Chemical-resistant protective film-forming composition containing a polymerization product having a diol structure at the end

Abstract

To provide a protective film forming composition which has superior masking (protection) functions against wet etching liquids and a high dry etching rate during semiconductor substrate processing and also provides good coverage, even on stepped substrates, enabling the formation of a flat film with minimal thickness variation after embedding; a protective film produced using the composition; a substrate with a resist pattern; and a method for manufacturing a semiconductor device.SOLUTION: A protective film forming composition against a wet etching liquid for semiconductors contains an organic solvent and a polymer having, at a terminal thereof, a structure containing at least one pair of two adjacent hydroxy groups in the molecule. The structure containing two adjacent hydroxy groups in the molecule may be 1,2-ethanediol structure (A).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, primarily by dry etching, although wet etching may also be used depending on the type of substrate. Patent Document 1 discloses a protective film-forming composition for an aqueous hydrogen peroxide solution, which contains a specific compound containing a carboxyl group and / or a hydroxyl group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 052130 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 the underlying substrate by wet etching, the resist underlayer film is required to have good masking function against the wet etching solution during processing of the underlying substrate (i.e., the masked portion can protect the substrate).

[0005] In such cases, the resist underlayer film is used as a protective film for the substrate. Furthermore, when the unnecessary protective film is to be removed by dry etching after wet etching, the protective film is required to have a high etching rate (high etching rate) so that it can be quickly removed by dry etching without damaging the underlying substrate.

[0006] Furthermore, there is a demand for a protective film-forming composition that has good coating properties even on uneven substrates, has small film thickness differences after filling, and is capable of forming a flat film.

[0007] 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-mentioned problems.

[0008] An object of the present invention is to solve the above problems. [Means for solving the problem]

[0009] The present invention encompasses the following. [1] A protective film-forming composition for a semiconductor wet etching solution, comprising a polymer having a structure containing at least one pair of adjacent hydroxyl groups in the molecule at its terminal, and an organic solvent. [2] The protective film-forming composition according to [1], wherein the structure containing at least one pair of two adjacent hydroxyl groups in the molecule is a 1,2-ethanediol structure (A). [3] The 1,2-ethanediol structure is represented by formula (1): [ka] (In formula (1), X represents any of -COO-, -OCO-, -O-, -S-, or -NR1-, R1 represents a hydrogen atom or a methyl group, Y represents a direct bond or an optionally substituted alkylene group having 1 to 4 carbon atoms, R2, R3, and R4 each represent a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 40 carbon atoms, and R2 may form a ring together with R3 or R4.) The protective film-forming composition according to [2], which contains a structure represented by the following formula: [4] The protective film-forming composition according to [3], wherein in the formula (1), R2, R3, and R4 are hydrogen atoms. [5] The protective film-forming composition according to [3] or [4], wherein in the formula (1), Y is a methylene group. [6] The protective film-forming composition according to any one of [3] to [5], wherein in the formula (1), X is —S—. [7] The protective film-forming composition according to any one of [1] to [6], wherein the polymer is a reaction product of a diepoxy compound (B) and a di- or higher functional proton-generating compound (C). [8] The protective film-forming composition according to [7], wherein the bifunctional or higher functional proton-generating compound (C) has at least one functional group selected from a hydroxyl group, a carboxyl group, a thiol group, an amino group, and an imide group. [9] The protective film-forming composition according to [7], wherein the bifunctional or higher functional proton-generating compound (C) is an acid dianhydride.

[10] The polymer is represented by the following formula (2): [ka] (In formula (2), R5, R6, R7, R8, R9 and R 10 each independently represents a hydrogen atom, a methyl group, or an ethyl group; Q1 represents a divalent organic group between two carbon atoms; and m1 and m2 each independently represent 0 or 1. is expressed as portion The protective film-forming composition according to any one of [1] to [9], which comprises a structure.

[11] Q1 in the formula (2) is the following formula (3): [ka] (In formula (3), Q2 represents a direct bond, an alkylene group having 1 to 10 carbon atoms which may be interrupted by -O-, -S- or -SS-, an alkenylene group having 2 to 6 carbon atoms which may be interrupted by -O-, -S- or -SS-, or a divalent organic group having at least one alicyclic hydrocarbon ring having 3 to 10 carbon atoms or one aromatic hydrocarbon ring having 6 to 14 carbon atoms; The divalent organic group may be substituted with at least one group selected from the group consisting of 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 halogen atom, a hydroxy group, a nitro group, a cyano group, a methylidene group, an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, and an alkylthio group having 1 to 6 carbon atoms. Z1 and Z2 each represent -COO-, -OCO-, -O-, or -S-. The protective film-forming composition according to

[10] ,

[12] Q1 in the formula (2) is the following formula (4): [ka] (In formula (4), Q3 represents the following formula (5), formula (6), or formula (7).) [ka] (In formula (5), formula (6) and formula (7), R 11 , R 12 , R 13 , R 14 and R 15 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group; the phenyl group is optionally substituted with at least one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a cyano group, an alkoxy group having 1 to 6 carbon atoms, and an alkylthio group having 1 to 6 carbon atoms; R 13 and R 14 may be bonded to each other to form a ring having 3 to 6 carbon atoms. The protective film-forming composition according to

[10] ,

[13] The protective film-forming composition according to any one of [1] to

[12] , further comprising a crosslinking catalyst.

[14] The protective film-forming composition according to any one of [1] to

[13] , further comprising a crosslinking agent.

[15] The protective film-forming composition according to any one of [1] to

[14] , further comprising a surfactant.

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

[15] .

