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

Abstract

Provided is a composition for forming a resist underlayer film, comprising: a resin (G) having a composite unit structure and represented by a specific formula (AB); and a solvent. More specifically, the composite unit structure has a unit structure (A) having an aromatic ring and a unit structure (B) having a methoxymethyl group. The unit structure (A) has at least two hydroxy groups bonded to the aromatic ring.

Description

Composition for forming a resist underlayer film, resist underlayer film, method for forming a resist pattern, and method for manufacturing a 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 advanced rapidly, and consequently, there is 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 not only reflection suppression function (having excellent optical constants to suppress reflection) but also etching resistance.

[0003] U.S. Patent Application Publication No. 2016 / 311975 Specification International Publication No. 2018 / 198960 Brochure JP 2021-81686 JP 2020-105513 International Publication No. 2013 / 146670 Brochure JP 2016-151024

[0004] For example, it is extremely difficult to produce a material that simultaneously satisfies multiple requirements such as curability, heat resistance, reduction of sublimation volume, in-plane uniformity of film thickness, etching resistance, and planarization, and there is still room for improvement as a material. Furthermore, when high-carbon materials are etched, the material bends. For this reason, high film hardness is important in order to obtain a film that does not bend easily even after etching. The present invention has been made in view of the above circumstances, and aims to provide a resist underlayer film formation composition that has excellent optical constants for suppressing reflection and can further increase film hardness, as well as a resist underlayer film formation method, a resist pattern formation method, and a semiconductor device manufacturing method using the resist underlayer film formation composition.

[0005] The inventors of the present invention conducted diligent research to solve the above problems and, as a result, found that they could solve the above problems, and completed the present invention having the following gist.

[0006] In other words, the present invention encompasses the following aspects: [1] A composition for forming a resist underlayer film, comprising a resin (G) having a composite unit structure and a solvent, wherein the resin (G) is represented by the following formula (AB), and the composite unit structure comprises: a unit structure (A) having an aromatic ring, and a unit structure (B) having a methoxymethyl group, wherein the unit structure (A) has at least two hydroxyl groups bonded to the aromatic ring. (In formula (AB), A represents unit structure (A), and B represents unit structure (B).) [2] The resist underlayer film forming composition according to [1], wherein the unit structure (B) is derived from a compound represented by the following formula (1). (In formula (1), R independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a methoxyisopropyl group, and at least one of the four Rs is a methyl group.) [3] The unit structure (A) has an aromatic ring skeleton having two or more hydroxyl groups bonded to an aromatic ring, and the aromatic ring skeleton comprises at least one skeleton represented by the following formulas (A-4-1), (A-4-2), (A-4-3), (A-4-4), (A-4-5), (A-4-6), (A-4-7), (A-4-8), (A-4-9), (A-5a), (A-5b), (A-5c), (A-5d), and (A-6a) in the resist underlayer film forming composition according to [1] or [2]. (In the formula, n1, n2, n4, n5, n6, and n9 each independently represent an integer between 2 and 4. n3a, n3b, n7a, n7b, n8a, and n8b each independently represent an integer between 0 and 4. However, the sum of n3a and n3b ​​is 2 or greater, the sum of n7a and n7b is 2 or greater, and the sum of n8a and n8b is 2 or greater.) (In the formula, Ar ４１ Each of these independently represents a residue of an aromatic ring. k1 and k2 each independently represent an integer of 1 or 2. １ is -O-, -CO-, -S-, -SO ２ - Represents an alkylene group which may be substituted with a halogen atom. When k1 is 1, X２１ represents a single bond, -O-, -CO-, -S-, -SO ２ -, or an alkylene group optionally substituted with a halogen atom. When k2 is 1, X ２２ represents a single bond, -O-, -CO-, -S-, -SO ２ -, or an alkylene group optionally substituted with a halogen atom. When k1 is 2, X ２１ represents a trivalent saturated hydrocarbon group optionally substituted with a halogen atom. When k2 is 2, X ２２ represents a trivalent saturated hydrocarbon group optionally substituted with a halogen atom. Y １ represents a trivalent saturated hydrocarbon group. Y ２ represents a tetravalent saturated hydrocarbon group. m1 and m2 each independently represent an integer of 0 to 3, provided that the sum of m1 and m2 is 2 or more. m3 to m5 each independently represent an integer of 0 to 3, provided that the sum of m3 to m5 is 2 or more. m6 to m8 each independently represent an integer of 0 to 3, provided that the sum of m6 to m8 is 2 or more. m9 to m12 each independently represent an integer of 0 to 3, provided that the sum of m9 to m12 is 2 or more.) (wherein Ar ５１Each of the following independently represents an aromatic ring residue. Each of the following independently represents an integer from 1 to 4.) [4] The resist underlayer film forming composition according to any one of [1] to [3], wherein the resin (G) is a resin synthesized by polymerizing a compound having an aromatic ring skeleton having two or more hydroxyl groups bonded to an aromatic ring and a compound having a methoxymethyl group in the presence of an acid catalyst. [5] The resist underlayer film forming composition according to any one of [1] to [4], wherein the solvent comprises a solvent with a boiling point of 160°C or higher. [6] The resist underlayer film forming composition 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 resist underlayer film forming composition according to any one of [1] to [6], further comprising a crosslinking agent. [8] The resist underlayer film forming composition 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] A resist underlayer forming composition according to any one of [1] to [8], further comprising a surfactant.

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

[11] A method for forming a resist pattern used in the manufacture of a semiconductor, comprising the step of applying the resist underlayer forming composition according to any one of [1] to [9] onto a semiconductor substrate and firing it to form a resist underlayer.

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

[13] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film forming composition 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 the semiconductor substrate through the patterned resist underlayer film.

[14] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film forming composition 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 the 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 a resist underlayer film forming composition 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 removal of 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 the semiconductor substrate through the patterned vapor-deposited film.

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

[13] to

[15] , wherein the hard mask is formed by coating a composition containing an inorganic substance or by vapor deposition of an inorganic substance.

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

[12] to

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

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

[14] or

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

[0007] According to the present invention, it is possible to provide a resist underlayer film formation composition having excellent optical constants for suppressing reflection and for further increasing film hardness, as well as a resist underlayer film formation method, a resist pattern formation method, and a semiconductor device manufacturing method using the resist underlayer film formation composition.

[0008] [Composition for forming a resist underlayer film] The resist underlayer film formation composition of the present invention comprises a resin (G) having a composite unit structure and a solvent. The resist underlayer film formation composition may further optionally contain a crosslinking agent, an acid generator, or a surfactant. Details of each component are described below.

[0009] [I. Definitions of Terms] In this specification, the definitions of the main terms relating to resin (G), which is one aspect of the present invention, are described below. Unless otherwise specified, the following definitions of terms apply to resin (G).

[0010] (I-2) "Residue" A "residue" refers to an organic group in which a hydrogen atom bonded to a carbon atom or heteroatom (such as a nitrogen atom, oxygen atom, or sulfur atom) is replaced by a bonding position. It may be a monovalent or polyvalent group. For example, replacing one hydrogen atom with one bonding position results in a monovalent organic group, while replacing two hydrogen atoms with bonding positions results in a divalent organic group.

[0011] (I-3) "Aromatic Ring" (Aromatic Group, Aryl Group, Arylene Group) The term "aromatic ring" is a concept that encompasses aromatic hydrocarbon rings, aromatic heterocycles, and their residues [sometimes called "aromatic group," "aryl group" (in the case of a monovalent group), or "arylene group" (in the case of a divalent group)], and includes not only monocyclic (aromatic monocyclic) but also polycyclic (aromatic polycyclic). In the case of a polycyclic, at least one monocycle is an aromatic monocycle, but the remaining monocycles that form a fused ring with the aromatic monocycle may be monocyclic heterocycles (heteromonocycles) or monocyclic alicyclic hydrocarbons (alicyclic monocycles). In this specification, heteroaryl groups are included in aryl groups. Heteroarylene groups are included in arylene groups.

