Composition for forming resist underlayer film, resist underlayer film, method for forming resist pattern, and method for manufacturing semiconductor device

Abstract

This composition for forming a resist underlayer film contains a solvent and a resin (G) that has a plurality of composite unit structures. The composite unit structures each have a unit structure (A) that has a naphthalene ring having one or two phenolic hydroxyl groups, and a unit structure (B) that has one or more carbon atoms. The resin (G) is obtained by a reaction for forming a covalent bond between a carbon atom that constitutes the naphthalene ring of the unit structure (A) and a carbon atom in the unit structure (B). The first composite unit structure includes, as the unit structure (B), a unit structure (B-I) that has a naphthalene ring, and the second composite unit structure includes, as the unit structure (B), a unit structure (B-II) that has a benzene ring.

Description

Composition for forming resist underlayer film, resist underlayer film, method for forming resist pattern, and method for manufacturing semiconductor device

[0001] The present invention relates to a composition for forming a resist underlayer film, a resist underlayer film, a method for forming a resist pattern, and a method for manufacturing a semiconductor device.

[0002] In recent years, semiconductor manufacturing processes have progressed rapidly, and this has led to a strong demand for higher quality and improved properties of resist underlayer films (see, for example, Patent Documents 1 to 6). In particular, resist underlayer films, which are known to be made of high-carbon materials, are strongly required to have anti-reflection properties (having excellent optical constants to suppress reflection).

[0003] US Patent Application Publication No. 2016 / 311975 Specification International Publication No. 2018 / 198960 Pamphlet Japanese Patent Application Laid-Open No. 2021-81686 Japanese Patent Application Laid-Open No. 2020-105513 International Publication No. 2013 / 146670 Pamphlet Japanese Patent Application Laid-Open No. 2016-151024

[0004] The properties required for a resist underlayer film include, for example, increased hardness and film density so that the pattern does not collapse or bend after etching, and these properties still need to be improved as a material. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition for forming a resist underlayer film that has excellent optical constants for suppressing reflection and that can further increase the hardness and film density of the resist underlayer film, as well as a method for forming a resist underlayer film and a resist pattern, and a method for manufacturing a semiconductor device, using the composition for forming a resist underlayer film.

[0005] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved, and have completed the present invention having the following gist.

[0006] That is, the present invention encompasses the following aspects. [1] A composition for forming a resist underlayer film, comprising: a resin (G) having a plurality of composite unit structures; and a solvent, wherein the composite unit structures include: a unit structure (A) having a naphthalene ring having one or two phenolic hydroxyl groups; and a unit structure (B) having one or more carbon atoms, wherein the resin (G) is a resin obtained by a reaction to form a covalent bond between a carbon atom constituting the naphthalene ring of the unit structure (A) and a carbon atom in the unit structure (B), wherein the first composite unit structure includes, as the unit structure (B), a unit structure (B-I) having a naphthalene ring, and the second composite unit structure includes, as the unit structure (B), a unit structure (B-II) having a benzene ring. [2] The composition for forming a resist underlayer film according to [1], wherein the first composite unit structure is represented by the following formula (1), and the second composite unit structure is represented by the following formula (2): (In formula (1), n1 represents 1 or 2.) (In formula (2), n2 represents 1 or 2, R represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms, and m represents an integer of 1 to 5, and when m is 2 or more, R may be different or may be the same.) [3] The composition for forming a resist underlayer film according to [1] or [2], wherein in the resin (G), a molar ratio of the unit structure (B-I) to the unit structure (B-II) is 20:80 to 80:20. [4] The composition for forming a resist underlayer film according to any one of [1] to [3], wherein the resin (G) is synthesized from reaction raw materials including hydroxynaphthalene having one or two phenolic hydroxyl groups, naphthaldehyde, and a benzaldehyde derivative, and in the benzaldehyde derivative, at least one hydrogen atom bonded to a carbon atom constituting a benzene ring of the benzaldehyde is substituted with a hydroxy group or an alkoxy group having 1 to 6 carbon atoms. [5] The composition for forming a resist underlayer film according to any one of [1] to [4], wherein the solvent comprises a solvent having a boiling point of 160°C or higher. [6] The composition for forming a resist underlayer film according to any one of [1] to [5], further comprising at least one selected from the group consisting of acids and salts thereof, and acid generators. [7] The composition for forming a resist underlayer film according to any one of [1] to [6], further comprising a crosslinking agent. [8] The composition for forming a resist underlayer film according to [7], wherein the crosslinking agent is at least one selected from the group consisting of aminoplast crosslinking agents and phenoplast crosslinking agents. [9] The composition for forming a resist underlayer film according to any one of [1] to [8], further comprising a surfactant.

[10] A resist underlayer film on a semiconductor substrate, which is a cured product of the composition for forming a resist underlayer film according to any one of [1] to [9].

[11] A method for forming a resist pattern used in semiconductor production, comprising the steps of applying the composition for forming a resist underlayer film according to any one of [1] to [9] onto a semiconductor substrate and baking the coating.

[12] A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using the composition for forming a resist underlayer film according to any one of [1] to [9]; forming a resist film on the resist underlayer film; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the resist underlayer film through the resist pattern to form a patterned resist underlayer film; and processing a semiconductor substrate through the patterned resist underlayer film.

[13] A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using the composition for forming a resist underlayer film according to any one of [1] to [9]; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and processing a semiconductor substrate through the patterned resist underlayer film.

[14] A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using the composition for forming a resist underlayer film according to any one of [1] to [9]; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; and processing a semiconductor substrate through the patterned resist underlayer film.

[15] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using the composition for forming a resist underlayer film according to any one of [1] to [9]; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; forming a vapor-deposited film on the resist underlayer film after removing the hard mask; processing the vapor-deposited film by etching; removing the patterned resist underlayer film to leave a patterned vapor-deposited film; and processing a semiconductor substrate through the patterned vapor-deposited film.

[16] The method for manufacturing a semiconductor device according to any one of

[13] to

[15] , wherein the hard mask is formed by applying a composition containing an inorganic substance or vapor-depositing an inorganic substance.

[17] The method for manufacturing a semiconductor device according to any one of

[12] to

[16] , wherein the resist film is patterned by a nanoimprint method or a self-assembled film.

[18] The method for manufacturing a semiconductor device according to

[14] or

[15] , wherein the hard mask is removed by etching or an alkaline chemical solution.

[0007] According to the present invention, it is possible to provide a composition for forming a resist underlayer film that has excellent optical constants for suppressing reflection and can further increase the hardness and film density of a resist underlayer film, as well as a method for forming a resist underlayer film and a resist pattern, and a method for manufacturing a semiconductor device, which use the composition for forming a resist underlayer film.

