Protective film-forming composition containing a diol structure

Abstract

The present invention provides a composition for forming a protective film, which has a good masking (protecting) function against a wet etching liquid at the time of processing a semiconductor substrate, has a low etching speed, and further has a good covering property and embeddability for a step substrate, a small film thickness difference after embedding, and enables formation of a flat film. The present invention also provides a protective film, a resist underlayer film, a substrate with a resist pattern, and a manufacturing method of a semiconductor device, which are manufactured using the composition. A composition for forming a protective film against a wet etching liquid for a semiconductor, which contains a compound having a molecular weight of 1500 or less, and an organic solvent, the compound having a structure in which at least one set of two hydroxyl groups adjacent to each other is contained within a molecule, and the average particle diameter of particles present in the composition is 3 nm or less as measured by a dynamic light scattering method.

Description

Technical Field

[0001] This invention relates to a composition for forming a protective film with excellent resistance to wet etching solutions for semiconductors in the photolithography process of semiconductor manufacturing. It also relates to a method for manufacturing a substrate with a resist pattern on which the aforementioned protective film is applied, and a method for manufacturing a semiconductor device. Background Technology

[0002] In semiconductor manufacturing, photolithography is a known process for forming a resist pattern of desired shape by depositing a resist underlayer between a substrate and a resist film formed thereon. Substrate processing is performed after the resist pattern is formed, primarily using dry etching, but wet etching is sometimes used depending on the substrate type. Patent Document 1 discloses a composition for forming a protective film against wet etching solutions for semiconductors, comprising a compound or polymer thereof containing at least one set of two adjacent hydroxyl groups in its molecule, and a solvent. Patent Document 2 discloses a resist underlayer composition with excellent embedding properties, comprising a resin obtained by reacting an epoxy-containing resin with a compound having thiol groups.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] International Publication No. 2019 / 124474

[0006] [Patent Document 2] International Publication No. 2019 / 059210 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] When forming a protective film for a semiconductor substrate using a protective film forming composition, and using the protective film as an etching mask for wet etching of the substrate, the protective film must have good masking function for the wet etching solution for semiconductors (i.e., the masked portion can protect the substrate).

[0009] Furthermore, there is a requirement for a protective film forming composition that can form a flat film with good coverage on a substrate with a so-called high-low difference and a small difference in film thickness after embedding.

[0010] In the past, in order to demonstrate resistance to SC-1 (ammonia-hydrogen peroxide solution), which is a type of etching solution, a method of using low molecular weight compounds (such as gallic acid) as additives was used, but there are limitations to solving the above problems.

[0011] Furthermore, the protective film used for the above purposes is expected to function as a resist underlayer to solve problems such as poor shape formation when the resist pattern is formed.

[0012] The purpose of this invention is to solve the above-mentioned problems.

[0013] [Methods used to solve the above problems]

[0014] This invention includes the following.

[0015] [1]. A composition for forming a protective film against a wet etchant for semiconductors, comprising a non-heterocyclic compound (A) with a weight-average molecular weight of 1500 or less, an organic solvent, and particles with an average particle size of 3 nm or less as measured by dynamic light scattering.

[0016] The compound (A) has the following structure at its end: it contains at least one set of two adjacent hydroxyl groups within the molecule.

[0017] [2]. The composition for forming a protective film of the wet etchant for defending semiconductors as described in [1] has excellent embedding properties for narrow gaps on semiconductor substrates.

[0018] [3]. The protective film forming composition as described in [1] or [2], wherein the compound (A) comprises an aromatic hydrocarbon or an alicyclic hydrocarbon.

[0019] [4]. The protective film forming composition as described in any one of [1] to [3], wherein the compound (A) has a 1,2-ethylene glycol structure as a structure containing at least one set of two adjacent hydroxyl groups within the molecule.

[0020] [5]. A composition for forming a protective film with a wet etchant for defending semiconductors as described in any one of [1] to [4], wherein the compound (A) comprises the following partial structure:

[0021]

[0022] In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, and X 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 -, X 3 It represents a hydrogen atom or a methyl group.

[0023] [6]. The composition for forming a protective film with a wet etchant for defending semiconductors as described in [5], wherein X of the above formula (1) 1 X represents an ether bond. 2 This indicates a thioether bond.

[0024] [7]. The protective film forming composition as described in any one of [1] to [6] further comprises an acid catalyst.

[0025] [8]. A protective film, characterized in that it is a sintered product of a coated film formed by any one of the protective film forming compositions described in any one of [1] to [7].

[0026] [9]. A composition for forming a resist underlayer film comprises a non-heterocyclic compound (A) with a weight-average molecular weight of 1500 or less, an organic solvent, and particles with an average particle size of 3 nm or less as measured by dynamic light scattering.

[0027] The compound (A) has at its end a structure containing at least one set of two adjacent hydroxyl groups within the molecule.

[0028]

[10] . The composition for forming a resist underlayer as described in [9] has excellent embedding properties for narrow gaps on semiconductor substrates.

[0029]

[11] . A composition for forming a resist underlayer film as described in [9] or

[10] , wherein the compound (A) comprises an aromatic hydrocarbon or an alicyclic hydrocarbon.

[0030]

[12] . The composition for forming a resist underlayer film as described in any one of [9] to

[11] , wherein the compound (A) has a 1,2-ethylene glycol structure as a structure containing at least one set of two adjacent hydroxyl groups within the molecule.

[0031]

[13] . The composition for forming a resist underlayer film as described in any one of [9] to

[12] , wherein the compound (A) comprises the following partial structure:

[0032]

[0033] In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, and X 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 -, X 3 It represents a hydrogen atom or a methyl group.

[0034]

[14] . The composition for forming a resist underlayer film as described in

[13] , wherein X of the above formula (1) 1 X represents an ether bond. 2 This indicates a thioether bond.

[0035]

[15] . The composition for forming a resist underlayer film as described in any one of [9] to

[14] further comprises an acid catalyst and / or a crosslinking agent.

[0036]

[16] . A resist underlayer film, characterized in that it is a sintered product of a coating film formed by any one of the resist underlayer film forming compositions [9] to

[15] .

[0037]

[17] . A method for manufacturing a substrate with a protective film, characterized in that it is used to manufacture a semiconductor and includes the step of coating a protective film forming composition as described in any one of [1] to [7] onto a semiconductor substrate having a height difference and firing it to form a protective film.