[17] 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

[15] 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 semiconductors.

[18] A method for manufacturing a semiconductor device, comprising the steps of forming a protective film on a semiconductor substrate, which may have an inorganic film formed on its surface, using the protective film-forming composition according to any one of [1] to

[15] , forming a resist pattern on the protective film, dry-etching the protective film using the resist pattern as a mask to expose the surface of the inorganic film or the semiconductor substrate, and wet-etching and cleaning the inorganic film or the semiconductor substrate using a semiconductor wet etching solution using the protective film after dry etching as a mask. [Effects of the Invention]

[0010] In the lithography process of semiconductor manufacturing, a protective film-forming composition is required to have, for example, the following properties in a good balance: (1) good masking function against a wet etching solution when processing an underlying substrate, (2) a high dry etching rate, and (3) excellent planarization ability for uneven substrates. The protective film-forming composition of the present invention has these properties (1) to (3) in a good balance, thereby facilitating microfabrication of semiconductor substrates. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Terminology> Terms used in the present invention have the following definitions unless otherwise specified.

[0012] Examples of the "C1-C10 alkylene group" 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, a 1-ethyl-n- 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 group, 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.

[0013] Examples of the "C1-C10 alkyl group" include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 1-ethyl-n-propyl group, cyclopentyl, 1-methylcyclobutyl, 2-methylcyclobutyl, 3-methylcyclobutyl, 1,2-dimethylcyclopropyl, 2,3-dimethylcyclopropyl, 1-ethylcyclopropyl, 2-ethylcyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2, 2-dimethyl-n-butyl 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, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and icodecyl group.

[0014] Examples of the "aryl group having 6 to 40 carbon atoms" include a phenyl group, an o-methylphenyl group, a m-methylphenyl group, a p-methylphenyl group, an o-chlorophenyl group, a m-chlorophenyl group, a p-chlorophenyl group, an o-fluorophenyl group, a p-fluorophenyl group, an o-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, a p-cyanophenyl group, an α-naphthyl group, a β-naphthyl group, an o-biphenylyl group, a m-biphenylyl group, a p-biphenylyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group.

[0015] Examples of the "alkenyl group having 2 to 10 carbon atoms" include ethenyl, 1-propenyl, 2-propenyl, 1-methyl-1-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylethenyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2 -ethyl-2-propenyl group, 2-methyl-1-butenyl group, 2-methyl-2-butenyl group, 2-methyl-3-butenyl group, 3-methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propylethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl-2-propenyl group, 1-methyl-2-propenyl group, 1-methyl-2-but ... ethyl-1-pentenyl group, 1-methyl-2-pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butylethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group, 2-methyl-3-pentenyl group, 2-methyl-4-pentenyl group, 2-n-propyl-2-propenyl group, 3-methyl-1-pentenyl group, 3-methyl-2-pentenyl group, 3-methyl-3-pentenyl group, 3-methyl-4-pentenyl group, 3-ethyl-3-butenyl group, 4-methyl-1-pentenyl group, 4-methyl-2-pentenyl group group, 4-methyl-3-pentenyl group, 4-methyl-4-pentenyl group, 1,1-dimethyl-2-butenyl group, 1,1-dimethyl-3-butenyl group, 1,2-dimethyl-1-butenyl group, 1,2-dimethyl-2-butenyl group, 1,2-dimethyl-3-butenyl group, 1-methyl-2-ethyl-2-propenyl group, 1-s-butylethenyl group, 1,3-dimethyl-1-butenyl group, 1,3-dimethyl-2-butenyl group, 1,3-dimethyl-3-butenyl group, 1-i-butylethenyl group, 2,2-dimethyl-3-butenyl group, 2,3-dimethyl-1-butenyl group, 2,3-dimethyl-2-butenyl group, 2,3-dimethyl-3-butenyl group, 2-i-propyl-2-propenyl group, 3,3-dimethyl-1-butenyl group, 1-ethyl-1-butenyl group, 1-ethyl-2-butenyl group, 1-ethyl-3-butenyl group, 1-n-propyl-1-propenyl group, 1-n-propyl-2-propenyl group, 2-ethyl-1-butenyl group, 2-ethyl-2-butenyl group, 2-ethyl-3-butenyl group, 1,1,2-trimethyl-2-propenyl group, 1-t-butylethenyl group, 1-methyl-1-ethyl-2-propenyl group, 1-ethyl-2-methyl-1-propenyl group, 1-ethyl-2-methyl-2-propenyl group, 1-i-propyl-1-propenyl group, 1-i- Examples of such alkyl groups include propyl-2-propenyl group, 1-methyl-2-cyclopentenyl group, 1-methyl-3-cyclopentenyl group, 2-methyl-1-cyclopentenyl group, 2-methyl-2-cyclopentenyl group, 2-methyl-3-cyclopentenyl group, 2-methyl-4-cyclopentenyl group, 2-methyl-5-cyclopentenyl group, 2-methylene-cyclopentyl group, 3-methyl-1-cyclopentenyl group, 3-methyl-2-cyclopentenyl group, 3-methyl-3-cyclopentenyl group, 3-methyl-4-cyclopentenyl group, 3-methyl-5-cyclopentenyl group, 3-methylene-cyclopentyl group, 1-cyclohexenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group.

[0016] The term "C 2-6 alkenylene group" refers to a divalent group obtained by removing one hydrogen atom from an alkenyl group having 2 to 6 carbon atoms, such as the above-mentioned "C 2-10 alkenyl group."

