Chemical-resistant protective film

Abstract

To provide a protective film-forming composition having excellent preservation stability and a favorable masking (protection) function against wet etching solutions when processing a semiconductor substrate, and a protective film manufactured using the composition.SOLUTION: A protective film-forming composition against wet etching solutions for semiconductors, comprises a polymer having a unit structure represented by Formula (1-1), a thermal polymerization initiator, and a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a protective film, particularly having excellent resistance to a semiconductor wet etching solution, in a lithography process in semiconductor manufacturing. The present invention also relates 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] 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 to form a resist pattern of a desired shape. After the resist pattern is formed, the substrate is processed, and dry etching is the primary method used for this process, although wet etching may also be used depending on the type of substrate. Patent Documents 1 and 2 disclose protective film-forming compositions for aqueous hydrogen peroxide solutions containing specific compounds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 052130 [Patent Document 2] International Publication No. 2018 / 203464 Summary of the Invention [Problem to be solved by the invention]

[0004] When a resist underlayer film is used as an etching mask to process an underlying substrate by wet etching, the resist underlayer film is required to have a good masking function against the wet etching solution during processing of the underlying substrate (i.e., the masked portion can protect the substrate). In such cases, the resist underlayer film is used as a protective film for the substrate. In the past, a method of adding low molecular weight compounds (e.g., gallic acid) as additives was used to develop resistance to SC-1 (ammonia-hydrogen peroxide solution), a type of wet etching chemical, but this had limitations in solving the above problems. An object of the present invention is to solve the above problems. [Means for solving the problem]

[0005] The present invention encompasses the following. [1] The following formula (1-1): [ka] (In formula (1-1), Ar represents a benzene ring, a naphthalene ring, or an anthracene ring, and R 1 represents a hydroxy group, a mercapto group which may be protected by a methyl group, an amino group which may be protected by a methyl group, a halogeno group, or an alkyl group having 1 to 10 carbon atoms which may be substituted or interrupted by a hetero atom and which may be substituted by a hydroxy group; n1 represents an integer of 0 to 3; n2 represents 1 or 2; L 1 represents a single bond or an alkylene group having 1 to 10 carbon atoms, E represents an epoxy group, and T 1 When n2=1, represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a single bond, an ether bond, an ester bond or an amide bond; T 1 A protective film-forming composition for a semiconductor wet etching solution, comprising a polymer having a unit structure represented by the following formula: (when n2=2, represents a nitrogen atom or an amide bond), a thermal polymerization initiator, and a solvent. [2] The above L 1 However, the following formula (1-2): [ka] (In formula (1-2), R 2 , R 3are each independently a hydrogen atom, 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, or a cyclobutyl group; R 2 , R 3 may be bonded to each other to form a ring having 3 to 6 carbon atoms). [3] The protective film-forming composition for a semiconductor wet etching solution according to [1], wherein the thermal polymerization initiator is a thermal cationic polymerization initiator. [4] The protective film-forming composition for a semiconductor wet etching solution according to [3], wherein the thermal cationic polymerization initiator is an onium salt compound. [5] The protective film-forming composition for a semiconductor wet etching solution according to any one of [1] to [4], wherein the semiconductor wet etching solution contains aqueous hydrogen peroxide. [6] A protective film against a wet etching solution for semiconductors, which is a fired product of a coating film made of the protective film-forming composition according to any one of [1] to [5]. [7]

[0023] A method for producing a substrate having a resist pattern, the method comprising the steps of applying the protective film composition according to any one of [1] to [5] onto a semiconductor substrate and baking it to form a protective film as a resist underlayer film, forming a resist film on the protective film, and then exposing and developing the resist film to form a resist pattern, the method being used in the production of a semiconductor. [8] 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 the protective film-forming composition according to any one of [1] to [5], 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 / or cleaning the inorganic film or the semiconductor substrate using a semiconductor wet etching solution using the protective film after dry etching as a mask. [Effects of the Invention]

[0006] The protective film-forming composition of the present invention has a good masking function against wet etching solutions when processing an underlying substrate in the lithography process of semiconductor manufacturing, thereby facilitating microfabrication of semiconductor substrates. DETAILED DESCRIPTION OF THE INVENTION