[0008] [Composition for Forming a Resist Underlayer Film] The composition for forming a resist underlayer film of the present invention includes a resin (G) having a plurality of composite unit structures and a solvent. The composite unit structure includes a unit structure (A) having a naphthalene ring having one or two phenolic hydroxyl groups, and a unit structure (B) having one or more carbon atoms. The resin (G) is a resin obtained by a reaction that forms a covalent bond between a carbon atom constituting the naphthalene ring of the unit structure (A) and a carbon atom in the unit structure (B). The first composite unit structure includes a unit structure (BI) having a naphthalene ring as the unit structure (B). The second composite unit structure includes a unit structure (B-II) having a benzene ring as the unit structure (B). In this specification, the resin (G) may be referred to as a "novolac resin." By including the above-described unit structures (A) and (B), the resin (G) can provide a composition for forming a resist underlayer film that has excellent optical constants for suppressing reflection and can further increase the hardness and film density of the resist underlayer film.

[0009] The first complex unit structure is one of the multiple complex unit structures contained in resin (G). The second complex unit structure is one of the multiple complex unit structures contained in resin (G). Resin (G) is a single resin having multiple complex unit structures, and does not refer to a mixture of two or more resins having different complex unit structures. Unit structure (BI) and unit structure (B-II) are subordinate concepts of unit structure (B), and do not refer to partial structures of unit structure (B).

[0010] [I. Definitions of Terms] In this specification, definitions of main terms related to the novolac resin, which is one embodiment of the present invention, are explained below. Unless otherwise specified, the following definitions of each term apply to the novolac resin.

[0011] (I-1) "Novolac Resin" The term "novolac resin" is used in a broad sense to encompass not only phenol-formaldehyde resins (so-called novolac phenolic resins) and aniline-formaldehyde resins (so-called novolac aniline resins) in the narrow sense, but also resins formed by forming a covalent bond (substitution reaction, addition reaction, condensation reaction, addition-condensation reaction, etc.) between an organic compound having a functional group capable of forming a covalent bond with an aromatic ring (for example, an aldehyde group; a ketone group; an acetal group; a ketal group; a hydroxyl group or an alkoxy group bonded to a secondary or tertiary carbon atom; a hydroxyl group, an alkoxy group, or a halo group bonded to the α-carbon atom (e.g., the benzylic carbon atom) of an alkylaryl group; or a carbon-carbon unsaturated bond such as in divinylbenzene or dicyclopentadiene) in the presence of an acid catalyst or under equivalent reaction conditions, and an aromatic ring in a compound having an aromatic ring (preferably having heteroatoms such as oxygen, nitrogen, and sulfur atoms as atoms constituting the aromatic ring or atoms bonded to the aromatic ring)

[0012] Therefore, the novolak resin referred to in this specification is a resin formed by linking a plurality of compounds having aromatic rings together, with an organic compound containing a carbon atom derived from the functional group (sometimes referred to as a "linking carbon atom") forming a covalent bond with an aromatic ring in a compound having an aromatic ring via the linking carbon atom.

[0013] In this specification, the terms unit structure (A) and unit structure (B) are used to refer to the unit structures constituting a "novolac resin." Unit structure (A) is a unit structure derived from a naphthalene ring having one or two phenolic hydroxyl groups. Unit structure (B) is a unit structure derived from a compound having an aldehyde group that enables covalent bonding with the naphthalene ring of unit structure (A).

[0014] <Resin (G)> Resin (G) has a composite unit structure. The composite unit structure has a unit structure (A) having a naphthalene ring having one or two phenolic hydroxyl groups, and a unit structure (B) having one or more carbon atoms.

[0015] The composite unit structure of the resin (G) is represented, for example, by the following formula (AB). (In formula (AB), A represents the unit structure (A), and B represents the unit structure (B).)

[0016] <<Unit Structure (A)>> The unit structure (A) has a naphthalene ring having one or two phenolic hydroxyl groups.

[0017] The naphthalene ring in the unit structure (A) may have a substituent. However, the naphthalene ring in the unit structure (A) does not have three or more phenolic hydroxyl groups (hydroxy groups). Examples of the substituent include a halo group (halogen atom), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxy group, a hydroxyalkyl group, a carboxy group, a formyl group, a cyano group, a nitro group, an ester group, an amide group, a sulfonyl-containing group, a thiol group, a sulfide-containing group, and an ether bond-containing group. Examples of the alkyl group include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms. Examples of the alkenyl group include linear, branched, or cyclic alkenyl groups having 2 to 10 carbon atoms. Examples of the alkynyl group include linear, branched, or cyclic alkynyl groups having 2 to 10 carbon atoms. Examples of the alkoxy group include a group represented by -OR. Here, R is a saturated or unsaturated, linear, branched or cyclic hydrocarbon group (-R ａ The alkoxy group may have, for example, 1 to 20 carbon atoms. The aryl group may have 6 to 30 carbon atoms. The aryloxy group may have 6 to 30 carbon atoms. The amino group may have -NH ２ , —NHR or —NR ２ Here, R is the hydrocarbon group -R ａ represents -NR ２ In the formula, the two R's may be the same or different. Examples of the hydroxyalkyl group include linear, branched, or cyclic hydroxyalkyl groups having 1 to 20 carbon atoms. Examples of the ester group include -CO２ Examples of the hydrocarbon group include a group represented by -R or -OCOR. ａ The amide group is —NHCOR, —CONHR, —NRCOR, or —CONR ２ Here, R is the hydrocarbon group -R ａ When there are two R's, the two R's may be the same or different. The sulfonyl-containing group includes -SO ２ Here, R is the hydrocarbon group -R ａ or a hydroxy group -OH. Examples of sulfide-containing groups include groups represented by -SR, where R is the hydrocarbon group -R ａ The ether bond-containing group is represented by R １１ -O-R １１ In this case, R １１ each independently represents an alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group, or an aryl group, such as a phenyl group, a naphthyl group, an anthranyl group, or a pyrenyl group. The ether bond-containing group may be an organic group containing an ether bond, such as a methoxy group, an ethoxy group, or a phenoxy group.

[0018] Examples of the naphthalene ring having one or two phenolic hydroxyl groups contained in the unit structure (A) include those represented by the following structural formulas.

[0019] <<Unit Structure (B)>> The unit structure (B) has one or more carbon atoms. Examples of the unit structure (B) include unit structures derived from an aldehyde compound. The unit structure (B) is one or more types of unit structures containing a linking carbon atom bonding to an aromatic ring in the unit structure (A) [see (I-1) above], and includes, for example, a structure represented by the formula (1) or (2) shown below. The unit structure (B) can link two unit structures (A) by forming a covalent bond with the unit structure (A).

