Resist material and pattern formation method

Abstract

To provide a resist material which has high sensitivity and improved LWR and CDU, and a pattern formation method using the same.SOLUTION: The resist material contains a quencher containing a sulfonium salt represented by the formula (1) in the figure.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 spread of 5G high-speed communication and artificial intelligence (AI) is advancing, requiring 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, and IMEC in Belgium has announced the development of 1nm and 0.7nm 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 (LWR) in a triangle trade-off is shown. 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] To form finer patterns, it is necessary not only to suppress acid diffusion but also to improve dissolution contrast. To improve dissolution contrast, polarity-converting base polymers that generate phenolic or carboxyl groups through acid-induced deprotection reactions are used. Using resist materials containing these polymers, positive patterns can be formed by alkaline development, and negative patterns by organic solvent development, but positive patterns have higher resolution. This is because alkaline development results in higher dissolution contrast. Furthermore, base polymers that generate carboxyl groups have higher alkali solubility than base polymers that generate phenolic groups, and thus higher dissolution contrast can be obtained. For this reason, carboxyl-generating base polymers are increasingly being used.

[0007] Non-chemically amplified resist materials with a main chain decomposition type, where the main chain decomposes upon exposure, reducing molecular weight and improving solubility in organic solvent developers, are not affected by acid diffusion but have low dissolution contrast. Chemically amplified resist materials with the aforementioned polarity conversion function have higher resolution.

[0008] To further improve dissolution contrast, it has been proposed to add an acid generator with polarity conversion capabilities to the resist material, in addition to a base polymer with polarity conversion capabilities. Patent documents 3 and 4 show resist materials containing sulfonium salts having a tertiary ester-type acid-unstable group in the cationic portion, and patent documents 5 and 6 show resist materials containing sulfonium salts having an acid-unstable group in the anionic portion. However, the alicyclic structure type and dimethylphenylcarbinol type acid-unstable groups described in these documents were insufficient in improving dissolution contrast and reducing swelling. [Prior art documents] [Patent Documents]

[0009] [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. 2011-006400 [Patent Document 4] Japanese Patent Publication No. 2021-070692 [Patent Document 5] Japanese Patent Publication No. 2014-224236 [Patent Document 6] International Publication No. 2021 / 200056 [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] 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 enhancing sensitivity. To achieve this, it is necessary to further improve the dissolution contrast during development.

[0012] The present invention has been made in view of the above circumstances, and aims to provide a resist material that is highly sensitive and has improved LWR and CDU, particularly in positive-type resist materials, and a pattern formation method using the same. [Means for solving the problem]

[0013] As a result of diligent research to achieve the above objective, the inventors have discovered that a resist material containing a sulfonium salt of a weak acid having a tertiary ester-type acid unstable group with a triple bond in the cation portion as a quencher exhibits excellent diffusion control of the acid generated from the acid generator and high affinity with alkaline developers, resulting in high contrast and low swelling properties. This leads to improved LWR and CDU, and a resist material with excellent resolution and a wide process margin, thus completing the present invention.