[0007] <Protective film forming composition> The protective film-forming composition of the present application comprises a compound represented by the following formula (1-1):

[0008] [ka]

[0009] (In formula (1-1), Ar represents a benzene ring, a naphthalene ring, or an anthracene ring, and R 1 represents a hydroxy group, a mercapto group which may be protected by a methyl group, an amino group which may be protected by a methyl group, a halogeno group, or an alkyl group having 1 to 10 carbon atoms which may be substituted or interrupted by a hetero atom and which may be substituted by a hydroxy group, as a substituent of a hydrogen atom contained in the benzene ring, naphthalene ring, or anthracene ring; n1 represents an integer of 0 to 3; n2 represents 1 or 2; L 1 represents a single bond or an alkylene group having 1 to 10 carbon atoms, E represents an epoxy group, and T 1 When n2=1, represents a single bond or an alkylene group having 1 to 10 carbon atoms which may be interrupted by an ether bond, an ester bond or an amide bond; T 1 represents a nitrogen atom or an amide bond when n2=2), a thermal polymerization initiator, and a solvent.

[0010] Above R 1 may be an alkoxy group having 1 to 10 carbon atoms.

[0011] Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, an s-butoxy group, a t-butoxy group, an n-pentoxy group, a 1-methyl-n-butoxy group, a 2-methyl-n-butoxy group, a 3-methyl-n-butoxy group, a 1,1-dimethyl-n-propoxy group, a 1,2-dimethyl-n-propoxy group, a 2,2-dimethyl-n-propoxy group, a 1-ethyl-n-propoxy group, an n-hexyloxy group, a 1-methyl-n-pentyloxy group, a 2-methyl-n-pentyloxy group, a 3-methyl-n-pentyloxy group, a 4-methyl-n-pentyloxy group, a 5-methyl-n-butoxy group, a 6-methyl-n-butoxy group, a 7-methyl-n-butoxy group, a 8-methyl-n-butoxy group, a 9-methyl-n-butoxy group, a 10-methyl-n-butoxy group, a 11-methyl-n-butoxy group, a 12-methyl-n-butoxy group, a 13-methyl-n-butoxy group, a 14-methyl-n-butoxy group, a 15-methyl-n-butoxy group, a 16-methyl-n-butoxy group, a 17-methyl-n-butoxy group, a 18-methyl-n-butoxy group, a 19-methyl-n-butoxy group, a 20-methyl-n-butoxy group, a 21-methyl-n-butoxy group, a 22-methyl-n-butoxy group, a 23-methyl-n-butoxy group, a 24-methyl-n-butoxy group, a 25-methyl-n-butoxy group, a 26-methyl-n-butoxy group, a Examples of the alkyl group include an ethyl-n-pentyloxy group, a 1,1-dimethyl-n-butoxy group, a 1,2-dimethyl-n-butoxy group, a 1,3-dimethyl-n-butoxy group, a 2,2-dimethyl-n-butoxy group, a 2,3-dimethyl-n-butoxy group, a 3,3-dimethyl-n-butoxy group, a 1-ethyl-n-butoxy group, a 2-ethyl-n-butoxy group, a 1,1,2-trimethyl-n-propoxy group, a 1,2,2-trimethyl-n-propoxy group, a 1-ethyl-1-methyl-n-propoxy group, a 1-ethyl-2-methyl-n-propoxy group, an n-heptyloxy group, an n-octyloxy group, and an n-nonyloxy group.

[0012] The unit structure represented by the formula (1-1) may be one type or a combination of two or more types. For example, a copolymer having a plurality of unit structures in which Ar is the same type may be used, and copolymers having a plurality of unit structures in which Ar is different, such as a unit structure in which Ar contains a benzene ring and a unit structure in which Ar contains a naphthalene ring, are not excluded from the technical scope of the present application.

[0013] The above phrase "optionally interrupted" means, in the case of an alkylene group having 2 to 10 carbon atoms, that any carbon-to-carbon bond in the alkylene group is interrupted by a heteroatom (i.e., an ether bond in the case of oxygen, or a sulfide bond in the case of sulfur), an ester bond, or an amide bond; and in the case of an alkylene group having one carbon atom (i.e., a methylene group), that either one of the carbons of the methylene group has a heteroatom (i.e., an ether bond in the case of oxygen, or a sulfide bond in the case of sulfur), an ester bond, or an amide bond.

