Resist material and pattern forming method

Abstract

To provide a resist material having high sensitivity and improved LWR and CDU, and a pattern forming method using the same.SOLUTION: The resist material contains a base polymer containing a repeating unit (a) comprising: a substituted or unsubstituted arylsulfonic acid anion bonded to a polymer main chain having a group containing an iodine atom or a bromine atom; and an onium cation.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 finer at a rapid pace. This is because 5G high-speed communications and artificial intelligence (AI) are becoming more widespread, and high-performance devices are needed to process these. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is used to mass-produce 5 nm node devices. Furthermore, studies are underway to use EUV lithography for next-generation 3 nm node devices and the next-next generation 2 nm node devices, and Belgium's IMEC has announced the development of 1 nm and 0.7 nm devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem. In order to ensure resolution in fine patterns with dimensions of 45 nm or less, it has been proposed that not only improving the dissolution contrast, as has been proposed in the past, but also controlling acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials increase sensitivity and contrast by acid diffusion, if you try to suppress acid diffusion to the maximum extent possible by lowering the post-exposure bake (PEB) temperature or shortening the time, the sensitivity and contrast will decrease significantly.

[0004] The triangle trade-off relationship between sensitivity, resolution, and edge roughness (LWR) is shown. In order to improve the resolution, it is necessary to suppress the acid diffusion, but the sensitivity decreases as the acid diffusion distance becomes shorter.

[0005] It is effective to suppress acid diffusion by adding an acid generator that generates a bulky acid. Therefore, it has been proposed to incorporate a repeating unit derived from an onium salt having a polymerizable unsaturated bond into a polymer. In this case, the polymer also functions as an acid generator (polymer-bound acid generator). Patent Document 1 proposes a sulfonium salt in which a sulfonic acid is directly bonded to the main chain.

[0006] Resist materials containing a polymer having an onium salt structure with an iodine atom or a bromine atom in the linker portion between the polymer main chain and fluorosulfonic acid have been proposed (Patent Documents 2 and 3). Iodine atoms have high absorption in EUV light, and bromine atoms are ionized by EUV irradiation, both of which improve the sensitivity and the physical contrast.

[0007] A mechanism for the generation of acid in high-energy rays such as EB and EUV light has been proposed (Non-Patent Document 2). According to this, in EB or EUV exposure, the polymer is ionized, secondary electrons are generated and diffused, and these transfer energy to the acid generator to generate acid. Based on the resist pattern transfer results and simulations, the distance from the light absorption point to the point where acid is generated is estimated to be 2.4 nm (Non-Patent Document 3). This distance includes the diffusion distance of secondary electrons. In this document, the total of the acid diffusion distance and the diffusion distance from the light absorption point to the point where acid is generated is described as 4 to 8 nm when the PEB temperature is changed, so when acid diffusion is suppressed by applying low-temperature PEB or anion-bound PAG polymer, half of the diffusion distance is occupied by the diffusion from the light absorption point to the point where acid is generated. In other words, it can be said that it is important to control not only acid diffusion but also diffusion from the light absorption point to the point where acid is generated, that is, the diffusion of secondary electrons, in miniaturization.

[0008] The health effects of perfluoroalkyl substances (PFAS) have been pointed out, and there are moves to impose restrictions on the manufacture and sale of PFAS under the European REACH. Many compounds containing PFAS are currently used in semiconductor lithography. For example, materials containing PFAS are used in surfactants, acid generators, etc. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2006-178317 A [Patent Document 2] JP 2018-197853 A [Patent Document 3] JP 2019-008280 A [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Non-Patent Document 2] SPIE Vol. 5753 361 (2005) [Non-Patent Document 3] SPIE Vol. 7969 796904-1 (2011) Summary of the Invention [Problem to be solved by the invention]

[0011] In resist materials, there is a demand for the development of an acid generator that can improve the LWR of line patterns and the dimensional uniformity (CDU) of hole patterns while also improving sensitivity. To achieve this, the acid generator must have high decomposition efficiency during exposure, suppress acid diffusion, and have high affinity with alkaline developers.

[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, particularly a positive resist material, which has high sensitivity and improved LWR and CDU, and a pattern formation method using the same. [Means for solving the problem]