[0014] In other words, the present invention provides the following resist material and pattern formation method. 1. A resist material comprising a quencher containing a sulfonium salt represented by the following formula (1). [ka] (In the formula, p is 0 or 1, q is an integer from 0 to 4, r is 1 or 2, and s is an integer from 1 to 3.) R 1 These are single bonds, ether bonds, thioether bonds, or ester bonds. R 2 This is a single bond or an alkanediyl group having 1 to 20 carbon atoms, and the alkanediyl group may have a fluorine atom or a hydroxyl group. R 3 and R 4is, independently of one another, a saturated hydrocarbyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the saturated hydrocarbyl group, alkenyl group, alkynyl group and aryl group may contain an oxygen atom or a sulfur atom. Also, R 3 and R 4 may combine with each other to form a ring together with the carbon atom to which they are attached. R 5 is a hydrogen atom, a saturated hydrocarbyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms, and the saturated hydrocarbyl group and aryl group may have at least one selected from the group consisting of a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an amino group, a trifluoromethyl group, a trifluoromethoxy group and a trifluoromethylthio group. However, when R 3 is a substituted or unsubstituted phenyl group, R 5 is not a hydrogen atom. R 6 is a hydroxy group, a carboxy group, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms which may contain at least one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group and an ether bond. R 7 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. When s = 1, the two R 7 may be the same as or different from each other, and may combine with each other to form a ring together with the sulfur atom to which they are attached. X - is a non-nucleophilic counter ion weaker than sulfonic acid.) 2.X -A resist material 1 in which the non-nucleophilic counterion represented by is a carboxylic acid anion, a sulfonamide anion, a fluorine-free methidoate anion, a phenoxide anion, a halide anion, or a carbonate anion. 3. A resist material of type 2, wherein the carboxylic acid anion is represented by the following formula (2)-1, the sulfonamide anion is represented by the following formula (2)-2, the fluorine atom-free methidoic acid anion is represented by the following formula (2)-3, and the phenoxide anion is represented by the following formula (2)-4. [ka] (In the formula, R 11 This is a hydrocarbyl group having 1 to 24 carbon atoms, which may contain a hydrogen atom, a fluorine atom, or a heteroatom. R 12 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. R 13 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. R 14 ~R 16 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms. R 17 These are halogen atoms, hydroxyl groups, cyano groups, nitro groups, amino groups, C2-C10 alkylcarbonylamino groups, C1-C10 alkylsulfonylamino groups, C1-C10 alkylsulfonyloxy groups, C1-C10 alkyl groups, phenyl groups, C1-C10 alkoxy groups, C1-C10 alkylthio groups, C2-C10 alkoxycarbonyl groups, C1-C10 acyl groups, or C1-C10 acyloxy groups, and some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with fluorine atoms. k is an integer between 0 and 5. 4. A resist material containing one of the following 1-3, which also contains an acid generator that produces a strong acid. 5. The resist material of 4, wherein the strong acid is a sulfonic acid, a fluorinated imido acid, or a fluorinated methido acid. 6. Furthermore, one of the resist materials 1-5 containing an organic solvent. 7. Furthermore, any of the resist materials 1 to 6, including a base polymer. 8. The resist material of 7, wherein the base polymer contains repeating units represented by the following formula (a1) or the following formula (a2). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. X 1 This is a linking group having 1 to 12 carbon atoms that includes a single bond, a phenylene group or a naphthylene group, or at least one selected from an ester bond, an ether bond, and a lactone ring. X 2 These are single bonds or ester bonds. X 3 These are single bonds, ether bonds, or ester bonds. R 21 and R 22 These are, independently, acid-unstable groups. R 23 These are a fluorine atom, a trifluoromethyl group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 7 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms, or a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms. R 24 This is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and a portion of the -CH2- of the alkanediyl group may be substituted with an ether bond or an ester bond. a is either 1 or 2. b is an integer between 0 and 4, where 1 ≤ a + b ≤ 5. 9. A resist material of type 8, which is a chemically amplified positive resist material. 10. A resist material of any of the 7 to 9, wherein the base polymer comprises at least one repeating unit selected from the following formulas (f1) to (f3). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. Z 1 This refers to a single bond, 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, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11 This refers to 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 hydroxyl group. Z 2 These are single bonds or ester bonds. Z 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- Z 31 This refers to an aliphatic 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 This group is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 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 51This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxyl group, or a halogen atom. R 31 ~R 38 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 33 and R 34 or R 36 and R 37 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. M - (It is a non-nucleophilic counterion.) 11. Furthermore, any of the resist materials 1 to 10 containing a surfactant. A pattern forming method comprising the steps of: forming a resist film on a substrate using any of the resist materials from 12.1 to 11; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer. 13. A pattern formation method wherein the high-energy beam is a KrF excimer laser beam, an ArF excimer laser beam, an electron beam (EB), or an EUV beam with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0015] The quencher, a weak acid sulfonium salt having a tertiary ester-type acid-unstable group with a triple bond as a cation, not only excels at controlling the diffusion of acid generated from the acid generator upon exposure when a base polymer containing the acid-unstable group is added, but also improves the alkali dissolution rate due to the polarity change of the acid-unstable group of the base polymer through an acid-catalyzed reaction. Furthermore, the quencher itself, in its unexposed portions, does not dissolve in the developer, and carboxyl groups are generated by the acid generated from the acid generator upon exposure, further improving the alkali dissolution rate. As a result, it is possible to construct a resist material with improved LWR and CDU. [Modes for carrying out the invention]

[0016] [Resist material] The resist material of the present invention comprises a quencher containing a sulfonium salt of a weak acid having a tertiary ester-type acid-unstable group with a triple bond as a cation.

[0017] [Sulfonium salts of weak acids having a tertiary ester-type acid-unstable group with a triple bond as a cation] The sulfonium salt of a weak acid having a tertiary ester-type acid-unstable group with a triple bond as a cation is represented by the following formula (1). [ka]

[0018] In equation (1), p is 0 or 1, q is an integer between 0 and 4, r is 1 or 2, and s is an integer between 1 and 3.

[0019] In formula (1), R 1 The bond is a single bond, an ether bond, a thioether bond, or an ester bond, with ether bonds or ester bonds being preferred.

[0020] In formula (1), R 2 The alkanediyl group is a single bond or an alkanediyl group having 1 to 20 carbon atoms, and the alkanediyl group may have a fluorine atom or a hydroxyl group. The alkanediyl group may be a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, or a butane-1,4- Examples include diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl group, 2-methylbutane-1,2-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, and dodecane-1,12-diyl group.

[0021] In formula (1), R 3 and R 4 Each of these is independently a saturated hydrocarbyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the saturated hydrocarbyl group, alkenyl group, alkynyl group, and aryl group may contain an oxygen atom or a sulfur atom. Also, R 3 and R 4 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded.

[0022] R 3 and R 4 The saturated hydrocarbyl group having 1 to 12 carbon atoms, represented by , may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 12 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. 3 and R 4 Examples of alkenyl groups with 2 to 8 carbon atoms represented by include vinyl groups, 1-propenyl groups, 2-propenyl groups, butenyl groups, and hexenyl groups. 3 and R 4 Examples of alkynyl groups with 2 to 8 carbon atoms represented by include the ethynyl group and the butynyl group. 3 and R 4 Examples of aryl groups with 6 to 12 carbon atoms represented by this formula include phenyl groups and naphthyl groups.