[0038]

[18] . A method for manufacturing a substrate with a resist pattern, characterized in that it is used to manufacture semiconductors and comprises:

[0039] The step of coating a protective film forming composition or a resist underlayer film forming composition as described in any one of [1] to [7] or [9] to

[15] onto a semiconductor substrate and firing it to form a protective film as a resist underlayer film; and

[0040] A resist film is formed on the protective film, followed by exposure and development to form the resist pattern.

[0041]

[19] . A method for manufacturing a semiconductor device, comprising the following steps:

[0042] A protective film is formed on a semiconductor substrate on which an inorganic film can be formed on the surface using the protective film forming composition described in any one of [1] to [7].

[0043] A resist pattern is formed on the protective film.

[0044] Using the resist pattern as a mask, the protective film is dry-etched to expose the surface of the inorganic film or the semiconductor substrate.

[0045] Using the dry-etched protective film as a mask, the inorganic film or the semiconductor substrate is wet-etched using a semiconductor wet etching solution, and then cleaned.

[0046]

[20] . A method for manufacturing a semiconductor device, comprising the following steps:

[0047] A photoresist underlayer film is formed on a semiconductor substrate on which an inorganic film can be formed on the surface using any of the compositions described in [9] to

[15] for forming a photoresist underlayer film.

[0048] A resist pattern is formed on the lower resist film.

[0049] Using the resist pattern as a mask, the underlying resist film is dry-etched to expose the surface of the inorganic film or the semiconductor substrate.

[0050] The inorganic film or the semiconductor substrate is etched using the dry-etched resist underlayer as a mask.

[0051] [Invention Effects]

[0052] The protective film forming composition of the present invention is required to have, for example, the following characteristics in a balanced manner during photolithography in semiconductor manufacturing: (1) good masking function for wet etchant during substrate processing; (2) further reducing damage to the protective film or the underlayer of the resist during substrate processing by a low dry etching rate; (3) excellent planarization properties for substrates with high and low elevation differences; and (4) excellent embedding properties for substrates with micro-groove patterns. Because it has these properties (1) to (4) in a balanced manner, the micro-processing of semiconductor substrates can be easily performed. Attached Figure Description

[0053] Figure 1 This is a schematic cross-sectional view of the embedding performance evaluation substrate of the embodiment.

[0054] Figure 2 These are cross-sectional SEM images evaluating the embedding performance of the protective film forming compositions of Examples 1-8 on substrates with varying elevations. Detailed Implementation

[0055] <Composition for forming protective film>

[0056] The protective film forming composition of this application comprises: a heterocyclic compound (A) having at its terminal at least one set of two adjacent hydroxyl groups and a weight-average molecular weight of 1500 or less, and an organic solvent, and a wet etching solution for semiconductor protection. The composition is characterized in that the average particle size of the particles present in it, as measured by dynamic light scattering, is 3 nm or less. These particles are derived from the compound with a larger molecular weight, as described later.

[0057] The weight-average molecular weight described above can be determined, for example, by the gel permeation chromatography method described in the examples.

[0058] <Average particle size measured by dynamic light scattering>

[0059] The protective film forming composition of this application can be measured as particles by dynamic light scattering (DLS) when a compound (polymer) with a large molecular weight is present. Compared with polymers described in the prior art, the compound (A) of this application has a smaller molecular weight (1500 or less), resulting in an average particle size of 3 nm or less in DLS. More preferably, the average particle size is less than 3 nm, or 2 nm or less, or 1 nm or less. The average particle size figure on the left indicates the detection limit at the measurement point in the DLS measuring device. Due to the small average particle size, the aforementioned compound of this application exhibits excellent embedding properties for semiconductor substrates with height differences, such as fine trench patterned substrates.

[0060] The aforementioned compound (A) preferably contains aromatic hydrocarbons or alicyclic hydrocarbons.

[0061] The structure containing at least one set of two adjacent hydroxyl groups within the aforementioned molecule is preferably a 1,2-ethylene glycol structure.

[0062] The above-mentioned compounds preferably have the following partial structures.

[0063]

[0064] (In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, X) 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 - either of them, X 3 (Represents a hydrogen atom or a methyl group).

[0065] The above X is preferred 1 X represents an ether bond. 2 This indicates a thioether bond.

[0066] The term "can be substituted by the above-mentioned substituents" means that some or all of the hydrogen atoms present in the benzene ring, naphthalene ring or anthracene ring contained in Ar of this application can be substituted by, for example, hydroxyl, halogen atom, carboxyl, nitro, cyano, methylenedioxy, acetoxy, methylthio, amino or alkoxy with 1 to 9 carbon atoms.

[0067] Examples of alkoxy groups with 1 to 9 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, 1-methyl-n-butoxy, 2-methyl-n-butoxy, 3-methyl-n-butoxy, 1,1-dimethyl-n-propoxy, 1,2-dimethyl-n-propoxy, 2,2-dimethyl-n-propoxy, 1-ethyl-n-propoxy, n-hexyloxy, 1-methyl-n-pentoxy, 2-methyl-n-pentoxy, 3-methyl-n-pentoxy, 4-methyl - n-pentoxy, 1,1-dimethyl-n-butoxy, 1,2-dimethyl-n-butoxy, 1,3-dimethyl-n-butoxy, 2,2-dimethyl-n-butoxy, 2,3-dimethyl-n-butoxy, 3,3-dimethyl-n-butoxy, 1-ethyl-n-butoxy, 2-ethyl-n-butoxy, 1,1,2-trimethyl-n-propoxy, 1,2,2-trimethyl-n-propoxy, 1-ethyl-1-methyl-n-propoxy, 1-ethyl-2-methyl-n-propoxy, n-heptoxy, n-octoxy, and n-nonoxy, etc.