[0020] <<<<Unit Structure (BI)>>> The unit structure (BI) has a naphthalene ring. The unit structure (BI) is preferably a unit structure derived from naphthaldehyde. The naphthaldehyde may be 1-naphthaldehyde or 2-naphthaldehyde.

[0021] The naphthalene ring in the unit structure (BI) may have a substituent, and examples of the substituent include those described above for the unit structure (A).

[0022] <<<<Unit Structure (B-II)>>> The unit structure (B-II) has a benzene ring. The unit structure (B-II) is preferably a unit structure derived from benzaldehyde (hereinafter also referred to as a "benzaldehyde derivative") in which a hydrogen atom bonded to a carbon atom constituting the benzene ring has been substituted with a hydroxy group or an alkoxy group.

[0023] The benzene ring in the unit structure (B-II) may have a substituent, and examples of the substituent include those described above for the unit structure (A).

[0024] Examples of the benzaldehyde derivative from which the unit structure (B-II) is derived include aldehydes represented by the following formula:

[0025] Resin (G) has, as unit structures (B), a first composite unit structure including a unit structure (BI) having a naphthalene ring, and a second composite unit structure including a unit structure (B-II) having a benzene ring. The first composite unit structure and the second composite unit structure may be bonded regularly or randomly. Furthermore, resin (G) may have a composite unit structure other than the first composite unit structure and the second composite unit structure.

[0026] The first complex unit structure is preferably a complex unit structure represented by the following formula (1). (In formula (1), n1 represents 1 or 2.)

[0027] In formula (1), n1 is 1 or 2. When n1 is 2, the two hydroxy groups may be bonded to one ring or to different rings in the naphthalene ring.

[0028] The second composite unit structure is preferably a composite unit structure represented by the following formula (2). (In formula (2), n2 represents 1 or 2; R represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms; m represents an integer of 1 to 5; and when m is 2 or greater, R may be different from or the same as each other.)

[0029] Examples of the alkoxy group having 1 to 6 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- Examples thereof include a methyl-n-pentyloxy group, a 4-methyl-n-pentyloxy group, a 1,1-dimethyl-n-butoxy group, a 1,2-dimethyl-n-butoxy group, a 1,3-dimethyl-n-butoxy group, a 2,2-dimethyl-n-butoxy group, a 2,3-dimethyl-n-butoxy group, a 3,3-dimethyl-n-butoxy group, a 1-ethyl-n-butoxy group, a 2-ethyl-n-butoxy group, a 1,1,2-trimethyl-n-propoxy group, a 1,2,2-trimethyl-n-propoxy group, a 1-ethyl-1-methyl-n-propoxy group, and a 1-ethyl-2-methyl-n-propoxy group.

[0030] In formula (2), m is an integer of 1 to 5, preferably 1 to 3, and may be 1. When m is 2 or more, R may be different from each other or may be the same.

[0031] In addition, the hydrogen atoms bonded to the naphthalene ring or the benzene ring in the unit structure (A) and the unit structure (B) may be replaced with a substituent. Examples of the substituent include the substituents (S) represented by the following formulae (S1) to (S7).

[0032] (In formulas (S1) to (S7), R ｓａ represents a monovalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms. ｓｂ R each independently represents a single bond or a divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms. ｓｃ R each independently represents a divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms. ｓｄ ａｌｋｙｎｙｌ each independently represents an alkynyl group having 2 to 4 carbon atoms. ｓａ each independently represents a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. ｓｂ each independently represents a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms. ｓａ and X ｓｂ each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or X ｓａ and X ｓｂ together with the carbon atom bonded to the hydroxy group, form a carbonyl group. n represents an integer of 0 to 5. * represents a bond.

[0033] <R ｓａ > R ｓａ Examples of the monovalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms and monovalent unsaturated hydrocarbon groups having 2 to 10 carbon atoms.

[0034] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, and a 1-ethyl-n-propyl group. 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 group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,Examples include a 3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-1-methyl-cyclopropyl group, a 2-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-3-methyl-cyclopropyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

[0035] The monovalent unsaturated hydrocarbon group having 2 to 10 carbon atoms has one or more carbon-carbon multiple bonds. When the monovalent unsaturated hydrocarbon group having 2 to 10 carbon atoms has two or more carbon-carbon multiple bonds, the two or more carbon-carbon multiple bonds may all be carbon-carbon double bonds, all may be carbon-carbon triple bonds, or may be a mixture of carbon-carbon double bonds and carbon-carbon triple bonds. The two or more carbon-carbon multiple bonds may or may not be conjugated.

[0036] <R ｓｂ , and R ｓｃ > R ｓｂ , and R ｓｃ In the formula, examples of the divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms include an alkylene group having 1 to 10 carbon atoms and a divalent unsaturated hydrocarbon group having 2 to 10 carbon atoms. The divalent unsaturated hydrocarbon group having 2 to 10 carbon atoms has one or more carbon-carbon multiple bonds. When the divalent unsaturated hydrocarbon group having 2 to 10 carbon atoms has two or more carbon-carbon multiple bonds, the two or more carbon-carbon multiple bonds may all be carbon-carbon double bonds, all may be carbon-carbon triple bonds, or may be a mixture of carbon-carbon double bonds and carbon-carbon triple bonds. The two or more carbon-carbon multiple bonds may or may not be conjugated. R ｓｂ , and R ｓｃ Examples of the group include the following groups: (* represents a bond.)

[0037] <R ｓｄ ａｌｋｙｎｙｌ > R ｓｄ ａｌｋｙｎｙｌrepresents an alkynyl group having 2 to 4 carbon atoms. Examples of the alkynyl group having 2 to 4 carbon atoms include an ethynyl group, a 1-propynyl group, and a propargyl group (2-propynyl group).

[0038] <Ar ｓａ > Ar ｓａ The monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms in the formula (I) is a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon having 6 to 20 carbon atoms. Examples of aromatic hydrocarbons having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, perinaphthane, pyrene, fluorene, and biphenyl.

[0039] <Ar ｓｂ > Ar ｓｂ The divalent aromatic hydrocarbon group having 6 to 20 carbon atoms in the formula (I) is a residue obtained by removing two hydrogen atoms from an aromatic hydrocarbon having 6 to 20 carbon atoms. Examples of aromatic hydrocarbons having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, pyrene, fluorene, and biphenyl.

