Composition for forming resist underlayer film

Abstract

The purpose of the present invention is to provide 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, which have further improved properties such as curability, etching resistance, planarization, embeddability, and the like of the resist underlayer film. [Solution] A composition for forming a resist underlayer film, which contains a solvent and a polymer that contains at least one type of structural unit represented by formula (1). In formula (1), A is a divalent aryl group having any one of the structures I, II, and III, or a divalent aryl group having any combination of the structures I, II, and III, B is a divalent group represented by formula (2), and * represents a bond. I. Heterocyclic structure in which at least one aromatic ring and at least one heterocyclic ring containing nitrogen atom are fused, II. Aromatic ring structure in which only at least two benzene rings are fused, and III. Aromatic ring structure # imgabs0 in which at least one aromatic ring and at least one aliphatic ring are fused

Description

Technical Field

[0001] The present invention relates to a resist underlayer film-forming composition suitable for photolithography in semiconductor substrate processing, a resist underlayer film obtained from the resist underlayer film-forming composition, a method for forming a resist pattern using the resist underlayer film-forming composition, and a method for manufacturing a semiconductor device using the composition. Background Art

[0002] In recent years, the progress of semiconductor manufacturing processes has been rapidly advancing, and along with this, there has been a strong demand for higher quality and improved properties of resist underlayer films.

[0003] For example, Patent Document 1 reports that polymers containing a divalent group of a specific heteroaromatic ring containing an indole skeleton as a part of the structure and an aryl-substituted divalent group such as an aryl-substituted methylene group as structural units can be used as materials that achieve both film density and etching resistance. However, while planarization properties are mentioned, no evidence is provided.

[0004] Patent Document 2 reports that a novolac resin formed between a compound having an indolecarbazole structure and specific aromatic aldehyde compounds is obtained, which does not mix with the resist layer, has high dry etching resistance and high heat resistance, and has a low amount of sublimates.

[0005] Patent Document 3 also describes a method for producing a film structure comprising a polymer obtained by reacting a compound having a benzene ring or an aromatic heterocyclic structure with a compound having a large number of aromatic ring structures. It is reported that this method enables the production of a film structure having excellent planarization properties.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-151024

[0009] Patent Document 2: International Publication No. WO2017-094780

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2017-92457 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, with the rapid advancement of semiconductor manufacturing processes, there is a strong demand for higher quality and improved properties of resist underlayer films. Properties such as curability, etching resistance, planarization, and embedding properties are required, but these properties still have room for improvement.

[0013] Means for solving problems

[0014] The present invention solves the above-mentioned problems. Specifically, the present invention includes the following solutions.

[0015] A first aspect of the present invention relates to a resist underlayer film-forming composition comprising a polymer and a solvent, wherein the polymer comprises at least one structural unit represented by the following formula (1).

[0016]

[0017] (In formula (1), A is a divalent aromatic group having any one of the following structures I, II, and III, or a divalent aromatic group having any combination of the following structures I, II, and III, B is a divalent group represented by the following formula (2), and * represents a bonding bond.

[0018] I. Heterocyclic structure in which at least one aromatic ring is fused with at least one heterocyclic ring containing a nitrogen atom

[0019] II. Aromatic ring structure consisting only of at least two fused benzene rings

[0020] III. Aromatic ring structure in which at least one aromatic ring is fused with at least one aliphatic ring

[0021] In formula (2), B1 is a divalent group containing a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a benzo[9,10]phenanthrene ring, or a fluoranthene ring, and R is a halogen atom, or R is one or more groups selected from a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms, which may have a substituent. Examples of substituents include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxycarbonyl group having 1 to 6 carbon atoms. R may be the same or different. ** represents a bond.

[0022] A second aspect of the present invention relates to the resist underlayer film-forming composition according to the first aspect, wherein the structure of I is a structure represented by the following formula (4): The structure of II above is a pyrene derivative which may have a substituent. The structure of III above is a fluorene derivative which may have a substituent. The substituents include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an indolyl group, a 2-phenylindolyl group, a phenol group, a naphthol group, a hydroxypyrenyl group, an aryl group having 6 to 20 carbon atoms, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms.

[0023]

[0024] (In formula (4), Ar1 represents a benzene ring or a naphthalene ring, Ar2 represents a monocyclic or condensed ring having 4 to 30 carbon atoms and optionally containing heteroatoms, n represents the presence or absence of the structure of Ar2, n is 0 or 1, X is a substituent of Ar2, which may be the same or different, and represents a monovalent group having a monocyclic or condensed ring having 6 to 20 carbon atoms and optionally containing heteroatoms, m represents the number of X substituents, m = 0 to 3, and when m is 2 or 3, the X substituents may be directly fused to each other or bonded together via a single bond. A new ring is formed, L is a substituent of the pyrrole ring, representing a monovalent group containing 6 to 20 carbon atoms, which may contain heteroatoms, and a monocyclic or condensed ring. q represents the presence or absence of the L substituent and is 0 or 2. When n=1, q=0, and the L substituent is absent. When n=0, q is 0 to 2. Y represents a hydrogen atom or a linear, branched, or cyclic alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an alkenyl group containing 2 to 20 carbon atoms, or an alkynyl group containing 2 to 10 carbon atoms. ).

[0025] The third aspect of the present invention relates to the resist underlayer film-forming composition according to the second aspect, wherein the above formula (4) is an indolocarbazole derivative optionally having an X substituent.

[0026] A fourth aspect of the present invention relates to the resist underlayer film-forming composition according to the third aspect, wherein the indolocarbazole derivative is a divalent group derived from a compound represented by the following formula (A-1) to formula (A-3).

[0027]

[0028] A fifth aspect of the present invention relates to the resist underlayer film-forming composition according to the second aspect, wherein the fluorene derivative is a divalent group derived from a compound represented by the following formula (A-4) or (A-5).

[0029]

[0030] A sixth aspect of the present invention relates to the resist underlayer film-forming composition according to the first aspect, wherein the solvent has a boiling point of 160° C. or higher.

[0031] A seventh aspect of the present invention relates to the resist underlayer film-forming composition according to the first aspect, further comprising a cross-linking agent.

[0032] An eighth aspect of the present invention relates to the resist underlayer film-forming composition according to the seventh aspect, wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent.

[0033] A ninth aspect of the present invention relates to the resist underlayer film-forming composition according to the first aspect, further comprising a surfactant.

[0034] A tenth aspect of the present invention relates to the resist underlayer film-forming composition according to the first aspect, further comprising an acid and / or a salt thereof and / or an acid generator.

[0035] An eleventh aspect of the present invention relates to a resist underlayer film which is a fired product of a coating film formed from the composition according to any one of the first to tenth aspects.

