulas (a5-r-1) to (a5-r-4), respectively, and among these, "-SO2-containing polycyclic groups" are preferred, and the group represented by the general formula (a5-r-1) is more preferred.

[0183] In the above formulas (ca-4) and (ca-5), Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. Y 201 The arylene group in the formula (I) is the same as the above-mentioned R' 201 Examples of the aromatic hydrocarbon group in the above formula include groups in which one hydrogen atom has been removed from the aryl groups exemplified above. Y 201 The alkylene group and alkenylene group in the formula (I) are the same as those in the formula (I) above. 201 Examples of the chain alkyl group and chain alkenyl group include groups in which one hydrogen atom has been removed from the groups exemplified above as the chain alkyl group and chain alkenyl group.

[0184] In the above formulas (ca-4) and (ca-5), x is 1 or 2. W 201 is an (x+1)-valent, i.e., a divalent or trivalent linking group. W 201 The divalent linking group in the formula (a2-1) is preferably a divalent hydrocarbon group which may have a substituent. 21 Examples include divalent hydrocarbon groups which may have a substituent, such as those shown in the following. 201 The divalent linking group in may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferred.

[0185] W 201 The trivalent linking group in 201 Examples of the divalent linking group include a group in which one hydrogen atom has been removed from the divalent linking group shown in the formula (I), and a group in which the above divalent linking group is further bonded to the above divalent linking group. 201 The trivalent linking group in the formula (I) is preferably a group in which two carbonyl groups are bonded to an arylene group.

[0186] Specific examples of preferred cations represented by the above formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-129), respectively.

[0187] [ka]

[0188] [ka] [In the formula, g1, g2, and g3 represent the number of repeating units, 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.]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent, and the substituent is the same as R 201 ~R 207 , and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the group

[0194] [ka]

[0195] [ka]

[0196] Specific examples of preferred cations represented by the above formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0197] Specific examples of preferred cations represented by the above formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0198] [ka]

[0199] Specific examples of preferred cations represented by the above formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

[0200] [ka]

[0201] As the cation represented by the above formula (ca-5), cations represented by the following general formulas (ca-5-1) to (ca-5-3) are also preferred.

[0202] [ka]

[0203] Among the above, the cation part [(M m+ ) 1 / m is preferably a cation represented by general formula (ca-1), and more preferably a cation represented by formulas (ca-1-1) to (ca-1-129).

[0204] In the resist composition of this embodiment, the component (B1) may be used either as a single type, or in combination of two or more types. In the resist composition of this embodiment, the amount of the component (B1) relative to 100 parts by mass of the component (A) is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 2 to 5 parts by mass. When the amount of the component (B1) is at least as large as the lower limit of the above preferred range, lithography properties such as sensitivity, LWR performance, and defect resistance are further improved during resist pattern formation. On the other hand, when the amount is at most the upper limit of the preferred range, a homogeneous solution is more easily obtained when the components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition is further improved.

[0205] ≪(B2) Component≫ The resist composition of this embodiment also contains an acid generator component (hereafter referred to as “component (B2)”) other than the component (B1). The component (B2) is a compound different from the compound corresponding to the component (B1) described above, and does not have a group represented by formula (b1-1) in the anion moiety. There are no particular restrictions on the component (B2), and any of the compounds 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, iminosulfonate-based acid generators, and disulfone-based acid generators.

[0206] Examples of onium salt acid generators include compounds represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), compounds represented by general formula (b-2) (hereinafter also referred to as "component (b-2)"), and compounds represented by general formula (b-3) (hereinafter also referred to as "component (b-3)"). However, the compound represented by general formula (b-2) does not have a group represented by formula (b1-1) in the anion moiety.

[0207] [ka] [In the formula, R 101 , R 104 ~R 108R each independently represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. 104 , R 105 may be bonded to each other to form a ring. R 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 101 is a single bond or a divalent linking group containing an oxygen atom. 101 ~V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group. 101 ~L 102 are each independently a single bond or an oxygen atom. 103 ~L 105 are each independently a single bond, —CO— or —SO2—; m is an integer of 1 or more; M' m+ is an m-valent onium cation.

[0208] {anion part} Anion part of component (b-1) In formula (b-1), R 101 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. 101 The explanation for R' in the above formulas (ca-r-1) to (ca-r-7) is 201 This is the same as the explanation for the optionally substituted cyclic group, the optionally substituted chain alkyl group, or the optionally substituted chain alkenyl group in the above. Among them, R 101 is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, preferred are 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 above general formulas (a2-r-1) and (a2-r-3) to (a2-r-7); and an —SO2- containing cyclic group represented by each of the above general formulas (a5-r-1) to (a5-r-4).

