Resist material and pattern formation method

Abstract

To provide a resist material having high sensitivity and improved LWR (line width roughness) and CDU (critical dimension uniformity) for both positive and negative resist types, and a patterning process using the resist material.SOLUTION: A resist material includes, as a quencher, a sulfonium salt of a substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid, and / or a sulfonium salt of a substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. This is because the proliferation of 5G high-speed communication and artificial intelligence (AI) necessitates high-performance devices to process them. As a cutting-edge miniaturization technology, mass production of 5nm node devices is underway using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm. Furthermore, research using EUV lithography is progressing for next-generation 3nm node and the following-generation 2nm node devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion is becoming a problem. To ensure resolution in fine patterns with dimensions of 45 nm or larger, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast as has been conventionally proposed (Non-Patent Literature 1). However, since chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempting to suppress acid diffusion to the extreme by lowering the post-exposure bake (PEB) temperature or shortening the time results in a significant decrease in sensitivity and contrast.

[0004] The relationship between sensitivity, resolution, and edge roughness is shown as a triangle trade-off. To improve resolution, it is necessary to suppress acid diffusion, but as the acid diffusion distance decreases, sensitivity decreases.

[0005] Adding an acid generator that produces bulky acids is effective in suppressing acid diffusion. Therefore, it has been proposed to include repeating units derived from onium salts having polymerizable unsaturated bonds in the polymer. In this case, the polymer also functions as an acid generator (polymer-bound type acid generator). Patent Document 1 proposes sulfonium salts and iodonium salts having polymerizable unsaturated bonds that generate specific sulfonic acids. Patent Document 2 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0006] Acid-unstable groups used in (meth)acrylate polymers for ArF resist materials undergo deprotection reactions by using a photoacid generator that produces sulfonic acid with a fluorine atom substituted at the α-position. However, deprotection reactions do not proceed with acid generators that produce sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position. When a sulfonium salt or iodonium salt that produces sulfonic acid with a fluorine atom substituted at the α-position is mixed with a sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position, the sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position undergoes ion exchange with the sulfonic acid with a fluorine atom substituted at the α-position. Since the sulfonic acid with a fluorine atom substituted at the α-position generated by light reverts back to the sulfonium salt or iodonium salt through ion exchange, the sulfonium salt or iodonium salt of sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position functions as a quencher. A resist material has been proposed that uses a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher (Patent Document 3).

[0007] Sulfonium salt type quenchers that generate various carboxylic acids have been proposed. In particular, sulfonium salts of salicylic acid and β-hydroxycarboxylic acid (Patent Document 4), salicylic acid derivatives (Patent Documents 5 and 6), fluorosalicylic acid (Patent Document 7), and hydroxynaphthoic acid (Patent Document 8) have been shown. Salicylic acid, in particular, has the effect of suppressing acid diffusion through intramolecular hydrogen bonding between the carboxylic acid and the hydroxyl group.

[0008] On the other hand, it has been pointed out that quencher aggregation reduces the dimensional uniformity of the resist pattern. By preventing quencher aggregation in the resist film and homogenizing its distribution, it is expected that the dimensional uniformity of the pattern after development will be improved.

[0009] The trifluoromethoxy group is called a superhalogen due to its strong electron-withdrawing effect and is used in pharmaceuticals, agrochemicals, and liquid crystal materials. 4-trifluoromethoxybenzoic acid has been shown as an anion for sulfonium salts used in resists (Patent Document 9). [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2006-045311 [Patent Document 2] Japanese Patent Publication No. 2006-178317 [Patent Document 3] Japanese Patent Publication No. 2007-114431 [Patent Document 4] WO2018 / 159560 [Patent Document 5] Japanese Patent Publication No. 2020-203984 [Patent Document 6] Japanese Patent Publication No. 2020-91404 [Patent Document 7] WO2010 / 095698 [Patent Document 8] Japanese Patent Publication No. 2019-120760 [Patent Document 9] Japanese Patent Publication No. 2007-284405 [Non-patent literature]

[0011] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Overview of the project] [Problems that the invention aims to solve]

[0012] This invention has been made in view of the above circumstances, and aims to provide a resist material that is highly sensitive, has improved LWR (line width roughness) and CDU (dimensional uniformity), whether it is a positive or negative type, and a pattern formation method using the same. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides: As a quencher, The present invention provides a resist material comprising a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethoxy)benzoic acid, and / or a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethylthio)benzoic acid.

[0014] Such materials, whether positive or negative, are highly sensitive and exhibit improved LWR and CDU.

[0015] It is preferable that the sulfonium salt of the substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid, and / or the sulfonium salt of the substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid, is represented by the following general formula (1). [ka] (In the formula, R 1 is a hydrogen atom, or a group selected from linear, branched, or cyclic alkyl, alkoxy, alkoxycarbonyl, or acyl groups having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an alkynyl group having 2 to 15 carbon atoms. The group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may be an acid-unstable group. X is an oxygen atom or a sulfur atom. m and n are 1 or 2, respectively. R 2 ~R 4Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 2 and R 3 However, they may bond to each other, forming a ring with the sulfur atom to which they are bonded.

[0016] Such a material can be used to create a resist that is more reliably sensitive and has improved LWR and CDU.

[0017] Furthermore, in this invention, As a quencher, The present invention provides a resist material comprising one or more of the following: a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethoxybenzoic acid, and a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid.

[0018] Such materials, whether positive or negative, are highly sensitive and exhibit improved LWR and CDU.

[0019] It is preferable that one or more of the above-mentioned substituted or unsubstituted sulfonium salts of hydroxy(difluoromethoxy)benzoic acid, substituted or unsubstituted sulfonium salts of hydroxy(difluoromethylthio)benzoic acid, sulfonium salts of 2- or 3-di or trifluoromethoxybenzoic acid, and sulfonium salts of 2- or 3-di or trifluoromethylthiobenzoic acid are represented by the following general formula (1'). [ka] (In the formula, R 1´is a group selected from a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted amino group, or a linear, branched or cyclic alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, alkenyloxy group having 2 to 15 carbon atoms, or alkynyloxy group having 2 to 15 carbon atoms, and the group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxy group, and may be an acid-labile group, but R 1´ When is a hydrogen atom, F q H p The substitution position of the C-X- group is the 2-position or 3-position. p is 0 or 1, q is 2 or 3. X is an oxygen atom or a sulfur atom. m and n are each 1 or 2. R 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms which may contain a hetero atom. Further, R 2 and R 3 may combine with each other to form a ring together with the sulfur atom to which they are attached.)

[0020] If it is such a thing, it is more surely highly sensitive, and it can be made into a resist material with improved LWR and CDU.

[0021] Furthermore, it is preferably one containing an acid generator that generates an acid.

[0022] If it is such a thing, the said sulfonium salt functions as a quencher, and the resist material of this invention functions.

