Resist underlayer film forming composition using diarylmethane derivative

Abstract

The present invention provides a resist underlayer film forming composition which is capable of forming a flat film that exhibits high etching resistance, a good dry etching rate ratio and a good optical constant, while having good coverage even with respect to a so-called multileveled substrate and having a small difference in the film thickness after embedding. The present invention also provides: a method for producing a polymer that is suitable for this resist underlayer film forming composition; a resist underlayer film which uses this resist underlayer film forming composition; and a method for producing a semiconductor device. This resist underlayer film forming composition contains: a reaction product of an aromatic compound (A) that has from 6 to 120 carbon atoms, and a compound that is represented by formula (1); and a solvent. (In formula (1), Z represents –(C=O)- or -C(-OH)-; each of Ar1 and Ar2 independently represents an optionally substituted phenyl, naphthyl, anthracenyl or pyrenyl group; and ring Y represents an optionally substituted cyclic aliphatic ring, an optionally substituted aromatic ring, or a fused ring of optionally substituted cyclic aliphatic ring and aromatic ring.)

Description

[Technical Field]

[0001] The present invention relates to a resist underlayer film-forming composition that exhibits high etching resistance and favorable optical constants, has good coverage even on so-called uneven substrates, and is capable of forming a film with high embedding properties for fine patterns; a method for producing a polymer suitable for the resist underlayer film-forming composition; a resist underlayer film using the resist underlayer film-forming composition; and a method for producing a semiconductor device. [Background technology]

[0002] In recent years, resist underlayer film materials for multilayer resist processes have been required to function as anti-reflective coatings, particularly for short-wavelength exposure, have appropriate optical constants, and also have etching resistance during substrate processing. For this reason, the use of polymers having repeating units containing benzene rings has been proposed (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-354554 Summary of the Invention [Problem to be solved by the invention]

[0004] To achieve thinner resist layers as resist patterns become finer, a lithography process is known in which at least two resist underlayer films are formed and used as a mask. This involves providing at least one organic film (underlayer organic film) and at least one inorganic underlayer film on a semiconductor substrate, patterning the inorganic underlayer film using a resist pattern formed on an upper resist film as a mask, and then patterning the lower organic film using the pattern as a mask. This method is said to be capable of forming patterns with high aspect ratios. Examples of materials for forming the at least two layers include combinations of organic resins (e.g., acrylic resins, novolac resins) and inorganic materials (e.g., silicon resins (e.g., organopolysiloxanes), inorganic silicon compounds (e.g., SiON, SiO2), etc.). Furthermore, in recent years, double patterning technology, which involves two lithography processes and two etching processes to obtain a single pattern, has been widely applied, with the above-mentioned multilayer process being used in each step. In this case, the organic film formed after the initial pattern is required to have the ability to fill in fine patterns in addition to the ability to flatten steps.

[0005] However, there is also a problem that the composition for forming a resist underlayer film has low coverage for so-called uneven substrates, where the resist pattern formed on the substrate to be processed has differences in height or density, and it is difficult to form a film with high embedding properties for fine patterns.

[0006] The present invention has been made based on the solution to these problems, and an object of the present invention is to provide a resist underlayer film-forming composition that exhibits high etching resistance, a good dry etching rate ratio and optical constants, has good coverage even for so-called uneven substrates, and is capable of forming a film with high embedding ability for fine patterns. Another object of the present invention is to provide a resist underlayer film and a method for producing a semiconductor device using the resist underlayer film-forming composition. [Means for solving the problem]

[0007] The present invention encompasses the following. [1] A resist underlayer film-forming composition comprising a reaction product of an aromatic compound (A) having 6 to 120 carbon atoms and a compound represented by the following formula (1), and a solvent: [ka] [In formula (1), Z represents -(C=O)- or -C(-OH)-; Ar1 ​​and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group; and ring Y represents an optionally substituted cyclic aliphatic group, an optionally substituted aromatic group, or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.] [2] The resist underlayer film-forming composition according to [1], wherein the reaction product is such that one carbon atom in ring Y is bonded to one of the aromatic compounds (A), and one carbon atom in Ar1 or Ar2 is bonded to another of the aromatic compounds (A). [3] The resist underlayer film forming composition according to [1] or [2], wherein the compound represented by formula (1) is represented by the following formula (1a): [ka] [In formula (1a), Z represents -(C=O)-, Ar1 and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic group or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.] [4] The resist underlayer film-forming composition according to [1], wherein the reaction product has one carbon atom in the ring Y linked to two of the aromatic compounds (A). [5] The resist underlayer film forming composition according to [4], wherein the ring Y in the formula (1a) is a fused ring structure containing a cyclohexene ring. [6] The resist underlayer film-forming composition according to [5], wherein in the formula (1a), ring Y represents a condensed ring of a cyclic aliphatic and an aromatic group. [7] The resist underlayer film forming composition according to any one of [1] to [3], wherein the compound represented by formula (1) is represented by the following formula (1b): [ka] [In formula (1b), Z represents —C(—OH)—, Ar1 and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic, an optionally substituted aromatic, or a fused ring of an optionally substituted cyclic aliphatic and an aromatic.] [8] The resist underlayer film forming composition according to [7], wherein the formula (1b) is an aromatic compound. [9] The resist underlayer film forming composition according to [8], wherein in the formula (1b), Y contains a naphthalene ring.

[10] The resist underlayer film-forming composition according to any one of [1] to [9], wherein in the formula (1), Ar1 and Ar2 each independently represent a phenyl group or a naphthyl group optionally substituted with a hydroxy group.

[11] The resist underlayer film-forming composition according to any one of [1] to

[10] , wherein the aromatic compound (A) contains one or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or combinations thereof.

[12] The resist underlayer film-forming composition according to any one of [1] to

[10] , wherein the aromatic compound (A) contains two or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or a combination thereof.

[13] The resist underlayer film forming composition according to any one of [1] to

[12] , further comprising a crosslinking agent.

[14] The resist underlayer film forming composition according to any one of [1] to

[13] , further comprising an acid and / or an acid generator.

[15] The resist underlayer film forming composition according to any one of [1] to

[14] , wherein the boiling point of the solvent is 160°C or higher.

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

[15] .

[17] A method for manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to

[15] ; forming a resist film thereon; forming a resist pattern by irradiating with light or an electron beam and developing; etching the underlayer film using the resist pattern; and processing a semiconductor substrate using the patterned underlayer film.

