Photoacid generator and resin composition for photolithography

Abstract

To provide: a novel photoacid generator which has high photosensitivity to EUV, EB, X-rays and the like; and a resin composition for photolithography containing the photoacid generator.SOLUTION: The present invention provides: a photoacid generator (P) containing a selenonium salt represented by a general formula (1); and a resin composition for photolithography containing the photoacid generator.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photoacid generator and a resin composition for photolithography. More specifically, the present invention relates to a photoacid generator containing a selenonium salt suitable for generating a strong acid by the action of extreme ultraviolet rays (EUV) or electron beams (EB), and a resin composition for photolithography containing the same. [Background technology]

[0002] A photoacid generator is a general term for a compound that generates an acid by decomposing when irradiated with active energy rays such as light, electron beams, or X-rays, and the acid generated by irradiation with active energy rays is used as an active species in various reactions such as polymerization, crosslinking, deprotection reactions, etc. Specific examples include polymerization of cationic polymerizable compounds, crosslinking reactions with phenolic resins in the presence of crosslinking agents, and acid-catalyzed deprotection reactions of polymers in which a protecting group has been introduced into an alkali-soluble resin.

[0003] Photolithography technology is widely used in the manufacture of electronic components and the formation of semiconductor elements, and chemically amplified resists that utilize acid generated from photoacid generators are widely used. Mass production of semiconductor elements is carried out using KrF excimer lasers and ArF excimer lasers as exposure light sources, but in recent years, with the further miniaturization of patterns, short-wavelength (high-energy) EUV (extreme ultraviolet), EB (electron beam), X-rays, etc. are also being considered.

[0004] As the wavelength of light sources becomes shorter, the number of photons per unit energy decreases, so there is still a demand for highly sensitive photoacid generators that can effectively utilize the limited photons. However, when photoacid generators such as triphenylsulfonium salts, which are commonly used in chemically amplified resists for KrF excimer lasers and ArF excimer lasers, are used in EUV and EB lithography, their photosensitivity is insufficient, so highly sensitive photoacid generators specialized for EUV, EB, X-rays, etc. have been developed. As photoacid generators for EUV resists, photoacid generators with characteristic anions (Patent Document 1) and photoacid generators with adjusted cation structures (Patent Documents 2, 3, and 4) have been proposed, but the sensitivity to EUV in all cases is insufficient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-237176 A [Patent Document 2] Patent No. 5678747 [Patent Document 3] JP 2014-234348 A [Patent Document 4] JP 2019-201404 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above background, a first object of the present invention is to provide a new photoacid generator having high photosensitivity to EUV, EB, X-rays, etc. A second object of the present invention is to provide a resin composition for photolithography comprising the above photoacid generator. [Means for solving the problem]

[0007] As a result of investigations aimed at achieving the above object, the present inventors arrived at the present invention. That is, the present invention relates to a photoacid generator (P) characterized by containing a selenonium salt represented by the following general formula (1); and a resin composition for photolithography (Q) containing the photoacid generator (P).

[0008] [ka]

[0009] [In formula (1), X1, X2, and X3 each independently represent a halogen atom, a hydroxy group, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an arylthio group having 6 to 14 carbon atoms, or an arylseleno group having 6 to 14 carbon atoms (a part or all of the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, and arylseleno groups may be substituted with fluorine atoms), y1, y2, and y3 each independently represent an integer of 0 to 5, and A represents a monovalent anion.] Effect of the Invention

[0010] The photoacid generator (P) of the present invention has high EUV absorption and easy decomposition due to the ease of dissociation of the carbon-selenium bond by using selenium as the central element of the onium skeleton. This allows the photoacid generator (P) to be easily decomposed by irradiation with EUV or EB, and to generate various acids including strong acids such as sulfonic acid. In addition, the sensitivity, solubility, and storage stability can be controlled by introducing substituents into X1 to X3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The photoacid generator (P) of the present invention contains a selenonium salt represented by the following general formula (1).

[0012] [ka]

[0013] [In formula (1), X1, X2, and X3 each independently represent a halogen atom, a hydroxy group, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an arylthio group having 6 to 14 carbon atoms, or an arylseleno group having 6 to 14 carbon atoms (a part or all of the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, and arylseleno groups may be substituted with fluorine atoms), y1, y2, and y3 each independently represent an integer of 0 to 5, and A represents a monovalent anion.]

[0014] In formula (1), X1, X2, and X3 each independently represent a halogen atom, a hydroxy group, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an arylthio group having 6 to 14 carbon atoms, or an arylseleno group having 6 to 14 carbon atoms (a portion or all of the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups and arylseleno groups may be substituted with fluorine atoms).

[0015] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0016] Examples of the alkyl group having 1 to 18 carbon atoms include linear, branched, or cyclic alkyl groups (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, cyclopentyl, cyclohexyl, octyl, decanyl, decalinyl, norbornanyl, adamantyl, etc.) and the like. In addition, the hydrogen atoms of these groups may be partially or completely substituted with fluorine.

[0017] Examples of the alkoxy group having 1 to 18 carbon atoms include linear or branched alkoxy groups having 1 to 18 carbon atoms (methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, dodecyloxy, octadecyloxy, etc.), etc. In addition, the hydrogen atoms of these groups may be partially or completely substituted with fluorine.

[0018] Examples of the aryl group having 6 to 14 carbon atoms include aryl groups such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-azulenyl group, an anthracenyl group, and a phenanthrenyl group. In addition, the hydrogen atoms of these groups may be partially or completely substituted with fluorine.

[0019] Examples of the aryloxy group having 6 to 14 carbon atoms include phenoxy, naphthyloxy, and anthracenyloxy groups. In addition, the hydrogen atoms in these groups may be partially or completely substituted with fluorine.

[0020] Examples of the arylthio group having 6 to 14 carbon atoms include phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-ethylphenylthio, naphthylthio, and anthracenylseleno groups. In addition, the hydrogen atoms in these groups may be partially or completely substituted with fluorine.

