Composition for forming protective film, protective film, method for manufacturing substrate, and method for manufacturing semiconductor device

Abstract

This composition for forming a protective film is for forming a protective film that protects an inorganic film formed on the surface of a semiconductor substrate from being wet etched. The composition comprises: a compound (A) having a substructure represented by formula (A-1) and a substructure represented by formula (A-2); a compound (B) represented by formula (B); and a solvent. In formula (A-1), X1 and X2 are each independently a single bond or a carbonyl group. Q1 represents a divalent organic group having 1-20 carbon atoms. * represents a bond.　In formula (A-2), each A independently represents a hydrogen atom, a methyl group, or an ethyl group. Q2 represents a divalent organic group having 1-20 carbon atoms. * represents a bond. In formula (B), n represents an integer of 2 to 10.　When n is 2, X represents a sulfinyl group, a sulfonyl group, an ether group, or a divalent organic group having 2 to 50 carbon atoms.　When n is an integer other than 2, X represents a n-valent organic group having 2 to 50 carbon atoms.

Description

Composition for forming protective film, protective film, method for manufacturing substrate, and method for manufacturing semiconductor device

[0001] The present invention relates to a composition for forming a protective film, particularly one that is highly resistant to semiconductor wet etching solutions, in a lithography process in semiconductor manufacturing. It also relates to a compound that can be suitably used in the protective film-forming composition. It also relates to a protective film formed from the composition, a method for producing a resist-patterned substrate using the protective film, and a method for producing a semiconductor device.

[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 to be formed thereon, thereby forming a resist pattern of a desired shape. After the resist pattern is formed, the substrate is processed, and dry etching is mainly used as the process, but wet etching may also be used depending on the type of substrate. Patent Document 1 discloses a resist underlayer film material that is resistant to alkaline hydrogen peroxide solution.

[0003] Japanese Patent Application Laid-Open No. 2018-173520

[0004] When a protective film for a semiconductor substrate is formed using a protective film-forming composition and the underlying substrate is processed by wet etching using the protective film as an etching mask, the protective film is required to have a good masking function against a semiconductor wet etching solution (i.e., to be able to protect the masked portion of the substrate) and resistance to the solvent contained in the resist composition (solvent resistance). Furthermore, it is desired that a protective film with a high dry etching rate can be formed, that good coverage is also provided for uneven substrates, that the film thickness difference after filling is small, and that a flat protective film can be formed.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a composition for forming a protective film that can form a protective film that has excellent resistance to solvents contained in resist compositions, and that can form a protective film that has a high etching rate and excellent resistance to semiconductor wet etching solutions. Another aim of the present invention is to provide a protective film formed from the composition for forming a protective film, a method for manufacturing a resist-patterned substrate using the protective film, and a method for manufacturing a semiconductor device.

[0006] As a result of intensive research conducted by the inventors to solve the above-mentioned problems, they discovered that the above-mentioned problems can be solved by adding a specific compound to a composition for forming a protective film, and thus completed the present invention.

[0007] That is, the present invention encompasses the following aspects: [1] A composition for forming a protective film for forming a protective film on a semiconductor substrate having an inorganic film formed on its surface, the protective film protecting the inorganic film from wet etching, the composition for forming a protective film comprising: a compound (A) having a partial structure represented by the following formula (A-1) and a partial structure represented by the following formula (A-2), a compound (B) represented by the following formula (B), and a solvent. (In formula (A-1), X １ and X ２ each independently represents a single bond or a carbonyl group. １ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond. In formula (A-2), each A independently represents a hydrogen atom, a methyl group, or an ethyl group. Q ２ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond. (In formula (B), n represents an integer of 2 to 10. When n is 2, X represents a sulfinyl group, a sulfonyl group, an ether group, or a divalent organic group having 2 to 50 carbon atoms. When n is an integer other than 2, X represents an n-valent organic group having 2 to 50 carbon atoms. Y represents a single bond or a divalent linking group having 1 to 12 carbon atoms.) [2] The composition for forming a protective film according to [1], wherein X in formula (B) is an n-valent organic group having 2 to 50 carbon atoms and having a ring structure. [3] The composition for forming a protective film according to [1] or [2], wherein X in formula (B) is any of the structures represented by the following: (wherein * represents a bond.) [4] The composition for forming a protective film according to any one of [1] to [3], wherein Y in formula (B) is a divalent linking group having 1 to 12 carbon atoms and represented by the following formula (Y-1): (In formula (Y-1), R １ represents a single bond or an alkylene group having 1 to 4 carbon atoms. １ represents a single bond, an ether group, or an ester group. ２ represents an alkylene group having 1 to 8 carbon atoms, a phenylene group, -(C ｎ H ２ｎ O) ｍ -(n represents 2 or 3, and m represents 2 or 3), or -CH ２ -CH(OH)-CH ２ - represents X ２ represents a single bond, an ether group, or an ester group. ３ represents a single bond, an alkylene group having 1 to 8 carbon atoms, or a group represented by the following formula (Y-1-1). *1 represents a bond bonded to X in formula (B). *2 represents a bond bonded to the benzene ring in formula (B). However, the total number of carbon atoms is 1 to 12. (In formula (Y-1-1), *3 represents a bond bonding to the benzene ring in formula (B). * represents a bond.) [5] The composition for forming a protective film according to any one of [1] to [4], wherein the compound (A) has, as a partial structure represented by formula (A-1), at least one of a structure represented by formula (A-1-1) below and a structure represented by formula (A-1-2) below: (In formula (A-1-1), Q １１ represents an alkylene group having 1 to 10 carbon atoms. * represents a bond. In formula (A-1-2), Q １２ represents a divalent organic group having 1 to 20 carbon atoms and having at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen in the main chain. * represents a bond.) [6] The composition for forming a protective film according to any one of [1] to [5], wherein the compound (A) has a structure represented by the following formula (A-2-1) as the partial structure represented by the formula (A-2): (In formula (A-2-1), X １１ represents a divalent group represented by the following formula (A-2-1-1), (A-2-1-2) or (A-2-1-3). １ and Z ２ each independently represents a single bond or a divalent group represented by the following formula (A-2-1-4): A each independently represents a hydrogen atom, a methyl group, or an ethyl group; * represents a bond. (In formulas (A-2-1-1) to (A-2-1-3), R １ ~R ５ R each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkenyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkynyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one monovalent group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms. １ and R ２may be bonded to each other to form a ring having 3 to 6 carbon atoms. ３ and R ４ may be bonded to each other to form a ring having 3 to 6 carbon atoms. * represents a bond. *1 represents a bond bonded to a carbon atom. *2 represents a bond bonded to a nitrogen atom. (In formula (A-2-1-4), m1 is an integer of 1 to 4, and m2 is 0 or 1. *3 represents a bond bonded to a nitrogen atom. *4 represents a bond bonded to a carbon atom.) [7] A protective film against a semiconductor wet etching solution, which is a fired product of a coating film made of the composition for forming a protective film according to any one of [1] to [6]. [8] A method for manufacturing a substrate with a protective film, comprising the steps of applying the composition for forming a protective film according to any one of [1] to [6] onto a semiconductor substrate having a step and firing the composition to form a protective film. [9] A method for manufacturing a substrate with a resist pattern, used in manufacturing a semiconductor, comprising the steps of applying the composition for forming a protective film according to any one of [1] to [6] onto a semiconductor substrate and firing the composition to form a protective film as a resist underlayer film, and forming a resist film on the protective film directly or via another layer, and then exposing and developing the composition to form a resist pattern.