[0014] Above T 1 When n2=1, represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a single bond, an ether bond, an ester bond, or an amide bond, and is preferably a combination of an ether bond and a methylene group (i.e., when "-T1-(E)n2" in formula (1-1) is a glycidyl ether group), a combination of an ester bond and a methylene group, or a combination of an amide bond and a methylene group.

[0015] An alkyl group having 1 to 10 carbon atoms which may be substituted with a heteroatom refers to an alkyl group having 1 to 10 carbon atoms in which one or more hydrogen atoms have been substituted with a heteroatom (preferably a halogeno group).

[0016] Examples of the 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, and a 1-ethyl-n-propyl group. group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2 -dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,Examples of such alkyl groups include 3-trimethyl-cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl-2-methyl-cyclopropyl group, 2-ethyl-3-methyl-cyclopropyl group, decyl group, methoxy group, ethoxy group, methoxymethyl group, ethoxymethyl group, methoxyethyl group, ethoxyethyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, methylamino group, dimethylamino group, diethylamino group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, methylthio group, ethylthio group, mercaptomethyl group, 1-mercaptoethyl group, and 2-mercaptoethyl group.

[0017] Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, a cyclopropylene group, an n-butylene group, an isobutylene group, an s-butylene group, a t-butylene group, a cyclobutylene group, a 1-methyl-cyclopropylene group, a 2-methyl-cyclopropylene group, an n-pentylene group, a 1-methyl-n-butylene group, a 2-methyl-n-butylene group, a 3-methyl-n-butylene group, a 1,1-dimethyl-n-propylene group, a 1,2-dimethyl-n-propylene group, a 2,2-dimethyl-n-propylene group, and a 1-ethyl-n-propylene group. propylene, cyclopentylene, 1-methylcyclobutylene, 2-methylcyclobutylene, 3-methylcyclobutylene, 1,2-dimethylcyclopropylene, 2,3-dimethylcyclopropylene, 1-ethylcyclopropylene, 2-ethylcyclopropylene, n-hexylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-pentylene, 4-methyl-n-pentylene, 1,1-dimethyl-n-butylene, 1,2-dimethyl-n-butylene, 1,3-dimethyl-n-butylene , 2,2-dimethyl-n-butylene group, 2,3-dimethyl-n-butylene group, 3,3-dimethyl-n-butylene group, 1-ethyl-n-butylene group, 2-ethyl-n-butylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2-trimethyl-n-propylene group, 1-ethyl-1-methyl-n-propylene group, 1-ethyl-2-methyl-n-propylene group, cyclohexylene group, 1-methyl-cyclopentylene group, 2-methyl-cyclopentylene group, 3-methyl-cyclopentylene group, 1-ethyl-cyclobutylene group, 2-ethyl-cyclobutylene cyclobutylene group, 3-ethylcyclobutylene group, 1,2-dimethylcyclobutylene group, 1,3-dimethylcyclobutylene group, 2,2-dimethylcyclobutylene group, 2,3-dimethylcyclobutylene group, 2,4-dimethylcyclobutylene group, 3,3-dimethylcyclobutylene group, 1-n-propylcyclopropylene group, 2-n-propylcyclopropylene group, 1-isopropylcyclopropylene group, 2-isopropylcyclopropylene group, 1,2,2-trimethylcyclopropylene group, 1,2,3-trimethylcyclopropylene group, 2,2,Examples of the cyclopropylene group include a 3-trimethyl-cyclopropylene group, a 1-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-1-methyl-cyclopropylene group, a 2-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-3-methyl-cyclopropylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, and an n-decanylene group.

[0018] The above L 1 represents a single bond or an alkylene group having 1 to 10 carbon atoms, and is represented by the following formula (1-2):

[0019] [ka]

[0020] (In formula (1-2), R 2 , R 3 are each independently a hydrogen atom, 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, or a cyclobutyl group; R 2 , R 3 may be bonded to each other to form a ring having 3 to 6 carbon atoms). 2 , R 3 Both are hydrogen atoms (i.e., -(CR 2 R 3 )— is preferably a methylene group).

