JP6591699B2 - 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 nonionic photoacid generator suitable for generating a strong acid by the action of ultraviolet rays (i rays), and a photolithographic resin composition containing the nonionic photoacid generator.

Conventionally, in the field of microfabrication represented by semiconductor manufacturing, a photolithography process using i-line having a wavelength of 365 nm as exposure light has been widely used.
As a resist material used in the photolithography process, for example, a resin composition containing a polymer having a tert-butyl ester group of carboxylic acid or a tert-butyl carbonate group of phenol and a photoacid generator is used. Yes. As photoacid generators, ionic photoacid generators such as triarylsulfonium salts (Patent Document 1), phenacylsulfonium salts having a naphthalene skeleton (Patent Document 2), and acid generators having an oxime sulfonate structure (Patent Documents) 3) Nonionic acid generators such as acid generators having a sulfonyldiazomethane structure (Patent Document 4) are known. Furthermore, by performing post-exposure heating (PEB), the tert-butyl ester group or tert-butyl carbonate group in the polymer is dissociated by this strong acid, and a carboxylic acid or a phenolic hydroxyl group is formed, and the ultraviolet irradiation part is formed. It becomes readily soluble in an alkaline developer. Pattern formation is performed using this phenomenon.

However, as the photolithography process becomes finer, the influence of the swelling that the pattern of the unexposed portion is swollen by the alkali developer increases, and it is necessary to suppress the swelling of the resist material.
In order to solve these problems, a method for suppressing swelling of the resist material by making the polymer in the resist material hydrophobic by adding an alicyclic skeleton or a fluorine-containing skeleton has been proposed.

  Ion photoacid generators lack compatibility with hydrophobic materials containing these alicyclic skeletons and fluorine-containing skeletons, so they exhibit sufficient resist performance due to phase separation in resist materials. There is a problem that the pattern cannot be formed. On the other hand, the nonionic photoacid generator has good compatibility with the hydrophobic material, but there is a problem that scum is generated in the exposed portion in the alkali development step. In addition, there is a problem that the sensitivity to i-line is insufficient and a problem that the allowance is narrow because it is decomposed by post-exposure heating (PEB) because heat resistance is insufficient.

Japanese Patent Laid-Open No. 50-151997 JP-A-9-118663 JP-A-6-67433 JP-A-10-213899

  Then, it aims at providing the non-ionic photo-acid generator which has high photosensitivity in i line | wire, is excellent in heat-resistant stability, is soluble in a hydrophobic material, and is excellent in alkali developability.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention provides a nonionic photoacid generator (A) represented by the following general formula (1); and a resin composition for photolithography comprising the nonionic photoacid generator (A) It is a thing (Q).

[In Formula (1), X is a monovalent organic group that can be eliminated by the action of an acid and substituted with a hydrogen atom, and Rf is a hydrocarbon group having 1 to 18 carbon atoms (a part or all of hydrogen is fluorine. Which may be substituted with ]

Since the nonionic photoacid generator (A) of the present invention is nonionic, it is more compatible with a hydrophobic material than the ionic acid generator. Moreover, since it has a naphthalimide skeleton, it has excellent heat stability and can be subjected to post-exposure heating (PEB).
Further, since it has a substituent on the naphthalimide skeleton, it can act on the electronic state of naphthalene ring and has a high molar extinction coefficient for i-line. Thereby, by irradiating with i-line, the nonionic photoacid generator (A) can be easily decomposed to generate sulfonic acid which is a strong acid.
Further, since X can be eliminated by the action of an acid and replaced with a hydrogen atom, only the exposed area has excellent affinity for an alkaline developer, and scum is less generated in the exposed area.

For this reason, the resin composition for photolithography (Q) containing the nonionic photoacid generator (A) of the present invention is highly sensitive to i-line and has an allowance in post-exposure heating (PEB). Excellent workability because it is wide.
Furthermore, the resin composition for photolithography (Q) of the present invention generates little scum in the alkali development step and can provide a good resist pattern.

  The nonionic acid generator (A) of the present invention is represented by the following general formula (1).

  In the formula (1), X is a monovalent organic group that can be eliminated by the action of an acid and substituted with a hydrogen atom, and Rf is a hydrocarbon group having 1 to 18 carbon atoms (a part or all of hydrogen is fluorine. Which may be substituted).

  The monovalent organic group that can be eliminated by the action of an acid of X and substituted with a hydrogen atom is represented by a 1-branched alkyl group, a silyl group, an acyl group, an alkyloxycarbonyl group, and the following general formula (2). Groups.

In Formula (2), R ¹ represents a hydrocarbon group having 1 to 10 carbon atoms, R ² and R ³ represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ¹ and R ² or R ³ are mutually They may combine to form a ring structure.

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

  Examples of the silyl group include trimethylsilyl group, ethyldimethylsilyl group, methyldiethylsilyl group, triethylsilyl group, isopropyldimethylsilyl group, methyldiisopropylsilyl group, triisopropylsilyl group, tert-butyldimethylsilyl group, methyldi-tert- Examples include tricarbylsilyl groups such as butylsilyl group, tri-tert-butylsilyl group, phenyldimethylsilyl group, methyldiphenylsilyl group, and triphenylsilyl group.

  Examples of the acyl group include acetyl group, propionyl group, butyryl group, heptanoyl group, hexanoyl group, valeryl group, pivaloyl group, isovaleryl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, oxalyl group, malonyl group, succinyl group. Group, glutaryl group, adipoyl group, piperoyl group, suberoyl group, azelaoil group, sebacoyl group, acryloyl group, propioroyl group, methacryloyl group, crotonoyl group, oleoyl group, maleoyl group, fumaroyl group, mesaconoyl group, camphoroyl group, benzoyl group , Phthaloyl group, isophthaloyl group, terephthaloyl group, naphthoyl group, toluoyl group, hydroatropoyl group, atropoyl group, cinnamoyl group, furoyl group, thenoyl group, nicotinoyl group, isonicoti Yl group, p- toluenesulfonyl group, and mesyl group, and the like.