[0023] It is preferable that the acid generator generates a sulfonic acid, an imidic acid or a methidic acid.

[0024] If it is such a thing, it is more suitable as an acid generator.

[0025] Furthermore, it is preferably one containing an organic solvent.

[0026] With such a material, each component can be dissolved and used suitably as a resist material.

[0027] Furthermore, it is preferable that the base polymer is included.

[0028] Such a material would be suitable as a resist material.

[0029] It is preferable that the base polymer contains repeating units represented by the following general formula (a1) and / or repeating units represented by the following general formula (a2). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 These are single bonds or ester bonds. 3 These are single bonds, ether bonds, or ester bonds. 11 and R 12 These are, independently, acid-unstable groups. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of which may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

[0030] Such a material, containing acid-unstable groups, is suitable as a positive-type resist material.

[0031] Preferably, the resist material is a chemically amplified positive-type resist material.

[0032] The resist material of the present invention can function as a chemically amplified positive resist material.

[0033] It is also preferable that the base polymer does not contain acid-unstable groups.

[0034] Such a material, free from acid-unstable groups, is suitable as a negative-type resist material.

[0035] Preferably, the resist material is a chemically amplified negative resist material.

[0036] The resist material of the present invention can function as a chemically amplified negative resist material.

[0037] Preferably, the base polymer further contains at least one repeating unit selected from the following general formulas (f1) to (f3). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to single bonds, aliphatic hydrocarbylene groups with 1 to 6 carbon atoms, phenylene groups, naphthylene groups, ester bonds, or groups with 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11 This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 These are single bonds or ester bonds. 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- Z 31This is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. 4 This is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, phenylene groups substituted with trifluoromethyl groups, -OZ 51 -, -C(=O)-OZ 51 -or -C(=O)-NH-Z 51 - is Z 51 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 15 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may also be a combination thereof, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom and / or a hydroxyl group. 21 ~R 28 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 23 and R 24 or R 26 and R 27 These may be bonded to each other, forming a ring with the sulfur atom to which they are bonded. - (It is a non-nucleophilic counterion.)

[0038] Such a substance would function as an acid generator within the base polymer.

[0039] Furthermore, it is preferable that the product contains a surfactant.

[0040] With this type of material, it is possible to improve or control the coating properties of the resist material.

[0041] Furthermore, the present invention provides a pattern formation method characterized by comprising the steps of forming a resist film on a substrate using the above-mentioned resist material, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[0042] This pattern formation method allows for the creation of good patterns.

[0043] It is preferable to use KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet light with a wavelength of 3 to 15 nm as the high-energy beam.

[0044] Using such high-energy rays allows for the formation of better patterns. [Effects of the Invention]

[0045] The sulfonium salts of the above-mentioned substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid, and / or the sulfonium salts of the above-mentioned substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid, are quenchers that suppress acid diffusion. This results in low acid diffusion properties, making it possible to improve LWR and CDU. As a result, it is possible to construct highly sensitive resist materials with low LWR and improved CDU. [Modes for carrying out the invention]

[0046] In resist materials, there is a need for the development of a quencher that can improve the LWR of line patterns and the dimensional uniformity (CDU) of hole patterns, while also improving sensitivity. To achieve this, it is necessary to further reduce image blurring due to diffusion.

[0047] The inventors, after diligent research to achieve the above objectives, have discovered that a resist material to which a substituted or unsubstituted sulfonium salt of hydroxy(di or trifluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(di or trifluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethoxybenzoic acid, or a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid is added acts as a quencher to suppress acid diffusion. The excellent acid diffusion suppression effect due to the presence of substituted or unsubstituted hydroxyl and carboxyl groups within the anion molecule, the improved dissolution contrast when the hydroxyl group is substituted with an acid-unstable group, and the high electron-withdrawing effect due to the presence of trifluoromethoxy or trifluoromethylthio groups, as well as the effect of preventing aggregation of the quencher due to electron repulsion of bulky groups, improve LWR and CDU, resulting in a resist material with excellent resolution and a wide process margin. Thus, the inventors have completed the present invention.

[0048] In other words, the present invention is As a quencher, The resist material comprises a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethoxy)benzoic acid, and / or a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethylthio)benzoic acid.

[0049] Furthermore, the present invention, As a quencher, The resist material comprises one or more of the following: a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethoxybenzoic acid, and a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid.

[0050] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0051] [Resist material] The resist material of the present invention contains, as a quencher, one or more of the following: a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethoxy)benzoic acid, and / or a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethylthio)benzoic acid, or a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid, and a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid.

[0052] [Sulfonium salts of substituted or unsubstituted hydroxy(di or trifluoromethoxy)benzoic acid, sulfonium salts of substituted or unsubstituted hydroxy(di or trifluoromethylthio)benzoic acid, sulfonium salts of 2- or 3-di or trifluoromethoxybenzoic acid, sulfonium salts of 2- or 3-di or trifluoromethylthiobenzoic acid] Preferably, one or more of the above-mentioned substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid sulfonium salts, and / or substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid sulfonium salts, substituted or unsubstituted hydroxy(difluoromethoxy)benzoic acid sulfonium salts, substituted or unsubstituted hydroxy(difluoromethylthio)benzoic acid sulfonium salts, 2- or 3-di or trifluoromethoxybenzoic acid sulfonium salts, and 2- or 3-di or trifluoromethylthiobenzoic acid sulfonium salts (hereinafter also referred to as sulfonium salt A) are represented by the following general formula (1) and the following general formula (1'). [ka]

[0053] In the above general formula (1), R 1is a hydrogen atom, or a group selected from linear, branched, or cyclic alkyl, alkoxy, alkoxycarbonyl, or acyl groups having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an alkynyl group having 2 to 15 carbon atoms. The group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may be an acid-unstable group. X is an oxygen atom or a sulfur atom. m and n are 1 or 2, respectively. R 2 ~R 4 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 2 and R 3 However, they may bond to each other, forming a ring with the sulfur atom to which they are bonded.

[0054] In the above general formula (1'), R 1´ The group is selected from a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted amino group, or a linear, branched, or cyclic alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, alkenyloxy group, or alkynyloxy group having 1 to 15 carbon atoms, and the group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may be an acid-unstable group, but R 1´ If it is a hydrogen atom, then F q H p The substitution position of the CX- group is at position 2 or 3. p is 0 or 1, q is 2 or 3. X is an oxygen atom or a sulfur atom. m and n are each 1 or 2. R 2 ~R 4 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 2 and R 3 However, they may bond to each other, forming a ring with the sulfur atom to which they are bonded.

[0055] The anions of the sulfonium salt represented by the above general formula (1) include, but are not limited to, those listed below.

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] Examples of anions of sulfonium salts represented by the above general formula (1') include, but are not limited to, those shown as specific examples of anions of sulfonium salts represented by the above general formula (1), and those shown below.