[10] A method for manufacturing a semiconductor device, comprising the steps of forming a protective film on a semiconductor substrate having an inorganic film formed on its surface using the composition for forming a protective film according to any one of [1] to [6], forming a resist pattern on the protective film directly or via another layer, dry-etching the protective film using the resist pattern as a mask to expose the surface of the inorganic film, and wet-etching the inorganic film using a semiconductor wet etching solution using the protective film after dry etching as a mask.

[0008] According to the present invention, it is possible to provide a protective film-forming composition that can form a protective film that has excellent resistance to solvents contained in the resist composition, and that can form a protective film that has a high etching rate and excellent resistance to semiconductor wet etching solutions. Furthermore, according to the present invention, it is possible to provide a protective film formed from the protective film-forming composition, a method for manufacturing a resist-patterned substrate using the protective film, and a method for manufacturing a semiconductor device.

[0009] FIG. 1 is a schematic diagram for explaining a method for measuring damage in a resistance test to hydrogen peroxide solution in the examples.

[0010] (Composition for forming protective film) The composition for forming a protective film of the present invention is a composition for forming a protective film. The protective film is preferably a protective film that protects an inorganic film formed on a surface of a semiconductor substrate from wet etching. The composition for forming a protective film contains compound (A), compound (B), and a solvent.

[0011] By adding compound (B) to a protective film-forming composition containing compound (A), which can form a protective film that has excellent resistance to the solvent contained in the resist composition, the resulting protective film has a higher etching rate and is more resistant to a wet etching solution for semiconductors.

[0012] <Compound (A)> Compound (A) has a partial structure represented by the following formula (A-1) and a partial structure represented by the following formula (A-2). (In formula (A-1), X １ and X ２ each independently represents a single bond or a carbonyl group. １ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond. In formula (A-2), each A independently represents a hydrogen atom, a methyl group, or an ethyl group. Q ２ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond.

[0013] Q １ and Q ２ There are no particular limitations on the divalent organic group having 1 to 20 carbon atoms. １ and Q ２ Each of the divalent organic groups having 1 to 20 carbon atoms may or may not have a heteroatom. Examples of heteroatoms include an oxygen atom, a nitrogen atom, and a sulfur atom. １ may or may not have a ring structure. ２ may or may not have a ring structure.

[0014] <<Partial Structure Represented by Formula (A-1)>> From the viewpoint of suitably obtaining the effects of the present invention, compound (A) preferably has, as the partial structure represented by formula (A-1), at least one of a structure represented by formula (A-1-1) below and a structure represented by formula (A-1-2) below. (In formula (A-1-1), Q １１ represents an alkylene group having 1 to 10 carbon atoms. * represents a bond. In formula (A-1-2), Q １２ represents a divalent organic group having 1 to 20 carbon atoms and at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen in the main chain. * represents a bond.

[0015] Q in formula (A-1-1) １１ The alkylene group in the formula (I) is, for example, a non-cyclic alkylene group. Examples of such alkylene groups include linear alkylene groups and branched alkylene groups.

[0016] Q in formula (A-1-2) １２ Examples of the divalent organic group include linear, branched, or cyclic divalent organic groups having 2 to 20 carbon atoms and at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen. Among these, divalent organic groups having an oxygen atom or a sulfur atom are preferred.

[0017] Examples of the structure represented by formula (A-1-1) include the structures exemplified below. (* represents a bond.)

[0018] Examples of the structure represented by formula (A-1-2) include the structures exemplified below. (* represents a bond.)

[0019] The compound (A) may have a structure represented by the following formula (A-1-3) as a partial structure represented by formula (A-1). (In formula (A-1-3), R １１ represents an (n+2)-valent group having at least one of an aromatic hydrocarbon ring and an aliphatic hydrocarbon ring. １２represents a hydrogen atom, or an alkyl group having 1 to 13 carbon atoms which may be substituted with at least one group selected from the group consisting of an alkoxy group having 1 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylthio group having 1 to 13 carbon atoms, a nitro group, an alkylsulfonyloxy group having 1 to 13 carbon atoms, and an alkoxysulfonyl group having 1 to 13 carbon atoms. n represents 1 or 2. When n is 2, two R １２ may be the same or different. * represents a bond.)

[0020] The number of carbon atoms in the (n+2)-valent organic group is not particularly limited, but is preferably 4 to 30, more preferably 4 to 20, and particularly preferably 4 to 15. Examples of aromatic hydrocarbon rings contained in the (n+2)-valent organic group include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of aliphatic hydrocarbon rings include a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. The aliphatic hydrocarbon ring may have a polycyclic structure. The aliphatic hydrocarbon ring may or may not have an unsaturated bond. The aliphatic hydrocarbon ring may be an aliphatic hydrocarbon ring constituting a bridged polycyclic structure. The bridged polycyclic structure may have a heteroatom as an atom constituting the polycyclic structure. Examples of heteroatoms include an oxygen atom and a nitrogen atom. Examples of bridged polycyclic structures include a norbornene ring.

[0021] R in formula (A-1-3) １１ Examples of the trivalent organic group include the following: The following trivalent organic groups may be substituted with an alkyl group, an alkylcarbonyl group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, a halogen atom, a nitro group, or a combination of two or more thereof. In each of the following formulas, * represents a bond.

[0022] The trivalent organic group is preferably a trivalent organic group represented by the following formula: (wherein q represents an integer of 0 to 3, R ２ represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. However, when q represents 2 or 3, R ２ may be the same or different. * represents a bond.)

[0023] (In formulas (x-1) to (x-11), R １ ~R ４ R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and a fluorine atom, or a phenyl group. ５ and R ６ each independently represents a hydrogen atom or a methyl group. * represents a bond.

[0024] (In formulas (X3-1) and (X3-2), x and y each independently represent a single bond, an ether bond, a carbonyl group, an ester bond, an alkanediyl group having 1 to 5 carbon atoms, 1,4-phenylene, a sulfonyl bond, or an amide group. j and k are integers of 0 or 1. * represents a bond.) * represents a bond.

[0025] The tetravalent organic group represented by formula (X3-1) or (X3-2) may have a structure represented by any one of the following formulas (X3-3) to (X3-19). * represents a bond.

[0026] In formula (A-1-3), R １２ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 13 carbon atoms. The alkyl group having 1 to 13 carbon atoms may be substituted with at least one group selected from the group consisting of an alkoxy group having 1 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylthio group having 1 to 13 carbon atoms, a nitro group, an alkylsulfonyloxy group having 1 to 13 carbon atoms, and an alkoxysulfonyl group having 1 to 13 carbon atoms.

[0027] As the alkyl group having 1 to 13 carbon atoms, an alkyl group having 1 to 8 carbon atoms is preferred, and an alkyl group having 1 to 6 carbon atoms is more preferred. As the alkoxy group having 1 to 13 carbon atoms, an alkoxy group having 1 to 8 carbon atoms is preferred, and an alkoxy group having 1 to 6 carbon atoms is more preferred. As the alkylcarbonyloxy group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 8 carbon atoms is preferred, and an alkylcarbonyloxy group having 2 to 6 carbon atoms is more preferred. As the alkoxycarbonyl group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms is preferred, and an alkoxycarbonyl group having 2 to 6 carbon atoms is more preferred. As the alkylthio group having 1 to 13 carbon atoms, an alkylthio group having 1 to 8 carbon atoms is preferred, and an alkylthio group having 1 to 6 carbon atoms is more preferred. As the alkylsulfonyloxy group having 1 to 13 carbon atoms, an alkylsulfonyloxy group having 1 to 8 carbon atoms is preferred, and an alkylsulfonyloxy group having 1 to 6 carbon atoms is more preferred. As the alkoxysulfonyl group having 1 to 13 carbon atoms, an alkoxysulfonyl group having 1 to 8 carbon atoms is preferred, and an alkoxysulfonyl group having 1 to 6 carbon atoms is more preferred.