[0036] The twelfth embodiment of the present invention relates to a method for forming a resist pattern for manufacturing a semiconductor, which comprises the following steps: a step of applying the resist underlayer film forming composition described in any one of the first to tenth embodiments onto a semiconductor substrate and firing the composition to form a resist underlayer film; a step of forming a resist film on the resist underlayer film; and a step of forming a resist pattern on the resist film by irradiating it with light or an electron beam and developing it.

[0037] The 13th embodiment of the present invention relates to a method for manufacturing a semiconductor device, which includes the following steps: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in any one of the 1st to 10th embodiments; a step of forming a resist film on the resist underlayer film; a step of forming a resist pattern on the resist film; a step of etching the resist underlayer film using the resist pattern; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[0038] A fourteenth aspect of the present invention relates to the method for manufacturing a semiconductor device according to the thirteenth aspect, wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development.

[0039] A fifteenth aspect of the present invention relates to the method for manufacturing a semiconductor device according to the thirteenth aspect, wherein the resist film is patterned by nanoimprinting or self-assembled film formation.

[0040] The 16th embodiment of the present invention relates to a method for manufacturing a semiconductor device, which includes the following steps: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in any one of the 1st to 10th embodiments; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; and a step of processing the semiconductor substrate using the patterned resist underlayer film.

[0041] A seventeenth aspect of the present invention relates to the method for manufacturing a semiconductor device according to the sixteenth aspect, wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor depositing a composition containing an inorganic substance.

[0042] An eighteenth aspect of the present invention relates to the method for manufacturing a semiconductor device according to the sixteenth aspect, wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development.

[0043] A nineteenth aspect of the present invention relates to the method for manufacturing a semiconductor device according to the sixteenth aspect, wherein the patterning of the resist film is performed by nanoimprinting or self-assembled film formation.

[0044] The 20th embodiment of the present invention relates to a method for manufacturing a semiconductor device, which includes the following steps: a step of forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition described in any one of the first to tenth embodiments; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; a step of removing the hard mask; and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[0045] A 21st aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 20th aspect, wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor deposition of a composition containing an inorganic substance.

[0046] A 22nd aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 20th aspect, wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development.

[0047] A 23rd aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 20th aspect, wherein the patterning of the resist film is performed by nanoimprinting or self-assembly.

[0048] A 24th aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 20th aspect, wherein the hard mask is removed by either etching or an alkaline chemical solution.

[0049] The 25th embodiment of the present invention relates to a method for manufacturing a semiconductor device, which includes the following steps: a step of forming a resist underlayer film on a semiconductor substrate using a resist underlayer film-forming composition described in any one of the first to tenth embodiments; a step of forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; a step of forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; a step of removing the hard mask; a step of forming a vapor-deposited film (spacer) on the resist underlayer film after the hard mask is removed; a step of processing the vapor-deposited film (spacer) by etching; a step of removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and a step of processing the semiconductor substrate using the patterned vapor-deposited film (spacer).

[0050] A 26th aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 25th aspect, wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor deposition of a composition containing an inorganic substance.

[0051] A 27th aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 25th aspect, wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development.

[0052] A 28th aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 25th aspect, wherein the patterning of the resist film is performed by nanoimprinting or self-assembly.

[0053] A 29th aspect of the present invention relates to the method for manufacturing a semiconductor device according to the 25th aspect, wherein the hard mask is removed by either etching or an alkaline chemical solution.

[0054] Effects of the Invention

[0055] The resist underlayer film-forming composition of the present invention exhibits excellent etching resistance, resulting in excellent coating properties on substrates with various height differences, resulting in excellent planarization and embedding properties. Furthermore, even without a crosslinking agent or acid catalyst, the composition exhibits sufficient solvent resistance under atmospheric conditions, resulting in sufficient curability. Therefore, it can be widely used in a variety of semiconductor manufacturing processes. DETAILED DESCRIPTION

[0056] The resist underlayer film-forming composition of the present invention is a resist underlayer film-forming composition comprising a polymer and a solvent, wherein the polymer comprises at least one structural unit represented by the following formula (1) and may optionally contain a crosslinking agent, an acid generator, or a surfactant.

[0057] Hereinafter, the details of each component will be described.

[0058]

[0059] * indicates a bonding bond.

[0060]

[0061] A is a divalent aryl group having any one of the following structures I, II, and III, or a divalent aryl group having any combination of the following structures I, II, and III.

[0062] I. Heterocyclic structure in which at least one aromatic ring is fused with at least one heterocyclic ring containing a nitrogen atom

[0063] II. Aromatic ring structure consisting only of at least two fused benzene rings

[0064] III. Aromatic ring structure in which at least one aromatic ring is fused with at least one aliphatic ring

[0065] Structure of I

[0066] The structure of I is represented by the following formula (4).

[0067]

[0068] (In formula (4), Ar1 represents a benzene ring or a naphthalene ring, Ar2 represents a monocyclic or condensed ring having 4 to 30 carbon atoms and optionally containing heteroatoms, n represents the presence or absence of the structure of Ar2, n is 0 or 1, X is a substituent of Ar2, which may be the same or different, and represents a monovalent group having a monocyclic or condensed ring having 6 to 20 carbon atoms and optionally containing heteroatoms, m represents the number of X substituents, m = 0 to 3, and when m is 2 or 3, the X substituents may be directly fused to each other or connected by a single bond. To form a new ring, L is a substituent of the pyrrole ring, representing a monovalent group containing 6 to 20 carbon atoms, which may contain heteroatoms, or a condensed ring. q represents the presence or absence of the L substituent and is 0 to 2. When n = 1, q = 0, indicating the absence of the L substituent. When n = 0, q is 0 to 2. Y represents a hydrogen atom or a linear, branched, or cyclic alkyl group containing 1 to 10 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an alkenyl group containing 2 to 20 carbon atoms, or an alkynyl group containing 2 to 10 carbon atoms.

[0069] Specific examples of the monocyclic or condensed ring having 4 to 30 carbon atoms which may contain a heteroatom include a benzene ring, a naphthalene ring, a pentalene ring, an indene ring, an azulene ring, a heptatrienol ring, an indacenyl ring, a perylene ring, a pentacene ring, a dihydroacenaphthene ring, a phenanthrene ring, an anthracene ring, a tetracene ring, Ring, benzo[9,10]phenanthrene ring, fluorene ring, pyridine ring, quinoline ring, isoquinoline ring, imidazole ring, benzimidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, triazole ring, benzotriazole ring, Azole ring, benzo azole ring, imidazoline ring, pyrazine ring, quinoxaline ring, pyrimidine ring, quinazoline ring, pyridazine ring, triazine ring, pyrrole ring, indole ring, isoindole ring, carbazole ring and condensed rings containing these rings. Among them, the carbazole ring is preferred.