[0040] <X ｓａ and X ｓｂ > X ｓａ and X ｓｂ In the formula (I), examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. Examples of the monovalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group having 1 to 10 carbon atoms. A monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms is a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon having 6 to 20 carbon atoms. Examples of aromatic hydrocarbons having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, perinaphthane, pyrene, fluorene, and biphenyl.

[0041] Examples of the substituent represented by formula (S1) include the following groups. (* represents a bond.)

[0042] Examples of the substituent represented by formula (S2) include the following groups. (* represents a bond.)

[0043] Examples of the substituent represented by formula (S3) include the following groups. (* represents a bond.)

[0044] Examples of the substituent represented by formula (S4) include the following groups. (* represents a bond.)

[0045] Examples of the substituent represented by formula (S5) include the following groups. (* represents a bond.)

[0046] Examples of the substituent represented by formula (S6) include the following groups. (* represents a bond.)

[0047] Examples of the substituent represented by formula (S7) include the following groups. (* represents a bond.)

[0048] Examples of other substituents include the following groups: (* represents a bond.)

[0049] The composite unit structure in the resin (G) may contain a unit structure other than the unit structure (A) and the unit structure (B). Examples of such unit structures include a unit structure having a heterocycle.

[0050] Resin (G) is preferably a resin synthesized from reaction raw materials including hydroxynaphthalene having one or two phenolic hydroxyl groups, naphthaldehyde, and a benzaldehyde derivative. Examples of hydroxynaphthalene having one or two phenolic hydroxyl groups include the structural formulas exemplified in the unit structure (A) described above. Examples of naphthaldehyde include 1-naphthaldehyde and 2-naphthaldehyde. Examples of benzaldehyde derivatives include the aldehydes exemplified in the unit structure (B-II) described above.

[0051] The novolak resin having the structure represented by formula (AB) can be prepared by a known method. For example, it can be prepared by condensing a ring-containing compound represented by H-A-H with an aldehyde compound represented by OHC-B. In the formula, A and B have the same meanings as above.

[0052] The ring-containing compound and the aldehyde compound may each be used alone or in combination of two or more. In this condensation reaction, the aldehyde compound can be used in an amount of 0.1 to 10 moles, preferably 0.1 to 2 moles, per mole of the ring-containing compound.

[0053] Examples of the catalyst used in the condensation reaction include mineral acids such as sulfuric acid, phosphoric acid, and perchloric acid, organic sulfonic acids such as p-toluenesulfonic acid, p-toluenesulfonic acid monohydrate, methanesulfonic acid, and trifluoromethanesulfonic acid, and carboxylic acids such as formic acid and oxalic acid. The amount of catalyst used varies depending on the type of catalyst used, but is usually 0.001 to 10,000 parts by mass, preferably 0.01 to 1,000 parts by mass, and more preferably 0.05 to 100 parts by mass per 100 parts by mass of the ring-containing compound (or the total amount of ring-containing compounds when multiple types are used).

[0054] The condensation reaction can be carried out without a solvent, but is usually carried out using a solvent. The solvent is not particularly limited as long as it can dissolve the reaction substrates and does not inhibit the reaction. Examples of the solvent include 1,2-dimethoxyethane, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, tetrahydrofuran, tetrahydropyran, dioxane, 1,2-dichloromethane, 1,2-dichloroethane, toluene, N-methylpyrrolidone, and dimethylformamide. The condensation reaction temperature is usually 40°C to 200°C, preferably 100°C to 180°C. The reaction time varies depending on the reaction temperature, but is usually 5 minutes to 50 hours, preferably 5 minutes to 24 hours.

[0055] The weight average molecular weight of the novolak resin according to one embodiment of the present invention is usually 500 to 100,000, preferably 600 to 50,000, 700 to 10,000, or 800 to 8,000.

[0056] The content of the resin (G) in the composition for forming a resist underlayer film is, for example, preferably 25 to 100 mass %, more preferably 50 to 100 mass %, and even more preferably 70 to 100 mass %, based on the mass of the film-forming components. Here, the film-forming components refer to the components remaining after excluding the solvent component from the composition for forming a resist underlayer film.

[0057] The molar ratio ((A):(B)) of the unit structure (A) to the unit structure (B) in the resin (G) is, for example, preferably 30:70 to 70:30, and more preferably 40:60 to 60:40. The molar ratio of the unit structure (A) to the unit structure (B) in the resin (G) can also be expressed as the molar ratio of the compound (A) that serves as the raw material for the unit structure (A) to the compound (B) that serves as the raw material for the unit structure (B). The molar ratio ((A):(B)) of the compound (A) to the compound (B) is, for example, preferably 30:70 to 70:30, and more preferably 40:60 to 60:40. Here, the compound (A) may be one type or two or more types. Similarly, the compound (B) may be one type or two or more types.

[0058] In the resin (G), the total content (molar ratio) of the unit structure (B) of the unit structure (B-I) and the unit structure (B-II) is, for example, preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and may be 100 mol%. The total molar ratio of the unit structure (B-I) and the unit structure (B-II) in the unit structure (B) can also be expressed as the total molar ratio of the compound (B-I) that serves as the raw material for the unit structure (B-I) in the compound (B) and the compound (B-II) that serves as the raw material for the unit structure (B-II). The total molar ratio of the compound (B-I) and the compound (B-II) in the compound (B) is, for example, preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and may be 100 mol%.

[0059] The molar ratio ((B-I):(B-II)) of the unit structure (B-I) to the unit structure (B-II) in the resin (G) is, for example, preferably 20:80 to 80:20, and more preferably 30:70 to 70:30. The molar ratio of the unit structure (B-I) to the unit structure (B-II) in the resin (G) can also be expressed as the molar ratio of the compound (B-I) that serves as the raw material for the unit structure (B-I) to the compound (B-II) that serves as the raw material for the unit structure (B-II). The molar ratio ((B-I):(B-II)) of the compound (B-I) to the compound (B-II) is, for example, preferably 20:80 to 80:20, and more preferably 30:70 to 70:30.

[0060] The molar ratio of the first composite unit structure to the second composite unit structure in the resin (G) can be expressed as the molar ratio of the unit structure (BI) to the unit structure (B-II) in the resin (G) ((BI):(B-II)). That is, the molar ratio of the first composite unit structure to the second composite unit structure in the resin (G) is, for example, preferably 20:80 to 80:20, and more preferably 30:70 to 70:30.

[0061] <Solvent> The composition for forming a resist underlayer film, which is one embodiment of the present invention, contains a solvent.

[0062] The solvent is not particularly limited as long as it can dissolve the specific novolak resin and other optional components added as needed.