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

[17] , wherein the step of forming the resist underlayer film is carried out by a nanoimprint method. [Effects of the Invention]

[0008] The resist underlayer film-forming composition of the present invention not only has high etching resistance and good optical constants, but also the resist underlayer film obtained has good coverage even on so-called uneven substrates and forms a film with high embedding properties for fine patterns, thereby achieving finer substrate processing. In particular, the resist underlayer film forming composition of the present invention is effective in a lithography process in which at least two resist underlayer films are formed to reduce the resist film thickness, and the resist underlayer film is used as an etching mask. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Resist underlayer film-forming composition] The resist underlayer film forming composition according to the present invention contains a reaction product of an aromatic compound (A) having 6 to 120 carbon atoms and a compound represented by the following formula (1), and a solvent. [ka] [In formula (1), Z represents -(C=O)- or -C(-OH)-; Ar1 ​​and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group; and ring Y represents an optionally substituted cyclic aliphatic group, an optionally substituted aromatic group, or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.] The following explains each step in turn.

[0010] [Aromatic compounds (A) having 6 to 120 carbon atoms] The aromatic compound (A) having 6 to 120 carbon atoms is (a) may be a monocyclic compound such as benzene, phenol, or phloroglucinol; (b) may be a fused ring compound such as naphthalene, dihydroxynaphthalene, naphthol, 9,10-anthraquinone, or indenofluorenedione; (c) may be a heterocyclic compound such as furan, thiophene, pyridine, carbazole, phenothiazine, phenoxazine, or indolocarbazole; (d) A compound in which the aromatic rings of (a) to (c) are bonded together by a single bond, such as biphenyl, phenylindole, 9,9-bis(4-hydroxyphenyl)fluorene, α,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene, or 9,9-fluorenylidene-bisnaphthol, (e) -(CH2), such as phenylnaphthylamine n The aromatic rings (a) to (d) may be compounds in which the aromatic rings are linked with a spacer exemplified by -(n=1 to 20), -CH=CH-, -C≡C-, -N=N-, -NH-, -NR-, -NHCO-, -NRCO-, -S-, -COO-, -OCO-, -O-, -CO- and -CH=N-.

[0011] Examples of aromatic compounds include benzene, thiophene, furan, pyridine, pyrimidine, pyrazine, pyrrole, oxazole, thiazole, imidazole, naphthalene, anthracene, quinoline, carbazole, fluorene, quinazoline, purine, indolizine, benzothiophene, benzofuran, indole, phenylindole, and acridine.

[0012] The aromatic compound (A) may be an aromatic compound containing an amino group, a hydroxyl group, or both, or an arylamine compound, a phenol compound, or both. Aromatic amines or phenolic hydroxy group-containing compounds are preferred. Examples of aromatic amines include aniline, diphenylamine, phenylnaphthylamine, hydroxydiphenylamine, phenylnaphthylamine, N,N'-diphenylethylenediamine, and N,N'-diphenyl-1,4-phenylenediamine. Examples of the phenolic hydroxy group-containing compound include phenol, dihydroxybenzene, trihydroxybenzene, hydroxynaphthalene, dihydroxynaphthalene, trihydroxynaphthalene, tris(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)ethane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, and polynuclear phenols.

[0013] Examples of the polynuclear phenol include dihydroxybenzene, trihydroxybenzene, hydroxynaphthalene, dihydroxynaphthalene, trihydroxynaphthalene, tris(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)ethane, 2,2'-biphenol, and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane.

[0014] The hydrogen atoms of the aromatic compound (A) having 6 to 120 carbon atoms may be substituted with an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a fused ring group, a heterocyclic group, a hydroxy group, a formyl group, an amino group, a nitro group, an ether group, an alkoxy group, a cyano group, or a carboxyl group.

[0015] Examples of the alkyl group having 1 to 20 carbon atoms include linear or branched alkyl groups that may or may not have a substituent, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, cyclohexyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, p-tert-butylcyclohexyl group, n-decyl group, n-dodecylnonyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group. Preferably, it is an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms. Examples of the alkenyl group having 2 to 10 carbon atoms and the alkynyl group having 2 to 10 carbon atoms include linear or branched alkenyl groups and alkynyl groups that may or may not have a substituent, such as a vinyl group, an ethynyl group, a 2-propenyl group, a 2-propynyl group, a 2-butenyl group, a 2-butynyl group, a 3-butenyl group, and a 3-butynyl group.

[0016] Examples of alkyl groups having 1 to 20 carbon atoms interrupted by an oxygen atom, a sulfur atom, or an amide bond include those containing the structural unit -CH2-O-, -CH2-S-, -CH2-NHCO-, or -CH2-CONH-. The -O-, -S-, -NHCO-, or -CONH- may be present in one unit or in two or more units in the alkyl group. Specific examples of alkyl groups having 1 to 20 carbon atoms interrupted by -O-, -S-, -NHCO-, or -CONH- units include methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, propylcarbonylamino, butylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, propylaminocarbonyl, butyl ... and the like, and further, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, or octadecyl groups, each of which is substituted with a methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, or the like. Preferred are methoxy, ethoxy, methylthio, and ethylthio groups, and more preferred are methoxy and ethoxy groups. Examples of the alkenyl group having 2 to 10 carbon atoms and the alkynyl group having 2 to 10 carbon atoms which may be interrupted by an oxygen atom include a 2-propenyloxy group, a 2-propynyloxy group, a 3-butenyloxy group, a 3-butynyloxy group, and a 2-(ethynyloxy)ethoxy group.

[0017] The fused ring group is a substituent derived from a fused ring compound, and specific examples thereof include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a naphthacenyl group, a triphenylenyl group, a pyrenyl group, and a chrysenyl group. Of these, a phenyl group, a naphthyl group, an anthracenyl group, and a pyrenyl group are preferred.

[0018] The heterocyclic group is a substituent derived from a heterocyclic compound, and specific examples thereof include a thiophene group, a furan group, a pyridine group, a pyrimidine group, a pyrazine group, a pyrrole group, an oxazole group, a thiazole group, an imidazole group, a quinoline group, a carbazole group, a quinazoline group, a purine group, an indolizine group, a benzothiophene group, a benzofuran group, an indole group, an acridine group, an isoindole group, a benzimidazole group, an isoquinoline group, a quinoxaline group, a cinnoline group, a pteridine group, a chromene group (benzopyran group), an isochromene group (benzopyran group), a xanthene group, Examples of such groups include a thiazole group, a pyrazole group, an imidazoline group, and an azine group. Among these, a thiophene group, a furan group, a pyridine group, a pyrimidine group, a pyrazine group, a pyrrole group, an oxazole group, a thiazole group, an imidazole group, a quinoline group, a carbazole group, a quinazoline group, a purine group, an indolizine group, a benzothiophene group, a benzofuran group, an indole group, and an acridine group are preferred, and a thiophene group, a furan group, a pyridine group, a pyrimidine group, a pyrrole group, an oxazole group, a thiazole group, an imidazole group, and a carbazole group are most preferred. The nitrogen atom on these heterocycles may be substituted with an alkenyl group having 2 to 10 carbon atoms or an alkynyl group having 2 to 10 carbon atoms.