[0013] As a result of intensive research by the inventors to achieve the above object, it has been found that by using a base polymer containing a repeating unit a consisting of a substituted or unsubstituted arylsulfonic acid anion bonded to a polymer main chain having a group containing an iodine atom or a bromine atom, and an onium cation, the acid generator is directly excited by the absorption of iodine atoms or bromine atoms during exposure to generate acid. In the case of a direct excitation mechanism, since it is not affected by the diffusion of secondary electrons, Furthermore, it has been found that the low acid diffusibility due to the generation of sulfonic acid bonded to the polymer main chain by exposure, the high decomposition efficiency due to direct excitation by exposure due to absorption and ionization by iodine atoms or bromine atoms, and at the same time, the ability to suppress acid diffusion, and high affinity with an alkaline developer result in high sensitivity, low acid diffusion, high contrast, and low swelling properties, and thus LWR and CDU are improved, and a resist material having high sensitivity, excellent resolution, and a wide process margin can be obtained, thereby completing 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 containing a repeating unit a consisting of a substituted or unsubstituted arylsulfonate anion bonded to a polymer main chain having a group containing an iodine atom or a bromine atom, and an onium cation. 2. The resist material of 1, wherein the repeating unit a is represented by the following formula (a1) or (a2): [ka] (In the formula, m is an integer of 0 to 5. R A is a hydrogen atom or a methyl group. RB is a hydrogen atom or X 1 may be bonded to form a ring. X 1 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. X 2A is a divalent organic group having 1 to 24 carbon atoms which contains at least one iodine atom or bromine atom, and which may contain at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. X 2B is a monovalent organic group having 1 to 10 carbon atoms which contains at least one iodine atom or bromine atom, and which may contain at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. X 3 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. X 4 is a trivalent organic group having 1 to 12 carbon atoms, which may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. The circle R is an (m+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. R 1 represents a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. M + is a sulfonium cation or an iodonium cation. 3. The resist material of 1 or 2, wherein the base polymer further contains a repeating unit represented by the following formula (b1) or a repeating unit represented by the following formula (b2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1is 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, an ether bond, a lactone ring, a hydroxy group, and a halogen atom. 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 chlorine atom, a bromine atom, an iodine 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 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, and a portion of the -CH2- in the alkanediyl group 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. 4. The resist material of 3, which is a chemically amplified positive resist material. 5. A resist material according to any one of 1 to 4, further comprising an organic solvent. 6. A resist material according to any one of 1 to 5, further comprising a surfactant. 7. 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 6, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 8. The pattern formation method according to 7, wherein the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam (EB) or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0015] A resist material containing a base polymer containing a repeating unit a consisting of a substituted or unsubstituted arylsulfonate anion bonded to a polymer main chain having a group containing an iodine atom or bromine atom and an onium cation has improved sensitivity and contrast due to the iodine atom or bromine atom, a short acid diffusion distance due to the arylsulfonate anion bonded to the polymer main chain, and an improved alkali dissolution rate due to the generation of a carboxyl group, making it possible to construct a resist material with improved LWR and CDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Resist material] The resist material of the present invention includes a base polymer containing a repeating unit a consisting of a substituted or unsubstituted arylsulfonate anion and an onium cation bonded to a polymer main chain having a group containing an iodine atom or a bromine atom. The repeating unit a functions as an acid generator, and the base polymer is a polymer-bound acid generator.

[0017] [Base polymer] The repeating unit a is preferably one represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or one represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0018] In the formulae (a1) and (a2), m is an integer of 0 to 5.

[0019] In formulas (a1) and (a2), R A R is a hydrogen atom or a methyl group. B is a hydrogen atom or X 1 may be bonded to form a ring.

[0020] In formulas (a1) and (a2), X 1is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond.

[0021] In formula (a1), X 2A is a divalent organic group having 1 to 24 carbon atoms which contains at least one iodine atom or bromine atom, and which may contain at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom.

[0022] X 2AThe divalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbylene groups having 1 to 24 carbon atoms in which some or all of the hydrogen atoms have been substituted with iodine or bromine atoms. Examples of the hydrocarbylene groups having 1 to 24 carbon atoms include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-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, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,3-diyl, and tetradecane-1,4-diyl. alkanediyl groups such as tetradecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, and eicosane-1,20-diyl group; cyclopentanediyl group, methylcyclopentanediyl group, dimethylcyclopentanediyl group, trimethylcyclopentanediyl group, tetramethylcyclopentanediyl group, cyclic saturated hydrocarbylene groups such as arylcyclopentanediyl group, cyclohexanediyl group, methylcyclohexanediyl group, dimethylcyclohexanediyl group, trimethylcyclohexanediyl group, tetramethylcyclohexanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, biphenyldiyl group, methylbiphenyldiyl group, and dimethylbiphenyldiyl group; and groups obtained by combining these groups. 2A A part or all of the hydrogen atoms of X may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom;2A A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0023] In formula (a2), X 2B is a monovalent organic group having 1 to 10 carbon atoms which contains at least one iodine atom or bromine atom, and which may contain at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom.

[0024] X 2BThe monovalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbyl groups having 1 to 10 carbon atoms in which some or all of the hydrogen atoms have been substituted with iodine or bromine atoms. Examples of the hydrocarbyl group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 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, and n-decyl; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl groups. cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as a norbornyl group, a cyclopropylmethyl group, a cyclopropylethyl group, a cyclobutylmethyl group, a cyclobutylethyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a methylcyclopropyl group, a methylcyclobutyl group, a methylcyclopentyl group, a methylcyclohexyl group, an ethylcyclopropyl group, an ethylcyclobutyl group, an ethylcyclopentyl group, or an ethylcyclohexyl group; a vinyl group alkenyl groups having 2 to 10 carbon atoms, such as 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, nonenyl group, and decenyl group; alkynyl groups having 2 to 10 carbon atoms, such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, and decynyl group; cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group, ethylcyclopentenyl group, ethylcyclohexenyl group, nonenyl group, Examples of the alkyl group include cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, and a naphthyl group; aralkyl groups having 7 to 10 carbon atoms, such as a benzyl group, a phenethyl group, a phenylpropyl group, and a phenylbutyl group; and groups obtained by combining these groups.2B A part or all of the hydrogen atoms of X may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom; 2B A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0025] In formulas (a1) and (a2), X 3 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms.