  Examples of the group represented by the general formula (2) include methoxymethyl group, ethoxymethyl group, benzyloxymethyl group, 1-methoxyethyl group, 1-ethoxyethyl group, 1-ethoxypropyl group, 1-propoxyethyl. Group, 1-phenoxyethyl group, 1-benzyloxyethyl group, tetrahydropyranyl group, tetrahydrofuranyl group and the like.

  The alkyloxycarbonyl group is preferably an alkyloxycarbonyl group represented by the following general formula (3), for example, a methoxycarbonyl group, an ethoxycarbonyl group, an isopropoxycarbonyl group, a 2-ethylhexyloxycarbonyl group, or a tert-butoxycarbonyl group. Groups and the like.

In formula (3), R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, may have a ring structure or a branched structure, and are bonded to each other. A ring structure may be formed.

  Of these X, from the viewpoint of ease of elimination by the action of an acid and by-products upon elimination, preferably a silyl group, an alkyloxycarbonyl group and a group represented by the general formula (2) More preferably an alkyloxycarbonyl group, and particularly preferably a tert-butoxycarbonyl group and a 2-ethylhexyloxycarbonyl group.

Rf is a hydrocarbon group having 1 to 18 carbon atoms (part or all of hydrogen may be substituted with fluorine). The hydrocarbon group having 1 to 18 carbon atoms may have a substituent.
Examples of the hydrocarbon group having 1 to 18 carbon atoms include an alkyl group, an aryl group, and a heterocyclic hydrocarbon group.

  Examples of the alkyl group include linear alkyl groups having 1 to 18 carbon atoms (methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, etc.), C1-C18 branched alkyl groups (isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, isooctadecyl, etc.), and carbon Examples thereof include cycloalkyl groups having a number of 3 to 18 (such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 4-decylcyclohexyl and 10-camphoryl).

  Examples of the aryl group include aryl groups having 6 to 10 carbon atoms (such as phenyl, tolyl, dimethylphenyl, naphthyl, and pentafluorophenyl).

  Examples of the heterocyclic hydrocarbon group include a heterocyclic hydrocarbon group having 4 to 18 carbon atoms (thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, quinolyl. , Isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thiantenyl, phenoxazinyl, phenoxathinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, and dibenzofuranyl).

  Examples of the group in which part or all of hydrogen of the hydrocarbon group having 1 to 18 carbon atoms is substituted with fluorine include a linear alkyl group (Rf1) in which a hydrogen atom represented by CxFy is substituted with a fluorine atom, a branched chain Examples include an alkyl group (Rf2), a cycloalkyl group (Rf3), and an aryl group (Rf4).

  Examples of the linear alkyl group (Rf1) in which a hydrogen atom is substituted with a fluorine atom include a trifluoromethyl group (x = 1, y = 3), a pentafluoroethyl group (x = 2, y = 5), and hepta. Fluoropropyl group (x = 3, y = 7), nonafluorobutyl group (x = 4, y = 9), perfluorohexyl group (x = 6, y = 13), and perfluorooctyl group (x = 8 , Y = 17).

  Examples of the branched alkyl group (Rf2) in which a hydrogen atom is substituted with a fluorine atom include a perfluoroisopropyl group (x = 3, y = 7) and a perfluoro-tert-butyl group (x = 4, y = 9). And a perfluoro-2-ethylhexyl group (x = 8, y = 17).

  Examples of the cycloalkyl group (Rf3) in which a hydrogen atom is substituted with a fluorine atom include a perfluorocyclobutyl group (x = 4, y = 7), a perfluorocyclopentyl group (x = 5, y = 9), Examples thereof include a fluorocyclohexyl group (x = 6, y = 11) and a perfluoro (1-cyclohexyl) methyl group (x = 7, y = 13).

  Examples of the aryl group (Rf4) in which a hydrogen atom is substituted with a fluorine atom include a pentafluorophenyl group (x = 6, y = 5) and a 3-trifluoromethyltetrafluorophenyl group (x = 7, y = 7) and the like.

  Of Rf, a linear alkyl group (Rf1) in which a hydrogen atom is substituted with a fluorine atom is preferable from the viewpoints of decomposability of a sulfonic acid ester moiety, deprotection of a photoresist, and availability of raw materials. A branched alkyl group (Rf2) and an aryl group (Rf4), more preferably a linear alkyl group (Rf1) and an aryl group (Rf4), particularly preferably a trifluoromethyl group (x = 1, y = 3), pentafluoroethyl group (x = 2, y = 5), heptafluoropropyl group (x = 3, y = 7), nonafluorobutyl group (x = 4, y = 9), and pentafluoro It is a phenyl group (x = 6, y = 5).

  Of the nonionic photoacid generators represented by the general formula (1), preferred specific examples are shown below.

  The method for synthesizing the nonionic photoacid generator (A) of the present invention is not particularly limited as long as the target product can be synthesized. For example, 3-hydroxy-1,8-naphthalic anhydride and silyl chloride, 3,4- Hydroxylamine is reacted with a precursor (P1) obtained by reacting dihydro-2H-pyran or di-tert-butyl dicarbonate. It can then be synthesized by reacting the corresponding sulfonic anhydride or sulfonic acid chloride.