[0068] <A compound (A) that is heterocyclic and has at least one set of two adjacent hydroxyl groups at the end of the molecule and has a molecular weight of less than 1500>

[0069] The compound (A) of this application is not particularly limited if it is a heterocyclic compound having at least one set of two adjacent hydroxyl groups at the end of the molecule and having a molecular weight of less than 1500, but preferably includes a portion of the structure of formula (1). Specific examples of compounds containing a portion of the structure of compound formula (1) are preferably reaction products obtained by reacting a compound represented by formulas (a-1) to (a-43) (i.e., a compound having 2 to 4 epoxy groups linked by ester bonds, ether bonds, alkylene groups of 1 to 10 carbon atoms and / or nitrogen atoms in one molecule and containing an aromatic hydrocarbon or alicyclic hydrocarbon in which hydrogen atoms can be replaced by alkyl groups of 1 to 10 carbon atoms, alkenyl groups of 3 to 6 carbon atoms and / or ketyl groups, wherein the epoxy group can be a glycidyl ether group) with a compound represented by formulas (b-1) to (b-4) (i.e., a compound having an organic group such as a thiol group, amino group, methylamino group and / or carboxyl group in one molecule that can react with an epoxy group and having a 1,2-ethylene glycol structure at its end) by a known method.

[0070]

[0071] Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl- Cyclobutyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl - n-Butyl, 2-Ethyl-n-Butyl, 1,1,2-Trimethyl-n-Propyl, 1,2,2-Trimethyl-n-Propyl, 1-Ethyl-1-Methyl-n-Propyl, 1-Ethyl-2-Methyl-n-Propyl, Cyclohexyl, 1-Methyl-Cyclopentyl, 2-Methyl-Cyclopentyl, 3-Methyl-Cyclopentyl, 1-Ethyl-Cyclobutyl, 2-Ethyl-Cyclobutyl, 3-Ethyl-Cyclobutyl, 1,2-Dimethyl-Cyclobutyl, 1,3-Dimethyl-Cyclobutyl, 2,2-Dimethyl-Cyclobutyl, 2,3-Dimethyl-Cyclobutyl 1-Cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropyl, 2-isopropyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl, 2-ethyl-3-methyl-cyclopropyl, decyl.

[0072] Examples of alkylene groups having 1 to 10 carbon atoms include methylene, ethylene, n-propylene, isopropylene, cyclopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, cyclobutylene, 1-methyl-cyclopropylene, 2-methyl-cyclopropylene, n-pentylene, 1-methyl-n-butylene, 2-methyl-n-butylene, 3-methyl-n-butylene, 1,1-dimethyl-n-propylene, 1,2-dimethyl-n-propylene, 2,2-dimethyl-n-propylene, 1-ethyl-n-propylene, cyclopentylene, 1-methyl-cyclobutylene, 2-methyl - Cyclobutylene, 3-methyl-cyclobutylene, 1,2-dimethyl-cyclopropylene, 2,3-dimethyl-cyclopropylene, 1-ethyl-cyclopropylene, 2-ethyl-cyclopropylene, n-hexylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-pentylene, 4-methyl-n-pentylene, 1,1-dimethyl-n-butylene, 1,2-dimethyl-n-butylene, 1,3-dimethyl-n-butylene, 2,2-dimethyl-n-butylene, 2,3-dimethyl-n-butylene, 3,3-dimethyl-n-butylene, 1-ethyl-n-butylene Butyl, 2-ethyl-n-butylene, 1,1,2-trimethyl-n-propylene, 1,2,2-trimethyl-n-propylene, 1-ethyl-1-methyl-n-propylene, 1-ethyl-2-methyl-n-propylene, cyclohexylene, 1-methyl-cyclopentylene, 2-methyl-cyclopentylene, 3-methyl-cyclopentylene, 1-ethyl-cyclobutylene, 2-ethyl-cyclobutylene, 3-ethyl-cyclobutylene, 1,2-dimethyl-cyclobutylene, 1,3-dimethyl-cyclobutylene, 2,2-dimethyl-cyclobutylene, 2,3-dimethyl-cyclobutylene, 2, 4-Dimethyl-cyclobutylene, 3,3-Dimethyl-cyclobutylene, 1-n-propyl-cyclopropylene, 2-n-propyl-cyclopropylene, 1-isopropyl-cyclopropylene, 2-isopropyl-cyclopropylene, 1,2,2-trimethyl-cyclopropylene, 1,2,3-trimethyl-cyclopropylene, 2,2,3-trimethyl-cyclopropylene, 1-ethyl-2-methyl-cyclopropylene, 2-ethyl-1-methyl-cyclopropylene, 2-ethyl-2-methyl-cyclopropylene, 2-ethyl-3-methyl-cyclopropylene, n-heptylene, n-octylene, n-nonylene, or n-decylene.

[0073] Examples of alkenyl groups with 3 to 6 carbon atoms include 1-propenyl, 2-propenyl, 1-methyl-1-vinyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylvinyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethyl-2-propenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, and 2-methyl-3-butenyl. 3-Methyl-1-butenyl, 3-methyl-2-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1-isopropylvinyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-cyclopentenyl, 2-cyclopentenyl, 3-cyclopentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 1-methyl-2-pentenyl, 1-methyl-3-pentenyl, 1-methyl-4-pentenyl, 1-n-butylvinyl, 2-methyl-1-pentenyl, 2-methyl-2-pentenyl, 2-methyl-3-pentenyl 2-Methyl-4-pentenyl, 2-n-propyl-2-propenyl, 3-methyl-1-pentenyl, 3-methyl-2-pentenyl, 3-methyl-3-pentenyl, 3-methyl-4-pentenyl, 3-ethyl-3-butenyl, 4-methyl-1-pentenyl, 4-methyl-2-pentenyl, 4-methyl-3-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl, 1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1-methyl-2-ethyl-2-propenyl, 1-sec-butylvinyl, 1,3-di Methyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 1-isobutylvinyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 2-isopropyl-2-propenyl, 3,3-dimethyl-1-butenyl, 1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 1-n-propyl-1-propenyl, 1-n-propyl-2-propenyl, 2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-Trimethyl-2-propenyl, 1-tert-butylvinyl, 1-Methyl-1-ethyl-2-propenyl, 1-Ethyl-2-methyl-1-propenyl, 1-Ethyl-2-methyl-2-propenyl, 1-Isopropyl-1-propenyl, 1-Isopropyl-2-propenyl, 1-Methyl-2-cyclopentenyl, 1-Methyl-3-cyclopentenyl, 2-Methyl-1-cyclopentenyl, 2-Methyl-2-cyclopentene The list includes 2-methyl-3-cyclopentenyl, 2-methyl-4-cyclopentenyl, 2-methyl-5-cyclopentenyl, 2-methylene-cyclopentenyl, 3-methyl-1-cyclopentenyl, 3-methyl-2-cyclopentenyl, 3-methyl-3-cyclopentenyl, 3-methyl-4-cyclopentenyl, 3-methyl-5-cyclopentenyl, 3-methylene-cyclopentenyl, 1-cyclohexenyl, 2-cyclohexenyl, and 3-cyclohexenyl, among others.