[0012] Aromatic rings include aromatic hydrocarbon rings such as benzene, indene, naphthalene, azulene, styrene, toluene, xylene, mesitylene, cumene, anthracene, phenanthrene, triphenylene, benzoanthracene, pyrene, chrysene, fluorene, biphenyl, corannellene, perylene, fluorantene, benzo[k]fluorantene, benzo[b]fluorantene, benzo[gh]perylene, coronene, dibenzo[g,p]chrysene, acenaphthylene, acenaphthene, naphthacene, pentacene, cyclooctatetraene, and more typically aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and pyrene; and furan, pyran, pyridine, pyrimidine, pyrazine, thiophene, pyro Aromatic heterocyclic compounds such as furan, thiophene, pyrrole, N-alkylpyrrole, N-arylpyrrole, imidazole, pyridine, pyrimidine, pyrazine, triazine, thiazole, indole, phenylindole, bisindolefluorene, bisindolebenzofluorene, bisindoledibenzofluorene, purine, quinoline, isoquinoline, chromene, thiantrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, and indolocarbazole are examples, but are not limited to these.

[0013] Aromatic rings (e.g., benzene rings, naphthalene rings, etc.) may optionally have substituents, but examples of such substituents include the following atoms and groups: • Halogen atoms • Saturated or unsaturated linear, branched or cyclic hydrocarbon groups (-R) which may be interrupted once or more by oxygen atoms in the hydrocarbon chain. ａ ) (including alkyl groups, alkenyl groups, and alkynyl groups (e.g., propargyl groups), and aryl groups, which may be interrupted once or more by oxygen atoms in the middle of the hydrocarbon chain.), -OR (where R is the hydrocarbon group -R) ａ (Represents:) ・Aryloxy group・-NH ２ , -NHR or -NR ２(The two Rs may be the same or different from each other), where R is the hydrocarbon group -R ａ This represents: • Hydroxyl group • Hydroxyalkyl group • Carboxy group • Formyl group • Cyano group • Nitro group • Ester group (e.g., -CO) ２ R or -OCOR, where R is the hydrocarbon group -R ａ (This represents...) ・Amide group [for example, -NHCOR, -CONHR, -NRCOR (the two Rs may be the same or different) or -CONR ２ (The two Rs may be the same or different from each other), where R is the hydrocarbon group -R ａ This represents: 】 ・Sulfonyl-containing group (e.g., -SO ２ R, where R is the hydrocarbon group -R ａ ) Or it represents a hydroxyl group -OH. ) ・Thiol group (-SH) ・Sulfide-containing group (-SR, where R is the hydrocarbon group -R) ａ (This represents...) ・Organic group containing an ether bond [R １１ -O-R １１ (R １１ Each of these 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, anthranyl group, or a pyrenyl group. ) Residues of ether compounds represented by ; for example, organic groups containing ether bonds, including methoxy, ethoxy, and phenoxy groups.

[0014] The term "aromatic ring" further includes organic groups having a fused ring of one or more aromatic rings (such as benzene, naphthalene, anthracene, and pyrene) and one or more aliphatic or heterocyclic rings. Examples of aliphatic rings include cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, cyclohexene, methylcyclohexane, methylcyclohexene, cycloheptane, and cycloheptene, while examples of heterocyclic rings include furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, pyrrolidine, piperidine, piperazine, and morpholine.

[0015] An "aromatic ring" may also be an organic group having a structure in which two or more aromatic rings are linked by a divalent linking group. Examples of divalent linking groups include alkylene groups, arylene groups, -NH-, -NHCO-, -O-, -COO-, -CO-, -S-, -SS-, and -SO ２ - are some examples. In addition, the divalent linking group may be a divalent group obtained by removing one hydrogen atom from any substituent of the aromatic ring mentioned above.

[0016] (I-4) "Heterocycle" The term "heterocycle" encompasses both aliphatic heterocycles and aromatic heterocycles, and includes not only monocyclic (heteromonocyclic) but also polycyclic (heteropolycyclic) compounds. In the case of polycyclic compounds, at least one monocycle is a heteromonocycle, but the remaining monocycles may be aromatic hydrocarbon monocycles or alicyclic monocycles. Examples of aromatic heterocycles can be found in (I-3) above. Similar to the aromatic rings in (I-3) above, they may have substituents.

[0017] (I-5) "Non-aromatic ring" (aliphatic ring) When the "non-aromatic ring" is a monocyclic ring, the "non-aromatic monocyclic ring" refers to a monocyclic hydrocarbon that does not belong to the aromatic group, and is typically a monocyclic alicyclic compound. It may also be called an aliphatic monocyclic ring (which may include aliphatic heterocyclic rings, and may contain unsaturated bonds as long as it does not belong to the aromatic compound). Similar to the aromatic ring in (I-3) above, it may have substituents.

[0018] Examples of non-aromatic monocyclic compounds (aliphatic rings, aliphatic monocyclic compounds) include cyclopropane, cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, methylcyclohexane, cyclohexene, methylcyclohexene, cycloheptane, and cycloheptene.

[0019] When the "non-aromatic ring" is polycyclic, "non-aromatic polycyclic" refers to a polycyclic hydrocarbon that does not belong to the aromatic group, and is typically a polycyclic alicyclic compound. It may also be called an aliphatic polycyclic [which may include aliphatic heterocyclics (where at least one of the monocyclic rings is an aliphatic heterocyclic ring), or it may contain unsaturated bonds as long as it does not belong to the aromatic compound]. It includes non-aromatic dicyclic, non-aromatic tricyclic, and non-aromatic tetracyclic compounds.

[0020] When "non-aromatic ring" refers to a bicyclic non-aromatic ring, it is a fused ring composed of two monocyclic hydrocarbons that do not belong to the aromatic group, and is typically a fused ring of two alicyclic compounds. In this specification, it may also be called an aliphatic bicyclic ring (which may include aliphatic heterocyclic rings, and may contain unsaturated bonds as long as they do not belong to the aromatic group). Examples of non-aromatic bicyclic rings include bicyclopentane, bicyclooctane, and bicycloheptene.

[0021] When "non-aromatic ring" refers to a tricyclic compound, it is a fused ring composed of three monocyclic hydrocarbons that do not belong to the aromatic group. Typically, it is a fused ring of three alicyclic compounds (each of which may be a heterocyclic compound, and may contain unsaturated bonds as long as they do not belong to the aromatic group). Examples of non-aromatic tricyclic compounds include tricyclooctane, tricyclononane, and tricyclodecane.

[0022] When "non-aromatic ring" refers to a tetracyclic compound, it is a fused ring composed of four monocyclic hydrocarbons that do not belong to the aromatic group. Typically, it is a fused ring of four alicyclic compounds (each of which may be a heterocyclic compound, and may contain unsaturated bonds as long as they do not belong to the aromatic group). Examples of non-aromatic tetracyclic compounds include hexadecahydropyrene.

[0023] (I-6) "Carbon atoms constituting a ring (part)" means carbon atoms constituting a hydrocarbon ring (which may be an aromatic ring, an aliphatic ring, or a heterocycle) in an unsubstituted state.

[0024] (I-7) A "hydrocarbon group" is a group formed by removing one or more hydrogen atoms from a hydrocarbon, and such hydrocarbons include saturated or unsaturated aliphatic hydrocarbons, saturated or unsaturated alicyclic hydrocarbons, and aromatic hydrocarbons.

[0025] (I-8) In the chemical structural formulas showing the unit structure of resin (G) in this specification, bonds (indicated by *) may be shown for convenience, but unless otherwise specified, such bonds can take any bondable position in the unit structure and do not limit the bond positions in the unit structure in any way.

