Resist material and pattern forming method

Abstract

To provide a resist material which exhibits high sensitivity and improved LWR and CDU regardless of whether it is positive or negative, and a pattern forming method using the same.SOLUTION: The resist material contains a base polymer and a quencher. The quencher contains a salt compound obtained from: a nitrogen atom-containing compound in which an aromatic ring substituted with an iodine atom is bonded to a nitrogen atom via a C1-20 hydrocarbon group optionally having at least one selected from an ester bond and an ether bond; and one or more selected from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, and a fluorinated imide compound.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. In particular, the expansion of the logic memory market due to the spread of smartphones is driving this miniaturization. Cutting-edge miniaturization technologies include the mass production of 7nm node devices using double patterning with ArF immersion lithography, and the mass production of 5nm node devices using extreme ultraviolet (EUV) lithography.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the optical contrast decreases. This decrease in optical contrast causes a decrease in the resolution of hole and trench patterns and a decrease in focus margin in positive resist films. To prevent this decrease in resist pattern resolution, attempts are being made to improve the dissolution contrast of resist films.

[0004] For chemically amplified positive resist materials, which contain an acid generator and generate acid upon irradiation with light or an electron beam (EB), causing an acid-induced deprotection reaction, and for chemically amplified negative resist materials, which cause an acid-induced polarity change reaction or crosslinking reaction, the addition of a quencher to control the diffusion of acid into unexposed areas and improve contrast has been very effective. For this reason, many amine quenchers have been proposed (Patent Documents 1 to 3).

[0005] The acid-labile groups used in (meth)acrylate polymers for ArF resist materials undergo deprotection using a photoacid generator that generates sulfonic acid substituted with a fluorine atom at the α-position, but not with an acid generator that generates sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position. When a sulfonium salt or iodonium salt that generates sulfonic acid substituted with a fluorine atom at the α-position is mixed with a sulfonium salt or iodonium salt that generates sulfonic acid not substituted with a fluorine atom at the α-position, the sulfonium salt or iodonium salt that generates sulfonic acid not substituted with a fluorine atom at the α-position undergoes ion exchange with the sulfonic acid not substituted with a fluorine atom at the α-position. The sulfonic acid substituted with a fluorine atom at the α-position generated by light reverts to the sulfonium salt or iodonium salt through ion exchange, and the sulfonium salt or iodonium salt of the sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position functions as a quencher. A resist material has been proposed that uses a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher (Patent Document 4).

[0006] Sulfonium salt-type quenchers and iodonium salt-type quenchers are photodegradable, similar to photoacid generators. In other words, the amount of quencher decreases in the exposed area. Because acid is generated in the exposed area, reducing the amount of quencher increases the relative acid concentration, thereby improving contrast. However, acid diffusion in the exposed area cannot be suppressed, making acid diffusion control difficult.

[0007] Resist materials containing aniline compounds substituted with iodine atoms have been proposed (Patent Documents 5 and 6). Aniline compounds have the problem of low acid diffusion performance due to their low basicity and poor acid capture ability. There is a need for the development of quenchers that have excellent acid diffusion control ability, high absorption, and high sensitization effects.

[0008] The number of photons absorbed in a resist film during EUV exposure is said to be 1 / 14 of the number of photons during ArF exposure, and it is known that dimensional variations occur due to photon variations, i.e., shot noise (Non-Patent Document 1). Furthermore, it is believed that dimensional variations occur not only due to photon variations but also due to variations in the components within the resist film, and the development of resist materials with uniform components has been proposed (Non-Patent Document 2). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-194776 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-226470 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-363148 [Patent Document 4] International Publication No. 2008 / 066011 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-83957 [Patent Document 6] Japanese Patent Application Publication No. 2018-97356 [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 3331 p531 (1998) [Non-patent document 2] SPIE Vol. 9776 p97760V-1 (2016) Summary of the Invention [Problem to be solved by the invention]

[0011] In resist materials, there is a need for the development of quenchers that can improve line edge roughness (LWR) and hole dimension uniformity (CDU), as well as improve sensitivity.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist material that has high sensitivity and improved LWR and CDU, whether it is a positive or negative resist material, and a pattern formation method using the same. [Means for solving the problem]

[0013] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that by using, as a quencher, a salt compound obtained from a nitrogen-atom-containing compound having an aromatic ring substituted with a specific iodine atom and one or more compounds selected from the group consisting of a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, and a fluorinated imide compound, it is possible to obtain a resist material that has improved LWR and CDU, high contrast, excellent resolution, and a wide process margin, and have completed the present invention.