[0209] In the above formula (b-1), Y 101 is a single bond or a divalent linking group containing an oxygen atom. Y 101 is a divalent linking group containing an oxygen atom, 101 may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms. Examples of such divalent linking groups containing an oxygen atom include linking groups represented by the following general formulae (y-al-1) to (y-al-8).

[0210] [ka] [In the formula, V' 101 is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' 102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.]

[0211] In the above formula, 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.

[0212] Y 101 As the linking group, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferred, and the linking groups represented by the above general formulae (y-al-1) to (y-al-6) are more preferred.

[0213] In the above formula (b-1), V 101 is a single bond, an alkylene group, or a fluorinated alkylene group. 101 The alkylene group and fluorinated alkylene group in the formula (V) preferably have 1 to 4 carbon atoms. 101 The fluorinated alkylene group in 101In particular, the alkylene groups V are substituted with fluorine atoms in part or all of the hydrogen atoms in the alkylene groups. 101 is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

[0214] In the above formula (b-1), R 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 102 is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

[0215] Specific examples of the anion moiety of the component (b-1) include, for example, Y 101 When Y is a single bond, examples of the anion include a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion or a perfluorobutanesulfonate anion; 101 When is a divalent linking group containing an oxygen atom, examples of the anions include those represented by any of the following formulae (an-1) to (an-3).

[0216] [ka] [In the formula, R” 101 R" represents an aliphatic cyclic group which may have a substituent, a group represented by any of the above formulae (r-hr-1) to (r-hr-6), or a chain alkyl group which may have a substituent; 102 R" is an aliphatic cyclic group which may have a substituent, a lactone-containing cyclic group represented by the above general formulas (a2-r-1), (a2-r-3) to (a2-r-7), or an -SO2- containing cyclic group represented by the above general formulas (a5-r-1) to (a5-r-4), respectively; 103 represents an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent; each v" is independently an integer of 0 to 3, each q" is independently an integer of 1 to 20, each t" is an integer of 1 to 3, and n" is 0 or 1.

[0217] R” 101 , R” 102 and R” 103 The optionally substituted aliphatic cyclic group represented by the formula R' 201 The substituents are preferably the groups exemplified as the cyclic aliphatic hydrocarbon groups in R'. 201 Examples of the substituents that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1) include the same as those that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1).

[0218] R” 103 The aromatic cyclic group which may have a substituent in the above R' 201 Preferably, the cyclic hydrocarbon group is one of the groups exemplified as the aromatic hydrocarbon group in the above.

[0219] The above-mentioned substituents include R' 201 Examples of the substituents that may substitute the aromatic hydrocarbon group in the above formula (1) include the same as those in the above formula (1).

[0220] R” 101 The optionally substituted chain alkyl group in R' 201 R" is preferably a group exemplified as a chain alkyl group in 103 The optionally substituted chain alkenyl group in R' 201 Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0221] Anion part of component (b-2) In formula (b-2), R 104 , R 105 are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is 201 However, R 104 , R 105 may be bonded to each other to form a ring. R 104 , R 105is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group.

[0222] The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and even more preferably 1 to 3 carbon atoms. 104 , R 105 The number of carbon atoms in the chain alkyl group of R is preferably as small as possible within the above range of carbon atoms, for reasons such as good solubility in resist solvents. 104 , R 105 In the chain alkyl group, the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength and the improved transparency to high-energy light of 200 nm or less and electron beams, which is preferable.

[0223] The proportion of fluorine atoms in the chain alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms have been substituted with fluorine atoms.

[0224] In formula (b-2), V 102 , V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and each represents V in formula (b-1). 101 The same can be mentioned.

[0225] In formula (b-2), L 101 , L 102 are each independently a single bond or an oxygen atom.

[0226] Anion part of component (b-3) In formula (b-3), R 106 ~R 108 are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is 201The same can be mentioned.

[0227] L 103 ~L 105 are each independently a single bond, —CO— or —SO2—.

[0228] {cation part} In formulas (b-1), (b-2) and (b-3), m is an integer of 1 or more, and M' m+ is an m-valent onium cation, and preferred examples thereof include a sulfonium cation and an iodonium cation, and examples thereof include the organic cations represented by the above general formulas (ca-1) to (ca-5).

[0229] Specific examples of preferred cations represented by the above formula (ca-1) include cations represented by the above formulas (ca-1-1) to (ca-1-129).

[0230] Specific examples of preferred cations represented by the above formula (ca-2) include diphenyliodonium cation and bis(4-tert-butylphenyl)iodonium cation.