[0026] <Resin (G)> The resin (G) contained in the resist underlayer film forming composition of the present invention has a composite unit structure. The composite unit structure has a unit structure (A) and a unit structure (B). Unit structure (A) has an aromatic ring and has at least two hydroxyl groups bonded to the aromatic ring. Unit structure (B) has a methoxymethyl group. Unit structure (B) will be described later. Resin (G) is a resin obtained by a reaction that generates a covalent bond between the carbon atoms constituting the aromatic ring of unit structure (A) and the carbon atoms in unit structure (B). It is preferable that resin (G) does not have a structure in which two unit structures (B) are linked together.

[0027] The resin (G) is represented by the following formula (AB). (In equation (AB), A represents unit structure (A), and B represents unit structure (B).)

[0028] <<Unit Structure (A)>> Unit structure (A) has an aromatic ring and at least two hydroxyl groups bonded to the aromatic ring.

[0029] The number of carbon atoms in the unit structure (A) is not particularly limited, but for example, it is 4 to 100, and preferably 4 to 50.

[0030] Preferably, such aromatic ring has 4 to 30 carbon atoms, more preferably 4 to 24 carbon atoms.

[0031] Preferably, such aromatic rings are one or more benzene rings, naphthalene rings, anthracene rings, pyrene rings; or fused rings of a benzene ring, naphthalene ring, anthracene ring, pyrene ring and a heterocycle or aliphatic ring (such as a fluorene ring, benzofluorene ring, dibenzofluorene ring, indole ring, carbazole ring, indrocarbazole ring, etc.).

[0032] The aromatic ring may optionally have substituents, but from the viewpoint of polymerization reactivity, the substituent may contain the minimum necessary amount of heteroatoms. Furthermore, two or more aromatic rings may be linked by a linking group, and the linking group may contain the minimum necessary amount of heteroatoms. Examples of heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, and the like.

[0033] The "aromatic ring" may contain at least one heteroatom selected from N, S, and O on, within, or between the rings.

[0034] Examples of heteroatoms that may be contained on the ring include nitrogen atoms in amino groups (e.g., propargylamino group) and cyano groups; oxygen atoms in oxygen-containing substituents such as formyl group, hydroxyl group, carboxyl group, alkoxy group, alkenyloxy group, alkynyloxy group (e.g., propargyloxy group), and aryloxy group; and nitrogen and oxygen atoms in oxygen-containing substituents and nitrogen-containing substituents such as nitro group. Examples of heteroatoms that may be contained within the ring include oxygen atoms in furan and xanthene, nitrogen atoms in carbazole and pyrrole, and sulfur atoms in phenothiazine. Examples of heteroatoms that may be contained in the linking group of two or more aromatic rings include -NH-, -NHCO-, -O-, -COO-, -CO-, -S-, -SS-, and -SO ２ Examples of atoms contained in the compound include nitrogen atoms, oxygen atoms, and sulfur atoms. In this specification, "atoms constituting an aromatic ring" is synonymous with "atoms contained within the ring." "Atoms bonded to an aromatic ring" refers, for example, to "atoms or groups contained on the ring that are directly bonded to the ring" and "atoms contained between rings that are directly bonded to the ring." For example, the atoms constituting a benzene ring are carbon atoms. For example, the atoms constituting a pyrrole ring are carbon atoms and nitrogen atoms. For example, the oxygen atom of the hydroxyl group in phenol is not an atom constituting an aromatic ring. For example, the oxygen atom of the hydroxyl group in phenol is an atom bonded to a benzene ring and is an atom of a group contained on a benzene ring that is directly bonded to the benzene ring.

[0035] <<<Aromatic Ring Skeleton>>> The unit structure (A) has, for example, an aromatic ring skeleton having two or more hydroxyl groups bonded to an aromatic ring.

[0036] The unit structure (A) is, for example, a residue obtained by removing two hydrogen atoms from an aromatic ring skeleton. The aromatic ring skeleton is derived, for example, from a compound having an aromatic ring used in the synthesis of resin (G). The aromatic ring skeleton is, for example, a residue obtained by removing two hydrogen atoms from a compound having an aromatic ring used in the synthesis of resin (G).

[0037] The aromatic ring skeleton may have substituents. Examples of substituents include halo groups (halogen atoms), alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, hydroxyl groups, hydroxyalkyl groups, carboxyl groups, formyl groups, cyano groups, nitro groups, ester groups, amide groups, sulfonyl-containing groups, thiol groups, sulfide-containing groups, ether-bond-containing groups, etc. Examples of alkyl groups include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms. Examples of alkenyl groups include linear, branched, or cyclic alkenyl groups having 2 to 10 carbon atoms. Examples of alkoxy groups include groups represented by -OR, where R is a saturated or unsaturated linear, branched, or cyclic hydrocarbon group (-R) which may be interrupted once or more times by an oxygen atom in the hydrocarbon chain. ａ ) represents. Examples of the number of carbon atoms in an alkoxy group include 1 to 20. Examples of aryl groups include aryl groups with 6 to 30 carbon atoms. Examples of aryloxy groups include aryloxy groups with 6 to 30 carbon atoms. Examples of amino groups include -NH ２ , -NHR or -NR ２ A group represented by the hydrocarbon group -R is an example. Here, R is the hydrocarbon group -R ａ Represents -NR ２In this, the two Rs may be the same or different. Examples of hydroxyalkyl groups include linear, branched, or cyclic hydroxyalkyl groups having 1 to 20 carbon atoms. Examples of ester groups include -CO ２ A group represented by R or -OCOR is an example. Here, R is the hydrocarbon group -R ａ This represents the amide group, which can be -NHCOR, -CONHR, -NRCOR, or -CONR. ２ A group represented by the hydrocarbon group -R is an example. Here, R is the hydrocarbon group -R ａ This represents a group, and if there are two Rs, the two Rs may be the same or different. Examples of sulfonyl-containing groups include -SO ２ A group represented by R is an example. Here, R is the hydrocarbon group -R ａ Alternatively, it represents a hydroxyl group -OH. Examples of sulfide-containing groups include groups represented by -SR, where R is the hydrocarbon group -R. ａ This represents the ether bond-containing group, R １１ -O-R １１ Examples include residues of ether compounds containing an ether bond represented by . Here, R １１ Each of these 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, 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.

[0038] Examples of the alkyl groups mentioned above include methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, and cyclopropyl group. Pentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2-dimethyl ethyl-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, 2,2Examples include 3-trimethylcyclopropyl group, 1-ethyl-2-methylcyclopropyl group, 2-ethyl-1-methylcyclopropyl group, 2-ethyl-2-methylcyclopropyl group, 2-ethyl-3-methylcyclopropyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, etc.

[0039] Examples of aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include the skeletons represented by the following formulas (A-4-1), (A-4-2), (A-4-3), (A-4-4), (A-4-5), (A-4-6), (A-4-7), (A-4-8), and (A-4-9). The aromatic rings in these skeletons may have substituents. The same applies to the following skeletons. (In the formula, n1, n2, n4, n5, n6, and n9 each independently represent an integer between 2 and 4. n3a, n3b, n7a, n7b, n8a, and n8b each independently represent an integer between 0 and 4. However, the sum of n3a and n3b ​​is 2 or greater, the sum of n7a and n7b is 2 or greater, and the sum of n8a and n8b is 2 or greater.)