[0070] The substituent X of Ar2 and the substituent L of the pyrrole ring represent a monovalent group containing a monocyclic or condensed ring having 6 to 20 carbon atoms which may contain a heteroatom. Examples of the monocyclic or condensed ring having 6 to 20 carbon atoms which may contain a heteroatom include the examples of the monocyclic or condensed ring having 4 to 30 carbon atoms which may contain a heteroatom described in the above paragraph, wherein the number of carbon atoms is within 6 to 20.

[0071] Specific examples of the linear, branched or cyclic alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl ...butyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1 Methyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclopropyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclo Butyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1 -cycloalkyl groups such as n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropyl, 2-isopropyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl and 2-ethyl-3-methyl-cyclopropyl; cross-linked cycloalkyl groups such as dicyclobutyl, dicyclopentyl, dicyclohexyl, dicycloheptyl, dicyclooctyl, dicyclononyl and dicyclodecyl;

[0072] Specific examples of the aryl group having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, 1-naphthyl, 2-naphthyl, 5-naphthyl, 2- 1-Pyrenyl, 2-Pyrenyl, Pentaphenyl, Benzopyrenyl, Benzo[9,10]phenanthrenyl; Biphenyl-2-yl (o-biphenyl), Biphenyl-3-yl (m-biphenyl), Biphenyl-4-yl (p-biphenyl), p-terphenyl-4-yl, m-terphenyl-4-yl, o-terphenyl-4-yl, 1,1'-binaphthyl-2-yl, 2,2'-binaphthyl-1-yl, etc., but are not limited to these.

[0073] Specific examples of the alkenyl group having 2 to 20 carbon atoms include ethenyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, and n-1-eicosenyl.

[0074] Specific examples of the alkynyl group having 2 to 10 carbon atoms include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n-1-hexynyl, and n-1-decynyl.

[0075] Examples of the structure of I include divalent groups derived from compounds represented by the following formulae, but are not limited to the following examples.

[0076]

[0077] Among them, the structure of I is preferably a structure having an indolocarbazole skeleton in which Ar1 is a benzene ring and Ar2 is carbazole. For example, it is a divalent group derived from a compound represented by the following formula.

[0078]

[0079] The structure of I is more preferably a divalent group derived from a compound represented by the following formula (A-1) to formula (A-3).

[0080]

[0081] Structure of II

[0082] The structure of II is an aromatic ring structure composed of at least two benzene rings fused together. Examples thereof include naphthalene, anthracene, phenanthrene, tetracene, pentacene, benzopyrene, The derivatives include derivatives of benzo[9,10]phenanthrene, pyrene, benzo[9,10]phenanthrene, coronene, and ovalene. The number of fused aromatic rings is preferably 6 or less, and examples include derivatives of naphthalene, anthracene, phenanthrene, and pyrene.

[0083] In addition, the condensed aromatic ring in the structure II may have a substituent. Examples of the substituent include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an indolyl group, a 2-phenylindolyl group, a phenol group, a naphthol group, a hydroxypyrenyl group, an aryl group having 6 to 20 carbon atoms, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxycarbonyl group having 1 to 6 carbon atoms.

[0084] Specific examples of the acyl group having 2 to 6 carbon atoms include acetyl, propionyl, butyryl, isobutyryl, valeryl, 2-methylbutyryl, 3-methylbutyryl, pivaloyl, n-hexanoyl, 4-methylvaleryl, 3,3-dimethylbutyryl, heptanoyl, and cyclohexanecarbonyl.

[0085] Specific examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group.

[0086] Specific examples of the alkoxycarbonyl group having 1 to 6 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, and an isopropoxycarbonyl group.

[0087] Examples of the structure of II include divalent groups derived from compounds represented by the following formulae, but are not limited to the following examples.

[0088]

[0089] Structure of III

[0090] The structure of III is an aromatic ring structure in which at least one aromatic ring is fused with at least one aliphatic ring. Examples thereof include derivatives of indane, fluorene, 1,2-benzofluorene, 2,3-benzofluorene, fluoranthene, benzo[b]fluoranthene, and acenaphthene. Preferred are indane derivatives and fluorene derivatives. More preferred are fluorene derivatives.

[0091] Furthermore, in the structure of III, the fused aromatic ring structure may have a substituent. Examples of the substituent include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an indolyl group, a 2-phenylindolyl group, a phenol group, a naphthol group, a hydroxypyrenyl group, an aryl group having 6 to 20 carbon atoms, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxycarbonyl group having 1 to 6 carbon atoms.

[0092] Furthermore, examples of the structure of III include divalent groups derived from compounds represented by the following formulae, but are not limited to the following examples.

[0093]

[0094] Among them, the structure of III is preferably a divalent group derived from a compound represented by the following formula (A-4) or formula (A-5).

[0095]

[0096]

[0097] B is a divalent group represented by the following formula (2).

[0098]

[0099] In formula (2), B1 is a divalent group containing a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a benzo[9,10]phenanthrene ring, or a fluoranthene ring, and R is a halogen atom, or R is one or more groups selected from a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms, which may have a substituent. Examples of such substituents include a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxycarbonyl group having 1 to 6 carbon atoms. R may be the same or different. ** represents a bond.

[0100] <Production of a polymer containing a structural unit represented by formula (1)>

[0101] The polymer containing the composite unit structure AB represented by the above formula (1) can be prepared by a known method. For example, it can be prepared by fusing the ring-containing compound A with the ring-containing compound B. Here, in the formula, A and B have the same meanings as above.

[0102] The ring-containing compound A and the ring-containing compound B may be used alone or in combination of two or more. In the condensation reaction, the ring-containing compound B may be used in a ratio of 0.1 to 10 mol, preferably 0.1 to 2 mol, per 1 mol of the ring-containing compound A.

[0103] The above condensation reaction can be carried out without a solvent, but is usually carried out using a solvent. As the solvent, there is no particular limitation as long as it can dissolve the reaction substrate and does not hinder the reaction. For example, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, tetrahydrofuran, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate ... In addition, if the catalyst used is a liquid substance such as formic acid, it can also serve as a solvent.

[0104] The condensation reaction temperature is usually 40° C. to 200° C., preferably 80° 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.

[0105] The weight average molecular weight of the polymer comprising the composite unit structure AB represented by formula (1) according to one embodiment of the present invention is usually 500 to 100,000, preferably 600 to 50,000, 700 to 10,000, or 800 to 8,000.

[0106] Solvents

[0107] The resist underlayer film-forming composition according to one embodiment of the present invention contains a solvent.

[0108] The solvent is not particularly limited as long as it can dissolve the polymer containing the structural unit represented by formula (1) and other optional components added as needed.