[0074] Of the compounds represented by formulas (b-1) to (b-4) above, (b-4) is particularly preferred.

[0075] The weight-average molecular weight of the compound containing a portion of the structure of formula (1) is preferably 1500 or less, 1400 or less, 1200 or less, 1000 or less, 900 or less, 800 or less, 700 or less, or 600 or less.

[0076] <Organic Solvents>

[0077] The protective film forming composition of the present invention can be prepared by dissolving the above-mentioned components in an organic solvent and used in a homogeneous solution state.

[0078] As for the organic solvent used in the protective film forming composition of the present invention, any organic solvent capable of dissolving the above-mentioned compound and the solid components such as the acid catalyst described below can be used without particular limitation. In particular, since the protective film forming composition of the present invention is used in a homogeneous solution state, it is recommended to use it in conjunction with organic solvents generally used in the photolithography step, considering its coating performance.

[0079] Examples of organic solvents mentioned above include, for example, 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, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate. Ethyl 2-hydroxyisobutyrate, ethyl ethoxylate, 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.

[0080] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred. Propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are particularly preferred.

[0081] The protective film forming composition of this application may further contain an acid catalyst.

[0082] In addition to acidic and basic compounds, compounds that can generate acids or bases through heat can also be used as acid catalysts. Sulfonic acid compounds or carboxylic acid compounds can be used as acidic compounds, and thermally generated acid agents can be used as compounds that generate acids through heat.

[0083] Examples of sulfonic acid or carboxylic acid compounds include, for example, p-toluenesulfonic acid, trifluoromethanesulfonic acid, and pyridine. Trifluoromethanesulfonate (=pyridine) Trifluoromethanesulfonic acid), pyridine - p-Toluenesulfonate, pyridine 4-Hydroxybenzenesulfonate, salicylic acid, camphor sulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, pyridine -4-hydroxybenzenesulfonate, benzene disulfonic acid, 1-naphthalenesulfonic acid, 4-nitrobenzenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, etc.

[0084] Examples of heat-generating acid agents include K-PURE [registered trademark] CXC-1612, K-PURE CXC-1614, K-PURE TAG-2172, K-PURE TAG-2179, K-PURE TAG-2678, K-PURE TAG2689 (all manufactured by King Industries) and SI-45, SI-60, SI-80, SI-100, SI-110, SI-150 (all manufactured by Sanshin Chemical Industry Co., Ltd.).

[0085] These acid catalysts can be used in one or in combination of two or more. As a base compound, amine compounds or ammonium hydroxide compounds can be used, and as a compound that generates a base through heat, urea can be used.

[0086] Examples of amine compounds include tertiary amines such as triethanolamine, tributanolamine, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, tri-tert-butylamine, tri-n-octylamine, triisopropanolamine, phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, as well as aromatic amines such as pyridine and 4-dimethylaminopyridine. Furthermore, examples of primary amines such as benzylamine and n-butylamine, and secondary amines such as diethylamine and di-n-butylamine, are also included. These amine compounds can be used alone or in combination of two or more.

[0087] Examples of ammonium hydroxide compounds include, for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, cetyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, and phenyltriethylammonium hydroxide.

[0088] Furthermore, as compounds that generate a base by heat, compounds having thermally unstable groups such as amide, carbamate, or aziridinium groups, and that generate an amine by heating, can be used. Examples of compounds that generate a base by heat include urea, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylphenylammonium chloride, benzyldodecyldimethylammonium chloride, benzyltributylammonium chloride, and choline chloride.

[0089] When the protective film forming composition of this application contains an acid catalyst, its content relative to the total solid content of the protective film forming composition is 0.0001 to 20% by mass, preferably 0.01 to 15% by mass, and more preferably 0.1 to 10% by mass.

[0090] The solid content of the protective film forming composition of the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solid content refers to the percentage of all components contained in the protective film forming composition after removing the solvent. The polymer percentages in the solid content are 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.

[0091] <Composition for forming a lower layer film of resist>

[0092] The composition for forming a resist underlayer film of this application is characterized by comprising: a heterocyclic compound having at least one set of two adjacent hydroxyl groups at the end of the molecule and having a weight-average molecular weight of 1500 or less, and an organic solvent, wherein the average particle size of the particles present in the composition is 3 nm or less by dynamic light scattering.

[0093] Weight-average molecular weight determination and average particle size determination by dynamic light scattering method are as described above.

[0094] The aforementioned compounds preferably contain aromatic hydrocarbons or alicyclic hydrocarbons.

[0095] The structure containing at least one set of two adjacent hydroxyl groups within the aforementioned molecule is preferably a 1,2-ethylene glycol structure.

[0096] The aforementioned compounds preferably contain the following partial structures.

[0097]

[0098] (In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, X) 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 - either of them, X 3 (Represents a hydrogen atom or a methyl group).

[0099] The above X is preferred 1 X represents an ether bond. 2 This indicates a thioether bond.

[0100] The acid catalyst, its content, and the organic solvent are the same as those in the above-mentioned composition for forming a protective film.

[0101] The solid content of the resist lower film forming composition of the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solid content refers to the proportion of all components in the protective film forming composition after removing the solvent. The polymer proportions in the solid content are 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.

[0102] <Cross-linking agent>

[0103] The resist underlayer film forming composition of the present invention may include a crosslinking agent. Examples of crosslinking agents include melamine-based, substituted urea-based, or polymeric systems thereof. Preferably, the crosslinking agent has at least two crosslinking-forming substituents and may be a compound of methoxymethylated glycourea, butoxymethylated glycourea, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensates of these compounds may also be used.

[0104] Furthermore, crosslinking agents with high heat resistance can be used as the aforementioned crosslinking agents. Compounds containing crosslinking-forming substituents with aromatic rings (e.g., benzene rings, naphthalene rings) within their molecules can also be used as high heat-resistant crosslinking agents.

[0105] Examples of these compounds include compounds having a partial structure of the following formula (5-1), or polymers or oligomers having repeating units of the following formula (5-2).

[0106]

[0107] The above R 11 R 12 R 13 and R 14 It is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and specific examples of these alkyl groups are given above.