[0040] Furthermore, examples of aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include the skeletons represented by the following formulas (A-5a), (A-5b), (A-5c), or (A-5d). (In the formula, Ar ４１ Each of these independently represents a residue of an aromatic ring. k1 and k2 each independently represent an integer of 1 or 2. １ is -O-, -CO-, -S-, -SO ２ - Represents an alkylene group which may be substituted with a halogen atom. When k1 is 1, X ２１ These are single bonds, -O-, -CO-, -S-, -SO ２ - Represents an alkylene group which may be substituted with a halogen atom. When k2 is 1, X ２２ These are single bonds, -O-, -CO-, -S-, -SO ２- Represents an alkylene group which may be substituted with a halogen atom. When k1 is 2, X ２１ This represents a trivalent saturated hydrocarbon group which may be substituted with a halogen atom. When k2 is 2, X ２２ This represents a trivalent saturated hydrocarbon group which may be substituted with a halogen atom. １ This represents a trivalent saturated hydrocarbon group. ２ represents a tetravalent saturated hydrocarbon group. m1 and m2 each independently represent integers from 0 to 3, provided that the sum of m1 and m2 is 2 or greater. m3 to m5 each independently represent integers from 0 to 3, provided that the sum of m3 to m5 is 2 or greater. m6 to m8 each independently represent integers from 0 to 3, provided that the sum of m6 to m8 is 2 or greater. m9 to m12 each independently represent integers from 0 to 3, provided that the sum of m9 to m12 is 2 or greater.

[0041] Ar ４１ Examples of aromatic rings in the residues of the aromatic ring include aromatic rings represented by the following formula (G3). These aromatic rings may have substituents.

[0042] X １ , and X ２ Examples of the number of carbon atoms in the alkylene group, which may be substituted with halogen atoms, include 1 to 20. Examples of the structure of the alkylene group include linear, branched, and cyclic structures, as well as combinations of two or more of these. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0043] Y １ , and Y ２ Examples of the number of carbon atoms in a saturated hydrocarbon group include 1 to 20. Examples of the structure of a saturated hydrocarbon group include linear, branched, and cyclic structures, as well as combinations of two or more of these.

[0044] Furthermore, examples of aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include the skeletons represented by the following formulas (A-6a), (A-6b-1), (A-6b-2), (A-6c), or (A-6d). (In formulas (A-6a), (A-6b-1), (A-6b-2), (A-6c), and (A-6d), Ar ５１ Each of the following independently represents a residue in an aromatic ring. Each of n11 independently represents an integer from 1 to 4. Each of the following independently represents either 0 or 1. When p is 1, the oxygen atom forms a bridging structure between aromatic rings as an ether bond; when p is 0, there is no ether bond that forms a bridging structure between aromatic rings. L represents a single bond or a divalent linking group.

[0045] Ar ５１ Examples of aromatic rings in this compound include those represented by the following formula (G1), with benzene rings and naphthalene rings being preferred. These aromatic rings may have substituents.

[0046] For example, L can be a divalent group obtained by removing two hydrogen atoms from the following structure.

[0047] n11, for example, independently represents either 1 or 2.

[0048] Furthermore, examples of aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include the skeletons represented by the following formulas (A-7a), (A-7b), or (A-7c). (In formula (A-7a), formula (A-7b), and formula (A-7c), Ar ６１ Each of these independently represents a residue in an aromatic ring. n21 independently represents an integer from 1 to 4.

[0049] Ar ６１ Examples of aromatic rings in this formula include those represented by formula (G1) above, with benzene rings and naphthalene rings being preferred. n21 independently represents, for example, 1 or 2.

[0050] Furthermore, examples of aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include the skeletons represented by the following formulas (A-8a-1), (A-8a-2), (A-8b), (A-8c), (A-8d), (A-8e), (A-8f), (A-8g-1), or (A-8g-2). (In equations (A-8a-1), (A-8b), (A-8c), (A-8e), (A-8f), (A-8g-1), and (A-8g-2), n31 independently represents an integer between 2 and 4. In equation (A-8a-2), n32 and n33 independently represent integers between 0 and 4, provided that the sum of n32 and n33 is 2 or greater. In equation (A-8d), n32 and n33 independently represent integers between 0 and 4, provided that the sum of n32 and n33 is 2 or greater. In equation (A-8b), X １ X represents -O- or -NH-. In formula (A-8d), X ２ These are -O-, -S-, or -CH ２ It represents -. In equation (A-8e), X ３ is -S-, -CH ２ It represents - or -NH-. In formula (A-8f), X ４ represents -CO- or -O-, X ５ is, -CH ２ (Represents - or -O-.)

[0051] n31, for example, independently represents 2. n32 and n33, for example, independently represent 0, 1, or 2.

[0052] Examples of skeletons represented by formulas (A-4-1) to (A-4-9) include the following. The aromatic rings in these skeletons may have substituents, and the hydrogen atoms of the hydroxyl groups may be replaced by substituents, as long as the number of hydroxyl groups in the skeleton is not less than two. The same applies to the following skeletons.

[0053] Examples of skeletons represented by formula (A-5a) include the following:

[0054] Examples of skeletons represented by formula (A-5b) include the following:

[0055] Examples of skeletons represented by formula (A-5c) include the following:

[0056] Examples of skeletons represented by formula (A-5d) include the following:

[0057] Examples of skeletons represented by formula (A-6a) include the following:

[0058] Examples of skeletons represented by formula (A-6b-1) or formula (A-6b-2) include the following:

[0059] Examples of skeletons represented by formula (A-6c) include the following:

[0060] Examples of skeletons represented by formula (A-6d) include the following:

[0061] Examples of skeletons represented by formula (A-7a), formula (A-7b), or formula (A-7c) include the following:

[0062] Examples of skeletons represented by formula (A-8a-1) or formula (A-8a-2) include the following:

[0063] Examples of skeletons represented by formula (A-8b) include the following:

[0064] Examples of skeletons represented by formula (A-8c) include the following:

[0065] Examples of skeletons represented by formula (A-8d) include the following:

[0066] Examples of skeletons represented by formula (A-8e) include the following:

[0067] Examples of skeletons represented by equation (A-8f) include the following:

[0068] Examples of skeletons represented by formula (A-8g-1) or formula (A-8g-2) include the following:

[0069] Other aromatic ring skeletons having two or more hydroxyl groups bonded to an aromatic ring include, for example, the following skeletons.

[0070] Furthermore, the H of the hydroxyl group bonded to the aromatic ring in the above-mentioned aromatic ring skeleton, and the hydrogen atom bonded to the aromatic ring in the aromatic ring skeleton, may be replaced by substituents as long as there are two or more hydroxyl groups. Examples of such substituents include substituents (S) represented by the following formulas (S1) to (S7).

[0071] (In formulas (S1) to (S7), R ｓａ R represents a monovalent non-aromatic hydrocarbon group with 1 to 10 carbon atoms. ｓｂ Each of these independently represents a single bond or a divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms. ｓｃ Each of these independently represents a divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms. ｓｄ ａｌｋｙｎｙｌ Each of these independently represents an alkynyl group with 2 to 4 carbon atoms. ｓａ Each of these independently represents a monovalent aromatic hydrocarbon group with 6 to 20 carbon atoms. ｓｂ Each of these independently represents a divalent aromatic hydrocarbon group with 6 to 20 carbon atoms. ｓａ and X ｓｂeach independently represent 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 bonding site.)

[0072] <R ｓａ > R ｓａ Examples of the monovalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms in include an alkyl group having 1 to 10 carbon atoms and a monovalent unsaturated hydrocarbon group having 2 to 10 carbon atoms. 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, all of the two or more carbon-carbon multiple bonds may 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. Two or more carbon-carbon multiple bonds may be conjugated or non-conjugated.

[0073] <R ｓｂ , and R ｓｃ > R ｓｂ , and R ｓｃ Examples of the divalent non-aromatic hydrocarbon group having 1 to 10 carbon atoms in 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, all of the two or more carbon-carbon multiple bonds may 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. Two or more carbon-carbon multiple bonds may be conjugated or non-conjugated. Examples of R ｓｂ , and R ｓｃ include the following groups. (* represents a bonding site.)