[0028] <<Partial Structure Represented by Formula (A-2)>> From the viewpoint of suitably obtaining the effects of the present invention, compound (A) preferably has a structure represented by the following formula (A-2-1) as the partial structure represented by formula (A-2): (In formula (A-2-1), X １１ represents a divalent group represented by the following formula (A-2-1-1), (A-2-1-2) or (A-2-1-3). １ and Z ２ each independently represents a single bond or a divalent group represented by the following formula (A-2-1-4): A each independently represents a hydrogen atom, a methyl group, or an ethyl group; * represents a bond. (In formulas (A-2-1-1) to (A-2-1-3), R １ ~R ５R each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkenyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkynyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one monovalent group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms. １ and R ２ may be bonded to each other to form a ring having 3 to 6 carbon atoms. ３ and R ４ may be bonded to each other to form a ring having 3 to 6 carbon atoms. * represents a bond. *1 represents a bond bonded to a carbon atom. *2 represents a bond bonded to a nitrogen atom. (In formula (A-2-1-4), m1 is an integer of 1 to 4, m2 is 0 or 1, *3 represents a bond bonded to a nitrogen atom, and *4 represents a bond bonded to a carbon atom.)

[0029] R in formulas (A-2-1-1) to (A-2-1-3) １ ~R ５ Examples of the alkyl group having 1 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom in the formula (I) include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, an alkoxyalkoxyalkyl group having 3 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, and an alkylthioalkyl group having 2 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom may contain two or more oxygen atoms or sulfur atoms.

[0030] <<<X １１ >>> X in formula (A-2-1) １１ From the viewpoint of suitably obtaining the effects of the present invention, it is preferable that the compound represented by formula (A-2-1-3) is used.

[0031] The structure represented by the following (1A) in formula (A-2-1) is (In formula (1A), Z １ , Z ２ and X １１ respectively represent Z in formula (A-2-1). １ , Z ２ and X １１ (The symbol * represents a bond.) For example, the following structures are given as examples.

[0032] In the above structure, * represents a bond.

[0033] The compound (A) may have a structure represented by the following formula (A-2-2) as the partial structure represented by formula (A-2). In formula (A-2-2), Q ２１ represents a divalent organic group having an aromatic hydrocarbon ring or an aliphatic hydrocarbon ring. Each A independently represents a hydrogen atom, a methyl group, or an ethyl group. Each n1 and n2 independently represents 0 or 1. * represents a bond.

[0034] <<<Q ２１ >>> Q in formula (A-2-2) ２１ is, for example, represented by any one of the following formulas (A-2-2-1) to (A-2-2-4). (In formulas (A-2-2-1) to (A-2-2-4), R ２１ ~R ２６ each independently represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an alkynyloxy group having 2 to 6 carbon atoms, an acyl group having 2 to 6 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an arylcarbonyl group having 7 to 13 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. * represents a bond. In formula (A-2-2-1), n3 represents 0 or 1. When n3 is 0, n11 represents an integer of 0 to 4. When n3 is 1, n11 represents an integer of 0 to 6. R２１ When is 2 or more, R is 2 or more ２１ In formula (A-2-2-2), Z may be the same or different. １ represents a single bond, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group having 1 to 6 carbon atoms. n12 and n13 each independently represent an integer of 0 to 4. R ２２ When is 2 or more, R is 2 or more ２２ may be the same or different. ２３ When is 2 or more, R is 2 or more ２３ In formula (A-2-2-3), Y may be the same or different. １ and Y ２ each independently represents a single bond or an alkylene group having 1 to 6 carbon atoms. n14 represents an integer of 0 to 4. R ２４ When is 2 or more, R is 2 or more ２４ In formula (A-2-2-4), Z may be the same or different. ２ represents a single bond, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group having 1 to 6 carbon atoms. n15 and n16 each independently represent an integer of 0 to 4. R ２５ When is 2 or more, R is 2 or more ２５ may be the same or different. ２６ When is 2 or more, R is 2 or more ２６ may be the same or different.)

[0035] As used herein, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. As used herein, alkyl groups are not limited to linear ones, and may be branched or cyclic. Examples of linear or branched alkyl groups include methyl groups, ethyl groups, isopropyl groups, tert-butyl groups, and n-hexyl groups. Examples of cyclic alkyl groups (cycloalkyl groups) include cyclobutyl groups, cyclopentyl groups, and cyclohexyl groups. As used herein, examples of alkoxy groups include methoxy groups, ethoxy groups, n-pentyloxy groups, and isopropoxy groups. As used herein, examples of alkylthio groups include methylthio groups, ethylthio groups, n-pentylthio groups, and isopropylthio groups. As used herein, examples of alkenyl groups include ethenyl, 1-propenyl, 2-propenyl, 1-methyl-1-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, and 2-methyl-2-propenyl groups. As used herein, examples of alkynyl groups include groups in which the double bond of the alkenyl groups listed above for "alkenyl groups" is replaced with a triple bond. As used herein, examples of alkenyloxy groups include vinyloxy, 1-propenyloxy, 2-n-propenyloxy (allyloxy), 1-n-butenyloxy, and prenyloxy groups. As used herein, examples of alkynyloxy groups include 2-propynyloxy, 1-methyl-2-propynyloxy, 2-methyl-2-propynyloxy, 2-butynyloxy, and 3-butynyloxy groups. As used herein, examples of acyl groups include acetyl groups and propionyl groups. As used herein, examples of aryloxy groups include phenoxy groups and naphthyloxy groups. As used herein, examples of arylcarbonyl groups include phenylcarbonyl groups. As used herein, examples of aralkyl groups include benzyl groups and phenethyl groups.In this specification, examples of the alkylene group include a methylene group, an ethylene group, a 1,3-propylene group, a 2,2-propylene group, a 1-methylethylene group, a 1,4-butylene group, a 1-ethylethylene group, a 1-methylpropylene group, a 2-methylpropylene group, a 1,5-pentylene group, a 1-methylbutylene group, a 2-methylbutylene group, a 1,1-dimethylpropylene group, a 1,2-dimethylpropylene group, a 1-ethylpropylene group, a 2-ethylpropylene group, a 1,6-hexylene group, a 1,4-cyclohexylene group, a 1,8-octylene group, a 2-ethyloctylene group, a 1,9-nonylene group, and a 1,10-decylene group.

[0036] The structure represented by the following (2A) in formula (A-2-2) is: (In formula (2A), Q ２１ , n1 and n2 are respectively Q in formula (A-2-2) ２１ , n1 and n2 are the same. * represents a bond.) For example, the following structures can be mentioned. In the above structure, * represents a bond.

[0037] From the viewpoint of suitably achieving the effects of the present invention, compound (A) preferably has the following partial structure. For example, when compound (A) has a partial structure represented by formula (A-1-1), it preferably has a partial structure represented by formula (A) below as a structure containing the partial structure represented by formula (A-1-1). Alternatively, for example, when compound (A) has a partial structure represented by formula (A-1-2), it preferably has a partial structure represented by formula (B) below as a structure containing the partial structure represented by formula (A-1-2). (In formulas (A) and (B), X １１ , Z １ , Z ２ and A are X in formula (A-2-1), respectively. １１ , Z １ , Z ２ and A. In formula (A), Q １１ is Q in formula (A-1-1) １１ In formula (B), Q １２is Q in formula (A-1-2) １２ is the same as

[0038] <<Method for Producing Compound (A)>> The method for producing compound (A) is not particularly limited, and examples thereof include a method of reacting a compound represented by the following formula (A1) with an epoxy compound represented by the following formula (A2).