[0108] m1 is 1≤m1≤6-m2, m2 is 1≤m2≤5, m3 is 1≤m3≤4-m2, and m4 is 1≤m4≤3.

[0109] Examples of compounds, polymers, and oligomers of formulas (5-1) and (5-2) are shown below.

[0110]

[0111] The above-mentioned compounds can be obtained as products of Asahi Organic Materials Co., Ltd. and Honshu Chemical Co., Ltd. For example, the compound of formula (6-22) in the above-mentioned crosslinking agent can be obtained under the trade name TMOM-BP of Asahi Organic Materials Co., Ltd.

[0112] The amount of crosslinking agent added varies depending on the coating solvent used, the substrate used, the required solution viscosity, the required film shape, etc., but is generally 0.001 to 80% by mass relative to the total solid content of the protective film forming composition, preferably 0.01 to 50% by mass, and more preferably 0.1 to 40% by mass. Although these crosslinking agents may sometimes cause crosslinking reactions due to self-condensation, when crosslinking substituents are present in the polymers of the present invention, crosslinking reactions with these crosslinking substituents can occur.

[0113] <Manufacturing Method of Protective Film, Underlayer Resist Film, Substrate with Resist Pattern, and Semiconductor Device>

[0114] Hereinafter, a method for manufacturing a substrate with a resist pattern using the protective film forming composition (resist underlayer film forming composition) of the present invention and a method for manufacturing a semiconductor device will be described.

[0115] The substrate with resist pattern of the present invention can be prepared by coating the above-mentioned protective film forming composition (resist underlayer film forming composition) onto a semiconductor substrate and firing it.

[0116] Examples of semiconductor substrates for coating the protective film forming composition (resist underlayer film forming composition) of the present invention include, for example, silicon wafers, germanium wafers, and compound semiconductor wafers of gallium arsenide, indium phosphide, gallium nitride, indium nitride, aluminum nitride, etc.

[0117] When used in semiconductor substrates with inorganic films formed on their surfaces, these inorganic films are formed using methods such as ALD (Atomic Layer Deposition), CVD (Chemical Vapor Deposition), reactive sputtering, ion plating, vacuum evaporation, and spin coating (SOG). Examples of such inorganic films include polycrystalline silicon films, silicon oxide films, silicon nitride films, silicon oxynitride films, BPSG (borosilicate glass phosphate) films, titanium nitride films, titanium oxynitride films, tungsten nitride films, gallium nitride films, and gallium arsenide films. The semiconductor substrates described above can also be substrates with varying elevations, such as vias and trenches. For example, when viewed from above, the vias are approximately circular in shape, with a diameter of approximately 1 nm to 20 nm and a depth of 50 nm to 500 nm. The trenches, for example, have a width of 2 nm to 20 nm and a depth of 50 nm to 500 nm. The protective film forming composition (resist underlayer film forming composition) of this application has a small weight-average molecular weight and average particle size of the compounds contained in the composition, so that the composition can be embedded in the aforementioned substrates with varying elevations without defects such as pores (voids). The absence of defects such as pores is an important characteristic for the next step in semiconductor manufacturing (wet etching / dry etching of semiconductor substrates, resist patterning).

[0118] The protective film forming composition (resist underlayer film forming composition) of the present invention is applied to these semiconductor substrates using a coating method such as a spinner or coater. Subsequently, a protective film (resist underlayer film) is formed by baking using a heating means such as a heating plate. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 minutes to 60 minutes. Preferably, the baking temperature is 120°C to 350°C and the baking time is 0.5 minutes to 30 minutes; more preferably, the baking temperature is 150°C to 300°C and the baking time is 0.8 minutes 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. When the baking temperature is below the above range, cross-linking is insufficient, and the formed protective film (resist underlayer film forming composition) is difficult to obtain resistance to resist solvents or alkaline hydrogen peroxide aqueous solutions. On the other hand, if the baking temperature is higher than the above range, the protective film (the lower layer of the resist film) is at risk of decomposition due to heat.

[0119] Exposure is performed through a mask (reticle) used to form a specific pattern, using methods such as i-rays, KrF excimer lasers, ArF excimer lasers, EUV (extreme ultraviolet) or EB (electron beam). Development uses an alkaline developer, with a development temperature appropriately selected from 5°C to 50°C and a development time from 10 seconds to 300 seconds. As an alkaline developer, aqueous solutions of bases such as inorganic bases (e.g., sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia), primary amines (e.g., ethylamine, n-propylamine), secondary amines (e.g., diethylamine, di-n-butylamine), tertiary amines (e.g., triethylamine, methyldiethylamine), alkanolamines (e.g., dimethylethanolamine, triethanolamine), quaternary ammonium salts (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline), and cyclic amines (e.g., pyrrole, piperidine) can also be used. Alternatively, an appropriate amount of an alcohol such as isopropanol or a nonionic surfactant can be added to the above-mentioned alkaline aqueous solutions. Preferred developers among these are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants may be added to these developers. Alternatively, instead of alkaline developers, organic solvents such as butyl acetate may be used for development, thereby developing the portion of the photoresist whose alkaline dissolution rate has not been increased.

[0120] Next, using the formed resist pattern as a mask, the aforementioned protective film (the composition for forming the resist underlayer film) is dry-etched. At this time, when the aforementioned inorganic film is formed on the surface of the semiconductor substrate, the surface of the inorganic film is exposed; when the aforementioned inorganic film is not formed on the surface of the semiconductor substrate, the surface of the semiconductor substrate is exposed.

[0121] Furthermore, using the dry-etched protective film (a composition for forming a resist underlayer film) (which also represents the resist pattern if a resist pattern remains on the protective film / resist underlayer film) as a mask, the desired pattern is formed by wet etching with a semiconductor wet etchant.

[0122] As a wet etching solution for semiconductors, it can be any general solution used for etching semiconductor wafers, such as acidic or alkaline substances.

[0123] Examples of substances that exhibit acidity include, for example, hydrogen peroxide, hydrofluoric acid, ammonium fluoride, acidic ammonium fluoride, ammonium hydrofluoride, buffered hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, or mixtures thereof.

[0124] Examples of substances exhibiting alkalinity include ammonia, sodium hydroxide, potassium hydroxide, sodium cyanide, potassium cyanide, and alkaline hydrogen peroxide solution (made by mixing organic amines such as triethanolamine with hydrogen peroxide water to achieve an alkaline pH). A specific example is SC-1 (ammonia-hydrogen peroxide solution). Furthermore, solutions that can achieve an alkaline pH, such as mixing urea with hydrogen peroxide water and heating it to cause the thermal decomposition of urea to produce ammonia, can also be used as wet etching solutions.