[0014] That is, the present invention provides the following resist material and pattern forming method. 1. A resist material comprising a base polymer and a quencher, The resist material according to the present invention, wherein the quencher comprises a nitrogen-atom-containing compound in which an aromatic ring substituted with an iodine atom is bonded to a nitrogen atom via a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group optionally containing at least one bond selected from an ester bond and an ether bond, and at least one compound selected from the group consisting of a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, and a fluorinated imide compound. 2. The resist material of 1, wherein the salt compound is represented by the following formula (A): [ka] (In the formula, m and n are integers satisfying the conditions 1≦m≦5, 0≦n≦4, and 1≦m+n≦5. k 1 is an integer between 1 and 3. 2 is 1 or 2. X 1 is the carbon number 1 to 20 (k2 It is a monovalent hydrocarbon group, and may contain at least one bond selected from an ester bond and an ether bond. R 1 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B or -N(R 1A )-C(=O)-OR 1B R 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. R 2 is a hydrogen atom, a nitro group, or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain at least one group selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a halogen atom, and an amino group. 1 When is 1 or 2, two R 2 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom, or a nitrogen atom. 2 and X 1 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. R 3 and R 4 are each independently a hydrocarbyl group having 1 to 16 carbon atoms, a fluorinated hydrocarbyl group having 1 to 16 carbon atoms, a hydrocarbyloxy group having 1 to 16 carbon atoms, or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, but R 3 and R 4At least one of the groups is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, some or all of whose hydrogen atoms may be substituted with at least one selected from a cyano group, a nitro group, a hydroxy group, and a halogen atom other than a fluorine atom, and some of whose -CH2- groups may be substituted with at least one selected from an ether bond, an ester bond, and a thioether bond. X 2 is -C(H)= or -N=. 3. The resist material of 1 or 2, further comprising an acid generator that generates a sulfonic acid, an imide acid, or a methide acid. 4. The resist material of any one of 1 to 3, further comprising an organic solvent. 5. The resist material of any one of 1 to 4, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 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 14is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of the -CH2- groups may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 6. The resist material of 5, which is a chemically amplified positive resist material. 7. The resist material of any one of 1 to 4, wherein the base polymer does not contain an acid labile group. 8. The resist material of 7, which is a chemically amplified negative resist material. 9. The resist material according to any one of 1 to 8, further comprising a surfactant. 10. The resist material of any one of 1 to 9, wherein the base polymer further contains a repeating unit represented by any one of the following formulas (f1) to (f3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents 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 -It is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)-. Z 21 is a saturated hydrocarbylene group having 1 to 12 carbon atoms, which may contain a carbonyl group, an ester bond or an ether bond. Z 3represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31 -, -C(=O)-OZ 31 - or -C(=O)-NH-Z 31 -It is. Z 31 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. M - is a non-nucleophilic counterion. 11. A pattern forming method comprising the steps of forming a resist film on a substrate using a resist material according to any one of 1 to 10, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer. 12. The pattern formation method according to 11, wherein the high-energy radiation is ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, EB, or EUV with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0015] The salt compound represented by formula (A) has high EUV absorption due to the presence of iodine atoms, resulting in a sensitizing effect. Furthermore, the large atomic weight of the iodine atoms also effectively suppresses acid diffusion. Furthermore, since it is not photosensitive and does not decompose in exposed areas, it has high acid diffusion control ability in exposed areas and can also suppress pattern film loss using alkaline developers. Quenchers composed of salts containing anions derived from fluorinated 1,3-diketone compounds, fluorinated β-ketoester compounds, or fluorinated imide compounds disperse uniformly within resist films due to the repulsive effect of fluorine atoms, enabling the construction of resist materials with high sensitivity, improved LWR, and improved CDU. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Resist materials] The resist material of the present invention comprises a base polymer and a quencher. The quencher comprises a salt compound (hereinafter also referred to as salt compound A) obtained from a nitrogen-atom-containing compound in which an iodine-substituted aromatic ring is bonded to a nitrogen atom via a hydrocarbon group having 1 to 20 carbon atoms, which may contain at least one bond selected from an ester bond and an ether bond, and one or more compounds selected from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, and a fluorinated imide compound.

[0017] [Salt Compound A] The salt compound A is preferably represented by the following formula (A). [ka]

[0018] In formula (A), m and n are integers satisfying the conditions 1≦m≦5, 0≦n≦4, and 1≦m+n≦5. 1 is an integer between 1 and 3. 2 is 1 or 2.

[0019] In formula (A), X 1 is the carbon number 1 to 20 (k2 It is a (+1)-valent hydrocarbon group, which may contain at least one bond selected from an ester bond and an ether bond. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include hydrocarbylene groups having 1 to 20 carbon atoms and trivalent groups obtained by further eliminating one hydrogen atom from the hydrocarbylene group. Examples of the hydrocarbylene group include methylene, ethylene, propane-1,2-diyl, propane-1,3-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, and undecane-1,11-diyl. alkanediyl groups such as dodecane-1,12-diyl group; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms such as vinylene group and propene-1,3-diyl group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group; and groups obtained by combining these.

[0020] In formula (A), R 1 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B or -N(R 1A )-C(=O)-OR 1B R 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms.

[0021] The saturated hydrocarbyl group having 1 to 6 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclobutyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, etc. Furthermore, examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms and the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms include the same as the specific examples of the saturated hydrocarbyl group described above.

[0022] The unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a vinyl group, a 1-propenyl group, a 2-propenyl group, a butenyl group, a hexenyl group, and a cyclohexenyl group.

