Protective film-forming composition having an acetal structure

Abstract

To provide a composition that forms a protective film with excellent resistance against a semiconductor wet etching solution during the lithographic process when producing semiconductors; a method for producing a substrate with a resist pattern, to which the protective film is applied; and a method for producing semiconductor devices.SOLUTION: A composition for forming a protective film against a semiconductor wet etching solution is provided, which contains: a compound containing at least one acetal structure in its molecule, or a polymer thereof; and a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a protective film having excellent resistance to a semiconductor wet etching solution, preferably a basic hydrogen peroxide aqueous solution, in a lithography process in semiconductor manufacturing, and also to a method for manufacturing a substrate having a resist pattern to which the protective film is applied, and a method for manufacturing a semiconductor device. [Background technology]

[0002] 2. Description of the Related Art In semiconductor manufacturing, a lithography process is widely known in which a resist underlayer film is provided between a substrate and a resist film formed thereon, and a resist pattern having a desired shape is formed. Patent Document 1 discloses an antireflective coating composition for use with an overcoated photoresist, which contains a polymer having a glycidyl group and a polymer having an aromatic group substituted with a hydroxy group or the like, and a method for forming a photoresist underlayer film using the composition, followed by exposure, development, and pattern formation. Patent Document 2 discloses a method for forming a photoresist relief image by applying a composition containing a resin containing an epoxy-reactive group such as a hydroxy group and a crosslinked resin containing an epoxy group onto a substrate, and then forming a photoresist layer thereon. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-107185 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-187764 Summary of the Invention [Problem to be solved by the invention]

[0004] When the resist underlayer film is used as an etching mask to process the underlying substrate by wet etching, the resist underlayer film is required to have a good masking function against the wet etching solution during the processing of the underlying substrate. Conventionally, a method of adding gallic acid as an additive has been used to develop resistance to SC-1 (ammonia-hydrogen peroxide solution), a type of wet etching chemical. Furthermore, although it has been known that a catechol structure exhibits an effect of improving resistance to wet etching solutions for semiconductors (Patent Documents 1 and 2), the resistance to wet etching solutions for semiconductors has not yet been fully satisfactory. The object of the present invention is to solve these problems. [Means for solving the problem]

[0005] The present invention encompasses the following. [1] A protective film-forming composition for a semiconductor wet etching solution, comprising a compound containing at least one acetal structure in the molecule, or a polymer thereof, and a solvent. [2] The protective film-forming composition according to [1], wherein the acetal structure is a structure that protects adjacent hydroxy groups of an aromatic group. [3] The compound has formula (1): [ka] (In formula (1), R 1 and R 2 are each a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 40 carbon atoms, n1 is 0, 1, or 2; n2 is 1 or 2, A 1 represents a hydrogen atom or a hydroxy group, A 2 is -CH(R 0 )-A 4 indicates a group, R 0represents a hydrogen atom, a phenyl group optionally substituted with one to three hydroxy groups, or a benzodioxole group, A 3 , and A 4 represent the same or different monovalent organic groups. The protective film-forming composition according to [1], which contains a partial structure represented by the following formula: [4] The protective film-forming composition according to [3], wherein in the formula (1), n1 is 0 and n2 is 1. [5] In the formula (1), R 1 and R 2 are the same or different and are a hydrogen atom or a methyl group. [6] In the formula (1), R 1 and R 2 The protective film-forming composition according to [3], wherein [7] The protective film-forming composition according to any one of [1] to [6], further comprising a crosslinking catalyst. [8] The protective film-forming composition according to any one of [1] to [7], further comprising a crosslinking agent. [9] The protective film-forming composition according to any one of [1] to [8], further comprising a surfactant.

[10] A protective film, which is a fired product of a coating film made of the protective film-forming composition according to any one of [1] to [9].

[11] A method for producing a substrate having a resist pattern, comprising the steps of applying the protective film composition according to any one of [1] to [9] onto a semiconductor substrate and baking it to form a protective film as a resist underlayer film, the method being used in the production of semiconductors.

[12] A method for manufacturing a semiconductor device, comprising the steps of forming a protective film on a semiconductor substrate, on the surface of which an inorganic film may be formed, using a protective film-forming composition for a semiconductor wet etching solution according to any one of [1] to [9], forming a resist pattern on the protective film, dry-etching the protective film using the resist pattern as a mask to expose the surface of the inorganic film or the semiconductor substrate, and wet-etching and cleaning the inorganic film or the semiconductor substrate using the protective film after dry etching as a mask. [Effects of the Invention]

[0006] In the present invention, by introducing into the polymer a structure in which adjacent hydroxy groups are protected by acetal, high resistance to a wet etching solution for semiconductors can be achieved. DETAILED DESCRIPTION OF THE INVENTION

[0007] [Protective film forming composition] The protective film-forming composition for a semiconductor wet etching solution according to the present invention contains a compound having at least one acetal structure in the molecule or a polymer thereof, and a solvent.