[0026] In formula (a2), X 4 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 4 The trivalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further eliminating one hydrogen atom from a hydrocarbylene group having 1 to 12 carbon atoms. Examples of the hydrocarbylene group having 1 to 12 carbon atoms include those having 1 to 12 carbon atoms among the above-mentioned hydrocarbylene groups having 1 to 24 carbon atoms. In addition, X 4 A part or all of the hydrogen atoms of X may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom; 4 A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0027] In formulae (a1) and (a2), the circle R is an (m+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. Specific examples of the (m+2)-valent aromatic hydrocarbon group include groups obtained by eliminating (m+2) hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene.

[0028] In formulas (a1) and (a2), R 1 represents a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group.

[0029] Specific examples of the anion of the repeating unit a include, but are not limited to, those shown below. In the following formula, X BI is an iodine atom or a bromine atom. [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

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[0054] In formulas (a1) and (a2), M + is a sulfonium cation or an iodonium cation. The sulfonium cation is preferably one represented by the following formula (M-1), and the iodonium cation is preferably one represented by the following formula (M-2). [ka]

[0055] In formulas (M-1) and (M-2), R 2 ~R 6 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0056] R 2 ~R6 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0057] R 2 ~R 6 The hydrocarbyl group having 1 to 20 carbon atoms represented by the following formula may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of such alkyl groups include alkyl groups having 1 to 20 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, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; and an ethynyl group. 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, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, a n-propylnaphthyl group, an isopropylnaphthyl group, a 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.

[0058] 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- 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 mercapto 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, or the like.

[0059] Also, R 2 and R 3 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 preferably one having the structure shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0060] Specific examples of the sulfonium cation include, but are not limited to, those shown below. [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065]

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[0086] The iodonium cations include, but are not limited to, those shown below. [ka]

[0087] [ka]

[0088] As a synthesis method of the sulfonium salt type monomer that gives the repeating unit a, a method of ion-exchanging a salt consisting of the sulfonium cation and a weak acid anion with an ammonium salt having the anion can be mentioned. The sulfonium cation can be obtained by the method described in, for example, paragraphs

[0094] to

[0097] of JP-A-2022-68394. In the case of an iodonium salt type monomer, the same ion-exchange method as above can be mentioned.

[0089] In the case of a positive resist material, the base polymer preferably further 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 (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2). In the exposed area, not only the repeating unit b1 or b2 containing an acid labile group in the base polymer but also the repeating unit a containing an acid generator are accelerated in dissolution rate in a developer by a catalytic reaction, so that a positive resist material with extremely high sensitivity can be obtained. [ka]

[0090] In formulas (b1) and (b2), R A Each of Y is independently a hydrogen atom or a methyl group. 1Y 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, an ether bond, a lactone ring, a hydroxyl group, and a halogen atom. 2 is a single bond or an ester bond. 3 R is a single bond, an ether bond or an ester bond. 11 and R 12 R is each independently an acid labile group. 13 R is a fluorine atom, a chlorine atom, a bromine atom, an iodine 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. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and a part of the -CH2- in the alkanediyl group may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0091] Examples of monomers that provide the repeating unit b1 include, but are not limited to, those shown below. A and R 11 is the same as above. [ka]

[0092] [ka]

[0093] Examples of monomers that provide the repeating unit b2 include, but are not limited to, those shown below. A and R 12 is the same as above. [ka]

[0094] In formulas (b1) and (b2), R 11 and R 12 Examples of the acid labile group represented by the formula (I) include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0095] Typically, the acid labile group includes those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0096] In formulas (AL-1) and (AL-2), R L1 and R L2 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 or an unsaturated hydrocarbyl group having 2 to 40 carbon atoms, more preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms or an unsaturated hydrocarbyl group having 2 to 20 carbon atoms.

[0097] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0098] 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 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. L2 , R L3 and R L4Any 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 preferable, and an alicyclic ring is particularly preferable.

[0099] 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. L5 , R L6 and R L7 Any two of these may be bonded to each other and form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. The ring is preferably a ring having 4 to 16 carbon atoms, and particularly preferably an alicyclic ring, and the ring may have a double bond or a triple bond.

[0100] As the acid labile group represented by formula (AL-3), aromatic group-containing acid labile groups described in Japanese Patent No. 5655754, Japanese Patent No. 5655755, Japanese Patent No. 5655756, Japanese Patent No. 5407941, Japanese Patent No. 5434983, Japanese Patent No. 5565293, and JP-A-2007-279699, triple bond-containing acid labile groups described in Japanese Patent No. 2008-268741, and double bond- or triple bond-containing acid labile groups described in Japanese Patent No. 2021-50307 can also be used.

[0101] The base polymer may further include a repeating unit c containing a phenolic hydroxy group as an adhesive 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]

[0102] The base polymer may contain a repeating unit d 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 sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group. Examples of monomers that provide the repeating unit d include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] The base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or a derivative thereof. Examples of the monomer that gives the repeating unit e include, but are not limited to, those shown below.