[0021] Examples of the arylseleno group having 6 to 14 carbon atoms include a phenylseleno group, a naphthylseleno group, and an anthracenylseleno group. In addition, the hydrogen atoms in these groups may be partially or completely substituted with fluorine.

[0022] In formula (1), from the viewpoints of sensitivity, stability, and ease of availability, X1, X2, and X3 are preferably a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms (the hydrogen atoms of these alkyl and aryl groups may be partially or completely substituted with fluorine atoms), and more preferably F, CF3, C2F5, C3F7, C4F9, or C6F5.

[0023] In formula (1), y1, y2, and y3 each independently represent an integer of 0 to 5, and preferably an integer of 0 to 2.

[0024] In formula (1), A - represents a monovalent anion. The monovalent anion is Cl. - , Br - , SbF6 - , PF6 - , BF4 - , (CF3CF2)3PF3 - , (CF3CF2)2PF4 - , (CF3CF2)PF5 - , (C6F5)4B - , {(CF3)2C6H3}4B - , (C6F5)4Ga - , {(CF3)2C6H3}4Ga - , (CF3SO2)3C - , (CF3SO2)2N - , (C4F9SO2)2N - and R 1 SO3 - etc.

[0025] R 1 SO3 - Examples of the sulfonate anion represented by the formula (2) include trifluoromethanesulfonate anion (triflate), pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonafluorobutanesulfonate anion (nonaflate), pentafluorophenylsulfonate anion, p-toluenesulfonate anion, benzenesulfonate anion, camphorsulfonate anion, methanesulfonate anion, ethanesulfonate anion, propanesulfonate anion, butanesulfonate anion, and sulfonate anion represented by the following general formula (2):

[0026] [ka]

[0027] [In formula (2), R 2 is a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms (some or all of the hydrogen atoms may be substituted with fluorine, and some of the methylene chain may be substituted with -O-, -CO-, -COO-, -OCO-, -OCOO-, -S-, -SO- or -SO2- groups, and may form a bicyclo or spiro structure), R 3 and R 4 are each independently a hydrogen atom, a fluorine atom or a fluoroalkyl group having 1 to 4 carbon atoms, and Z is a single bond or a linear or branched alkyl group having 1 to 8 carbon atoms (a part or all of the hydrogen atoms may be substituted with fluorine, and a part of the methylene chain may be substituted with -O-, -CO-, -COO-, -OCO-, -OCOO-, -S-, -SO-, or -SO2- group).

[0028] A ‐ From the viewpoints of sensitivity, roughness reduction, and ease of availability, 1 SO3 - Among the anions represented by the formula (2), trifluoromethanesulfonate anion (triflate), nonafluorobutanesulfonate anion (nonaflate), or the anion represented by the formula (2), R 3 and R 4 More preferably, is a fluorine atom or a fluoroalkyl group having 1 to 4 carbon atoms.

[0029] The method for synthesizing the selenonium salt of the present invention is not particularly limited as long as the target product can be synthesized. For example, the selenonium salt can be produced by the production method described below.

[0030] [ka]

[0031] In the above reaction formula, X1 to X3 and y1 to y3 are the same as X1 to X3 and y1 to y3 in the photoacid generator (P) represented by general formula (1). In the first step, an arylselenol, an aryl bromide, and a base are reacted in an organic solvent (DMAc, etc.) at a reaction temperature of 60 to 140° C. for 6 to 48 hours.

[0032] The base is not particularly limited as long as it can abstract a proton from SeH in the arylselenol, but examples include alkali metal hydroxides (KOH, NaOH, etc.), alkali metal salts of carbonate anion (K2CO3, Na2CO3, etc.), organic bases (diazabicycloundecene, triethylamine, pyridine, etc.), and alkali metal hydrides (LiH, NaH, etc.).

[0033] The second step reaction may be carried out immediately after the first step reaction, or after isolating (and purifying as necessary) the precursor selenide. The precursor selenide and an organic solvent (acetonitrile, dioxane, tetrahydrofuran, DMF, etc.) are mixed and stirred, and the mixture is reacted with diaryliodonium triflate. The reaction time is 1 to 50 hours, and the reaction temperature is 80 to 120°C. After the reaction is completed, the reaction solution is cooled, and separated and purified by adding water and an organic solvent such as dichloromethane.

[0034] The third step of the reaction produces the product (P1), a metal salt of a strong acid (NaSbF6, KPF6, NaB(C6F5)4, R 1 The reaction mixture (P2) is washed with water and the reaction mixture (P3, P4, etc.) is subjected to salt exchange in a mixture of organic solvent (acetonitrile, chloroform, dichloromethane, DMF, etc.) and water. The reaction temperature is 0-30°C, and the reaction time is 10 minutes to 2 hours. After the reaction is completed, (P2) is obtained by washing with water.

[0035] The photoacid generator (P) of the present invention may be dissolved in advance in a solvent that does not inhibit the reaction, in order to facilitate dissolution in the resist material.

[0036] Examples of the solvent include carbonates (propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, diethyl carbonate, etc.), esters (ethyl acetate, ethyl lactate, β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc.), ethers (ethylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol dimethyl ether, triethylene glycol diethyl ether, tripropylene glycol dibutyl ether, etc.), and ether esters (ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, etc.).

[0037] When a solvent is used, the proportion of the solvent used is preferably 15 to 1000 parts by weight, more preferably 30 to 500 parts by weight, based on 100 parts by weight of the photoacid generator (P) of the present invention.

[0038] The photolithography resin composition (Q) of the present invention contains the selenonium salt represented by formula (1) as an essential component, and therefore, by performing irradiation with actinic rays such as ultraviolet rays and post-exposure baking (PEB), the solubility in a developer of an exposed area and an unexposed area becomes different. The selenonium salt can be used alone or in combination of two or more kinds. Examples of the resin composition for photolithography (Q) include a mixture of a negative-type chemically amplified resin (QN) and a photoacid generator (P); and a mixture of a positive-type chemically amplified resin (QP) and a photoacid generator (P).

[0039] The negative-type chemically amplified resin (QN) is composed of a phenolic hydroxyl group-containing resin (QN1) and a crosslinker (QN2).