[0065] [ka]

[0066] In the above general formulas (1) and (1'), R 2 ~R 4 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, preferably 1 to 20 carbon atoms, which may contain a halogen atom or a heteroatom.

[0067] R 2 ~R 4 Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine atoms.

[0068] R 2 ~R 4The hydrocarbyl group, represented by , having 1 to 25 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C25 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; C3-C25 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; C2-C25 alkenyl groups such as vinyl, propenyl, butenyl, and hexenyl; and ethynyl groups. Examples include alkynyl groups with 2 to 25 carbon atoms, such as propynyl and butynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 25 carbon atoms, such as cyclohexenyl and norbornenyl groups; aryl groups with 6 to 25 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl groups; aralkyl groups with 7 to 25 carbon atoms, such as benzyl and phenethyl groups; and groups obtained by combining these.

[0069] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a mercapto group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0070] Also, R 2 and R 3 However, they may bond to each other and form a ring with the sulfur atom to which they are bonded. In this case, the ring has a structure as shown below. [ka] (In the formula, the dashed line represents R 4 (This is a combination of the two.)

[0071] The cations of the sulfonium salts represented by the above general formulas (1) and (1') include, but are not limited to, those listed below. [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075]

change

[0076]

change

[0077]

change

[0078]

change

[0079]

change

[0080]

change

[0081]

change

[0082]

change

[0083]

change

[0084]

change

[0085]

change

[0086]

change

[0087]

change

[0088]

change

[0089]

change

[0090]

change

[0091]

change

[0092]

change

[0093]

change

[0094]

change

[0095] Sulfonium salt A can be synthesized, for example, by ion exchange of a hydrochloride or carbonate containing a sulfonium cation with substituted or unsubstituted hydroxytrifluoromethoxybenzoic acid or substituted or unsubstituted hydroxytrifluoromethylthiobenzoic acid.

[0096] In the resist material of the present invention, the content of sulfonium salt A is preferably 0.001 to 50 parts by mass, and more preferably 0.01 to 40 parts by mass, per 100 parts by mass of the base polymer described later. Sulfonium salt A may be used alone or in combination of two or more types.

[0097] [Base polymer] The resist material of the present invention may contain a base polymer. In the case of a positive-type resist material, the base polymer contains repeating units containing acid-unstable groups. The repeating units containing acid-unstable groups are preferably the repeating units represented by the following general formula (a1) (hereinafter also referred to as repeating unit a1) and / or the repeating units represented by the following general formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0098] In the above general formulas (a1) and (a2), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 These are single bonds or ester bonds. 3 These are single bonds, ether bonds, or ester bonds. 11 and R 12 These are, independently, acid-unstable groups. Furthermore, if the above base polymer contains both repeating unit a1 and repeating unit a2, R 11 and R 12 These may be identical or different from one another. 13R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of which may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

[0099] Examples of monomers that give repeating unit a1 are listed below, but are not limited to these. Note that in the following formula, R A and R 11 This is the same as above. [ka]

[0100] Examples of monomers that give repeating units a2 are listed below, but are not limited to these. Note that in the following formula, R A and R 12 This is the same as above. [ka]

[0101] R in the above general formulas (1), (1'), (a1), and (a2) 1 , R 1´ , R 11 and R 12 Examples of acid-unstable groups represented by include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0102] Typically, the above-mentioned acid-unstable groups include those represented by the following general formulas (AL-1) to (AL-3). [ka] (In the equation, dashed lines represent connections.)

[0103] In the above general formulas (AL-1) and (AL-2), R L1and R L2 is each independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferable, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferable.

[0104] In the general formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0105] In the general formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferable. Further, any two of R L2 , R L3 and R L4 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded or a carbon atom and an oxygen atom. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0106] In the general formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferable. Further, R L5 , R L6 and R L7Any two of these may bond with each other to form a ring with 3 to 20 carbon atoms. A ring with 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0107] When the base polymer of the above-mentioned resist material contains repeating units a1 and a2, it is a chemically amplified positive-type resist material.

[0108] It is also preferable that the base polymer of the above-mentioned resist material does not contain acid-unstable groups, in which case the resist material is a chemically amplified negative-type resist material.

[0109] The above base polymer may contain repeating unit b which includes a phenolic hydroxyl group as an adhesion group. Examples of monomers that give repeating unit b are listed below, but are not limited to these. Note that in the following formula, R A This is the same as above. [ka]

[0110] [ka]

[0111] [ka]

[0112] The above base polymer may also contain repeating units c as other adhesive groups, including hydroxyl groups other than phenolic hydroxyl groups, lactone rings, sultone rings, ether bonds, ester bonds, sulfonic acid ester bonds, carbonyl groups, sulfonyl groups, cyano groups and / or carboxyl groups. Examples of monomers that give repeating units c are listed below, but are not limited to these. In the following formula, R A This is the same as above. [ka]

[0113]

Chem.

[0114]

Chem.

[0115]

Chem.

[0116]

Chem.

[0117]

Chem.

[0118]

Chem.

[0119]

Chem.

[0120]

Chem.

[0121] The above base polymer may contain a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. Examples of the monomer that gives the repeating unit d include, but are not limited to, the following.

Chem.

[0122] The above base polymer may contain repeating units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindan, vinylpyridine, or vinylcarbazole.

[0123] The above base polymer may contain repeating units f derived from an onium salt containing polymerizable unsaturated bonds. Preferred repeating units f include the repeating unit represented by the following general formula (f1) (hereinafter also referred to as repeating unit f1), the repeating unit represented by the following general formula (f2) (hereinafter also referred to as repeating unit f2), and the repeating unit represented by the following general formula (f3) (hereinafter also referred to as repeating unit f3). Repeating units f1 to f3 may be used individually or in combination of two or more types. [ka]

[0124] In the above general formulas (f1) to (f3), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to single bonds, aliphatic hydrocarbylene groups with 1 to 6 carbon atoms, phenylene groups, naphthylene groups, ester bonds, or groups with 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11 This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 These are single bonds or ester bonds. 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- Z 31This is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. 4 This is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, phenylene groups substituted with trifluoromethyl groups, -OZ 51 -, -C(=O)-OZ 51 -or -C(=O)-NH-Z 51 - is Z 51 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 15 carbon atoms, preferably 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may also be a combination thereof. It may also contain a carbonyl group, an ester bond, an ether bond, a halogen atom, and / or a hydroxyl group.

[0125] In the above general formulas (f1) to (f3), R 21 ~R 28 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, preferably 1 to 20 carbon atoms, which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the description of general formulas (1) and (1') above. 2 ~R 4 Examples of hydrocarbyl groups represented by the above include those similar to those exemplified. The above hydrocarbyl group may have some or all of its hydrogen atoms substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the carbon atoms of these groups may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result it may contain a hydroxyl group, fluorine atom, chlorine atom, bromine atom, iodine atom, cyano group, nitro group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic acid anhydride, haloalkyl group, etc. Also, R23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, examples of the above ring include the same rings as those exemplified as the rings that can be formed by bonding R 2 and R 3 and the sulfur atom to which they are bonded in the description of the above general formulas (1) and (1').