[0109] Examples of the solvent include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, Ethyl ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, lactic acid Butyl Lactate, Isobutyl Lactate, Methyl Formate, Ethyl Formate, Propyl Formate, Isopropyl Formate, Butyl Formate, Isobutyl Formate, Amyl Formate, Isoamyl Formate, Methyl Acetate, Ethyl Acetate, Amyl Acetate, Isoamyl Acetate, Hexyl Acetate, Methyl Propionate, Ethyl Propionate, Propyl Propionate, Isopropyl Propionate, Butyl Propionate, Isobutyl Propionate, Methyl Butyrate, Ethyl Butyrate, Propyl Butyrate, Isopropyl Butyrate, Butyl Butyrate, Isobutyl Butyrate, Ethyl Hydroxyacetate, Methyl 2-Hydroxy-2-Methylpropionate, Ethyl 2-Hydroxy-2-Methylpropionate, Methyl 3-Methoxy-2-Methylpropionate, Methyl 2-Hydroxy-3-Methylbutyrate, Ethyl Methoxyacetate Ester, ethyl ethoxylate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

[0110] Furthermore, a solvent having a boiling point of 160°C or higher and a solvent having a boiling point of less than 160°C may be contained in combination.

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

[0112]

[0113] [R in formula (i) 1 、R 2 and R 3 Each represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be interrupted by an oxygen atom, a sulfur atom or an amide bond, and may be the same or different, or may be bonded to form a ring structure.]

[0114] Alternatively, 1,6-diacetoxyhexane (boiling point 260° C.) and tripropylene glycol monomethyl ether (boiling point 242° C.) described in JP-A-2021-84974, and various high-boiling-point solvents described in paragraph 0082 of the publication can be preferably used.

[0115] Alternatively, dipropylene glycol monomethyl ether acetate (boiling point 213°C), diethylene glycol monoethyl ether acetate (boiling point 217°C), diethylene glycol monobutyl ether acetate (boiling point 247°C), dipropylene glycol dimethyl ether (boiling point 171°C), dipropylene glycol monomethyl ether (boiling point 187°C), dipropylene glycol monobutyl ether (boiling point 231°C), tripropylene glycol monomethyl ether (boiling point 231°C), and dipropylene glycol monomethyl ether (boiling point 231°C) described in Japanese Patent Application Laid-Open No. 2019-20701 can be preferably used. The present invention also includes various high-boiling-point solvents as described in paragraphs 0023 to 0031 of the publication, such as 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-butanediol diacetate (boiling point 232°C), and the various high-boiling-point solvents as described in paragraphs 0023 to 0031 of the publication.

[0116] <Acid and / or its salt and / or acid generator>

[0117] The resist underlayer film-forming composition as one embodiment of the present invention may contain an acid and / or a salt thereof and / or an acid generator.

[0118] Examples of the acid include p-toluenesulfonic acid, trifluoromethanesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthoic acid.

[0119] As the salt, salts of the above-mentioned acids can also be used. The salt is not limited, and ammonia derivative salts such as trimethylamine salt and triethylamine salt, pyridine derivative salt, morpholine derivative salt, etc. can be preferably used.

[0120] The acid and / or its salt may be used alone or in combination of two or more. The amount thereof blended 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 solid content.

[0121] Examples of the acid generator include thermal acid generators and photoacid generators.

[0122] Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienonone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE [registered trademark] CXC-1612, K-PURE CXC-1614, K-PURETAG-2172, K-PURETAG-2179, K-PURETAG-2678, K-PURETAG 2689, and K-PURETAG 2700 (manufactured by King Industries), SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), and organic sulfonic acid alkyl esters.

[0123] Photoacid generators generate acid when the resist is exposed. This allows the acidity of the underlying film to be adjusted. This is one method for aligning the acidity of the underlying film with that of the overlying resist. Furthermore, by adjusting the acidity of the underlying film, the pattern shape of the resist formed overlying the resist can be adjusted.

[0124] Examples of the photoacid generator contained in the resist underlayer film-forming composition of the present invention include Salt compounds, sulfonimide compounds and disulfonyldiazomethane compounds, etc.

[0125] As Salt compounds, such as diphenyl iodide Hexafluorophosphate, diphenyl iodide Trifluoromethanesulfonate, diphenyl iodide Nonafluorobutanesulfonate, diphenyl iodide Perfluorooctane sulfonate, diphenyl iodide Camphorsulfonate, bis(4-tert-butylphenyl)iodide Camphorsulfonate and bis(4-tert-butylphenyl)iodide trifluoromethanesulfonate and other iodine Sulfonium salt compounds, and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0126] Examples of the sulfonyl imide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoro-n-butanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0127] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0128] The acid generator may be used alone or in combination of two or more.

[0129] When an acid generator is used, the ratio thereof is 0.01 to 10 parts by mass, 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass relative to 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0130] <Other optional ingredients>

[0131] The resist underlayer film-forming composition as one embodiment of the present invention may contain, in addition to the above-mentioned components, a crosslinking agent, a surfactant, a light absorber, a rheology modifier, an adhesion promoter, a curing catalyst, and the like as needed.

[0132] Cross-linking agent

[0133] Representative crosslinking agents include aminoplast crosslinking agents and phenoplast crosslinking agents.

[0134] As the crosslinking agent, a highly heat-resistant crosslinking agent can be used. As the highly heat-resistant crosslinking agent, a compound containing a crosslinking-forming substituent having an aromatic ring (eg, a benzene ring or a naphthalene ring) in the molecule can be preferably used.

[0135] Examples of aminoplast crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated melamine, benzoguanamine, glycoluril, urea, and polymers thereof. Preferred crosslinking agents include those having at least two crosslinking substituents, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or butoxymethylated thiourea. Condensates of these compounds may also be used.

[0136] It is preferably at least one selected from tetramethoxymethyl glycoluril and hexamethoxymethylmelamine.

[0137] Some specific examples are as follows.

[0138]

[0139] Examples of phenolic plastic crosslinking agents include highly alkylated, alkoxylated, or alkoxyalkylated aromatic compounds, and polymers thereof. Preferred crosslinking agents have at least two crosslinking substituents per molecule, such as 2,6-dihydroxymethyl-4-methylphenol, 2,4-dihydroxymethyl-6-methylphenol, bis(2-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, bis(4-hydroxy-3-hydroxymethyl-5-methylphenyl)methane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, bis(3-formyl-4-hydroxyphenyl)methane, bis(4-hydroxy-2,5-dimethylphenyl)formylmethane, and α,α-bis(4-hydroxy-2,5-dimethylphenyl)-4-formyltoluene. Condensates of these compounds may also be used.

[0140] Examples of such compounds include, in addition to the above, compounds having a partial structure of the following formula (11) and polymers or oligomers having a repeating unit of the following formula (12).