The reaction conditions between 3-hydroxy-1,8-naphthalic anhydride and silyl chloride, 3,4-dihydro-2H-pyran, di-tert-butyl dicarbonate or the like are 1 at a temperature of -30 to 80 ° C. It is preferably ˜50 hours, and it is preferable to use a reaction solvent, a base catalyst, and an acid catalyst in order to complete the reaction quickly and with good yield.
The reaction solvent is not particularly limited, but acetonitrile, tetrahydrofuran, dichloromethane, chloroform and the like are preferable. As the base catalyst, for example, pyridine, methylmorpholine, dimethylaminopyridine, 2,6-lutidine, triethylamine, imidazole, DBU, sodium hydride and the like are preferable, and as the acid catalyst, p-toluenesulfonic acid is usually used. 1 to 100 mol% is added to 3-hydroxy-1,8-naphthalic anhydride.
The molar ratio of 3-hydroxy-1,8-naphthalic anhydride and silyl chloride, 3,4-dihydro-2H-pyran or di-tert-butyl dicarbonate is usually 1: 1 to 1: 2. .

  The nonionic photoacid generator (A) of the present invention obtained by reacting the precursor (P1) with hydroxylamine and then reacting with the corresponding sulfonic acid anhydride or sulfonic acid chloride is suitable as required. It can be purified by recrystallization from an organic solvent.

The nonionic photoacid generator (A) 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.

  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 and 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 Fine diethylene glycol monobutyl ether acetate, etc.) and the like.

  When using a solvent, the usage-amount of a solvent has preferable 15-1000 weight part with respect to 100 weight part of photoacid generators of this invention, More preferably, it is 30-500 weight part.

Since the resin composition for photolithography (Q) of the present invention contains the nonionic photoacid generator (A) as an essential component, the exposed portion and the unexposed portion are exposed by performing ultraviolet irradiation and post-exposure heating (PEB). Difference in solubility in the developer of the part. A nonionic photoacid generator (A) can be used individually by 1 type or in combination of 2 or more types.
Examples of the resin composition (Q) for photolithography include a mixture of a negative chemical amplification resin (QN) and a nonionic photoacid generator (A); and a positive chemical amplification resin (QP) and a nonionic photoacid. A mixture with a generator (A) is mentioned.

  The negative chemical amplification resin (QN) is composed of a phenolic hydroxyl group-containing resin (QN1) and a crosslinking agent (QN2).

  The phenolic hydroxyl group-containing resin (QN1) is not particularly limited as long as it contains a phenolic hydroxyl group. For example, a novolak resin, a polyhydroxystyrene, a copolymer of hydroxystyrene, a copolymer of hydroxystyrene and styrene Copolymers, copolymers of hydroxystyrene, styrene and (meth) acrylic acid derivatives, phenol-xylylene glycol condensation resins, cresol-xylylene glycol condensation resins, polyimides containing phenolic hydroxyl groups, polyamics containing phenolic hydroxyl groups An acid, a phenol-dicyclopentadiene condensation resin, or the like is used. Among these, novolak resins, polyhydroxystyrene, copolymers of hydroxystyrene, copolymers of hydroxystyrene and styrene, copolymers of hydroxystyrene, styrene and (meth) acrylic acid derivatives, phenol-xylylene glycol condensation Resins are preferred. In addition, these phenolic hydroxyl group containing resin (QN1) may be used individually by 1 type, and 2 or more types may be mixed and used for it.

The novolak resin can be obtained, for example, by condensing phenols and aldehydes 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- Examples include trimethylphenol, catechol, resorcinol, pyrogallol, α-naphthol, β-naphthol and the like.
Examples of the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

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

The phenolic hydroxyl group-containing resin (QN1) may contain a phenolic low molecular weight compound as a part of the component.
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-hydroxy) Phenyl) ethane, 4,4 '- {1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene} bisphenol and the like. These phenolic low molecular weight compounds may be used alone or in combination of two or more.

  The content ratio of the phenolic low molecular weight compound in the phenolic hydroxyl group-containing resin (QN1) is preferably 40% by weight or less, more preferably, based on 100% by weight of the phenolic hydroxyl group-containing resin (QN1). 1 to 30% by weight.

The weight average molecular weight of the phenolic hydroxyl group-containing resin (QN1) is preferably 2000 or more, more preferably 2000 from the viewpoint of the resolution, thermal shock resistance, heat resistance, residual film ratio, etc. of the obtained insulating film. About 20,000.
Further, the content of the phenolic hydroxyl group-containing resin (QN1) in the negative chemically amplified resin (QN) is 30 to 90% by weight when the entire composition excluding the solvent is 100% by weight. Is more preferable, and 40 to 80% by weight is more preferable. When the content of the phenolic hydroxyl group-containing resin (QN1) is 30 to 90% by weight, the film formed using the photosensitive insulating resin composition has sufficient developability with an alkaline aqueous solution. Therefore, it is preferable.

  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 a strong acid generated from the nonionic photoacid generator (A).

  Examples of the crosslinking agent (QN2) include bisphenol A epoxy compounds, bisphenol F epoxy compounds, bisphenol S epoxy compounds, novolac resin epoxy compounds, resole resin epoxy compounds, poly (hydroxystyrene) epoxy compounds, and oxetanes. Compound, methylol group-containing melamine compound, methylol group-containing benzoguanamine compound, methylol group-containing urea compound, methylol group-containing phenol compound, alkoxyalkyl group-containing melamine compound, alkoxyalkyl group-containing benzoguanamine compound, alkoxyalkyl group-containing urea compound, alkoxyalkyl group -Containing phenol compound, carboxymethyl group-containing melamine resin, carboxymethyl group-containing benzoguanamine resin, carboxymethyl group-containing urea Fat, carboxymethyl group-containing phenol resin, carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, mention may be made of carboxymethyl group-containing urea compounds and carboxymethyl group-containing phenol compounds and the like.