[0008] [Compounds containing at least one acetal structure in the molecule] The acetal structure is preferably a structure that protects adjacent hydroxy groups of an aromatic group, and in this case, the compound contains, in the molecule, at least one aromatic group in which adjacent hydroxy groups are protected by an acetal. Such an acetal structure preferably has the formula (1): [ka] (In formula (1), R 1 and R 2 are each a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 40 carbon atoms, n1 is 0, 1, or 2; n2 is 1 or 2, A 1 represents a hydrogen atom or a hydroxy group, A 2 is -CH(R 0 )-A 4 indicates a group, R 0 represents a hydrogen atom, a phenyl group optionally substituted with one to three hydroxy groups, or a benzodioxole group, A 3 , and A 4 represent the same or different monovalent organic groups. It is a partial structure shown below.

[0009] Examples of the optionally substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 1-ethyl-n-butyl group, a 2-methyl ... -propyl, cyclopentyl, 1-methylcyclobutyl, 2-methylcyclobutyl, 3-methylcyclobutyl, 1,2-dimethylcyclopropyl, 2,3-dimethylcyclopropyl, 1-ethylcyclopropyl, 2-ethylcyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl , 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,Examples include a 3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-1-methyl-cyclopropyl group, a 2-ethyl-2-methyl-cyclopropyl group, and a 2-ethyl-3-methyl-cyclopropyl group.

[0010] Examples of the aryl group having 6 to 40 carbon atoms include a phenyl group, an o-methylphenyl group, a m-methylphenyl group, a p-methylphenyl group, an o-chlorophenyl group, a m-chlorophenyl group, a p-chlorophenyl group, an o-fluorophenyl group, a p-fluorophenyl group, an o-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, a p-cyanophenyl group, an α-naphthyl group, a β-naphthyl group, an o-biphenylyl group, a m-biphenylyl group, a p-biphenylyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group.

[0011] Substituents for these alkyl and aryl groups include, but are not limited to, halogen atoms (fluorine, chlorine, bromine, iodine), nitro groups, cyano groups, amino groups, hydroxy groups, carbonyl groups, and carbonyloxy groups.

[0012] In formula (1), n1 is preferably 0 and n2 is preferably 1.

[0013] In formula (1), preferably R 1 and R 2 are the same or different and each represents a hydrogen atom or a methyl group. More preferably, R 1 and R 2 are both hydrogen atoms.

[0014] [Monovalent organic group] The monovalent organic group is not particularly limited. It may be derived from various polymers or oligomers, or may be derived from a low molecular weight compound. The monovalent organic group may be derived from a compound represented by formula (1). In particular, A 4represents a compound represented by formula (1), the same or different compounds represented by formula (1) may be -CH(R 0 )-groups.

[0015] [Monovalent organic groups derived from polymers] By employing an organic group derived from a polymer, it is possible to adjust the dry etching rate (amount of film thickness reduction per unit time), attenuation coefficient, refractive index, etc. of the resist underlayer film formed from the protective film-forming composition of the present invention. The polymer is not particularly limited, and various organic polymers can be used, such as addition polymerization polymers, condensation polymerization polymers, and ring-opening polymerization polymers, including polyester, polystyrene, polyimide, acrylic polymer, methacrylic polymer, polyvinyl ether, phenol novolac, naphthol novolac, polyether, polyamide, and polycarbonate.

[0016] Examples of such organic polymers include addition polymerization polymers containing, as structural units, addition-polymerizable monomers such as benzyl acrylate, benzyl methacrylate, phenyl acrylate, naphthyl acrylate, anthryl methacrylate, anthrylmethyl methacrylate, styrene, hydroxystyrene, benzyl vinyl ether, and N-phenylmaleimide, and condensation polymerization polymers such as phenol novolac and naphthol novolac.

[0017] When an addition polymer is used as the organic polymer, the polymer may be a homopolymer or a copolymer. An addition polymerizable monomer is used to produce the addition polymer. Examples of such addition polymerizable monomers include acrylic acid, methacrylic acid, acrylic acid ester compounds, methacrylic acid ester compounds, acrylamide compounds, methacrylamide compounds, vinyl compounds, styrene compounds, maleimide compounds, maleic anhydride, and acrylonitrile.

[0018] Examples of the acrylic acid ester compound include methyl acrylate, ethyl acrylate, normal hexyl acrylate, isopropyl acrylate, cyclohexyl acrylate, benzyl acrylate, phenyl acrylate, anthrylmethyl acrylate, 2-hydroxyethyl acrylate, 3-chloro-2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trichloroethyl acrylate, 2-bromoethyl acrylate, 4-hydroxybutyl acrylate, 2-methoxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-methyl-2-adamantyl acrylate, 5-acryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone, 3-acryloxypropyltriethoxysilane, and glycidyl acrylate.

[0019] Examples of the methacrylic acid ester compound include methyl methacrylate, ethyl methacrylate, normal hexyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, anthrylmethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,2-trichloroethyl methacrylate, 2-bromoethyl methacrylate, 4-hydroxybutyl methacrylate, 2-methoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 2-methyl-2-adamantyl methacrylate, 5-methacryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone, 3-methacryloxypropyltriethoxysilane, glycidyl methacrylate, 2-phenylethyl methacrylate, hydroxyphenyl methacrylate, and bromophenyl methacrylate.

[0020] Examples of the acrylamide compound include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-benzylacrylamide, N-phenylacrylamide, N,N-dimethylacrylamide, and N-anthrylacrylamide.

[0021] Examples of the methacrylamide compound include methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-benzylmethacrylamide, N-phenylmethacrylamide, N,N-dimethylmethacrylamide, and N-anthrylacrylamide.