[0141]

[0142] The above R 11 、R 12 、R 13 and R 14 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the alkyl groups exemplified above can be used. n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) represents an integer of 2 to 5. n3 is an integer of 1 to 4, n4 is 0 to (4-n3), and (n3+n4) represents an integer of 1 to 4. Oligomers and polymers can be used with a repeating unit structure ranging from 2 to 100 or 2 to 50.

[0143] Some specific examples are as follows.

[0144]

[0145] R: -H or -CH(CH3)CH2OCH3

[0146] Crosslinking agents such as aminoplast crosslinking agents and phenoplast crosslinking agents may be used alone or in combination of two or more. Aminoplast crosslinking agents can be produced by a known method or a method based thereon, or commercially available products may be used.

[0147] The amount of crosslinking agents such as aminoplast crosslinking agents and phenolic plastic crosslinking agents used varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 mass % or more, 0.01 mass % or more, 0.05 mass % or more, 0.5 mass % or more, or 1.0 mass % or more, and 80 mass % or less, 50 mass % or less, 40 mass % or less, 20 mass % or less, or 10 mass % or less relative to the total solid content of the resist underlayer film-forming composition according to the present invention.

[0148] Surfactants

[0149] The resist underlayer film-forming composition according to the present invention may contain a surfactant in order to prevent the occurrence of pinholes, streaks, and the like and to further improve the coating properties on uneven surfaces.

[0150] Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene / polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. EF301, EF303, EF352 (manufactured by ケトムプロダクツ Co., Ltd., trade name), EF303, EF352 171. F173, R-30, R-40 (trade name manufactured by Dainippon Technology Co., Ltd.), Fururo FC430, FC43 1 (trade name manufactured by Sumitomo Solar Co., Ltd.), ASUNALA AG710, SANE S-382, SC101, S Fluorine-based surfactants such as C102, SC103, SC104, SC105, SC106 (trade name manufactured by Asahi Glass Co., Ltd.), Organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc.

[0151] The amount of these surfactants added is usually 2.0% by mass or less, preferably 1.0% by mass or less, based on the total solid content of the resist underlayer film-forming composition according to the present invention. These surfactants may be added alone or in combination of two or more.

[0152] <Other additives>

[0153] As the light absorber, commercially available light absorbers described in, for example, "Technology and Market of Industrial Pigments" (published by CMC) and "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry) can be suitably used, for example, CI Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; CI Disperse Orange 1, 5, 13, CI Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; CI Disperse Violet 43; CI Disperse Blue 96; CI Fluorescent Brighteners 112, 135, and 163; CI Solvent Orange 2 and 45; CI Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; CI Pigment Green 10; CI Pigment Brown 2, etc. The light absorber is usually blended in a ratio of 10% by mass or less, preferably 5% by mass or less, based on the total solids content of the resist underlayer film-forming composition of the present invention.

[0154] The rheology modifier is added primarily to improve the fluidity of the resist underlayer film-forming composition, particularly to improve the thickness uniformity of the resist underlayer film during the baking step and to improve the filling properties of the resist underlayer film-forming composition into the pores. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butylisodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di(n-butyl) maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology control agents are usually blended in a ratio of less than 30% by mass based on the total solid content of the resist underlayer film-forming composition according to the present invention.

[0155] The adhesion aid is mainly added to improve the adhesion between the substrate or the resist and the resist underlayer film-forming composition, and in particular, 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; silanes such as vinyltrichlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, and 2-mercaptobenzothiazole. Heterocyclic compounds such as azole, ureaazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine, and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters are usually blended in a ratio of less than 5% by mass, preferably less than 2% by mass, based on the total solid content of the resist underlayer film-forming composition according to the present invention.

[0156] A curing catalyst is effective for curing the film. Specific examples include, but are not limited to, sulfonium salt compounds such as triphenylsulfonium nitrate, triphenylsulfonium maleate, triphenylsulfonium trifluoroacetate, triphenylsulfonium hydrochloride, and triphenylsulfonium acetate.

[0157] The resist underlayer film-forming composition of the present invention has a solid content of 0.1 to 70% by mass or 0.1 to 60% by mass. The solid content refers to the content of all components in the resist underlayer film-forming composition after removing the solvent. A crosslinkable resin may be included in the solid content at a ratio of 1 to 99.9% by mass, 50 to 99.9% by mass, 50 to 95% by mass, or 50 to 90% by mass.

[0158] <Resist underlayer film>

[0159] The resist underlayer film can be formed using the resist underlayer film-forming composition according to the present invention, for example, as follows.

[0160] On a substrate used in the manufacture of a semiconductor device (for example, a silicon wafer substrate, a silicon dioxide-coated substrate (SiO2 substrate), a silicon nitride substrate (SiN substrate), a silicon oxide nitride substrate (SiON substrate), a titanium nitride substrate (TiN substrate), a tungsten substrate (W substrate), a glass substrate, an ITO substrate, a polyimide substrate, and a low dielectric constant material (low-k material) coated substrate, etc.), a resist underlayer film-forming composition as one embodiment of the present invention is applied by an appropriate coating method such as a spin coater or a coater, and then fired using a heating means such as a hot plate to form a resist underlayer film. As conditions for firing, a firing temperature of 80°C to 800°C and a firing time of 0.3 to 60 minutes are appropriately selected. Preferably, the firing temperature is 150°C to 400°C and the firing time is 0.5 to 2 minutes. As the atmospheric gas during firing, air can be used, or an inert gas such as nitrogen or argon can be used. In one embodiment, it is particularly preferred that the oxygen concentration is 1% or less. Here, the thickness of the formed underlayer film is, for example, 10 to 1000 nm, 20 to 500 nm, 30 to 400 nm, or 50 to 300 nm. In addition, if a quartz substrate is used as the substrate, a replica of the quartz imprint mold (mold replica) can be produced.

[0161] In addition, a bonding layer and / or a silicon-containing layer comprising less than 99% by mass or less than 50% by mass of Si can also be formed on the resist underlayer film as one embodiment of the present invention by coating or vapor deposition. For example, in addition to the method of forming the bonding layer described in Japanese Unexamined Patent Publication No. 2013-202982, Japanese Patent No. 5827180, or the resist underlayer film (inorganic resist underlayer film) containing silicon described in International Publication No. 2009 / 104552 (A1) by spin coating, a Si-based inorganic material film can also be formed by CVD method etc.

[0162] In addition, by coating the composition for forming an anti-etching agent underlayer film as one embodiment of the present invention on a semiconductor substrate having a portion with a height difference and a portion without a height difference (a so-called height difference substrate) and firing it, the height difference between the portion with a height difference and the portion without a height difference can be reduced.