[0021] The above-mentioned halogeno group refers to a halogen -X (F, Cl, Br, I) that replaces hydrogen.

[0022] The polymer is not particularly limited as long as it satisfies the unit structure of formula (1). It may be produced by a method known per se. Commercially available products may also be used. Examples of commercially available products include the heat-resistant epoxy novolac resin EOCN (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.) and the epoxy novolac resin DEN (registered trademark) series (manufactured by Dow Chemical Japan Co., Ltd.).

[0023] The weight average molecular weight of the polymer is 100 or more, 500 to 200,000, 600 to 50,000, or 700 to 10,000.

[0024] The polymer of the present invention may have the following unit structure:

[0025] [ka]

[0026] <Thermal polymerization initiator> The thermal polymerization initiator of the present application is different from so-called photopolymerization initiators and refers to a compound that generates acid predominantly upon heating (for example, 50°C to 300°C) compared to upon irradiation with light. The thermal polymerization initiator of the present application is preferably a thermal cationic polymerization initiator. Specific examples include sulfonic acid compounds and carboxylic acid compounds such as pyridinium p-toluenesulfonate, pyridinium p-hydroxybenzenesulfonate, pyridinium trifluoromethanesulfonate, p-toluenesulfonic acid, p-hydroxybenzenesulfonic acid, trifluoromethanesulfonic acid, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, chlorobenzenesulfonic acid, methyl 4-phenolsulfonate, benzenesulfonic acid, naphthalenesulfonic acid, citric acid, and benzoic acid, and the 4th hydroxybenzoate of trifluoromethanesulfonic acid. ammonium salts such as K-PURE (registered trademark) TAG2689, TAG2690, TAG2678, and CXC-1614 (all manufactured by King Industries), 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, aromatic sulfonium salts such as the San-Aid (registered trademark) SI series (e.g., SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150) (manufactured by Sanshin Chemical Industry Co., Ltd.), and other organic sulfonic acid alkyl esters.

[0027] Among these, onium salt compounds are preferred, quaternary ammonium salt-containing compounds are preferred, and quaternary ammonium salts of trifluoromethanesulfonic acid are preferred. These thermal polymerization initiators may be contained alone or in combination of two or more.

[0028] The content of the thermal acid generator in the protective film-forming composition 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.

[0029] <Solvent> The protective film-forming composition of the present invention can be prepared by dissolving the above-mentioned components in a solvent, preferably an organic solvent, and is used in the form of a homogeneous solution.

[0030] The solvent for the protective film-forming composition of the present invention can be any solvent that can dissolve the components contained in the protective film-forming composition of the present invention that are solid at room temperature. 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 that is commonly used in lithography processes in combination with the composition, taking into account its coating performance.

[0031] 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.

[0032] 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.

[0033] <Crosslinking agent> The protective film-forming composition of the present invention can 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 can also be used.

[0034] 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.

[0035] This compound may be a compound having a partial structure of the following formula (2-1), or a polymer or oligomer having a repeating unit of the following formula (2-2).

[0036] [ka]

[0037] Above R 18 , R 19 , R 20 , and R 21 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl groups mentioned above can be used.

[0038] n3 is 1≦n3≦6−n4, n4 is 1≦n4≦5, n5 is 1≦n5≦4−n6, and n6 is 1≦n6≦3.

[0039] The compounds represented by formula (2-1) are exemplified by the following formulae (2-3) to (2-19).

[0040] [ka]

[0041] 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 (2-15) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TMOM-BP.

[0042] The amount of crosslinking agent added varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 to 80 wt %, preferably 0.01 to 50 wt %, and more preferably 0.1 to 40 wt %, based on the total solids content of the protective film-forming composition. These crosslinking agents may undergo a crosslinking reaction by self-condensation, but when crosslinkable substituents are present in the above-mentioned polymer of the present invention, they can undergo a crosslinking reaction with those crosslinkable substituents.

[0043] <Surfactant> The protective film-forming composition of the present invention may optionally contain a surfactant 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 mono. Examples of suitable surfactants include nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan stearate, 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-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% by weight, preferably 0.01 to 5% by weight, based on the total solid content of the protective film-forming composition.