[0039] Examples of catalysts that activate epoxy groups include quaternary phosphonium salts such as tetrabutylphosphonium bromide and ethyltriphenylphosphonium bromide, and quaternary ammonium salts such as benzyltriethylammonium chloride. The amount of catalyst used can be selected appropriately from the range of 0.1 to 10% by mass based on the total mass of the raw compound materials used in the reaction. Optimal conditions for the temperature and time of the polymerization reaction can be selected, for example, from the ranges of 80 to 160°C and 2 to 50 hours.

[0040] (In formula (A1), X １ , X ２ and Q １ respectively represent X in formula (A-1). １ , X ２ and Q １ In formula (A2), Q ２ and A are Q in formula (A-2), respectively. ２ and A are the same.)

[0041] When producing compound (A), the compound represented by formula (A1) can be used alone or in combination of two or more. When producing compound (A), the epoxy compound represented by formula (A2) can be used alone or in combination of two or more.

[0042] When compound (A) has a structure represented by formula (A-1-3) as a partial structure represented by formula (A-1), the structure represented by formula (A-1-3) is derived from, for example, a tetracarboxylic dianhydride represented by the following formula (A3) or a tricarboxylic anhydride represented by the following formula (A3): (In formula (A3) and formula (A4), R １１represents R in formula (A-1-3). １１ is synonymous with

[0043] In addition, R in the structure represented by formula (A-1-3) １２ is derived from a compound represented by the following formula (C), for example: The compound represented by formula (C) may also serve as a solvent in the reaction system when producing compound (A). (In formula (C), R １２ represents R in formula (A-1-3). １２ is synonymous with

[0044] The weight-average molecular weight Mw of compound (A) is not particularly limited, but the lower limit is preferably, for example, 900 or more, more preferably 950 or more, and even more preferably 1,000 or more. The upper limit of the weight-average molecular weight Mw is also not particularly limited, but the weight-average molecular weight Mw is preferably 50,000 or less. Compound (A) is more preferably a polymer having a weight-average molecular weight Mw of 900 to 50,000, even more preferably a weight-average molecular weight Mw of 950 to 30,000, and particularly preferably a weight-average molecular weight Mw of 1,000 to 10,000. In the present invention, the weight-average molecular weight Mw is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0045] The content of compound (A) in the composition for forming a protective film is not particularly limited, but is preferably 50% by mass to 99% by mass, more preferably 70% by mass to 97% by mass, and particularly preferably 85% by mass to 95% by mass, based on the non-volatile content. The non-volatile content refers to components other than the solvent in the composition for forming a protective film.

[0046] <Compound Represented by Formula (B)> The composition for forming a protective film contains a compound (B) represented by the following formula (B). (In formula (B), n represents an integer of 2 to 10. When n is 2, X represents a sulfinyl group, a sulfonyl group, an ether group, or a divalent organic group having 2 to 50 carbon atoms. When n is an integer other than 2, X represents an n-valent organic group having 2 to 50 carbon atoms. Y represents a single bond or a divalent linking group having 1 to 12 carbon atoms.)

[0047] <<n>> n represents an integer of 2 to 10, preferably an integer of 2 to 6, even more preferably an integer of 2 to 4, and particularly preferably 2 or 3.

[0048] <<X>> When n is 2, X represents a sulfinyl group, a sulfonyl group, an ether group, or a divalent (n-valent) organic group having 2 to 50 carbon atoms. When n is an integer other than 2, X represents an n-valent organic group having 2 to 50 carbon atoms.

[0049] The n-valent organic group having 2 to 50 carbon atoms may be, for example, an n-valent organic group having 3 to 10 carbon atoms. Here, n-valency includes divalency. The n-valent organic group having 2 to 50 carbon atoms has, for example, a ring structure. Examples of ring structures include aromatic hydrocarbon rings, heterocyclic rings, and aliphatic rings. The n-valent organic group having 2 to 50 carbon atoms preferably has at least one of an aromatic hydrocarbon ring and a heterocyclic ring. Examples of aromatic hydrocarbon rings include benzene, naphthalene, anthracene, acenaphthene, fluorene, triphenylene, phenalene, phenanthrene, indene, indane, indacene, pyrene, chrysene, perylene, naphthacene, pentacene, coronene, heptacene, benzo[a]anthracene, dibenzophenanthrene, and dibenzo[a,j]anthracene. Examples of heterocyclic rings include furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, pyrrolidine, piperidine, piperazine, morpholine, quinuclidine, indole, purine, thymine, quinoline, isoquinoline, chromene, thianthrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, hydantoin, uracil, barbituric acid, triazine, and cyanuric acid. The heterocyclic ring may be a triazinetrione. The ring structure may have a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms, which may be interrupted by an oxygen atom or a sulfur atom, an alkenyl group having 1 to 10 carbon atoms, which may be interrupted by an oxygen atom or a sulfur atom, or an alkynyl group having 1 to 10 carbon atoms, which may be interrupted by an oxygen atom or a sulfur atom. The alkyl group, alkenyl group, and alkynyl group may be linear or branched. The term "optionally interrupted" means that any carbon-carbon bond in the alkyl group, alkenyl group, or alkynyl 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).

[0050] When n is 2, the n-valent organic group having 2 to 50 carbon atoms may be, for example, an alkylene group having 2 to 6 carbon atoms.

[0051] The n-valent organic group having 2 to 50 carbon atoms may contain a linear, branched, or cyclic saturated or unsaturated hydrocarbon group, an aromatic group, a heteroaromatic group, an ether group, a hydroxyl group, an ester group, a keto group, an amino group, a halogen group, a sulfide group, a carboxyl group, a sulfo group, an amido group, an imido group, a cyano group, an aldehyde group, an imino group, a urea group, a carbamate group, a carbonate group, a nitro group, or a sulfone group.

[0052] X is preferably a divalent to pentavalent heterocyclic group having 3 to 10 carbon atoms.

[0053] Examples of X include the following groups. (* represents a bond.)

[0054] <<Y>> Y represents a single bond or a divalent linking group having 1 to 12 carbon atoms. Examples of the divalent linking group having 1 to 12 carbon atoms include divalent linking groups having 1 to 12 carbon atoms represented by the following formula (Y-1): (In formula (Y-1), R １ represents a single bond or an alkylene group having 1 to 4 carbon atoms. １ represents a single bond, an ether group, or an ester group. ２ represents an alkylene group having 1 to 8 carbon atoms, a phenylene group, -(C ｎ H ２ｎ O) ｍ -(n represents 2 or 3, and m represents 2 or 3), or -CH ２ -CH(OH)-CH ２ - represents X ２ represents a single bond, an ether group, or an ester group. ３ represents a single bond, an alkylene group having 1 to 8 carbon atoms, or a group represented by the following formula (Y-1-1). *1 represents a bond bonded to X in formula (B). *2 represents a bond bonded to the benzene ring in formula (B). However, the total number of carbon atoms is 1 to 12. (In formula (Y-1-1), *3 represents a bond bonding to the benzene ring in formula (B). * represents a bond.)