[0022] Examples of the vinyl compound include vinyl alcohol, 2-hydroxyethyl vinyl ether, methyl vinyl ether, ethyl vinyl ether, benzyl vinyl ether, vinyl acetate, vinyltrimethoxysilane, 2-chloroethyl vinyl ether, 2-methoxyethyl vinyl ether, vinylnaphthalene, and vinylanthracene.

[0023] Examples of the styrene compound include styrene, hydroxystyrene, chlorostyrene, bromostyrene, methoxystyrene, cyanostyrene, and acetylstyrene.

[0024] Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, and N-hydroxyethylmaleimide.

[0025] When a condensation polymerization polymer is used as the polymer, examples of such a polymer include a condensation polymerization polymer of a glycol compound and a dicarboxylic acid compound.

[0026] Examples of the glycol compound include diethylene glycol, hexamethylene glycol, and butylene glycol.

[0027] Examples of the dicarboxylic acid compound include aliphatic dicarboxylic acids and aromatic dicarboxylic acids such as succinic acid, 2,2-dimethylsuccinic acid, adipic acid, terephthalic acid, isophthalic acid, phthalic acid, 3,3'-dithiodipropionic acid, tartaric acid, malic acid, and maleic anhydride.

[0028] Other examples include polyesters, polyamides, and polyimides such as polypyromellitimide, poly(p-phenylene terephthalamide), polybutylene terephthalate, and polyethylene terephthalate.

[0029] When a ring-opening polymer is used as the polymer, examples of such a polymer include a condensation polymerization polymer of a diepoxy compound and a dicarboxylic acid compound.

[0030] Examples of the diepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and compounds represented by the following formulas [3-1] to [3-16]: [ka] [ka] Compounds such as the following can be mentioned.

[0031] Examples of the dicarboxylic acid compound include the dicarboxylic acid compounds described above.

[0032] The polymer that can be used has a weight average molecular weight of, for example, 1,000 to 100,000, or 1,500 to 50,000, or 2,000 to 30,000, or 3,000 to 20,000.

[0033] Preferably, the polymer has the formula (10): [ka] (In formula (10), A represents a direct bond or -C(=O)-, and Ar represents a benzene ring, naphthalene ring, or anthracene ring optionally substituted with an alkyl group having 1 to 6 carbon atoms, a halogen atom, a hydroxy group, a carboxyl group, an amino group, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, a cyano group, an acetyl group, an acetyloxy group, an alkoxycarbonyl group having 1 to 6 carbon atoms, a nitro group, a nitroso group, an amido group, an imido group, an alkoxysulfonyl group having 1 to 6 carbon atoms, or a sulfonamide group.)

[0034] In addition, examples of the alkyl group in formula (10) include a methyl group, an ethyl group, an n-butyl group, a t-butyl group, an isopropyl group, and a cyclohexyl group; examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; examples of the alkoxy group include a methoxy group, an ethoxy group, and a butoxy group; examples of the alkylthio group include a methylthio group, an ethylthio group, and a butylthio group; examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and an isopropoxycarbonyl group; and examples of the alkoxysulfonyl group include a methoxysulfonyl group and an ethoxysulfonyl group.

[0035] The above polymer can be produced by the method described in Japanese Patent No. 5041175, for example.

[0036] [Monovalent organic groups derived from low molecular weight compounds] The low molecular weight compound from which the monovalent organic group is derived is not particularly limited, but considering the risk of volatilization during firing, it is preferable that the molecular weight be 300 or more. The upper limit of the molecular weight is, for example, 999. Some preferred specific examples are as follows. * represents a bond. [ka] [ka] [ka] [ka] [ka] [ka]

[0037] The monovalent organic group may be the above-mentioned low molecular weight compound to which a spacer has been added. Examples of spacers are -CH-, -(CH2) n Examples thereof include one or a combination of two or more of -(n=1 to 20), -CH=CH-, -CH≡CH-, -N=N-, -NH-, -NHR-, -NHCO-, -NRCO-, -S-, -COO-, -O-, -CO-, -CH=N-, -CH(OH)- and phenylene. Two or more of these spacers may be linked together.

[0038] [Specific examples of preferred compounds having a partial structure represented by formula (1)] Examples of preferred compounds having the partial structure represented by formula (1) are as follows:

[0039] Examples of the polymer having the partial structure represented by formula (1) include structural units represented by the following formulae (A-1) to (A-6). [ka]

[0040] The polymer having the partial structure represented by formula (1) may be a copolymer further having structural units represented by the following formulae (A-7) to (A-18). [ka]

[0041] The molar ratio of the polymer having the partial structure represented by formula (1) to the entire polymer, which is occupied by the unit structure having the partial structure represented by formula (1), is 1 to 100 mol %, and preferably 10 to 100 mol %. The unit structure having the partial structure represented by formula (1) may be of one type or two or more types. When the polymer is a copolymer having a unit structure having a partial structure other than that represented by formula (1), the molar ratio is the remainder of the portion occupied by the unit structure having the partial structure represented by formula (1) relative to the entire copolymer, and the unit structure having the partial structure other than that represented by formula (1) may be of one type or two or more types.

[0042] Further, an example of a compound or polymer having the partial structure represented by formula (1) is a reaction product (D) obtained from an epoxy compound or resin represented by formula (B) below and a proton-generating compound having the partial structure represented by formula (1) above, represented by formula (C) below.