Chemical formula

[0111] The base polymer may further contain a repeating unit f derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methylene indane, vinylpyridine or vinylcarbazole.

[0112] The base polymer essentially has the repeating unit a. When the repeating unit a is the repeating unit a1 or a2, the content ratios of the repeating units a1, a2, b, c, d, e and f are preferably 0≦a1≦0.5, 0≦a2≦0.5, 0<a1+a2≦0.5, 0≦b1≦0.8, 0≦b2≦0.8, 0.1≦b1+b2≦0.8, 0≦c≦0.9, 0≦d≦0.8, 0≦e≦0.8 and 0≦f≦0.5, more preferably 0≦a1≦0.4, 0≦a2≦0.4, 0.02≦a1+a2≦0.4, 0≦b1≦0.7, 0≦b2≦0.7, 0.15≦b1+b2≦0.7, 0≦c≦0.8, 0≦d≦0.7, 0≦e≦0.7 and 0≦f≦0.4, and still more preferably 0≦a1≦0.35, 0≦a2≦0.35, 0.05≦a1+a2≦0.35, 0≦b1≦0.65, 0≦b2≦0.65, 0.2≦b1+b2≦0.65, 0≦c≦0.7, 0≦d≦0.6, 0≦e≦0.6 and 0≦f≦0.3. Note that a1+a2+b1+b2+c+d+e+f = 1.0.

[0113] To synthesize the base polymer, for example, monomers that give the above-described repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to carry out polymerization.

[0114] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, and more preferably 5 to 20 hours.

[0115] 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.

[0116] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0117] As the base for the alkaline hydrolysis, ammonia water, triethylamine, etc. can be used. 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.

[0118] The base polymer has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of preferably 1000 to 500000, more preferably 2000 to 30000. When the Mw is within the above range, the resist film has good heat resistance and solubility in an alkaline developer.

[0119] In addition, when the base polymer has a wide molecular weight distribution (Mw / Mn), low and high molecular weight polymers are present, which may result in foreign matter being found on the pattern after exposure or deterioration of the pattern shape. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater, so in order to obtain a resist material suitable for 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.

[0120] In order to obtain narrow-dispersity polymers, living radical polymerization can be used in addition to conventional radical polymerization, including nitroxide-mediated radical polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization.

[0121] The base polymer may include two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0122] [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 above-mentioned components and the components described below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, 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, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diacetone alcohol, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103. Examples of the alkyl ester include ethers such as ethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono tert-butyl ether acetate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, propyl 2-hydroxyisobutyrate, and butyl 2-hydroxyisobutyrate, and lactones such as γ-butyrolactone.

[0123] In the resist material 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, based on 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more kinds.

[0124] [Acid generator] The positive resist material of the present invention may further contain an acid generator (hereinafter, also referred to as an additive acid generator) that generates a strong acid. The strong acid here means a compound having sufficient acidity to cause a deprotection reaction of an acid labile group of a base polymer. The acid generator may be, for example, a compound (photoacid generator) that generates an acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon irradiation with 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.

[0125] In addition, 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]

[0126] In formulas (1-1) and (1-2), R 101 ~R 105 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 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. 101 and R 102 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 rings represented by R 2 and R 3Examples of the ring that can be formed by bonding with the sulfur atom to which they are bonded include the same as those exemplified above.

[0127] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulas (1A) to (1D). [ka]

[0128] 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 fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0129] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0130] In formula (1A'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. fa1 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, etc., and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is preferably one having 6 to 30 carbon atoms.

[0131] R fa1The 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, n-propyl, isopropyl, n-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 the like. Examples of the alkyl groups include cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as an alkyl group, a norbornylmethyl group, a tricyclodecyl group, a tetracyclododecyl group, a tetracyclododecylmethyl group, and a dicyclohexylmethyl group; unsaturated 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.

[0132] 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- 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, or the like. Examples of hydrocarbyl groups containing a heteroatom include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0133] Synthesis of sulfonium salts containing an anion represented by formula (1A') is described in detail in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. In addition, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0134] Examples of the anion represented by formula (1A) include the same anions as those exemplified as the anion represented by formula (1A) in JP 2018-197853 A.

[0135] 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 fa1 Examples of the hydrocarbyl group represented by the formula 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 (-CF2-SO2-N - -SO2-CF2-) may 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.

[0136] 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 fa1 Examples of the hydrocarbyl group represented by the formula 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 means that the groups (-CF2-SO2-C - -SO2-CF2-) may 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.

[0137] 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 fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0138] The synthesis of a sulfonium salt containing an anion represented by formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0139] Examples of the anion represented by formula (1D) include the same anions as those exemplified as the anion represented by formula (1D) in JP 2018-197853 A.

[0140] 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 group in the base polymer, and can therefore be used as a photoacid generator.

[0141] Furthermore, as the photoacid generator, a compound represented by the following formula (2) can also be suitably used. [ka]

[0142] 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 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 as defined in the description of formulae (M-1) and (M-2) as R 2 and R 3 Examples of the ring that can be formed by bonding with the sulfur atom to which they are bonded include the same as those exemplified above.

[0143] 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, or 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, a tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decyl group, and an adamantyl group; aryl groups having 6 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, and an anthracenyl group; and groups obtained by combining these. 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- 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 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, or the like.