[0019] The above aromatic compounds may be linked together via a single bond or a spacer. An example of a spacer is -(CH2) n Examples thereof include one or a combination of two or more of -(n=1 to 20), -CH=CH-, -C≡C-, -N=N-, -NH-, -NR-, -NHCO-, -NRCO-, -S-, -COO-, -OCO-, -O-, -CO-, -Ph-, -Ph-Ph-, -Ph-O-Ph-(Ph=C6H4), and -CH=N-. Two or more of these spacers may be linked together. Examples of the substituent R on the nitrogen atom include the above-mentioned linear or branched alkyl groups having 1 to 20 carbon atoms, which may or may not have a substituent.

[0020] The aromatic compound (A) preferably contains one or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or a combination thereof, and more preferably contains two or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or a combination thereof. In addition, the aromatic compound (A) may be a condensed ring of two or more kinds of aromatic compounds (A) as long as the number of carbon atoms does not exceed 120.

[0021] Examples of the aromatic compound (A) include the compounds described below.

[0022] [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] Suitable examples of the aromatic compound (A) include, but are not limited to, 1-naphthaldehyde, 1-pyrenecarboxaldehyde, 9-fluorenone, carbazole, N-phenyl-1-naphthylamine, 2-phenylindole, 2,2'-biphenol, 1,5-dihydroxynaphthalene, and 9,9-bis(4-hydroxyphenyl)fluorene. The aromatic compound (A) may be one or two or more types, but is preferably one or two types.

[0028] [Compound represented by formula (1)] In the above formula (1), Ar1 and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group. Examples of the substituent include a hydroxy group, an alkyl group having 1 to 20 carbon atoms which may be substituted with a carbonyl group and which may be interrupted by an oxygen atom or a sulfur atom, a hydroxy group, an oxo group, a carboxy group, a cyano group, a nitro group, a sulfo group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, an amino group, a glycidyl group, an aryl group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, etc. These substituents may be bonded to Ar1 and / or Ar2 via an oxygen atom.

[0029] The alkyl group having 1 to 20 carbon atoms is as exemplified for the aromatic compound (A) having 6 to 120 carbon atoms. Examples of the acyl group having 1 to 6 carbon atoms include a formyl group and an acetyl group. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, etc. Examples of the alkoxycarbonyl group having 1 to 6 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, etc. Examples of aryl groups having 6 to 20 carbon atoms include phenyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, o-methoxyphenyl, p-methoxyphenyl, α-naphthyl, β-naphthyl, o-biphenylyl, m-biphenylyl, p-biphenylyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, and fluorene. Examples of alkenyl groups having 2 to 10 carbon atoms include vinyl and allyl. Examples of alkynyl groups having 2 to 10 carbon atoms include ethynyl. The heteroatoms, ring compounds, connecting rings, and fused rings are as described above.

[0030] Preferably, in the formula (1), Ar1 and Ar2 each independently represent a phenyl or naphthyl group optionally substituted with a hydroxy group.

[0031] In the above formula (1), ring Y represents an optionally substituted cyclic aliphatic group, an optionally substituted aromatic group, or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.

[0032] Examples of cyclic aliphatic groups include, but are not limited to, monocyclic groups such as cyclohexane and cyclohexene, polycyclic groups such as bicyclo[3.2.1]octane and bicyclo[2.2.1]hept-2-ene, and spirocyclic groups such as spirobicyclopentane.

[0033] Examples of aromatic groups include, but are not limited to, benzene, indene, naphthalene, azulene, anthracene, phenanthrene, naphthacene, triphenylene, pyrene, and chrysene.

[0034] Examples of fused cyclic aliphatic and aromatic rings include, but are not limited to, benzo[a]cyclohexene, benzo[b]cyclohexene, 1,2,3,4-tetrahydronaphthalene, and fluorene.

[0035] The substituents are as exemplified above for Ar1 and Ar2.

[0036] In the compound represented by formula (1), it is preferred that, upon reaction with the aromatic compound (A), one carbon atom in ring Y is linked to one of the aromatic compounds (A) and one carbon atom in Ar1 or Ar2 is linked to another of the aromatic compounds (A), or one carbon atom in ring Y is linked to two of the aromatic compounds (A).

[0037] Preferably, the compound represented by formula (1) is represented by the following formula (1a): [ka] [In formula (1a), Z represents -(C=O)-, Ar1 and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic group or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.]

[0038] Ar1, Ar2, Y and their substituents are as exemplified in relation to formula (1) above.

[0039] Preferably, ring Y in formula (1a) is a fused ring structure containing a cyclohexene ring. Preferably, ring Y in formula (1a) represents a fused ring of a cyclic aliphatic and an aromatic ring. More preferably, ring Y in formula (1a) represents a fused ring of a cyclohexene ring and an aromatic ring. Most preferably, ring Y in formula (1a) represents a fused ring of a cyclohexene ring and a benzene ring.

[0040] Preferably, the compound represented by formula (1) is represented by the following formula (1b): [ka] [In formula (1b), Z represents —C(—OH)—, Ar1 and Ar2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic, an optionally substituted aromatic, or a fused ring of an optionally substituted cyclic aliphatic and an aromatic.]

[0041] Ar1, Ar2, Y and their substituents are as exemplified in relation to formula (1) above.

[0042] Preferably, the formula (1b) is an aromatic compound. More preferably, in the formula (1b), Y contains a naphthalene ring. Most preferably, in the formula (1b), Y is a naphthalene ring.

[0043] Particularly preferred examples of the compound represented by the above formula (1) include p-naphtholbenzein and α-naphtholbenzein.

[0044] The compound represented by formula (1) may be one or more types, preferably one or two types. Also, for example, a combination of one or more types of compounds represented by formula (1a) and one or more types of compounds represented by formula (1b) may be used.

[0045] [Reaction products] By reacting the aromatic compound (A) with the carbonyl group or hydroxymethylene group of the compound represented by formula (1), a reaction product (polymer) can be obtained in which one carbon atom in ring Y of the compound represented by formula (1) is linked to one of the aromatic compounds (A) and one carbon atom in Ar1 or Ar2 is linked to another of the aromatic compounds (A), or a reaction product (polymer) in which one carbon atom in ring Y of the compound represented by formula (1) is linked to two of the aromatic compounds (A).

[0046] Examples of the acid catalyst used in the 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, and methanesulfonic acid; and carboxylic acids such as formic acid and oxalic acid. The amount of the acid catalyst used varies depending on the type of acid used. The amount is usually 0.001 to 10,000 parts by mass, preferably 0.01 to 1,000 parts by mass, and more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the aromatic compound (A).