[0043] Examples of the epoxy compound (B) include glycidyl ether compounds, glycidyl ester compounds, glycidyl group-containing isocyanurates, epoxycyclohexyl compounds, epoxy group-substituted cyclohexyl compounds, and resins thereof. Examples of the epoxy compound (B) used in the present invention include the following: [ka]

[0044] Formula (B-1) is available from Nissan Chemical Industries, Ltd. under the trade name TEPIC-SS. Formula (B-2) is available from Shikoku Chemicals Corporation under the trade name MA-DGIC. The compound of formula (B-3) is available from Nagase Chemtec Corporation under the trade name EX-411. The compound of formula (B-4) is available from Nagase Chemtec Corporation under the trade name EX-521. The compound of formula (B-7) is available from Nippon Kayaku Co., Ltd. under the trade name RE-810NM. Formula (B-8) is available from Showa Denko KK under the trade name BATG. The compound of formula (B-9) is available from Nagase Chemtec Corporation under the trade name EX-711. Formula (B-10) is available from DIC Corporation under the trade name YD-4032D. Formula (B-11) is available from DIC Corporation under the trade name HP-4770. Formula (B-12) is available from Nippon Steel & Sumikin Chemical Co., Ltd. under the trade name YH-434L. Formula (B-13) is available from DIC Corporation under the trade name EPICLON HP-4700. The compound of formula (B-14) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TEP-G. Formula (B-15) is a product name Epolead GT401 manufactured by Daicel Corporation, a, b, c, and d are each 0 or 1, and a+b+c+d=1. The compound represented by formula (B-16) is available from Daicel Corporation under the trade name EHPE-3150. Formula (B-17) is available from DIC Corporation under the trade name HP-7200L. The compound of formula (B-18) is available from Nippon Kayaku Co., Ltd. under the trade name EPPN-201. Formula (B-19) is available from Asahi Kasei Epoxy Corporation under the trade name ECN-1229. Formula (B-20) is available from Nippon Kayaku Co., Ltd. under the trade name EPPN-501H. The compound of formula (B-21) is available from Nippon Kayaku Co., Ltd. under the trade name NC-2000L. Formula (B-22) is available from Nippon Kayaku Co., Ltd. under the trade name NC-3000L. Formula (B-23) is available from Nippon Kayaku Co., Ltd. under the trade name NC-7000L. The compound of formula (B-24) is available from Nippon Kayaku Co., Ltd. under the trade name NC-7300L. Formula (B-25) is available from Nippon Kayaku Co., Ltd. under the trade name NC-3500. Formula (B-26) is available from DIC Corporation under the trade name EPICLON HP-5000. Formula (B-27) is available from Nippon Kayaku Co., Ltd. under the trade name FAE-2500. The compound of formula (B-28) is available from Nippon Kayaku Co., Ltd. under the trade name NC-6000.

[0045] Examples of the proton-generating compound (C) having the partial structure represented by the formula (1) include the following: Preferably, it is 5-hydroxy-1,3-benzodioxole (sesamol) or piperonylic acid. [ka]

[0046] Specific examples of the reactant (D) having the partial structure represented by the formula (1) include, but are not limited to, the following. [ka]

[0047] Further, examples of the compound or polymer having the partial structure represented by formula (1) include a novolak resin (E) obtained from a phenolic hydroxyl group-containing compound or aromatic amine and an aldehyde having the partial structure represented by formula (1), or from a phenolic hydroxyl group-containing compound having the partial structure represented by formula (1) and an aldehyde.

[0048] The aldehyde having the partial structure represented by the formula (1) is preferably heliotropine (piperonal), and the phenolic hydroxyl group-containing compound having the partial structure represented by the formula (1) is preferably 5-hydroxy-1,3-benzodioxole (sesamol).

[0049] Specific examples of the reactant (E) having the partial structure represented by the formula (1) include, but are not limited to, the following. [ka] [ka]

[0050] [Crosslinking agent] The resist underlayer film-forming composition of the present invention may contain a crosslinker component. Examples of such crosslinkers include melamine-based crosslinkers, substituted urea-based crosslinkers, and polymers thereof. A crosslinker having at least two crosslink-forming substituents is preferred, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensates of these compounds may also be used.

[0051] Furthermore, a crosslinking agent with high heat resistance can be used as the crosslinking agent, such as a compound containing a crosslink-forming substituent with an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule.

[0052] This compound may be a compound having a partial structure of the following formula (5-1), or a polymer or oligomer having a repeating unit of the following formula (5-2). [ka] Above R 11 , R 12 , R 13 , and R 14 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl groups mentioned above can be used. m1 is 1≦m1≦6−m2, m2 is 1≦m2≦5, m3 is 1≦m3≦4−m2, and m4 is 1≦m4≦3.

[0053] Examples of the compounds, polymers and oligomers of formula (5-1) and formula (5-2) are shown below. [ka] [ka]

[0054] The above compounds are available as products of Asahi Organic Chemicals Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above crosslinking agents, the compound of formula (6-22) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TMOM-BP.