[0144] 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 a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; a cyclopentanediyl group, a cyclohexanediyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as axanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups having 6 to 30 carbon atoms, such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group; 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 -CH2- 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, so that the hydrocarbylene 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. As the heteroatom, an oxygen atom is preferable.

[0145] In formula (2), LA is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or 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.

[0146] 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. A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0147] In formula (2), k is an integer of 0 to 3.

[0148] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0149] In formula (2'), L A is the same as above. X e R 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 fa1 Examples of the hydrocarbyl group represented by the formula: x and y each independently represent an integer of 0 to 5, and z represents an integer of 0 to 4.

[0150] Examples of the photoacid generator represented by formula (2) include the same as those exemplified as the photoacid generator represented by formula (2) in JP2017-026980A.

[0151] 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, while those represented by formula (2') are particularly preferred because of their extremely small acid diffusion.

[0152] The photoacid generator may be a sulfonium salt or an iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom. Examples of such salts include those represented by the following formula (3-1) or (3-2). [ka]

[0153] In formulas (3-1) and (3-2), p is an integer satisfying 1≦p≦3. q and r are integers satisfying 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer satisfying 1≦q≦3, more preferably 2 or 3. r is preferably an integer satisfying 0≦r≦2.

[0154] In formulas (3-1) and (3-2), X BI represents an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same or different.

[0155] In formulas (3-1) and (3-2), L 1 is a single bond, an ether bond or 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.

[0156] 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.

[0157] 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 10 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 R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may 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, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy 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.

[0158] Of these, R 401 Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, and the like are preferred.

[0159] In formulas (3-1) and (3-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, at least one of which 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.

[0160] 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 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) 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 group, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- 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 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 as defined by R 2 and R 3 Examples of the ring that can be formed by bonding with the sulfur atom to which they are bonded include the same as those exemplified above.

[0161] The cation of the sulfonium salt represented by formula (3-1) is preferably M in formulas (a1) and (a2). + The sulfonium cation represented by formula (3-2) may be the same as that exemplified above. The cation of the iodonium salt represented by formula (3-2) may be the same as that exemplified above. + Examples of the iodonium cation represented by the formula:

[0162] 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. In the following formula, X BI is the same as above. [ka]

[0163]

change

[0164]

change

[0165]

change

[0166]

change

[0167]

change

[0168]

change

[0169]

change

[0170]

change

[0171]

change

[0172]

change

[0173]

change

[0174]

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[0175]

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[0176]

change

[0177]

change

[0178]

change

[0179]

change

[0180]

change

[0181]

change

[0182]

change

[0183]

change

[0184] [ka]

[0185] As the photoacid generator, a sulfonium salt or iodonium salt of fluorobenzenesulfonic acid bonded to iodized benzoic acid represented by the following formula (3-3) or (3-4) can also be used. [ka]

[0186] In formulas (3-3) and (3-4), n1 is an integer of 1 to 5. n2 is an integer of 0 to 3. n3 is an integer of 1 to 4.

[0187] In formulas (3-3) and (3-4), R 411 is a hydroxy group, a carboxyl group, an alkoxycarbonyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an alkoxy group, or -N(R 411A )-C(=O)-R 411B Or -N(R 411A )-C(=O)-OR 411B and R 411A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 411B represents 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.

[0188] In formulas (3-3) and (3-4), L 3 is a single bond or a divalent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0189] In formulas (3-3) and (3-4), Rf 11 is a fluorine atom or a trifluoromethyl group.

[0190] In formulas (3-3) and (3-4), R 412 ~R 416 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 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) 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 group, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- 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 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 as defined by R 2 and R 3 Examples of the ring that can be formed by bonding with the sulfur atom to which they are bonded include the same as those exemplified above.

[0191] The cation of the sulfonium salt represented by formula (3-3) is, for example, M + The sulfonium cation represented by formula (3-4) may be the same as that exemplified above. The cation of the iodonium salt represented by formula (3-4) may be the same as that exemplified above. + Examples of the iodonium cation represented by the formula:

[0192] Examples of the anion of the onium salt represented by formula (3-3) or (3-4) include, but are not limited to, those shown below. [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] When the resist material of the present invention contains the additive acid generator, the content thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The additive acid generator may be used alone or in combination of two or more types. When the base polymer contains the repeating unit a and / or when the additive acid generator is contained, the resist material of the present invention can function as a chemically amplified resist material.

[0198] [Quencher] The resist material of the present invention may contain a quencher. The quencher refers to a compound that can trap the acid generated by the acid generator in the resist material, thereby preventing the acid from diffusing into unexposed areas.

[0199] The quencher may be a conventional basic compound. 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. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate group described in JP-A-3790649 are preferred. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

[0200] Further, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a sulfonic acid, a carboxylic acid, or a fluorinated alkoxide, which is not fluorinated at the α-position, as described in JP-A-2008-158339. A sulfonic acid, an imide acid, or a methide acid, which is fluorinated at the α-position, is necessary for deprotecting an acid labile group of a carboxylate ester, but a sulfonic acid, a carboxylic acid, or a fluorinated alcohol, which is not fluorinated at the α-position, is released by salt exchange with an onium salt, which is not fluorinated at the α-position. A sulfonic acid, a carboxylic acid, and a fluorinated alcohol, which is not fluorinated at the α-position, do not cause a deprotection reaction, and therefore function as a quencher.