[0040] The phenolic hydroxyl group-containing resin (QN1) is not particularly limited as long as it is a resin containing a phenolic hydroxyl group, and for example, novolac resin, polyhydroxystyrene, copolymer of hydroxystyrene, copolymer of hydroxystyrene and styrene, copolymer of hydroxystyrene, copolymer of styrene and (meth)acrylic acid derivative, phenol-xylylene glycol condensation resin, cresol-xylylene glycol condensation resin, polyimide containing a phenolic hydroxyl group, polyamic acid containing a phenolic hydroxyl group, phenol-dicyclopentadiene condensation resin are used. Among these, novolac resin, polyhydroxystyrene, copolymer of hydroxystyrene, copolymer of hydroxystyrene and styrene, copolymer of hydroxystyrene, copolymer of styrene and (meth)acrylic acid derivative, phenol-xylylene glycol condensation resin are preferred. It should be noted that these phenolic hydroxyl group-containing resins (QN1) may be used alone or in combination of two or more.

[0041] The novolak resin can be obtained, for example, by condensing a phenol with an aldehyde in the presence of a catalyst. Examples of the phenols include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, catechol, resorcinol, pyrogallol, 1-naphthol, and 2-naphthol. Examples of the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

[0042] Specific examples of the novolak resin include phenol / formaldehyde condensed novolak resin, cresol / formaldehyde condensed novolak resin, and phenol-naphthol / formaldehyde condensed novolak resin.

[0043] The phenolic hydroxyl group-containing resin (QN1) may contain a phenolic low molecular weight compound as a part of its components. Examples of the phenolic low molecular weight compound include 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, tris(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, tris(4-hydroxyphenyl)ethane, 1,3-bis[1-(4-hydroxyphenyl)-1-methylethyl]benzene, 1,4-bis[1-(4-hydroxyphenyl)-1-methylethyl]benzene, 4,6-bis[1-(4-hydroxyphenyl)-1-methylethyl]-1,3-dihydroxybenzene, 1,1-bis(4-hydroxyphenyl)-1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, and 4,4'-{1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene}bisphenol. These low molecular weight phenolic compounds may be used alone or in combination of two or more.

[0044] The content of this phenolic low molecular weight compound in the phenolic hydroxyl group-containing resin (QN1) is preferably 40% by weight or less, and more preferably 1 to 30% by weight, when the phenolic hydroxyl group-containing resin (QN1) is taken as 100% by weight.

[0045] The weight average molecular weight of the phenolic hydroxyl group-containing resin (QN1) is preferably 2000 or more, more preferably 2000 to 20,000, from the viewpoints of the resolution, thermal shock resistance, heat resistance, film remaining rate, etc. of the resulting insulating film. The content of the phenolic hydroxyl group-containing resin (QN1) in the negative-type chemically amplified resin (QN) is preferably 30 to 90% by weight, and more preferably 40 to 80% by weight, when the total weight of the composition excluding the solvent is taken as 100% by weight. When the content of the phenolic hydroxyl group-containing resin (QN1) is 30 to 90% by weight, this is preferable because the film formed using the photosensitive insulating resin composition has sufficient developability with an alkaline aqueous solution.

[0046] The crosslinking agent (QN2) is not particularly limited as long as it is a compound that can crosslink the phenolic hydroxyl group-containing resin (QN1) with the strong acid generated from the photoacid generator (P).

[0047] Examples of the crosslinking agent (QN2) include bisphenol A-based epoxy compounds, bisphenol F-based epoxy compounds, bisphenol S-based epoxy compounds, novolac resin-based epoxy compounds, resol resin-based epoxy compounds, poly(hydroxystyrene)-based epoxy compounds, oxetane compounds, methylol group-containing melamine compounds, methylol group-containing benzoguanamine compounds, methylol group-containing urea compounds, methylol group-containing phenol compounds, alkoxyalkyl group-containing melamine compounds, alkoxyalkyl group-containing benzoguanamine compounds, alkoxyalkyl group-containing urea compounds, alkoxyalkyl group-containing phenol compounds, carboxymethyl group-containing melamine resins, carboxymethyl group-containing benzoguanamine resins, carboxymethyl group-containing urea resins, carboxymethyl group-containing phenol resins, carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, carboxymethyl group-containing urea compounds, and carboxymethyl group-containing phenol compounds.

[0048] Among these crosslinking agents (QN2), methylol group-containing phenol compounds, methoxymethyl group-containing melamine compounds, methoxymethyl group-containing phenol compounds, methoxymethyl group-containing glycoluril compounds, methoxymethyl group-containing urea compounds and acetoxymethyl group-containing phenol compounds are preferred, and methoxymethyl group-containing melamine compounds (e.g., hexamethoxymethylmelamine), methoxymethyl group-containing glycoluril compounds and methoxymethyl group-containing urea compounds are more preferred. Methoxymethyl group-containing melamine compounds are commercially available under the trade names CYMEL300, CYMEL301, CYMEL303, CYMEL305 (manufactured by Mitsui Cyanamid Co., Ltd.), methoxymethyl group-containing glycoluril compounds are commercially available under the trade names CYMEL1174 (manufactured by Mitsui Cyanamid Co., Ltd.), and methoxymethyl group-containing urea compounds are commercially available under the trade names MX290 (manufactured by Sanwa Chemical Co., Ltd.).

[0049] The content of the crosslinking agent (QN2) is usually 5 to 60 mol %, preferably 10 to 50 mol %, and more preferably 15 to 40 mol %, based on the total acidic functional groups in the phenolic hydroxyl group-containing resin (QN1), from the viewpoints of reducing the residual film rate, preventing pattern meandering and swelling, and developing property.

[0050] Positive-type chemically amplified resins (QP) include protecting group-introduced resins (QP2) in which some or all of the hydrogen atoms of the acidic functional groups in an alkali-soluble resin (QP1) containing one or more acidic functional groups such as a phenolic hydroxyl group, a carboxyl group, or a sulfonyl group are substituted with acid-dissociable groups. The acid-dissociable group is a group that can dissociate in the presence of a strong acid generated from the photoacid generator (P). The protecting group-introduced resin (QP2) itself is insoluble or poorly soluble in alkali.