[0231] Specific examples of preferred cations represented by the above formula (ca-3) include cations represented by the above formulas (ca-3-1) to (ca-3-6).

[0232] Specific examples of preferred cations represented by the above formula (ca-4) include cations represented by the above formulas (ca-4-1) to (ca-4-2).

[0233] Specific examples of preferred cations represented by the above formula (ca-5) include cations represented by the above formulas (ca-5-1) to (ca-5-3).

[0234] Among the above, the cation part [(M' m+ ) 1 / mis preferably a cation represented by general formula (ca-1), and more preferably a cation represented by formulas (ca-1-1) to (ca-1-129).

[0235] The component (B2) preferably has an anion moiety capable of generating a strong acid. The anion moiety capable of generating a strong acid is not particularly limited as long as it is an anion capable of generating a strong acid, and examples thereof include an anion capable of generating an acid whose acid dissociation constant (pKa) is preferably 0 or less, more preferably -1 or less, with no particular lower limit, but about -15.

[0236] In the resist composition of this embodiment, the component (B2) may be used either as a single type, or in combination of two or more types. Within the resist composition, the amount of the component (B2) relative to 100 parts by mass of the component (A) is preferably no more than 30 parts by mass, more preferably from 5 to 20 parts by mass, and even more preferably from 9 to 15 parts by mass. When the amount of component (B2) is at least as large as the lower limit of the above preferred range, lithography properties such as sensitivity, LWR performance, and defect resistance are further improved during resist pattern formation. On the other hand, when the amount is at most the upper limit of the preferred range, a homogeneous solution is more easily obtained when the components of the resist composition are dissolved in an organic solvent, and the storage stability of the resist composition is further improved.

[0237] <Component (D): Acid diffusion controller component> The resist composition of this embodiment contains, in addition to components (A) and (B), an acid diffusion controller component (D) (hereinafter also referred to as "component (D)"). Component (D) acts as a quencher (acid diffusion controller) that controls the diffusion of acid generated in the resist composition upon exposure (i.e., traps the acid).

[0238] The component (D) contains a photodegradable base (D0) (hereinafter also referred to as "component (D0)") having a group represented by the following formula (d0) in the anion moiety, and in the present invention, the component (D) does not contain a nitrogen-containing organic compound (D2) (hereinafter also referred to as "component (D2)").

[0239] [ka] [In the formula, Rb 1 represents a hydrocarbon group which may have a substituent, provided that Rb 1 does not contain halogen atoms.

[0240] Furthermore, the component (D) may further contain an acid diffusion controller (D') (hereinafter also referred to as "component (D')") other than the components (DO) and (D2).

[0241] ≪(D0) component≫ By using a resist composition that contains the component (D0), the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern. The component (D0) is not particularly limited as long as it has a group represented by the above formula (d0) in the anion moiety and is decomposed by exposure to light to lose its ability to control acid diffusion. The component (D0) does not function as a quencher in the exposed areas of the resist film because it decomposes and loses its acid diffusion control properties (basicity), but it does function as a quencher in the unexposed areas of the resist film.

[0242] Anion portion (group represented by general formula (d0)) The component (D0) has a group represented by formula (d0) in the anion moiety. In formula (d0), Rb 1 represents a hydrocarbon group which may have a substituent. The hydrocarbon group which may have a substituent is preferably a cyclic hydrocarbon 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 the above R' 201 The same can be mentioned.

[0243] Rb 1 is more preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic hydrocarbon group which may have a substituent. Rb 1 The chain alkyl group in may be either a straight chain or a branched chain.

[0244] 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.

[0245] 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.

[0246] Rb 1 The aliphatic cyclic hydrocarbon group in preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms. The aliphatic cyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic aliphatic cyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic aliphatic cyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0247] Among them, Rb 1 The aliphatic cyclic 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, and even 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, or the like, or a group in which one or more hydrogen atoms have been removed from camphor, or the like.

[0248] Rb 1 Examples of the substituent that the hydrocarbon group may have include a hydroxyl group, an oxo group, an alkyl group, an alkoxy group, an aryl group, a lactone-containing cyclic group represented by each of the above general formulae (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof, but halogen atoms are excluded.

[0249] The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

[0250] The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

[0251] In the aliphatic cyclic 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-.

[0252] 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).

[0253] Preferred examples of the group represented by general formula (d0) include groups represented by the following general formulae (d0-1) to (d0-23).