[0126] In the above general formula (f1), M - is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkyl sulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; aryl sulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkyl sulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion; methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0127] As other examples of the non-nucleophilic counter ion, there are sulfonate ions in which the α-position is substituted with a fluorine atom represented by the following general formula (f1-1), sulfonate ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group represented by the following general formula (f1-2), and the like. [Chemical formula]

[0128] In the above general formula (f1-1), R 31R is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0129] In the above general formula (f1-2), R 32 R is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 6 to 20 carbon atoms, and the hydrocarbyl group and hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl portion of the hydrocarbyl group and hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0130] Examples of monomer cations that give the repeating unit f1 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as above. [ka]

[0131] Specific examples of monomer cations that give repeating units f2 or f3 include those similar to those exemplified as cations of sulfonium salts represented by the general formulas (1) and (1') above.

[0132] Examples of monomer anions that give the repeating unit f2 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as above. [ka]

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139]

change

[0140]

change

[0141]

change

[0142]

change

[0143] [ka]

[0144] Examples of monomer anions that give the repeating unit f3 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as above. [ka]

[0145] [ka]

[0146] The repeating units f1 to f3 described above function as acid generators. By binding the acid generator to the polymer backbone, acid diffusion is reduced, preventing a decrease in resolution due to blurring caused by acid diffusion. Furthermore, the uniform dispersion of the acid generator improves LWR and CDU. When using a base polymer containing repeating unit f, the addition of the additive-type acid generator described later can be omitted.

[0147] In the above base polymer, the content ratios of repeating units a1, a2, b, c, d, e, f1, f2, and f3 are preferably 0≦a1≦0.9, 0≦a2≦0.9, 0≦a1+a2≦0.9, 0≦b≦0.9, 0≦c≦0.9, 0≦d≦0.5, 0≦e≦0.5, 0≦f1≦0.5, 0≦f2≦0.5, 0≦f3≦0.5, and 0≦f1+f2+f3≦0.5, and 0≦a1≦0.8, 0≦a2≦0.8, 0≦a1+a2≦0.8, 0 More preferably, the following are the conditions: ≤b≦0.8, 0≦c≦0.8, 0≦d≦0.4, 0≦e≦0.4, 0≦f1≦0.4, 0≦f2≦0.4, 0≦f3≦0.4, 0≦f1+f2+f3≦0.4. Even more preferably, the conditions are: 0≦a1≦0.7, 0≦a2≦0.7, 0≦a1+a2≦0.7, 0≦b≦0.7, 0≦c≦0.7, 0≦d≦0.3, 0≦e≦0.3, 0≦f1≦0.3, 0≦f2≦0.3, 0≦f3≦0.3, 0≦f1+f2+f3≦0.3, where a1+a2+b+c+d+f1+f2+f3+e=1.0.

[0148] To synthesize the above base polymer, for example, the monomer that provides the repeating units described above can be heated in an organic solvent with a radical polymerization initiator to carry out polymerization.

[0149] Organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0150] When copolymerizing monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acids such as ethoxyethoxy groups during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, they may be substituted with acetyl groups, formyl groups, pivaloyl groups, etc., and then subjected to alkaline hydrolysis after polymerization.

[0151] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0152] Ammonia water, triethylamine, etc., can be used as the base during alkaline hydrolysis. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0153] The above-mentioned base polymer has a polystyrene-based weight-average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 30,000, determined by gel permeation chromatography (GPC) using THF as a solvent. When Mw is within this range, the heat resistance and solubility in alkaline developers of the resist film are good.

[0154] Furthermore, if the molecular weight distribution (Mw / Mn) of the above-mentioned base polymer is sufficiently narrow, there are no low-molecular-weight or high-molecular-weight polymers, so there is no risk of foreign matter being observed on the pattern or the pattern shape deteriorating after exposure. As the pattern rule becomes finer, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the above-mentioned base polymer be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0155] The above base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0156] [Acid Generator] The resist material of the present invention may contain an acid generator that generates a strong acid (hereinafter also referred to as an additive-type acid generator). Here, a strong acid means a compound having sufficient acidity to cause a deprotection reaction of acid-unstable groups of the base polymer in the case of a chemically amplified positive-type resist material, and a compound having sufficient acidity to cause a polarity change reaction or crosslinking reaction by an acid in the case of a chemically amplified negative-type resist material. By including such an acid generator, the sulfonium salt A described above functions as a quencher, and the resist material of the present invention can function as a chemically amplified positive-type resist material or a chemically amplified negative-type resist material.

[0157] Examples of the acid-generating agents mentioned above include compounds that generate acid in response to active light or radiation (photoacid generators). Any compound that generates acid upon irradiation with high-energy rays can be used as a photoacid generator, but those that generate sulfonic acid, imido acid, or methidic acid are preferred. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of photoacid generators are those described in paragraphs

[0122] to

[0142] of Japanese Patent Publication No. 2008-111103.

[0158] Furthermore, sulfonium salts represented by the following general formula (3-1) and iodonium salts represented by the following general formula (3-2) can also be suitably used as photoacid generators. [ka]

[0159] In the above general formulas (3-1) and (3-2), R 101 ~R 105 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, preferably 1 to 20 carbon atoms, which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the explanation of general formulas (1) and (1') above. 2 ~R 4 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0160] Also, R 101 and R 102 These may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of general formulas (1) and (1') above. 2 and R 3 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0161] Examples of cations of the sulfonium salt represented by the above general formula (3-1) include those similar to those exemplified as cations of the sulfonium salt represented by the above general formulas (1) and (1').

[0162] The cations of the iodonium salt represented by the general formula (3-2) above include, but are not limited to, those listed below. [ka]

[0163] [ka]

[0164] In the above general formulas (3-1) and (3-2), Xa - This is an anion selected from the following general formulas (3A) to (3D). [ka]

[0165] In the above general formula (3A), R fa R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a fluorine atom or a heteroatom. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0166] The anion represented by the above general formula (3A) is preferably the one represented by the following general formula (3A'). [ka]

[0167] In the above general formula (3A'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.111 This is a hydrocarbyl group having 1 to 38 carbon atoms, which may contain heteroatoms. Preferred heteroatoms include oxygen, nitrogen, sulfur, and halogen atoms, with oxygen atoms being more preferred. The hydrocarbyl group is particularly preferred to have 6 to 30 carbon atoms, from the viewpoint of obtaining high resolution in fine pattern formation.