[0074] <R ｓｄａｌｋｙｎｙｌ > R ｓｄ ａｌｋｙｎｙｌ represents 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, a propargyl group (2-propynyl group), and the like.

[0075] <Ar ｓａ > Ar ｓａ The monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms in Ar is a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, perinaphthene, pyrene, fluorene, biphenyl, and the like.

[0076] <Ar ｓｂ > Ar ｓｂ The divalent aromatic hydrocarbon group having 6 to 20 carbon atoms in Ar is a residue obtained by removing two hydrogen atoms from an aromatic hydrocarbon having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, pyrene, fluorene, biphenyl, and the like.

[0077] <X ｓａ and X ｓｂ > X ｓａ and X ｓｂ Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms in X and X 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. The 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 the aromatic hydrocarbon having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, phenanthrene, perinaphthene, pyrene, fluorene, biphenyl, and the like.

[0078] Examples of the substituent represented by formula (S1) include the following groups. (* represents a bonding site.)

[0079] Examples of substituents represented by formula (S2) include the following groups. (* indicates a link.)

[0080] Examples of substituents represented by formula (S3) include the following groups. (* indicates a link.)

[0081] Examples of substituents represented by formula (S4) include the following groups. (* indicates a link.)

[0082] Examples of substituents represented by formula (S5) include the following groups. (* indicates a link.)

[0083] Examples of substituents represented by formula (S6) include the following groups. (* indicates a link.)

[0084] Examples of substituents represented by formula (S7) include the following groups. (* indicates a link.)

[0085] Other substituents include, for example, the following groups: (* indicates a link.)

[0086] The unit structure (A) is preferably at least one selected from the following. Note that the positions of the two bonds shown in each unit structure described below are for convenience only and can extend from any possible carbon atom, and do not limit their positions.

[0087] (Examples of unit structures composed of an aromatic ring skeleton having two or more hydroxyl groups attached to an aromatic ring)

[0088] <<Unit Structure (B)>> Unit structure (B) has a methoxymethyl group. In unit structure (B), the methoxymethyl group is directly bonded to an aromatic ring, for example. Unit structure (B) is preferably a unit structure derived from a compound represented by the following formula (1).

[0089] (In formula (1), each R independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a methoxyisopropyl group, and at least one of the four Rs is a methyl group.)

[0090] In formula (1), R is preferably a hydrogen atom or a methyl group, and more preferably all Rs are methyl groups. In this specification, the compound represented by formula (1) is also called a methylol compound.

[0091] The resin (G) is formed by the formation of a covalent bond (substitution reaction, addition reaction, condensation reaction, or addition-condensation reaction, etc.) between an organic compound having a functional group (e.g., a methoxymethyl group) that enables covalent bonding with an aromatic ring and an aromatic ring in a compound having an aromatic ring, in the presence of an acid catalyst or under equivalent reaction conditions.

[0092] Therefore, the resin (G) is formed by linking multiple compounds having aromatic rings, where an organic compound containing carbon atoms derived from the functional group (sometimes called a "linked carbon atom") forms a covalent bond with the aromatic ring in a compound having an aromatic ring via the linked carbon atoms.

[0093] Unit structure (B) is one or more unit structures that include linked carbon atoms bonded to the aromatic ring in unit structure (A). Unit structure (B) can link two unit structures (A) by covalent bonding with unit structure (A).

[0094] It is preferable that resin (G) does not have a structure in which two unit structures (B) are linked together. It is also preferable that resin (G) does not have a structure in which two compounds represented by formula (1) are linked together. Examples of structures in which two compounds represented by formula (1) are linked together include the following structures (I) and (II). Structure (I): A structure obtained by a reaction that generates a covalent bond between a carbon atom constituting the aromatic ring of one compound represented by formula (1) and the other compound represented by formula (1). Structure (II): A structure obtained by a condensation reaction between a hydroxyl group of one compound represented by formula (1) and the other compound represented by formula (1).

[0095] The compound represented by formula (1) can be exemplified as follows:

[0096]

[0097] Of these, the compound represented by formula (1) is preferably represented by the following formula (2).

[0098]

[0099] The composite unit structure in resin (G) may include unit structures other than unit structure (A) and unit structure (B). However, it is preferable that resin (G) does not have a structure in which two unit structures (B) are linked together.

[0100] <Preparation of Resin (G)> Resin (G) having the structure represented by formula (AB) can be prepared by known methods. For example, a cyclic compound represented by H-A-H and RO-B-OR, RO-CH ２ -B-CH ２ It can be prepared by condensing oxygen-containing compounds represented by -OR, etc. Here, A and B are the same as above. R represents a hydrogen atom, a halogen, or an alkyl group having about 1 to 4 carbon atoms.

[0101] The ring-containing compound and the oxygen-containing compound may be used individually, or two or more may be used in combination. In this condensation reaction, the oxygen-containing compound can be used in a ratio of 0.1 to 10 moles, preferably 0.1 to 2 moles, per mole of the ring-containing compound.

[0102] Examples of catalysts 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 cyclic compound (total of multiple types).

[0103] The condensation reaction can be carried out without a solvent, but it is usually carried out using a solvent. The solvent is not particularly limited as long as it can dissolve the reaction substrate and does not inhibit the reaction. Examples include 4-methyltetrahydropyran, 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. Of these solvents, 4-methyltetrahydropyran is preferred. 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.

[0104] The weight-average molecular weight of resin (G) according to one aspect of the present invention is usually 500 to 100,000, preferably 600 to 50,000, 700 to 10,000, or 800 to 8,000.

[0105] The resin (G) content in the resist underlayer film forming composition is preferably 25 to 100% by mass, more preferably 50 to 100% by mass, and even more preferably 70 to 100% by mass, relative to the mass of the film-forming component. Here, the film-forming component refers to the component obtained by removing the solvent component from the resist underlayer film forming composition.

[0106] The molar ratio ((A):(B)) of unit structure (A) to unit structure (B) in resin (G) is preferably 30:70 to 50:50, more preferably 40:60 to 50:50, and even more preferably 50:55 to 50:50. The molar ratio of unit structure (A) to unit structure (B) in resin (G) can also be expressed as the molar ratio of compound (A) that is the raw material for unit structure (A) to compound (B) that is the raw material for unit structure (B). The molar ratio ((A):(B)) of compound (A) to compound (B) is preferably 30:70 to 50:50, more preferably 40:60 to 50:50, and even more preferably 50:55 to 50:50. Here, compound (A) may be one type or two or more types. Similarly, compound (B) may be one type or two or more types.

[0107] <Solvent> A composition for forming a resist underlayer film, which is one aspect of the present invention, contains a solvent.

[0108] The solvent is not particularly limited as long as it can dissolve the resin (G) and any other optional components that may be added as needed.

[0109] Examples of solvents 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, and tol Ethylene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyethyl acetate, ethyl hydroxyethyl acetate, 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 mono Propyl 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 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,Examples of solvents include isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, methyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyethyl, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used individually or in combination of two or more.

[0110] Furthermore, solvents with a boiling point of 160°C or higher can be included in combination with solvents with a boiling point of less than 160°C.

[0111] As such high-boiling point solvents, for example, the following compounds described in International Publication No. 2018 / 131562 (A1) can be preferably used.

[0112] [R in equation (i)] １ , R ２ and R ３ Each represents 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. These atoms may be the same or different, and may be bonded to each other to form a ring structure. Alternatively, 1,6-diacetoxyhexane (boiling point 260°C), tripropylene glycol monomethyl ether (boiling point 242°C), and various other high-boiling point solvents described in paragraph 0082 of Japanese Patent Publication No. 2021-84974 can be preferably used.