[0023] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a 1-naphthyl group, a 2-naphthyl group, etc. Examples of the aralkyl group having 7 to 13 carbon atoms include a benzyl group, a phenethyl group, etc.

[0024] Of these, R 1 Examples of the alkyl group include a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, a saturated hydrocarbyl group having 1 to 3 carbon atoms, a saturated hydrocarbyloxy group having 1 to 3 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 4 carbon atoms, and -N(R 1A )-C(=O)-R 1B or -N(R 1A )-C(=O)-OR 1B When n is 2 or more, each R 1 may be the same or different.

[0025] In formula (A), R 2is a hydrogen atom, a nitro group, or a hydrocarbyl group having 1 to 20 carbon atoms. The hydrocarbyl group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, 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 icosyl groups; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl groups; and cyclohexenyl and norbornenyl groups. alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, and butynyl; aryl groups having 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; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenethyl; and groups obtained by combining these, such as 2-cyclohexylethynyl and 2-phenylethynyl. The hydrocarbyl group may contain at least one selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a halogen atom, and an amino group.

[0026] k 1 When is 1 or 2, each R 2 may be the same or different. 1 When is 1 or 2, two R2 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom, or a nitrogen atom. 2 and X 1 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom.

[0027] Examples of the cation derived from the nitrogen atom-containing compound of salt compound A include, but are not limited to, the following: [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035]

change

[0036]

change

[0037]

change

[0038]

change

[0039]

change

[0040]

change

[0041]

change

[0042]

change

[0043]

change

[0044]

change

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] In formula (A), R 3 and R 4 are each independently a hydrocarbyl group having 1 to 16 carbon atoms, a fluorinated hydrocarbyl group having 1 to 16 carbon atoms, a hydrocarbyloxy group having 1 to 16 carbon atoms, or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, but R 3 and R 4 At least one of the groups is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, some or all of whose hydrogen atoms may be substituted with at least one selected from a cyano group, a nitro group, a hydroxy group, and a halogen atom other than a fluorine atom, and some of whose -CH2- groups may be substituted with at least one selected from an ether bond, an ester bond, and a thioether bond.

[0050] R 3 and R 4The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 16 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl groups. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, norbornyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, cyclohexylethyl, methylcyclopropyl, methylcyclobutyl, methylcyclopentyl, methylcyclohexyl, ethylcyclopropyl, ethyl Cyclic saturated hydrocarbyl groups having 3 to 16 carbon atoms, such as ethylcyclobutyl, ethylcyclopentyl, and ethylcyclohexyl; alkenyl groups having 2 to 16 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, pentenyl, hexenyl, heptenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, and hexadecenyl; ethynyl, propynyl, butynyl, and pentynyl alkynyl groups having 2 to 16 carbon atoms, such as a hexynyl group, a heptynyl group, an octynyl group, a nonynyl group, a decynyl group, an undecynyl group, a dodecynyl group, a tridecynyl group, a tetradecynyl group, a pentadecynyl group, or a hexadecinyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 16 carbon atoms, such as a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclohexenyl group, an ethylcyclopentenyl group, an ethylcyclohexenyl group, or a norbornenyl group;Examples of such aryl groups include aryl groups having 6 to 16 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; aralkyl groups having 7 to 16 carbon atoms, such as benzyl, phenethyl, phenylpropyl, phenylbutyl, 1-naphthylmethyl, 2-naphthylmethyl, 9-fluorenylmethyl, 1-naphthylethyl, 2-naphthylethyl, and 9-fluorenylethyl; and groups obtained by combining these groups.

[0051] R 3 and R 4 The fluorinated hydrocarbyl group represented by the formula (I) and the fluorinated hydrocarbyl portion of the fluorinated hydrocarbyloxy group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 3 and R 4and groups in which at least one hydrogen atom of the groups exemplified as the hydrocarbyl moiety of the hydrocarbyloxy group is substituted with a fluorine atom, such as a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 1,1,1,3,3,3-hexafluoro-2-propyl group, a 1,1,2,2,3,3,3-heptafluoropropyl group, a 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, a 2-fluorophenyl group, a 3-fluorophenyl group, a 4-fluorophenyl group, a 5-fluorophenyl group, a 6-fluorophenyl group, a 7-fluorophenyl group, a 8-fluorophenyl group, a 9-fluorophenyl group, a 10-fluorophenyl group, a 11-fluorophenyl group, a 12-fluorophenyl group, a 13-fluorophenyl group, a 14-fluorophenyl group, a 15-fluorophenyl group, a 16-fluorophenyl group, a 17-fluorophenyl group, a 18-fluorophenyl group, a 19-fluorophenyl group, a 20-fluorophenyl group, a 21-fluorophenyl group, a 22-fluorophenyl group, a 23-fluorophenyl group, a 24-fluorophenyl group, a 25-fluorophenyl group, a 26-fluorophenyl group, a 27-fluorophenyl group, a 28-fluorophenyl group, a 29-fluorophenyl group, a 30-fluorophenyl group, a 31-fluorophenyl group, a 32-fluorophenyl group, a 33-fluorophenyl group, a 34-fluorophenyl group, a 35-fluorophenyl group, a 36-fluorophenyl group, a 37-fluorophenyl group, a 38-fluorophenyl group, a 39-fluorophenyl group, a 40-fluorophenyl group, a 41- Examples of such groups include a fluorophenyl group, a 2,4-difluorophenyl group, a 2,3-difluorophenyl group, a 3,4-difluorophenyl group, a 3,5-difluorophenyl group, a 2,4,5-trifluorophenyl group, a 2,3,4-trifluorophenyl group, a 2,3,4,5-tetrafluorophenyl group, a 2,3,5,6-tetrafluorophenyl group, a 2,3,4,5,6-pentafluorophenyl group, a pentafluoromethylphenyl group, a 2-trifluoromethylphenyl group, a 3-trifluoromethylphenyl group, a 4-trifluoromethylphenyl group, and a 2,4,5-trifluorophenyl group.