[0051] Examples of the alkali-soluble resin (QP1) include a phenolic hydroxyl group-containing resin (QP11), a carboxyl group-containing resin (QP12), and a sulfonic acid group-containing resin (QP13). As the phenolic hydroxyl group-containing resin (QP11), the same resin as the above hydroxyl group-containing resin (QN1) can be used.

[0052] The carboxyl group-containing resin (QP12) is not particularly limited as long as it is a polymer having a carboxyl group, and can be obtained, for example, by vinyl polymerization of a carboxyl group-containing vinyl monomer (Ba) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb).

[0053] Examples of the carboxyl group-containing vinyl monomer (Ba) include unsaturated monocarboxylic acids [(meth)acrylic acid, crotonic acid, cinnamic acid, etc.], unsaturated polyvalent (divalent to tetravalent) carboxylic acids [maleic acid (anhydride), itaconic acid, fumaric acid, citraconic acid, etc.], unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) esters [maleic acid monoalkyl esters, fumaric acid monoalkyl esters, citraconic acid monoalkyl esters, etc.], and salts thereof [alkali metal salts (sodium salts, potassium salts, etc.), alkaline earth metal salts (calcium salts, magnesium salts, etc.), amine salts, ammonium salts, etc.]. Among these, from the viewpoints of polymerizability and availability, unsaturated monocarboxylic acids are preferred, and (meth)acrylic acid is more preferred.

[0054] Examples of the hydrophobic group-containing vinyl monomer (Bb) include (meth)acrylic acid esters (Bb1) and aromatic hydrocarbon monomers (Bb2).

[0055] Examples of the (meth)acrylic acid ester (Bb1) include alkyl (meth)acrylates having an alkyl group of 1 to 20 carbon atoms [methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.] and alicyclic group-containing (meth)acrylates [dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, etc.].

[0056] Examples of the aromatic hydrocarbon monomer (Bb2) include hydrocarbon monomers having a styrene skeleton [styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, benzylstyrene, and the like] and vinylnaphthalene.

[0057] The molar ratio of monomers (Ba) / (Bb) charged in the carboxyl group-containing resin (QP12) is usually 10-100 / 0-90, and from the viewpoint of developability, is preferably 10-80 / 20-90, and more preferably 25-85 / 15-75.

[0058] The sulfonic acid group-containing resin (QP13) is not particularly limited as long as it is a polymer having a sulfonic acid group, and can be obtained, for example, by vinyl polymerization of a sulfonic acid group-containing vinyl monomer (Bc) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb). As the hydrophobic group-containing vinyl monomer (Bb), the same ones as those mentioned above can be used.

[0059] Examples of the sulfonic acid group-containing vinyl monomer (Bc) include vinyl sulfonic acid, (meth)allyl sulfonic acid, styrene sulfonic acid, α-methylstyrene sulfonic acid, 2-(meth)acryloylamide-2-methylpropane sulfonic acid, and salts thereof. Examples of the salts include alkali metal (sodium, potassium, etc.) salts, alkaline earth metal (calcium, magnesium, etc.) salts, primary to tertiary amine salts, ammonium salts, and quaternary ammonium salts.

[0060] In the sulfonic acid group-containing resin (QP13), the molar ratio of charged monomers (Bc) / (Bb) is usually 10-100 / 0-90, and from the viewpoint of developability, is preferably 10-80 / 20-90, and more preferably 25-85 / 15-75.

[0061] The HLB value of the alkali-soluble resin (QP1) varies depending on the resin skeleton of the alkali-soluble resin (QP1), but is preferably from 4 to 19, more preferably from 5 to 18, and particularly preferably from 6 to 17. When the HLB value is 4 or more, the developability is further improved during development, and when it is 19 or less, the water resistance of the cured product is further improved.

[0062] In addition, the HLB value in the present invention is the HLB value determined by the Oda method, which is the hydrophilic-hydrophobic balance value and can be calculated from the ratio of the organic value and the inorganic value of the organic compound. <Evaluation method of HLB> HLB ≒ 10 × inorganic property / organic property In addition, the inorganic value and the organic value are described in detail on page 501 of the literature "Synthesis and Application of Surfactants" (published by Makino Shoten, written by Oda and Teramura); or on page 198 of "New Introduction to Surfactants" (written by Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.).

[0063] Examples of the acid dissociable group in the protecting group-introduced resin (QP2) include a substituted methyl group, a 1-substituted ethyl group, a 1-branched alkyl group, a silyl group, a germyl group, an alkoxycarbonyl group, an acyl group, and a cyclic acid dissociable group. These may be used alone or in combination of two or more.

[0064] Examples of the substituted methyl group include a methoxymethyl group, a methylthiomethyl group, an ethoxymethyl group, an ethylthiomethyl group, a methoxyethoxymethyl group, a benzyloxymethyl group, a benzylthiomethyl group, a phenacyl group, a bromophenacyl group, a methoxyphenacyl group, a methylthiophenacyl group, an α-methylphenacyl group, a cyclopropylmethyl group, a benzyl group, a diphenylmethyl group, a triphenylmethyl group, a bromobenzyl group, a nitrobenzyl group, a methoxybenzyl group, a methylthiobenzyl group, an ethoxybenzyl group, an ethylthiobenzyl group, a piperonyl group, a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group, an n-propoxycarbonylmethyl group, an i-propoxycarbonylmethyl group, an n-butoxycarbonylmethyl group, and a tert-butoxycarbonylmethyl group.