[0055] [Crosslinking catalyst] The protective film-forming composition of the present invention may contain, as an optional component, a crosslinking catalyst to promote the crosslinking reaction. The crosslinking catalyst may be an acidic compound, a basic compound, or a compound that generates an acid or a base upon heating, but a crosslinking acid catalyst is preferred. The acidic compound may be a sulfonic acid compound or a carboxylic acid compound, and the compound that generates an acid upon heating may be a thermal acid generator.

[0056] Examples of sulfonic acid compounds or carboxylic acid compounds include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium trifluoromethanesulfonate, pyridinium-p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, pyridinium-4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, 4-nitrobenzenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

[0057] Examples of thermal acid generators include K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, and TAG2689 (all manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (all manufactured by Sanshin Chemical Industry Co., Ltd.).

[0058] These crosslinking catalysts can be used alone or in combination of two or more. As the basic compound, an amine compound or an ammonium hydroxide compound can be used, and as the compound that generates a base by heat, urea can be used.

[0059] Examples of amine compounds include tertiary amines such as triethanolamine, tributanolamine, trimethylamine, triethylamine, tri-normal propylamine, triisopropylamine, tri-normal butylamine, tri-tert-butylamine, tri-normal octylamine, triisopropanolamine, phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, and aromatic amines such as pyridine and 4-dimethylaminopyridine. Other examples of amine compounds include primary amines such as benzylamine and normal butylamine, and secondary amines such as diethylamine and di-normal butylamine. These amine compounds can be used alone or in combination.

[0060] Examples of ammonium hydroxide compounds include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, cetyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, and phenyltriethylammonium hydroxide.

[0061] Examples of compounds that generate a base upon heating include compounds that have a thermolabile group such as an amide group, a urethane group, or an aziridine group and generate an amine upon heating. Other examples of compounds that generate a base upon heating include urea, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylphenylammonium chloride, benzyldodecyldimethylammonium chloride, benzyltributylammonium chloride, and choline chloride.

[0062] When the protective film-forming composition contains a crosslinking catalyst, the content of the crosslinking catalyst is 0.0001 to 20% by weight, preferably 0.01 to 15% by weight, and more preferably 0.1 to 10% by weight, based on the total solid content of the protective film-forming composition.

[0063] [Surfactants] The protective film-forming composition of the present invention may contain a surfactant as an optional component to improve its coatability on semiconductor substrates. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, and polyoxyethylene sorbitan monostearate; nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan trioleate and polyoxyethylene sorbitan tristearate; fluorine-containing surfactants such as F-TOP (registered trademark) EF301, EF303, and EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Megafac (registered trademark) F171, F173, R-30, R-30N, R-40, and R-40-LM (manufactured by DIC Corporation), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited), Asahiguard (registered trademark) AG710, Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). These surfactants can be used alone or in combination of two or more. When the protective film-forming composition contains a surfactant, the content thereof is 0.0001 to 10 wt %, preferably 0.01 to 5 wt %, based on the total solid content of the protective film-forming composition.

[0064] [solvent] The protective film-forming composition of the present invention can be prepared by dissolving the above-mentioned components in an organic solvent, and is used in the form of a homogeneous solution.

[0065] The solvent for the protective film-forming composition of the present invention is not particularly limited, as long as it can dissolve the compound containing at least one pair of two adjacent hydroxyl groups in the molecule, or a polymer thereof. In particular, since the protective film-forming composition of the present invention is used in the form of a homogeneous solution, it is recommended to use a solvent commonly used in lithography processes in combination with the composition, taking into account its coating performance.

[0066] Examples of the organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Examples of the solvent include cyclopentane, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0067] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, etc. are preferred, with propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate being particularly preferred.

[0068] [Other ingredients] The protective film-forming composition of the present invention may contain a light absorber, a rheology modifier, an adhesion promoter, etc. The rheology modifier is effective in improving the fluidity of the protective film-forming composition. The adhesion promoter is effective in improving the adhesion between the semiconductor substrate or resist and the underlayer film.

[0069] Examples of the light-absorbing agent include commercially available light-absorbing agents described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as CI Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; CI Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; CI Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; CI Disperse Violet 43; CI Disperse Blue 96; and CI Fluorescent Brightening Agent. Suitable examples of light-absorbing agents that can be used include CI Solvent Orange 2 and 45, CI Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49, CI Pigment Green 10, and CI Pigment Brown 2. The light-absorbing agent is typically blended in an amount of 10% by mass or less, and preferably 5% by mass or less, based on the total solid content of the protective film-forming composition.

[0070] Rheology modifiers are added primarily to improve the fluidity of the protective film-forming composition, particularly during the baking process, to improve the film thickness uniformity of the resist underlayer film and the ability of the protective film-forming composition to fill holes. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically incorporated in an amount of less than 30% by mass based on the total solids content of the protective film-forming composition.

[0071] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the protective film-forming composition, and particularly to prevent the resist from peeling off during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylmethylolchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylmethylolethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; methyloltrimethylsilane; and methyloltrimethylsilane. Examples of suitable adhesion promoters include silanes such as chlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters are typically blended in an amount of less than 5% by mass, and preferably less than 2% by mass, based on the total solids content of the protective film-forming composition.

[0072] [Protective film forming composition] The solids content of the protective film-forming composition according to the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solids content is the content of all components of the protective film-forming composition excluding the solvent. The proportion of polymer in the solids content is preferably 1 to 100% by mass, 1 to 99.9% by mass, 50 to 99.9% by mass, 50 to 95% by mass, and 50 to 90% by mass, in that order.