[0168] R 111 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C38 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosanyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, Examples include cyclic saturated hydrocarbyl groups with 3 to 38 carbon atoms, such as norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, and dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups with 2 to 38 carbon atoms, such as allyl group and 3-cyclohexenyl group; aryl groups with 6 to 38 carbon atoms, such as phenyl group, 1-naphthyl group, and 2-naphthyl group; aralkyl groups with 7 to 38 carbon atoms, such as benzyl group and diphenylmethyl group; and groups obtained by combining these.

[0169] Furthermore, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, they may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl groups, methoxymethyl groups, ethoxymethyl groups, methylthiomethyl groups, acetamidomethyl groups, trifluoroethyl groups, (2-methoxyethoxy)methyl groups, acetoxymethyl groups, 2-carboxy-1-cyclohexyl groups, 2-oxopropyl groups, 4-oxo-1-adamantyl groups, and 3-oxocyclohexyl groups.

[0170] For details on the synthesis of sulfonium salts containing the anion represented by the above general formula (3A'), please refer to Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. In addition, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc., can also be suitably used.

[0171] Examples of anions represented by the above general formula (3A) include those similar to those exemplified as anions represented by formula (1A) in Japanese Patent Publication No. 2018-197853.

[0172] In the above general formula (3B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the above general formula (3A'). 111Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 This refers to the groups that bond to each other (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0173] In the above general formula (3C), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the above general formula (3A'). 111 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 This refers to the groups that bond to each other (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0174] In the above general formula (3D), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the above general formula (3A'). 111Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0175] The synthesis of sulfonium salts containing the anion represented by the above general formula (3D) is described in detail in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0176] Examples of anions represented by the above general formula (3D) include those similar to those exemplified as anions represented by formula (1D) in Japanese Patent Publication No. 2018-197853.

[0177] Furthermore, the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, which gives it sufficient acidity to cleave acid-unstable groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0178] As a photoacid generator, one represented by the following general formula (4) can also be suitably used. [ka]

[0179] In the above general formula (4), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. 203 This is a hydrocarbylene group having 1 to 30 carbon atoms, which may contain heteroatoms. Also, R 201 , R 202 and R 203 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of general formulas (1) and (1') above. 2 and R 3 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0180] R 201 and R 202 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, and tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decanyl and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracenyl groups; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc.

[0181] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkane diyl groups with 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, etc.; cyclopentanediyl group, cyclohex Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl groups; arylene groups having 6 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc. Among the heteroatoms, oxygen atoms are preferred.

[0182] In the above general formula (4), L AThis is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The above hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 203 Examples of hydrocarbylene groups represented by the same formula as those exemplified above include the same groups as those shown.

[0183] In the above general formula (4), X A , X B , X C and X D Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X A , X B , X C and X D At least one of these is a fluorine atom or a trifluoromethyl group.

[0184] In the general formula (4) above, d is an integer between 0 and 3.

[0185] The photoacid generator represented by the above general formula (4) is preferably the one represented by the following general formula (4'). [ka]

[0186] In the above general formula (4'), L A The same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a hydrogen atom or a heteroatom. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A'). 111 Examples of hydrocarbyl groups represented by the formula shown are similar to those exemplified. x and y are each independent integers from 0 to 5, and z is an integer from 0 to 4.

[0187] Examples of photoacid generators represented by the above general formula (4) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0188] Among the above photoacid generators, those containing an anion represented by the above general formula (3A') or (3D) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (4') are particularly preferred because they exhibit extremely low acid diffusion.

[0189] As the above-mentioned photoacid generator, sulfonium salts or iodonium salts containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom can also be used. Examples of such salts are those represented by the following general formulas (5-1) or (5-2). [ka]

[0190] In the above general formulas (5-1) and (5-2), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, and more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0191] In the above general formulas (5-1) and (5-2), X BI These atoms are iodine atoms or bromine atoms, and when p and / or q are 2 or greater, they may be the same or different from each other.

[0192] In the above general formulas (5-1) and (5-2), L 1 This is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which may contain a single bond, an ether bond, or an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0193] In the above general formulas (5-1) and (5-2), L2 When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p+1) valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, a halogen atom, or a nitrogen atom.

[0194] In the above general formulas (5-1) and (5-2), R 401 This may include a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, an ester bond, or an amide bond, and may contain a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group, or a C1-C20 hydrocarbylsulfonyloxy group, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D That is. R 401A and R 401B Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401DThis is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The above aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The above saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 They may be the same or different from one another.

[0195] Of these, R 401 Examples include hydroxyl groups, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0196] In the above general formulas (5-1) and (5-2), Rf 1 ~Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 1 and Rf 2 These may combine to form a carbonyl group. In particular, Rf 3 and Rf 4 It is preferable that both are fluorine atoms.

[0197] In the above general formulas (5-1) and (5-2), R 402 ~R 406Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of general formulas (1) and (1') above, R 2 ~R 3 Examples of hydrocarbyl groups represented by are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with hydroxyl groups, carboxyl groups, halogen atoms, cyano groups, nitro groups, mercapto groups, sultone rings, sulfone groups, or sulfonium salt-containing groups, and some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate bonds, or sulfonic acid ester bonds. In addition, R 402 and R 403 These may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the above ring is R as described in the explanation of formulas (1) and (1'). 2 and R 3 Examples of rings that can be formed when these elements bond with each other, together with the sulfur atom to which they bond, are similar to those exemplified above.

[0198] Examples of cations for the sulfonium salt represented by the above general formula (5-1) are the same as those exemplified for the cations of the sulfonium salt represented by the above general formulas (1) and (1'). Similarly, examples of cations for the iodonium salt represented by the above general formula (5-2) are the same as those exemplified for the cations of the iodonium salt represented by formula (3-2).

[0199] The anions of the onium salt represented by the above general formula (5-1) or (5-2) include, but are not limited to, those listed below. Note that in the following formulas, X BI This is the same as above. [ka]

[0200]

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[0201]

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[0202]

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[0203]

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[0204]

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[0205]

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[0206]

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[0207]

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[0208]

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[0209]

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[0210]

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[0211]

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[0212]

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[0213]

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[0214]

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[0216]

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[0217]

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[0222] When the resist material of the present invention contains an additive-type acid generator, its content is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The resist material of the present invention can function as a chemically amplified resist material by the fact that the base polymer contains any of the repeating units f1 to f3 and / or contains an additive-type acid generator.

[0223] [Organic solvents] The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the components described above and the components described later. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol Examples include ethers such as monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0224] In the resist material of the present invention, the content of the above-mentioned organic solvent is preferably 100 to 10,000 parts by mass, and more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer. The above-mentioned organic solvent may be used alone or as a mixture of two or more types.

[0225] [Other ingredients] In addition to the components described above, the resist material of the present invention may also contain surfactants, dissolution inhibitors, crosslinking agents, quenchers other than sulfonium salt A (hereinafter referred to as "other quenchers"), water-repellency enhancers, acetylene alcohols, and the like.