[0052] In formula (A), X 2 is -C(H)= or -N=.

[0053] Examples of anions derived from the fluorinated 1,3-diketone compound, fluorinated β-ketoester compound, or fluorinated imide compound of salt compound A include, but are not limited to, those shown below. [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] Salt compound A can be synthesized, for example, by neutralizing a nitrogen-containing compound in which an iodine-substituted aromatic ring is bonded to a nitrogen atom via a hydrocarbon group having 1 to 20 carbon atoms, which may contain at least one bond selected from an ester bond and an ether bond, with a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound. Furthermore, when preparing a resist material, the nitrogen-containing compound and the fluorinated 1,3-diketone compound, fluorinated β-ketoester compound, or fluorinated imide compound may be added together with other components and neutralized, thereby incorporating salt compound A into the resist material.

[0059] Salt Compound A functions as a quencher with a sensitizing effect in resist materials. Conventional quenchers reduce sensitivity by controlling acid diffusion, resulting in poor LWR and CDU. However, Salt Compound A's amino group and large iodine atom have an acid diffusion-controlling effect, and because iodine atoms have high EUV absorption, this sensitizing effect also improves sensitivity. Furthermore, the repulsive effect of the fluorinated 1,3-diketone compound, fluorinated β-ketoester compound, and fluorinated imide compound prevents quencher aggregation, resulting in uniform dispersion of the quencher. This results in uniform acid diffusion distances on the nanometer order, improving CDU and LWR.

[0060] In the resist material of the present invention, the content of salt compound A is preferably 0.001 to 50 parts by mass, more preferably 0.01 to 40 parts by mass, per 100 parts by mass of the base polymer described below, from the viewpoints of sensitivity and acid diffusion suppression effect.

[0061] Since salt compound A is not photosensitive, it does not decompose upon exposure to light, and can suppress the diffusion of acid in the exposed area.

[0062] [Base polymer] In the case of a positive resist material, the base polymer contained in the resist material of the present invention contains a repeating unit containing an acid labile group. The repeating unit containing an acid labile group is preferably 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). [ka]

[0063] In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. 2 is a single bond or an ester bond. 3 is a single bond, an ether bond, or an ester bond. 11 and R 12 are each independently an acid labile group. 13 R 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. 14is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of the -CH2- groups may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer of 0 to 4, provided that 1≦a+b≦5.

[0064] Examples of monomers that provide the repeating unit a1 include, but are not limited to, the following: A and R 11 is the same as above. [ka]

[0065] [ka]

[0066] Examples of the monomer that provides the repeating unit a2 include, but are not limited to, the following: A and R 12 is the same as above. [ka]

[0067] In formulas (a1) and (a2), R 11 and R 12 Examples of the acid labile group represented by the formula (I) include those described in JP-A Nos. 2013-80033 and 2013-83821.

[0068] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0069] In formulas (AL-1) and (AL-2), R L1 and RL2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 40 carbon atoms, more preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms.

[0070] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferred.

[0071] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. In addition, R L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0072] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. In addition, R L5 , R L6 and R L7Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0073] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of monomers that provide the repeating unit b include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0074] The base polymer may contain a repeating unit c containing, as another adhesive group, a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonate ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group. Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] The base polymer may contain repeating units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Monomers that provide repeating units d include, but are not limited to, the following: [ka]

[0085] The base polymer may include repeat units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine, or vinylcarbazole.

[0086] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). The repeating units f1 to f3 may be used alone or in combination of two or more. [ka]

[0087] In formulas (f1) to (f3), R A are each independently a hydrogen atom or a methyl group. 1 represents 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 -It is. Z 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)-. Z 21 is a saturated hydrocarbylene group having 1 to 12 carbon atoms, which may contain a carbonyl group, an ester bond, or an ether bond. 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31 -, -C(=O)-OZ 31 - or -C(=O)-NH-Z 31 -It is. Z 31is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 11 and Z 31 The aliphatic hydrocarbylene group represented by Z may be saturated or unsaturated, and may be linear, branched, or cyclic. 21 The saturated hydrocarbylene group represented by the formula (I) may be linear, branched or cyclic.