  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 More preferred are methoxymethyl group-containing melamine compounds (for example, hexamethoxymethyl melamine), methoxymethyl group-containing glycoluril compounds, methoxymethyl group-containing urea compounds, and the like. The methoxymethyl group-containing melamine compound is a trade name such as CYMEL300, CYMEL301, CYMEL303, CYMEL305 (manufactured by Mitsui Cyanamid Co., Ltd.), and the methoxymethyl group-containing glycoluril compound is a trade name such as CYMEL1174 (manufactured by Mitsui Cyanamid Co., Ltd.). Further, the methoxymethyl group-containing urea compound is commercially available under a trade name such as MX290 (manufactured by Sanwa Chemical Co., Ltd.).

  The content of the crosslinking agent (QN2) is usually from 5 to 5 with respect to all acidic functional groups in the phenolic hydroxyl group-containing resin (QN1) from the viewpoints of reduction of the remaining film ratio, meandering and swelling of the pattern, and developability. 60 mol%, preferably 10 to 50 mol%, more preferably 15 to 40 mol%.

As a positive chemical amplification resin (QP), a part of hydrogen atoms of acidic functional groups in an alkali-soluble resin (QP1) containing one or more acidic functional groups such as phenolic hydroxyl group, carboxyl group, or sulfonyl group Or the protecting group introduction | transduction resin (QP2) which substituted all by the acid dissociable group is mentioned.
The acid dissociable group is a group that can be dissociated in the presence of a strong acid generated from the nonionic photoacid generator (A).
The protecting group-introduced resin (QP2) is itself insoluble in alkali or hardly 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 one as the hydroxyl group-containing resin (QN1) can be used.

  The carboxyl group-containing resin (QP12) is not particularly limited as long as it is a polymer having a carboxyl group. For example, the carboxyl group-containing vinyl monomer (Ba) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb) are vinyl-polymerized. Can be obtained.

Examples of the carboxyl group-containing vinyl monomer (Ba) include unsaturated monocarboxylic acids [(meth) acrylic acid, crotonic acid, cinnamic acid and the like], unsaturated polyvalent (2-4 valent) carboxylic acids [(anhydrous) maleic acid, and the like. Acid, itaconic acid, fumaric acid, citraconic acid, etc.], unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) ester [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, citraconic acid monoalkyl ester, etc. And salts thereof [alkali metal salts (sodium salt, potassium salt, etc.), alkaline earth metal salts (calcium salt, magnesium salt, etc.), amine salts, ammonium salts, etc.].
Of these, unsaturated monocarboxylic acids are preferred from the viewpoint of polymerizability and availability, and (meth) acrylic acid is more preferred.

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

  Examples of the (meth) acrylic acid ester (Bb1) include alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group [for example, 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 and the like] and alicyclic group-containing (meth) acrylate [dicyclopentanyl (meth) acrylate, Sidiclopentenyl (meth) acrylate, isobornyl (meth) acrylate, etc.].

  Examples of the aromatic hydrocarbon monomer (Bb2) include hydrocarbon monomers having a styrene skeleton [for example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene. Cyclohexyl styrene and benzyl styrene] and vinyl naphthalene.

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

The sulfonic acid group-containing resin (QP13) is not particularly limited as long as it is a polymer having a sulfonic acid group. For example, a sulfonic acid group-containing vinyl monomer (Bc) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb) are used. Obtained by vinyl polymerization.
As the hydrophobic group-containing vinyl monomer (Bb), the same ones as described above can be used.

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

  The charged monomer molar ratio of (Bc) / (Bb) in the sulfonic acid group-containing resin (QP13) is usually from 10 to 100/0 to 90, preferably from 10 to 80/20 to 90, more preferably from the viewpoint of developability. Is 25-85 / 15-75.

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

In addition, the HLB value in this invention is an HLB value by the Oda method, is a hydrophilicity-hydrophobicity balance value, and can be calculated from the ratio of the organic value and the inorganic value of an organic compound. .
HLB≈10 × inorganic / organic In addition, the inorganic value and the organic value are described on page 501 of the document “Synthesis of Surfactant and its Application” (published by Tsuji Shoten, written by Oda, Teramura); It is described in detail on page 198 of “Introduction to New Surfactants” (Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.).

  Examples of the acid dissociable group in the protective group-introducing 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. Examples include a dissociable group. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of 1-substituted methyl group include methoxymethyl group, methylthiomethyl group, ethoxymethyl group, ethylthiomethyl group, methoxyethoxymethyl group, benzyloxymethyl group, benzylthiomethyl group, phenacyl group, bromophenacyl group, methoxyphena Sil group, methylthiophenacyl group, α-methylphenacyl group, cyclopropylmethyl group, benzyl group, diphenylmethyl group, triphenylmethyl group, bromobenzyl group, nitrobenzyl group, methoxybenzyl group, methylthiobenzyl group, ethoxybenzyl Group, ethylthiobenzyl group, piperonyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, n-propoxycarbonylmethyl group, i-propoxycarbonylmethyl group, n-butoxycarbonylmethyl group, tert-butyl group Alkoxycarbonylmethyl group, and the like.

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

  Examples of the 1-branched alkyl group include i-propyl group, sec-butyl group, tert-butyl group, 1,1-dimethylpropyl group, 1-methylbutyl group, 1,1-dimethylbutyl group and the like. it can.

  Examples of the silyl group include trimethylsilyl group, ethyldimethylsilyl group, methyldiethylsilyl group, triethylsilyl group, i-propyldimethylsilyl group, methyldi-i-propylsilyl group, tri-i-propylsilyl group, tert-butyl. Examples thereof include tricarbylsilyl groups such as a dimethylsilyl group, a methyldi-tert-butylsilyl group, a tri-tert-butylsilyl group, a phenyldimethylsilyl group, a methyldiphenylsilyl group, and a triphenylsilyl group.