[0047] The above condensation and addition reactions can be carried out without solvent, but are usually carried out using a solvent. Any solvent that does not inhibit the reaction can be used. Examples include ethers such as 1,2-dimethoxyethane, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, tetrahydrofuran, and dioxane, esters such as propylene glycol monomethyl ether acetate, and ketones such as N-methylopyrrolidone. The reaction temperature is usually the reflux temperature of the reaction mixture, preferably 40° C. to 200° C. The reaction time varies depending on the reaction temperature, but is usually about 30 minutes to 50 hours. The weight average molecular weight Mw of the polymer obtained as described above is usually 200 to 10,000, preferably 300 to 5,000, or 400 to 4,000.

[0048] The reaction products suitable for use in the present invention will be described in the examples.

[0049] [solvent]

[0033] The solvent for the resist underlayer film-forming composition of the present invention is not particularly limited, as long as it can dissolve the reaction product. In particular, since the resist underlayer film-forming composition of the present invention is used in the form of a homogeneous solution, it is recommended to use a solvent that is generally used in lithography processes in combination with the composition, taking into consideration its coating performance.

[0050] Examples of such solvents include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoether ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol 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 dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate,Butyl butyrate, isobutyl butyrate, ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl Examples of suitable solvents include 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

[0051] In addition, the following compounds described in WO2018 / 131562 A1 can also be used. [ka] (R in formula (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, and may be the same or different and may be bonded to each other to form a ring structure.

[0052] Examples of the alkyl group having 1 to 20 carbon atoms include linear or branched alkyl groups that may or may not have a substituent, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, cyclohexyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, p-tert-butylcyclohexyl group, n-decyl group, n-dodecylnonyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group. Preferably, it is an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms.

[0053] Examples of alkyl groups having 1 to 20 carbon atoms interrupted by an oxygen atom, a sulfur atom, or an amide bond include those containing the structural unit -CH2-O-, -CH2-S-, -CH2-NHCO-, or -CH2-CONH-. The -O-, -S-, -NHCO-, or -CONH- may be present in one unit or in two or more units in the alkyl group. Specific examples of alkyl groups having 1 to 20 carbon atoms interrupted by -O-, -S-, -NHCO-, or -CONH- units include methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, propylcarbonylamino, butylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, propylaminocarbonyl, butyl ... and the like, and further, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, or octadecyl groups, each of which is substituted with a methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, or the like. Preferred are methoxy, ethoxy, methylthio, and ethylthio groups, and more preferred are methoxy and ethoxy groups.

[0054] These solvents have a relatively high boiling point, and are therefore effective in imparting high embedding properties and high planarization properties to the resist underlayer film-forming composition.

[0055] Specific examples of preferred compounds represented by formula (i) are shown below. [ka]

[0056] Among the above, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, and The following formula: [ka] Compounds represented by the formula (i) are preferably 3-methoxy-N,N-dimethylpropionamide and N,N-dimethylisobutyramide.

[0057] These solvents can be used alone or in combination. Among these solvents, those with a boiling point of 160°C or higher are preferred, including propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, 2,5-dimethylhexane-1,6-diyl diacetate (DAH; cas. 89182-68-3), and 1,6-diacetoxyhexane (cas. 6222-17-9). Particularly preferred are propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and N,N-dimethylisobutyramide.

[0058] [Crosslinking agent component] The resist underlayer film-forming composition of the present invention may contain a crosslinker component. Examples of such crosslinkers include melamine-based crosslinkers, substituted urea-based crosslinkers, and polymers thereof. A crosslinker having at least two crosslink-forming substituents is preferred, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, or methoxymethylated thiourea. Condensates of these compounds may also be used.

[0059] In addition, a crosslinking agent having high heat resistance can be used as the crosslinking agent. As a crosslinking agent having high heat resistance, a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used.

[0060] This compound may be a compound having a partial structure of the following formula (4), or a polymer or oligomer having a repeating unit of the following formula (5). [ka] 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 mentioned above can be used. n1 is an integer of 1 to 4, n2 is an integer of 1 to (5-n1), and (n1+n2) is an integer of 2 to 5. n3 is an integer of 1 to 4, n4 is an integer of 0 to (4-n3), and (n3+n4) is an integer of 1 to 4. The number of repeating unit structures of the oligomers and polymers that can be used ranges from 2 to 100 or 2 to 50.

[0061] Examples of the compounds, polymers and oligomers of formula (4) and formula (5) are shown below. [ka] [ka]

[0062] The above compounds are available as products of Asahi Organic Chemicals Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above crosslinking agents, the compound of formula (4-24) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TM-BIP-A.

[0063] In addition to the above compounds, compounds having the following structures can also be used as crosslinking agents.

[0064] [ka]

[0065] The amount of crosslinking agent added varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 to 80 mass % of the total solids content, preferably 0.01 to 50 mass %, and more preferably 0.05 to 40 mass %. These crosslinking agents may undergo a crosslinking reaction by self-condensation, but when crosslinkable substituents are present in the above-mentioned reaction product of the present invention, they can undergo a crosslinking reaction with these crosslinkable substituents.

[0066] [Acid and / or its salt and / or acid generator] The resist underlayer film-forming composition of the present invention may contain an acid and / or a salt thereof and / or an acid generator. Examples of the acid include carboxylic acid compounds such as 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; and inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. etc. The salt may be a salt of the aforementioned acid, and although not limited thereto, preferred salts include ammonia derivative salts such as trimethylamine salts and triethylamine salts, pyridine derivative salts such as pyridinium p-toluenesulfonate, and morpholine derivative salts. The amount of the acid or salt thereof to be used is usually 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 5% by mass, based on the total solid content.

[0067] Examples of the acid generator include thermal acid generators and photoacid generators. Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG2689, and TAG2700 (manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (manufactured by Sanshin Chemical Industry Co., Ltd.), as well as quaternary ammonium salts of trifluoroacetic acid and other organic alkyl sulfonates.