[0023] In formula (1), R 5R is a hydrogen atom, a saturated hydrocarbyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms, and the saturated hydrocarbyl group and aryl group may have at least one selected from a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an amino group, a trifluoromethyl group, a trifluoromethoxy group, and a trifluoromethylthio group. However, R 3 When R is a substituted or unsubstituted phenyl group, 5 It is not a hydrogen atom.

[0024] R 5 The saturated hydrocarbyl group having 1 to 12 carbon atoms, represented by R, can be linear, branched, or cyclic, and a specific example is R 3 and R 4 Examples of saturated hydrocarbyl groups with 1 to 12 carbon atoms, as shown in the example, are similar to those exemplified by R. 5 Examples of aryl groups with 6 to 18 carbon atoms represented by include phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, 2,4-dimethylphenyl group, 2,4,6-trimethylphenyl group, naphthyl group, anthryl group, phenalenyl group, pyrenyl group, indanyl group, fluorenyl group, and the like.

[0025] In formula (1), R 6 This is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, which may contain at least one selected from a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxyl group, an amino group, and an ether bond.

[0026] R6 The saturated hydrocarbyl portion of saturated hydrocarbyl groups, saturated hydrocarbyloxy groups, saturated hydrocarbylcarbonyloxy groups, saturated hydrocarbyloxycarbonyl groups, and saturated hydrocarbylsulfonyloxy groups represented by can be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-pentadecyl, and n-hexadecyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl.

[0027] In formula (1), R 7 This is a C1-C20 hydrocarbyl group, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include a C1-C20 saturated hydrocarbyl group, a C2-C20 unsaturated aliphatic hydrocarbyl group, a C6-C20 aryl group, a C7-C20 aralkyl group, and groups obtained by combining these.

[0028] The saturated hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-pentadecyl, and n-hexadecyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl.

[0029] The aforementioned unsaturated aliphatic hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; alkynyl groups such as ethynyl, propynyl, and butynyl groups; and cyclic unsaturated hydrocarbyl groups such as cyclohexenyl groups.

[0030] Examples of the aryl group include phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group, and the like.

[0031] Examples of the aforementioned aralkyl group include the benzyl group and the phenethyl group.

[0032] 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- groups 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, the group may contain a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, an amino group, a nitro group, a sultone ring, a sulfo group, a sulfonium salt-containing group, an ether bond, an ester bond, a carbonyl group, a sulfide bond, a sulfonyl group, an amide bond, and the like.

[0033] When s=1, the two R 7 These elements may be identical or different, and they may bond together to form a ring with the sulfur atom to which they are bonded. In this case, the ring is preferably structured as shown below. [ka] (In the formula, the dashed lines represent the bonds with the aromatic ring in formula (1).)

[0034] The base polymer and the sulfonium salt exhibit even higher dissolution contrast when their acid-unstable groups undergo a deprotection reaction catalyzed by an acid catalyst and dissolve in the alkaline developer. This enables even higher sensitivity and improvements in low LWR and CDU. Furthermore, the exposure level at which the base polymer's solubility improves due to the deprotection reaction is the same as the exposure level at which the sulfonium salt dissolves, further enhancing contrast.

[0035] When the acid-unstable group of the base polymer and the acid-unstable group of the sulfonium salt have the same structure, the sulfonium salt present near the generated acid is more likely to undergo the deprotection reaction. Even if the deprotection reactions occur simultaneously, the sulfonium salt with a smaller molecular weight dissolves more readily in alkaline developer at lower exposure levels. Conventional sulfonium salts substituted with acid-unstable groups had acid-unstable groups similar to those of the base polymer, resulting in a gap in the deprotection reactivity between the base polymer and the sulfonium salt, which led to a low dissolution contrast improvement effect.

[0036] In this invention, in order to eliminate the gap in deprotection reactivity between the base polymer and the sulfonium salt, it is preferable to use an acid-unstable group of the sulfonium salt that has lower deprotection reactivity than the acid-unstable group of the base polymer. For example, the deprotection reactivity can be adjusted to a low level by introducing an electron-withdrawing group such as a halogen atom, cyano group, or nitro group to the aromatic group.

[0037] Examples of cations of the sulfonium salt represented by formula (1) include, but are not limited to, those listed below. [ka]

[0038] [ka]

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071] [Chemistry]

[0072] [Chemistry]

[0073] [Chemistry]

[0074] [Chemistry]

[0075] [Chemistry]

[0076] [Chemistry]

[0077] [Chemistry]

[0078] In formula (1), X - is a non-nucleophilic counter ion that is a weaker acid than sulfonic acid. Examples of the non-nucleophilic counter ion include carboxylic acid anion, sulfonamide anion, methide acid anion without a fluorine atom, phenoxide anion, halide anion, carbonate anion, and the like.