[0017] Examples of the "alicyclic hydrocarbon ring having 3 to 10 carbon atoms" include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, spirobicyclopentane, bicyclo[2.1.0]pentane, bicyclo[3.2.1]octane, tricyclo[3.2.1.0]octane, and cyclopentane. 2,7 ]octane, spiro[3,4]octane, etc.

[0018] The term "aromatic hydrocarbon ring having 6 to 14 carbon atoms" refers to the above-mentioned "aryl group having 6 to 40 carbon atoms" which has an aromatic hydrocarbon ring having 6 to 14 carbon atoms.

[0019] The term "C2-C6 alkynyl group" refers to a group in which the double bond of the C2-C6 alkenyl group enumerated above as the "C2-C10 alkenyl group" is replaced with a triple bond.

[0020] Examples of the "alkoxy group having 1 to 20 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-pentyloxy 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 1,1-dimethyl-n-butoxy group, a 1, Examples of such groups include a 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, a cyclopentyloxy group, a cyclohexyloxy group, a norbornyoxy group, an adamantyloxy group, an adamantanemethyloxy group, an adamantaneethyloxy group, a tetracyclodecanyloxy group, and a tricyclodecanyloxy group.

[0021] Examples of the "alkoxycarbonyl group having 1 to 6 carbon atoms" include a methoxycarbonyl group, an ethoxycarbonyl group, and an isopropoxycarbonyl group.

[0022] Examples of the "alkylthio group having 1 to 6 carbon atoms" include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, and a hexylthio group.

[0023] "Halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0024] Examples of the "alkoxy group having 1 to 20 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-pentyloxy 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 1,1-dimethyl-n-butoxy group, a 1, Examples of such groups include a 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, a cyclopentyloxy group, a cyclohexyloxy group, a norbornyloxy group, an adamantyloxy group, an adamantanemethyloxy group, an adamantaneethyloxy group, a tetracyclodecanyloxy group, and a tricyclodecanyloxy group.

[0025] The term "optionally substituted" means that some or all of the hydrogen atoms present in the alkyl group having 1 to 10 carbon atoms or the aryl group having 6 to 40 carbon atoms may be substituted with, for example, a hydroxyl group, a halogen atom, a carboxyl group, a nitro group, a cyano group, a methylenedioxy group, an acetoxy group, a methylthio group, an amino group, or an alkoxy group having 1 to 9 carbon atoms.

[0026] <Protective film forming composition> The protective film-forming composition of the present application is a protective film-forming composition for a semiconductor wet etching solution, which comprises a polymer having a structure containing at least one pair of adjacent hydroxyl groups in the molecule at its terminal, and an organic solvent. The following will explain each of the following in order.

[0027] <Structure containing at least one pair of adjacent hydroxyl groups in the molecule> The structure containing at least one pair of two adjacent hydroxyl groups in the molecule may be a 1,2-ethanediol structure (A).

[0028] The 1,2-ethanediol structure is represented by formula (1): [ka]

[0029] (In formula (1), X represents any of -COO-, -OCO-, -O-, -S-, or -NR1-, R1 represents a hydrogen atom or a methyl group, Y represents an alkylene group having 1 to 4 carbon atoms which may be substituted, R2, R3, and R4 each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted, or an aryl group having 6 to 40 carbon atoms, and R2 may combine with R3 or R4 to form a ring.) It may include a structure represented by:

[0030] Specific examples of the ring formed by R2 together with R3 or R4 include a cyclopentane ring, a cyclohexane ring, and a bicyclo[2,2,1]heptane ring.

[0031] When the above ring is formed, it can be derived by reacting a compound such as cyclopentane-1,2-diol, cyclohexane-1,2-diol, or bicyclo[2,2,1]heptane-1,2-diol with the polymer terminal.

[0032] In the formula (1), R2, R3 and R4 may be hydrogen atoms. In the formula (1), Y may be a methylene group. In the formula (1), X may be —S—.

[0033] Examples of the compound that forms the terminal of the polymer having the 1,2-ethanediol structure (A) include compounds represented by the following formulae (A-1) to (A-4).

[0034] [ka]

[0035] <Polymer> The polymer may be a reaction product of a diepoxy compound (B) and a di- or higher functional proton-generating compound (C).

[0036] The reaction product is represented by the following formula (2): [ka]

[0037] (In formula (2), R5, R6, R7, R8, R9 and R 10 each independently represents a hydrogen atom, a methyl group, or an ethyl group; Q1 represents a divalent organic group between two carbon atoms; and m1 and m2 each independently represent 0 or 1. is expressed as portion It may also include a structure.

[0038] Q1 in the formula (2) is the following formula (3): [ka]

[0039] (In formula (3), Q2 represents a direct bond, an alkylene group having 1 to 10 carbon atoms which may be interrupted by -O-, -S-, or -SS-, an alkenylene group having 2 to 6 carbon atoms, or a divalent organic group having at least one alicyclic hydrocarbon ring having 3 to 10 carbon atoms or an aromatic hydrocarbon ring having 6 to 14 carbon atoms, and the divalent organic group is optionally substituted with at least one group selected from the group consisting of 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 halogen atom, a hydroxy group, a nitro group, a cyano group, a methylidene group, an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, and an alkylthio group having 1 to 6 carbon atoms; and Z1 and Z2 each represent -COO-, -OCO-, -O-, or -S-.) It may be expressed as:

[0040] Q1 in the formula (2) is the following formula (4): [ka]

[0041] (In formula (4), Q3 represents the following formula (5), formula (6), or formula (7).) [ka]

[0042] (In formula (5), formula (6) and formula (7), R 11 , R 12 , R 13 , R 14 and R 15 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group is optionally substituted with at least one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a cyano group, an alkoxy group having 1 to 6 carbon atoms, and an alkylthio group having 1 to 6 carbon atoms; R13 and R 14 may be bonded to each other to form a ring having 3 to 6 carbon atoms. It may be expressed as:

[0043] Examples of the diepoxy compound (B) that forms a structural unit represented by the formula (2) in which m1 and m2 represent 1 include, but are not limited to, compounds having diglycidyl ethers or diglycidyl esters each having two epoxy groups, as represented by the following formulas (B-1) to (B-46).