[0065] Examples of the 1-substituted ethyl group include a 1-methoxyethyl group, a 1-methylthioethyl group, a 1,1-dimethoxyethyl group, a 1-ethoxyethyl group, a 1-ethylthioethyl group, a 1,1-diethoxyethyl group, a 1-ethoxypropyl group, a 1-propoxyethyl group, a 1-cyclohexyloxyethyl group, a 1-phenoxyethyl group, a 1-phenylthioethyl group, a 1,1-diphenoxyethyl group, a 1-benzyloxyethyl group, a 1-benzylthioethyl group, a 1-cyclopropylethyl group, a 1-phenylethyl group, a 1,1-diphenylethyl group, a 1-methoxycarbonylethyl group, a 1-ethoxycarbonylethyl group, a 1-n-propoxycarbonylethyl group, a 1-isopropoxycarbonylethyl group, a 1-n-butoxycarbonylethyl group, and a 1-tert-butoxycarbonylethyl group.

[0066] Examples of the 1-branched alkyl group include an isopropyl group, a sec-butyl group, a tert-butyl group, a 1,1-dimethylpropyl group, a 1-methylbutyl group, and a 1,1-dimethylbutyl group.

[0067] Examples of the silyl group include tricarbylsilyl groups such as a trimethylsilyl group, an ethyldimethylsilyl group, a diethylmethylsilyl group, a triethylsilyl group, an isopropyldimethylsilyl group, a diisopropylmethylsilyl group, a triisopropylsilyl group, a tert-butyldimethylsilyl group, a di-tert-butylmethylsilyl group, a tri-tert-butylsilyl group, a dimethylphenylsilyl group, a methyldiphenylsilyl group, and a triphenylsilyl group.

[0068] Examples of the germyl group include tricarbylgermyl groups such as a trimethylgermyl group, an ethyldimethylgermyl group, a methyldiethylgermyl group, a triethylgermyl group, an isopropyldimethylgermyl group, a methyldiisopropylgermyl group, a triisopropylgermyl group, a tert-butyldimethylgermyl group, a di-tert-butylmethylgermyl group, a tri-tert-butylgermyl group, a dimethylphenylgermyl group, a methyldiphenylgermyl group, and a triphenylgermyl group.

[0069] Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropoxycarbonyl group, and a tert-butoxycarbonyl group.

[0070] Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, a heptanoyl group, a hexanoyl group, a valeryl group, a pivaloyl group, an isovaleryl group, a lauroyl group, a myristoyl group, a palmitoyl group, a stearoyl group, an oxalyl group, a malonyl group, a succinyl group, a glutaryl group, an adipoyl group, a piperoyl group, a suberoyl group, an azelaoyl group, a sebacoyl group, an acryloyl group, a propioloyl group, Examples of the alkyl group include methacryloyl, crotonoyl, oleoyl, maleoyl, fumaroyl, mesaconoyl, campholoyl, benzoyl, phthaloyl, isophthaloyl, terephthaloyl, naphthoyl, toluoyl, hydroatropoyl, atropoyl, cinnamoyl, furoyl, thenoyl, nicotinoyl, isonicotinoyl, p-toluenesulfonyl, and mesyl groups.

[0071] Examples of cyclic acid-dissociable groups include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexenyl group, a 4-methoxycyclohexyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a tetrahydrothiopyranyl group, a tetrahydrothiofuranyl group, a 3-bromotetrahydropyranyl group, a 4-methoxytetrahydropyranyl group, a 4-methoxytetrahydrothiopyranyl group, and a 3-tetrahydrothiophene-1,1-dioxide group.

[0072] Of these acid-dissociable groups, tert-butyl, benzyl, 1-methoxyethyl, 1-ethoxyethyl, trimethylsilyl, tert-butoxycarbonyl, tert-butoxycarbonylmethyl, tetrahydropyranyl, tetrahydrofuranyl, tetrahydrothiopyranyl and tetrahydrothiofuranyl groups are preferred.

[0073] The introduction rate of the acid-dissociable group in the protecting group-introduced resin (QP2) {the ratio of the number of acid-dissociable groups to the total number of unprotected acidic functional groups and acid-dissociable groups in the protecting group-introduced resin (QP2)} cannot be generally defined depending on the type of acid-dissociable group and the alkali-soluble resin into which the group is introduced, but is preferably 10 to 100%, more preferably 15 to 100%.

[0074] The weight average molecular weight (hereinafter referred to as "Mw") of the protecting group-introduced resin (QP2) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably from 1,000 to 150,000, and more preferably from 3,000 to 100,000.

[0075] The ratio (Mw / Mn) of the Mw of the protecting group-introduced resin (QP2) to the polystyrene-equivalent number average molecular weight (hereinafter referred to as "Mn") measured by gel permeation chromatography (GPC) is usually 1 to 10, and preferably 1 to 5.

[0076] The content of the photoacid generator (P) based on the weight of the solid content of the resin composition for photography (Q) is preferably from 0.001 to 20% by weight, more preferably from 0.01 to 15% by weight, and particularly preferably from 0.05 to 7% by weight. If it is 0.001% by weight or more, the sensitivity to ultraviolet light can be more favorably exhibited, and if it is 20% by weight or less, the physical properties of the portion insoluble in an alkaline developer can be more favorably exhibited.

[0077] A resist using the resin composition for photography (Q) of the present invention can be formed, for example, by applying a solution of the resin dissolved in a predetermined organic solvent (or dissolved and dispersed when inorganic fine particles are contained) to a substrate by a known method such as spin coating, curtain coating, roll coating, spray coating, or screen printing, and then drying the solvent by heating or blowing hot air.

[0078] The organic solvent for dissolving the resin composition for photography (Q) is not particularly limited as long as it can dissolve the resin composition and can adjust the physical properties (such as viscosity) of the resin solution so that it can be applied to spin coating, etc. For example, known solvents such as N-methylpyrrolidone, N,N-dimethylformamide, dimethylsulfoxide, toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, acetone, and xylene can be used. Among these solvents, from the viewpoint of drying temperature and the like, those having a boiling point of 200°C or less (toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, acetone, and xylene) are preferred, and they may be used alone or in combination of two or more kinds. When an organic solvent is used, the amount of the solvent is not particularly limited, but is usually preferably 30 to 1,000% by weight, more preferably 40 to 900% by weight, and particularly preferably 50 to 800% by weight, based on the weight of the solid content of the resin composition for photography (Q).