[0125] Among these, acidic hydrogen peroxide water or alkaline hydrogen peroxide water is preferred.

[0126] These solutions may also contain additives such as surfactants.

[0127] The desired operating temperature for the semiconductor wet etching solution is 25°C to 90°C, and more preferably 40°C to 80°C. The desired wet etching time is 0.5 minutes to 30 minutes, and more preferably 1 minute to 20 minutes.

[0128] [Example]

[0129] The following examples illustrate the content of the present invention, but the present invention is not limited thereto.

[0130] The weight-average molecular weights of the compounds shown in the following synthetic examples in this specification were determined by gel permeation chromatography (hereinafter referred to as GPC). The determination was performed using a GPC apparatus manufactured by TOSOH Co., Ltd., under the following conditions.

[0131] GPC tubing: Shodex [registered trademark] (Showa Denko Co., Ltd.)

[0132] Column temperature: 40℃

[0133] Solvent: Tetrahydrofuran (THF)

[0134] Flow rate: 1.0 ml / min

[0135] Standard sample: Polystyrene (manufactured by TOSOH Corporation)

[0136] <Synthesis example 1>

[0137] 8.00 g of 1,1-bis(2,7-diglycidoxy-1-naphthyl)methane (manufactured by DIC Corporation, product name EPICLON HP-4700) and thioglycerol ( (Manufactured by (Company)) 8.00g and tetrabutyl bromide as a catalyst 0.63 g of (Beikō Chemical Co., Ltd.) was dissolved in 78.44 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-1). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 546 converted to standard polystyrene.

[0138]

[0139] <Synthesis example 2>

[0140] 11.00 g of 1,1'-methylene (2-glycidoxynaphthalene) (manufactured by DIC Corporation, product name EPICLON HP-4770) and thioglycerol ( (Manufactured by (Company)) 6.12g and tetrabutyl bromide as a catalyst 0.69 g of (Beikō Chemical Co., Ltd.) was dissolved in 71.23 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-2). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 552 converted to standard polystyrene.

[0141]

[0142] <Synthesis Example 3>

[0143] 6.00g of tetrahydroxyphenyl ethane tetraglycidyl ether (manufactured by Nippon Kayaku Co., Ltd., product name 1301S) and thioglycerin ( (Manufactured by (Company)) 4.84g and tetrabutyl bromide as a catalyst 0.37 g of (Beikō Chemical Co., Ltd.) was dissolved in 44.81 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-3). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 1385 converted to standard polystyrene.

[0144]

[0145] <Synthesis example 4>

[0146] 6.00g of 2-[4-(2,3-epoxypropoxy)phenyl]-2-(4-[1,1-bis[4-([2,3-epoxypropoxy]phenyl)ethyl]phenyl]propane (manufactured by Mitsubishi Chemical Co., Ltd., product name NC-6000) and thioglycerol ( (Manufactured by (Company)) 4.84g and tetrabutyl bromide as a catalyst 0.37 g of (Beikō Chemical Co., Ltd.) was dissolved in 44.81 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-4). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 950, converted to standard polystyrene.

[0147]

[0148] <Synthesis example 5>

[0149] 12.13g of commercially available epoxy resin (manufactured by DIC Corporation, product name EPICLON HP-6000) and thioglycerin ( (Manufactured by (Company)) 1.73g and tetrabutyl bromide as a catalyst 0.19 g of (Beikō Chemical Co., Ltd.) was dissolved in 56.20 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-5). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 613 converted to standard polystyrene.

[0150]

[0151] <Synthesis Example 6>

[0152] 9.97g of 1,3-diglycidoxybenzene (manufactured by NAGASECHEMTEX Co., Ltd., product name EX-201) and thioglycerol ( (Manufactured by (Company)) 10.01g and tetrabutyl bromide as a catalyst 1.12 g of (Beikō Chemical Co., Ltd.) was dissolved in 84.41 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-6). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 482 converted to standard polystyrene.

[0153]

[0154] <Synthesis Example 7>

[0155] 9.51g of 1,6-naphthalenediol glycidyl ether (manufactured by DIC Corporation, product name EPICRON (registered trademark) HP-4032D) and thioglycerin ( (Manufactured by (Company)) 7.36g and tetrabutyl bromide as a catalyst 0.82 g of (Beikō Chemical Co., Ltd.) was dissolved in 84.64 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-7). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 456 converted to standard polystyrene.

[0156]

[0157] <Synthesis example 8>

[0158] Hydroquinone-type crystalline epoxy resin ( Prepared, product name YDC-1312) 10.00g, thioglycerin ( (Manufactured by (Company)) 6.45g and tetrabutyl bromide as a catalyst 0.72 g of (Beikō Chemical Co., Ltd.) was dissolved in 68.70 g of propylene glycol monomethyl ether and reacted at 110 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is represented by formula (D-8). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 588 converted to standard polystyrene.

[0159]

[0160] <Synthesis Example 9>

[0161] 59.80 g of 1,3-diglycidoxybenzene (manufactured by NAGASECHEMTEX Co., Ltd., product name EX-201), 14.00 g of succinic acid (Tokyo Chemical Industry Co., Ltd.), and thioglycerol ( (Manufactured by (Company)) 2.85g and tetrabutyl bromide as a catalyst 3.35 g of (Beikō Chemical Co., Ltd.) was dissolved in 320.00 g of propylene glycol monomethyl ether and reacted at 100 °C for 24 hours to obtain a solution containing the reaction product (solid content 20% by mass). The resulting reaction product is expressed as formula (D-9). GPC analysis of the resulting reaction product yielded a weight-average molecular weight of 4772, converted to standard polystyrene.

[0162] <Example 1>

[0163] Pyridine was added to 3.20 g of the solution containing the reaction product obtained in Synthesis Example 1. A solution was prepared by mixing 0.0036 g of trifluoromethanesulfonic acid, 0.96 g of propylene glycol monomethyl ether acetate, and 5.83 g of propylene glycol monomethyl ether. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0164] <Example 2>

[0165] Pyridine was added to 2.28 g of the solution containing the reaction product obtained in Synthesis Example 2. A solution was prepared by mixing 0.0036 g of trifluoromethanesulfonic acid, 0.96 g of propylene glycol monomethyl ether acetate, and 6.75 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm, thereby preparing a composition for forming a protective film.