[0088] In formulas (f1) to (f3), R 21 ~R 28 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in the formulae (1-1) and (1-2) described below. 101 ~R 105 Examples include the same as those exemplified in the description of 1. In addition, 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, a sulfur atom, a nitrogen atom or a 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, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0089] Also, R 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is the same as that described in the description of formula (1-1) below, where R 101 and R 102and the sulfur atom to which they are bonded to form a ring, the same rings as those exemplified above can be mentioned.

[0090] In formula (f2), R HF is a hydrogen atom or a trifluoromethyl group.

[0091] In formula (f1), M - is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0092] Other examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (f1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (f1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0093] In formula (f1-1), R 31is 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. Specific examples thereof include R in formula (1A') described below. 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0094] In formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbyl carbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbyl carbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A') described below. 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0095] Examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, the following: A is the same as above. [ka]

[0096] Examples of the cation of the monomer that gives the repeating unit f2 or f3 include the same cations as those exemplified as the cation of the sulfonium salt represented by formula (1-1) described later.

[0097] Examples of the anion of the monomer that gives the repeating unit f2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0098] [ka]

[0099] Examples of the anion of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. A is the same as above. [ka]

[0100] [ka]

[0101] By bonding the acid generator to the polymer main chain, acid diffusion is reduced, preventing a decrease in resolution due to blurring of the acid diffusion. Furthermore, uniform dispersion of the acid generator improves LWR and CDU. When using a base polymer containing the repeating unit f (i.e., a polymer-bound acid generator), the addition of the additive acid generator described below can be omitted.

[0102] The base polymer for the positive resist material essentially contains a 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.

[0103] 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.

[0104] To synthesize the base polymer, for example, monomers providing the above-described repeating units may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0105] Examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of 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, and more preferably 5 to 20 hours.

[0106] When a monomer containing a hydroxy group is copolymerized, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxyethoxy group, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0107] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0108] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. 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.

[0109] The base polymer preferably has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of 1,000 to 500,000, more preferably 2,000 to 30,000. When the Mw is within this range, the resist film has good heat resistance and solubility in an alkaline developer.

[0110] Furthermore, if the base polymer has a broad molecular weight distribution (Mw / Mn), the presence of low-molecular-weight and high-molecular-weight polymers may result in the appearance of foreign matter on the pattern after exposure, or the pattern shape may be deteriorated. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater. Therefore, in order to obtain a resist material that is suitable for use with fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer has a narrow distribution of 1.0 to 2.0, particularly 1.0 to 1.5.

[0111] The base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0112] [Acid generator] The resist material of the present invention may contain an acid generator (hereinafter also referred to as an additive acid generator) that generates a strong acid. In this context, the term "strong acid" refers to a compound having sufficient acidity to cause a deprotection reaction of acid-labile groups in the base polymer in the case of a chemically amplified positive resist material, and to a compound having sufficient acidity to cause an acid-induced polarity change reaction or crosslinking reaction in the case of a chemically amplified negative resist material. By including such an acid generator, salt compound A functions as a quencher, allowing the resist material of the present invention to function as either a chemically amplified positive resist material or a chemically amplified negative resist material.

[0113] Examples of the acid generator include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon exposure to high-energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0114] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) or an iodonium salt represented by the following formula (1-2) can also be suitably used. [ka]

[0115] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0116] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0117] R 101 ~R 105The hydrocarbyl group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, 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 icosyl groups; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl groups; and ethynyl groups. alkynyl groups having 2 to 20 carbon atoms such as a propynyl group or a butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as a cyclohexenyl group or a norbornenyl group; aryl groups having 6 to 20 carbon atoms such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group or a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as a benzyl group or a phenethyl group; and groups obtained by combining these.

[0118] 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, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0119] Also, R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring preferably has the following structure: [ka] (In the formula, the dashed line indicates R 103 )

[0120] Examples of the cation of the sulfonium salt represented by formula (1-1) include, but are not limited to, those shown below. [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124]

change

[0125]

change

[0126]

change

[0127]

change

[0128]

change

[0129]

change

[0130]

change

[0131]

change

[0132]

change

[0133]

change

[0134]

change

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] Examples of the cation of the iodonium salt represented by formula (1-2) include, but are not limited to, the following: [ka]

[0144] [ka]

[0145] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulae (1A) to (1D). [ka]

[0146] In formula (1A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A') which will be described later. 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0147] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0148] In formula (1A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or the like, and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is particularly preferably one having 6 to 30 carbon atoms.

[0149] R 111The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosyl groups; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, and nonyl. Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 38 carbon atoms, such as a carboxymethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0150] 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, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing hetero atoms include tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl groups.

[0151] Synthesis of sulfonium salts containing anions represented by formula (1A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable.

[0152] Examples of the anion represented by formula (1A) include the same anions as those exemplified as the anion represented by formula (1A) described in JP-A-2018-197853.