[0226] Examples of the surfactants mentioned above include those described in paragraphs

[0165] to

[0166] of Japanese Patent Publication No. 2008-111103. By adding a surfactant, the coatability of the resist material can be further improved or controlled. When the resist material of the present invention contains the surfactant, its content is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more types.

[0227] When the resist material of the present invention is of the positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by incorporating a dissolution inhibitor, thereby further improving the resolution. Examples of the above-mentioned dissolution inhibitor include compounds in which the hydrogen atoms of the phenolic hydroxyl groups of a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule are substituted with acid-unstable groups in a total proportion of 0 to 100 mol%, or compounds in which the hydrogen atoms of the carboxyl groups of a compound containing a carboxyl group in the molecule are substituted with acid-unstable groups in an average total proportion of 50 to 100 mol%. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl group or carboxyl group of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-unstable groups, as described in paragraphs

[0155] to

[0178] of Japanese Patent Application Publication No. 2008-122932.

[0228] When the resist material of the present invention is of the positive type and contains the above-mentioned dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the base polymer. The above-mentioned dissolution inhibitor may be used alone or in combination of two or more types.

[0229] On the other hand, if the resist material of the present invention is negative type, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluryl compounds, urea compounds, isocyanate compounds, azide compounds, or compounds containing double bonds such as alkenyloxy groups, which are substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives or introduced as pendant groups in the polymer side chains. Compounds containing hydroxyl groups can also be used as crosslinking agents.

[0230] Examples of the epoxy compounds mentioned above include tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0231] Examples of the above-mentioned melamine compounds include hexamethylmelamine, hexamethoxymethylmelamine, compounds in which 1 to 6 methylol groups of hexamethylmelamine are methoxymethylated or mixtures thereof, hexamethoxyethylmelamine, hexaacyloxymethylmelamine, compounds in which 1 to 6 methylol groups of hexamethylmelamine are acyloxymethylated or mixtures thereof.

[0232] Examples of the above guanamine compounds include tetramethylolguanamine, tetramethoxymethylguanamine, compounds in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated or mixtures thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, compounds in which 1 to 4 methylol groups of tetramethylolguanamine are acyloxymethylated or mixtures thereof.

[0233] Examples of the glycoluryl compounds mentioned above include tetramethylol glycoluryl, tetramethoxy glycoluryl, tetramethoxymethyl glycoluryl, compounds in which 1 to 4 methylol groups of tetramethylol glycoluryl are methoxymethylated or mixtures thereof, compounds in which 1 to 4 methylol groups of tetramethylol glycoluryl are acyloxymethylated or mixtures thereof.

[0234] Examples of the above-mentioned urea compounds include tetramethylolurea, tetramethoxymethylurea, compounds in which 1 to 4 methylol groups of tetramethylolurea are methoxymethylated or mixtures thereof, and tetramethoxyethylurea.

[0235] Examples of the above-mentioned isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0236] Examples of the above-mentioned azide compounds include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0237] Examples of compounds containing the above-mentioned alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0238] When the resist material of the present invention is of the negative type and contains the above-mentioned crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The above-mentioned crosslinking agent may be used alone or in combination of two or more types.

[0239] Other quenchers mentioned above include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, or tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, etc. Particularly preferred are primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103, especially amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent Publication No. 3790649. By adding such basic compounds, for example, the diffusion rate of acid in the resist film can be further suppressed or its shape corrected.

[0240] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids whose α-position is not fluorinated, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imido acids, or methidic acids with α-position fluorinated are necessary for deprotecting the acid-unstable group of carboxylic acid esters, but salt exchange with onium salts whose α-position is not fluorinated releases sulfonic acids or carboxylic acids whose α-position is not fluorinated. Since sulfonic acids and carboxylic acids whose α-position is not fluorinated do not undergo deprotection reactions, they function as quenchers.

[0241] Other quenchers include the polymer-type quencher described in Japanese Patent Publication No. 2008-239918. This enhances the rectangularity of the resist pattern by oriented on the surface of the resist film. Polymer-type quenchers also have the effect of preventing film thinning of the pattern and rounding of the pattern top when a protective film for immersion lithography is applied.

[0242] If the resist material of the present invention contains other quenchers, their content is preferably 0 to 5 parts by mass, and more preferably 0 to 4 parts by mass, per 100 parts by mass of the base polymer. The other quenchers may be used alone or in combination of two or more.

[0243] The above-mentioned water-repellency improving agent improves the water repellency of the resist film surface and can be used in immersion lithography without a topcoat. Preferred water-repellency improving agents include polymers containing alkyl fluoride, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and those exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more preferred. The above-mentioned water-repellency improving agent needs to be dissolved in an alkaline developer or an organic solvent developer. The water-repellency improving agent having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water-repellency improving agent, polymers containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation during post-exposure baking (PEB) and preventing poor hole pattern opening after development. When the chemically amplified resist material of the present invention contains the above-mentioned water-repellency improving agent, its content is preferably 0 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the base polymer. The above-mentioned water-repellency improving agent may be used alone or in combination of two or more types.

[0244] Examples of the above-mentioned acetylene alcohols include those described in paragraphs

[0179] to

[0182] of Japanese Patent Publication No. 2008-122932. When the chemical amplification resist material of the present invention contains the above-mentioned acetylene alcohols, the content is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The above-mentioned acetylene alcohols may be used individually or in combination of two or more types.

[0245] [Pattern formation method] When the resist material of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method may include a step of forming a resist film on a substrate using the chemically amplified resist material described above, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0246] First, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the coating film thickness is 0.01 to 2 μm. This is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0247] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far ultraviolet rays, electron beams (EB), extreme ultraviolet rays (EUV) with wavelengths of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation as the high-energy rays, the exposure amount is preferably 1 to 200 mJ / cm², either directly or using a mask to form the desired pattern. 2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent of [a certain degree]. When using EB as the high-energy beam, the exposure dose is preferably 0.1 to 300 μC / cm². 2 To a degree, more preferably 0.5 to 200 μC / cm² 2The pattern is drawn either directly or using a mask to form the desired pattern. The resist material of the present invention is particularly suitable for fine patterning using high-energy rays, including KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, gamma rays, and synchrotron radiation. In particular, KrF excimer laser light, ArF excimer laser light, EB, or EUV with a wavelength of 3 to 15 nm is preferred, and it is especially suitable for fine patterning using EB or EUV.

[0248] After exposure, PEB may be performed on a hot plate or in an oven, preferably at 30-150°C for 10 seconds to 30 minutes, more preferably at 50-120°C for 30 seconds to 20 minutes, or it may not be performed.