  Examples of the germyl group include trimethylgermyl group, ethyldimethylgermyl group, methyldiethylgermyl group, triethylgermyl group, isopropyldimethylgermyl group, methyldi-i-propylgermyl group, and tri-i-propylgel. Tricarbylgermyl groups such as mil group, tert-butyldimethylgermyl group, methyldi-tert-butylgermyl group, tri-tert-butylgermyl group, phenyldimethylgermyl group, methyldiphenylgermyl group, triphenylgermyl group, etc. Can be mentioned.

  Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, i-propoxycarbonyl group, tert-butoxycarbonyl group and the like.

  Examples of the acyl group include acetyl group, propionyl group, butyryl group, heptanoyl group, hexanoyl group, valeryl group, pivaloyl group, isovaleryl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, oxalyl group, malonyl group, succinyl group. Group, glutaryl group, adipoyl group, piperoyl group, suberoyl group, azelaoil group, sebacoyl group, acryloyl group, propioroyl group, methacryloyl group, crotonoyl group, oleoyl group, maleoyl group, fumaroyl group, mesaconoyl group, camphoroyl group, benzoyl group , Phthaloyl group, isophthaloyl group, terephthaloyl group, naphthoyl group, toluoyl group, hydroatropoyl group, atropoyl group, cinnamoyl group, furoyl group, thenoyl group, nicotinoyl group, isonicoti Yl group, p- toluenesulfonyl group, and mesyl group.

  Examples of the cyclic acid dissociable group 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, and a tetrahydrothiofuranyl group. Group, 3-bromotetrahydropyranyl group, 4-methoxytetrahydropyranyl group, 4-methoxytetrahydrothiopyranyl group, 3-tetrahydrothiophene-1,1-dioxide group and the like.

  Among these acid dissociable groups, tert-butyl group, benzyl group, 1-methoxyethyl group, 1-ethoxyethyl group, trimethylsilyl group, tert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, tetrahydropyranyl group, A tetrahydrofuranyl group, a tetrahydrothiopyranyl group, a tetrahydrofuranyl group, and the like are preferable.

  Introduction rate of acid-dissociable groups in protecting group-introducing resin (QP2) {Ratio of the number of acid-dissociable groups to the total number of unprotected acidic functional groups and acid-dissociable groups in protecting group-introducing resin (QP2) } Cannot be defined unconditionally depending on the type of the acid-dissociable group or the alkali-soluble resin into which the group is introduced, but is preferably 10 to 100%, 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, more preferably 3, 000-100,000.

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

The content of the nonionic photoacid generator (A) based on the weight of the solid content of the resin composition for photography (Q) is preferably 0.001 to 20% by weight, more preferably 0.01 to 15% by weight. %, Particularly preferably 0.05 to 7% by weight.
If it is 0.001% by weight or more, the sensitivity to ultraviolet rays can be exhibited more satisfactorily, and if it is 20% by weight or less, the physical properties of the insoluble part in the alkali developer can be further improved.

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

The organic solvent for dissolving the resin composition for photography (Q) is not particularly limited as long as the resin composition can be dissolved and the resin solution can be adjusted to physical properties (viscosity, etc.) applicable to spin coating or the like. Not. For example, known solvents such as N-methylpyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, 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, 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) from the viewpoint of drying temperature and the like Are preferable, and can be used alone or in combination of two or more.
When the 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 based on the weight of the solid content of the resin composition for photography (Q). It is 40 to 900% by weight, particularly preferably 50 to 800% by weight.

  The drying condition of the resin solution after coating varies depending on the solvent used, but is preferably carried out at 50 to 2000 ° C. for 2 to 30 minutes, and the residual solvent amount of the resin composition for photography (Q) after drying ( Weight%) and the like.

  After the resist is formed on the substrate, the wiring pattern shape is irradiated with light. Then, after performing post-exposure heating (PEB), alkali development is performed to form a wiring pattern.

As a method of irradiating with light, there is a method of exposing a resist with actinic rays through a photomask having a wiring pattern. The actinic ray used for the light irradiation is not particularly limited as long as the nonionic photoacid generator (A) in the resin composition for photography (Q) of the present invention can be decomposed.
Actinic rays include low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, xenon lamp, metal halogen lamp, electron beam irradiation device, X-ray irradiation device, laser (argon laser, dye laser, nitrogen laser, LED, helium Cadmium laser). Of these, high pressure mercury lamps and ultrahigh pressure mercury lamps are preferred.

The temperature of post-exposure heating (PEB) is usually 40 to 200 ° C, preferably 50 to 190 ° C, more preferably 60 to 180 ° C. If the temperature is lower than 40 ° C., the deprotection reaction or the crosslinking reaction cannot be sufficiently performed. Therefore, there is not enough difference in solubility between the ultraviolet irradiated portion and the ultraviolet unirradiated portion, and a pattern cannot be formed. There is.
As the heating time, it is usually difficult to control the time and temperature if it is less than 0.5 to 120 minutes, and if it is longer than 120 minutes, there is a problem that productivity is lowered.

Examples of the alkali developing method include a method of dissolving and removing the wiring pattern shape using an alkali developer. The alkali developer is not particularly limited as long as the solubility of the ultraviolet light irradiated portion and the ultraviolet light unirradiated portion of the resin composition for photography (Q) can be varied.
Examples of the alkali developer include a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, sodium hydrogen carbonate, and a tetramethylammonium salt aqueous solution.
These alkaline developers may contain a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropyl alcohol, tetrahydrofuran, and N-methylpyrrolidone.

As a developing method, there are a dip method, a shower method, and a spray method using an alkali developer, and a spray method is preferable.
The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the resist thickness.

Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”. (Examples 6 to 7 are reference examples.)