[0073] [Method of manufacturing a substrate with a resist pattern and a semiconductor device] Hereinafter, a method for producing a substrate having a resist pattern and a method for producing a semiconductor device using the protective film-forming composition according to the present invention will be described.

[0074] The substrate having a resist pattern according to the present invention can be produced by applying the above-described protective film-forming composition onto a semiconductor substrate and baking it. Examples of semiconductor substrates to which the protective film-forming composition of the present invention can be applied include silicon wafers, germanium wafers, and wafers of compound semiconductors such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride. When a semiconductor substrate having an inorganic film formed on its surface is used, the inorganic film can be formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum deposition, or spin-coating (spin-on-glass: SOG). Examples of the inorganic film include polysilicon film, silicon oxide film, silicon nitride film, BPSG (Boro-Phospho Silicate Glass) film, titanium nitride film, titanium nitride oxide film, tungsten film, gallium nitride film, and gallium arsenide film.

[0075] The protective film-forming composition of the present invention is applied to such a semiconductor substrate using an appropriate application method such as a spinner or coater. A protective film is then formed by baking using a heating means such as a hot plate. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 120°C to 350°C and the baking time is 0.5 to 30 minutes, more preferably, the baking temperature is 150°C to 300°C and the baking time is 0.8 to 10 minutes. The thickness of the formed protective film is, for example, 0.001 μm to 10 μm, preferably 0.002 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm. If the baking temperature is lower than the above range, crosslinking may be insufficient, and the formed protective film may not be resistant to resist solvents or basic hydrogen peroxide aqueous solutions. On the other hand, if the baking temperature is higher than the above range, the protective film may be thermally decomposed.

[0076] Exposure is performed through a mask (reticle) to form a desired pattern. For example, i-line, KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet), or EB (electron beam) is used. An alkaline developer is used for development, with the development temperature selected from 5°C to 50°C and the development time selected from 10 to 300 seconds. Examples of alkaline developers include aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and cyclic amines such as pyrrole and piperidine. Furthermore, the aqueous solutions of these alkalis may be used by adding an appropriate amount of alcohols such as isopropyl alcohol or a nonionic surfactant. Among these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants and the like can be added to these developers. Alternatively, development can be carried out with an organic solvent such as butyl acetate instead of an alkaline developer to develop the portions of the photoresist where the alkaline dissolution rate is not improved.

[0077] Next, the protective film is dry-etched using the formed resist pattern as a mask, to expose the surface of the inorganic film if the inorganic film is formed on the surface of the semiconductor substrate used, or to expose the surface of the semiconductor substrate if the inorganic film is not formed on the surface of the semiconductor substrate used.

[0078] Furthermore, the protective film after dry etching (and the resist pattern if any remains on the protective film) is used as a mask to perform wet etching using a semiconductor wet etching solution, thereby forming a desired pattern. As the semiconductor wet etching solution, a general chemical solution for etching semiconductor wafers can be used, and for example, either an acidic substance or a basic substance can be used. Examples of substances that exhibit acidity include hydrogen peroxide, hydrofluoric acid, ammonium fluoride, acidic ammonium fluoride, ammonium hydrogen fluoride, buffered hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and mixtures thereof. Examples of substances that exhibit basicity include basic hydrogen peroxide solution, which is obtained by mixing ammonia, sodium hydroxide, potassium hydroxide, sodium cyanide, potassium cyanide, or an organic amine such as triethanolamine with hydrogen peroxide solution to make the pH basic. A specific example is SC-1 (ammonia-hydrogen peroxide solution). Other substances that can make the pH basic, such as a mixture of urea and hydrogen peroxide solution, which is heated to cause the urea to thermally decompose, generating ammonia and ultimately making the pH basic, can also be used as wet etching chemicals. Among these, acidic hydrogen peroxide solution or basic hydrogen peroxide solution is preferred, and basic hydrogen peroxide solution is particularly preferred. These chemical solutions may contain additives such as surfactants. The temperature of the semiconductor wet etching solution is preferably 25° C. to 90° C., and more preferably 40° C. to 80° C. The wet etching time is preferably 0.5 to 30 minutes, and more preferably 1 to 20 minutes. [Example]

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The apparatus used to measure the weight-average molecular weight of the polymers obtained in the following synthesis examples is shown below. Apparatus: Tosoh Corporation HLC-8320GPC GPC column: Shodex (registered trademark) Asahipak (registered trademark) (Showa Denko K.K.) Column temperature: 40℃ Flow rate: 0.6mL / min Eluent: N,N-dimethylformamide (DMF) Standard sample: Polystyrene (Tosoh Corporation)

[0080] Example 1 A solution of 16.00 g of glycidyl methacrylate, 4.53 g of 2,2'-azobis(isobutyronitrile), and 65.68 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 16.48 g of propylene glycol monomethyl ether at 100 °C under a nitrogen atmosphere, followed by heating and stirring for 13 hours. To 30.00 g of the resulting solution (epoxy value 676 g / eq), 5.72 g of piperonylic acid, 0.32 g of ethyltriphenylphosphonium bromide, and 20.04 g of propylene glycol monomethyl ether were added, and the mixture was heated and stirred under reflux for 20 hours under a nitrogen atmosphere. To the resulting solution, 11 g of cation exchange resin (Dowex® 550A, Muromachi Technos Co., Ltd.) and 11 g of anion exchange resin (Amberlite® 15JWET, Organo Corporation) were added, and the mixture was subjected to ion exchange treatment at room temperature for 4 hours. By separating the ion exchange resin, a resin solution corresponding to formula (X-1) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 4100.