[0079] The carboxylic acid anion is preferably represented by the following formula (2)-1. The sulfonamide anion is preferably represented by the following formula (2)-2. The fluorine atom-free methidoic acid anion is preferably represented by the following formula (2)-3. The phenoxide anion is preferably represented by the following formula (2)-4. [ka]

[0080] In formula (2)-1, R 11 R is a C1-C24 hydrocarbyl group which may contain a hydrogen atom, a fluorine 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 formula (3A') described later. 111 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, mercapto groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0081] In formula (2)-2, R 12 R is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. 13 R is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen 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 formula (3A') described later. 111Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, mercapto groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0082] In formula (2)-3, R 14 ~R 16 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms. 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 include those having 1 to 10 carbon atoms. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, mercapto groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0083] In formula (2)-4, R 17k is a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, a C2-C10 alkylcarbonylamino group, a C1-C10 alkylsulfonylamino group, a C1-C10 alkylsulfonyloxy group, a C1-C10 alkyl group, a phenyl group, a C1-C10 alkoxy group, a C1-C10 alkylthio group, a C2-C10 alkoxycarbonyl group, a C1-C10 acyl group, or a C1-C10 acyloxy group, and some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with fluorine atoms. k is an integer from 0 to 5. When k is 2 or greater, each R 17 They may be the same or different from one another.

[0084] Examples of the carboxylic acid anions mentioned above include, but are not limited to, those listed below. [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091]

Chem.

[0092]

Chem.

[0093]

Chem.

[0094]

Chem.

[0095]

Chem.

[0096]

Chem.

[0097]

Chem.

[0098]

Chem.

[0099] Examples of sulfonamide anions include, but are not limited to, those shown below.

Chem.

[0100]

Chem.

[0101]

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[0105]

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[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] Examples of methidate anions that do not contain a fluorine atom include, but are not limited to, those listed below. [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] Examples of the phenoxide anions mentioned above include, but are not limited to, those listed below. [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] One method for synthesizing the sulfonium salt represented by formula (1) is to exchange the weak salt of the aforementioned sulfonium cation with an ammonium salt having a carboxylic acid anion, a sulfonamide anion, a fluorine-free methidoate anion, a phenoxide anion, a halide anion, or a carbonate anion.

[0128] In the resist material of the present invention, the content of the sulfonium salt represented by formula (1) is preferably 0.001 to 100 parts by mass, and more preferably 0.005 to 50 parts by mass, per 100 parts by mass of the base polymer described later, from the viewpoint of sensitivity and acid diffusion suppression effect.

[0129] [Base polymer] The base polymer contained in the resist material of the present invention contains a repeating unit containing an acid-labile group in the case of a positive resist material. As the repeating unit containing an acid-labile group, a repeating unit represented by the following formula (a1) (hereinafter, also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter, also referred to as repeating unit a2) is preferable.

Chemical formula

[0130] In formulas (a1) and (a2), R A is independently a hydrogen atom or a methyl group. X 1 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond and a lactone ring. X 2 is a single bond or an ester bond. X 3 is a single bond, an ether bond or an ester bond. R 21 and R 22 are independently acid-labile groups. R 23 is a fluorine atom, a trifluoromethyl group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 7 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms or a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms. R 24 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and a part of -CH2- of the alkanediyl group may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4. However, 1 ≤ a + b ≤ 5.

[0131] Examples of the monomer that gives repeating unit a1 include, but are not limited to, those shown below. In the following formulas, R A and R 21 are the same as described above.

Chemical formula

[0132] 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 22 This is the same as described above. [ka]

[0133] In equations (a1) and (a2), R 21 and R 22 Examples of acid-unstable groups represented by include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0134] Typically, the acid-unstable groups mentioned above are those represented by the following formulas (AL-1) to (AL-3). [ka] (In the equation, dashed lines represent connections.)

[0135] In equations (AL-1) and (AL-2), R L1 and R L2 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A saturated hydrocarbyl group having 1 to 40 carbon atoms is preferred, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferred.

[0136] In formula (AL-1), c is an integer between 0 and 10, preferably between 1 and 5.

[0137] In formula (AL-2), R L3 and R L4Each of these is independently a hydrogen atom or a C1-C20 hydrocarbyl group, and may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A saturated hydrocarbyl group having C1-C20 is preferred as the hydrocarbyl group. Also, R L2 , R L3 and R L4 Any two of these may bond with each other to form a ring having 3 to 20 carbon atoms, together with the carbon atom to which they are bonded, or with a carbon atom and an oxygen atom. The ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0138] In formula (AL-3), R L5 , R L6 and R L7 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred as the hydrocarbyl group. Also, R L5 , R L6 and R L7 Any two of these may bond with each other to form a ring with 3 to 20 carbon atoms. The ring is preferably a ring with 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0139] The base polymer may contain repeating unit b having a phenolic hydroxyl group as an adhesion group. Examples of monomers that give repeating unit b are, but are not limited to, those listed below. In the following formula, R A This is the same as described above. [ka]

[0140] The 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, or carboxyl groups. Examples of monomers that give repeating units c are, but are not limited to, those listed below. In the following formula, R A This is the same as described above. [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] The base polymer may contain repeating units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Examples of monomers that give repeating units d are, but are not limited to, those listed below. [ka]

[0149] The base polymer may contain repeating units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindan, vinylpyridine, or vinylcarbazole.

