JP7657062B2 - Photoacid generator and resin composition for photolithography - Google Patents

Description

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 (EUV) or electron beam (EB), and a resin composition for photolithography containing the same.

Photoacid generators are a general term for compounds that decompose and generate acid when irradiated with active energy rays such as light, electron beams, or X-rays. The acid generated by irradiation with active energy rays is used as the active species in various reactions such as polymerization, crosslinking, and deprotection reactions. Specific examples include the 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 protective groups have been introduced into alkali-soluble resins.

Photolithography technology is widely used to manufacture electronic components and form semiconductor elements, and chemically amplified resists that utilize acid generated from photoacid generators are widely used. Semiconductor elements are mass-produced using KrF excimer lasers and ArF excimer lasers as exposure light sources, but in recent years, with the need for finer patterns, short-wavelength (high-energy) EUV (extreme ultraviolet), EB (electron beam), X-rays, and other light sources are also being considered.

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 generally used in chemically amplified resists for KrF excimer lasers and ArF excimer lasers, are used in EUV and EB lithography, their photosensitivity is insufficient, and therefore highly sensitive photoacid generators specialized for EUV, EB, X-rays, etc. have been developed.
As photoacid generators for EUV resists, a photoacid generator having a characteristic anion (Patent Document 1) and a photoacid generator having an adjusted cation structure (Patent Documents 2, 3, and 4) have been proposed, but all of them have insufficient sensitivity to EUV.

JP 2009-237176 A Patent No. 5678747 JP 2014-234348 A JP 2019-201404 A

In the above-mentioned 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 which contains the above photoacid generator.

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) containing a selenonium salt represented by the following general formula (1); and a resin composition for photolithography (Q) containing the photoacid generator (P).

[In formula (1), X1, X2, and X3 are each independently a halogen atom, a hydroxyl 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 (the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, and arylseleno groups may be partially or completely substituted with fluorine atoms), y1, y2, and y3 are each independently an integer between 0 and 5, and A is a monovalent anion.]

The photoacid generator (P) of the present invention has high EUV absorption and is easily decomposable 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 easily decompose when irradiated with EUV or EB, and generate various acids including strong acids such as sulfonic acid. Furthermore, the sensitivity, solubility, and storage stability can be controlled by introducing substituents into X1 to X3.

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

[In formula (1), X1, X2, and X3 are each independently a halogen atom, a hydroxyl 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 (the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, and arylseleno groups may be partially or completely substituted with fluorine atoms), y1, y2, and y3 are each independently an integer between 0 and 5, and A is a monovalent anion.]

In formula (1), X1, X2, and X3 are each independently a halogen atom, a hydroxyl 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 (the hydrogen atoms of these alkyl groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, and arylseleno groups may be partially or completely substituted with fluorine atoms).

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

Examples of alkyl groups 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.). In addition, some or all of the hydrogen atoms in these groups may be substituted with fluorine.

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

Examples of aryl groups having 6 to 14 carbon atoms include aryl groups such as phenyl, 1-naphthyl, 2-naphthyl, 1-azulenyl, anthracenyl, and phenanthrenyl. In addition, some or all of the hydrogen atoms in these groups may be substituted with fluorine.

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.

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.

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.

In formula (1), from the viewpoints of sensitivity, stability, and 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 (a part or all of the hydrogen atoms in these alkyl and aryl groups may be substituted with fluorine atoms) _{, and} more preferably F, _CF3 , _{C2F5 , C3F7} , _C4F9 , or _{C6F5 .}

In formula (1), y1, y2, and y3 are each independently an integer from 0 to 5. Preferably, they are an integer from 0 to 2.

In formula (1), A ⁻ represents a monovalent anion.
_Examples of monovalent anions include 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- , (} ^C4 F ₉ SO ₂ ) ₂ N ^-- and R ¹ SO ₃ ^-- .

Examples of the sulfonate anion represented by R ¹ SO ₃ ^- 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 anions represented by the following general formula (2):

[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 a part of the methylene chain may be substituted with -O-, -CO-, -COO-, -OCO-, -OCOO-, -S-, -SO- or -SO ₂ - group, and may form a bicyclo structure or a spiro structure), R ³ and R ⁴ each independently are 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 (some 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 -SO ₂ - group).]