[0063] Examples of the solvent include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate,Isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate Examples of suitable solvents include methyl acetoacetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

[0064] Also, solvents with boiling points of 160°C or higher can be included in combination with solvents with boiling points below 160°C.

[0065] As such a high-boiling point solvent, for example, the following compounds described in WO 2018 / 131562 (A1) can be preferably used.

[0066] [R in formula (i)] １ , R ２ and R ３each represent a hydrogen atom, an oxygen atom, a sulfur atom, or an alkyl group having 1 to 20 carbon atoms which may be interrupted by an amide bond, and may be the same or different from each other and may be bonded to each other to form a ring structure.] Alternatively, 1,6-diacetoxyhexane (boiling point 260°C) and tripropylene glycol monomethyl ether (boiling point 242°C) described in JP-A No. 2021-84974, as well as various other high-boiling point solvents described in paragraph 0082 of the same publication, can be preferably used.

[0067] Alternatively, dipropylene glycol monomethyl ether acetate (boiling point 213°C), diethylene glycol monoethyl ether acetate (boiling point 217°C), diethylene glycol monobutyl ether acetate (boiling point 247°C), dipropylene glycol dimethyl ether (boiling point 171°C), dipropylene glycol monomethyl ether (boiling point 187°C), dipropylene glycol monobutyl ether (boiling point 231°C), tripropylene glycol monomethyl ether (boiling point 247°C), di ... Preferred examples of high-boiling solvents that can be used include dimethyl ether (boiling point 242°C), γ-butyrolactone (boiling point 204°C), benzyl alcohol (boiling point 205°C), propylene carbonate (boiling point 242°C), tetraethylene glycol dimethyl ether (boiling point 275°C), 1,6-diacetoxyhexane (boiling point 260°C), dipropylene glycol (boiling point 230°C), 1,3-butylene glycol diacetate (boiling point 232°C), and various other high-boiling solvents described in paragraphs 0023 to 0031 of the publication.

[0068] The composition for forming a resist underlayer film, which is one embodiment of the present invention, may contain an acid and / or a salt thereof and / or an acid generator.

[0069] Examples of the acid include p-toluenesulfonic acid, trifluoromethanesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid.

[0070] The salt may be a salt of the above-mentioned acid, and is not limited thereto, but suitable salts include ammonia derivative salts such as trimethylamine salts and triethylamine salts, pyridine derivative salts, and morpholine derivative salts.

[0071] The acid and / or salt thereof may be used singly or in combination of two or more kinds, and the blending amount is usually 0.0001 to 20 mass %, preferably 0.0005 to 10 mass %, and more preferably 0.01 to 5 mass %, based on the total solid content.

[0072] Examples of the acid generator include a thermal acid generator and a photoacid generator.

[0073] Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG2689, and TAG2700 (manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), and other organic sulfonic acid alkyl esters.

[0074] Photoacid generators generate acid when the resist is exposed to light. This allows the acidity of the underlayer film to be adjusted. This is one way to match the acidity of the underlayer film to that of the upper layer resist. Adjusting the acidity of the underlayer film also allows for adjustment of the pattern shape of the upper layer resist.

[0075] Examples of the photoacid generator contained in the composition for forming a resist underlayer film of the present invention include an onium salt compound, a sulfonimide compound, and a disulfonyldiazomethane compound.

[0076] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0077] Examples of sulfonimide compounds include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0078] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0079] The acid generators may be used singly or in combination of two or more.

[0080] When an acid generator is used, the proportion thereof is 0.01 to 10 parts by mass, or 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass, relative to 100 parts by mass of the solid content of the composition for forming a resist underlayer film.

[0081] The composition for forming a resist underlayer film, which is one embodiment of the present invention, may contain, in addition to the above, a crosslinking agent, a surfactant, a light absorbing agent, a rheology adjuster, an adhesion aid, and the like, as necessary.

[0082] Representative examples of the crosslinking agent include an aminoplast crosslinking agent and a phenoplast crosslinking agent.

[0083] As the crosslinking agent, a crosslinking agent having high heat resistance can be used, and as the crosslinking agent having high heat resistance, a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used.

[0084] Aminoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, and polymers thereof. Crosslinking agents having at least two crosslink-forming substituents are preferred, including compounds such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, and methoxymethylated thiourea. Condensates of these compounds can also be used.

[0085] Preferably, it is at least one selected from the group consisting of tetramethoxymethyl glycoluril and hexamethoxymethyl melamine.

[0086] Some specific examples are as follows:

[0087]

[0088] Phenoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatics, their polymers, and the like. Preferred crosslinking agents have at least two crosslink-forming substituents per molecule, such as 2,6-dihydroxymethyl-4-methylphenol, 2,4-dihydroxymethyl-6-methylphenol, bis(2-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, bis(4-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, bis(3-formyl-4-hydroxyphenyl)methane, bis(4-hydroxy-2,5-dimethylphenyl)formylmethane, and α,α-bis(4-hydroxy-2,5-dimethylphenyl)-4-formyltoluene. Condensates of these compounds can also be used.

[0089] In addition to the above, other examples of such compounds include compounds having a partial structure of the following formula (4) and polymers or oligomers having a repeating unit of the following formula (5).

[0090] The above R １１ , R １２ , R １３ , and R １４ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the above-mentioned examples of these alkyl groups can be used. n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) is an integer of 2 to 5. n3 is an integer of 1 to 4, n4 is an integer of 0 to (4-n3), and (n3+n4) is an integer of 1 to 4. Oligomers and polymers having a repeating unit structure number of 2 to 100 or 2 to 50 can be used.

[0091] Some specific examples are as follows:

[0092]

[0093]

[0094]

[0095]

[0096] The crosslinking agents, such as aminoplast crosslinking agents and phenoplast crosslinking agents, may be used alone or in combination of two or more. The aminoplast crosslinking agent may be produced by a known method or a method equivalent thereto, or a commercially available product may be used.

[0097] The amount of the crosslinking agent, such as an aminoplast crosslinking agent or a phenoplast crosslinking agent, used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, and the like, but is 0.001 mass % or more, 0.01 mass % or more, 0.05 mass % or more, 0.5 mass % or more, or 1.0 mass % or more, and is 80 mass % or less, 50 mass % or less, 40 mass % or less, 20 mass % or less, or 10 mass % or less, relative to the total solids content of the composition for forming a resist underlayer film of the present invention.

[0098] The composition for forming a resist underlayer film according to the present invention can contain a surfactant in order to prevent pinholes, striations, etc., and to further improve the coatability against surface irregularities.