<Production Example 1>
<Method for producing N-hydroxy-3-tert-butoxycarbonyloxy-1,8-naphthalimide [Intermediate (1)]>
Disperse 5.5 parts of 3-hydroxy-1,8-naphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5.9 parts di-tert-butyl dicarbonate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 32 parts of acetonitrile. Then, 2.2 parts of pyridine was added and stirred at 50 ° C. for 2 hours. After cooling to room temperature, it was poured into water and the precipitate was filtered off to obtain a white solid. This white solid was washed with water and dried to obtain 8.1 parts of 3-tert-butoxycarbonyloxy-1,8-naphthalic anhydride.
8.1 parts of the resulting 3-tert-butoxycarbonyloxy-1,8-naphthalic anhydride was dissolved in 137 parts of acetonitrile, and 2.0 parts of a hydroxylamine aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., 50% aqueous solution). And 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 give 8.0 parts of the title compound [Intermediate (1)].

<Production Example 2>
<Method for Producing N-Hydroxy-3- (2-isopropyl-5-methyl-cyclohexoxy) carbonyloxy-1,8-naphthalimide [Intermediate (2)]>
Triethylamine 2 was prepared by dispersing 5.5 parts of 3-hydroxy-1,8-naphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5.9 parts of menthyl chloroformate (manufactured by Tokyo Chemical Industry Co., Ltd.) in 47 parts of acetonitrile. .8 parts was added and stirred at 50 ° C. for 2 hours. After cooling to room temperature, it was poured into water and the precipitate was filtered off to obtain a white solid. This white solid was washed with water and dried to obtain 8.0 parts of 3- (2-isopropyl-5-methyl-cyclohexoxy) carbonyloxy-1,8-naphthalic anhydride.
The obtained 3- (2-isopropyl-5-methyl-cyclohexoxy) carbonyloxy-1,8-naphthalic anhydride 8.0 parts was dissolved in 124 parts of acetonitrile, and a hydroxylamine aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd.). , 50% aqueous solution) was added and 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 give 4.0 parts of the title compound [Intermediate (2)].

<Production Example 3>
<Synthesis Method of N-Hydroxy-3- (2-tetrahydropyranyl) oxy-1,8-naphthalimide [Intermediate (3)]>
5.5 parts of 3-hydroxy-1,8-naphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.), 2.3 parts of 3,4-dihydro-2H-pyran (manufactured by Tokyo Chemical Industry Co., Ltd.) and 32 parts of acetonitrile 4.9 parts of p-toluenesulfonic acid was added and stirred at 50 ° C. for 2 hours. After cooling to room temperature, it was poured into water and the precipitate was filtered off to obtain a reddish brown solid. This reddish brown solid was washed with water and dried to obtain 7.6 parts of 3- (2-tetrahydropyranyl) oxy-1,8-naphthalic anhydride.
7.6 parts of the obtained 3- (2-tetrahydropyranyl) oxy-1,8-naphthalic anhydride was dissolved in 137 parts of acetonitrile, and a hydroxylamine aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., 50% aqueous solution) 2 0.0 part was added and it stirred at room temperature for 2 hours. The reaction solution was poured into water and the precipitate was filtered off to obtain a reddish brown solid. The reddish brown solid was washed with water and dried to obtain 7.6 parts of the title compound [intermediate (3)].

<Production Example 4>
<Synthesis Method of N-Hydroxy-3-trimethylsilyloxy-1,8-naphthalimide [Intermediate (4)]>
Disperse 5.5 parts of 3-hydroxy-1,8-naphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2.9 parts of trimethylsilyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 32 parts of acetonitrile, and add 2. 8 parts were added and stirred at 50 ° C. for 2 hours. After cooling to room temperature, it was poured into water and the precipitate was filtered off to obtain a reddish brown solid. This reddish brown solid was washed with water and dried to obtain 7.3 parts of 3-trimethylsilyloxy-1,8-naphthalic anhydride.
7.3 parts of the obtained 3-trimethylsilyloxy-1,8-naphthalic anhydride was dissolved in 137 parts of acetonitrile, and 2.0 parts of a hydroxylamine aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., 50% aqueous solution) was added. Stir at room temperature for 2 hours. The reaction solution was poured into water and the precipitate was filtered off to obtain a reddish brown solid. The reddish brown solid was washed with water and dried to obtain 7.3 parts of the title compound [intermediate (4)].

<Example 1>
<Synthesis of 3-tert-butoxycarbonyloxy-1,8-naphthalic acid imide trifluoromethanesulfonate [nonionic photoacid generator (A-1)]>
8.0 parts of N-hydroxy-3-tert-butoxycarbonyloxy-1,8-naphthalimide [Intermediate (1)] obtained in Production Example 1 is dispersed in 52 parts of dichloromethane to obtain 3.8 parts of pyridine. Then, 10.2 parts of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while cooling to 0 ° C. or lower, and the mixture was stirred for 2 hours. The reaction solution was poured into water while maintaining 0 ° C. and washed four times, and then dichloromethane was distilled off under reduced pressure to obtain 10.0 parts of the title compound [nonionic photoacid generator (A-1)]. Obtained.

<Example 2>
<Synthesis Method of 3-tert-Butoxycarbonyloxy-1,8-Naphthalimidopentafluoroethanesulfonate [Nonionic Photoacid Generator (A-2)]>
In Example 1, 10.2 parts of trifluoromethanesulfonic anhydride was changed to 7.9 parts of pentafluoroethanesulfonic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), and the same operation as in Example 1 was performed. 11.1 parts of the title compound [nonionic photoacid generator (A-2)] were obtained.