[0068] Photoacid generators generate acid when the resist is exposed to light. This allows the acidity of the underlayer film to be adjusted. This is one way to match the acidity of the underlayer film to that of the upper layer resist. Adjusting the acidity of the underlayer film also allows for adjustment of the pattern shape of the upper layer resist. Examples of the photoacid generator contained in the resist underlayer film-forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0069] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0070] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0071] Examples of disulfonyldiazomethane compounds include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0072] The acid generators may be used singly or in combination of two or more. When an acid generator is used, the proportion thereof is 0.01 to 5 parts by mass, or 0.1 to 3 parts by mass, or 0.5 to 1 part by mass, relative to 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0073] [Other ingredients] The resist undercoat forming composition of the present invention can contain a surfactant to further improve coating properties against surface irregularities without generating pinholes, striations, etc. Examples of surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl 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; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monolaurate; polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monostearate; polyoxyethylene sorbitan monooleate; polyoxyethylene sorbitan trioleate; polyoxyethylene sorbitan monolaurate; polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monoole ... Examples of suitable surfactants include nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorine-containing surfactants such as F-TOP EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, R-40, R-40N, and R-40LM (trade names, manufactured by DIC Corporation), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). 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 material. These surfactants may be used alone or in combination of two or more. When a surfactant is used, the proportion thereof is 0.0001 to 5 parts by mass, or 0.001 to 1 part by mass, or 0.01 to 0.5 parts by mass, based on 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0074] The resist underlayer film-forming composition of the present invention may contain a light absorber, a rheology modifier, an adhesion promoter, etc. The rheology modifier is effective in improving the fluidity of the underlayer film-forming composition. The adhesion promoter is effective in improving the adhesion between the semiconductor substrate or resist and the underlayer film.

[0075] Examples of the light-absorbing agent include commercially available light-absorbing agents described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as CI Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; CI Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; CI Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; CI Disperse Violet 43; CI Disperse Blue 96; and CI Fluorescent Brightening Agent. Suitable examples of the light absorbent that can be used include CI Solvent Orange 2 and 45, CI Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49, CI Pigment Green 10, and CI Pigment Brown 2. The light absorbent is typically blended in an amount of 10% by mass or less, and preferably 5% by mass or less, based on the total solid content of the resist undercoat-forming composition.

[0076] Rheology modifiers are added primarily to improve the fluidity of the resist underlayer film-forming composition, particularly in the baking process, to improve the film thickness uniformity of the resist underlayer film and the ability of the resist underlayer film-forming composition to fill holes. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically added in an amount of less than 30% by mass based on the total solids content of the resist underlayer film-forming composition.

[0077] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the resist underlayer film-forming composition, and particularly to prevent the resist from peeling off during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylmethylolchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylmethylolethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; methyloltrimethylsilane; and methyloltrimethylsilane. Examples of suitable adhesion promoters include silanes such as chlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters are typically blended in an amount of less than 5% by mass, and preferably less than 2% by mass, based on the total solids content of the resist undercoat-forming composition.

[0078] The solids content of the resist underlayer film-forming composition according to the present invention is usually 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solids content is the content of all components of the resist underlayer film-forming composition excluding the solvent. The proportion of the reaction product in the solids content is preferably 1 to 100% by mass, 1 to 99.9% by mass, 50 to 99.9% by mass, 50 to 95% by mass, and 50 to 90% by mass, in that order.

[0079] One measure for evaluating whether a resist underlayer film-forming composition is in a uniform solution state is to observe its passability through a specific microfilter. The resist underlayer film-forming composition of the present invention passes through a microfilter with a pore size of 0.1 μm and exhibits a uniform solution state.

[0080] Examples of the microfilter material include fluorine-based resins such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PE (polyethylene), UPE (ultra-high molecular weight polyethylene), PP (polypropylene), PSF (polysulfone), PES (polyethersulfone), and nylon, with PTFE (polytetrafluoroethylene) being preferred.

[0081] [Method of manufacturing resist underlayer film and semiconductor device] Hereinafter, a method for producing a resist underlayer film and a semiconductor device using the resist underlayer film-forming composition according to the present invention will be described.

[0082] The resist underlayer film-forming composition of the present invention is applied to a substrate used in the manufacture of a semiconductor device (e.g., a silicon wafer substrate, a silicon dioxide substrate (SiO2 substrate), a silicon nitride substrate (SiN substrate), a silicon oxynitride substrate (SiON substrate), a titanium nitride substrate (TiN substrate), a tungsten substrate (W substrate), a glass substrate, an ITO substrate, a polyimide substrate, or a substrate coated with a low-dielectric-constant material (low-k material)) by a suitable application method such as a spinner or coater, followed by baking to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 80°C to 500°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 400°C and the baking time is 0.5 to 2 minutes. The thickness of the underlayer film formed here is, for example, 10 to 1000 nm, 20 to 500 nm, 30 to 300 nm, or 50 to 200 nm. The firing atmosphere can be either air or nitrogen.

[0083] Furthermore, an inorganic resist underlayer film (hard mask) can be formed on the organic resist underlayer film according to the present invention. For example, a silicon-containing resist underlayer film (inorganic resist underlayer film)-forming composition described in WO2009 / 104552A1 can be formed by spin coating, or a Si-based inorganic material film can be formed by a CVD method or the like.

[0084] Furthermore, by applying the resist underlayer film-forming composition according to the present invention to a semiconductor substrate having a portion with a step and a portion without a step (a so-called stepped substrate) and baking it, a resist underlayer film can be formed in which the step between the portion with a step and the portion without a step is in the range of 3 to 50 nm.

[0085] A resist film, such as a photoresist layer, is then formed on the resist underlayer film. The photoresist layer can be formed by a well-known method, i.e., by coating a photoresist composition solution on the underlayer film and baking it. The photoresist film thickness is, for example, 50 to 10,000 nm, or 100 to 2,000 nm, or 200 to 1,000 nm.

[0086] The photoresist formed on the resist underlayer film is not particularly limited as long as it is sensitive to the light used for exposure. Both negative and positive photoresists can be used. Examples include positive photoresists composed of a novolak resin and a 1,2-naphthoquinone diazide sulfonic acid ester; chemically amplified photoresists composed of a binder having a group that decomposes in the presence of acid to increase the alkaline dissolution rate and a photoacid generator; chemically amplified photoresists composed of a low-molecular-weight compound that decomposes in the presence of acid to increase the alkaline dissolution rate of the photoresist, an alkali-soluble binder, and a photoacid generator; and chemically amplified photoresists composed of a binder having a group that decomposes in the presence of acid to increase the alkaline dissolution rate of the photoresist, a low-molecular-weight compound that decomposes in the presence of acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator. Examples include APEX-E (trade name) manufactured by Shipley Chemical Co., Ltd., PAR710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and SEPR430 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. Further examples include fluorine-containing polymer photoresists such as those described in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0087] Next, a resist pattern is formed by irradiation with light or electron beams and development. First, exposure is performed through a predetermined mask. Near ultraviolet, far ultraviolet, or extreme ultraviolet (e.g., EUV (wavelength 13.5 nm)) is used for exposure. Specifically, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F2 excimer laser (wavelength 157 nm) can be used. Among these, ArF excimer laser (wavelength 193 nm) and EUV (wavelength 13.5 nm) are preferred. After exposure, post-exposure bake can also be performed as needed. The post-exposure bake is performed under conditions appropriately selected from a heating temperature of 70°C to 150°C and a heating time of 0.3 to 10 minutes.