[0055] Examples of the divalent linking group represented by formula (Y-1) include the following divalent linking groups: (*1) an alkylene group having 1 to 10 carbon atoms (*2) (*1) a phenylene group (*2) (*1) -C(=O)O- (*2) (*1) -OC(=O)O- (*2) (*1) -CH ２ OC(=O)-(*2) ・(*1)-CH ２ CH ２ OC(=O)-(*2) ・(*1)-CH ２ CH ２ CH ２ OC(=O)-(*2) ・(*1)-CH(CH ３ )OC(=O)-(*2) ・(*1)-CH ２ CH ２ CH ２ CH ２ OC(=O)-(*2) ・(*1)-CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ OC(=O)-(*2) ・(*1)-OCH ２ CH ２ OC(=O)-(*2) ・(*1)-OCH ２ CH ２ OCH ２ CH ２ OC(=O)-(*2) ・(*1)-OCH ２ CH ２ OCH ２ CH ２ OCH ２ CH ２ OC(=O)-(*2) ・(*1)-OCH ２ CH(OH)CH ２ O-(*2) ・(*1)-OCH ２ CH(OH)CH ２ OC(=O)-(*2) ・(*1)-CH ２ CH(OH)CH ２ OC(=O)-(*2) ・(*1)-CH ２ CH(OH)CH ２ OC(=O)-(*2) ・(*1)-CH２ -CH(OH)-CH ２ -OC(=O)-CH ２ CH ２ -(*2) ・(*1)-CH ２ -CH(OH)-CH ２ -OC(=O)-C(CN)=CH-(*2) ・(*1)-O-CH ２ -CH(OH)-CH ２ -OC(=O)-C(CN)=CH-(*2) ・(*1)-C(=O)O-CH ２ -CH(OH)-CH ２ —OC(═O)—C(CN)═CH—(*2) (*1 and *2 have the same meanings as *1 and *2 in formula (Y-1), respectively.)

[0056] Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group, an isopropylidene group, an ethylidene group, a carbonyl group, a tetramethylene group, a cyclohexanediyl group, and a decanediyl group.

[0057] Examples of the compound (B) represented by formula (B) include the following compounds.

[0058] A synthesis example of the compound (B) represented by formula (B) is shown below.

[0059] The molecular weight of compound (B) is not particularly limited, but is preferably a weight average molecular weight of 236 to 3000, more preferably 250 to 2500, and particularly preferably 300 to 2000. When n is 2, X is an ether group, and Y is a single bond in formula (B), the molecular weight of the compound represented by formula (B) is 236.

[0060] The content of compound (B) in the composition for forming a protective film is not particularly limited, but is preferably 1% by mass to 50% by mass, more preferably 2% by mass to 35% by mass, and particularly preferably 3% by mass to 20% by mass, relative to compound (A).

[0061] <Solvent> The solvent used in the protective film-forming composition is not particularly limited as long as it can uniformly dissolve the solid components contained therein at room temperature, but organic solvents generally used in chemical solutions for semiconductor lithography processes are preferred. Specifically, 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, cyclohexanone, cyclohexane, cyclohexane-1, cyclohexane-2, cyclohexane-3, cyclohexane-4, cyclohexane-5, cyclohexane-6, cyclohexane-7, cyclohexane-8, cyclohexane-9, cyclohexane-10, cyclohexane-11, cyclohexane-12, cyclohexane-13, cyclohexane-14, cyclohexane-15, cyclohexane-16, cyclohexane-17, cyclohexane-18, cyclohexane-19, cyclohexane-20, cyclohexane-21, cyclohexane-22, cyclohexane-23, cyclohexane-24, cyclohexane-25, cyclohexane-26, cyclohexane-27, cyclohexane-28, cyclohexane-29, cyclohexane-30, cyclohexane-31, cyclohexane-32, cyclohexane-33, cyclohexane-34, cyclohexane-35, cyclohexane-36, cyclohexane-37, cyclohexane-38, cyclohexane-49, cyclohexane-49, cyclohexane-49, cyclohexane-49, cyclohexane-51, cyclohexane-52, cyclohexane-19, cyclohexane-19, cyclohexane-29, cyclohexane-19, cyclohexane Examples of suitable solvents include heptanone, 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 may be used alone or in combination of two or more.

[0062] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred, with propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate being particularly preferred.

[0063] <Curing Catalyst> The curing catalyst (crosslinking catalyst) contained as an optional component in the protective film-forming composition may be either a thermal acid generator or a photoacid generator, but it is preferable to use a thermal acid generator.

[0064] Examples of the thermal acid generator include sulfonic acid compounds and carboxylic acid compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate (pyridinium p-toluenesulfonic acid), pyridinium phenolsulfonic acid, pyridinium p-hydroxybenzenesulfonic acid (pyridinium p-phenolsulfonate salt), pyridinium trifluoromethanesulfonic acid, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

[0065] Examples of the photoacid generator include an onium salt compound, a sulfonimide compound, and a disulfonyldiazomethane compound.

[0066] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0067] Examples of sulfonimide compounds include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0068] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0069] The curing catalyst may be used alone or in combination of two or more.

[0070] When a curing catalyst is used, the content of the curing catalyst is, for example, 0.1% by mass to 20% by mass, and preferably 1% by mass to 10% by mass, relative to the compound (A).

[0071] <Crosslinking Agent> The protective film-forming composition may further contain the crosslinking agent described below as an optional component. Examples of crosslinking agents include melamine-based crosslinkers having an alkoxymethyl group, substituted urea-based crosslinkers, and compounds thereof. Examples of the alkoxy group include alkoxy groups having 1 to 10 carbon atoms, such as methoxy, ethoxy, propoxy, and butoxy. Examples of methyl groups having such alkoxy groups include methoxymethyl, ethoxymethyl, propoxymethyl, and butoxymethyl groups. Preferred are cross-linking agents having at least two bridge-forming substituents, such as hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine, 1,3,4,6-tetrakis(methoxymethyl)glycoluril (tetramethoxymethylglycoluril) (POWDERLINK® 1174), 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, and 1,1,3,3-tetrakis(methoxymethyl)urea.

[0072] Furthermore, a crosslinking agent having high heat resistance can be used as the crosslinking agent, such as a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule.

[0073] This compound may be a compound having a partial structure of the following formula (H-1), or a polymer or oligomer having a repeating unit of the following formula (H-2).

[0074] 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.

[0075] m1 is 1≦m1≦(6-m2). m2 is 1≦m2≦5. m3 is 1≦m3≦(4-m2). m4 is 1≦m4≦3.

[0076] Examples of the compounds, polymers and oligomers of formula (H-1) and formula (H-2) are shown below.

[0077] (In the formula, Me represents a methyl group.)

[0078] (In the formula, Me represents a methyl group.)

[0079] 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 (H-1-23) is available from Honshu Chemical Industry Co., Ltd. under the trade name TMOM-BP. The compound of formula (H-1-20) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TM-BIP-A.

[0080] The crosslinking agent may also be a nitrogen-containing compound having 2 to 6 substituents bonded to nitrogen atoms and represented by the following formula (1d) per molecule, as described in WO 2017 / 187969:

[0081] (In formula (1d), R １ represents a methyl group or an ethyl group. * represents a bond to the nitrogen atom.)

[0082] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (1d) in one molecule may be a glycoluril derivative represented by the following formula (1E).

[0083] (In formula (1E), four R １ each independently represents a methyl group or an ethyl group, R ２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.

[0084] Examples of the glycoluril derivative represented by the formula (1E) include compounds represented by the following formulas (1E-1) to (1E-6).

[0085]

[0086] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (1d) in one molecule can be obtained by reacting a nitrogen-containing compound having 2 to 6 substituents bonded to a nitrogen atom in one molecule, represented by the following formula (2d), with at least one compound represented by the following formula (3d):

[0087] (In formula (2d) and formula (3d), R １ represents a methyl group or an ethyl group, R ４ represents an alkyl group having 1 to 4 carbon atoms. * represents a bond to a nitrogen atom.)

[0088] The glycoluril derivative represented by the formula (1E) can be obtained by reacting a glycoluril derivative represented by the following formula (2E) with at least one compound represented by the formula (3d).

[0089] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (2d) in one molecule is, for example, a glycoluril derivative represented by the following formula (2E).