[0153] In formula (1B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0154] In formula (1C), R fc1 , R fc2 and R fc3are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 are groups that are bonded together and bonded to each other (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0155] In formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. The synthesis of sulfonium salts containing anions represented by formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0156] Examples of the anion represented by formula (1D) include the same anions as those exemplified as the anion represented by formula (1D) described in JP-A-2018-197853.

[0157] Although the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile groups in the base polymer, making it suitable for use as a photoacid generator.

[0158] As the photoacid generator, a compound represented by the following formula (2) can also be suitably used. [ka]

[0159] In formula (2), R 201 and R 202 R are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of these may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the groups represented by R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same rings as those exemplified above can be mentioned.

[0160] R 201 and R 202The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6 cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, an anthracenyl group, and the like; 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, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0161] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 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, and heptadecane-1,17-diyl group; cyclopentanediyl group, cyclohexene-1,18-diyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl; 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 groups. In addition, 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, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbylene group containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferred.

[0162] In formula (2), LA is a single bond, an ether bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0163] In formula (2), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that X A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0164] In formula (2), d is an integer of 0 to 3.

[0165] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0166] In formula (2'), L A is the same as above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each 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. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group include the same as those exemplified above. Each of x and y is independently an integer of 0 to 5, and z is an integer of 0 to 4.

[0167] Examples of the photoacid generator represented by formula (2) include the same compounds as those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-026980.

[0168] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents. Also, those represented by formula (2') are particularly preferred because of their extremely small acid diffusion.

[0169] The photoacid generator may also be a sulfonium salt or iodonium salt containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom, such as those represented by the following formula (3-1) or (3-2): [ka]

[0170] In formulas (3-1) and (3-2), p is an integer that satisfies 1≦p≦3. q and r are integers that satisfy 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer that satisfies 1≦q≦3, more preferably 2 or 3. r is preferably an integer that satisfies 0≦r≦2.

[0171] In formulas (3-1) and (3-2), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same or different.

[0172] In formulas (3-1) and (3-2), L 1 is a single bond, an ether bond, an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0173] In formulas (3-1) and (3-2), L 2represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0174] In formulas (3-1) and (3-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy 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. 401Dis 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 hydroxy 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, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyl group, and hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0175] Of these, R 401 Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0176] In formulas (3-1) and (3-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 3 and Rf 4 are preferably both fluorine atoms.

[0177] In formulas (3-1) and (3-2), R 402 ~R 406are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105 Examples of the hydrocarbyl group include the same as those exemplified above. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- groups of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. 402 and R 403 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is the same as that described in the explanation of formula (1-1) as R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to the rings exemplified above.

[0178] Examples of the cation of the sulfonium salt represented by formula (3-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (1-2).

[0179] Examples of the anion of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, those shown below. BI is the same as above. [ka]

[0180] [ka]

[0181]

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[0182]

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[0183]

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[0184]

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[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198]

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[0199]

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[0200]

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[0201]

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[0202] When the resist material of the present invention contains an additive acid generator, the amount of the additive acid generator is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. By including the repeating unit f in the base polymer and / or by including an additive acid generator, the resist material of the present invention can function as a chemically amplified resist material.

[0203] [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 below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. ethers such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, etc.; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate (a mixture of L-, D-, and DL-isomers), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether acetate, etc.; and lactones such as γ-butyrolactone.

[0204] In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer. The organic solvents may be used singly or in combination of two or more.

[0205] [Other ingredients] In addition to the above-mentioned components, the resist material of the present invention may also contain a quencher other than salt compound A (hereinafter also referred to as "other quenchers"), a surfactant, a dissolution inhibitor, a crosslinking agent, a water repellency improver, acetylene alcohols, etc.

[0206] Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in Japanese Patent No. 3790649 A. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0207] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imido acids, or methide acids fluorinated at the α-position are necessary for deprotecting the acid-labile groups of carboxylic acid esters, and salt exchange with onium salts not fluorinated at the α-position releases sulfonic acids or carboxylic acids not fluorinated at the α-position. Sulfonic acids and carboxylic acids not fluorinated at the α-position do not undergo deprotection reactions and therefore function as quenchers. Photodecomposition of the onium salt-type quenchers reduces quenching performance in exposed regions, improving acid activity. This improves contrast.

[0208] The salt compound A is highly effective in suppressing acid diffusion in both unexposed and exposed areas, but is less effective in improving contrast. By using the salt compound A in combination with the onium salt quencher, it is possible to achieve a good balance of low acid diffusion and high contrast.

[0209] Other examples of quenchers include the polymer-type quenchers described in JP 2008-239918 A. These quenchers enhance the rectangularity of the resist pattern by orienting on the surface of the resist film. Polymer-type quenchers also have the effect of preventing pattern thinning and rounding of the pattern top when a protective film for immersion lithography is applied.

[0210] When the resist composition of the present invention contains other quenchers, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The other quenchers may be used singly or in combination of two or more.

[0211] Examples of the surfactant include those described in paragraphs

[0165] and

[0166] of JP 2008-111103 A. Adding a surfactant can further improve or control the coatability of the resist material. When the resist material of the present invention contains the surfactant, the content thereof 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.