[0163] <Method for Forming a Resist Pattern>

[0164] A method for forming a resist pattern used in the manufacture of semiconductors includes the following steps: a step of applying the resist underlayer film-forming composition of the present invention onto a substrate used in the manufacture of the above-mentioned semiconductor device and firing the composition to form a resist underlayer film; a step of forming a resist film on the resist underlayer film; and a step of forming a resist pattern on the resist film by irradiating it with light or an electron beam and developing it.

[0165] <Method for manufacturing a semiconductor device>

[0166] (i)

[0167] A method for manufacturing a semiconductor device according to one embodiment of the present invention includes the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition as one embodiment of the present invention; forming a resist film on the resist underlayer film; A process of forming a resist pattern on a resist film by irradiating it with light or an electron beam and developing it; a step of etching the resist underlayer film using the resist pattern to perform patterning; and A step of processing a semiconductor substrate using the patterned resist underlayer film.

[0168] (ii)

[0169] Furthermore, a method for manufacturing a semiconductor device as one embodiment of the present invention includes the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition as one embodiment of the present invention; forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; A process of forming a resist pattern on a resist film by irradiating it with light or electron beams and developing it. A process of etching the hard mask using the resist pattern to perform patterning; a step of etching the resist underlayer film using the patterned hard mask to perform patterning; and A step of processing a semiconductor substrate using the patterned resist underlayer film.

[0170] (iii)

[0171] Furthermore, a method for manufacturing a semiconductor device as one embodiment of the present invention includes the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition as one embodiment of the present invention; forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; A process of forming a resist pattern on a resist film by irradiating it with light or an electron beam and developing it; A process of etching the hard mask using the resist pattern to perform patterning; A step of etching the resist underlayer film using the patterned hard mask to perform patterning; A process of removing the hard mask; and A step of processing a semiconductor substrate using the patterned resist underlayer film.

[0172] (iv)

[0173] Furthermore, a method for manufacturing a semiconductor device as one embodiment of the present invention includes the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition as one embodiment of the present invention; forming a hard mask on the resist underlayer film; a step of further forming a resist film on the hard mask; A process of forming a resist pattern on a resist film by irradiating it with light or an electron beam and developing it; A process of etching the hard mask using the resist pattern to perform patterning; a step of etching the resist underlayer film using the etched hard mask to perform patterning; A step of removing the hard mask; a step of forming a vapor-deposited film (spacer) on the resist underlayer film after the hard mask is removed; a step of processing the vapor-deposited film (spacer) by etching; a step of removing the patterned resist underlayer film to leave the patterned vapor-deposited film (spacer); and A step of processing a semiconductor substrate using the patterned vapor-deposited film (spacer).

[0174] The semiconductor substrate can be processed using the manufacturing methods (i) to (iv) above.

[0175] The step of forming a resist underlayer film using the resist underlayer film-forming composition as one embodiment of the present invention is as described in the above section <Resist underlayer film>.

[0176] A hard mask such as a film containing silicon may be formed as a second resist underlayer film on the resist underlayer film formed in the above steps, and a resist pattern may be formed thereon [the above (ii) to (iv)].

[0177] The hard mask may be a coating film of a composition containing an inorganic substance, or a vapor-deposited film of an inorganic substance formed by a vapor deposition method such as CVD or PVD, and examples thereof include a SiON film, a SiN film, or a SiO 2 film.

[0178] An anti-reflection film (BARC) may be further formed on the hard mask, or a resist shape correction film having no anti-reflection capability may be formed.

[0179] In the process of the above-mentioned formation resist pattern, exposure is carried out by being used to form the mask (photomask) of prescribed pattern or by directly describing.The exposure source can use such as g-ray, i-ray, KrF excimer laser, ArF excimer laser, EUV, electron beam.After exposure, carry out post-exposure heating (PostExposureBake) as required.Then, develop by developer (such as 2.38 quality % tetramethylammonium hydroxide aqueous solution), further rinse with rinse solution or pure water, the developer used is removed.Then, carry out post-bake for the drying of resist pattern and improving the adhesion with substrate.

[0180] The etching step performed after the resist pattern is formed is performed by dry etching.

[0181] The resist film may be patterned by a nanoimprint method or a self-assembled film method.

[0182] In the nanoimprint method, a resist composition is formed using a mold (mold) that is transparent to the irradiated light and has been patterned. In addition, in the self-assembled film method, a self-assembled film that naturally forms a nanoscale regular structure using a diblock polymer (polystyrene-polymethyl methacrylate, etc.) is used to perform patterning.

[0183] In the nanoimprint method, before applying the curable composition that becomes the resist film, a layer containing silicon (hard mask layer) can be arbitrarily formed on the resist underlayer film by coating or vapor deposition, and further a bonding layer can be formed on the resist underlayer film or on the layer containing silicon (hard mask layer) by coating or vapor deposition, and the curable composition that becomes the resist film is applied on the bonding layer.

[0184] It should be noted that the following gases can be used in the processing of the hard mask (silicon-containing layer) / resist underlayer film / substrate: CF4, CHF3, CH2F2, CH3F, C4F6, C4F8, O2, N2O, NO2, He, and H2. These gases can be used alone or as a mixture of two or more. Furthermore, these gases can be mixed with argon, nitrogen, carbon dioxide, carbonyl sulfide, sulfur dioxide, neon, or nitrogen trifluoride.

[0185] It should be noted that wet etching is sometimes performed to simplify the process and reduce damage to the processed substrate. This suppresses variations in processing dimensions and reduces pattern roughness, allowing substrate processing with a high yield. Therefore, in the above (iii) to (iv), the hard mask can also be removed by etching or using an alkaline solution. In particular, when using an alkaline solution, there is no limitation on the composition, but the following components are preferably included as the alkaline component.

[0186] Examples of the alkaline component include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide, methyltributylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldiethylammonium hydroxide, benzyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, (2-hydroxyethyl)trimethylammonium hydroxide, monoethanolamine, diethanolamine, triethanolamine, 2-(2-aminoethoxy)ethanol, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N- Examples include 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-piperidinol, cyclohexylamine, and 1,5-diazabicyclo[4,3,0]-5-nonene. Tetramethylammonium hydroxide and tetraethylammonium hydroxide are particularly preferred from a handling perspective. An inorganic base and a quaternary ammonium hydroxide may also be used in combination. Preferred inorganic bases include alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and rubidium hydroxide, with potassium hydroxide being more preferred.

[0187] Example

[0188] Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples, and comparative examples. However, the present invention is not limited to the following examples.

[0189] [Synthesis of polymers]

[0190] The synthesis of the structural formulas (S'1) and (S'2) of the comparative example polymers used as the resist underlayer film and the synthesis of the structural formulas (S1) to (S9) of the example polymers used the following compound group A, compound group B, compound group C, catalyst group D, solvent group E, and reprecipitation solvent group F.