[0150] The 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 formula (f1) (hereinafter also referred to as repeating unit f1), the repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and the repeating unit represented by the following 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]

[0151] In formulas (f1) to (f3), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to a single bond, 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, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11This 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 31 This is an aliphatic 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 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxyl group, or a halogen atom.

[0152] In formulas (f1) to (f3), R 31 ~R 38 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently 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 formula (3) described later. 101 ~R 103Examples of hydrocarbyl groups represented by are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- of the hydrocarbyl group 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 (-C(=O)-OC(=O)-), haloalkyl group, etc. 33 and R 34 or R 36 and R 37 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is as follows, as described in the explanation of formula (3) below: 101 and R 102 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.

[0153] In formula (f1), M - This is a non-nucleophilic counterion. Examples of the aforementioned non-nucleophilic counterions include halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonate ions such as triflate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkyl sulfonate ions such as mesylate ions and butanesulfonate ions; imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; and methide ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

[0154] Other examples of the aforementioned non-nucleophilic counterions include a sulfonate ion in which the α-position is substituted with a fluorine atom, represented by the following formula (f1-1), and a sulfonate ion 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 formula (f1-2). [ka]

[0155] In formula (f1-1), R 41 R 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.

[0156] In formula (f1-2), R 42 R is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 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.

[0157] 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 described above. [ka]

[0158] Examples of monomer cations that give repeating units f2 or f3 include those similar to those exemplified as cations of sulfonium salts represented by formula (3) described later.

[0159] 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 described above. [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167] [ka]

[0168] [ka]

[0169] [ka]

[0170] [ka]

[0171] 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 described above. [ka]

[0172] By binding an acid generator to the polymer backbone, acid diffusion can be 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.

[0173] The base polymer for the positive resist material essentially contains the repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0174] On the other hand, the base polymer for the negative resist material does not necessarily require an acid-labile group. Examples of such a base polymer include those containing the repeating unit b and optionally further containing the repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≦ 1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0.2 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0.3 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0175] To synthesize the base polymer, for example, a monomer that provides the aforementioned repeating unit may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0176] 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.

[0177] 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.

[0178] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0179] 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.

[0180] The 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.

[0181] Furthermore, if the molecular weight distribution (Mw / Mn) of the base polymer is broad, low molecular weight and high molecular weight polymers may be present, which may result in the appearance of foreign matter on the pattern or deterioration of the pattern shape after exposure. As the pattern rules become 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 base polymer be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0182] The base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0183] [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.

[0184] As an additive-type acid generator, a compound that generates acid in response to active light or radiation (photoacid generator) is preferred. Any compound that generates acid upon irradiation with high-energy rays can be used as the 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.

[0185] Furthermore, a photoacid generator represented by the following formula (3) can also be suitably used. [ka]

[0186] In formula (3), R 101 ~R 103 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom.

[0187] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0188] R 101 ~R 103 The hydrocarbyl group, represented by , having 1 to 20 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 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-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; C2-C20 alkenyl groups such as vinyl, propenyl, butenyl, and hexenyl; and ethynyl groups. Examples include alkynyl groups with 2 to 20 carbon atoms, such as propynyl and butynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl and norbornenyl groups; aryl groups with 6 to 20 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 20 carbon atoms, such as benzyl and phenethyl groups; and groups obtained by combining these.

[0189] 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.

[0190] Also, R 101 and R 102 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is preferably structured as shown below. [ka] (In the formula, the dashed line represents R 103 (This is a combination of the two.)

[0191] Examples of cations of the sulfonium salt represented by formula (3) include, but are not limited to, those listed below. [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195]

change

[0196]

change

[0197]

change

[0198]

change

[0199]

change

[0200]

change

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209]

change

[0210]

change

[0211]

change

[0212]

change

[0213]

change

[0214]

change

[0215] As the additive-type acid generator or the monomer that gives the repeating unit f2 or f3 mentioned above, cations with an aromatic group used in sulfonium salts represented by formula (1), tertiary ester-type acid-unstable groups, conventional alicyclic or alkyl group-type acid-unstable groups, or acid-unstable groups containing aromatic groups other than those of sulfonium salts represented by formula (1) or acid-unstable groups having triple bonds can also be used.

[0216] In equation (3), Xa - This is an anion selected from the following formulas (3A) to (3D). [ka]

[0217] In formula (3A), R fa R is a C1-C40 hydrocarbyl group which may contain a fluorine 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 formula (3A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0218] The anion represented by formula (3A) is preferably the one represented by formula (3A') below. [ka]

[0219] In 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. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. The hydrocarbyl group is particularly preferred to have 6 to 30 carbon atoms in order to obtain high resolution in fine pattern formation.

[0220] R 111 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 38 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-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, and 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.

[0221] 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 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. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0222] For details on the synthesis of sulfonium salts containing the anion represented by 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. Also, 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 be suitably used.

[0223] The anions represented by formula (3A) include, but are not limited to, those listed below. In the formula below, Ac represents an acetyl group. [ka]

[0224] [ka]

[0225] [ka]

[0226] [ka]

[0227] In formula (3B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine 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 formula (3A'). 111 Examples 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.