[0079] The drying conditions for the resin solution after coating vary depending on the solvent used, but are preferably carried out at 50 to 200°C for 2 to 30 minutes, and are appropriately determined based on the amount of residual solvent (wt%) in the resin composition for photography (Q) after drying.

[0080] After forming a resist on the substrate, the resist is irradiated with light in the shape of a wiring pattern, followed by post-exposure baking (PEB) and alkaline development to form the wiring pattern.

[0081] As a method of irradiating the resist with light, a method of exposing the resist to active light through a photomask having a wiring pattern can be mentioned. There are no particular limitations as long as the photoacid generator (P) in the resin composition for photography (Q) can be decomposed. Examples of actinic rays include extreme ultraviolet rays (EUV), electron beams (EB), low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, extra-high pressure mercury lamps, xenon lamps, metal halogen lamps, electron beam irradiation devices, X-ray irradiation devices, lasers (argon lasers, dye lasers, nitrogen lasers, LEDs, helium cadmium lasers, etc.), etc. Of these, extreme ultraviolet rays (EUV) and electron beams (EB) are most preferable for achieving the effects of the present invention.

[0082] The temperature of the post-exposure bake (PEB) is usually 40 to 200° C., preferably 50 to 190° C., and more preferably 60 to 180° C. If the temperature is lower than 40° C., the deprotection reaction or crosslinking reaction cannot proceed sufficiently, and the difference in solubility between the UV-irradiated area and the UV-unirradiated area is insufficient, making it impossible to form a pattern. If the temperature is higher than 200° C., there is a problem that the productivity decreases. The heating time is usually 0.5 to 120 minutes. If it is less than 0.5 minutes, it is difficult to control the time and temperature, whereas if it is more than 120 minutes, there is a problem that the productivity decreases.

[0083] The alkaline development method includes a method of dissolving and removing the wiring pattern shape using an alkaline developer. The alkaline developer is not particularly limited as long as it can cause a difference in solubility between the ultraviolet irradiated part and the ultraviolet unirradiated part of the resin composition for photography (Q). The alkaline developer includes an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydrogen carbonate, and an aqueous solution of tetramethylammonium salt. These alkaline developers may contain water-soluble organic solvents, such as methanol, ethanol, isopropyl alcohol, tetrahydrofuran, and N-methylpyrrolidone.

[0084] The developing method includes a dip method, a shower method, and a spray method using an alkaline developer, with the spray method being preferred. The temperature of the developer used is preferably 25 to 40° C. The development time is appropriately determined depending on the thickness of the resist. EXAMPLES

[0085] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. In the following, % means % by weight, and parts means parts by weight, unless otherwise specified.

[0086] <Production Example 1> <Synthesis of (2-methylphenyl)phenyl selenide> 1.0 part of 2-methylphenyl bromide, 1.1 parts of phenylselenol, and 0.5 parts of potassium hydroxide were dispersed in 10 parts of dimethylacetamide and stirred at 120°C for 5 hours. After cooling to room temperature, 30 parts of water and 30 parts of dichloromethane were added, the organic layer was collected, and the solvent was removed under reduced pressure to obtain a crude product. This crude product was recrystallized with 20 parts of cyclohexane to obtain 0.6 parts of (2-methylphenyl)phenyl selenide.

[0087] <Production Example 2> <Synthesis of (3,5-dimethylphenyl)phenyl selenide> 0.5 part of (3,5-dimethylphenyl)phenyl selenide was obtained in the same manner as in Production Example 1, except that 1.0 part of 2-methylphenyl bromide was changed to 1.0 part of 3,5-dimethylphenyl bromide.

[0088] <Production Example 3> <Synthesis of (4-methylphenyl)phenyl selenide> 0.6 part of (4-methylphenyl)phenyl selenide was obtained in the same manner as in Production Example 1, except that 1.0 part of 2-methylphenyl bromide was changed to 1.0 part of 4-methylphenyl bromide.

[0089] <Production Example 4> <Synthesis of (3-trifluoromethylphenyl)phenyl selenide> The same procedure as in Production Example 1 was repeated except that 1.0 part of 2-methylphenyl bromide was changed to 1.2 parts of 3-trifluoromethylphenyl bromide, to obtain 0.5 part of (4-methylphenyl)phenyl selenide.

[0090] <Production Example 5> <Synthesis of (3-trifluoromethylphenyl)phenyl selenoxide> 1.0 part of (3-trifluoromethylphenyl)phenyl selenide obtained in Production Example 4 was dissolved in 18.0 parts of acetonitrile, 0.8 parts of sodium hypochlorite pentahydrate and 0.1 parts of tetrabutylammonium hydrogen sulfate were added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was poured into water, and the precipitate was filtered off to obtain a white solid. The white solid was washed with water and dried to obtain 0.8 parts of (3-trifluoromethylphenyl)phenyl selenoxide.

[0091] <Example 1> <Synthesis of triphenylselenonium triflate (P-1-1)> 1.0 part of diphenyl selenide was dispersed in 20 parts of chlorobenzene, and 1.3 parts of diphenyl iodonium triflate was added and stirred at 120°C for 17 hours. The reaction solution was poured into 20 parts of water, and after cooling, 20 parts of methanol was added to extract and recover the aqueous layer. Next, 10 parts of dichloromethane was added to the aqueous layer to extract and recover the organic layer, and the solvent was dried under reduced pressure to obtain 0.5 parts of triphenyl selenonium triflate (P-1-1).

[0092] <Example 2> <Synthesis of (4-bromophenyl)diphenylselenonium triflate (P-1-2)> 0.4 parts of (4-bromophenyl)diphenylselenonium triflate (P-1-2) was obtained in the same manner as in Example 1, except that 1.3 parts of diphenyliodonium triflate was changed to 1.7 parts of bis(4-bromophenyl)iodonium triflate and the reaction time was changed to 48 hours.

[0093] <Example 3> <Synthesis of (4-tert-butylphenyl)diphenylselenonium triflate (P-1-3)> 0.5 parts of (4-tert-butylphenyl)diphenylselenonium triflate (P-1-3) was obtained in the same manner as in Example 1, except that 1.3 parts of diphenyliodonium triflate was changed to 1.5 parts of bis(4-tert-butylphenyl)iodonium triflate.