[0254] [ka]

[0255] The group represented by formula (d0) is preferably an anion capable of generating a weak acid. There are no particular limitations on the anion as long as it is capable of generating a weak acid, and examples thereof include an anion capable of generating an acid whose acid dissociation constant (pKa) is preferably greater than 0, more preferably 0.2 or greater, with no particular upper limit, but about 10.

[0256] Cation part There are no particular limitations on the cationic moiety of the component (D0), and it can have any cationic moiety that has been proposed as a cationic moiety in acid diffusion controllers for use in chemically amplified resist compositions. Such a cationic moiety is (M m+ ) 1 / m Examples of the cations include those represented by the following formula: M” m+ is an m-valent organic cation. M” m+ Preferred organic cations are the same as those represented by the above general formulas (ca-1) to (ca-5), with the cation represented by the above general formula (ca-1) being more preferred, and the cations represented by the above formulas (ca-1-1) to (ca-1-41), (ca-1-43) to (ca-1-103), (ca-1-105) to (ca-1-123), and (ca-1-125) to (ca-1-129) being even more preferred.

[0257] The component (D0) may be used singly, or in combination of two or more. The amount of the component (D0) in the resist composition relative to 100 parts by mass of the component (A) is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 5 to 10 parts by mass. When the content of the component (D0) is at least the lower limit of the preferred range, lithography properties such as sensitivity, LWR performance, and defect tolerance are improved. On the other hand, when the content is at most the upper limit, good sensitivity can be maintained and throughput is also excellent.

[0258] Manufacturing method of component (D0): There are no particular restrictions on the method for producing the component (D0), and it can be produced by known methods.

[0259] ≪(D2) component≫ In the resist composition of this embodiment, the acid diffusion controller component (D) does not include a nitrogen-containing organic compound (D2) (hereinafter also referred to as "component (D2)"). Examples of the component (D2) include aliphatic amines and aromatic amines. Aliphatic amines are amines that contain one or more aliphatic groups.

[0260] 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.

[0261] 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).

[0262] Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.

[0263] Specific examples of the aliphatic polycyclic amine 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.

[0264] 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.

[0265] Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole, or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, and N-tert-butoxycarbonylpyrrolidine.

[0266] When the component (D2) is contained as an acid diffusion controller, the sensitivity to the light source becomes too slow or the line width becomes rough.

[0267] ≪(D') component≫ In the resist composition of this embodiment, the acid diffusion controller component (D) can further include an acid diffusion controller (D') (hereinafter also referred to as "component (D')") other than components (DO) and (D2). There are no particular limitations on the component (D'), and any component known as an acid diffusion controller in conventional photoresist compositions can be appropriately selected and used. In the photoresist composition, component (D') acts as a quencher (acid diffusion controller) that traps acid generated by exposure. The component (D') may be a photodegradable base (D1) (hereinafter also referred to as "component (D1)") that decomposes upon exposure to light and loses its acid diffusion controllability.

[0268] Regarding component (D1) The component (D1) is not particularly limited as long as it does not fall under the category of components (D0) and (D2) and decomposes upon exposure to light to lose its acid diffusion controllability, and is preferably one or more compounds selected from the compounds represented by the following formula (d1-1) (hereinafter referred to as "component (d1-1)"): The component (d1-1) does not act as a quencher in the exposed areas of the photoresist film because it decomposes and loses its acid diffusion control properties (basicity), but acts as a quencher in the unexposed areas.

[0269] [ka] [In the formula, Rd 1 is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group; m is an integer of 1 or more; M" is an integer of 1 or more; m+ is an m-valent organic cation.

[0270] Anion part In formula (d1-1), Rd 1 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of these represents 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).

[0271] Preferred 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).

[0272] 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.

[0273] 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.

[0274] When the chain 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 and sulfur atoms.

[0275] 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).

[0276] Preferred examples of the anion moiety of the component (d1-1) are shown below.

[0277] [ka]

[0278] Cation part In formula (d1-1), M” m+ is an m-valent organic cation, and is the same as the cation moiety of the component (D0) above.

[0279] The component (d1-1) may be used alone or in combination of two or more. When the resist composition contains the component (D1), the amount of the component (D1) relative to 100 parts by weight of the component (S) is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, and even more preferably 1 to 6 parts by weight. 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.

[0280] Manufacturing method of component (D1): The method for producing the component (d1-1) is not particularly limited, and it can be produced by a known method.

[0281] <Other ingredients> In this embodiment, the resist composition may further contain other components in addition to the components (A), (B), and (D). Examples of other components include the components (E), (F), and (S) described below.