[0201] Examples of such quenchers include compounds represented by the following formula (4-1) (onium salts of sulfonic acids not fluorinated at the α-position), compounds represented by the following formula (4-2) (onium salts of carboxylic acids), and compounds represented by the following formula (4-3) (onium salts of alkoxides). [ka]

[0202] In formula (4-1), R 501 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0203] R 501 The hydrocarbyl group having 1 to 40 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 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, or 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, a tricyclo[5.2.1.0 2,6 ]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as decyl group, adamantyl group, and adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms, such as cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert and aryl groups having 6 to 40 carbon atoms, such as arylphenyl groups (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl groups (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl groups (dimethylnaphthyl group, diethylnaphthyl group, etc.); and aralkyl groups having 7 to 40 carbon atoms, such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, etc.

[0204] 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- 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 cyano 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 the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0205] In formula (4-2), R 502 R is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 502 The hydrocarbyl group represented by R 501 Examples of the hydrocarbyl group include the same as those exemplified above. Other specific examples include fluorinated alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0206] In formula (4-3), R 503represents a saturated hydrocarbyl group having 1 to 8 carbon atoms and at least three fluorine atoms, or an aryl group having 6 to 10 carbon atoms and at least three fluorine atoms, which may contain a nitro group.

[0207] In formulas (4-1), (4-2) and (4-3), Mq + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation. Examples of the sulfonium cation include the sulfonium cations described in JP-A-2017-219836.

[0208] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (4-4) can also be suitably used. [ka]

[0209] In formula (4-4), R 511 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or 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, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 511A )-C(=O)-R 511B Or -N(R 511A )-C(=O)-OR 511B R 511A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 511B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0210] In formula (4-4), x' is an integer of 1 to 5. y' is an integer of 0 to 3. z' is an integer of 1 to 3. L 11is a single bond or a (z'+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The saturated hydrocarbyl group, the saturated hydrocarbyloxy group, the saturated hydrocarbylcarbonyloxy group, and the saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y' and / or z' is 2 or more, each R 511 may be the same or different from each other.

[0211] In formula (4-4), R 512 , R 513 and R 514 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 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0212] Specific examples of the compound represented by formula (4-4) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0213] Another example of the quencher is the polymer-type quencher described in JP 2008-239918 A. This quencher enhances the rectangularity of the resist pattern by being oriented on the surface of the resist film. The polymer-type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0214] Furthermore, betaine-type sulfonium salts described in Japanese Patent No. 6848776 and Japanese Patent Application Publication No. 2020-37544, fluorine-free methide acids described in Japanese Patent Application Publication No. 2020-55797, sulfonium salts of sulfonamides described in Japanese Patent Application Publication No. 5807552, and sulfonium salts of sulfonamides containing iodine atoms described in Japanese Patent Application Publication No. 2019-211751 can also be used as quenchers.

[0215] When the resist composition of the present invention contains the quencher, 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 quencher may be used alone or in combination of two or more kinds.

[0216] [Other ingredients] The resist material of the present invention may contain, in addition to the above-mentioned components, a surfactant, a dissolution inhibitor, a water repellency enhancer, acetylene alcohols, and the like.

[0217] Examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP 2008-111103 A. The addition of 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 relative to 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more kinds.

[0218] When the resist material of the present invention is a positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by adding a dissolution inhibitor, and the resolution can be further improved. The dissolution inhibitor includes a compound having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid labile groups at a ratio of 0 to 100 mol % as a whole, or a compound containing a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl groups are substituted with acid labile groups at an average ratio of 50 to 100 mol % as a whole. Specific examples include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalene carboxylic acid, adamantane carboxylic acid, hydroxyl groups of cholic acid, and compounds in which hydrogen atoms of carboxyl groups are substituted with acid labile groups, and the like, and are described, for example, in paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0219] When the resist material of the present invention is a positive type and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more kinds.

[0220] The water repellency improver improves the water repellency of the resist film surface, and can be used in immersion lithography without using a topcoat. As the water repellency improver, a polymer containing a fluorinated alkyl group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like are preferred, and those exemplified in JP-A-2007-297590 and JP-A-2008-111103 are more preferred. The water repellency improver needs to be dissolved 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 the water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt is highly effective in preventing the evaporation of the acid in the PEB and preventing the opening failure of the hole pattern 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, based on 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more kinds.

[0221] 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 is preferably 0 to 5 parts by mass relative to 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more kinds.