[0249] After exposure or PEB, the exposed resist film is developed using a developer solution containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as the dip method, puddle method, or spray method, thereby forming the desired pattern. In the case of positive-type resist materials, the areas irradiated with light dissolve in the developer solution, while the unexposed areas do not dissolve, forming the desired positive-type pattern on the substrate. In the case of negative-type resist materials, the opposite is true: the areas irradiated with light become insoluble in the developer solution, while the unexposed areas dissolve.

[0250] Negative patterns can also be obtained by developing with organic solvents using positive-type resist materials containing a base polymer with acid-unstable groups. The developers used in this process include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotate, ethyl crotate, Examples include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenyl acetate, and 2-phenylethyl acetate. These organic solvents may be used individually or in mixtures of two or more.

[0251] At the end of development, rinsing is performed. A solvent that mixes with the developer but does not dissolve the resist film is preferred as the rinsing solution. Preferred solvents include C3-C10 alcohols, C8-C12 ether compounds, C6-C12 alkanes, alkenes, alkynes, and aromatic solvents.

[0252] The above C3-C10 alcohols include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, Examples include 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0253] Examples of the above-mentioned ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0254] Examples of alkanes with 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of alkenes with 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of alkynes with 6 to 12 carbon atoms include hexine, heptine, and octine.

[0255] Examples of the above aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0256] Rinsing can reduce the occurrence of deformation and defects in the resist pattern. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0257] The developed hole patterns and trench patterns can also be shrunk using thermal flow, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the side walls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[0258] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0259] The structures of the quenchers Q-1 to Q-28 used in the resist material are shown below.

[0260] [ka]

[0261] [ka]

[0262] [ka]

[0263] [Synthesis Example] Synthesis of base polymers (polymers 1-5) Each monomer was combined and copolymerized in THF, a solvent, crystallized in methanol, and then repeatedly washed with hexane before isolation and drying to obtain base polymers (polymers 1-5) with the following compositions. The compositions of the obtained base polymers are: 1 Mw and Mw / Mn were confirmed by H-NMR using GPC (solvent: THF, standard: polystyrene). [ka]

[0264] [ka]

[0265] [Examples 1-32, Comparative Examples 1-4] Preparation and Evaluation of Resist Materials (1) Preparation of resist material The resist materials were prepared by dissolving each component in the compositions shown in Tables 1 and 2, and then filtering the solutions through a 0.2 μm filter. The resist materials of Examples 1-20, 22-32, and Comparative Examples 1-3 were positive type, while the resist materials of Example 21 and Comparative Example 4 were negative type.

[0266] In Tables 1 and 2, the components are as follows: • Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (Ethyl Lactate)

[0267] • Acid generators: PAG-1 to PAG-5 [ka]

[0268] • Blend Quencher: bQ-1, bQ-2 [ka]

[0269] • Comparative quenchers: cQ-1, cQ-2, cQ-3 [ka]

[0270] (2) EUV lithography evaluation Each resist material shown in Tables 1 and 2 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. A resist film with a thickness of 60 nm was then fabricated by pre-baking at 100°C for 60 seconds using a hot plate. Next, the resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimensions of 44 nm pitch, +20% bias hole pattern mask). PEB was performed on a hot plate at the temperatures listed in Tables 1 and 2 for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds. This resulted in hole patterns with dimensions of 22 nm in Examples 1-20, 22-32, and Comparative Examples 1-3, and dot patterns with dimensions of 22 nm in Example 21 and Comparative Example 4. Using a Hitachi High-Technologies Corporation length-measuring SEM (CG6300), the exposure amount when a hole or dot dimension of 22 nm was formed was measured and defined as the sensitivity. The dimensions of 50 holes or dots were also measured, and the CDU was defined as three times the standard deviation (σ) calculated from these measurements (3σ). The results are shown in Tables 1 and 2.

[0271] [Table 1]

[0272] [Table 2]

[0273] The results shown in Tables 1 and 2 indicate that the resist material of the present invention, which contains one or more of the following as a quencher: a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethoxy)benzoic acid and / or a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethylthio)benzoic acid, or a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethylthio)benzoic acid, a 2- or 3-di or trifluoromethoxybenzoic acid sulfonium salt, and a 2- or 3-di or trifluoromethylthiobenzoic acid sulfonium salt, exhibits high sensitivity and improved CDU.

[0274] This specification includes the following embodiments: [1]: As a quencher, A resist material characterized by comprising a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethoxy)benzoic acid, and / or a substituted or unsubstituted sulfonium salt of hydroxy(trifluoromethylthio)benzoic acid. [2]: The resist material according to [1] above, characterized in that the sulfonium salt of the substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid, and / or the sulfonium salt of the substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid is represented by the following general formula (1). [ka] (In the formula, R 1 is a hydrogen atom, or a group selected from linear, branched, or cyclic alkyl, alkoxy, alkoxycarbonyl, or acyl groups having 1 to 15 carbon atoms, or alkenyl or alkynyl groups having 2 to 15 carbon atoms. The group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl or hydroxyl group, and may be an acid-unstable group. X is an oxygen atom or a sulfur atom. m and n are 1 or 2, respectively. R 2 ~R 4Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 2 and R 3 However, they may bond to each other, forming a ring with the sulfur atom to which they are bonded. [3]: As a quencher, A resist material characterized by containing one or more of the following: a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethoxy)benzoic acid, a substituted or unsubstituted sulfonium salt of hydroxy(difluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethoxybenzoic acid, and a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid. [4]: The resist material according to [3] above, characterized in that one or more of the substituted or unsubstituted sulfonium salts of hydroxy(difluoromethoxy)benzoic acid, substituted or unsubstituted sulfonium salts of hydroxy(difluoromethylthio)benzoic acid, sulfonium salts of 2- or 3-di or trifluoromethoxybenzoic acid, and sulfonium salts of 2- or 3-di or trifluoromethylthiobenzoic acid are represented by the following general formula (1'). [ka] (In the formula, R 1´ The group is selected from a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted amino group, or a linear, branched, or cyclic alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, alkenyloxy group, or alkynyloxy group having 1 to 15 carbon atoms, and the group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may be an acid-unstable group, but R 1´ If it is a hydrogen atom, then F q H p The substitution position of the CX- group is at position 2 or 3. p is 0 or 1, q is 2 or 3. X is an oxygen atom or a sulfur atom. m and n are each 1 or 2. R2 ~R 4 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 2 and R 3 However, they may bond to each other, forming a ring with the sulfur atom to which they are bonded. [5]: The resist material according to any one of [1] to [4] above, further characterized by containing an acid generator that generates acid. [6]: The resist material according to [5] above, characterized in that the acid generating agent generates sulfonic acid, imido acid, or methidoic acid. [7]: The resist material according to any one of [1] to [6] above, further characterized by containing an organic solvent. [8]: The resist material according to any one of [1] to [7] above, further characterized by containing a base polymer. [9]: The resist material according to [8] above, characterized in that the base polymer includes repeating units represented by the following general formula (a1) and / or repeating units represented by the following general formula (a2). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 These are single bonds or ester bonds. 3 These are single bonds, ether bonds, or ester bonds. 11 and R 12 These are, independently, acid-unstable groups. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of which may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

[10] : The resist material according to [9] above, characterized in that the resist material is a chemically amplified positive resist material.