[0282] <Component (E): At least one compound selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof> The resist composition of this embodiment may contain, as an optional component, at least one compound (E) (hereinafter also referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxo acids, and derivatives thereof, for the purposes of preventing sensitivity degradation and improving the resist pattern shape and stability over time after exposure. Preferred organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Examples of derivatives of phosphorus oxoacids include esters in which the hydrogen atoms of the above oxoacids are substituted with hydrocarbon groups, and examples of the hydrocarbon groups include alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Examples of the derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphoric acid ester and diphenyl phosphoric acid ester. Examples of the derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Examples of the derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid.

[0283] In the resist composition of this embodiment, the component (E) may be used either as a single type, or in combination of two or more types. When the resist composition contains the component (E), the amount of the component (E) is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A).

[0284] <(F) Component: Fluorine additive component> The resist composition of this embodiment may contain a fluorine additive component (hereafter also referred to as “component (F)”) in order to impart water repellency to the resist film. Examples of the component (F) that can be used include the fluorine-containing polymer compounds described in JP 2010-002870 A, JP 2010-032994 A, JP 2010-277043 A, JP 2011-13569 A, and JP 2011-128226 A. More specific examples of the component (F) include polymers having a structural unit (f1) represented by the following formula (f1-1), excluding polymer compounds corresponding to the above-described component (A).

[0285] Preferred polymers having the structural unit (f1) include polymers (homopolymers) consisting solely of the structural unit (f1); copolymers of the structural unit (f1) and a structural unit represented by the following formula (m-1); and copolymers of the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and a structural unit represented by the following formula (m-1). Here, the structural unit represented by formula (m-1) 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.

[0286] [ka] [In the formula, R is the same as above. In formula (f1-1), Rf 102 and Rf 103 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Rf 102 and Rf 103 may be the same or different. 1 is an integer from 0 to 5, and Rf 101 is an organic group containing a fluorine atom. 21 is an alkyl group, and R 22 is the R 22 is a group that forms an aliphatic cyclic group together with the carbon atom to which it is attached.

[0287] In the above formula (f1-1), 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 an alkyl group having 1 to 5 carbon atoms is more preferred, an alkyl group having 1 to 5 carbon atoms is even more preferred, and a methyl group is particularly preferred.

[0288] 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 103 Examples of the alkyl group having 1 to 5 carbon atoms for R include the same alkyl groups having 1 to 5 carbon atoms as those for 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. 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.

[0289] In formula (f1-1), nf 1 is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 0 or 1.

[0290] 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 5 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.

[0291] In formula (m-1), R 21 The alkyl group in may be linear, branched, or cyclic, with linear or branched being preferred. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and even more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and the like. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, with a methyl group or an ethyl group being more preferred. The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, and the like, with an isopropyl group being particularly preferred.

[0292] In formula (m-1), R 22 is the R 22 R is a group that forms an aliphatic cyclic group together with the carbon atom to which it is attached. 22The aliphatic cyclic group formed by may be polycyclic or monocyclic. The monocyclic aliphatic cyclic group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably one having 3 to 10 carbon atoms, such as cyclopentane, cyclohexane, and cyclooctane. The polycyclic aliphatic cyclic group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, such as one having 7 to 12 carbon atoms, such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0293] The mass average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1000 to 60000, more preferably 10000 to 55000, and most preferably 20000 to 50000. When the Mw is equal to or less than the upper limit of this range, the resin has sufficient solubility in a resist solvent for use as a resist, while when the Mw is equal to or greater than the lower limit of this range, the resin exhibits good dry etching resistance and the cross-sectional shape of the resist pattern.

[0294] 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 1.2 to 2.5.

[0295] The component (F) may be used alone 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).

[0296] <Component (S): Organic solvent component> The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter also referred to as “component (S)”). The component (S) can be any solvent that is capable of dissolving the individual components used and forming a homogeneous solution, and any solvent that is appropriately selected from those that are known to be used as solvents for chemically amplified resist compositions can be used.

[0297] Examples of the (S) component include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; and compounds having an ether bond such as monoalkyl ethers, monomethyl ethers, monoethyl ethers, monopropyl ethers, and monobutyl ethers of the above polyhydric alcohols or compounds having an ester bond, or monophenyl ethers. Examples of suitable organic solvents include derivatives of hydric alcohols (among which, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred); cyclic ethers such as dioxane, and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene, and dimethyl sulfoxide (DMSO).