[0044] <Protective film forming composition> The solid content of the protective film-forming composition according to the present invention is usually 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solid content is the content of all components excluding the solvent from the protective film-forming composition. The proportion of polymer in the solid 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.

[0045] <Wet etching solution for semiconductors> 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] These chemical solutions may contain additives such as surfactants.

[0050] The temperature at which the semiconductor wet etching solution is used 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.

[0051] <Protective film against semiconductor wet etching solution, substrate with resist pattern, and method for manufacturing 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.

[0052] 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.

[0053] 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.

[0054] 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, silicon oxynitride film, BPSG (Boro-Phospho Silicate Glass) film, titanium nitride film, titanium oxynitride film, tungsten nitride film, gallium nitride film, and gallium arsenide film.

[0055] The protective film-forming composition of the present invention is applied onto 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. A baking temperature of 120°C to 350°C and a baking time of 0.5 to 30 minutes are preferred, and a baking temperature of 150°C to 300°C and a baking time of 0.8 to 10 minutes are more preferred. The thickness of the formed protective film is, for example, 0.001 μm to 10 μm, 0.002 μm to 1 μm, 0.005 μm to 0.5 μm (= 5 nm to 500 nm), 10 nm to 300 nm, 15 nm to 200 nm, or 30 to 150 nm. If the baking temperature is lower than the above range, crosslinking may be insufficient, and the formed protective film may not be resistant to the resist solvent or wet etching solution, whereas if the baking temperature is higher than the above range, the protective film may be decomposed by heat.

[0056] The resist pattern is formed through a mask (reticle) for forming a desired pattern. For example, exposure to i-line, KrF excimer laser, ArF excimer laser, or EUV (extreme ultraviolet) light, or EB (electron beam) writing 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 can also be used by adding appropriate amounts of alcohols such as isopropyl alcohol and nonionic surfactants. 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.

[0057] 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. [Example]

[0058] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0059] The apparatus used to measure the weight-average molecular weight of the compounds used in the following examples is shown below. Apparatus: Tosoh Corporation HLC-8320GPC GPC column: Shodex (registered trademark) Asahipak (registered trademark) (Showa Denko K.K.) Column temperature: 40℃ Solvent: tetrahydrofuran (THF) Flow rate: 0.6mL / min Standard sample: Polystyrene (Tosoh Corporation)

[0060] Meaning of symbols; PGME: Propylene glycol monomethyl ether PGMEA: Propylene glycol monomethyl ether acetate

[0061] Example 1 2.00 g of epoxy novolac resin EOCN-104S (a product of Nippon Kayaku Co., Ltd., corresponding to formula (1)) (50 mass % PGMEA solution, weight average molecular weight 3100) was mixed with 2.08 g of K-PURE (registered trademark) TAG-2689 (a product of King Industries) (0.5 mass % PGME solution) as a thermal acid generator, and further with 19.23 g of PGMEA and 6.62 g of PGME as solvents to prepare a 3.5 mass % solution. The solution was filtered using a polytetrafluoroethylene microfilter with a pore size of 0.2 μm to prepare a protective film-forming composition.

[0062] [ka]

[0063] <Example 2> 2.08 g of epoxy novolac resin DEN438 (Dow Chemical Japan, equivalent to formula (2)) (50 wt% PGME solution, weight-average molecular weight: 900) was mixed with 2.08 g of K-PURE (registered trademark) TAG-2689 (King Industries) (0.5 wt% PGME solution) as a thermal acid generator, and 20.27 g of PGMEA and 5.58 g of PGME as solvents to prepare a 3.5 wt% solution. The solution was filtered through a 0.2 μm pore size polytetrafluoroethylene microfilter to prepare the protective film-forming composition.

[0064] [ka]

[0065] <Comparative Example 1> 10.40 g of Epolead GT401 (a product of Daicel Corporation, corresponding to formula (3), weight-average molecular weight 700) (10 wt % PGMEA solution) was mixed with 2.08 g of K-PURE (registered trademark) TAG-2689 (a product of King Industries) (0.5 wt % PGME solution) as a thermal acid generator, and further with 10.91 g of PGMEA and 6.62 g of PGME as solvents to prepare a 3.5 wt % solution. The solution was filtered using a polytetrafluoroethylene microfilter with a pore size of 0.2 μm to prepare a protective film-forming composition.