[0094] <Example 4> <Synthesis of (4-fluorophenyl)diphenylselenonium triflate (P-1-4)> The same procedure as in Example 1 was repeated except that 1.3 parts of diphenyliodonium triflate was replaced with 1.4 parts of bis(4-fluorophenyl)iodonium triflate, the reaction time was 48 hours, and the reaction solvent was changed to N,N-dimethylacetamide, to obtain 0.3 parts of (4-fluorophenyl)diphenylselenonium triflate (P-1-4).

[0095] <Example 5> <Synthesis of (4-methoxyphenyl)diphenylselenonium triflate (P-1-5)> 0.5 parts of (4-methoxyphenyl)diphenylselenonium triflate (P-1-5) was obtained in the same manner as in Example 1, except that 1.3 parts of diphenyliodonium triflate was changed to 1.5 parts of bis(4-methoxyphenyl)iodonium triflate.

[0096] <Example 6> <Synthesis of (3-trifluoromethylphenyl)diphenylselenonium triflate (P-1-6)> 1.0 part of the (3-trifluoromethylphenyl)phenyl selenoxide obtained in Production Example 5 was dissolved in a mixed solvent of 20 parts of dichloromethane and 20 parts of benzene, and 1.2 parts of trifluoromethanesulfonic anhydride was added dropwise at 0° C. or lower. The reaction mixture was quenched by pouring it into 50 parts of water, and extraction was carried out by adding 30 parts of methanol. Further, extraction was performed three times with 30 parts of water and 20 parts of methanol. The extracted water-methanol layer was washed twice with 20 parts of toluene, and extracted three times with 20 parts of dichloromethane. The dichloromethane layer was poured into 200 parts of TBME (tert-butyl methyl ether), and the precipitated viscous material was dried under reduced pressure to obtain 0.2 parts of (3-trifluoromethylphenyl)diphenylselenonium triflate (P-1-6).

[0097] <Example 7> <Synthesis of (2-methylphenyl)diphenylselenonium nonaflate (P-2-1)> The same procedure as in Example 1 was repeated except that 1.0 part of diphenyl selenide was replaced with 1.0 part of (2-methylphenyl)phenyl selenide obtained in Production Example 1, to obtain 0.5 part of product. 0.5 parts of the obtained (2-methylphenyl)diphenylselenonium triflate was dissolved in 10 parts of dichloromethane, and 10 parts of water and 0.4 parts of potassium nonafluorobutanesulfonate were added and stirred for 30 minutes. The water layer was removed, and 10 parts of water was added and washed three times. The dichloromethane layer was dried under reduced pressure to obtain 0.6 parts of (2-methylphenyl)diphenylselenonium nonaflate (P-2-1).

[0098] <Example 8> <Synthesis of (3,5-methylphenyl)diphenylselenonium nonaflate (P-2-2)> 0.6 part of (3,5-methylphenyl)diphenylselenonium triflate was obtained in the same manner as in Example 1, except that 1.0 part of diphenyl selenide was replaced with 1.0 part of (3,5-methylphenyl)phenyl selenide obtained in Production Example 2. 0.6 parts of the obtained (3,5-methylphenyl)diphenylselenonium triflate was dissolved in 12 parts of dichloromethane, and 10 parts of water and 0.5 parts of potassium nonafluorobutanesulfonate were added and stirred for 30 minutes. The water layer was removed, and 10 parts of water was added and washed three times. The dichloromethane layer was dried under reduced pressure to obtain 0.7 parts of (3,5-methylphenyl)diphenylselenonium nonaflate (P-2-2).

[0099] <Example 9> <Synthesis of (4-tert-butylphenyl)(4-methylphenyl)phenylselenonium nonaflate (P-2-3)> 0.5 parts of (4-tert-butylphenyl)(4-methylphenyl)phenylselenonium triflate was obtained in the same manner as in Example 1, except that 1.0 part of diphenyl selenide was replaced with 1.0 part of (4-methylphenyl)phenyl selenide obtained in Production Example 3 and 1.3 parts of diphenyliodonium triflate were replaced with 1.5 parts of bis(4-tert-butylphenyl)iodonium triflate. 0.5 parts of the obtained (4-tert-butylphenyl) (4-methylphenyl) phenylselenonium triflate was dissolved in 12 parts of dichloromethane, and 10 parts of water and 0.4 parts of potassium nonafluorobutanesulfonate were added and stirred for 30 minutes. The water layer was removed, and 10 parts of water was added and washed three times. The dichloromethane layer was dried under reduced pressure to obtain 0.6 parts of (4-tert-butylphenyl) (4-methylphenyl) phenylselenonium nonaflate (P-2-3).

[0100] <Example 10> <Synthesis of triphenylselenonium tetrakispentafluorophenylborate (P-2-4)> 1.0 part of triphenylselenonium triflate (P-1-1) obtained in Example 1 was dissolved in 20 parts of dichloromethane, and 2.2 parts of lithium tetrakispentafluorophenylborate-ethyl ether complex (TCI Corporation) and 10 parts of water were added and stirred for 1 hour. After removing the water layer, 10 parts of water and 5 parts of methanol were added and washed with water three times. The dichloromethane layer was concentrated under reduced pressure, and 20 parts of methanol were added and concentrated again. The concentrated methanol layer was poured into 50 parts of water to obtain a precipitate, which was filtered and dried under reduced pressure to obtain 1.8 parts of triphenylselenonium tetrakispentafluorophenylborate (P-2-4).

[0101] <Example 11> <Synthesis of triphenylselenonium tris(trifluoromethanesulfonyl)methanide (P-2-5)> 1.0 part of triphenylselenonium triflate (P-1-1) obtained in Example 1 was dissolved in 20 parts of dichloromethane, and 1.1 parts of potassium tris(trifluoromethanesulfonyl)methanide (TCI Corporation) and 20 parts of water were added and stirred for 1 hour. The water layer was removed, and 20 parts of water were added for washing. The dichloromethane layer was concentrated under reduced pressure and poured into 150 parts of TBME to obtain a precipitate, which was filtered and dried under reduced pressure to obtain 1.3 parts of triphenylselenonium tris(trifluoromethanesulfonyl)methanide (P-2-5).