[11] : The resist material according to [8] above, characterized in that the base polymer does not contain acid-unstable groups.

[12] : The resist material according to

[11] above, characterized in that the resist material is a chemically amplified negative resist material.

[13] : The resist material according to any one of [8] to

[12] above, characterized in that the base polymer further comprises at least one selected from repeating units represented by the following general formulas (f1) to (f3). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to single bonds, aliphatic hydrocarbylene groups with 1 to 6 carbon atoms, phenylene groups, naphthylene groups, ester bonds, or groups with 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11 This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 These are single bonds or ester bonds. 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- Z 31This is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. 4 This is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, phenylene groups substituted with trifluoromethyl groups, -OZ 51 -, -C(=O)-OZ 51 -or -C(=O)-NH-Z 51 - is Z 51 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 15 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may also be a combination thereof, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom and / or a hydroxyl group. 21 ~R 28 Each of these is independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. 23 and R 24 or R 26 and R 27 These may be bonded to each other, forming a ring with the sulfur atom to which they are bonded. - (It is a non-nucleophilic counterion.)

[14] : The resist material according to any one of [1] to

[13] above, further characterized by containing a surfactant.

[15] : A pattern forming method characterized by comprising the steps of forming a resist film on a substrate using a resist material described in any of [1] to

[14] above, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[16] : The pattern formation method according to

[15] above, characterized in that the high-energy beam is KrF excimer laser light, ArF excimer laser light, electron beam or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0275] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. As a quencher, A resist material characterized by comprising a sulfonium salt of substituted or unsubstituted hydroxy(trifluoromethoxy)benzoic acid, and / or a sulfonium salt of substituted or unsubstituted hydroxy(trifluoromethylthio)benzoic acid, represented by the following general formula (1). 【Chemistry 1】 (In the formula, R1 is a hydrogen atom, or a group selected from linear, branched, or cyclic alkyl, alkoxy, alkoxycarbonyl, or acyl groups having 1 to 15 carbon atoms, or alkenyl or alkynyl groups having 2 to 15 carbon atoms. The group may contain a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may also be an acid-unstable group. X is an oxygen atom or a sulfur atom. m and n are each 1 or 2. R2 to R4 are each independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. R2 and R3 may also be bonded to each other to form a ring with the sulfur atom to which they are bonded.)

2. As a quencher, A resist material characterized by containing one or more of the following, represented by the general formula (1'): a sulfonium salt of substituted or unsubstituted hydroxy(difluoromethoxy)benzoic acid, a sulfonium salt of substituted or unsubstituted hydroxy(difluoromethylthio)benzoic acid, a sulfonium salt of 2- or 3-di or trifluoromethoxybenzoic acid, and a sulfonium salt of 2- or 3-di or trifluoromethylthiobenzoic acid. 【Chemistry 2】 (In the formula, R 1' is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted amino group, or a linear, branched, or cyclic alkyl group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, alkenyloxy group, or alkynyloxy group having 1 to 15 carbon atoms. The group may have a halogen atom, a carbonyl group, an ether bond, a substituted or unsubstituted aryl group, or a hydroxyl group, and may be an acid-unstable group. However, if R 1' is a hydrogen atom, the substitution position of the C-X- group is at position 2 or 3. p is 0 or 1, q is 2 or 3. X is an oxygen atom or a sulfur atom. m and n are 1 or 2, respectively. R 2 to R 4 are each independently a hydrocarbyl group having 1 to 25 carbon atoms, which may contain a halogen atom or a heteroatom. Also, R 2 (And R3 may bond to each other, forming a ring with the sulfur atom to which they are bonded.)

3. Furthermore, the resist material according to claim 1 is characterized by containing an acid generator that produces acid.

4. The resist material according to claim 3, characterized in that the acid generating agent generates sulfonic acid, imido acid, or methidoic acid.

5. Furthermore, the resist material according to claim 1 is characterized in that it contains an organic solvent.

6. Furthermore, the resist material according to claim 3 is characterized in that it contains an organic solvent.

7. Furthermore, the resist material according to claim 1 is characterized in that it further contains a base polymer.

8. Furthermore, the resist material according to claim 3, characterized in that it further contains a base polymer.

9. Furthermore, the resist material according to claim 5 is characterized in that it further contains a base polymer.

10. The resist material according to claim 7, characterized in that the base polymer includes repeating units represented by the following general formula (a1) and / or repeating units represented by the following general formula (a2). 【Transformation 3】 (In the formula, R Ａ Each of these is independently either a hydrogen atom or a methyl group. １ This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. ２ These are single bonds or ester bonds. ３ This is a single bond, an ether bond, or an ester bond. １１ and R １２ These are, independently, acid-unstable groups. １３ R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. １４ a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of its carbon atoms may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

11. The resist material according to claim 10, characterized in that the resist material is a chemically amplified positive-type resist material.

12. The resist material according to claim 7, characterized in that the base polymer does not contain acid-unstable groups.

13. The resist material according to claim 12, characterized in that the resist material is a chemically amplified negative resist material.

14. The resist material according to claim 7, characterized in that the base polymer further comprises at least one selected from repeating units represented by the following general formulas (f1) to (f3). 【Chemistry 4】 (In the formula, R Ａ is each independently a hydrogen atom or a methyl group. Z １ is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, an ester bond or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z １１ -, -C(=O)-O-Z １１ - or -C(=O)-NH-Z １１ -. Z １１ is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. Z ２ is a single bond or an ester bond. Z ３ is a single bond, -Z ３１ -C(=O)-O-, -Z ３１ -O- or -Z ３１ -O-C(=O)-. Z ３１ is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom or a bromine atom. Z ４ is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z ５ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z ５１ -, -C(=O)-O-Z ５１ - or -C(=O)-NH-Z ５１ -. Z ５１ is an aliphatic hydrocarbylene group having 1 to 15 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, or a combination thereof, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom and / or a hydroxy group. R ２１ ~R ２８ is each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms which may contain a hetero atom. Also, R ２３ and R ２４ or R ２６ and R ２７ These may be bonded to each other, forming a ring with the sulfur atom to which they are bonded. － (It is a non-nucleophilic counterion.)

15. Furthermore, the resist material according to claim 1 is characterized by containing a surfactant.

16. A pattern forming method characterized by comprising the steps of: forming a resist film on a substrate using a resist material according to any one of claims 1 to 15; exposing the resist film with a high-energy beam; and developing the exposed resist film using a developer.

17. The pattern formation method according to claim 16, characterized in that the high-energy beam used is KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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