[0298] In the resist composition of this embodiment, the component (S) may be used either as a single solvent, or as a mixed solvent of two or more different solvents. Among these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred. A mixed solvent of PGMEA and a polar solvent is also preferred. The blending ratio (mass ratio) may be appropriately determined taking into consideration the compatibility between PGMEA and the polar solvent, and is preferably within the range of 1:9 to 9:1, and more preferably 2:8 to 8:2. More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA:EL or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3. A mixed solvent of PGMEA, PGME, and cyclohexanone is also preferred. Another preferred component (S) is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone, in which the mass ratio of the former to the latter is preferably 70:30 to 95:5.

[0299] 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, component (S) is used so that the solids concentration of the resist composition falls within the range of 1 to 20 mass %, and preferably 2 to 15 mass %.

[0300] The resist composition 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, etc.

[0301] The resist composition of the present embodiment has excellent lithography properties such as sensitivity, LWR performance, CDU performance, EL performance, defect resistance, and suppression of film shrinkage after PEB, and in particular, has a good balance of sensitivity, LWR performance, and defect resistance.

[0302] (Method for forming a resist pattern) The method for forming a resist pattern of the present embodiment includes the steps of forming a resist film on a support using the resist composition of the above-described embodiment, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

[0303] One embodiment of the resist pattern forming method is, for example, a resist pattern forming method carried out as follows. First, the resist composition of the above-described embodiment is applied onto a substrate using a spinner or the like, and then baked (post-apply bake (PAB)) at a temperature of 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 EUV exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without 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. In the case of an alkali development process, the development is performed using an alkali developer, and in the case of a solvent development process, the development is performed using a developer containing an organic solvent (organic developer). The method of forming a resist pattern according to this embodiment is particularly useful in the case of a solvent development process. 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, after the above-mentioned development treatment or rinsing treatment, a treatment may be carried out in which the developer or rinsing liquid adhering to the pattern is removed 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 carried out after the development treatment. In this manner, a resist pattern can be formed.

[0304] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those provided with a predetermined wiring pattern. 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, for example, copper, aluminum, nickel, and gold.

[0305] The support may also be a substrate as described above on which an inorganic and / or organic film is provided. Examples of inorganic films include inorganic anti-reflective coatings (inorganic BARCs). Examples of organic films include organic anti-reflective coatings (organic BARCs) and organic films such as lower organic films in multilayer resist methods. Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the lower organic film is patterned using the resist pattern formed on the upper resist film as a mask, and it is said to be able to form patterns with a high aspect ratio. In other words, with the multilayer resist method, the required thickness can be ensured by the lower organic film, so the resist film can be made thinner and fine patterns with a high aspect ratio can be formed. Multilayer resist methods are basically divided into a two-layer structure consisting of an upper resist film and a lower organic film (two-layer resist method), and a three-layer structure consisting of three or more layers with one or more intermediate layers (such as a metal thin film) between the upper resist film and the lower organic film (three-layer resist method).

[0306] The wavelength used for exposure is not particularly limited, and radiation such as an ArF excimer laser, a KrF excimer laser, an F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, soft X-rays, etc. The resist composition is highly useful for KrF excimer lasers, ArF excimer lasers, EB, or EUV, and even more useful for ArF excimer lasers, EB, or EUV.

[0307] 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. The refractive index of such a solvent is not particularly limited as long as it is within the above range. Examples of solvents having a refractive index greater than that of air and smaller than that of the resist film include water, fluorine-based inert liquids, silicon-based solvents, and hydrocarbon-based solvents. Specific examples of fluorine-based inert liquids include liquids containing fluorine-based compounds such as C3HCl2F5, C4F9OCH3, C4F9OC2H5, and C5H3F7 as main components, and preferably have a boiling point of 70 to 180° C., more preferably 80 to 160° C. Fluorine-based inert liquids having a boiling point within the above range are preferred because the medium used for immersion can be easily removed after exposure is complete. As the fluorine-based inert liquid, particularly preferred are perfluoroalkyl compounds in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms, specifically perfluoroalkyl ether compounds and perfluoroalkylamine compounds. More specifically, the perfluoroalkyl ether compound may be perfluoro(2-butyl-tetrahydrofuran) (boiling point: 102°C), and the perfluoroalkylamine compound may be perfluorotributylamine (boiling point: 174°C). As the liquid immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility, and the like.

[0308] 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 that can dissolve component (A) (component (A) before exposure), and can be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents. Ketone-based solvents are organic solvents that contain CC(=O)-C in their structure. Ester-based solvents are organic solvents that contain CC(=O)-OC in their structure. Alcohol-based solvents are organic solvents that contain an alcoholic hydroxyl group in their structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile-based solvents are organic solvents that contain a nitrile group in their structure. Amide-based solvents are organic solvents that contain an amide group in their structure. Ether-based solvents are organic solvents that contain COC in their structure. Some organic solvents contain multiple types of functional groups that characterize the above-mentioned solvents in their structure, and in such cases, the term "organic solvent" refers to any solvent type containing the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether is considered to be both an alcohol-based solvent and an ether-based solvent in the above classification.