[0044] [ka]

[0045] [ka]

[0046] Examples of the bifunctional or higher functional proton-generating compound (C) that forms a structural unit represented by the formula (2) in which m1 and m2 are 0 include compounds having two carboxyl groups, hydroxyphenyl groups, or imide groups, and acid dianhydrides, which are represented by the following formulae (C-1) to (C-47), but are not limited to these examples.

[0047] [ka]

[0048] [ka]

[0049] [Crosslinking agent] The resist underlayer film-forming composition of the present invention may contain a crosslinker component. Examples of such crosslinkers include melamine-based crosslinkers, substituted urea-based crosslinkers, and polymers thereof. A crosslinker having at least two crosslink-forming substituents is preferred, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensates of these compounds may also be used.

[0050] 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.

[0051] Such compounds include compounds having a partial structure of the following formula (5-1) and polymers or oligomers having a repeating unit of the following formula (5-2). [ka]

[0052] Above R 11 , R 12 , R 13 , and R 14 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and specific examples of these alkyl groups are as described above.

[0053] m1 is 1≦m1≦6−m2, m2 is 1≦m2≦5, m3 is 1≦m3≦4−m2, and m4 is 1≦m4≦3.

[0054] Examples of the compounds, polymers and oligomers of formula (5-1) and formula (5-2) are shown below. [ka]

[0055] [ka]

[0056] The above compounds are available as products of Asahi Organic Chemicals Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above crosslinking agents, the compound of formula (6-22) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TMOM-BP.

[0057] 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 usually 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.

[0058] [Crosslinking catalyst] The protective film-forming composition of the present invention may contain, as an optional component, a crosslinking catalyst to promote the crosslinking reaction. The crosslinking catalyst may be an acidic compound, a basic compound, or a compound that generates an acid or a base upon heating, but a crosslinking acid catalyst is preferred. The acidic compound may be a sulfonic acid compound or a carboxylic acid compound, and the compound that generates an acid upon heating may be a thermal acid generator.

[0059] Examples of sulfonic acid compounds or carboxylic acid compounds include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium trifluoromethanesulfonate, pyridinium-p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-phenolsulfonic acid, pyridinium-4-phenolsulfonate, benzenedisulfonic acid, 1-naphthalenesulfonic acid, 4-nitrobenzenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

[0060] Examples of thermal acid generators include K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, and TAG2689 (all manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (all manufactured by Sanshin Chemical Industry Co., Ltd.).

[0061] These crosslinking catalysts can be used alone or in combination of two or more. As the basic compound, an amine compound or an ammonium hydroxide compound can be used, and as the compound that generates a base by heat, urea can be used.

[0062] Examples of amine compounds include tertiary amines such as triethanolamine, tributanolamine, trimethylamine, triethylamine, tri-normal propylamine, triisopropylamine, tri-normal butylamine, tri-tert-butylamine, tri-normal octylamine, triisopropanolamine, phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, and aromatic amines such as pyridine and 4-dimethylaminopyridine. Other examples of amine compounds include primary amines such as benzylamine and normal butylamine, and secondary amines such as diethylamine and di-normal butylamine. These amine compounds can be used alone or in combination.

[0063] Examples of ammonium hydroxide compounds include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, cetyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, and phenyltriethylammonium hydroxide.

[0064] Examples of compounds that generate a base upon heating include compounds that have a thermolabile group such as an amide group, a urethane group, or an aziridine group and generate an amine upon heating. Other examples of compounds that generate a base upon heating include urea, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylphenylammonium chloride, benzyldodecyldimethylammonium chloride, benzyltributylammonium chloride, and choline chloride.

[0065] When the protective film-forming composition contains a crosslinking catalyst, the content thereof is usually 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.

[0066] [Surfactants] 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 usually 0.0001 to 10 wt %, preferably 0.01 to 5 wt %, based on the total solid content of the protective film-forming composition.

[0067] [solvent] The protective film-forming composition of the present invention can be prepared by dissolving the above-mentioned components in an organic solvent, and is used in the form of a homogeneous solution.

[0068] The solvent for the protective film-forming composition of the present invention is not particularly limited, as long as it can dissolve the compound containing at least one pair of two adjacent hydroxyl groups in the molecule, or a polymer thereof. In particular, since the protective film-forming composition of the present invention is used in the form of a homogeneous solution, it is recommended to use a solvent commonly used in lithography processes in combination with the composition, taking into account its coating performance.

[0069] 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.

[0070] 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.

[0071] [Other ingredients] The protective film-forming composition of the present invention may contain a light absorber, a rheology modifier, an adhesion promoter, etc. The rheology modifier is effective in improving the fluidity of the protective film-forming composition. The adhesion promoter is effective in improving the adhesion between the semiconductor substrate or resist and the underlayer film.

[0072] Examples of the light-absorbing agent include commercially available light-absorbing agents described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as CI Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; CI Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; CI Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; CI Disperse Violet 43; CI Disperse Blue 96; and CI Fluorescent Brightening Agent. 112, 135 and 163; CI Solvent Orange 2 and 45; CI Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49; CI Pigment Green 10; CI Pigment Brown 2, etc. can be suitably used.