[0099] Examples of surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. Examples of suitable surfactants include fluorosurfactants such as EFTOP EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, R-30, and R-40 (trade names, manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), and Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0100] The amount of these surfactants to be added is usually 2.0 mass % or less, and preferably 1.0 mass % or less, based on the total solid content of the composition for forming a resist underlayer film of the present invention. These surfactants may be added alone or in combination of two or more.

[0101] Examples of the light absorber include commercially available light absorbers described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as C.I. 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; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; C.I. C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 96; C.I. Fluorescent Brightening Agent 112, 135, and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; C.I. Pigment Green 10; C.I. Pigment Brown 2, etc. can be suitably used. 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 composition for forming a resist underlayer film according to the present invention.

[0102] The rheology modifier is added primarily to improve the fluidity of the resist underlayer film-forming composition, thereby improving the film thickness uniformity of the resist underlayer film and the ability of the resist underlayer film-forming composition to fill holes, particularly during the baking process. 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 blended in an amount of less than 30% by mass based on the total solids content of the resist underlayer film-forming composition of the present invention.

[0103] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the composition for forming a resist underlayer film, and particularly to prevent peeling of the resist during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; vinyltrichlorosilane; Examples of the adhesion promoter include silanes such as silane, 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 ureas such as 1,1-dimethylurea and 1,3-dimethylurea, or thiourea compounds. 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 composition for forming a resist underlayer film according to the present invention.

[0104] The solids content of the composition for forming a resist underlayer film according to the present invention is 0.1 to 70% by mass, or 0.1 to 60% by mass. The solids content is the content of all components excluding the solvent from the composition for forming a resist underlayer film. The solids content may contain a crosslinkable resin in an amount of 1 to 99.9% by mass, or 50 to 99.9% by mass, or 50 to 95% by mass, or 50 to 90% by mass.

[0105] [Resist Underlayer Film] The resist underlayer film can be formed, for example, as follows using the composition for forming a resist underlayer film according to the present invention.

[0106] Substrates used in the manufacture of semiconductor devices (e.g., silicon wafer substrates, silicon dioxide coated substrates (SiO ２ The resist underlayer film forming composition according to one embodiment of the present invention is applied onto a substrate (e.g., a silicon nitride substrate (SiN substrate), a silicon oxynitride substrate (SiON substrate), a titanium nitride substrate (TiN substrate), a tungsten substrate (W substrate), a glass substrate, an ITO substrate, a polyimide substrate, or a substrate coated with a low dielectric constant material (low-k material)) by a suitable application method such as a spinner or coater, and then baked using a heating means such as a hot plate to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 80°C to 800°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 500°C and the baking time is 0.5 to 2 minutes. The atmospheric gas during baking may be air, or an inert gas such as nitrogen or argon. In one embodiment, an oxygen concentration of 1% or less is particularly preferred. The thickness of the underlayer film formed here is, for example, 10 to 1000 nm, 20 to 500 nm, 30 to 400 nm, or 50 to 300 nm. Furthermore, if a quartz substrate is used as the substrate, a replica of the quartz imprint mold (mold replica) can be produced.

[0107] Furthermore, an adhesion layer and / or a silicon-containing layer containing 99% by mass or less, or 50% by mass or less of Si can be formed by coating or vapor deposition on the resist underlayer film according to one embodiment of the present invention. For example, an adhesion layer as described in JP-A-2013-202982 or JP-A-5827180, a silicon-containing resist underlayer film (inorganic resist underlayer film) forming composition as described in WO 2009 / 104552 (A1) can be formed by spin coating, or a Si-based inorganic material film can be formed by CVD or the like.

[0108] Furthermore, by applying the composition for forming a resist underlayer film, which is one embodiment of the present invention, to a semiconductor substrate having a portion with a step and a portion without a step (a so-called stepped substrate) and baking it, the step between the portion with a step and the portion without a step can be reduced.

[0109] [Method of Forming a Resist Pattern] The method of forming a resist pattern of the present invention includes at least the step of applying the composition for forming a resist underlayer film of the present invention onto a semiconductor substrate and baking it to form a resist underlayer film. The method of forming a resist pattern of the present invention may also include the following steps: - the step of forming a resist film on the resist underlayer film; - the step of irradiating the resist film with light or an electron beam and then developing the resist film to obtain a resist pattern; and - the step of etching the resist underlayer film using the resist pattern as a mask.

[0110] [Method for manufacturing a semiconductor device] (i) A method for manufacturing a semiconductor device, which is one aspect of the present invention, includes: a step of forming a resist underlayer film on a semiconductor substrate using a composition for forming a resist underlayer film, which is one aspect of the present invention; a step of forming a resist film on the resist underlayer film; a step of forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; a step of etching the resist underlayer film through the resist pattern to form a patterned resist underlayer film; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0111] (ii) A method for manufacturing a semiconductor device, which is an aspect of the present invention, includes the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition, which is an aspect of the present invention; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and processing a semiconductor substrate through the patterned resist underlayer film.

[0112] (iii) A method for manufacturing a semiconductor device, which is an aspect of the present invention, includes the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition, which is an aspect of the present invention; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; and processing the semiconductor substrate through the patterned resist underlayer film.

[0113] (iv) A method for manufacturing a semiconductor device according to one embodiment of the present invention includes the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to one embodiment of the present invention; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; forming a vapor-deposited film (spacer) on the resist underlayer film after removing the hard mask; processing the vapor-deposited film (spacer) by etching; removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and processing a semiconductor substrate through the patterned vapor-deposited film (spacer).

[0114] The manufacturing methods (i) to (iv) above can be used to process a semiconductor substrate.

[0115] The step of forming a resist underlayer film using the composition for forming a resist underlayer film, which is one aspect of the present invention, is as described above in [Resist Underlayer Film].

[0116] A hard mask such as a silicon-containing film may be formed as a second resist underlayer film on the resist underlayer film formed in the above steps, and a resist pattern may be formed thereon [(ii) to (iv) above].

[0117] The hard mask may be a coating film of an inorganic material or a vapor-deposited film of an inorganic material formed by a vapor deposition method such as CVD or PVD, and may be a SiON film, a SiN film, or a SiO ２ An example is a membrane.

[0118] Furthermore, an anti-reflective coating (BARC) may be formed on this hard mask, or a resist shape correction film without anti-reflective properties may be formed.

[0119] In the step of forming the resist pattern, exposure is performed through a mask (reticle) for forming a predetermined pattern or by direct writing. Examples of exposure sources that can be used include g-line, i-line, KrF excimer laser, ArF excimer laser, EUV, and electron beam. After exposure, post-exposure baking is performed as needed. The resist is then developed with a developer (e.g., a 2.38% by mass aqueous solution of tetramethylammonium hydroxide, butyl acetate), and then rinsed with a rinse solution or pure water to remove the used developer. Post-baking is then performed to dry the resist pattern and enhance adhesion to the underlayer.