[0191] (Compound Groups A to C)

[0192] (Catalyst Group D)

[0193] Methanesulfonic acid: D1

[0194] 3-Mercaptopropionic acid: D2

[0195] Tetrabutylammonium iodide: D3

[0196] (Solvent Group E)

[0197] Propylene glycol monomethyl ether acetate (=PGMEA): E1

[0198] Tetrahydrofuran: E2

[0199] Sodium hydroxide aqueous solution: E3

[0200] (Reprecipitation Solvent Group F)

[0201] Methanol: F1

[0202] (Separation solvent group G)

[0203] Butyl acetate / water: G1

[0204] Synthesis example 1

[0205] 12.7 g of (A1), 7.3 g of (B6), 0.9 g of (D1) and 48.8 g of (E1) were added to a flask. Then, the mixture was heated at 100° C. under nitrogen and reacted for about 3 hours. After the reaction was stopped, it was reprecipitated with (F1) and dried to obtain a resin (S'1). The weight average molecular weight Mw measured by GPC in terms of polystyrene was about 2,500. The obtained resin was dissolved in PGMEA, and ion exchange was performed for 4 hours using a cation exchange resin and an anion exchange resin to obtain a target compound solution.

[0206]

[0207] The weight average molecular weight of the polymer is a result of measurement by gel permeation chromatography (hereinafter referred to as GPC). A GPC apparatus manufactured by Tosoh Corporation was used for the measurement, and the measurement conditions and the like are as follows.

[0208] Device: HLC-8320GPC manufactured by Higashikata Co., Ltd.

[0209] GPC column: TSKgelSuper-MultiporeHZ-N (2 columns)

[0210] Column temperature: 40°C

[0211] Flow rate: 0.35mL / min

[0212] Eluent: THF

[0213] Standard sample: polystyrene

[0214] Synthesis Examples 2 to 11

[0215] By changing Compound Group A, Compound Group B, Compound Group C, Catalyst Group D, Solvent Group E, and Reprecipitation Solvent Group F, polymers for use in resist underlayer films were synthesized. The experimental procedures were the same as those in Synthesis Example 1. Comparative Example polymers (S'1) and (S'2), Example polymers (S1) to (S9), and their solutions were synthesized under the following conditions.

[0216] [Table 1]

[0217] Synthesis example 12

[0218] The flask was charged with 10.0 g of the resin (S9), 10.5 g of (C1), 0.5 g of (D2), 24.5 g of (E2), and 18.2 g of (E3) obtained after the reprecipitation treatment in Synthesis Example 5. Then, the mixture was heated to 55°C under nitrogen and reacted for about 24 hours. After the reaction stopped, the liquid separation operation was repeated with (G1), the organic layer was concentrated, redissolved in PGMEA, reprecipitated using (F1), and dried to obtain resin (S10). The weight average molecular weight Mw measured by GPC in terms of polystyrene was about 3,900. The obtained resin was dissolved in PGMEA, and ion exchange was performed for 4 hours using a cation exchange resin and an anion exchange resin to obtain the target compound solution.

[0219]

[0220] [Preparation of Resist Underlayer Film]

[0221] Polymers (S1) to (S8), (S10), (S'1), (S'2), a crosslinking agent (CR1), an acid generator (Ad1), a solvent (propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and a surfactant, Megaffac R-40 (manufactured by DIC Corporation, R-40), were mixed in the proportions shown in the table below and filtered using a 0.1 μm polytetrafluoroethylene microfilter to prepare resist underlayer film materials (Examples M1 to M9, Comparative Examples M1 to M3).

[0222]

[0223] [Table 2]

[0224] [Dissolution test of resist solvent]

[0225] The resist lower layer film materials of Examples M1-M9 and Comparative Examples M1-M3 were fired at 400°C for 60 seconds to adjust the concentration to about 100 nm. For the film, ACT-8 manufactured by Tokyo Elektronik Co., Ltd. was used to coat the resist lower layer film material on a silicon wafer, and the film was fired at the specified temperature / specified time described in the table under the atmosphere to form a 100 nm resist lower layer film. The formed resist lower layer film was immersed in PGME / PGMEA=7 / 3 as a general diluent for 60 seconds to confirm its resistance to solvents. The case where the reduction rate of the film thickness before and after diluent immersion is less than 1% is judged as ○ (Table 3). It should be noted that the samples that do not show solvent resistance under the firing conditions in the atmosphere are difficult to evaluate as resist lower layers, so they are not evaluated in subsequent tests.

[0226] [Measurement of etching rate]

[0227] The etcher and etching gas used in the etching measurement are as follows.

[0228] CF4 gas: RIE-200NL (Samco): CF450sccm

[0229] N2 / O2 gas: RIE-200NL (Samco): N2200sccm, O210sccm

[0230] The resist underlayer film materials of Examples M1-M9 and Comparative Examples M2 and M3 were fired at 400°C for 60 seconds to adjust the concentration to approximately 100 nm. The materials were then coated and fired on silicon wafers using a spin coater. The dry etching rates were measured using CF4 and O2 / N2 gases as etching gases. The dry etching rate ratio was defined as (resist underlayer film) / (KrF resist), and compositions with a rate ratio of less than 0.85 were rated as ○ (Table 3).

[0231] [Test of embedding properties into uneven substrates]

[0232] As a coating test on a high-contrast substrate, the unpatterned open areas (OPEN) and 50nm-wide grooves on a 100nm-thick SiO2 substrate were confirmed to be filled with a resist underlayer film. The resist underlayer film-forming compositions of Examples M1-M9 and Comparative Examples M2 and M3 were applied to the above-mentioned substrates and then fired at 400°C for 60 seconds to form a resist underlayer film of approximately 100nm. The flattening properties of the substrates were observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Tech Norodom Devices Co., Ltd.; filling without voids was considered good and the embedding properties were judged as 0 (Table 3).

[0233] [Table 3]

[0234] As described above, the use of the polymer obtained in the present invention allows the polymer alone to exhibit sufficient solvent resistance not only in atmospheric air but also to exhibit sufficient etching resistance against common etching gases such as F- and O-based gases. Furthermore, the polymer exhibits excellent embedding properties into patterned substrates. From these perspectives, it is expected to be applicable to a wide range of semiconductor devices.

[0235] Industrial availability

[0236] The resist underlayer film material used in the photolithography process using a multilayer film of the present invention shows excellent etching resistance, has good flattening and embedding properties in a micro-processed substrate, can obtain an excellent resist pattern, and can provide a resist underlayer film with sufficient curing properties even if it is a polymer alone.