[0073] The light absorbing agent is usually blended in an amount of 10% by mass or less, preferably 5% by mass or less, based on the total solid content of the protective film-forming composition.

[0074] Rheology modifiers are added primarily to improve the fluidity of the protective film-forming composition, particularly during the baking process, to improve the film thickness uniformity of the resist underlayer film and the ability of the protective film-forming composition to fill holes. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically incorporated in an amount of less than 30% by mass based on the total solids content of the protective film-forming composition.

[0075] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the protective film-forming composition, and particularly to prevent the resist from peeling off during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylmethylolchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylmethylolethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; methyloltrimethylsilane; and methyloltrimethylsilane. Examples of suitable adhesion promoters include silanes such as chlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters are typically blended in an amount of less than 5% by mass, and preferably less than 2% by mass, based on the total solids content of the protective film-forming composition.

[0076] [Protective film forming composition] The solids content of the protective film-forming composition according to the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solids content is the content of all components of the protective film-forming composition excluding the solvent. The proportion of polymer in the solids content is preferably 1 to 100% by mass, 1 to 99.9% by mass, 50 to 99.9% by mass, 50 to 95% by mass, and 50 to 90% by mass, in that order.

[0077] [Method of manufacturing a substrate with a resist pattern and a semiconductor device] Hereinafter, a method for producing a substrate having a resist pattern and a method for producing a semiconductor device using the protective film-forming composition according to the present invention will be described.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] The protective film-forming composition of the present invention is applied to such a semiconductor substrate using an appropriate application method such as a spinner or coater. A protective film is then formed by baking using a heating means such as a hot plate. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 120°C to 350°C and the baking time is 0.5 to 30 minutes, more preferably, the baking temperature is 150°C to 300°C and the baking time is 0.8 to 10 minutes. The thickness of the formed protective film is, for example, 0.001 μm to 10 μm, preferably 0.002 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm. If the baking temperature is lower than the above range, crosslinking may be insufficient, and the formed protective film may not be resistant to resist solvents or basic hydrogen peroxide aqueous solutions. On the other hand, if the baking temperature is higher than the above range, the protective film may be thermally decomposed.

[0082] Exposure is performed through a mask (reticle) to form 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 appropriately selected from 5°C to 50°C and the development time appropriately selected from 10 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, the aqueous solutions of the above alkalis can also be used by adding an appropriate amount of alcohols such as isopropyl alcohol or a nonionic surfactant. Among these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants and the like can be added to these developers. Alternatively, development can be carried out with an organic solvent such as butyl acetate instead of an alkaline developer to develop the portions of the photoresist where the alkaline dissolution rate is not improved.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] Among these, acidic hydrogen peroxide solution or basic hydrogen peroxide solution is preferred.

[0089] These chemical solutions may contain additives such as surfactants.

[0090] The temperature of the semiconductor wet etching solution is preferably 25° C. to 90° C., and more preferably 40° C. to 80° C. The wet etching time is preferably 0.5 to 30 minutes, and more preferably 1 to 20 minutes. [Example]

[0091] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0092] The apparatus used to measure the weight-average molecular weight of the polymers obtained in the following synthesis examples is shown below. Apparatus: Tosoh Corporation HLC-8320GPC GPC column: Shodex (registered trademark) Asahipak (registered trademark) (Showa Denko K.K.) Column temperature: 40℃ Flow rate: 0.35mL / min Eluent: tetrahydrofuran (THF) Standard sample: Polystyrene (Tosoh Corporation)

[0093] Example 1 A reaction flask containing 13.00 g of diglycidyl methylisocyanurate (product name: MeDGIC, manufactured by Shikoku Chemicals Corporation, 49.2 wt% propylene glycol monomethyl ether solution), 2.36 g of succinic acid, 1.08 g of 1-thioglycerol, 0.64 g of tetrabutylphosphonium bromide, and 35.27 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-1), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 1400.

[0094] [ka]

[0095] A solution of a protective film-forming composition was prepared by adding 4.26 g of a solution of the reaction product corresponding to the formula (D-1) (solid content: 17.3 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.67 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0096] <Example 2> A reaction flask containing 8.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 2.61 g of succinic acid, 1.19 g of 1-thioglycerol, 0.70 g of tetrabutylphosphonium bromide, and 50.01 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-2), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 3700.

[0097] [ka]

[0098] A solution of a protective film-forming composition was prepared by adding 4.45 g of a solution of the reaction product corresponding to the formula (D-2) (solid content: 16.6 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.48 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0099] Example 3 A reaction flask containing 7.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 4.06 g of 3,3'-dithiopropionic acid, 1.04 g of 1-thioglycerol, 0.41 g of tetrabutylphosphonium bromide, and 50.06 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-3), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 4300.

[0100] [ka]

[0101] A solution of a protective film-forming composition was prepared by adding 4.85 g of a solution of the reaction product corresponding to the formula (D-3) (solid content: 15.2 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.08 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0102] Example 4 A reaction flask containing 8.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 3.31 g of 2,2'-thiodiglycolic acid, 1.19 g of 1-thioglycerol, 0.47 g of tetrabutylphosphonium bromide, and 51.90 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-4), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 2700.

[0103] [ka]

[0104] A solution of a protective film-forming composition was prepared by adding 4.43 g of a solution of the reaction product corresponding to the formula (D-4) (solid content: 16.6 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.50 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0105] <Example 5> A reaction flask containing 8.00 g of phthalic acid diglycidyl ester (product name: Denacol EX-721, manufactured by Nagase ChemteX Corporation), 2.47 g of succinic acid, 1.13 g of 1-thioglycerol, 0.66 g of tetrabutylphosphonium bromide, and 49.03 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-5), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 2100.