[0066] [ka]

[0067] <Comparative Example 2> 2.00 g of epoxy novolac resin EOCN-104S (product of Nippon Kayaku Co., Ltd., corresponding to formula (1)) (50 mass % PGMEA solution, weight average molecular weight 3100) was mixed with 0.05 g of triphenylsulfonium trifluoromethanesulfonate (product name TPS105, product of Midori Chemical Co., Ltd.) as a photoacid generator, and further with 19.27 g of PGMEA and 8.69 g of PGME as solvents to prepare a 3.5 mass % solution. The solution was filtered using a polytetrafluoroethylene microfilter with a pore size of 0.2 μm to prepare a protective film-forming composition.

[0068] <Comparative Example 3> 10.00 g of Epolead GT401 (a product of Daicel Corporation, corresponding to formula (3), weight-average molecular weight 700) (10 mass % PGMEA solution) was mixed with 0.05 g of triphenylsulfonium trifluoromethanesulfonate (manufactured by Midori Chemical Co., Ltd., product name TPS105) as a photoacid generator, and further with 11.27 g of PGMEA and 8.69 g of PGME as solvents to prepare a 3.5 mass % solution. The solution was filtered using a polytetrafluoroethylene microfilter with a pore size of 0.2 μm to prepare a protective film-forming composition.

[0069] [Thermosetting test] The protective film-forming compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were each applied to a silicon wafer using a spinner. The resulting coating was then baked on a hot plate at 250°C for 1 minute to form a protective film (90 nm thick). These protective films were immersed for 1 minute in OK73 thinner (manufactured by Tokyo Ohka Kogyo Co., Ltd., a PGME / PGMEA = 7 / 3 mixed solvent), a solvent used in photoresist solutions, to evaluate their resistance to the solvent. Insoluble compositions were marked with an ◯, and soluble compositions were marked with an ×. The results are shown in Table 1.

[0070] [Photocuring test] The protective film-forming compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were each applied to a silicon wafer using a spinner. The resulting coating film was then baked on a hot plate at 100°C for 1 minute to form a protective film (film thickness 90 nm). These protective films were then coated using a 172 nm light irradiation device SUS867 manufactured by Ushio Inc. under a nitrogen atmosphere, irradiating the film with light of a wavelength of 172 nm at approximately 500 mJ / cm. 2 The entire wafer surface was irradiated with light. Furthermore, the wafer was immersed for 1 minute in OK73 thinner (a PGME / PGMEA = 7 / 3 mixed solvent, manufactured by Tokyo Ohka Kogyo Co., Ltd.), a solvent used in photoresist solutions, to evaluate its resistance to the solvent. ○ indicates insolubility, and × indicates dissolution. The results are shown in Table 1.

[0071] [Optical parameter testing] The protective film-forming compositions prepared in Examples 1 and 2 and Comparative Example 1 were applied to a silicon substrate using a spinner. The resulting coating film was then baked on a hot plate at 250°C for 1 minute to form a protective film (thickness 90 nm). Furthermore, the protective film-forming compositions prepared in Comparative Examples 2 and 3 were applied to a silicon substrate using a spinner. The resulting coating film was then baked on a hot plate at 100°C for 1 minute, and 172 nm light was irradiated at approximately 500 mJ / cm2 using a 172 nm light irradiation device SUS867 under a nitrogen atmosphere. 2 The entire surface of the wafer was irradiated with the light to form a protective film (film thickness: 90 nm).

[0072] Next, the refractive index (n value) and extinction coefficient (k value) of these protective films were measured at wavelengths of 193 nm and 248 nm using a spectroscopic ellipsometer (JA Woollam, VUV-VASE VU-302). The results are shown in Table 1.

[0073] [Basic hydrogen peroxide aqueous solution resistance test] The APM resistance of the protective film-forming compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was evaluated immediately after preparation and after storing the solutions at 35° C. for one week.