[0212] When the resist material of the present invention is a positive resist, the incorporation of a dissolution inhibitor can further increase the difference in dissolution rate between exposed and unexposed areas, thereby further improving resolution. Examples of dissolution inhibitors include compounds having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, containing two or more phenolic hydroxy groups in the molecule, in which the hydrogen atoms of the phenolic hydroxy groups have been substituted with acid labile groups at a rate of 0 to 100 mol % overall, and compounds containing carboxy groups in the molecule, in which the hydrogen atoms of the carboxy groups have been substituted with acid labile groups at an average rate of 50 to 100 mol % overall. Specific examples include compounds in which the hydroxyl groups or carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid have been substituted with acid labile groups. These compounds are described, for example, in paragraphs

[0155] to

[0178] of JP 2008-122932 A.

[0213] When the resist composition of the present invention is a positive resist composition and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, 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.

[0214] On the other hand, when the resist material of the present invention is negative-working, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Examples of crosslinking agents include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds, such as alkenyloxy groups, all substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives or may be introduced as pendant groups into polymer side chains. Hydroxy-containing compounds may also be used as crosslinking agents.

[0215] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0216] Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated, or a mixture thereof.

[0217] Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound of tetramethylolguanamine in which 1 to 4 methylol groups are methoxymethylated, or a mixture thereof; tetramethoxyethylguanamine, tetraacyloxyguanamine, a compound of tetramethylolguanamine in which 1 to 4 methylol groups are acyloxymethylated, or a mixture thereof; and the like.

[0218] Examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are methoxymethylated or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are acyloxymethylated or a mixture thereof, etc. Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated or a mixture thereof, tetramethoxyethyl urea, etc.

[0219] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0220] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0221] Examples of the compound containing an 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.

[0222] When the resist composition of the present invention is a negative resist composition and contains the crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The crosslinking agents may be used singly or in combination of two or more.

[0223] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without a top coat. Preferred examples of the water repellency improver include polymers containing fluorinated alkyl groups and polymers containing a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue, with those exemplified in JP-A Nos. 2007-297590 and 2008-111103 being more preferred. The water repellency improver must be soluble in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, polymers containing repeating units containing an amino group or an amine salt are highly effective in preventing acid evaporation during post-exposure baking (PEB) and preventing poor hole pattern opening after development. When the resist composition of the present invention contains the water repellency improver, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more.

[0224] Examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP 2008-122932 A. When the resist material of the present invention contains an acetylene alcohol, the content thereof is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more.

[0225] [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 can include a method comprising the steps of forming a resist film on a substrate using the resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0226] First, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2 μm. This is then prebaked 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.

[0227] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV radiation, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 approximately, more preferably 0.5 to 50 μC / cm 2 The resist material of the present invention is particularly suitable for fine patterning using high-energy rays such as KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0228] After the exposure, PEB may be performed on a hot plate or in an oven, preferably at 50 to 150° C. for 10 seconds to 30 minutes, more preferably at 60 to 120° C. for 30 seconds to 20 minutes.

[0229] After exposure or PEB, the exposed resist film is developed using a developer of an alkaline aqueous solution of 0.1 to 10% by weight, preferably 2 to 5% by weight, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dipping, puddling, or spraying, to form the desired pattern. In the case of a positive resist material, the irradiated portion dissolves in the developer, while the unexposed portion remains insoluble, forming the desired positive pattern on the substrate. In the case of a negative resist material, the opposite occurs: the irradiated portion becomes insoluble in the developer, while the unexposed portion dissolves.

[0230] A negative pattern can also be obtained by organic solvent development using a positive resist material containing a base polymer containing an acid labile group. The developer used in this case includes 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 crotonate, ethyl crotonate, Examples of the organic solvent 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 phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0231] After the development is completed, the resist film is rinsed. A solvent that is miscible with the developer but does not dissolve the resist film is preferred as the rinse solution. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0232] Examples of the alcohol having 3 to 10 carbon atoms 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 of such an alcohol 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.

[0233] Examples of the ether compound 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.

[0234] Examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptine, and octyne.

[0235] Examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0236] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0237] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist film during baking causes crosslinking of the shrink agent on the surface of the resist film, resulting in adhesion of the shrink agent to the sidewalls 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. Excess shrink agent is removed, and the hole pattern is shrunk. [Example]

[0238] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0239] The structures of the quenchers Q-1 to Q-46, the amine compound (Amine-1), and the fluorinated 1,3-diketone compound (F-AcAc-1) used in the resist materials are shown below. [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [ka]

[0249] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-4) Each monomer was combined and copolymerized in THF, a solvent, and the reaction solution was poured into methanol. The precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (polymers P-1 to P-4) with the following compositions. The resulting base polymers had the following compositions: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene).