[0090] (In formula (2E), R ２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group; R ４ each independently represents an alkyl group having 1 to 4 carbon atoms.

[0091] Examples of glycoluril derivatives represented by formula (2E) include compounds represented by formulas (2E-1) to (2E-4) below. Furthermore, examples of compounds represented by formula (3d) include compounds represented by formulas (3d-1) and (3d-2) below.

[0092]

[0093] The entire disclosure of WO 2017 / 187969 is incorporated herein by reference with respect to the content of a nitrogen-containing compound having 2 to 6 substituents bonded to a nitrogen atom and represented by formula (1d) per molecule.

[0094] When a crosslinking agent is used, the content of the crosslinking agent relative to the compound (A) is, for example, 1% by mass to 50% by mass, and preferably 5% by mass to 30% by mass.

[0095] <Other Components> A surfactant may be further added to the protective film-forming composition to prevent pinholes, striations, etc., and further improve application properties for surface unevenness. Examples of surfactants 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 octylphenol ether and polyoxyethylene nonylphenol 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; and polyoxyethylene sorbitan monopalmitate. nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorine-based surfactants such as Eftop EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, R-30, and R-40 (trade names, manufactured by DIC Corporation), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of these surfactants to be added is usually 2.0% by mass or less, and preferably 1.0% by mass or less, based on the total solid content of the protective film-forming composition. These surfactants may be added alone or in combination of two or more.

[0096] The nonvolatile content of the composition for forming a protective film, that is, the content of components excluding the solvent, is, for example, 0.01% by mass to 10% by mass.

[0097] (Protective film, method for manufacturing a substrate with a protective film, method for manufacturing a substrate with a resist pattern, and method for manufacturing a semiconductor device) The protective film of the present invention is a fired product of a coating film made of a composition for forming a protective film. The method for manufacturing a substrate with a protective film of the present invention includes a step of applying the composition for forming a protective film of the present invention to a semiconductor substrate having a step and firing the composition to form a protective film.

[0098] The method for producing a substrate having a resist pattern of the present invention includes the following steps (1) and (2): Step (1): A step of applying the composition for forming a protective film of the present invention onto a semiconductor substrate and baking the composition to form a protective film as a resist underlayer film; Step (2): A step of forming a resist film on the protective film directly or via another layer, followed by exposure and development to form a resist pattern.

[0099] The method for manufacturing a semiconductor device of the present invention includes the following steps (A) to (D): step (A): forming a protective film on a semiconductor substrate having an inorganic film formed on its surface using the protective film-forming composition of the present invention; step (B): forming a resist pattern on the protective film directly or via another layer; step (C): dry-etching the protective film using the resist pattern as a mask to expose the surface of the inorganic film; step (D): wet-etching the inorganic film using a semiconductor wet etching solution using the protective film after dry etching as a mask.

[0100] Examples of semiconductor substrates onto 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.

[0101] 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 films, silicon oxide films, silicon nitride films, silicon oxynitride films, borophosphosilicate glass (BPSG) films, titanium nitride films, titanium oxynitride films, tungsten nitride films, gallium nitride films, and gallium arsenide films. The semiconductor substrate may be a stepped substrate having vias (holes), trenches (grooves), or the like formed therein. For example, the via has a substantially circular shape when viewed from above, with a diameter of, for example, 2 nm to 20 nm and a depth of, for example, 50 nm to 500 nm, and the trench has a groove (recess in the substrate) with a width of, for example, 2 nm to 20 nm and a depth of, for example, 50 nm to 500 nm. The composition for forming a protective film of the present invention has a small weight-average molecular weight and average particle size of the compounds contained in the composition, and therefore, the composition can be used to fill uneven substrates such as those described above without defects such as voids (gaps), etc. The absence of defects such as voids is an important characteristic for the subsequent steps in semiconductor manufacturing (wet etching / dry etching of the semiconductor substrate, and resist pattern formation).

[0102] 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, the baking time is 0.5 to 30 minutes, and 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.

[0103] A resist film is formed on the protective film formed as described above, either directly or via another layer, followed by exposure and development to form a resist pattern. Exposure is performed through a mask (reticle) for forming a predetermined pattern, and 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 seconds to 300 seconds. Examples of alkaline developers that can be used 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, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant can be added to the aqueous alkali solution. Among these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants can be added to these developers. A method can also be used in which development is carried out with an organic solvent such as butyl acetate instead of an alkaline developer, and the parts of the photoresist where the alkaline dissolution rate is not improved are developed.

[0104] 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.

[0105] Furthermore, the protective film after dry etching (and the resist pattern, if any, remaining on the protective film) is used as a mask to perform wet etching using a semiconductor wet etching solution, thereby forming a desired pattern.

[0106] 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.

[0107] 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.

[0108] 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 solution obtained by mixing urea with hydrogen peroxide solution and heating to cause thermal decomposition of the urea to generate ammonia, which ultimately makes the pH basic, can also be used as a wet etching chemical.

[0109] Among these, acidic hydrogen peroxide solution or basic hydrogen peroxide solution is preferred.

[0110] These chemical solutions may contain additives such as surfactants.

[0111] 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.

[0112] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0113] The apparatus used to measure the weight-average molecular weight of the polymers obtained in the following synthesis examples is as follows: Apparatus: Tosoh Corporation HLC-8420GPC GPC column: Shodex (registered trademark) Asahipak (registered trademark) (Showa Denko K.K.) Column temperature: 40°C Flow rate: 0.35 mL / min Eluent: tetrahydrofuran (THF) Standard sample: polystyrene (Tosoh Corporation)

[0114] Synthesis Example 1 15.00 g of monomethyldiglycidyl isocyanuric acid (manufactured by Shikoku Chemicals Corporation, product name: Me-DGIC, 30 wt % propylene glycol monomethyl ether solution), 0.70 g of 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 4.32 g of 3,3-dithiopropionic acid, 0.45 g of tetrabutylphosphonium bromide, and 29.33 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred for 24 hours at an internal temperature of 100° C. under a nitrogen atmosphere. The resulting reaction product corresponded to formula (1-1), and had a weight average molecular weight Mw of 1883 as measured by GPC in terms of polystyrene.

[0115] Formula (1-1)

[0116] Synthesis Example 2 15.00 g of monomethyldiglycidyl isocyanuric acid (manufactured by Shikoku Chemicals Corporation, product name: Me-DGIC, 30 wt% propylene glycol monomethyl ether solution), 0.57 g of terephthalic acid diglycidyl ester (manufactured by Nagase ChemteX Corporation, product name: Denacol EX-711), 16.68 g of 2,2-thioglycolic acid (20 wt% propylene glycol monomethyl ether solution), 0.51 g of tetrabutylphosphonium bromide, and 11.43 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred for 24 hours at an internal temperature of 105°C under a nitrogen atmosphere. The resulting reaction product corresponded to formula (1-2), and had a weight average molecular weight Mw of 2161 as measured by GPC in terms of polystyrene.

[0117] Formula (1-2)

[0118] Synthesis Example 3 80.00 g of monomethyldiglycidyl isocyanuric acid (manufactured by Shikoku Chemicals Corporation, product name: Me-DGIC, 30 wt% propylene glycol monomethyl ether solution), 14.55 g of 2,2-thioglycolic acid (20 wt% propylene glycol monomethyl ether solution), 13.16 g of succinic acid, 2.42 g of tetrabutylphosphonium bromide, and 101.75 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred for 24 hours at an internal temperature of 100°C under a nitrogen atmosphere. The resulting reaction product corresponded to formula (1-3), and had a weight average molecular weight Mw of 1112 as measured by GPC in terms of polystyrene.