[0120] The etching step performed after the formation of the resist pattern is performed by dry etching.

[0121] The following gases are used for processing the hard mask (silicon-containing layer), resist underlayer film, and substrate: CF ４ , CHF ３ , C.H. ２ F ２ , CH ３ F, C ４ F ６ , C ４ F ８ , O２ , N ２ O, NO ２ , H ２ , He can be used. These gases may be used alone or in combination of two or more. Furthermore, these gases may be mixed with argon, nitrogen, carbon dioxide, carbonyl sulfide, sulfur dioxide, neon, or nitrogen trifluoride.

[0122] The resist film may be patterned by a nanoimprint method or a self-assembled film method.

[0123] In the nanoimprint method, a resist composition is molded using a patterned mold that is transparent to irradiated light, while in the self-assembled film method, a pattern is formed using a self-assembled film that naturally forms a regular structure on the nanometer order, such as a diblock polymer (e.g., polystyrene-polymethyl methacrylate).

[0124] In the nanoimprint method, before applying the curable composition that will form the resist film, a silicon-containing layer (hard mask layer) may be optionally formed on the resist underlayer film by coating or vapor deposition, and further an adhesion layer may be formed on the resist underlayer film or the silicon-containing layer (hard mask layer) by coating or vapor deposition, and the curable composition that will form the resist film may be applied on the adhesion layer.

[0125] In addition, wet etching may be performed to simplify the process and reduce damage to the processed substrate. This leads to suppression of fluctuations in processing dimensions and reduction of pattern roughness, making it possible to process the substrate with high yield. Therefore, in steps (iii) to (iv), the hard mask can be removed using either etching or an alkaline chemical solution. In particular, when an alkaline chemical solution is used, there are no restrictions on the components, but it is preferable that the alkaline component contains the following:

[0126] Examples of the alkaline component include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide, methyltributylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldiethylammonium hydroxide, benzyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, and (2-hydroxyethyl)trimethylammonium hydroxide, monoethanolamine, diethanolamine, triethanolamine, 2-(2-aminoethoxy)ethanol, N,N-dimethylethanolamine, N,N-diethylethanolamine, N , N-dibutylethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, tetrahydrofurfurylamine, N-(2-aminoethyl)piperazine, 1,8-diazabicyclo[5.4.0]undecene-7, 1,4-diazabicyclo[2.2.2]octane, hydroxyethylpiperazine, piperazine, 2-methylpiperazine, trans-2,5-dimethylpiperazine, cis-2,6-dimethylpiperazine, 2-piperidinemethanol, cyclohexylamine, 1,5-diazabicyclo[4.3.0]nonene-5, etc. Furthermore, particularly from the viewpoint of handling, tetramethylammonium hydroxide and tetraethylammonium hydroxide are particularly preferred, and an inorganic base may be used in combination with the quaternary ammonium hydroxide. As the inorganic base, alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, rubidium hydroxide, etc. are preferred, with potassium hydroxide being more preferred.

[0127] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0128] The weight-average molecular weights Mw of the resins shown in the following Synthesis Examples 1 to 6 and Comparative Synthesis Example 1 are the results of measurement by gel permeation chromatography (hereinafter abbreviated as GPC). A GPC device manufactured by Tosoh Corporation was used for the measurement, and the measurement conditions were as follows: GPC column: TSKgel Super-Multipore HZ-N (2 columns) Column temperature: 40°C Solvent: tetrahydrofuran (THF) Flow rate: 0.35 ml / min Standard sample: polystyrene (manufactured by Tosoh Corporation)

[0129] (1) Synthesis of Polymers Polymers of structural formulae (S1) to (S6) used for resist underlayer films and structural formula (SS1) used for comparative examples were synthesized using Compound Group A, Compound Group B, Catalyst Group C, Solvent Group D, and Reprecipitation Solvent Group E shown below.

[0130] (1-1) Compound groups A to B

[0131] (1-2) Catalyst group C, solvent group D, reprecipitation solvent group E Methanesulfonic acid: C1 Propylene glycol monomethyl ether acetate (=PGMEA): D1 Propylene glycol monomethyl ether (=PGME): D2 Methanol: E1 Methanol / water: E2

[0132] Synthesis Example 1 (Synthesis of Polymer (S1)) (A1 / B1 / B2 = 50 / 35 / 15 (molar ratio)) 10.0 g of A1, 6.8 g of B1, 2.3 g of B2, 0.6 g of methanesulfonic acid, 30.8 g of PGMEA, and 13.2 g of PGME were placed in a flask. The mixture was then heated to 120°C under nitrogen and reacted for approximately 15 hours. After the reaction was stopped, the mixture was reprecipitated in a methanol / water mixed solvent (E2) and dried to obtain Polymer (S1). The weight average molecular weight Mw measured by GPC in terms of polystyrene was approximately 3,100. The obtained polymer was dissolved in PGMEA, and ion exchange was carried out for 4 hours using a cation exchange resin and an anion exchange resin to obtain a solution of the target compound.

[0133] [Synthesis Examples 2 to 6] Polymers (S2) to (S6) were synthesized in the same manner as in Synthesis Example 1 under the conditions shown in Synthesis Examples 2 to 6 in Table 1 below.

[0134]

[0135] The structural formulas and weight average molecular weights of the resulting polymers (S1) to (S6) are shown below.

[0136]

[0137] Comparative Synthesis Examples 1 and 2 Comparative polymers (SS1) and (SS2) were synthesized under the conditions shown in Comparative Synthesis Examples 1 and 2 in Table 2 below, in the same manner as in Synthesis Example 1. However, after the reaction was stopped, (SS2) could not be reprecipitated in a methanol / water mixed solvent (E2).

[0138]

[0139] The structural formula and weight average molecular weight of the obtained polymer (SS1) are shown below: The structural formula of (SS2) is shown below.

[0140]

[0141] Examples 1 to 6, Comparative Example 1 (2) Preparation of Resist Underlayer Films Polymers (S1) to (S6), polymer (SS1), crosslinking agent (CL1), acid generator (Ad1), solvents [propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME)], and Megafac (registered trademark) R-40 (manufactured by DIC Corporation, G1) as a surfactant were mixed in the weight proportions shown in Table 3 below (the weight proportions of the crosslinking agent, acid generator, and surfactant are shown when the weight of the polymer is taken as 100 parts by weight; for the solvents, the weight proportions of each solvent are shown when the total solvent weight is taken as 100% by weight, independent of the weight of the polymer), and the mixture was filtered through a 0.1 μm polytetrafluoroethylene microfilter to prepare compositions for forming resist underlayer films.