[0222] The resist material of the present invention can be prepared by thoroughly mixing the components, adjusting the sensitivity and film thickness to a predetermined range, and then filtering the resulting solution. The filtration step is important for reducing defects in the resist pattern after development. The diameter of the membrane for filtration is preferably 1 μm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. The smaller the diameter, the more the occurrence of defects in a fine pattern can be suppressed. Examples of the membrane material include tetrafluoroethylene, polyethylene, polypropylene, nylon, polyurethane, polycarbonate, polyimide, polyamideimide, polysulfone, and the like. Membranes with improved adsorption ability can also be used by modifying the surface of tetrafluoroethylene, polyethylene, polypropylene, and the like. Since tetrafluoroethylene, polyethylene, and polypropylene are non-polar, they do not have the ability to adsorb gels or metal ions due to polarity, unlike membranes such as nylon, polyurethane, polycarbonate, and polyimide, but the ability to adsorb gels and metal ions can be increased by surface modification with functional groups having polarity. In particular, by surface modification of polyethylene and polypropylene membranes, which can form membranes with smaller diameters, not only fine particles but also particles and metal ions having polarity can be reduced. A laminate of films of different materials or films with different hole sizes may also be used.

[0223] A membrane having an ion exchange ability can also be used. In the case of an ion exchange membrane that adsorbs cations, it is possible to reduce metal impurities by adsorbing metal ions.

[0224] When performing filtration, multiple filters can be connected. The types and diameters of the membranes of the multiple filters can be the same or different. Filtration can be performed in piping connecting multiple containers, or circulating filtration can be performed by providing an outlet and an inlet in one container and connecting the piping. Filters performing filtration can be connected by serial piping or parallel piping.

[0225] [Pattern formation method] When the resist material of the present invention is used in various integrated circuit manufacturing, known lithography techniques can be applied.For example, as a pattern forming method, the method includes the steps of forming a resist film on a substrate using the above-mentioned 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 anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, CrN, MoSi2, SiO2, MoSi2 laminated film, Ta, TaN, TaCN, Ru, Nb, Mo, Mn, Co, Ni, or alloys thereof, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so that the coating film thickness is 0.01 to 2 μm. This is pre-baked on a hot plate, preferably at 60 to 150 ° C, for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C, for 30 seconds to 20 minutes, to form a resist film.

[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, synchrotron radiation, etc. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm2, 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 300 μC / cm 2 Approximately, more preferably 0.5 to 200 μC / cm 2The resist material of the present invention is 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 or may not be performed on a hot plate or in an oven, preferably at 30 to 150° C. for 10 seconds to 30 minutes, more preferably at 50 to 120° C. for 30 seconds to 20 minutes.

[0229] After exposure or PEB, the exposed resist film is developed by a conventional method such as a dip method, a puddle method, or a spray method using a developer of an alkaline aqueous solution of 0.1 to 10 mass%, preferably 2 to 5 mass%, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH) for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, to form a desired pattern. In the case of a positive resist material, the portion irradiated with light dissolves in the developer, and the portion not exposed to light does not dissolve, forming a desired positive pattern on the substrate. In the case of a negative resist material, the opposite is true to the case of a positive resist material, where the portion irradiated with light becomes insoluble in the developer, and the portion not exposed to light 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 is 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] At the end of the development, rinsing is performed. As the rinsing liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferable. As such a solvent, 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 are preferably used.

[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 alcohols 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, cyclononane, etc. Examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of the alkynes having 6 to 12 carbon atoms include hexine, heptine, octyne, etc.

[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 pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and the shrink agent crosslinks on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, and the shrink agent adheres 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, and excess shrink agent is removed to reduce the hole pattern. EXAMPLES

[0238] The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[0239] The monomers PM-1 to PM-18, cPM-1, cPM-2, AM-1 to AM-7, and FM-1 used in the synthesis of the base polymer are as follows. PM-1 to PM-14 were synthesized by ion exchange between the ammonium salt of fluorinated benzenesulfonic acid, which gives the anion shown below, and the sulfonium chloride, which gives the cation shown below. The Mw of the polymer is a polystyrene-equivalent value measured by GPC using THF as a solvent. [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [Synthesis Example 1] Synthesis of Polymer P-1 In a 2L flask, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 4.8g of 4-hydroxystyrene, 8.8g of PM-1, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-1. The composition of polymer P-1 was as follows: 13 C-NMR and1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0249] [Synthesis Example 2] Synthesis of Polymer P-2 In a 2L flask, 9.0g of 1-vinyl-1-cyclopentyl methacrylate, 4.8g of 3-hydroxystyrene, 8.6g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-2. The composition of polymer P-2 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0250] [Synthesis Example 3] Synthesis of Polymer P-3 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 11.6g of PM-3, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-3. The composition of polymer P-3 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0251] [Synthesis Example 4] Synthesis of polymer P-4 In a 2L flask, 8.1g of AM-2, 2.7g of AM-4, 4.8g of 3-hydroxystyrene, 10.1g of PM-4, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-4. The composition of polymer P-4 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0252] [Synthesis Example 5] Synthesis of Polymer P-5 In a 2L flask, 11.6g of AM-3, 5.2g of 3-hydroxystyrene, 8.3g of PM-5, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-5. The composition of polymer P-5 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0253] [Synthesis Example 6] Synthesis of Polymer P-6 In a 2L flask, 8.3g of AM-5, 4.8g of 3-hydroxystyrene, 8.2g of PM-6, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-6. The composition of polymer P-6 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0254] [Synthesis Example 7] Synthesis of polymer P-7 In a 2L flask, 11.1g of AM-1, 3.4g of 3-hydroxystyrene, 3.2g of monomer FM-1, 10.7g of PM-7, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-7. The composition of polymer P-7 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0255] [Synthesis Example 8] Synthesis of polymer P-8 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 9.1g of PM-8, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-8. The composition of polymer P-8 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0256] [Synthesis Example 9] Synthesis of Polymer P-9 In a 2L flask, 12.1g of AM-6, 4.8g of 4-hydroxystyrene, 9.2g of PM-9, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-9. The composition of polymer P-9 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0257] [Synthesis Example 10] Synthesis of Polymer P-10 In a 2L flask, 12.0g of AM-7, 4.8g of 4-hydroxystyrene, 8.9g of PM-10, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-10. The composition of polymer P-10 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0258] [Synthesis Example 11] Synthesis of Polymer P-11 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 7.7g of PM-11, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-11. The composition of polymer P-11 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0259] [Synthesis Example 12] Synthesis of Polymer P-12 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 11.1g of PM-12, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-12. The composition of polymer P-12 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0260] [Synthesis Example 13] Synthesis of Polymer P-13 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 12.0g of PM-13, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-13. The composition of polymer P-13 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0261] [Synthesis Example 14] Synthesis of polymer P-14 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 11.9g of PM-14, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-14. The composition of polymer P-14 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0262] [Synthesis Example 15] Synthesis of Polymer P-15 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 10.8g of PM-15, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-15. The composition of polymer P-15 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0263] [Synthesis Example 16] Synthesis of Polymer P-16 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 11.4g of PM-16, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-16. The composition of polymer P-16 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0264] [Synthesis Example 17] Synthesis of polymer P-17 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 11.0g of PM-17, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-17. The composition of polymer P-17 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0265] [Synthesis Example 18] Synthesis of Polymer P-18 In a 2L flask, 11.1g of AM-1, 4.8g of 3-hydroxystyrene, 10.1g of PM-18, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-18. The composition of polymer P-18 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0266] [Comparative Synthesis Example 1] Synthesis of Comparative Polymer cP-1 Comparative polymer cP-1 was synthesized in the same manner as in Synthesis Example 1, except that PM-1 was changed to cPM-1. [ka]