[0081] [ka]

[0082] To 4.59 g of the obtained resin solution (solid content 17.93 wt%), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries Co., Ltd.) as a crosslinking acid catalyst, 0.001 g of surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorosurfactant), 8.79 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate were added to prepare a solution of a protective film-forming composition.

[0083] <Example 2> A solution of 5.50 g of glycerin monomethacrylate (product name: Blenmer GLM, manufactured by NOF Corporation), 5.09 g of 5-vinylbenzo[d][1,3]dioxole (manufactured by Cool Pharm Ltd.), 0.66 g of 2,2'-azobis(isobutyronitrile), and 35.99 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 9.00 g of propylene glycol monomethyl ether at 100 °C under a nitrogen atmosphere. The resulting solution was heated and stirred for 17 hours. 11 g of a cation exchange resin (product name: Dowex (registered trademark) 550A, manufactured by Muromachi Technos Co., Ltd.) and 11 g of an anion exchange resin (product name: Amberlite (registered trademark) 15JWET, manufactured by Organo Corporation) were added to the resulting solution, and the mixture was subjected to ion exchange treatment at room temperature for 4 hours. By separating the ion exchange resin, a resin solution corresponding to formula (X-2) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 10,800.

[0084] [ka]

[0085] To 5.10 g of the obtained resin solution (solid content 16.12 wt%), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries) as a crosslinking acid catalyst, 0.001 g of surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorosurfactant), 8.27 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate were added to prepare a solution of a protective film-forming composition.

[0086] Example 3 A solution of 5.00 g of glycidyl methacrylate, 5.21 g of 5-vinylbenzo[d][1,3]dioxole (Cool Pharm LTD.), 0.58 g of 2,2'-azobis(isobutyronitrile), and 34.53 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 8.63 g of propylene glycol monomethyl ether at 100 °C under a nitrogen atmosphere. The mixture was heated and stirred for 20 hours. To the resulting solution, 11 g of a cation exchange resin (product name: Dowex [registered trademark] 550A, Muromachi Technos Co., Ltd.) and 11 g of an anion exchange resin (product name: Amberlite [registered trademark] 15JWET, Organo Corporation) were added, and the mixture was subjected to ion exchange treatment at room temperature for 4 hours. The ion exchange resin was separated to obtain a resin solution corresponding to formula (X-3). The weight average molecular weight (Mw) measured by GPC in terms of polystyrene was 9000.

[0087] [ka]

[0088] To 4.74 g of the obtained resin solution (solid content 17.35 wt%), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries Co., Ltd.) as a crosslinking acid catalyst, 0.001 g of surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorosurfactant), 8.64 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate were added to prepare a solution of a protective film-forming composition.

[0089] <Comparative Example 1> A solution of a protective film-forming composition was prepared by adding 0.82 g of polyparahydroxystyrene (product name: VP-8000, manufactured by Nippon Soda Co., Ltd.), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries) as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorine-based surfactant), 12.56 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate.

[0090] <Comparative Example 2> A solution of 14.00 g of 4-hydroxyphenyl methacrylate (product name: PQMA, manufactured by Showa Denko K.K.), 1.13 g of 2,2'-azobis(isobutyronitrile), and 42.37 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 18.16 g of propylene glycol monomethyl ether at 100 °C under a nitrogen atmosphere. The mixture was heated and stirred for 14 hours. To the resulting solution, 15 g of a cation exchange resin (product name: Dowex (registered trademark) 550A, manufactured by Muromachi Technos Co., Ltd.) and 15 g of an anion exchange resin (product name: Amberlite (registered trademark) 15JWET, manufactured by Organo Corporation) were added, and the mixture was subjected to ion exchange treatment at room temperature for 4 hours. The ion exchange resin was separated to obtain a resin solution corresponding to formula (Y-1). The weight average molecular weight (Mw) measured by GPC in terms of polystyrene was 11,000.

[0091] [ka]

[0092] 4.47 g of the obtained resin solution (solid content 18.41% by weight), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries Co., Ltd.) as a crosslinking acid catalyst, 0.001 g of surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorosurfactant), 8.91 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate were added to prepare a solution of a protective film-forming composition.

[0093] <Comparative Synthesis Example 3> A solution of 16.00 g of glycidyl methacrylate, 4.53 g of 2,2'-azobis(isobutyronitrile), and 65.68 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 16.48 g of propylene glycol monomethyl ether at 100°C under a nitrogen atmosphere, followed by heating and stirring for 13 hours. To 30.00 g of the resulting solution (epoxy value 676 g / eq), 5.31 g of 3,4-dihydroxybenzoic acid, 0.20 g of benzyltriethylammonium chloride, and 17.89 g of propylene glycol monomethyl ether were added, and the mixture was heated and stirred under reflux under a nitrogen atmosphere for 20 hours. To the resulting solution, 11 g of a cation exchange resin (product name: Dowex (registered trademark) 550A, Muromachi Technos Co., Ltd.) and 11 g of an anion exchange resin (product name: Amberlite (registered trademark) 15JWET, Organo Corporation) were added, and the mixture was subjected to ion exchange treatment at room temperature for 4 hours. The ion exchange resin was separated to obtain a resin solution corresponding to formula (Y-2). The weight average molecular weight Mw measured by GPC in terms of polystyrene was 24,400.