[0142] The structural formulae of the crosslinking agent (CL1) and the acid generator (Ad1) are shown below.

[0143]

[0144]

[0145] [Measurement of Optical Constants] Each of the resist underlayer film-forming compositions prepared in Examples 1 to 6 and Comparative Example 1 was applied onto a silicon wafer using a spinner. The resist underlayer film was then baked on a hot plate at 240°C for 60 seconds to form a resist underlayer film (film thickness 50 nm). The optical constants of these resist underlayer films were measured using a spectroscopic ellipsometer, including the refractive index (n value) and optical extinction coefficient (k value, also called the attenuation coefficient) at a wavelength of 193 nm. The results are shown in Table 4.

[0146]

[0147] [Hardness Measurement] Each of the resist underlayer film-forming compositions prepared in Examples 1 to 6 and Comparative Example 1 was applied to a silicon wafer using a spinner. The resist underlayer film was then baked on a hot plate at 240°C for 60 seconds to form a resist underlayer film (film thickness: 0.2 µm). The elastic modulus and hardness of this resist underlayer film were evaluated using a thin film mechanical property evaluation device (NanoIndentor G200, manufactured by Agilent Technologies). The results are shown in Table 5.

[0148]

[0149] As described above, it was confirmed that the introduction of an aromatic aldehyde having a thermal crosslinking moiety as in Examples 1 to 6 increases the crosslinking density and makes it possible to increase the hardness of the resist underlayer film.

[0150] [Measurement of Film Density] Each of the resist underlayer film-forming compositions prepared in Examples 1 to 6 and Comparative Example 1 was applied onto a silicon wafer using a spinner. The composition was then baked on a hot plate at 240°C for 60 seconds to form a resist underlayer film (film thickness: 0.2 µm). XRR measurement was performed using an X-ray diffractometer (D8 DISCOVER, manufactured by Bruker AXS) to measure the film density of the resist underlayer film. The results are shown in Table 6.

[0151]

[0152] As described above, it was confirmed that the introduction of an aromatic aldehyde having a thermal crosslinking moiety as in Examples 1 to 6 increases the crosslink density, thereby enabling the film density of the resist underlayer film to be increased.

Claims

1. A composition for forming a resist underlayer film, comprising: a resin (G) having a plurality of composite unit structures; and a solvent; wherein the composite unit structures include a unit structure (A) having a naphthalene ring having one or two phenolic hydroxyl groups; and a unit structure (B) having one or more carbon atoms; the resin (G) is a resin obtained by a reaction to form a covalent bond between a carbon atom constituting the naphthalene ring of the unit structure (A) and a carbon atom in the unit structure (B); the first composite unit structure includes a unit structure (B-I) having a naphthalene ring as the unit structure (B); and the second composite unit structure includes a unit structure (B-II) having a benzene ring as the unit structure (B).

2. The composition for forming a resist underlayer film according to claim 1, wherein the first composite unit structure is represented by the following formula (1), and the second composite unit structure is represented by the following formula (2). (In formula (1), n1 represents 1 or 2.) (In formula (2), n2 represents 1 or 2; R represents a hydroxy group or an alkoxy group having 1 to 6 carbon atoms; m represents an integer of 1 to 5; and when m is 2 or greater, R may be different from or the same as each other.) 3. The composition for forming a resist underlayer film according to claim 1, wherein the molar ratio of the unit structure (BI) to the unit structure (B-II) in the resin (G) is 20:80 to 80:

20.

4. The composition for forming a resist underlayer film according to claim 1, wherein the resin (G) is a resin synthesized from reaction raw materials including hydroxynaphthalene having one or two phenolic hydroxyl groups, naphthaldehyde, and a benzaldehyde derivative, and in the benzaldehyde derivative, at least one hydrogen atom bonded to a carbon atom constituting a benzene ring of the benzaldehyde is substituted with a hydroxy group or an alkoxy group having 1 to 6 carbon atoms.

5. The composition for forming a resist underlayer film according to claim 1, wherein the solvent contains a solvent having a boiling point of 160°C or higher.

6. The composition for forming a resist underlayer film according to claim 1, further comprising at least one selected from the group consisting of acids and their salts, and acid generators.

7. The composition for forming a resist underlayer film according to claim 1, further comprising a crosslinking agent.

8. The composition for forming a resist underlayer film according to claim 7, wherein the crosslinking agent is at least one selected from the group consisting of aminoplast crosslinking agents and phenoplast crosslinking agents.

9. The composition for forming a resist underlayer film according to claim 1, further comprising a surfactant.

10. A resist underlayer film on a semiconductor substrate, which is a cured product of the composition for forming a resist underlayer film according to any one of claims 1 to 9.

11. A method for forming a resist pattern used in the manufacture of semiconductors, comprising the step of applying the composition for forming a resist underlayer film according to any one of claims 1 to 9 onto a semiconductor substrate and baking the composition to form a resist underlayer film.

12. A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using a composition for forming a resist underlayer film according to any one of claims 1 to 9; forming a resist film on the resist underlayer film; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the resist underlayer film through the resist pattern to form a patterned resist underlayer film; and processing a semiconductor substrate through the patterned resist underlayer film.

13. A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using a composition for forming a resist underlayer film according to any one of claims 1 to 9; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and processing a semiconductor substrate through the patterned resist underlayer film.

14. A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using a composition for forming a resist underlayer film according to any one of claims 1 to 9; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; and processing a semiconductor substrate through the patterned resist underlayer film.

15. A method for manufacturing a semiconductor device, comprising: forming a resist underlayer film on a semiconductor substrate using a composition for forming a resist underlayer film according to any one of claims 1 to 9; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern by irradiating the resist film with light or an electron beam and developing it; etching the hard mask through the resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; removing the hard mask; forming a vapor-deposited film on the resist underlayer film after removing the hard mask; processing the vapor-deposited film by etching; removing the patterned resist underlayer film to leave a patterned vapor-deposited film; and processing a semiconductor substrate through the patterned vapor-deposited film.

16. The method for manufacturing a semiconductor device according to claim 13, wherein the hard mask is formed by coating a composition containing an inorganic substance or by vapor deposition of an inorganic substance.

17. The method for manufacturing a semiconductor device according to claim 12, wherein the resist film is patterned by a nanoimprint method or a self-assembled film.

18. The method for manufacturing a semiconductor device according to claim 14, wherein the hard mask is removed by either etching or an alkaline chemical solution.

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