[0267] [Comparative Synthesis Example 2] Synthesis of Comparative Polymer cP-2 Comparative polymer cP-2 was synthesized in the same manner as in Synthesis Example 1, except that PM-1 was changed to cPM-2. [ka]

[0268] [Examples 1 to 21, Comparative Examples 1 and 2] Preparation of resist materials and their evaluation (1) Preparation of resist material A resist material was prepared by filtering a solution in which each component was dissolved according to the composition shown in Table 1 through a 0.2 μm filter.

[0269] In Table 1, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (Ethyl lactate) DAA (Diacetone Alcohol)

[0270] Acid generator: PAG-1~PAG-3 [ka]

[0271] Quencher: Q-1~Q-6 [ka]

[0272] (2) EUV lithography evaluation Each resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the substrate was pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 60 nm. The resist film was exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a hole pattern mask with a pitch of 40 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at the temperature shown in Table 1 for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with a dimension of 20 nm. Using a Hitachi High-Technologies Corporation CD-SEM (CG6300), the exposure dose when a hole dimension of 20 nm was formed was measured and used as the sensitivity. The dimensions of 50 holes were also measured, and the CDU was calculated by multiplying the standard deviation (σ) by three (3σ). The results are shown in Table 1.

[0273] [Table 1]

[0274] The results shown in Table 1 show that the resist material of the present invention, which contains a base polymer including a repeating unit a composed of a substituted or unsubstituted arylsulfonate anion bonded to a polymer main chain having a group containing an iodine atom or a bromine atom, and an onium cation, has good CDU.

Claims

1. A resist material comprising a base polymer containing a repeating unit a consisting of a substituted or unsubstituted arylsulfonate anion and an onium cation bonded to a polymer main chain having a group containing an iodine atom or a bromine atom.

2. 2. The resist material according to claim 1, wherein the repeating unit a is represented by the following formula (a1) or (a2): 【Chemistry 1】 (In the formula, m is an integer from 0 to 5. R A is a hydrogen atom or a methyl group. R B is a hydrogen atom or X 1 may be bonded to form a ring. X 1 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. X 2A is a divalent organic group having 1 to 24 carbon atoms which has at least one iodine atom or bromine atom and may have at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom. X 2B is a monovalent organic group having 1 to 10 carbon atoms which contains at least one iodine atom or bromine atom and may contain at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom. X 3 represents a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. X 4 is a trivalent organic group having 1 to 12 carbon atoms, which may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. The circle R is an (m+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. R 1 represents a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. M + is a sulfonium cation or an iodonium cation.

3. The resist material according to claim 1 , wherein the base polymer further comprises a repeating unit represented by the following formula (b1) or a repeating unit represented by the following formula (b2): 【Chemistry 2】 (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, an ether bond, a lactone ring, a hydroxyl group, and a halogen atom. 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 chlorine atom, a bromine atom, an iodine 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 the -CH 2 A part of the - may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5.

4. The resist material of claim 3 which is a chemically amplified positive resist material.

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

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

7. 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 6; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

8. 8. The method for forming a pattern according to claim 7, wherein the high-energy beam is a KrF excimer laser beam, an ArF excimer laser beam, an electron beam or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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