From the viewpoints of sensitivity, roughness reduction, and ease of availability, ^A- is preferably a sulfonate anion represented by R ¹ SO ₃ ^- , and more preferably a trifluoromethanesulfonate anion (triflate), a nonafluorobutanesulfonate anion (nonaflate), or one represented by formula (2) in which R ³ and R ⁴ are a fluorine atom or a fluoroalkyl group having 1 to 4 carbon atoms.

The method for synthesizing the selenonium salt of the present invention is not particularly limited as long as it is possible to synthesize the target product, but for example, it can be produced by the production method described below.

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.

The base is not particularly limited as long as it can abstract a proton from SeH in the arylselenol, but _examples of the base include alkali metal hydroxides (KOH, NaOH, etc.), alkali metal salts of carbonate anions ( _K2CO3 , _Na2CO3 , _etc. ), organic bases (diazabicycloundecene, triethylamine, pyridine, etc.), and alkali metal hydrides (LiH, NaH, etc.).

The second stage reaction may be carried out immediately after the first stage reaction, or after isolating (and purifying, if necessary) the precursor selenide. The precursor selenide is mixed and stirred with an organic solvent (acetonitrile, dioxane, tetrahydrofuran, DMF, etc.), and this 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 complete, the reaction solution is cooled, and separated and purified by adding water and an organic solvent such as dichloromethane.

In the third step, the product (P1) and a metal salt of _a strong acid ( _NaSbF6 , _KPF6 , NaB( _C6F5 ) ₄ , ^R1SO3NBu4 , _etc. ) are exchanged in a mixture _of an 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 complete, the product is washed with water to obtain (P2).

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 into the resist material.

Examples of solvents 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.).

When a solvent is used, the ratio of the solvent used is preferably 15 to 1000 parts by weight, and more preferably 30 to 500 parts by weight, per 100 parts by weight of the photoacid generator (P) of the present invention.

Since the resin composition for photolithography (Q) of the present invention contains the selenonium salt represented by formula (1) as an essential component, the solubility in a developer of an exposed area and an unexposed area is differentiated by irradiation with actinic rays such as ultraviolet light and post-exposure baking (PEB). The selenonium salt may 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).

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

The phenolic hydroxyl group-containing resin (QN1) is not particularly limited as long as it contains a phenolic hydroxyl group, and examples thereof include 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, and phenol-dicyclopentadiene condensation resin. Among these, novolac resin, polyhydroxystyrene, copolymer of hydroxystyrene, copolymer of hydroxystyrene and styrene, copolymer of hydroxystyrene, copolymer of styrene and (meth)acrylic acid derivative, and phenol-xylylene glycol condensation resin are preferred. These phenolic hydroxyl group-containing resins (QN1) may be used alone or in combination of two or more.

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.

Specific examples of novolac resins include phenol/formaldehyde condensation novolac resin, cresol/formaldehyde condensation novolac resin, and phenol-naphthol/formaldehyde condensation novolac resin.

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.

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, assuming that the phenolic hydroxyl group-containing resin (QN1) is 100% by weight.

The weight average molecular weight of the phenolic hydroxyl group-containing resin (QN1) is preferably 2,000 or more, more preferably 2,000 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.

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).

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.

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 CYMEL 300, CYMEL 301, CYMEL 303, CYMEL 305 (manufactured by Mitsui Cyanamid Co., Ltd.), methoxymethyl group-containing glycoluril compounds are commercially available under the trade names CYMEL 1174 (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.).

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 properties.

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.

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.

There are no particular limitations on the carboxyl group-containing resin (QP12) as long as it is a polymer having a carboxyl group. For example, it can be obtained by vinyl polymerization of a carboxyl group-containing vinyl monomer (Ba) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb).

Examples of the carboxyl group-containing vinyl monomer (Ba) include unsaturated monocarboxylic acids [(meth)acrylic acid, crotonic acid, cinnamic acid, etc.], unsaturated polyvalent (di- 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.

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

Examples of (meth)acrylic acid esters (Bb1) include alkyl (meth)acrylates in which the alkyl group has 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.].

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

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

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 monomers as those mentioned above can be used.

Examples of the sulfonic acid group-containing vinyl monomer (Bc) include vinyl sulfonic acid, (meth)allylsulfonic acid, styrenesulfonic acid, α-methylstyrenesulfonic acid, 2-(meth)acryloylamide-2-methylpropanesulfonic 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.