[0106] [ka]

[0107] A solution of a protective film-forming composition was prepared by adding 4.58 g of a solution of the reaction product corresponding to the formula (D-5) (solid content: 16.1 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.35 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0108] Example 6 A reaction flask containing 14.00 g of resorcinol diglycidyl ether (product name: Denacol EX-201-IM, manufactured by Nagase ChemteX Corporation, 50.0 wt% propylene glycol monomethyl ether solution), 2.84 g of succinic acid, 1.30 g of 1-thioglycerol, and 0.76 g of tetrabutylphosphonium bromide was heated with stirring at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-6), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 3600.

[0109] [ka]

[0110] A solution of a protective film-forming composition was prepared by adding 4.54 g of a solution of the reaction product corresponding to the formula (D-6) (solid content: 16.2 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.38 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0111] Example 7 A reaction flask containing 12.00 g of resorcinol diglycidyl ether (product name: Denacol EX-201-IM, manufactured by Nagase ChemteX Corporation, 50.0 wt% propylene glycol monomethyl ether solution), 4.33 g of 3,3'-dithiopropionic acid, 1.11 g of 1-thioglycerol, and 0.44 g of tetrabutylphosphonium bromide was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-7), and its weight-average molecular weight Mw measured by GPC relative to polystyrene standards was 4700.

[0112] [ka]

[0113] A solution of a protective film-forming composition was prepared by adding 4.57 g of a solution of the reaction product corresponding to the formula (D-7) (solid content: 16.1 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.36 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0114] Example 8 A reaction flask containing 13.00 g of resorcinol diglycidyl ether (product name: Denacol EX-201-IM, manufactured by Nagase ChemteX Corporation, 50.0 wt% propylene glycol monomethyl ether solution), 3.35 g of 2,2'-thiodiglycolic acid, 1.21 g of 1-thioglycerol, and 0.47 g of tetrabutylphosphonium bromide, and 39.61 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (D-8), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 1900.

[0115] [ka]

[0116] A solution of a protective film-forming composition was prepared by adding 4.45 g of a solution of the reaction product corresponding to the formula (D-8) (solid content: 16.6 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.48 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0117] <Comparative Example 1> A reaction flask containing 10.00 g of diglycidyl methylisocyanurate (product name: MeDGIC, manufactured by Shikoku Chemicals Corporation, 49.2 wt% propylene glycol monomethyl ether solution), 2.72 g of succinic acid, 0.49 g of tetrabutylphosphonium bromide, and 27.44 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-1), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 1400.

[0118] [ka]

[0119] A solution of a protective film-forming composition was prepared by adding 4.21 g of a solution of the reaction product corresponding to the formula (E-1) (solid content: 17.5 wt%), 0.15 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.72 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate.

[0120] <Comparative Example 2> A reaction flask containing 10.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 4.89 g of succinic acid, 0.64 g of ethyltriphenylphosphonium bromide, and 62.11 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-2), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 3100.

[0121] [ka]

[0122] A solution of a protective film-forming composition was prepared by adding 4.03 g of a solution of the reaction product corresponding to the formula (E-2) (solid content: 16.3 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.91 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0123] <Comparative Example 3> A reaction flask containing 10.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 8.70 g of 3,3'-dithiopropionic acid, 0.31 g of benzyltriethylammonium chloride, and 107.76 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-3), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 3200.

[0124] [ka]

[0125] A solution of a protective film-forming composition was prepared by adding 4.04 g of a solution of the reaction product corresponding to the formula (E-3) (solid content: 16.2 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.89 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0126] <Comparative Example 4> A reaction flask containing 10.00 g of terephthalic acid diglycidyl ester (product name: Denacol EX-711, manufactured by Nagase ChemteX Corporation), 6.21 g of 2,2'-thiodiglycolic acid, 0.64 g of ethyltriphenylphosphonium bromide, and 67.42 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 23 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-4), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 2700.

[0127] [ka]

[0128] A solution of a protective film-forming composition was prepared by adding 3.93 g of a solution of the reaction product corresponding to the formula (E-4) (solid content: 16.7 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 14.00 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0129] <Comparative Example 5> A reaction flask containing 10.00 g of phthalic acid diglycidyl ester (product name: Denacol EX-721, manufactured by Nagase ChemteX Corporation), 4.62 g of succinic acid, 0.61 g of ethyltriphenylphosphonium bromide, and 60.91 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 27 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-5), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 1900.

[0130] [ka]

[0131] A solution of a protective film-forming composition was prepared by adding 4.07 g of a solution of the reaction product corresponding to the formula (E-5) (solid content: 16.1 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.87 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0132] <Comparative Example 6> A reaction flask containing 10.00 g of resorcinol diglycidyl ether (product name: Denacol EX-201-IM, manufactured by Nagase ChemteX Corporation), 6.09 g of succinic acid, 0.80 g of ethyltriphenylphosphonium bromide, and 67.55 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 27 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-6), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 3,000.