[0166] <Example 3>

[0167] Pyridine was added to 4.97 g of the solution containing the reaction product obtained in Synthesis Example 3. A solution was prepared by mixing 0.0053 g of trifluoromethanesulfonic acid, 1.45 g of propylene glycol monomethyl ether acetate, and 8.58 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0168] <Example 4>

[0169] Pyridine was added to 2.61 g of the solution containing the reaction product obtained in Synthesis Example 4. A solution was prepared by mixing 0.0036 g of trifluoromethanesulfonic acid, 0.96 g of propylene glycol monomethyl ether acetate, and 6.42 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm, thereby preparing a composition for forming a protective film.

[0170] <Example 5>

[0171] Pyridine was added to 2.39 g of the solution containing the reaction product obtained in Synthesis Example 5. A solution was prepared by mixing 0.0036 g of trifluoromethanesulfonic acid, 0.96 g of propylene glycol monomethyl ether acetate, and 6.65 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm, thereby preparing a composition for forming a protective film.

[0172] <Example 6>

[0173] Pyridine was added to 3.63 g of the solution containing the reaction product obtained in Synthesis Example 6. A solution was prepared by mixing 0.0041 g of trifluoromethanesulfonic acid, 1.11 g of propylene glycol monomethyl ether acetate, and 6.76 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0174] <Example 7>

[0175] Pyridine was added to 3.46 g of the solution containing the reaction product obtained in Synthesis Example 7. A solution was prepared by mixing 0.0041 g of trifluoromethanesulfonic acid, 1.11 g of propylene glycol monomethyl ether acetate, and 6.93 g of propylene glycol monomethyl ether. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0176] <Example 8>

[0177] Pyridine was added to 3.46 g of the solution containing the reaction product obtained in Synthesis Example 8. A solution was prepared by mixing 0.0041 g of trifluoromethanesulfonic acid, 1.11 g of propylene glycol monomethyl ether acetate, and 6.93 g of propylene glycol monomethyl ether. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0178] <Comparative Example 1>

[0179] Pyridine was added to 59.65 g of the solution containing the reaction product obtained in Synthesis Example 9. A solution was prepared by mixing 0.48 g of trifluoromethanesulfonic acid, 24.00 g of propylene glycol monomethyl ether acetate, and 165.86 g of propylene glycol monomethyl ether. This solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0180] <Coating Formation>

[0181] On a silicon substrate with a titanium nitride film formed on its surface, protective film forming compositions prepared in Examples 1 to 8 and protective film forming compositions prepared in Comparative Example 1 were coated by spin coating and baked at 250°C for 60 seconds to produce a coating film with a thickness of 100 nm.

[0182] <Determination of average particle size by dynamic light scattering (DLS)>

[0183] For the protective film forming compositions prepared in Examples 1 to 8 and the protective film forming compositions prepared in Comparative Example 1, a particle size measuring device using dynamic light scattering (DLS) was used. (Company) manufactures the nanoSA QLA multi-sample nanoparticle size determination system (detection limit: below 3 nm), which measures the average particle size of compositions used for protective film formation.

[0184]

[0185] The results in the table above show that the protective film forming compositions prepared in Examples 1 to 8 have smaller particle sizes compared to the protective film forming composition prepared in Comparative Example 1 (varnish).

[0186] <Evaluation of the embedding performance of the substrate>

[0187] Depend on Figure 1 As shown in the schematic diagram, on a silicon substrate with approximately 20 nm of silicon oxide film deposited by CVD on a silicon substrate having 50 nm trenches (L(line) / S(space)), a silicon processing substrate with a silicon oxide film formed on the surface of the trenches (after silicon oxide film deposition: 10 nm trenches (L(line) / S(space))) is prepared by spin coater. The substrate is then baked at 250°C for 60 seconds to produce a 100 nm thick coating. A cross-sectional SEM (S-4800) is used. (Company) confirmed the embedding properties.

[0188] The cross-sectional SEM observation results are shown below. Figure 2 In the protective film forming composition of the embodiment, for a substrate with 10nm trenches (L(line) / S(space)) where the gaps between silicon oxide films appear white in SEM images, the composition embeds the substrate without creating pores (voids, etc.) (the black areas in SEM images). Based on this embedding performance evaluation result, it can be predicted that since the compounds contained in the composition of this application are 3nm or less in size, the embedding performance is better than that of the protective film forming composition of the comparative example for substrates, for example, with micro-trenches having a linewidth of 3nm or less.

[0189] <Tolerance test to alkaline hydrogen peroxide aqueous solution>

[0190] Using the protective film forming compositions prepared in Examples 1 to 8 and the protective film forming composition prepared in Comparative Example 1, coatings were prepared on a silicon substrate with a titanium nitride film formed on its surface. These coatings were immersed in an alkaline hydrogen peroxide aqueous solution with the compositions shown in Table 2 below at the temperatures indicated in the table for 4 minutes, followed by rinsing with water. The state of the coating after drying was then visually observed. The results are shown in Table 3 below. In Table 3, "○" indicates that no peeling was observed after the 4-minute treatment, and "×" indicates that partial or complete peeling of the coating was observed after the 4-minute treatment.

[0191]

[0192] The results in the table above show that the coatings prepared using the protective film forming compositions formulated in Examples 1 to 8 have sufficient resistance to alkaline hydrogen peroxide aqueous solutions. This indicates that these coatings can serve as protective films against alkaline hydrogen peroxide aqueous solutions. On the other hand, it is clear that the coatings prepared using the film forming composition formulated in Comparative Example 1 are insufficient as protective films against alkaline hydrogen peroxide aqueous solutions.

[0193] <Experimentation of Optical Parameters>

[0194] The protective film forming compositions (resist underlayer film forming compositions) prepared in Examples 1-8 and Comparative Example 1 as described in this specification were respectively coated onto silicon wafers using a spin coater. The wafers were baked at 250°C for 1 minute on a hot plate to form a resist underlayer film (film thickness 50 nm). Then, for these protective film forming compositions, the n-values ​​(refractive index) and k-values ​​(attenuation coefficient or absorption coefficient) at wavelengths of 193 nm and 248 nm were measured using a spectroscopic ellipsometry (JAWoollam, VUV-VASE VU-302). The results are shown in Table 4.