[0228] In formula (3C), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine 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 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.

[0229] In formula (3D), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The 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 same formula as those exemplified above include those shown.

[0230] The synthesis of sulfonium salts containing the anion represented by formula (3D) is detailed in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0231] The anions represented by formula (3D) include, but are not limited to, those listed below. [ka]

[0232] [ka]

[0233] 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.

[0234] As a photoacid generator, one represented by the following formula (4) can also be suitably used. [ka]

[0235] In 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 formula (3). 101 and R 102Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0236] 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 alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 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 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 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.

[0237] R 203 The 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 the hydrocarbylene 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 hydrocarbylene 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 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. The heteroatom is preferably an oxygen atom.

[0238] In formula (4), L A This is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The 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.

[0239] In 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.

[0240] In equation (4), d is an integer between 0 and 3.

[0241] As the photoacid generator represented by formula (4), the one represented by the following formula (4') is preferred. [ka]

[0242] In 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 independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen 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 formula (3A'). 111Examples 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.

[0243] Examples of photoacid generators represented by formula (4) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0244] Among the photoacid generators, those containing an anion represented by 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.

[0245] As the photoacid generator, a sulfonium salt or iodonium salt 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 formulas (5-1) or (5-2). [ka]

[0246] In equations (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.

[0247] In equations (5-1) and (5-2), X BI p' and / or q' are iodine atoms or bromine atoms, and when p' and / or q' are 2 or more, they may be the same or different from each other.

[0248] In equations (5-1) and (5-2), L 1This 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.

[0249] In equations (5-1) and (5-2), L 2 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, or a nitrogen atom.

[0250] In equations (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, 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 aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy 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.

[0251] 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.

[0252] In equations (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.

[0253] In equations (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 hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formula (3), R 101 ~R 103 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, carboxyl group, halogen atom, cyano group, nitro group, mercapto group, sultone ring, sulfo group, or sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, ester bond, carbonyl group, amide bond, carbonate bond, or sulfonic acid ester bond. 402 and R 403 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is R as described in the explanation of formula (3). 101 and R 102 Examples of rings that can be formed when these elements combine with each other, along with the sulfur atom to which they are bonded, are similar to those exemplified above.

[0254] Examples of cations for sulfonium salts represented by formula (5-1) are the same as those exemplified for sulfonium salts represented by formula (3). Examples of cations for iodonium salts represented by formula (5-2) are listed below, but are not limited to these. [ka]

[0255] [ka]

[0256] The anions of the onium salt represented by 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.

change

[0257]

change

[0258]

change

[0259]

change

[0260]

change

[0261]

change

[0262]

change

[0263]

change

[0264]

change

[0265]

change

[0266]

change

[0267]

change

[0268]

change

[0269]

change

[0270]

change

[0271]

change

[0272]

change

[0273]

change

[0274]

change

[0275]

change

[0276]

change

[0277] [ka]

[0278] [ka]

[0279] The content of the additive-type acid generator 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 described later. The resist material of the present invention can function as a chemically amplified resist material by the base polymer containing any of the repeating units f1 to f3 and / or by containing the additive-type acid generator.

[0280] [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, 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, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and di Examples include ethers such as ethylene glycol dimethyl ether, 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, propylene glycol monotert-butyl ether acetate, esters such as methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, propyl 2-hydroxyisobutyrate, and butyl 2-hydroxyisobutyrate, and lactones such as γ-butyrolactone.

[0281] In the resist material of the present invention, the content of the 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 organic solvent may be used alone or as a mixture of two or more types.

[0282] [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 salts represented by formula (1) (hereinafter referred to as "other quenchers"), water-repellency enhancers, acetylene alcohols, and the like.

[0283] 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 a 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.

[0284] When the resist material of the present invention is of the positive type, by incorporating a dissolution inhibitor, the difference in dissolution rate between the exposed and unexposed areas can be further increased, thereby further improving the resolution. Examples of the 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, for example, those described in paragraphs

[0155] to

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

[0285] When the resist material of the present invention is of the positive type and contains the 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 dissolution inhibitor may be used alone or in combination of two or more types.

[0286] On the other hand, if the resist material of the present invention is negative type, a negative type 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 or urea compounds, isocyanate compounds, azide compounds, and 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.

[0287] Examples of the epoxy compound include tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0288] Examples of the 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.

[0289] Examples of the 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.

[0290] Examples of glycoluryl compounds 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. Examples of urea compounds include tetramethylolurea, tetramethoxymethylurea, compounds in which 1 to 4 methylol groups of tetramethylolurea are methoxymethylated or mixtures thereof, tetramethoxyethylurea, and the like.

[0291] Examples of the isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0292] Examples of the aforementioned azide compounds include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0293] Examples of compounds containing the aforementioned 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.

[0294] If the resist material of the present invention is of the negative type and contains a crosslinking agent, the content of the crosslinking agent 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 crosslinking agent may be used alone or in combination of two or more types.

[0295] Examples of other quenchers 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.