[0088] In addition, in the present invention, a resist for electron beam lithography can be used instead of a photoresist. Either a negative or positive type electron beam resist can be used. Examples of such resists include chemically amplified resists consisting of an acid generator and a binder having a group that decomposes in the presence of acid to change the alkaline dissolution rate; chemically amplified resists consisting of an alkali-soluble binder, an acid generator, and a low-molecular-weight compound that decomposes in the presence of acid to change the alkaline dissolution rate of the resist; chemically amplified resists consisting of an acid generator, a binder having a group that decomposes in the presence of acid to change the alkaline dissolution rate, and a low-molecular-weight compound that decomposes in the presence of acid to change the alkaline dissolution rate of the resist; non-chemically amplified resists consisting of a binder having a group that decomposes in the presence of an electron beam to change the alkaline dissolution rate; and non-chemically amplified resists consisting of a binder having a moiety that is cleaved by an electron beam to change the alkaline dissolution rate. When using these electron beam resists, resist patterns can be formed in the same manner as when using a photoresist using an electron beam as the irradiation source.

[0089] Next, development is carried out with a developer, whereby, for example, when a positive photoresist is used, the photoresist in the exposed portion is removed, and a photoresist pattern is formed. Examples of the developer include aqueous alkaline solutions such as aqueous solutions of alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, and aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine. Furthermore, surfactants and the like can also be added to these developers. Development conditions are appropriately selected from a temperature of 5 to 50°C and a time of 10 to 600 seconds.

[0090] Then, the inorganic lower layer film (middle layer) is removed using the photoresist (upper layer) pattern thus formed as a protective film, and then the organic lower layer film (lower layer) is removed using the film consisting of the patterned photoresist and inorganic lower layer film (middle layer) as a protective film. Finally, the semiconductor substrate is processed using the patterned inorganic lower layer film (middle layer) and organic lower layer film (lower layer) as protective films.

[0091] First, the inorganic underlayer film (intermediate layer) in the area where the photoresist was removed is removed by dry etching to expose the semiconductor substrate. Gases such as tetrafluoromethane (CF), perfluorocyclobutane (C), perfluoropropane (C), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, chlorine trifluoride, chlorine, trichloroborane, and dichloroborane can be used for dry etching of the inorganic underlayer film. A halogen-based gas is preferably used for dry etching of the inorganic underlayer film, and a fluorine-based gas is more preferred. Examples of fluorine-based gases include tetrafluoromethane (CF), perfluorocyclobutane (C), perfluoropropane (C), trifluoromethane, and difluoromethane (CH).

[0092] Thereafter, the organic underlayer film is removed using the patterned photoresist and inorganic underlayer film as a protective film. The organic underlayer film (underlayer) is preferably removed by dry etching using an oxygen-based gas. This is because inorganic underlayer films containing a large amount of silicon atoms are difficult to remove by dry etching using an oxygen-based gas.

[0093] Finally, the semiconductor substrate is processed, preferably by dry etching using a fluorine-based gas. Examples of fluorine-based gases include tetrafluoromethane (CF4), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, and difluoromethane (CH2F2).

[0094] Furthermore, an organic antireflective coating can be formed on the resist underlayer coating before the formation of the photoresist. The antireflective coating composition used therein is not particularly limited, and any one can be selected from those conventionally used in lithography processes. The antireflective coating can be formed by a conventional method, such as coating with a spinner or coater and baking.

[0095] In the present invention, an organic underlayer film is formed on a substrate, and then an inorganic underlayer film is formed thereon, and a photoresist is then coated on top of that. This narrows the pattern width of the photoresist, and even if a thin layer of photoresist is applied to prevent pattern collapse, the substrate can be processed by selecting an appropriate etching gas. For example, a fluorine-based gas that has a sufficiently high etching rate for the photoresist can be used as an etching gas to process the resist underlayer film, and a fluorine-based gas that has a sufficiently high etching rate for the inorganic underlayer film can be used as an etching gas to process the substrate, and an oxygen-based gas that has a sufficiently high etching rate for the organic underlayer film can be used as an etching gas to process the substrate.

[0096] The resist underlayer film formed from the resist underlayer film-forming composition may also absorb light depending on the wavelength of the light used in the lithography process. In such cases, it can function as an antireflective film that prevents light from being reflected from the substrate. Furthermore, the underlayer film formed from the resist underlayer film-forming composition of the present invention can also function as a hard mask. The underlayer film of the present invention can also be used as a layer for preventing interaction between the substrate and the photoresist, a layer having the function of preventing adverse effects on the substrate of materials used in the photoresist or substances generated during exposure of the photoresist, a layer having the function of preventing diffusion of substances generated from the substrate during heating and baking into an upper photoresist layer, and a barrier layer for reducing the poisoning effect of the photoresist layer due to a dielectric layer of the semiconductor substrate.

[0097] In addition, an underlayer film formed from the resist underlayer film-forming composition can be applied to a substrate having via holes formed therein for use in a dual damascene process, and can be used as a filling material capable of filling the holes without gaps. It can also be used as a planarizing material for planarizing the surface of an uneven semiconductor substrate. [Example]

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The apparatus used to measure the weight-average molecular weight of the compounds obtained in the following synthesis examples is shown below. Apparatus: Tosoh Corporation HLC-8320GPC GPC column: TSKgel Super-MultiporeHZ-N (2 columns) Column temperature: 40℃ Flow rate: 0.35mL / min Eluent:THF Standard sample: polystyrene

[0099] <Synthesis Example 1> A flask was charged with 10.00 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 4.17 g of 1-naphthaldehyde (Tokyo Chemical Industry Co., Ltd.), 1.28 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 23.18 g of propylene glycol monomethyl ether acetate (PGMEA). The mixture was then heated to reflux under nitrogen and reacted for approximately 15 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-1). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 450. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0100] [ka]

[0101] <Synthesis Example 2> 8.00 g of α-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 3.18 g of 1-naphthaldehyde (Tokyo Chemical Industry Co., Ltd.), 0.98 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), 4.00 g of NMP, and 18.24 g of PGMEA were added. The mixture was then heated to reflux under nitrogen and reacted for approximately 15 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-2). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 450. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0102] [ka]

[0103] <Synthesis Example 3> A flask was charged with 5.00 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 3.07 g of 1-pyrenecarboxaldehyde, 0.64 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 13.07 g of PGMEA. The mixture was then heated to reflux under nitrogen and allowed to react for approximately 15 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-3). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 520. The resulting compound was dissolved in cyclohexanone and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0104] [ka]

[0105] <Synthesis Example 4> A flask was charged with 5.00 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 2.41 g of 9-fluorenone (Tokyo Chemical Industry Co., Ltd.), 0.64 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 12.07 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for approximately 15 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-4). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 800. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0106] [ka]