Claims

1. A resist underlayer film-forming composition comprising a polymer and a solvent, wherein the polymer comprises at least one structural unit represented by the following formula (1): In formula (1), A is a divalent aromatic group having any one of the following structures I, II, and III, or a divalent aromatic group having any combination of the following structures I, II, and III, B is a divalent group represented by the following formula (2), * represents a bonding bond; I. a heterocyclic structure in which at least one aromatic ring is fused with at least one heterocyclic ring containing a nitrogen atom, II. an aromatic ring structure consisting solely of at least two fused benzene rings, III. an aromatic ring structure in which at least one aromatic ring is fused with at least one aliphatic ring, In formula (2), B1 is a divalent group containing a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a benzo[9,10]phenanthrene ring or a fluoranthene ring; R is a halogen atom, or R is one or more groups selected from a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms and an alkynyl group having 2 to 10 carbon atoms, which may have a substituent; as a substituent, it is a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms; R may be the same or different; ** represents a bond.

2. The resist underlayer film-forming composition according to claim 1, wherein the structure of I is represented by the following formula (4): The structure of II is a pyrene derivative which may have a substituent. The structure of III is a fluorene derivative which may have a substituent. The substituent is a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a trifluoromethyl group, a halogen atom, an indolyl group, a 2-phenylindolyl group, a phenol group, a naphthol group, a hydroxypyrenyl group, an aryl group having 6 to 20 carbon atoms, an acyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxycarbonyl group having 1 to 6 carbon atoms; In formula (4), Ar1 represents a benzene ring or a naphthalene ring, Ar2 represents a monocyclic or condensed ring having 4 to 30 carbon atoms and optionally containing heteroatoms, n represents the presence or absence of the structure of Ar2, n is 0 or 1, X is a substituent of Ar2, which may be the same or different, and represents a monovalent group having a monocyclic or condensed ring having 6 to 20 carbon atoms and optionally containing heteroatoms, m represents the number of X substituents, m = 0 to 3, and when m is 2 or 3, the X substituents may be directly fused to each other or connected by a single bond. To form a new ring, L is a substituent of the pyrrole ring, which represents a monovalent group having 6 to 20 carbon atoms and which may contain heteroatoms, a monocyclic or condensed ring, q represents the presence or absence of the L substituent, and is 0 to 2. When n = 1, q = 0, and the L substituent does not exist. When n = 0, q is 0 to 2. Y represents a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. 3 . The resist underlayer film-forming composition according to claim 2 , wherein the formula (4) is an indolocarbazole derivative which may have a substituent group X.

4. The resist underlayer film-forming composition according to claim 3, wherein the indolocarbazole derivative is a divalent group derived from a compound represented by the following formula (A-1) to formula (A-3): 。 5. The resist underlayer film-forming composition according to claim 2, wherein the fluorene derivative is a divalent group derived from a compound represented by the following formula (A-4) or formula (A-5); 。 6 . The resist underlayer film-forming composition according to claim 1 , wherein the solvent has a boiling point of 160° C. or higher. 7 . The resist underlayer film-forming composition according to claim 1 , further comprising a cross-linking agent. 8 . The resist underlayer film-forming composition according to claim 7 , wherein the crosslinking agent is an aminoplast crosslinking agent or a phenoplast crosslinking agent. 9 . The resist underlayer film-forming composition according to claim 1 , further comprising a surfactant. 10 . The resist underlayer film-forming composition according to claim 1 , further comprising an acid and / or a salt thereof and / or an acid generator. 11 . A resist underlayer film which is a fired product of a coating film formed from the composition according to claim 1 .

12. A method for forming a resist pattern for manufacturing a semiconductor, comprising the following steps: a step of applying the resist underlayer film-forming composition according to any one of claims 1 to 10 onto a semiconductor substrate and firing the composition to form a resist underlayer film; a step of forming a resist film on the resist underlayer film; and a step of forming a resist pattern on the resist film by irradiating the resist film with light or an electron beam and developing the resist film.

13. A method for manufacturing a semiconductor device, comprising the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 10; forming a resist film on the resist underlayer film; forming a resist pattern on the resist film; a step of etching the resist underlayer film using the resist pattern; and A step of processing a semiconductor substrate using the patterned resist underlayer film. 14 . The method for manufacturing a semiconductor device according to claim 13 , wherein a resist pattern is formed on the resist film by irradiation with light or electron beams and development. 15 . The method for manufacturing a semiconductor device according to claim 13 , wherein the patterning of the resist film is performed by nanoimprinting or self-assembled film formation.

16. A method for manufacturing a semiconductor device, comprising the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 10; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; and A step of processing a semiconductor substrate using the patterned resist underlayer film. 17 . The method for manufacturing a semiconductor device according to claim 16 , wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor depositing a composition containing an inorganic substance. 18 . The method for manufacturing a semiconductor device according to claim 16 , wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development. 19 . The method for manufacturing a semiconductor device according to claim 16 , wherein the patterning of the resist film is performed by nanoimprinting or self-assembled film.

20. A method for manufacturing a semiconductor device, comprising the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 10; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; removing the hard mask; and A step of processing a semiconductor substrate using the patterned resist underlayer film. 21 . The method for manufacturing a semiconductor device according to claim 20 , wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor depositing a composition containing an inorganic substance. 22 . The method for manufacturing a semiconductor device according to claim 20 , wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development. 23 . The method for manufacturing a semiconductor device according to claim 20 , wherein the patterning of the resist film is performed by nanoimprinting or self-assembled film. 24 . The method for manufacturing a semiconductor device according to claim 20 , wherein the hard mask is removed by either etching or an alkaline chemical solution.

25. A method for manufacturing a semiconductor device, comprising the following steps: A step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of claims 1 to 10; forming a hard mask on the resist underlayer film; further forming a resist film on the hard mask; forming a resist pattern on the resist film; a step of etching the hard mask using the resist pattern; a step of etching the resist underlayer film using the patterned hard mask; A step of removing the hard mask; A step of forming a vapor-deposited film, i.e., a spacer, on the resist underlayer film after the hard mask is removed; a step of processing the vapor-deposited film, i.e., the spacer, by etching; a step of removing the patterned resist underlayer film to leave the patterned vapor-deposited film, i.e., the spacer; and A step of processing a semiconductor substrate using the patterned vapor-deposited film, ie, spacers. 26 . The method for manufacturing a semiconductor device according to claim 25 , wherein the hard mask is formed by coating a composition containing an inorganic substance or vapor depositing a composition containing an inorganic substance. 27 . The method for manufacturing a semiconductor device according to claim 25 , wherein a resist pattern is formed on the resist film by irradiation with light or an electron beam and development. 28 . The method for manufacturing a semiconductor device according to claim 25 , wherein the patterning of the resist film is performed by nanoimprint lithography or self-assembled film formation.

29. The method for manufacturing a semiconductor device according to claim 25, wherein the hard mask is removed by either etching or an alkaline chemical solution.

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