<Example 3>
<Synthesis Method of 3-tert-Butoxycarbonyloxy-1,8-Naphthalimidoheptafluoropropanesulfonate [Nonionic Photoacid Generator (A-3)]>
In Example 1, 10.2 parts of trifluoromethanesulfonic anhydride was changed to 9.7 parts of heptafluoropropanesulfonic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), and the same operation as in Example 1 was performed. 12.2 parts of the title compound [nonionic photoacid generator (A-3)] were obtained.

<Example 4>
<Synthesis Method of 3-tert-Butoxycarbonyloxy-1,8-naphthalic acid imidononafluorobutanesulfonate [nonionic photoacid generator (A-4)]>
In Example 1, 10.2 parts of trifluoromethanesulfonic anhydride was changed to 11.6 parts of nonafluorobutanesulfonic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.). 13.3 parts of the title compound [nonionic photoacid generator (A-4)] were obtained.

<Example 5>
<Synthesis Method of 3-tert-Butoxycarbonyloxy-1,8-Naphthalimidopentafluorobenzenesulfonate [Nonionic Photoacid Generator (A-5)]>
In Example 1, except that 10.2 parts of trifluoromethanesulfonic anhydride was changed to 9.7 parts of pentafluorobenzenesulfonic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), the same operation as in Example 1 was performed, 12.2 parts of the title compound [nonionic photoacid generator (A-5)] were obtained.

<Example 6>
<Synthesis Method of 3- (2-Isopropyl-5-methyl-cyclohexoxy) carbonyloxy-1,8-naphthalimide trifluoromethanesulfonate [nonionic photoacid generator (A-6)]>
4.0 parts of N-hydroxy-3- (2-isopropyl-5-methyl-cyclohexoxy) carbonyloxy-1,8-naphthalimide [Intermediate (2)] obtained in Production Example 2 was added to 21 parts of dichloromethane. After adding 1.5 parts of pyridine to the mixture, 4.1 parts of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while cooling to 0 ° C. or lower and stirred for 2 hours. The reaction solution was poured into water while maintaining 0 ° C. and washed four times, and then dichloromethane was distilled off under reduced pressure to obtain 4.1 parts of the title compound [nonionic photoacid generator (A-6)]. Obtained.

<Example 7>
<Synthesis Method of 3- (2-Tetrahydropyranyl) oxy-1,8-naphthalimide trifluoromethanesulfonate [nonionic photoacid generator (A-7)]>
7.6 parts of N-hydroxy-3- (2-tetrahydropyranyl) oxy-1,8-naphthalimide [intermediate (3)] obtained in Production Example 3 is dispersed in 52 parts of dichloromethane to give pyridine 3 After adding 8 parts, 10.2 parts of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while cooling to 0 ° C. or lower and stirred for 2 hours. The reaction solution was poured into water while maintaining 0 ° C. and washed with water four times, and then dichloromethane was distilled off under reduced pressure to obtain 9.7 parts of the title compound [nonionic photoacid generator (A-7)]. Obtained.

<Example 8>
<Synthesis Method of 3-Trimethylsilyloxy-1,8-Naphthalimide Imidotrifluoromethanesulfonate [Nonionic Photoacid Generator (A-8)]>
7.3 parts of N-hydroxy-3-trimethylsilyloxy-1,8-naphthalimide [Intermediate (4)] obtained in Production Example 4 was dispersed in 52 parts of dichloromethane, and 3.8 parts of pyridine were added. Thereafter, 10.2 parts of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise while cooling to 0 ° C. or lower, and the mixture was stirred for 2 hours. The reaction solution was poured into water while maintaining 0 ° C. and washed four times, and then dichloromethane was distilled off under reduced pressure to obtain 9.7 parts of the title compound [nonionic photoacid generator (A-8)]. Obtained.

<Comparative Example 1>
<Synthesis Method of 1,8-Naphthalimide Imidotrifluoromethanesulfonate [Nonionic Photoacid Generator (A′-1)]>
1,8-naphthalimide trifluoromethanesulfonate (manufactured by Aldrich) represented by the following formula (4) was used as it was.

<Comparative Example 2>
<Synthesis Method of 3-Hydroxy-1,8-Naphthalimide Imidotrifluoromethanesulfonate [Nonionic Photoacid Generator (A′-2)]>
10.0 parts of 3-tert-butoxycarbonyloxy-1,8-naphthalimide trifluoromethanesulfonate [nonionic photoacid generator (A-1)] obtained in Example 1 was dissolved in 52 parts of dichloromethane. Then, 4.0 parts of trifluoromethanesulfonic acid was added dropwise and stirred at room temperature for 1 hour. The precipitate was filtered off from the reaction solution, washed with water and dried to obtain 7.9 parts of a nonionic photoacid generator (A′-2) represented by the following formula (5).

<Comparative Example 3>
<(4-Phenylthiophenyl) diphenylsulfonium trifluoromethanesulfonate [Synthesis Method of Ionic Photoacid Generator (A′-3)]>
According to Example 1 of JP2007-091628A, (4-phenylthiophenyl) diphenylsulfonium trifluoromethanesulfonate represented by the following formula (6) [ion-based photoacid generator (A′-3) was obtained. .

<Examples 1-8, Comparative Examples 1-3>
As the performance evaluation of the photoacid generator, the nonionic photoacid generators (A-1) to (A-8) obtained in Examples 1 to 8 and the nonionic photoacid generator (A About the molar extinction coefficient, resist curability, thermal decomposition temperature, solvent solubility, and alkali developability of '-1), (A'-2) and comparative ionic photoacid generator (A'-3) Evaluation was performed by the following method, and the results are shown in Table 1.