[0119] Formula (1-3)

[0120] Synthesis Example 4 A polymer having the same composition as the reaction product synthesized in Synthesis Example 3 of WO2018 / 203540 was synthesized. The synthesis method is described below. 2.29 g of monoallyl diglycidyl isocyanurate (manufactured by Shikoku Chemicals Corporation, product name: MA-DGIC), 1.50 g of HP-4032D (manufactured by DIC Corporation), 3.15 g of 3,3-dithiopropionic acid, 0.34 g of tetrabutylphosphonium bromide, and 29.21 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred for 20 hours at an internal temperature of 105°C under a nitrogen atmosphere. The resulting reaction product corresponded to formula (1-4), and had a weight average molecular weight Mw of 4500 as measured by GPC in terms of polystyrene.

[0121] Formula (1-4)

[0122] Synthesis Example 5 5.00 g of triazinetrione epoxy resin (product name: TEPIC, manufactured by Nissan Chemical Industries, Ltd.), 9.29 g of 3,4-dihydroxyhydrocinnamic acid, 0.64 g of tetrabutylphosphonium bromide, and 34.83 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred for 24 hours at an internal temperature of 80° C. under a nitrogen atmosphere. The resulting reaction product corresponded to formula (1-5), and had a weight average molecular weight Mw of 975 as measured by GPC in terms of polystyrene.

[0123] Formula (1-5)

[0124] Synthesis Example 6 20.00 g of monomethyldiglycidyl isocyanuric acid (manufactured by Shikoku Chemicals Corporation, product name: Me-DGIC, 30 wt % propylene glycol monomethyl ether solution), 8.90 g of 3,4-dihydroxyhydrocinnamic acid, 0.61 g of tetrabutylphosphonium bromide, and 22.11 g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred under a nitrogen atmosphere at an internal temperature of 80° C. for 24 hours. The resulting reaction product corresponded to formula (1-6), and had a weight average molecular weight Mw of 633 as measured by GPC in terms of polystyrene.

[0125] Formula (1-6)

[0126] Example 1 To 3.924 g of the solution (solid content 18.1 wt %) of the reaction product obtained in Synthesis Example 1 and corresponding to the formula (1-1), 0.145 g of the solution (solid content 24.5 wt %) of the reaction product obtained in Synthesis Example 5 and corresponding to the formula (1-5) as an additive, 0.036 g of pyridinium trifluoromethanesulfonate as a crosslinking catalyst, and 8.896 g of propylene glycol monomethyl ether were added to prepare a composition for forming a protective film.

[0127] Example 2 To 4.621 g of the solution (solid content 17.9 wt %) of the reaction product obtained in Synthesis Example 2 and corresponding to the formula (1-2), 0.169 g of the solution (solid content 24.5 wt %) of the reaction product obtained in Synthesis Example 5 and corresponding to the formula (1-5) as an additive, 0.031 g of pyridinium trifluoromethanesulfonate as a crosslinking catalyst, and 10.179 g of propylene glycol monomethyl ether were added to prepare a composition for forming a protective film.

[0128] Example 3 To 9.735 g of the solution (solid content 16.8 wt %) of the reaction product obtained in Synthesis Example 3 and corresponding to the formula (1-3), 0.334 g of the solution (solid content 24.5 wt %) of the reaction product obtained in Synthesis Example 5 and corresponding to the formula (1-5) as an additive, 0.082 g of pyridinium trifluoromethanesulfonate as a crosslinking catalyst, and 19.850 g of propylene glycol monomethyl ether were added to prepare a composition for forming a protective film.

[0129] Example 4 To 4.125 g of the solution (solid content 16.8 wt %) of the reaction product obtained in Synthesis Example 3 and corresponding to the formula (1-3), 0.208 g of the solution (solid content 25.0 wt %) of the reaction product obtained in Synthesis Example 6 and corresponding to the formula (1-6) as an additive, 0.035 g of pyridinium trifluoromethanesulfonate as a crosslinking catalyst, and 8.633 g of propylene glycol monomethyl ether were added to prepare a composition for forming a protective film.

[0130] Comparative Example 1 To 3.333 g of a solution (solid content 30.0 wt %) of an acrylic resin of a chemical solution-resistant protective film-forming composition represented by the following formula (1-7), 0.204 g of a solution (solid content 24.5 wt %) of the reaction product corresponding to the formula (1-5) obtained in Synthesis Example 5, 4.031 g of propylene glycol monomethyl ether, and 7.432 g of propylene glycol monomethyl ether acetate were added as additives, to prepare a protective film-forming composition.

[0131] Formula (1-7)

[0132] Comparative Example 2 To 4.807 g of a solution (solid content 17.2 wt %) of the reaction product corresponding to the formula (1-4) was added 0.031 g of pyridinium trifluoromethanesulfonate as a crosslinking catalyst, 0.041 g of gallic acid as an additive, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac R-40), and 10.120 g of propylene glycol monomethyl ether, to prepare a composition for forming a protective film.

[0133] [Resist Solvent Resistance Test] Each of the protective film-forming compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 was applied (spin coated) onto a silicon wafer using a spin coater. The coated silicon wafer was heated on a hot plate at 220°C for 1 minute to form a 150 nm-thick protective film. 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. After spin drying, the wafer was 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 (product name: Nanospec 6100, manufactured by Nanometrics Japan Co., Ltd.). Resist solvent resistance was evaluated by calculating the percentage of film thickness reduction (%) of the protective film removed by solvent immersion using the following formula. The results are shown in Table 1. It can be said that a film thickness reduction rate of about 1% or less has sufficient resist solvent resistance. Film thickness reduction rate (%) = ((A - B) / A) x 100 A: film thickness before immersion in solvent B: film thickness after immersion in solvent

[0134]

[0135] From the above results, the change in film thickness before and after immersion in the resist solvent was very small for the protective film-forming compositions of Examples 1 to 4 and Comparative Examples 1 and 2. Therefore, the protective film-forming compositions of Examples 1 to 4 have sufficient resist solvent resistance to function as a protective film.

[0136] [Evaluation of Etching Selectivity] Each of the protective film-forming compositions prepared in Examples 1 to 3 and Comparative Example 1 was applied to a silicon wafer using a spin coater to a film thickness of about 150 nm, and baked on a hot plate at 220°C for 60 seconds. The obtained protective film was subjected to CF etching using a dry etching apparatus (product name: RIE-200NL, manufactured by Samco Corporation). ４Dry etching was performed using a gas to measure the dry etching rate of the protective film and evaluate the etching selectivity. The measurement results of the etching selectivity are shown in Table 2. It can be said that the higher the etching selectivity, the faster the dry etching rate.

[0137]

[0138] From the above results, it can be said that the protective film-forming compositions of Examples 1 to 3 have a higher dry etching rate than the protective film-forming composition of Comparative Example 1. In other words, it is possible to shorten the etching time during dry etching of the protective film-forming composition, and to suppress the undesirable phenomenon of the film thickness of an upper layer film such as a resist being reduced when the protective film-forming composition is removed by dry etching. Furthermore, the ability to shorten the dry etching time reduces undesirable etching damage to the substrate underlying the protective film, making them particularly useful as protective film-forming compositions.