[0250] [ka]

[0251] [Examples 1 to 53, Comparative Examples 1 to 6] Preparation and Evaluation of Resist Materials (1) Preparation of resist material Resist materials were prepared by filtering solutions containing the components dissolved according to the compositions shown in Tables 1 to 4 through a 0.2 μm filter. The resist materials of Examples 1 to 21, Examples 23 to 53, and Comparative Examples 1 to 5 were positive-working, while the resist materials of Example 22 and Comparative Example 6 were negative-working.

[0252] In Tables 1 to 4, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (DL-ethyl lactate)

[0253] Acid generator: PAG-1 to PAG-4 [ka]

[0254] Comparison quenchers: cQ-1 to cQ-6 [ka]

[0255] Blend quencher: bQ-1, bQ-2 [ka]

[0256] (2) EUV lithography evaluation Each resist material listed in Tables 1-4 was spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-on hard mask (SHB-A940, 43 wt % silicon) manufactured by Shin-Etsu Chemical Co., Ltd., and prebaked at 100°C for 60 seconds using a hot plate to produce a 50 nm thick resist film. The resist film was exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, 44 nm pitch on the wafer, +20% bias hole pattern mask), subjected to PEB on a hot plate at the temperatures listed in Tables 1-4 for 60 seconds, and developed for 30 seconds in a 2.38 wt % TMAH aqueous solution to produce 22 nm hole patterns in Examples 1-21, 23-53, and Comparative Examples 1-5, and 22 nm dot patterns in Example 22 and Comparative Example 6. Using a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose when a hole or dot dimension of 22 nm was measured was used to determine the sensitivity. The dimensions of 50 holes or dots were also measured, and the CDU was calculated by multiplying the standard deviation (σ) by three (3σ). The results are shown in Tables 1 to 4.

[0257] [Table 1]

[0258] [Table 2]

[0259] [Table 3]

[0260] [Table 4]

[0261] The results shown in Tables 1 to 4 demonstrate that the resist material of the present invention containing salt compound A has high sensitivity and improved CDU.

Claims

1. A resist material comprising a base polymer and a quencher, The resist material contains a quencher comprising a nitrogen-atom-containing compound in which an iodine-substituted aromatic ring is bonded to a nitrogen atom via a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group optionally containing at least one bond selected from an ester bond and an ether bond, and at least one compound selected from the group consisting of a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, and a fluorinated imide compound, or a salt compound selected from the group consisting of any of the salt compounds Q-36, Q-37, Q-39, Q-40, and Q-45 below. 【Chemical 1】

2. 2. The resist material according to claim 1, wherein the salt compound is represented by the following formula (A): 【Chemistry 2】 (In the formula, m and n are integers satisfying 1≦m≦5, 0≦n≦4, and 1≦m+n≦5. k 1 is an integer from 1 to 3. 2 is 1 or 2. X 1 is a carbon number of 1 to 20 (k 2 It is a (+1)-valent hydrocarbon group, and may contain at least one bond selected from an ester bond and an ether bond. R 1 represents a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B or -N(R 1A )-C(=O)-O-R 1B It is. 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. R 2 is a hydrogen atom, a nitro group, or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain at least one selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a halogen atom, and an amino group. 1 When is 1 or 2, two R 2 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom, or a nitrogen atom. 2 and X 1 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. R 3 and R 4 are each independently a hydrocarbyl group having 1 to 16 carbon atoms, a fluorinated hydrocarbyl group having 1 to 16 carbon atoms, a hydrocarbyloxy group having 1 to 16 carbon atoms, or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, and R 3 and R 4 At least one of the groups is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, some or all of whose hydrogen atoms may be substituted with at least one selected from a cyano group, a nitro group, a hydroxy group and a halogen atom other than a fluorine atom, and these —CH 2 A part of the - may be substituted with at least one bond selected from an ether bond, an ester bond and a thioether bond. X 2 is -C(H)= or -N=.

3. 2. The resist material according to claim 1, further comprising an acid generator that generates a sulfonic acid, an imide acid, or a methide acid.

4. The resist material according to claim 1, further comprising an organic solvent.

5. 2. The resist material according to claim 1, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): 【Chemistry 3】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 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 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and its —CH 2 A portion of the - may be substituted with an ether bond or an ester bond. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5.

6. 6. The resist material according to claim 5, which is a chemically amplified positive resist material.

7. 2. The resist material according to claim 1, wherein the base polymer does not contain any acid labile groups.

8. 8. The resist material of claim 7, which is a chemically amplified negative resist material.

9. The resist material according to claim 1, further comprising a surfactant.

10. 2. The resist material according to claim 1, wherein the base polymer further comprises a repeating unit represented by any one of the following formulas (f1) to (f3): 【Chemistry 4】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents 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 -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -O-C(=O)-. Z 21 is a saturated hydrocarbylene group having 1 to 12 carbon atoms, which may contain a carbonyl group, an ester bond, or an ether bond. Z 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 31 -, -C(=O)-O-Z 31 - or -C(=O)-NH-Z 31 - is. Z 31 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. M - is a non-nucleophilic counterion.)

11. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist material according to any one of claims 1 to 10; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

12. 12. The pattern forming method according to claim 11, wherein the high-energy beam is ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, an electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

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