[0309] The hydrocarbon solvent is a hydrocarbon solvent that is composed of a hydrocarbon that may be halogenated and has no substituents other than halogen atoms. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, and fluorine atoms are preferred.

[0310] Of the above, the organic solvent contained in the organic developer is preferably a polar solvent, and more preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

[0311] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), etc. Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

[0312] Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether ...propyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Lithium monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate Examples of the alkyl esters include butyl, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate.Among these, butyl acetate is preferred as the ester solvent.

[0313] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0314] 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. The surfactant is preferably a nonionic surfactant, and more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant. When a surfactant is added, the amount added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the organic developer.

[0315] 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 that is rotating at a constant speed (dynamic dispense method).

[0316] The organic solvent contained in the rinse solution used in the rinsing treatment after the development treatment in the solvent development process can be, for example, an organic solvent that does not easily dissolve the resist pattern, selected from the organic solvents listed above as organic solvents used in the organic developer. Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. Among these, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, and amide solvents is preferred, at least one solvent selected from alcohol solvents and ester solvents is more preferred, and alcohol solvents are particularly preferred.

[0317] The alcohol-based solvent used in the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched, or cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred.

[0318] These organic solvents may be used alone or in combination of two or more. They may also be used in combination with other organic solvents or water. However, taking into consideration the development characteristics, the amount of water in the rinse solution is preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the rinse solution.

[0319] The rinse solution may contain known additives as needed. Examples of such additives include surfactants. Examples of surfactants include those described above, and nonionic surfactants are preferred, with nonionic fluorine-based surfactants and nonionic silicon-based surfactants being more preferred. When a surfactant is added, the amount added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse liquid.

[0320] 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). [Example]

[0321] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0322] <Preparation of Photoresist Composition> The photoresist compositions of the examples were prepared by mixing and dissolving the components shown in the table below.

[0323] [Table 1]

[0324] In the above table, the abbreviations have the following meanings: The numbers in brackets [ ] are the blend amounts (parts by mass).

[0325] [Component (A)] A-1: Resin represented by the following formula (A-1) (molar ratio of each structural unit x / y / z=50 / 40 / 10, mass average molecular weight: 20,000) A-2: Resin represented by the following formula (A-1) (molar ratio of each structural unit x / y / z=50 / 40 / 10, mass average molecular weight: 10,000)

[0326] [ka]

[0327] [(B) Component] B-1 to B-4: Acid generators represented by the following formulas (B-1) to (B-4), respectively

[0328] [ka]

[0329] [(D) component] D-1 to D-4: Acid diffusion controllers represented by the following formulas (D-1) to (D-4), respectively

[0330] [ka]

[0331] [(E) component] E-1: An additive represented by the following formula (E-1):

[0332] [ka]

[0333] [Component (F)] F-1: Fluorine additive represented by the following formula (F-1) (molar ratio of each structural unit x / y=80 / 20, mass average molecular weight: 45,000)

[0334] [ka]

[0335] [(S) component] S-1: Propylene glycol monomethyl ether acetate S-2: Propylene glycol monomethyl ether

[0336] <Formation of resist pattern> An organic anti-reflective coating composition "ARC95" (manufactured by Brewer Science) was applied to a 12-inch (300 mm) silicon wafer using a spinner, and then baked on a hot plate at 205°C for 60 seconds to dry, forming an organic anti-reflective coating with a thickness of 90 nm. The resist was applied onto the anti-reflective coating using a spinner, pre-baked (PAB) on a hot plate at 110° C. for 60 seconds, and dried to form a resist film with a thickness of 90 nm. Using an ArF immersion exposure system NSR-S610C [Nikon Corporation; NA (numerical aperture) = 1.30, Dipole (in / out = 0.78 / 0.98) with Polano, immersion medium: water], the sample was selectively irradiated with an ArF excimer laser (193 nm) through a photomask (6% halftone). This was followed by a post-exposure bake (PEB) treatment at 90°C for 60 seconds. This was followed by alkaline development at 23°C using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) (trade name: NMD-3, Tokyo Ohka Kogyo Co., Ltd.) for 10 seconds. This was followed by a 30-second rinse with purified water and subsequent drying. As a result, a line-and-space pattern (hereinafter referred to as an LS pattern) with a line width of 38 nm and a pitch of 81 nm was formed in each example. The sensitivity when the above 38 nm LS pattern is formed is the optimum exposure dose Eop (mJ / cm 2 The Eop of each resist composition is shown in Table 2.