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

The HLB value of the alkali-soluble resin (QP1) varies depending on the resin skeleton of the alkali-soluble resin (QP1), but is preferably in the range of 4-19, more preferably 5-18, and particularly preferably 6-17.
If the HLB value is 4 or more, the developability during development is better, and if it is 19 or less, the water resistance of the cured product is better.

The HLB value in the present invention is an HLB value according to the Oda method, which is a hydrophilic-hydrophobic balance value, and can be calculated from the ratio of the organic value to the inorganic value of an organic compound.
<HLB evaluation method>
HLB ≈ 10 × inorganicity/organicity. The inorganicity value and the organicity value are described in detail on page 501 of the literature "Synthesis of Surfactants and Their Applications" (published by Maki 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.).

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.

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

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

Examples of 1-branched alkyl groups include isopropyl, sec-butyl, tert-butyl, 1,1-dimethylpropyl, 1-methylbutyl, and 1,1-dimethylbutyl groups.

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

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

Examples of alkoxycarbonyl groups include methoxycarbonyl groups, ethoxycarbonyl groups, isopropoxycarbonyl groups, and tert-butoxycarbonyl groups.

Examples of acyl groups include acetyl, propionyl, butyryl, heptanoyl, hexanoyl, valeryl, pivaloyl, isovaleryl, lauroyl, myristoyl, palmitoyl, stearoyl, oxalyl, malonyl, succinyl, glutaryl, adipoyl, piperoyl, suberoyl, azelayl, sebacoyl, acryloyl, propioloyl, These 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.

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

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

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 determined 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%, and more preferably 15 to 100%.

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

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.

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 the content is 0.001% by weight or more, the sensitivity to ultraviolet light can be more favorably exhibited, and if the content is 20% by weight or less, the physical properties of the portion insoluble in an alkaline developer can be more favorably exhibited.

A resist using the resin composition for photography (Q) of the present invention can be formed, for example, by applying a resin solution dissolved in a specific organic solvent (or dissolved and dispersed if inorganic fine particles are included) to a substrate using 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.

The organic solvent in which the resin composition for photography (Q) is dissolved 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 blending 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).

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

After forming a resist on the substrate, the substrate is irradiated with light in the shape of a wiring pattern. After that, post-exposure bake (PEB) is performed, followed by alkaline development to form the wiring pattern.

The method of light irradiation includes a method of exposing the resist to active light through a photomask having a wiring pattern. The active light used for light irradiation is not particularly limited as long as it can decompose the photoacid generator (P) in the resin composition for photography (Q) of the present invention.
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.

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 less than 40° C., the deprotection reaction or crosslinking reaction cannot be sufficiently carried out, and the difference in solubility between the UV-irradiated portion and the UV-unirradiated portion 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 minute, it is difficult to control the time and temperature, whereas if it is more than 120 minutes, there is a problem that productivity decreases.

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 portion and the ultraviolet unirradiated portion of the resin composition for photography (Q).
Alkaline developers include aqueous solutions of sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate and tetramethylammonium salts.
These alkaline developers may contain water-soluble organic solvents, such as methanol, ethanol, isopropyl alcohol, tetrahydrofuran, and N-methylpyrrolidone.

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.

The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, % means % by weight and parts means parts by weight.

<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 the mixture was stirred at 120° C. for 5 hours. After cooling to room temperature, 30 parts of water and 30 parts of dichloromethane were added, and the organic layer was recovered, and the solvent was removed under reduced pressure to obtain a crude product. This crude product was recrystallized from 20 parts of cyclohexane to obtain 0.6 parts of (2-methylphenyl)phenyl selenide.

<Production Example 2>
<Synthesis of (3,5-dimethylphenyl)phenyl selenide>
The same procedure as in Production Example 1 was repeated except that 1.0 part of 2-methylphenyl bromide was replaced with 1.0 part of 3,5-dimethylphenyl bromide, to obtain 0.5 part of (3,5-dimethylphenyl)phenyl selenide.

<Production Example 3>
<Synthesis of (4-methylphenyl)phenyl selenide>
The same procedure as in Production Example 1 was repeated except that 1.0 part of 2-methylphenyl bromide was replaced with 1.0 part of 4-methylphenyl bromide, to obtain 0.6 part of (4-methylphenyl)phenyl selenide.