[0139] [Hydrogen Peroxide Resistance Test] Each of the protective film-forming compositions prepared in Examples 3 and 4 and Comparative Example 2 was applied to a TiN-deposited substrate (TiN thickness: 50 nm) using a spin coater, and heated at 220°C for 1 minute to form a protective film with a thickness of 150 nm. Next, an i-line resist (manufactured by Tokyo Ohka Kogyo Co., Ltd., product name: THMR-iP1800EP) was applied to a thickness of approximately 1.2 μm using a spin coater, and prebaked on a hot plate at 90°C for 90 seconds to form a photoresist laminate. Next, using a stepper (manufactured by Nikon Corporation, NSR-2205i12D), the photoresist laminate was subjected to i-line exposure through a pattern mask for resolution measurement. After exposure, the resist was post-baked at 110°C for 90 seconds and developed with a resist developer, a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) (product name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.), to obtain a 1.0 µm 1:1 line and space resist pattern. Next, the TiN deposition substrate with the resist pattern was subjected to a dry etching process using a dry etching apparatus (product name: RIE-200NL, manufactured by Samco Co., Ltd.) to remove N ２ / O２ Dry etching with gas was performed using the resist pattern as a mask to remove the protective film and TiN layer from areas where the resist pattern was not attached (space areas), and the resist pattern (line-and-space pattern) was transferred to the protective film and TiN layer. The resulting TiN-deposited substrate was then immersed in 14 wt % hydrogen peroxide solution heated to 60°C for 525 seconds, and the cross-sectional shape of the TiN layer in the line area was observed using a scanning electron microscope. The length of the TiN layer dissolved by the hydrogen peroxide solution was measured and evaluated as damage. A schematic diagram illustrating the measurement method is shown in Figure 1. The length of the TiN layer dissolved by the hydrogen peroxide solution refers to the length L of the line where the observed cross section intersects with the surface of the TiN layer 2 that is in contact with the protective film 3 under the resist film 4 and that was dissolved by the hydrogen peroxide solution. In this measurement method, dissolution of the TiN layer 2 by hydrogen peroxide solution occurs when hydrogen peroxide solution penetrates into the interface between the protective film 3 and the TiN layer 2 from the side of the TiN layer 2. Therefore, resistance to hydrogen peroxide solution was evaluated by measuring this length L. The results of the hydrogen peroxide solution resistance test are shown in Table 3. The damage to the TiN layer in Comparative Example 2 (the length of the TiN layer dissolved by hydrogen peroxide solution) was used as the comparison standard. It can be said that the greater the damage, the lower the resistance to the wet etching solution using hydrogen peroxide solution (the lower the protective effect of the protective film on the TiN layer).

[0140]

[0141] From the above results, when Examples 3 and 4, which used compound (B) represented by formula (B) as an additive, were compared with Comparative Example 2, which did not use such compound (B), damage to the TiN layer caused by hydrogen peroxide solution was less in Examples 3 and 4. That is, from the results of Examples 3 and 4, it was found that by employing compound (B) represented by formula (B) as an additive, the TiN layer exhibited better resistance to a wet etching solution using hydrogen peroxide solution than Comparative Example 2, which did not employ such compound (B), and therefore is useful as a protective film against a wet etching solution for semiconductors.

[0142] 1 substrate 2 TiN layer 3 protective film 4 resist film L length

Claims

1. A composition for forming a protective film for forming a protective film that protects an inorganic film formed on a surface of a semiconductor substrate from wet etching, the composition comprising: a compound (A) having a partial structure represented by the following formula (A-1) and a partial structure represented by the following formula (A-2); a compound (B) represented by the following formula (B); and a solvent. (In formula (A-1), X １ and X ２ each independently represents a single bond or a carbonyl group. １ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond. In formula (A-2), each A independently represents a hydrogen atom, a methyl group, or an ethyl group. Q ２ represents a divalent organic group having 1 to 20 carbon atoms. * represents a bond. (In formula (B), n represents an integer of 2 to 10. When n is 2, X represents a sulfinyl group, a sulfonyl group, an ether group, or a divalent organic group having 2 to 50 carbon atoms. When n is an integer other than 2, X represents an n-valent organic group having 2 to 50 carbon atoms. Y represents a single bond or a divalent linking group having 1 to 12 carbon atoms.) 2. The composition for forming a protective film according to claim 1, wherein X in formula (B) is an n-valent organic group having a ring structure and 2 to 50 carbon atoms.

3. The composition for forming a protective film according to claim 1, wherein X in formula (B) is any of the structures shown below. (In the formula, * represents a bond.) 4. The composition for forming a protective film according to claim 1, wherein Y in formula (B) is a divalent linking group having 1 to 12 carbon atoms and represented by the following formula (Y-1): (In formula (Y-1), R １ represents a single bond or an alkylene group having 1 to 4 carbon atoms. １ represents a single bond, an ether group, or an ester group. ２ represents an alkylene group having 1 to 8 carbon atoms, a phenylene group, -(C ｎ H ２ｎ O) ｍ -(n represents 2 or 3, and m represents 2 or 3), or -CH ２ -CH(OH)-CH ２ - represents X ２ represents a single bond, an ether group, or an ester group. ３ represents a single bond, an alkylene group having 1 to 8 carbon atoms, or a group represented by the following formula (Y-1-1). *1 represents a bond bonded to X in formula (B). *2 represents a bond bonded to the benzene ring in formula (B). However, the total number of carbon atoms is 1 to 12. (In formula (Y-1-1), *3 represents a bond bonding to the benzene ring in formula (B). * represents a bond.) 5. The composition for forming a protective film according to claim 1, wherein the compound (A) has, as the partial structure represented by formula (A-1), at least one of a structure represented by formula (A-1-1) below and a structure represented by formula (A-1-2) below: (In formula (A-1-1), Q １１ represents an alkylene group having 1 to 10 carbon atoms. * represents a bond. In formula (A-1-2), Q １２ represents a divalent organic group having 1 to 20 carbon atoms and at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen in the main chain. * represents a bond.

6. The composition for forming a protective film according to claim 1, wherein the compound (A) has a structure represented by the following formula (A-2-1) as the partial structure represented by the formula (A-2): (In formula (A-2-1), X １１ represents a divalent group represented by the following formula (A-2-1-1), (A-2-1-2) or (A-2-1-3). １ and Z ２ each independently represents a single bond or a divalent group represented by the following formula (A-2-1-4): A each independently represents a hydrogen atom, a methyl group, or an ethyl group; * represents a bond. (In formulas (A-2-1-1) to (A-2-1-3), R １ ~R ５ R each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkenyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, an alkynyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom or a sulfur atom, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one monovalent group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms. １ and R ２ may be bonded to each other to form a ring having 3 to 6 carbon atoms. ３ and R ４ may be bonded to each other to form a ring having 3 to 6 carbon atoms. * represents a bond. *1 represents a bond bonded to a carbon atom. *2 represents a bond bonded to a nitrogen atom. (In formula (A-2-1-4), m1 is an integer of 1 to 4, m2 is 0 or 1, *3 represents a bond bonded to a nitrogen atom, and *4 represents a bond bonded to a carbon atom.) 7. A protective film against a wet etching solution for semiconductors, which is a fired product of a coating film made of the composition for forming a protective film according to any one of claims 1 to 6.

8. A method for producing a substrate with a protective film, comprising the steps of applying the composition for forming a protective film according to any one of claims 1 to 6 onto a semiconductor substrate having a step and baking the composition to form a protective film.

9. A method for manufacturing a substrate with a resist pattern, used in the manufacture of semiconductors, comprising the steps of: applying a composition for forming a protective film according to any one of claims 1 to 6 onto a semiconductor substrate and baking the composition to form a protective film as a resist underlayer film; and forming a resist film on the protective film directly or via another layer, followed by exposure and development to form a resist pattern.

10. A method for manufacturing a semiconductor device, comprising the steps of forming a protective film on a semiconductor substrate having an inorganic film formed on its surface using a protective film-forming composition according to any one of claims 1 to 6, forming a resist pattern on the protective film directly or via another layer, dry-etching the protective film using the resist pattern as a mask to expose the surface of the inorganic film, and wet-etching the inorganic film using a semiconductor wet etching solution using the protective film after dry etching as a mask.

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