[0296] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids or fluorinated alkoxides whose α-position is not fluorinated, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imido acids, or methidic acids whose α-position is fluorinated are necessary to deprotect 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 or fluorinated alcohols whose α-position is not fluorinated. Since sulfonic acids, carboxylic acids, and fluorinated alcohols whose α-position is not fluorinated do not undergo deprotection reactions, they function as quenchers.

[0297] 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 quenchers may be used individually or in combination of two or more types.

[0298] The 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 and polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, as exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103. The 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 residues mentioned 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 the evaporation of acid in the PEB and preventing poor hole pattern opening after development. If the resist material of the present invention contains a water-repellency improving agent, the content thereof 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 water-repellency improving agent may be used alone or in combination of two or more types.

[0299] Examples of the aforementioned acetylene alcohols include those described in paragraphs

[0179] to

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

[0300] The resist material of the present invention can be prepared by thoroughly mixing the above-mentioned components, adjusting the sensitivity and film thickness to a predetermined range, and then filtering the resulting solution. The filtration step is important for reducing defects in the resist pattern after development. The diameter of the membrane for filtration is preferably 1 μm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. The smaller the diameter, the more effectively defects in fine patterns can be suppressed. Examples of membrane materials include tetrafluoroethylene, polyethylene, polypropylene, nylon, polyurethane, polycarbonate, polyimide, polyamideimide, and polysulfone. Membranes with modified surfaces of tetrafluoroethylene, polyethylene, polypropylene, etc., to enhance adsorption capacity can also be used. Since tetrafluoroethylene, polyethylene, and polypropylene are nonpolar, they do not have the ability to adsorb gels or metal ions due to polarity, unlike membranes of nylon, polyurethane, polycarbonate, and polyimide. However, surface modification with polar functional groups can enhance the adsorption capacity of gels and metal ions. In particular, by surface modifying polyethylene or polypropylene membranes, which can form membranes with smaller diameters, it is possible to reduce not only fine particles but also polar particles and metal ions. You may also use films made of different materials or films with different pore sizes.

[0301] A membrane with ion exchange capabilities can also be used. In the case of an ion exchange membrane that adsorbs cations, metal impurities can be reduced by adsorbing metal ions.

[0302] Multiple filters can be connected when performing filtration. The membrane types and diameters of the multiple filters may be the same or different. Filtration may be performed in piping connecting multiple containers, or a single container may have an outlet and inlet, and piping may be connected to perform circulating filtration. The filters used for filtration may be connected in series piping or in parallel piping.

[0303] [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 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.

[0304] First, the resist material of the present invention is used as a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coatings, etc.) or as a substrate for mask circuit manufacturing (Cr, CrO, CrON, CrN, MoSi2, SiO 2、 A MoSi2 multilayer film (Ta, TaN, TaCN, Ru, Nb, Mo, Mn, Co, Ni, or alloys thereof, etc.) is coated with a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating to a coating thickness of 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.

[0305] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far-ultraviolet rays, EB rays, EUV rays 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 rays, 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, and is especially suitable for fine patterning using EB or EUV.

[0306] 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.

[0307] 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 (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH), 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.

[0308] 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.

[0309] 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.

[0310] The 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.

[0311] Examples of the 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.

[0312] Examples of C6-C12 alkanes include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of C6-C12 alkenes include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of C6-C12 alkynes include hexine, heptine, and octin.

[0313] Examples of the aforementioned aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0314] Rinsing can reduce the occurrence of resist pattern deformation and defects. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0315] 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]

[0316] 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.

[0317] The structures of quenchers Q-1 to Q-19 used in the resist material are shown below. Q-1 to Q-19 were synthesized by ion exchange between an ammonium salt that gives the anion shown below and a sulfonium chloride that gives the cation shown below. [ka]

[0318] [ka]

[0319] [ka]

[0320] [Synthesis Example] Synthesis of base polymers (P-1 to P-7) Each monomer was combined and copolymerized in THF, a solvent, then added to methanol. The precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (P-1 to P-7) 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]

[0321] [ka]

[0322] [ka]

[0323] [Examples 1-25, Comparative Examples 1 and 2] Preparation and evaluation of resist materials (1) Preparation of resist material A resist material was prepared by dissolving each component in a solvent containing 100 ppm of Polyfox PF-636 manufactured by Omnova as a surfactant, according to the compositions shown in Tables 1 and 2, and then filtering the solution through a 0.2 μm filter.

[0324] In Tables 1 and 2, the components are as follows: • Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (Ethyl Lactate) DAA (Diacetone Alcohol)

[0325] • Acid generators: PAG-1 to PAG-6 [ka]

[0326] • Comparative quenchers: cQ-1, cQ-2 [ka]

[0327] (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 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. A resist film with a thickness of 50 nm was fabricated by pre-baking at 105°C for 60 seconds using a hot plate. The resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimension of 40 nm pitch, +20% bias hole pattern mask), and PEB was performed on a hot plate at the temperatures listed in Tables 1 and 2 for 60 seconds. Development was then performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to form a hole pattern with dimensions of 20 nm. Using a Hitachi High-Technologies Corporation length-measuring SEM (CG6300), the exposure amount when a hole with a dimension of 20 nm was formed was measured and defined as the sensitivity. The dimensions of 50 holes at this point were also measured, and the CDU was defined as three times the standard deviation (σ) calculated from these results (3σ). The results are shown in Tables 1 and 2.