[0113] Alternatively, as described in Japanese Patent Publication No. 2019-20701, 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 mo Various high-boiling point solvents described in paragraphs 0023 to 0031 of the published patent can be preferably used, including methyl 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 others.

[0114] A composition for forming a resist underlayer film, according to one aspect of the present invention, may contain an acid and / or a salt thereof and / or an acid generator.

[0115] Examples of acids 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.

[0116] As the salt, the aforementioned acid salts can also be used. While not limited to these, ammonia derivative salts such as trimethylamine salt and triethylamine salt, pyridine derivative salts, and morpholine derivative salts can be suitably used.

[0117] Only one type of acid and / or its salt may be used, or two or more types may be used in combination. The amount added is usually 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 5% by mass, relative to the total solids.

[0118] Examples of acid generators include thermal acid generators and photoacid generators.

[0119] Examples of thermal acid generators include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE® CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG2689, TAG2700 (manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), and other alkyl organic sulfonates.

[0120] The photoacid generator produces acid when the resist is exposed to light. Therefore, the acidity of the underlying film can be adjusted. This is one method for matching the acidity of the underlying film to that of the upper resist. Furthermore, adjusting the acidity of the underlying film allows for adjustment of the pattern shape of the resist formed on the upper layer.

[0121] Examples of photoacid generators included in the resist underlayer film forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyl diazomethane compounds.

[0122] Examples of iodonium salt compounds include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoron-butanesulfonate, diphenyliodonium perfluoron-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 nonafluoron-butanesulfonate, triphenylsulfonium camphorsulfonate and triphenylsulfonium trifluoromethanesulfonate.

[0123] Examples of sulfonimide compounds include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoron-butanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0124] Examples of disulfonyl diazomethane compounds include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0125] Only one type of acid generator may be used, or two or more types may be used in combination.

[0126] If an acid generator is used, the ratio is 0.01 to 10 parts by mass, or 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass, per 100 parts by mass of solid content of the resist underlayer film forming composition.

[0127] A resist underlayer film forming composition according to one aspect of the present invention may optionally contain, in addition to the above, a crosslinking agent, a surfactant, a photoabsorbent, a rheology modifier, an adhesion aid, and the like.

[0128] Typical crosslinking agents include aminoplast crosslinking agents and phenoplast crosslinking agents.

[0129] As the crosslinking agent, a crosslinking agent with high heat resistance can be used. Preferably, a crosslinking agent with high heat resistance is a compound containing a crosslinking substituent having an aromatic ring (e.g., a benzene ring, a naphthalene ring) in its molecule.

[0130] Examples of aminoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluryl, urea, and polymers thereof. Preferably, the crosslinking agent has at least two crosslinking substituents and is a compound such as methoxymethylated glycoluryl, butoxymethylated glycoluryl, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensed products of these compounds can also be used.

[0131] Preferably, it is at least one selected from the group consisting of tetramethoxymethylglycoluryl and hexamethoxymethylmelamine.

[0132] Here are a few specific examples:

[0133]

[0134] Examples of phenoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatics and polymers thereof. Preferably, the crosslinking agent has at least two crosslinking substituents in one molecule, and is a compound 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, or α,α-bis(4-hydroxy-2,5-dimethylphenyl)-4-formyltoluene. Condensates of these compounds can also be used.

[0135] Examples of such compounds include compounds having the substructure of formula (4) below, and polymers or oligomers having the repeating unit of formula (5) below.

[0136] The above R １１ , R １２ , R １３ , and R １４ n1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl groups described above can be used. n1 is an integer from 1 to 4, n2 is an integer from 1 to (5-n1), and (n1+n2) is an integer from 2 to 5. n3 is an integer from 1 to 4, n4 is from 0 to (4-n3), and (n3+n4) is an integer from 1 to 4. The oligomers and polymers can be used with a number of repeating unit structures ranging from 2 to 100, or from 2 to 50.

[0137] Here are a few specific examples:

[0138]

[0139]

[0140]

[0141]

[0142] Crosslinking agents such as aminoplast crosslinking agents and phenoplast crosslinking agents may be used individually or in combination of two or more. Aminoplast crosslinking agents can be manufactured by known methods or similar methods, or commercially available products may be used.

[0143] Furthermore, the amount of crosslinking agent used, such as aminoplast crosslinking agent or phenoplast crosslinking agent, varies depending on the coating solvent used, the substrate used, the required solution viscosity, the required film shape, etc., but is 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.5% by mass or more, or 1.0% by mass or more, relative to the total solid content of the resist underlayer film forming composition according to the present invention, and is 80% by mass or less, 50% by mass or less, 40% by mass or less, 20% by mass or less, or 10% by mass or less.

[0144] The resist underlayer film forming composition according to the present invention does not produce pinholes or striations, and a surfactant may be added to further improve the coatability against surface unevenness.

[0145] 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 octyl phenol ether and polyoxyethylene nonyl phenol 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 include fluorine-based surfactants such as Eftop EF301, EF303, EF352 (manufactured by Tochem Products Co., Ltd., product names), Megafac F171, F173, R-30, R-40 (manufactured by Dainippon Ink, Inc., product names), Florard FC430, FC431 (manufactured by Sumitomo 3M Limited, product names), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd., product names), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0146] The amount of these surfactants added is usually 2.0% by mass or less, preferably 1.0% by mass or less, relative to the total solid content of the resist underlayer film forming composition according to the present invention. These surfactants may be added individually or in combination of two or more types.

[0147] Examples of light absorbers include commercially available light absorbers listed in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Synthetic Organic 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. DisperseRed 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199 and 210; C. I. DisperseViolet 43; C. I. DisperseBlue 96; C. I. Fluorescent Brightening Agent 112, 135 and 163; C. I. SolventOrange 2 and 45; C. I. SolventRed 1, 3, 8, 23, 24, 25, 27 and 49; C. I. PigmentGreen 10; C. I. Pigment Brown 2 and others can be suitably used. The above light absorber is usually blended in a proportion of 10% by mass or less, preferably 5% by mass or less, relative to the total solid content of the resist underlayer film forming composition according to the present invention.

[0148] Rheology modifiers are added primarily to improve the fluidity of the resist underlayer film formation composition, and particularly in the baking process, to improve the uniformity of the resist underlayer film thickness and the filling of holes by the resist underlayer film formation composition. Specific examples include phthalate derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as dinormal butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di(n-butyl) malate, diethyl malate, and dinonyl malate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; or stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically blended in a proportion of less than 30% by mass relative to the total solid content of the resist underlayer film formation composition according to the present invention.

[0149] Adhesion aids are added primarily to improve the adhesion between the substrate or resist and the resist underlayer film forming composition, and especially to prevent the resist from peeling off 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; and vinyltrichlorosilane. Examples of adhesive aids include silanes such as ran, 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 adhesive aids are typically blended in a proportion of less than 5% by mass, preferably less than 2% by mass, relative to the total solid content of the resist underlayer film forming composition according to the present invention.

[0150] The solid content of the resist underlayer film forming composition according to the present invention is 0.1 to 70% by mass, or 0.1 to 60% by mass. The solid content is the proportion of all components in the resist underlayer film forming composition excluding the solvent. The solid content may contain a crosslinkable resin in a proportion 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.

[0151] [Resist Underlayer Film] The resist underlayer film can be formed, for example, as follows, using the resist underlayer film forming composition according to the present invention.