[0133] [ka]

[0134] A solution of a protective film-forming composition was prepared by adding 3.93 g of a solution of the reaction product corresponding to the formula (E-6) (solid content: 16.7 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.94 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0135] <Comparative Example 7> A solution of 5.00 g of glycidyl methacrylate, 5.21 g of 5-vinylbenzo[d][1,3]dioxole (manufactured by Cool Pharm LTD.), 0.58 g of 2,2'-azobis(isobutyronitrile), and 34.53 g of propylene glycol monomethyl ether was added to a dropping funnel, and the mixture was added dropwise to a reaction flask containing 8.63 g of propylene glycol monomethyl ether at 100°C under a nitrogen atmosphere and heated with stirring for 20 hours. The resulting reaction product corresponded to formula (E-7), and its weight-average molecular weight Mw measured by GPC in terms of polystyrene was 9000.

[0136] [ka]

[0137] A solution of a protective film-forming composition was prepared by adding 4.06 g of a solution of the reaction product corresponding to the formula (E-7) (solid content: 16.1 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 13.87 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0138] <Comparative Example 8> A solution of 16.00 g of glycidyl methacrylate, 4.53 g of 2,2'-azobis(isobutyronitrile), and 65.68 g of propylene glycol monomethyl ether was added to a dropping funnel and added dropwise to a reaction flask containing 16.48 g of propylene glycol monomethyl ether at 100 °C under a nitrogen atmosphere, followed by heating and stirring for 13 hours. To 30.00 g of the resulting solution (epoxy value 676 g / eq), 5.31 g of 3,4-dihydroxybenzoic acid, 0.20 g of benzyltriethylammonium chloride, and 17.89 g of propylene glycol monomethyl ether were added and heated under reflux and stirring for 20 hours under a nitrogen atmosphere. The resulting reaction product corresponded to formula (E-8), and its weight-average molecular weight (Mw) measured by GPC relative to polystyrene standards was 24,400.

[0139] [ka]

[0140] A solution of a protective film-forming composition was prepared by adding 3.36 g of a solution of the reaction product corresponding to the formula (E-8) (solid content: 19.5 wt%), 0.13 g of 3,3',5,5'-tetrakis(methoxymethyl)-4,4'-dihydroxybiphenyl (product name: TMOM-BP, manufactured by Honshu Chemical Industry Co., Ltd.) as a crosslinking agent, 0.01 g of pyridinium-4-hydroxybenzenesulfonate as a crosslinking catalyst, 0.001 g of a fluorine-based surfactant (product name: Megafac R-40, manufactured by DIC Corporation) as a surfactant, 14.58 g of propylene glycol monomethyl ether, and 1.92 g of propylene glycol monomethyl ether acetate.

[0141] [Resist Solvent Resistance Test] Each of the protective film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 1 to 8 was applied (spin coated) onto a silicon wafer using a spin coater. The coated silicon wafer was heated on a hot plate at 250°C for 1 minute to form a 100 nm thick coating (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, spin-dried, and then baked at 100°C for 30 seconds. The thickness of the protective film before and after immersion in the mixed solvent was measured using an optical interference film thickness meter (product name: Nanospec 6100, manufactured by Nanometrics Japan Co., Ltd.).

[0142] Resist solvent resistance was evaluated by calculating the film thickness reduction rate (%) of the protective film removed by solvent immersion using the formula ((film thickness before solvent immersion) - (film thickness after solvent immersion)) ÷ (film thickness before solvent immersion) × 100. The results are shown in Table 1. Note that a film thickness reduction rate of approximately 1% or less can be said to have sufficient resist solvent resistance.

[0143] [Table 1]

[0144] From the above results, the protective film-forming compositions of Examples 1 to 8 and Comparative Examples 1 to 8 showed very little change in film thickness even after immersion in a resist solvent. Therefore, the protective film-forming compositions of Examples 1 to 8 have sufficient resist solvent resistance to function as a protective film.

[0145] [Basic hydrogen peroxide resistance test] To evaluate resistance to basic hydrogen peroxide solution, each of the protective film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 1 to 8 was applied to a 50-nm-thick titanium nitride (TiN)-deposited substrate and heated at 250°C for 1 minute to form a protective film with a thickness of 100 nm. Next, 28% ammonia water, 33% hydrogen peroxide, and water were mixed in a weight ratio of 1:1:2 to prepare basic hydrogen peroxide solution. The TiN-deposited substrate coated with the protective film-forming composition was immersed in this basic hydrogen peroxide solution heated to 50°C, and the time from immediately after immersion until the protective film peeled from the substrate (peeling time) was measured. The results of the resistance test to basic hydrogen peroxide solution are shown in Table 2. It can be said that the longer the peeling time, the higher the resistance to a wet etching solution using basic hydrogen peroxide solution.

[0146] [Acid hydrogen peroxide resistance test] To evaluate the resistance to acidic hydrogen peroxide solution, each of the protective film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 1 to 8 was applied to a TiN-deposited substrate with a thickness of 50 nm, and heated at 250°C for 1 minute to form a protective film with a thickness of 100 nm. 33% hydrogen peroxide The above components were mixed in a 1:1 weight ratio to prepare an acidic hydrogen peroxide solution. A TiN-deposited substrate coated with the protective film-forming composition was immersed in this acidic hydrogen peroxide solution heated to 60°C, and the time from immediately after immersion until the protective film peeled off from the substrate (peeling time) was measured. The results of the resistance test to acidic hydrogen peroxide solution are shown in Table 2. It can be said that the longer the peeling time, the higher the resistance to a wet etching solution using acidic hydrogen peroxide solution.

[0147] [Table 2]

[0148] From the above results, when Example 1, which used a polymer having a structure containing at least one pair of adjacent hydroxyl groups at its terminals, was compared with Comparative Example 1, which did not use such a polymer, the protective film peeling time with basic hydrogen peroxide was longer in Example 1. Similarly, when Example 2 was compared with Comparative Example 2, Example 3 with Comparative Example 3, Example 4 with Comparative Example 4, Example 5 with Comparative Example 5, and Example 6 with Comparative Example 6, the protective film peeling time with basic hydrogen peroxide or acidic hydrogen peroxide was longer in each Example.