[0328] [Table 1]

[0329] [Table 2]

[0330] The results shown in Tables 1 and 2 indicate that the resist material of the present invention, which contains a sulfonium salt of a weak acid having a tertiary ester-type acid-unstable group with a triple bond as a cation, exhibits good CDU (Chemical Duplication).

Claims

1. A resist material comprising a quencher containing a sulfonium salt represented by the following formula (1), and an acid generator that generates a strong acid. 【Chemistry 1】 (In the formula, p is 0 or 1, q is an integer from 0 to 4, r is 1, and s is 1.) R 1 These are single bonds, ether bonds, thioether bonds, or ester bonds. R 2 This is a single bond or an alkanediyl group having 1 to 20 carbon atoms, and the alkanediyl group may have a fluorine atom or a hydroxyl group. R 3 and R 4 Each of these is independently a saturated hydrocarbyl group having 1 to 12 carbon atoms, and the saturated hydrocarbyl group may contain an oxygen atom or a sulfur atom. Also, R 3 and R 4 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 5 This is a hydrogen atom, a saturated hydrocarbyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms, and the saturated hydrocarbyl group and aryl group may have at least one selected from a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an amino group, a trifluoromethyl group, a trifluoromethoxy group, and a trifluoromethylthio group. R 6 This is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, which may contain at least one selected from a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxyl group, an amino group, and an ether bond. R 7 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain heteroatoms. When s = 1, the two Rs 7 may be the same as or different from each other, and may combine with each other to form a ring together with the sulfur atom to which they are attached. X - It is a non-nucleophilic counterion that is a weaker acid than sulfonic acid.

2. X - The resist material according to claim 1, wherein the non-nucleophilic counterion represented by is a carboxylic acid anion, a sulfonamide anion, a fluorine atom-free methidoate anion, a phenoxide anion, a halide anion, or a carbonate anion.

3. The resist material according to claim 2, wherein the carboxylic acid anion is represented by the following formula (2)-1, the sulfonamide anion is represented by the following formula (2)-2, the fluorine atom-free methidoic acid anion is represented by the following formula (2)-3, and the phenoxide anion is represented by the following formula (2)-4. 【Chemistry 2】 (In the formula, R 11 This is a hydrocarbyl group having 1 to 24 carbon atoms, which may contain a hydrogen atom, a fluorine atom, or a heteroatom. R 12 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. R 13 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. R 14 ~R 16 Each of these is independently a C1-C10 hydrocarbyl group which may contain heteroatoms other than fluorine atoms. R 17 These are halogen atoms, hydroxyl groups, cyano groups, nitro groups, amino groups, C2-C10 alkylcarbonylamino groups, C1-C10 alkylsulfonylamino groups, C1-C10 alkylsulfonyloxy groups, C1-C10 alkyl groups, phenyl groups, C1-C10 alkoxy groups, C1-C10 alkylthio groups, C2-C10 alkoxycarbonyl groups, C1-C10 acyl groups, or C1-C10 acyloxy groups, and some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with fluorine atoms. k is an integer between 0 and 5.

4. The resist material according to claim 1, wherein the strong acid is a sulfonic acid, a fluorinated imido acid, or a fluorinated methido acid.

5. Furthermore, the resist material according to claim 1, further comprising an organic solvent.

6. Furthermore, the resist material according to claim 1, further comprising a base polymer.

7. The resist material according to claim 6, wherein the base polymer comprises a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2). 【Transformation 3】 (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. X 1 This is a linking group having 1 to 12 carbon atoms, containing at least one of a single bond, a phenylene group or a naphthylene group, or an ester bond, an ether bond, and a lactone ring. X 2 These are single bonds or ester bonds. X 3 These are single bonds, ether bonds, or ester bonds. R 21 and R 22 These are, independently, acid-unstable groups. R 23 These are a fluorine atom, a trifluoromethyl group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 7 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms, or a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms. R 24 This is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the -CH of the alkanediyl group 2 - may be partially substituted with an ether bond or an ester bond. a is either 1 or 2. b is an integer between 0 and 4, where 1 ≤ a + b ≤ 5.

8. The resist material according to claim 7, which is a chemically amplified positive-type resist material.

9. The resist material according to claim 6, wherein the base polymer comprises at least one selected from repeating units represented by the following formulas (f1) to (f3). 【Chemistry 4】 (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. Z 1 This includes single bonds, aliphatic hydrocarbylene groups having 1 to 6 carbon atoms, phenylene groups, naphthylene groups, or groups 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 - is Z 11 This 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 hydroxyl group. Z 2 These are single bonds or ester bonds. Z 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 This is an aliphatic 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 This is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and -O-Z. 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 - is Z 51 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxyl group, or a halogen atom. R 31 ~R 38 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 33 and R 34 or R 36 and R 37 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. M - (It is a non-nucleophilic counterion.)

10. Furthermore, the resist material according to claim 1, further comprising a surfactant.

11. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist material described in claim 1; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

12. The pattern formation method according to claim 11, wherein 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.

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