<Molar extinction coefficient>
The synthesized photoacid generator was diluted to 0.25 mmol / L with acetonitrile, and the absorbance of a cell length of 1 cm was measured in the range of 200 nm to 500 nm using an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-2550). It was measured. The molar extinction coefficient (ε ₃₆₅ ) of i-line (365 nm) was calculated from the following formula.
ε ₃₆₅ (L · mol ⁻¹ · cm ⁻¹ ) = A ₃₆₅ /(0.00025 mol / L × ¹ cm)
[In the formula, A ₃₆₅ represents absorbance at ₃₆₅ nm. ]

<Resistance curability>
75 parts of phenolic resin (manufactured by DIC, “Phenolite TD431”), 25 parts of melamine curing agent (manufactured by Mitsui Cyanamid Co., Ltd., “Cymel 300”), 1 part of synthesized photoacid generator, and propylene glycol monomethyl ether 200 parts of a resin solution of acetate (hereinafter abbreviated as PGMEA) was applied on a 10 cm square glass substrate using a spin coater at 1000 rpm for 10 seconds. Next, after vacuum drying at 25 ° C. for 5 minutes, it was dried on a hot plate at 80 ° C. for 3 minutes to form a resist having a film thickness of about 3 μm. Using this resist with an ultraviolet irradiation device (OMW Mfg. Co., Ltd., HMW-661F-01), the wavelength was limited by an L-34 (Kenko Optical Co., Ltd. filter that cuts light of less than 340 nm) filter. A predetermined amount of light was exposed on the entire surface. The integrated exposure was measured at a wavelength of 365 nm. Subsequently, after performing post-exposure heating (PEB) for 10 minutes with a 120 ° C. normal air dryer, development was performed by immersing in a 0.5% potassium hydroxide solution for 30 seconds, followed by immediately washing with water and drying. The film thickness of this resist was measured using a shape measurement microscope (ultra-depth shape measurement microscope UK-8550, manufactured by Keyence Corporation). Here, the resist curability was evaluated according to the following criteria from the minimum exposure amount at which the change in resist film thickness before and after development was within 10%.
○: minimum exposure amount 250 mJ / cm ² or less △: Minimum exposure amount greater than ^{250mJ / cm 2, 500mJ / cm} 2 or less ×: Minimum exposure amount is greater than 500 mJ / cm ²

<Thermal decomposition temperature>
Using the differential thermal / thermogravimetric simultaneous measurement device (TG / DTA6200, manufactured by SII), the synthesized photoacid generator was subjected to weight change from 30 ° C. to 500 ° C. under a temperature rising condition of 10 ° C./min. The point at which 5% weight was measured was determined as the thermal decomposition temperature.

<Solvent solubility>
The synthesized photoacid generator was placed in a 0.1 g test tube, and propylene glycol monomethyl ether acetate (PGMEA) was added under temperature control at 25 ° C. until the photoacid generator was completely dissolved. When 20 g was not completely dissolved, it was evaluated as not dissolved.

<Alkali developability>
Take 0.5 parts of the synthesized photoacid generator in a test tube, add 2.38% tetramethylammonium hydroxide aqueous solution to 100 parts, and then in an aqueous solution of tetramethylammonium hydroxide for 1 minute with an ultrasonic cleaner. Dispersed. Prepare two dispersions of each photoacid generator for this dispersion, and use only one of them with an ultraviolet irradiation device (ECS-151U, manufactured by Eye Graphics Co., Ltd.) to limit the wavelength with a filter that cuts light of less than 340 nm. The irradiated ultraviolet light was irradiated at 100 mJ / cm ² . From the state of the dispersion after standing for 24 hours under light shielding, alkali developability was evaluated according to the following criteria.
○: completely dissolved △: not completely dissolved and turbid ×: not completely dissolved, and undissolved residue is deposited at the bottom of the test tube

As is clear from Table 1, the nonionic photoacid generators (A) of Examples 1 to 8 of the present invention have a molar extinction coefficient in the range of 500 to 10,000 and are excellent in resist curability. Further, it can be seen that the acid dissociable group is eliminated when irradiated with ultraviolet light, so that the polarity is increased and the alkali developability is excellent, so that the occurrence of scum is small. Moreover, it turns out that it has sufficient performance for using as a photoresist from the viewpoint of the solubility with respect to a solvent, and thermal decomposition temperature.
On the other hand, in Comparative Example 1 composed of a naphthylimide skeleton having no substituent, the naphthyl skeletons are easily molecularly aligned with each other, and the crystallinity is high, so that the solubility in a solvent is too low. Further, it can be seen that in Comparative Example 2 in which the hydroxyl group is not protected by the acid dissociable group, the resist curability and the solvent solubility are insufficient.
In Comparative Example 3 of the ionic photoacid generator, it can be seen that the resist curability is lowered because the dispersibility of the acid generator in the resist is low.

The nonionic photoacid generator (A) of the present invention has high photosensitivity to i-line and excellent alkali developability, so it is useful as a photolithography material for microfabrication represented by semiconductor manufacturing. It is.

Claims (4)

A nonionic photoacid generator (A) represented by the following general formula (1):

[In Formula (1), X is a silyl group or an alkyloxycarbonyl group , Rf represents a C1-C18 hydrocarbon group (a part or all of hydrogen may be substituted by fluorine). ] The nonionic photoacid generator (A) according to claim 1, wherein, in the general formula (1), X is an alkyloxycarbonyl group represented by the following general formula (3).

[In Formula (3), R ⁴ , R ⁵ and R ⁶ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and may have a ring structure or a branched structure, and may be bonded to each other. To form a ring structure. ] In the general formula (1), Rf is _{CF 3, C 2 F 5,} C 3 F 7, C 4 F 9 or _C 6 _{F 5} a is claim 1 or 2 non-ionic photoacid generators described in, ( A). The resin composition (Q) for photolithography containing the nonionic photoacid generator (A) in any one of Claims 1-3 .