[0195] <Determination of Dry Etching Rate>

[0196] The protective film forming compositions (resist underlayer film forming compositions) prepared in Examples 1-8 and Comparative Example 1 as described in this specification were each applied to a silicon wafer using a spin coater. The wafers were then baked at 250°C for 1 minute on a heated plate to form a resist underlayer film. The dry etching rate (the amount of film thickness reduction per unit time) was then measured using a dry etching apparatus (RIE-10NR) manufactured by Samco Corporation, with CF4 as the dry etching gas.

[0197] The dry etching rates of the protective film forming compositions prepared in Examples 1 to 8 as described in this specification were compared with the dry etching rate of Comparative Example 1. In Table 4, the dry etching rates of the protective film forming compositions of each embodiment when the dry etching rate of Comparative Example 1 was set to 1.00 are expressed as selection ratios.

[0198]

[0199] As can be seen from the above results, when comparing the dry etching rate of the protective film forming compositions prepared in Examples 1 to 8 as described in this specification with the dry etching rate of Comparative Example 1, the protective film forming compositions of Examples 1 to 8 were found to be slower.

[0200] Industry availability

[0201] The protective film forming composition of the present invention exhibits excellent resistance to wet etching solutions during substrate processing and has a low dry etching rate, thus providing a protective film with minimal damage during substrate processing. The resist underlayer film forming composition of the present invention also exhibits excellent resistance to wet etching solutions during substrate processing and has a low dry etching rate.

Claims

1. A composition for forming a protective film against a wet etchant for semiconductors, comprising a non-heterocyclic compound (A) with a weight-average molecular weight of 1500 or less, an organic solvent, and particles with an average particle size of 3 nm or less as measured by dynamic light scattering. The compound (A) is a reaction product obtained by reacting a compound having 2 to 4 epoxy groups linked by ester bonds, ether bonds, alkylene groups with 1 to 10 carbon atoms and / or nitrogen atoms, and containing hydrogen atoms that can be replaced by alkyl groups with 1 to 10 carbon atoms, alkenyl groups with 3 to 6 carbon atoms and / or ketyl groups, with an organic group that can react with epoxy groups and whose terminal part has a 1,2-ethylene glycol structure.

2. The composition for forming a protective film for a wet etchant for semiconductors as described in claim 1 has excellent embedding properties for narrow gaps on a semiconductor substrate.

3. The composition for forming a protective film with a wet etchant for semiconductors as described in claim 1, wherein compound (A) comprises the following partial structure: In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, and X 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 -, X 3 It represents a hydrogen atom or a methyl group.

4. The composition for forming a protective film with a wet etchant for defending semiconductors as described in claim 3, wherein X in formula (1) above... 1 X represents an ether bond. 2 This indicates a thioether bond.

5. The protective film forming composition of claim 1, further comprising an acid catalyst.

6. A protective film, characterized in that, It is a fired product of a coating film formed by the composition for forming a protective film according to any one of claims 1 to 5.

7. A composition for forming a resist underlayer film, comprising a non-heterocyclic compound (A) with a weight-average molecular weight of 1500 or less, an organic solvent, and particles with an average particle size of 3 nm or less as measured by dynamic light scattering. The compound (A) is a reaction product obtained by reacting a compound having 2 to 4 epoxy groups linked by ester bonds, ether bonds, alkylene groups with 1 to 10 carbon atoms and / or nitrogen atoms, and containing hydrogen atoms that can be replaced by alkyl groups with 1 to 10 carbon atoms, alkenyl groups with 3 to 6 carbon atoms and / or ketyl groups, with an organic group that can react with epoxy groups and whose terminal part has a 1,2-ethylene glycol structure.

8. The composition for forming a resist underlayer as described in claim 7 has excellent embedding properties for narrow gaps on a semiconductor substrate.

9. The composition for forming a resist underlayer film as claimed in claim 7, wherein compound (A) comprises the following partial structure: In formula (1), Ar represents a benzene ring, naphthalene ring, or anthracene ring that can be substituted by a substituent, and X 1 Indicates ether or ester bond, X 2 Indicates ether bond, ester bond, thioether bond, or -NX 3 -, X 3 It represents a hydrogen atom or a methyl group.

10. The composition for forming a resist underlayer film as described in claim 9, wherein X of formula (1) above... 1 X represents an ether bond. 2 This indicates a thioether bond.

11. The composition for forming a resist underlayer film as claimed in claim 7, further comprising an acid catalyst and / or a crosslinking agent.

12. A resist underlayer film, characterized in that, It is a sintered product of a coating film formed by the composition for forming a resist underlayer film according to any one of claims 7 to 11.

13. A method for manufacturing a substrate with a protective film, characterized in that, For use in manufacturing semiconductors, and comprising the step of coating the protective film forming composition of any one of claims 1 to 5 onto a semiconductor substrate having a height difference and firing it to form a protective film.

14. A method for manufacturing a substrate with a resist pattern, characterized in that, Used for manufacturing semiconductors, and comprising: The step of coating the protective film forming composition or the resist underlayer film forming composition according to any one of claims 1 to 5 or claims 7 to 11 onto a semiconductor substrate and firing it to form a protective film as a resist underlayer film; as well as A resist film is formed on the protective film, followed by exposure and development to form the resist pattern.

15. A method for manufacturing a semiconductor device, comprising the following steps: A protective film is formed on a semiconductor substrate on which an inorganic film can be formed. The protective film forming composition according to any one of claims 1 to 5 is used to form a protective film. A resist pattern is formed on the protective film. Using the resist pattern as a mask, the protective film is dry-etched to expose the surface of the inorganic film or the semiconductor substrate. Using the dry-etched protective film as a mask, the inorganic film or the semiconductor substrate is wet-etched using a semiconductor wet etching solution, and then cleaned.

16. A method for manufacturing a semiconductor device, comprising the following steps: A photoresist underlayer film is formed on a semiconductor substrate on which an inorganic film can be formed. The photoresist underlayer film is formed using the composition for forming a photoresist underlayer film according to any one of claims 7 to 11. A resist pattern is formed on the lower resist film. Using the resist pattern as a mask, the underlying resist film is dry-etched to expose the surface of the inorganic film or the semiconductor substrate. The inorganic film or the semiconductor substrate is etched using the dry-etched resist underlayer as a mask.

Images