[0107] <Synthesis Example 5> A flask was charged with 8.00 g of α-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 3.67 g of 9-fluorenone (Tokyo Chemical Industry Co., Ltd.), 1.96 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), 1.36 g of NMP, and 12.27 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for approximately 15 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-5). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 470. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0108] [ka]

[0109] <Synthesis Example 6> A flask was charged with 4.67 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 5.00 g of carbazole (Tokyo Chemical Industry Co., Ltd.), 1.44 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 16.66 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for approximately 9 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-6). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 3,550. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0110] [ka]

[0111] <Synthesis Example 7> A flask was charged with 3.56 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 5.00 g of N-phenyl-1-naphthylamine (Tokyo Chemical Industry Co., Ltd.), 1.10 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 14.48 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for 22 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (1-7). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 1,450. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0112] [ka]

[0113] <Synthesis Example 8> A flask was charged with 9.69 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 5.00 g of 2-phenylindole (Tokyo Chemical Industry Co., Ltd.), 1.24 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 23.90 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for 21 hours. After the reaction was stopped, the mixture was precipitated with methanol and water and dried to obtain compound (1-8). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 1,000. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0114] [ka]

[0115] <Synthesis Example 9> A flask was charged with 9.05 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 4.50 g of 2,2'-biphenol, 1.16 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 22.07 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for 21 hours. After the reaction was stopped, the mixture was precipitated with methanol and water and dried to obtain compound (1-9). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 900. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0116] [ka]

[0117] <Synthesis Example 10> A flask was charged with 10.52 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 4.50 g of 1,5-dihydroxynaphthalene (Tokyo Chemical Industry Co., Ltd.), 1.35 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 24.55 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for 21 hours. After the reaction was stopped, the mixture was precipitated with methanol and water and dried to obtain compound (1-10). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 600. The resulting compound was dissolved in propylene glycol monomethyl ether (hereinafter referred to as PGME) and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0118] [ka]

[0119] <Synthesis Example 11> A flask was charged with 7.48 g of p-naphtholbenzein (Fujifilm Wako Pure Chemical Industries, Ltd.), 7.00 g of 9,9-bis(4-hydroxyphenyl)fluorene (Tokyo Chemical Industry Co., Ltd.), 0.96 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 23.16 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for 21 hours. After the reaction was stopped, the mixture was precipitated with methanol and water and dried to obtain compound (1-11). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 800. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0120] [ka]

[0121] <Comparative Synthesis Example 1> A flask was charged with 15.00 g of 2,2'-biphenol (Tokyo Chemical Industry Co., Ltd.), 12.58 g of 1-naphthaldehyde (Tokyo Chemical Industry Co., Ltd.), 1.94 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 29.58 g of PGMEA. The mixture was then heated to reflux under nitrogen and allowed to react for approximately 14 hours. After the reaction was stopped, the mixture was precipitated with methanol and dried to obtain compound (2-1). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 5,500. The resulting compound was dissolved in PGME and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0122] [ka]

[0123] <Comparative Synthesis Example 2> A flask was charged with 10.00 g of 2,2'-biphenol (Tokyo Chemical Industry Co., Ltd.), 9.68 g of 9-fluorenone (Tokyo Chemical Industry Co., Ltd.), 2.58 g of methanesulfonic acid (Tokyo Chemical Industry Co., Ltd.), and 33.39 g of PGMEA. The mixture was then heated to reflux under nitrogen and reacted for approximately 12.5 hours. After the reaction was stopped, the mixture was precipitated with methanol and water and dried to obtain compound (2-2). The weight-average molecular weight (Mw) measured by GPC in terms of polystyrene was 1,700. The resulting compound was dissolved in PGMEA and subjected to ion exchange using a cation exchange resin and an anion exchange resin for 4 hours to obtain a solution of the target compound.

[0124] [ka]

[0125] Example 1 A compound solution (solid content 20.96% by mass) was obtained in Synthesis Example 1. To 6.20 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 7.85 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0126] <Example 2> A compound solution (solid content 13.88% by mass) was obtained in Synthesis Example 2. To 8.78 g of this compound solution, 0.24 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.83 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.12 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 0.42 g of PGMEA, 0.91 g of PGME, and 2.70 g of cyclohexanone were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0127] Example 3 A compound solution (solid content 15.50% by mass) was obtained in Synthesis Example 3. To 8.39 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 7.23 g of PGMEA, 1.77 g of PGME, and 0.27 g of cyclohexanone were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0128] Example 4 A compound solution (solid content 13.82% by mass) was obtained in Synthesis Example 4. To 9.40 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 4.65 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0129] <Example 5> A compound solution (solid content 16.39% by mass) was obtained in Synthesis Example 5. To 7.43 g of this compound solution, 0.24 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.83 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.12 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 0.41 g of PGMEA, 0.91 g of PGME, and 4.05 g of cyclohexanone were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0130] Example 6 A compound solution (solid content 14.09% by mass) was obtained in Synthesis Example 6. To 9.22 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 4.83 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0131] Example 7 A compound solution (solid content 12.37% by mass) was obtained in Synthesis Example 7. To 9.19 g of this compound solution, 0.23 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.71 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.11 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 4.85 g of PGMEA, and 3.91 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0132] Example 8 A compound solution (solid content 17.46% by mass) was obtained in Synthesis Example 8. To 7.44 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 6.61 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0133] Example 9 A compound solution (solid content 18.75% by mass) was obtained in Synthesis Example 9. To 6.93 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 7.12 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0134] Example 10 A compound solution (solid content 18.01% by mass) was obtained in Synthesis Example 10. To 7.22 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 5.39 g of PGMEA, and 5.05 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0135] Example 11 A compound solution (solid content 18.50% by mass) was obtained in Synthesis Example 11. 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 7.03 g of PGMEA, and 3.61 g of PGME were added to 7.03 g of this compound solution and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0136] <Comparative Example 1> A compound solution (solid content 22.44% by mass) was obtained in Comparative Synthesis Example 1. To 5.79 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 5.39 g of PGMEA, and 6.48 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0137] <Comparative Example 2> A compound solution (solid content 19.00% by mass) was obtained in Comparative Synthesis Example 1. To 6.84 g of this compound solution, 0.26 g of TMOM-BP (manufactured by Honshu Chemical Co., Ltd.), 1.95 g of PGME containing 2% by mass of pyridinium p-hydroxybenzenesulfonate, 0.13 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 7.21 g of PGMEA, and 3.61 g of PGME were added and dissolved, and the mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0138] (Test for elution into resist solvent) The solutions of the resist underlayer film-forming compositions prepared in Comparative Examples 1-2 and Examples 1-11 were each applied to a silicon wafer using a spin coater and baked on a hot plate at 350°C for 60 seconds to form resist underlayer films (thickness: 150 nm). These resist underlayer films were then immersed in a general-purpose thinner, PGME / PGMEA = 7 / 3. The resist underlayer films were insoluble, confirming sufficient curability.