[0094] [ka]

[0095] To 4.47 g of the obtained resin solution (solid content 19.51 wt%), 0.21 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.02 g of K-PURE TAG-2689 (manufactured by King Industries Co., Ltd.) as a crosslinking acid catalyst, 0.001 g of surfactant (manufactured by DIC Corporation, product name: Megafac [trade name] R-40, fluorosurfactant), 9.16 g of propylene glycol monomethyl ether, and 1.40 g of propylene glycol monomethyl ether acetate were added to prepare a solution of a protective film-forming composition.

[0096] [Resist Solvent Resistance Test] Each of the protective film-forming compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was applied (spin coated) onto a silicon wafer using a spin coater. The coated silicon wafer was heated on a hot plate at 215°C for 1 minute to form a coating (protective film) with a thickness of 200 nm. Next, to confirm the resist solvent resistance of the protective film, the silicon wafer on which the protective film had been formed was immersed for 1 minute in a solvent mixture of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate in a weight ratio of 7:3, spin-dried, and then baked at 100°C for 30 seconds. The thickness of the protective film before and after immersion in the mixed solvent was measured using an optical interference film thickness meter. Resist solvent resistance was evaluated by calculating the percent reduction in thickness of the protective film removed by solvent immersion using the formula: ((film thickness before solvent immersion) - (film thickness after solvent immersion)) ÷ (film thickness before solvent immersion) × 100. A film thickness reduction rate of approximately 1% or less is considered to be within the acceptable range.

[0097] [Table 1]

[0098] From the above results, Examples 1 to 3 and Comparative Examples 1 to 3 showed very little change in film thickness even after immersion in the resist solvent, demonstrating good resist solvent resistance. Therefore, all examples have sufficient resist solvent resistance to function as a protective film.

[0099] [Basic hydrogen peroxide resistance test] To evaluate resistance to basic hydrogen peroxide solution, the protective film-forming compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3, which showed good resist solvent resistance in the resist solvent resistance test, were applied to a 50 nm-thick TiN-deposited substrate and heated at 215°C for 1 minute to form a 200 nm-thick film. Next, 28% ammonia water, 33% hydrogen peroxide, and water were mixed in a weight ratio of 1:1:2 to prepare basic hydrogen peroxide solution. The TiN-deposited substrate coated with the protective film-forming composition was immersed in this basic hydrogen peroxide solution heated to 50°C, and the time from immersion until the protective film peeled from the substrate was measured. The results are shown in Table 2.

[0100] [Table 2]

[0101] The above results indicate that the coating films of Examples 1 to 3 are less likely to peel off from the substrate in the presence of basic hydrogen peroxide than those of Comparative Examples 1 to 3. That is, Examples 1 to 3 exhibit better chemical resistance to basic hydrogen peroxide than Comparative Examples 1 to 3, and are useful as protective films against basic hydrogen peroxide. [Industrial Applicability]

[0102] According to the present invention, it is possible to provide a composition for forming a protective film that has excellent resistance to the basic hydrogen peroxide aqueous solution used in RCA cleaning in the lithography process of semiconductor manufacturing.

Claims

1. A protective film-forming composition for use with a semiconductor wet etching solution selected from an acidic aqueous hydrogen peroxide solution and a basic aqueous hydrogen peroxide solution, the composition comprising: a polymer of a compound containing at least one acetal structure in the molecule, the polymer having a benzodioxole group or a 2,2-dimethylbenzodioxole group in a side chain; and a solvent.

2. The protective film-forming composition according to claim 1 , wherein the polymer is an acrylic polymer or a methacrylic polymer.

3. The protective film-forming composition according to claim 1 or 2, further comprising a crosslinking catalyst.

4. The protective film-forming composition according to claim 1 , further comprising a crosslinking agent.

5. The protective film-forming composition according to claim 1 , further comprising a surfactant.

6. 6. The protective film-forming composition according to claim 1, for producing a resist-patterned substrate for use in the production of semiconductors, comprising a step of applying the composition to a semiconductor substrate and baking the composition to form a protective film as a resist underlayer film.

7. A method for manufacturing a semiconductor device, comprising the steps of: forming a protective film on a semiconductor substrate, on the surface of which an inorganic film may be formed, using a protective film-forming composition for a semiconductor wet etching solution, the protective film comprising a polymer of a compound containing at least one acetal structure in the molecule, the polymer having a 2,2-dimethylbenzodioxole group in a side chain, and a solvent; forming a resist pattern on the protective film; dry-etching the protective film using the resist pattern as a mask to expose a surface of the inorganic film or the semiconductor substrate; and wet-etching and cleaning the inorganic film or the semiconductor substrate using the protective film after dry etching as a mask, The semiconductor wet etching solution is a basic hydrogen peroxide aqueous solution. A method for manufacturing a semiconductor device.

Images