[0337] <Defect evaluation> The LS patterns obtained in the lithography evaluation were observed using a surface defect observation device KLA2905 (product name) manufactured by KLA-Tencor Corp. The number of development defects in the unexposed areas per silicon wafer (300 mm) was measured and evaluated according to the following evaluation criteria. ○: The number of development defects is 1500 or less ×: The number of development defects is 1501 or more

[0338] <Line width roughness (LWR) evaluation> The optimum exposure dose Eop (mJ / cm) for forming the LS pattern 2 For an LS pattern with a line width of 38 nm and a pitch of 81 nm formed on a substrate, the line width was measured at 400 locations along the line length using a critical dimension SEM (scanning electron microscope, product name: CG-5000, manufactured by Hitachi High-Technologies). From the results, three times the standard deviation (s) (3s) was calculated as a measure of LWR. The smaller the 3s value, the less rough the line width, meaning that an LS pattern with a more uniform width was obtained. The results are shown in Table 2.

[0339] [Table 2]

[0340] As shown by the above results, the resist patterns formed using the resist compositions of Examples 1 to 5 employing the present invention were excellent in all of sensitivity, LWR performance, and defect resistance. On the other hand, the composition of Comparative Example 1, which did not contain the component (B1), and the composition of Comparative Example 4, which did not contain the photodegradable base (D0) as the component (D) but contained the nitrogen-containing organic compound (D2), exhibited poor LWR performance. The compositions of Comparative Examples 2 and 6, which did not contain the component (B2), and the composition of Comparative Example 3, which did not contain the photodegradable base (D0), exhibited poor LWR performance and defect resistance. The composition of Comparative Example 5, which did not contain the component (B2) but contained the nitrogen-containing organic compound (D2) as the component (D), and the composition of Comparative Example 6, which did not contain the component (B2), exhibited poor sensitivity and defect resistance.

[0341] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but is defined by the appended claims.

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, a base component (A) whose solubility in a developer changes under the action of an acid; an acid generator component (B) that generates acid upon exposure to light, and an acid diffusion controller (D) that controls the diffusion of the acid generated from the acid generator component (B) upon exposure, the acid generator component (B) includes an acid generator (B1) having a group represented by the following formula (b1-1) at the anion moiety, and an acid generator (B2) different from (B1): a resist composition, wherein the acid diffusion controller (D) comprises a photodegradable base (D0) having a group represented by the following formula (d0) in the anion moiety, and does not comprise a nitrogen-containing organic compound (D2) (however, this does not include resist compositions that contain a copolymer consisting of a structural unit derived from a compound represented by the following formula (a6-1), a structural unit derived from a compound represented by the following formula (a6-2), and a structural unit derived from a compound represented by the following formula (a6-3), the following compound (B-5), the following compound (B-6), the following compound (D-5), the following compound (F-2), and a ZX solvent (a mixed solvent containing propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether in a mass ratio of 7:3)). 【Chemical 1】 [In the formula, Rb １ represents a hydrocarbon group which may have a substituent, provided that Rb １ does not contain halogen atoms. 【Chemistry 2】 【Chemistry 3】 [In the formula, the copolymerization composition ratio is l f / m f = 50 / 50.]

2. The resist composition according to claim 1, wherein the acid generator (B2) is selected from the group consisting of a compound represented by the following formula (b-1), a compound represented by the following formula (b-2), and a compound represented by the following formula (b-3), with the proviso that the compound represented by formula (b-2) does not have a group represented by formula (b1-1) in its anion moiety. 【Chemistry 4】 [In the formula, R １０１ , R １０４ ~R １０８ R are each independently a halogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. １０４ , R １０５ may be bonded to each other to form a ring. １０２ is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. １０１ is a single bond or a divalent linking group containing an oxygen atom. １０１ ~V １０３ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. １０１ ~L １０２ are each independently a single bond or an oxygen atom. １０３ ~L １０５ each independently represents a single bond, —CO— or —SO ２ m is an integer of 1 or more, and M' ｍ＋ is an m-valent onium cation.

3. 3. The resist composition according to claim 1, wherein the group represented by formula (d0) is selected from groups represented by the following formulas (d0-1) to (d0-23): 【Chemistry 5】

4. 4. The resist composition according to claim 1, further comprising an additive (E).

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

6. 6. A method for forming a resist pattern, comprising: forming a resist film on a support using the resist composition according to claim 1; exposing the resist film to light; and developing the exposed resist film using a developer.

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