[0074] The protective film-forming compositions prepared in Examples 1 and 2 and Comparative Example 1 were applied by a spinner onto a silicon substrate having a titanium nitride film formed on its surface. The resulting coating film was then baked on a hot plate at 250°C for 1 minute to form a protective film (thickness: 90 nm). Furthermore, the protective film-forming compositions prepared in Comparative Examples 2 and 3 were applied by a spinner onto a silicon substrate having a titanium nitride film formed on its surface. The resulting coating film was then baked on a hot plate at 100°C for 1 minute, and irradiated with 172 nm light at a rate of approximately 500 mJ / cm2 in a nitrogen atmosphere using a 172 nm light irradiation device SUS867. 2 The entire surface of the wafer was irradiated with the light to form a protective film (film thickness: 90 nm).

[0075] The protective film formed on the silicon substrate was then immersed in a basic hydrogen peroxide aqueous solution (abbreviated as APM in Table 1 below) having the composition shown in Table 2 below at the temperature shown in the same table, and the time until the protective film peeled off from the silicon substrate was measured to evaluate APM resistance. The results are shown in Table 1. In Table 1, "◯" indicates that no peeling of the resist underlayer film was observed after 10 minutes of immersion, and "×" indicates that peeling of part or all of the resist underlayer film was observed after 10 minutes of immersion.

[0076] [Table 1]

[0077] [Table 2]

[0078] The results in Table 1 above show that the protective films formed using the protective film-forming compositions prepared in Examples 1 and 2 and Comparative Example 1 exhibited solvent resistance to resist solvents only upon thermal curing. On the other hand, the protective films formed using the protective film-forming compositions prepared in Comparative Examples 2 and 3 exhibited solvent resistance to resist solvents only upon photocuring. Furthermore, as shown in Table 1, the resin used in the protective film-forming composition of the present invention had superior APM resistance compared to the protective film-forming compositions prepared in Comparative Examples 2 and 3.

[0079] Furthermore, the resin used in the protective film-forming composition of the present invention was found to have superior storage stability compared to the protective film-forming composition prepared in Comparative Example 1. This is thought to be because the protective film-forming composition prepared in Comparative Example 1 had poor storage stability, did not undergo sufficient crosslinking, and did not exhibit APM resistance. [Industrial Applicability]

[0080] The protective film-forming composition according to the present invention provides a protective film that is highly resistant to the application of a wet etching solution in substrate processing.

Claims

1. The following formula (1-1): 【Chemical 1】 (In formula (1-1), Ar represents a benzene ring, a naphthalene ring, or an anthracene ring, and R １ represents a hydroxy group, a mercapto group which may be protected by a methyl group, an amino group which may be protected by a methyl group, a halogeno group, or an alkyl group having 1 to 10 carbon atoms which may be substituted or interrupted by a heteroatom and which may be substituted by a hydroxy group; n1 represents an integer of 0 to 3; n2 represents 1 or 2; L １ represents a single bond or an alkylene group having 1 to 10 carbon atoms, E represents an epoxy group, and T １ When n2=1, represents an alkylene group having 1 to 10 carbon atoms which may be interrupted by a single bond, an ether bond, an ester bond or an amide bond; T １ represents a nitrogen atom or an amide bond when n2=2), a thermal polymerization initiator, and a solvent.

2. The above L １ is expressed by the following formula (1-2): 【Chemistry 2】 (In formula (1-2), R ２ , R ３ are each independently a hydrogen atom, 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, or a cyclobutyl group; R ２ , R ３ The protective film-forming composition for use with a semiconductor wet etching solution according to claim 1, wherein:

3. 2. The protective film-forming composition for a semiconductor wet etching solution according to claim 1, wherein the thermal polymerization initiator is a thermal cationic polymerization initiator.

4. The protective film-forming composition for a semiconductor wet etching solution according to claim 3 , wherein the thermal cationic polymerization initiator is an onium salt compound.

5. 5. The protective film-forming composition for a semiconductor wet etching solution according to claim 1, wherein the semiconductor wet etching solution contains aqueous hydrogen peroxide.

6. A protective film against a semiconductor wet etching solution, which is a fired product of a coating film made of the protective film-forming composition according to any one of claims 1 to 5.

Images