[0102] The structures of the photoacid generators (P-1-1) to (P-2-5) obtained in Examples 1 to 11 are shown below.

[0103] [ka]

[0104] <Comparative Example 1> <Synthesis of ionic photoacid generator (P'-1)> Triphenylsulfonium triflate (manufactured by Fuji Film Wako Chemical Co., Ltd.) was used as is.

[0105] <Comparative Example 2> <Synthesis of ionic photoacid generator (P'-2)> According to Example 1 of Patent No. 4934306, (4-phenylthiophenyl)diphenylsulfonium triflate (P'-2) was obtained.

[0106] [ka]

[0107] <Comparative Example 3> <Synthesis of ionic photoacid generator (P'-3)> According to Example 6 of JP 2014-234348, (3-trifluoromethylphenyl)diphenylsulfonium triflate (P'-3) was obtained.

[0108] [ka]

[0109] <Comparative Example 4> In the same manner as in Example 1 of JP 2014-234348 A, 4-chlorobromobenzene and diphenyl sulfoxide were reacted and purified to obtain 4-chlorophenyldiphenylsulfonium triflate. 5 parts of the obtained 4-chlorophenyldiphenylsulfonium triflate was dissolved in 40 parts of acetonitrile, 2 parts of phenylselenol and 2.6 parts of a 50% aqueous potassium hydroxide solution were added, and the mixture was heated at 50° C. for 10 hours. To the reaction liquid, 50 parts of dichloromethane and 50 parts of water were added, and the precipitate was removed by filtration. 120 parts of chloroform and 50 parts of toluene were added to the filtrate for liquid separation and washing, and the chloroform layer was concentrated under reduced pressure to obtain (4-phenylselenophenyl)diphenylsulfonium triflate (P'-4).

[0110] [ka]

[0111] <Comparative Example 5> 5 parts of the triphenylsulfonium triflate used in Comparative Example 1 was dissolved in 50 parts of dichloromethane, and 6 parts of potassium tris(trifluoromethanesulfonyl)methanide (TCI Corporation) and 50 parts of water were added and stirred for 1 hour. The water layer was removed, and 30 parts of water was added for washing. The dichloromethane layer was concentrated under reduced pressure and poured into 150 parts of TBME to obtain a precipitate, which was filtered and dried under reduced pressure to obtain triphenylsulfonium tris(trifluoromethanesulfonyl)methanide (P'-5).

[0112] [ka]

[0113] <Sensitivity evaluation> The sensitivity was measured and evaluated by the following method. (Preparation of sample solution) The photoacid generator (P) of the present invention was mixed with a 20-fold weight ratio of a photosensitive resin (copolymer of polyhydroxystyrene and t-butoxyacrylate) and dissolved in propylene glycol monomethyl ether acetate (PGMEA) so that the molar concentration of the photoacid generator was 2.0 mM.

[0114] (Film forming) The sample solution was spread on a substrate treated with hexamethyldisilazane (HMDS) using a spin coater, and the solvent was removed by heating at 130°C for 60 seconds to form a film with a thickness of approximately 50 nm.

[0115] (exposure) The film-formed sample was placed in BL-3 at the New SUBARU Synchrotron Radiation Facility of the University of Hyogo and irradiated with 13.5 nm synchrotron radiation.

[0116] (developing) After exposure, the sample was heated at 110° C. for 90 seconds, developed with a 2.38% aqueous solution of tetramethylammonium hydroxide for 60 seconds, and rinsed with running water for 30 seconds.

[0117] (sensitivity) The exposed sample was measured under a microscope to determine the minimum exposure dose required for complete removal of the resist film (film penetration sensitivity). In order to eliminate the influence of daily variations in synchrotron radiation, the sensitivity of Comparative Example P'-1 measured on the same day was taken as 1, and the relative sensitivity was evaluated according to the following criteria. When the sensitivity of Comparative Example P'-1 is taken as 1, the sensitivity is 1 or more: × When the sensitivity of Comparative Example P'-1 is taken as 1, sensitivity is less than 1, 0.75 or more: △ When the sensitivity of Comparative Example P'-1 is taken as 1, sensitivity is less than 0.75 and 0.5 or more: ◯ When the sensitivity of Comparative Example P'-1 is taken as 1, sensitivity is less than 0.5: ◎

[0118] The sensitivity of the photoacid generators (P-1-1) to (P-2-5) prepared in Examples 1 to 11 and the photoacid generators (P'-1) to (P'-5) prepared in Comparative Examples 1 to 5 was measured by the method described above. The results are shown in Table 1.

[0119] [Table 1]

[0120] As shown in Table 1, the photoacid generator (P) of the selenonium salt of the present invention exhibits higher sensitivity to EUV than that of the conventional sulfonium salt. [Industrial Applicability]

[0121] The photoacid generator (P) of the present invention has high sensitivity to EUV or EB, and is therefore useful as a photolithography material for microfabrication, typically in the production of semiconductors.

Claims

1. A photoacid generator (P) comprising a selenonium salt represented by the following general formula (1): 【Chemistry 1】 [In formula (1), X1, X2, and X3 each independently represent a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms (the hydrogen atoms of these alkyl and aryl groups may be partially or completely substituted with fluorine atoms), y1, y2, and y3 each independently represent an integer of 0 to 5, and A represents a sulfonate anion.]

2. In the general formula (1), X1, X2 and X3 are F, CF ３ , C ２ F ５ , C ３ F ７ , C ４ F ９ , or C ６ F ５ The photoacid generator (P) according to claim 1 ,

3. The photoacid generator (P) according to claim 1 or 2, which is intended for extreme ultraviolet (EUV) or electron beam (EB).

4. A resin composition for photolithography (Q), comprising the photoacid generator (P) according to any one of claims 1 to 3.

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