[0139] (Optical constant measurement) The resist underlayer film-forming composition solutions prepared in Comparative Example 1-2 and Examples 1-11 were each applied to a silicon wafer using a spin coater. The resist underlayer films were baked on a hot plate at 350°C for 60 seconds to form resist underlayer films (film thickness 50 nm). The refractive index (n value) and optical extinction coefficient (k value, also called extinction coefficient) of these resist underlayer films at a wavelength of 193 nm were measured using a spectroscopic ellipsometer (Table 1).

[0140] [Table 1]

[0141] Comparing Comparative Example 1 with Example 1, and Comparative Example 2 with Examples 4 and 9, it is possible to increase the n value in the Examples. Also, as in the other Examples, the optical constants can be significantly changed by changing the type of compound to be combined.

[0142] [Dry etching rate measurement] The etcher and etching gas used for measuring the dry etching rate are as follows: RIE-10NR (Samco): CF4 The resist underlayer film-forming composition solutions prepared in Comparative Example 1-2 and Examples 1-11 were each applied to a silicon wafer using a spin coater. The resist underlayer film (150 nm thick) was formed by baking on a hot plate at 350°C for 60 seconds. The dry etching rates were measured using CF4 gas as the etching gas, and the dry etching rate ratios for Comparative Example 1-2 and Examples 1-11 were calculated. The dry etching rate ratio is the dry etching rate ratio of (resist underlayer film) / (KrF photoresist) (Table 2).

[0143] [Table 2]

[0144] Comparing Comparative Example 1 with Example 1, and Comparative Example 2 with Example 4 and Example 9, the Examples show a higher etching rate. Also, as in the other examples, the etching resistance can be significantly changed by changing the type of compound to be combined.

[0145] (Embeddability evaluation) The embedding ability was confirmed in a dense pattern area of ​​a 200 nm thick SiO2 substrate with a trench width of 50 nm and a pitch of 100 nm. The resist underlayer film-forming compositions prepared in Comparative Examples 1-2 and Examples 1-11 were applied to the substrate and then baked at 350°C for 60 seconds to form a resist underlayer film of approximately 150 nm. The planarization of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the presence or absence of the resist underlayer film-forming composition filling the interior of the pattern was confirmed (Table 3).

[0146] [Table 3]

[0147] The examples exhibit high embedding properties similar to those of conventional materials. [Industrial Applicability]

[0148] According to the present invention, there is provided a resist underlayer film-forming composition that exhibits high etching resistance, a good dry etching rate ratio and optical constants, has good coverage even on uneven substrates, has small film thickness differences after filling, and is capable of forming a flat film. The present invention also provides a method for producing a polymer suitable for the resist underlayer film-forming composition, a resist underlayer film using the resist underlayer film-forming composition, and a method for producing a semiconductor device.

Claims

1. A resist underlayer film-forming composition comprising a reaction product of an aromatic compound (A) having 6 to 120 carbon atoms and a compound represented by the following formula (1), and a solvent, wherein one carbon atom in ring Y is linked to one of the aromatic compounds (A), and one carbon atom in Ar 1 or Ar 2 is linked to another of the aromatic compounds (A): 【Chemistry 1】 [In formula (1), Z represents —(C═O)— or —C(—OH)—, and Ar １ and Ar ２ each independently represents an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic group, an optionally substituted aromatic group, or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.

2. The resist underlayer film forming composition according to claim 1, wherein the compound represented by formula (1) is represented by the following formula (1a): 【Chemistry 2】 [In formula (1a), Z represents —(C═O)—, Ar 1 and Ar 2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic group or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.]

3. A resist underlayer film-forming composition comprising a reaction product of an aromatic compound (A) having 6 to 120 carbon atoms and a compound represented by the following formula (1), and a solvent, wherein one carbon atom in ring Y of the reaction product is linked to two of the aromatic compounds (A): 【Transformation 3】 [In formula (1), Z represents —(C═O)— or —C(—OH)—; Ar 1 and Ar 2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group; and ring Y represents an optionally substituted cyclic aliphatic group, an optionally substituted aromatic group, or a fused ring of an optionally substituted cyclic aliphatic group and an aromatic group.] 4. The resist underlayer film forming composition according to claim 3, wherein ring Y in formula (1a) is a fused ring structure containing a cyclohexene ring.

5. The resist underlayer film forming composition according to claim 4, wherein in formula (1a), ring Y represents a condensed ring of a cyclic aliphatic and an aromatic ring.

6. A resist underlayer film forming composition according to claim 1 or 2, wherein the compound represented by formula (1) is represented by the following formula (1b): 【Chemistry 4】 [In formula (1b), Z represents —C(—OH)—, Ar 1 and Ar 2 each independently represent an optionally substituted phenyl, naphthyl, anthracenyl, or pyrenyl group, and ring Y represents an optionally substituted cyclic aliphatic, an optionally substituted aromatic, or a fused ring of an optionally substituted cyclic aliphatic and an aromatic.] 7. The resist underlayer film forming composition according to claim 6, wherein the compound represented by formula (1b) is an aromatic compound.

8. The resist underlayer film forming composition according to claim 7, wherein in formula (1b), Y contains a naphthalene ring.

9. The resist underlayer film forming composition according to claim 1, wherein in formula (1), Ar 1 and Ar 2 each independently represent a phenyl or naphthyl group optionally substituted with a hydroxy group.

10. The resist underlayer film forming composition according to claim 1, wherein the aromatic compound (A) contains one or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or combinations thereof.

11. The resist underlayer film forming composition according to claim 1, wherein the aromatic compound (A) contains two or more benzene rings, naphthalene rings, anthracene rings, pyrene rings, or a combination thereof.

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

13. A resist underlayer film forming composition according to any one of claims 1 to 12, further comprising an acid and / or an acid generator.

14. A resist underlayer film forming composition according to any one of claims 1 to 13, wherein the boiling point of the solvent is 160°C or higher.

15. A resist underlayer film, which is a fired product of a coating film made of the resist underlayer film forming composition according to any one of claims 1 to 14.

16. A method for manufacturing a semiconductor device, comprising the steps of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film forming composition described in any one of claims 1 to 14, forming a resist film thereon, forming a resist pattern by irradiating with light or an electron beam and developing, etching the underlayer film using the resist pattern, and processing a semiconductor substrate using the patterned underlayer film.

17. A method for manufacturing a semiconductor device as described in claim 16, wherein the step of forming a resist underlayer film is carried out by a nanoimprint method.

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