[0149] That is, the results of Examples 1 to 6 show that by selecting and employing a polymer having a structure containing at least one pair of two adjacent hydroxyl groups in the molecule at its terminal, better resistance to a wet etching solution using a basic hydrogen peroxide solution, an acidic hydrogen peroxide solution, or both can be obtained compared to Comparative Examples 1 to 6 in which such a polymer is not selected or employed.

[0150] Furthermore, it can be said that Examples 7 to 8 exhibit better resistance to wet etching solutions using basic hydrogen peroxide solution, acidic hydrogen peroxide solution, or both, than Comparative Examples 1 to 6. Therefore, Examples 1 to 8 exhibit better chemical solution resistance to basic hydrogen peroxide solution, acidic hydrogen peroxide solution, or both, than Comparative Examples 1 to 6, and are therefore useful as protective films against semiconductor wet etching solutions.

[0151] [Evaluation of etching selectivity] To evaluate the etching selectivity, each of the protective film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 7 and 8 was applied to a silicon wafer and heated at 250°C for 1 minute to form a protective film with a thickness of 100 nm. Next, the formed protective film and a semiconductor lithography resist underlayer film (product name: ARC (registered trademark) 29A, manufactured by Nissan Chemical Industries, Ltd.) were dry-etched with nitrogen gas using a dry etching apparatus (product name: RIE-10NR, manufactured by Samco Inc.) to measure the dry etching rate ratio (dry etching rate selectivity) of the protective film. The measurement results of the etching selectivity are shown in Table 3. It can be said that the higher the etching selectivity, the faster the dry etching rate.

[0152] [Planarization test on patterned substrate] To test the planarization on a patterned substrate, the protective film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 7 and 8 were applied to a silicon substrate having a 200-nm depth and a 50-nm-wide trench and a 5-nm-thick TiN film deposited thereon, followed by heating at 250°C for 1 minute. The protective film-forming compositions were prepared so that they would have a film thickness of 100 nm when heated at 250°C for 1 minute on the silicon wafer. After forming the protective film on the patterned substrate, the film thickness in a dense pattern area with a 100-nm pitch and in an open area without a pattern was observed using a scanning electron microscope (product name: S-4800, manufactured by Hitachi High-Technologies Corporation), and the difference in film thickness between the dense area and the open area (film thickness bias) was measured. The film thickness bias measurement results are shown in Table 3. It can be said that the smaller the film thickness bias, the smaller the film thickness difference between the dense area and the open area, resulting in a more highly flat coating on a patterned substrate.

[0153] [Table 3]

[0154] From the above results, it can be said that Examples 1 to 8 have higher dry etching selectivity and therefore faster dry etching rates than Comparative Examples 7 and 8. That is, Examples 1 to 8 are useful because they can shorten the dry etching time required to remove the protective film and therefore reduce damage to the underlying substrate.

[0155] Furthermore, it can be said that Examples 1 to 8 have a smaller film thickness difference (film thickness bias) between dense areas and open areas compared to Comparative Examples 7 and 8, and can form a film more evenly on a patterned base substrate. That is, Examples 1 to 8 are useful because they are less likely to cause non-uniformity in film thickness on a patterned base substrate and can uniformly remove a certain amount of protective film in a desired etching time.

[0156] That is, Examples 1 to 8 have better resistance to a semiconductor wet etching solution using a basic hydrogen peroxide solution, an acidic hydrogen peroxide solution, or both than Comparative Examples 1 to 6, have a faster etching rate than Comparative Examples 7 and 8, and can be applied evenly to a patterned base substrate. Thus, the present invention can provide a protective film-forming composition that has high wet etching solution resistance, a high etching rate, and high planarization properties. [Industrial Applicability]

[0157] The protective film-forming composition of the present invention has excellent resistance when a wet etching solution is applied to substrate processing and a high dry etching rate, making substrate processing easy, and provides a protective film that has excellent planarization properties when applied to a stepped substrate.

Claims

1. A protective film-forming composition for a semiconductor wet etching solution, comprising: a polymer having a structure containing at least one pair of adjacent hydroxyl groups in the molecule at its terminal; and an organic solvent, The polymer is 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】 The unit structure is represented by any one of the following: The structure containing at least one pair of adjacent hydroxyl groups in the molecule is represented by formula (1): 【Transformation 8】 (In formula (1), X represents —NH—, and R １ represents a hydrogen atom or a methyl group. Y represents a directly bonded or optionally substituted alkylene group having 1 to 4 carbon atoms. R ２ , R ３ and R ４ are each a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 40 carbon atoms, and R ２ is R ３ or R ４ may form a ring together with The compound (A) contains a 1,2-ethanediol structure represented by Protective film forming composition.

2. In the formula (1), R ２ , R ３ and R ４ The protective film-forming composition according to claim 1 , wherein is a hydrogen atom.

3. 3. The protective film-forming composition according to claim 1, wherein Y in formula (1) is a methylene group.

4. A protective film-forming composition described in any one of claims 1 to 3, further comprising a crosslinking catalyst.

5. A protective film-forming composition described in any one of claims 1 to 4, further comprising a crosslinking agent.

6. A protective film-forming composition described in any one of claims 1 to 5, further comprising a surfactant.

7. A protective film characterized by being a fired product of a coating film made of a protective film-forming composition described in any one of claims 1 to 6.

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