[0152] Substrates used in the manufacture of semiconductor devices (e.g., silicon wafer substrates, silicon dioxide coated substrates (SiO ２ A resist underlayer film forming composition according to one embodiment of the present invention is applied to a substrate (such as a glass substrate, silicon nitride substrate (SiN substrate), silicon oxide nitride substrate (SiON substrate), titanium nitride substrate (TiN substrate), tungsten substrate (W substrate), glass substrate, ITO substrate, polyimide substrate, and low dielectric constant material (low-k material) coated substrate, etc.) using an appropriate coating method such as a spinner or coater, and then fired using a heating means such as a hot plate to form a resist underlayer film. The firing conditions are appropriately selected from a firing temperature of 80°C to 800°C and a firing time of 0.3 to 60 minutes. Preferably, the firing temperature is 150°C to 500°C and the firing time is 0.5 to 2 minutes. Air may be used as the atmospheric gas during firing, or an inert gas such as nitrogen or argon may be used. In one embodiment, it is particularly preferable that the oxygen concentration is 1% or less. The thickness of the underlying film formed here can be, 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 (mold replica) of the quartz imprint mold can be fabricated.

[0153] Furthermore, according to one aspect of the present invention, 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 on the resist underlayer film by coating or vapor deposition. For example, in addition to the method of forming the adhesion layer described in Japanese Patent Application Publication No. 2013-202982 and Japanese Patent No. 5827180, or the silicon-containing resist underlayer film (inorganic resist underlayer film) formation composition described in International Publication No. 2009 / 104552 (A1) by spin coating, a Si-based inorganic material film can be formed by CVD or the like.

[0154] Furthermore, by applying a resist underlayer film forming composition, which is one aspect of the present invention, to a semiconductor substrate having stepped portions and portions without steps (a so-called stepped substrate) and firing it, the step difference between the stepped portions and the portions without steps can be reduced.

[0155] [Method for forming a resist pattern] The method for forming a resist pattern of the present invention includes at least the step of applying the resist underlayer film forming composition of the present invention onto a semiconductor substrate and firing it to form a resist underlayer film. The method for forming a resist pattern of the present invention may also include the following steps: - A step of forming a resist film on the resist underlayer film. - A step of irradiating the resist film with light or an electron beam, then developing the resist film to obtain a resist pattern. and - A step of etching the resist underlayer film using the resist pattern as a mask.

[0156] [Method for Manufacturing a Semiconductor Device] (i) A method for manufacturing a semiconductor device according to one 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 according to one aspect of the present invention; 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 the semiconductor substrate through the patterned resist underlayer film.

[0157] (ii) A method for manufacturing a semiconductor device according to one 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 according to one 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 the semiconductor substrate through the patterned resist underlayer film.

[0158] (iii) Furthermore, a method for manufacturing a semiconductor device according to one 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 according to one 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.

[0159] (iv) A method for manufacturing a semiconductor device according to one 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 according to one 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; forming a vapor-deposited film (spacer) on the resist underlayer film after the hard mask has been removed; processing the vapor-deposited film (spacer) by etching; removing the patterned resist underlayer film and leaving the patterned vapor-deposited film (spacer); and processing the semiconductor substrate through the patterned vapor-deposited film (spacer).

[0160] The semiconductor substrate can be processed using the manufacturing methods described in (i) to (iv) above.

[0161] The step of forming a resist underlayer film using a resist underlayer film formation composition according to one aspect of the present invention is as described above in [Resist Underlayer Film].

[0162] A hard mask, such as a silicon-containing film, may be formed as a second resist underlayer on the resist underlayer formed by the above process, and a resist pattern may be formed thereon [as described in (ii) to (iv)].

[0163] The hard mask may be a coated film of inorganic material, or a vapor-deposited film of inorganic material formed by vapor deposition methods such as CVD or PVD, or a SiO film, SiN film, or SiO ２ A membrane can be used as an example.

[0164] Furthermore, an anti-reflective coating (BARC) may be formed on this hard mask, or a resist shape correction film that does not have anti-reflective properties may be formed.

[0165] In the process of forming the resist pattern, exposure is performed either through a mask (reticle) for forming a predetermined pattern or by direct drawing. For example, g-line, i-line, KrF excimer laser, ArF excimer laser, EUV, and electron beams can be used as exposure sources. After exposure, post-exposure baking is performed as needed. Then, the resist is developed with a developer (e.g., 2.38% by mass aqueous solution of tetramethylammonium hydroxide, butyl acetate), and further rinsed with a rinse solution or pure water to remove the used developer. Finally, post-baking is performed to dry the resist pattern and improve its adhesion to the substrate.

[0166] The etching process performed after the formation of the resist pattern is carried out by dry etching.

[0167] Furthermore, the following gases are used for processing the hard mask (silicon-containing layer), resist underlayer film, and substrate: CF ４ CHF ３ ,CH ２ F ２ CH ３ F, C ４ F ６ , C ４ F ８ , O ２ , N ２ O, NO ２ , H ２He can be used. These gases may be used alone or in mixtures of two or more gases. Furthermore, these gases may be mixed with argon, nitrogen, carbon dioxide, carbonyl sulfide, sulfur dioxide, neon, or nitrogen trifluoride.

[0168] The resist film may be patterned by a nanoimprint method or a self-assembled film method.

[0169] In nanoimprint lithography, the resist composition is formed using a patterned mold that is transparent to irradiated light. In contrast, self-assembled film lithography uses self-assembled films, such as diblock polymers (e.g., polystyrene-polymethyl methacrylate), which naturally form ordered structures on the nanometer scale, to create patterns.

[0170] In the nanoimprint method, before applying the curable composition that will become the resist film, a silicon-containing layer (hard mask layer) may be optionally formed on the resist underlayer by coating or vapor deposition, and an adhesion layer may be further formed on the resist underlayer or the silicon-containing layer (hard mask layer) by coating or vapor deposition, and the curable composition that will become the resist film may be applied on the adhesion layer.

[0171] Furthermore, wet etching may be performed to simplify the process steps and reduce damage to the processed substrate. This helps to suppress variations in processed dimensions and a reduction in pattern roughness, making it possible to process the substrate with a high yield. For this reason, in (iii) to (iv) above, the hard mask can be removed by either etching or an alkaline chemical solution. In particular, when using an alkaline chemical solution, there are no restrictions on the components, but it is preferable that the alkaline components include the following.

[0172] Examples of alkaline components 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 Examples include 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, from the viewpoint of handling, tetramethylammonium hydroxide and tetraethylammonium hydroxide are particularly preferred, and an inorganic base may be used in combination with a quaternary ammonium hydroxide. As inorganic bases, alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and rubidium hydroxide are preferred, with potassium hydroxide being more preferred.

[0173] The present invention will be described in more detail below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the examples described below.

[0174] The weight-average molecular weight Mw of the resins shown in Synthesis Examples 1 to 12 below was obtained by gel permeation chromatography (hereinafter abbreviated as GPC). A GPC instrument manufactured by Tosoh Corporation was used for the measurement, and the measurement conditions were as follows: GPC column: TSKgel Super-MultiporeHZ-N (2 columns) Column temperature: 40°C Solvent: Tetrahydrofuran (THF) Flow rate: 0.35 ml / min Standard sample: Polystyrene (manufactured by Tosoh Corporation)

[0175] [Synthesis of Resins] The resins (P1) to (P12) used for the resist underlayer film were synthesized using compound group A, compound group B, compound group C, catalyst group D, and solvent group E as shown below. Compound group A is a compound that gives the unit structure (B) of this application, and compound group B is a compound that gives the unit structure (A) of this application.