<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 replaced with 1.2 parts of 3-trifluoromethylphenyl bromide, to obtain 0.5 part of (4-methylphenyl)phenyl selenide.

<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, and 0.8 parts of sodium hypochlorite pentahydrate and 0.1 parts of tetrabutylammonium hydrogen sulfate were added and stirred at room temperature for 2 hours. The reaction solution was poured into water and the precipitate was separated by filtration to obtain a white solid. This white solid was washed with water and dried to obtain 0.8 parts of (3-trifluoromethylphenyl)phenyl selenoxide.

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).

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.

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.

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 changed to 1.4 parts of bis(4-fluorophenyl)iodonium triflate, the reaction time was changed to 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).

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.

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).

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 the mixture was washed three times. The dichloromethane layer was dried under reduced pressure to obtain 0.6 parts of (2-methylphenyl)diphenylselenonium nonaflate (P-2-1).

Example 8
<Synthesis of (3,5-methylphenyl)diphenylselenonium nonaflate (P-2-2)>
The same procedure as in Example 1 was repeated 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, to obtain 0.6 part of (3,5-methylphenyl)diphenylselenonium triflate.
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 the mixture was 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).

<Example 9>
<Synthesis of (4-tert-butylphenyl)(4-methylphenyl)phenylselenonium nonaflate (P-2-3)>
The same procedure as in Example 1 was repeated, 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 was replaced with 1.5 parts of bis(4-tert-butylphenyl)iodonium triflate, to obtain 0.5 parts of (4-tert-butylphenyl)(4-methylphenyl)phenylselenonium 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 the mixture was 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).

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 (manufactured by 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).

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 (manufactured by 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).

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

<Comparative Example 1>
<Synthesis of Ionic Photoacid Generator (P'-1)>
Triphenylsulfonium triflate (manufactured by Fuji Film Wako Chemical Co., Ltd.) was used as is.

<Comparative Example 2>
<Synthesis of Ionic Photoacid Generator (P'-2)>
According to Example 1 of Japanese Patent No. 4,934,306, (4-phenylthiophenyl)diphenylsulfonium triflate (P'-2) was obtained.

<Comparative Example 3>
<Synthesis of Ionic Photoacid Generator (P'-3)>
According to Example 6 of JP 2014-234348 A, (3-trifluoromethylphenyl)diphenylsulfonium triflate (P'-3) was obtained.

<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, and 2 parts of phenylselenol and 2.6 parts of a 50% aqueous potassium hydroxide solution were added thereto, followed by heating at 50° C. for 10 hours.
To the reaction mixture were added 50 parts of dichloromethane and 50 parts of water, 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).

<Comparative Example 5>
Five 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).

<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 photosensitive resin (copolymer of polyhydroxystyrene and t-butoxyacrylate) in a weight ratio of 20 times, and dissolved in propylene glycol monomethyl ether acetate (PGMEA) so that the molar concentration of the photoacid generator was 2.0 mM.

(Film formation)
The sample solution was spread on a substrate that had been 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 about 50 nm.

(exposure)
The film-formed sample was placed in BL-3 at the University of Hyogo's NewSUBARU Synchrotron Radiation Facility and irradiated with 13.5 nm synchrotron radiation.

(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.

(sensitivity)
The exposed sample was observed under a microscope to confirm 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: x
When the sensitivity of Comparative Example P'-1 is taken as 1, the sensitivity is less than 1, 0.75 or more: △
When the sensitivity of Comparative Example P'-1 is taken as 1, the sensitivity is less than 0.75, 0.5 or more: ◯ When the sensitivity of Comparative Example P'-1 is taken as 1, the sensitivity is less than 0.5: ⊚

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.

As shown in Table 1, the selenonium salt photoacid generator (P) of the present invention exhibits higher sensitivity to EUV than conventional sulfonium salts.

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, such as in the manufacture of semiconductors.

Claims (4)

A photoacid generator (P) comprising a selenonium salt represented by the following general formula (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 .] The photoacid generator (P ₎ according to claim 1, wherein in general formula (1), _X1 , X2 and X3 are F, _CF3 , _{C2F5 , C3F7} , _C4F9 or _{C6F5 .} The photoacid generator (P) according to claim 1 or 2 , which is intended for extreme ultraviolet (EUV) or electron beam (EB). A resin composition for photolithography (Q), comprising a photoacid generator (P) according to any one of claims 1 to 3 .