[0176] (Compound groups A to C)

[0177] (Catalyst group D, Solvent group E) Methanesulfonic acid: D1 4-methyltetrahydropyran (=MTHP): E1 Propylene glycol monomethyl ether (=PGME): E2 Ultrapure water (=DIW): E3 Propylene glycol monomethyl ether acetate (=PGMEA): E4

[0178] [Synthesis Example 1] The details of Synthesis Example 1 are as follows. 15.0 g of A1, 7.7 g of B1, and 136.4 g of E1 were placed in a flask, and the temperature inside the flask was raised to approximately 90°C. Then, a solution of 1.0 g of D1 diluted with 10.4 g of E1 was added dropwise. After the addition was complete, the mixture was allowed to react for 26 hours. After the reaction was completed and the mixture was allowed to cool to room temperature, liquid-liquid purification using E3 was performed three times. The organic layer was then collected, concentrated in a flask with E4, and the solvent was replaced. The weight-average molecular weight (Mw) measured in polystyrene equivalent by GPC was approximately 3,700.

[0179] [Synthesis Examples 2-12] Synthesis Examples 2-12 were carried out using the corresponding raw materials and solvents, following the same procedure as in Synthesis Example 1. The amount of compound added, reaction time, and purification solvent used for each resin are shown in Table 1 below.

[0180]

[0181] The structural formulas of the obtained resins (P1) to (P12) are shown below. In the formulas, n represents the number of repeating units.

[0182]

[0183] [Preparation of Compositions for Forming a Resist Underlayer Film] Resins (P1) to (P12), a crosslinking agent (CL1), an acid generator (Ad1) consisting of TAG2689 (manufactured by King Industries), and solvents (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME)) were mixed in the proportions shown in Table 2 below and filtered through a 0.1 μm polytetrafluoroethylene microfilter to prepare compositions for forming a resist underlayer film (M1 to M12). The values ​​shown in Table 2 represent the mass ratios of the crosslinking agent and acid generator when the mass of the resin is 100 parts, and for the solvents, the values ​​represent the mass ratios of each solvent when the total mass of the solvent is 100% by mass, independently of the mass of the resin.

[0184] The structural formula of the crosslinking agent (CL1) is shown below.

[0185]

[0186]

[0187] [Examples 1-7, Comparative Examples 1-5] [Solvent Resistance Test to Resist Solvents] The resist underlayer film formation compositions of Examples 1-7 and Comparative Examples 1-5 were applied onto a silicon wafer using a spin coater and fired in air at the predetermined temperature and time shown in Table 3 to form a resist underlayer film with a thickness of approximately 50 nm. The formed resist underlayer film was immersed in a general-purpose thinner, a PGME / PGMEA mixed solution (mass ratio = 7 / 3), for 60 seconds, then spin-dried and fired at 100°C for 30 seconds. The solvent resistance was confirmed by comparing the film thickness before and after thinner immersion. A reduction in film thickness of 5% or less before and after thinner immersion was judged as "○", and a reduction of more than 5% was judged as "×". The results are shown in Table 3. Samples judged as "○" are considered to have sufficient curability to be used as a resist underlayer film.

[0188]

[0189] [Hardness of the Resist Underlayer Film] The resist underlayer film formation compositions of Examples 1-7 and Comparative Examples 1-5 were applied onto silicon wafers using a spin coater and fired in air at the predetermined temperature and time shown in Table 4 to form a resist underlayer film with a thickness of approximately 50 nm. Hardness measurements were performed on the formed resist underlayer films. Film hardness was evaluated using a Bruker AXS TI-980 triboidentor. The measurement was performed on a wafer with a thickness of 55 nm using a Berkovich indenter (triangular pyramid), and the hardness was evaluated up to an indentation depth of 45 nm. The results are summarized in Table 4.

[0190]

[0191] [Optical Constants of the Resist Underlayer Film] The resist underlayer film formation compositions of Examples 1 to 7 or Comparative Examples 1 to 5 were each coated onto a silicon wafer using a spin coater. A resist underlayer film (thickness 50 nm) was formed by firing on a hot plate at the predetermined temperature and time shown in Table 5. The refractive index (n value) and optical absorption coefficient (k value, also called the attenuation coefficient) of these resist underlayer films at a wavelength of 193 nm were measured using a spectroscopic ellipsometer. The results are shown in Table 5.

[0192]

[0193] Based on these results, applying a resin consisting of a phenol derivative having two or more hydroxyl groups and a methylol compound to the resist underlayer film resulted in increased hardness of the underlayer film. Furthermore, by changing the type of compound reacted, the optical constants of the resist underlayer film can be freely controlled.

Claims

1. A composition for forming a resist underlayer film, comprising a resin (G) having a composite unit structure and a solvent, wherein the resin (G) is represented by the following formula (AB), and the composite unit structure comprises a unit structure (A) having an aromatic ring and a unit structure (B) having a methoxymethyl group, and the unit structure (A) has at least two hydroxyl groups bonded to the aromatic ring. (In equation (AB), A represents unit structure (A), and B represents unit structure (B).) 2. The resist underlayer film forming composition according to claim 1, wherein the unit structure (B) is derived from a compound represented by the following formula (1). (In formula (1), each R independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a methoxyisopropyl group, and at least one of the four Rs is a methyl group.) 3. The unit structure (A) has an aromatic ring skeleton having two or more hydroxy groups bonded to an aromatic ring, and the aromatic ring skeleton is represented by the following formula (A-4-1), the following formula (A-4-2), the following formula (A-4-3), the following formula (A-4-4), the following formula (A-4-5), the following formula (A-4-6), the following formula (A-4-7), the following formula (A-4-8), the following formula (A-4-9), the following formula (A-5a), the following formula (A-5b), the following formula (A-5c), the following formula (A-5d), and the following formula (A-6a). The composition for forming a resist underlayer film according to claim 1, comprising at least any one of the skeletons. (In the formula, n1, n2, n4, n5, n6, and n9 each independently represent an integer of 2 to 4. n3a, n3b, n7a, n7b, n8a, and n8b each independently represent an integer of 0 to 4. Provided that the sum of n3a and n3b is 2 or more, the sum of n7a and n7b is 2 or more, and the sum of n8a and n8b is 2 or more.) (In the formula, Ar ４１ each independently represent a residue of an aromatic ring. k1 and k2 each independently represent an integer of 1 or 2. X １ represents -O-, -CO-, -S-, -SO ２ -, or an alkylene group optionally substituted with a halogen atom. When k1 is 1, X ２１ represents a single bond, -O-, -CO-, -S-, -SO ２ -, or an alkylene group optionally substituted with a halogen atom. When k2 is 1, X ２２ represents a single bond, -O-, -CO-, -S-, -SO ２ -, or an alkylene group optionally substituted with a halogen atom. When k1 is 2, X ２１ represents a trivalent saturated hydrocarbon group optionally substituted with a halogen atom. When k2 is 2, X ２２ represents a trivalent saturated hydrocarbon group optionally substituted with a halogen atom. Y １ represents a trivalent saturated hydrocarbon group. Y ２ represents a tetravalent saturated hydrocarbon group. m1 and m2 each independently represent integers from 0 to 3, provided that the sum of m1 and m2 is 2 or greater. m3 to m5 each independently represent integers from 0 to 3, provided that the sum of m3 to m5 is 2 or greater. m6 to m8 each independently represent integers from 0 to 3, provided that the sum of m6 to m8 is 2 or greater. m9 to m12 each independently represent integers from 0 to 3, provided that the sum of m9 to m12 is 2 or greater. (In the formula, Ar ５１ Each of these independently represents a residue in an aromatic ring. n11 each independently represents an integer from 1 to 4.

4. The resist underlayer film forming composition according to claim 1, wherein the resin (G) is a resin synthesized by polymerizing a compound having an aromatic ring skeleton having two or more hydroxyl groups bonded to an aromatic ring and a compound having a methoxymethyl group in the presence of an acid catalyst.

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

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

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

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

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

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

12. A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film forming composition 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 the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film forming composition 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 the semiconductor substrate through the patterned resist underlayer film.

14. A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using a resist underlayer film forming composition 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 the 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 a resist underlayer film forming composition 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 removal of 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 the 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 nanoimprint or self-assembled film.

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

Images