Resist underlayer film formation composition

Abstract

A resist underlayer film formation composition according to the present invention includes a solvent and a compound P that includes a fluorene skeleton and also includes a partial structure that has, on one aromatic hydrocarbon ring, a phenolic hydroxyl group and a total of two groups selected from a hydroxymethyl group and groups formed by substituting the hydrogen atom of the hydroxyl group of a hydroxymethyl group with a substituent.

Description

Resist underlayer film-forming composition

[0001] The present invention relates to a resist underlayer film-forming composition, a resist underlayer film that is a fired product of a coating film made of the composition, and a method for manufacturing a semiconductor device using the composition.

[0002] In the manufacture of semiconductor devices, microfabrication is performed by a lithography process. In this lithography process, when a resist layer on a substrate is exposed to an ultraviolet laser such as a KrF excimer laser or an ArF excimer laser, a known problem occurs in that a resist pattern having a desired shape cannot be formed due to the influence of standing waves generated by reflection of the ultraviolet laser on the substrate surface. To solve this problem, a resist underlayer film (anti-reflective film) is provided between the substrate and the resist layer. It is known that a novolac resin is used as a composition for forming the resist underlayer film.

[0003] Also, in order to achieve thinner resist layers as the resist patterns become finer, a lithography process is known in which at least two resist underlayer films are formed and used as a mask material. Materials for forming the at least two layers include organic resins (e.g., acrylic resins, novolac resins), silicon resins (e.g., organopolysiloxanes), inorganic silicon compounds (e.g., SiON, SiO ２ When dry etching is performed using the pattern formed from the organic resin layer as a mask, the pattern must be resistant to etching gas (for example, fluorocarbon).

[0004] As a composition for forming such a resist underlayer film, for example, Patent Document 1 discloses a resist underlayer film-forming composition containing a novolak resin and a compound having a phenolic hydroxyl group and a hydroxymethyl group on a benzene ring added as a crosslinking agent.

[0005] International Publication No. 2014 / 208542

[0006] However, conventional resist underlayer film-forming compositions still have some shortcomings in terms of requirements such as reduction in the amount of sublimation that contaminates equipment, etching resistance in substrate processing, and particularly hump suppression (suppression of the formation of bump-like protrusions called humps).

[0007] The present invention solves the above-mentioned problems. Specifically, the present invention includes the following: [1] A resist underlayer film-forming composition comprising: a compound P having a fluorene skeleton and a partial structure having, on one aromatic hydrocarbon ring, a phenolic hydroxyl group and a total of two groups selected from a hydroxymethyl group and a group in which the hydrogen atom of the hydroxy group of the hydroxymethyl group is substituted with a substituent; and a solvent. [2] The resist underlayer film-forming composition according to [1], wherein the compound P is a compound represented by the following formula (1): (In formula (1), Ar １ represents a benzene ring, a naphthalene ring, or a biphenyl ring, each of which may have a substituent; Ar ２each independently represent a benzene ring or a naphthalene ring, and each R independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxyalkyl group having 2 to 6 carbon atoms.) [3] The resist underlayer film-forming composition according to [1] or [2], wherein the content of the compound P is 90 mass% or more based on the total solid content of the composition. [4] The resist underlayer film-forming composition according to [2], wherein all R in formula (1) are hydrogen atoms. [5] The resist underlayer film-forming composition according to any of [1] to [4], further comprising at least one of an acid and an acid generator. [6] The resist underlayer film-forming composition according to any of [1] to [5], further comprising a surfactant. [7] The resist underlayer film-forming composition according to any of [1] to [6], wherein the solvent comprises a solvent having a boiling point of 160°C or higher. [8] A resist underlayer film, which is a baked product of a coating film comprising the resist underlayer film-forming composition according to any of [1] to [7]. [9] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to [7]; a step of forming a resist film on the formed resist underlayer film; a step of forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; a step of etching the resist underlayer film through the formed resist pattern to form a patterned resist underlayer film; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[10] A method for manufacturing a semiconductor device, comprising: a step of forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to any one of [1] to [7]; a step of forming a hard mask on the formed resist underlayer film; a step of forming a resist film on the formed hard mask; a step of forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; a step of etching the hard mask through the formed resist pattern to form a patterned hard mask; and a step of etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0008] According to the present invention, there is provided a novel resist underlayer film-forming composition that meets the requirements for reducing the amount of sublimation that contaminates equipment, and for improving etching resistance in substrate processing, particularly for suppressing hump formation, while also maintaining other favorable properties.

[0009] [Resist Underlayer Film-Forming Composition] The resist underlayer film-forming composition according to the present invention comprises a compound P having a partial structure that includes a fluorene skeleton and has, on one aromatic hydrocarbon ring, a phenolic hydroxyl group and two groups selected from a hydroxymethyl group and a group in which the hydrogen atom of the hydroxy group of the hydroxymethyl group is substituted with a substituent, and a solvent. From the viewpoint of reducing the amount of sublimation and obtaining a resist underlayer film that is excellent in hump suppression, the compound P is preferably contained in an amount of 90% by mass or more, more preferably 95% by mass or more, and most preferably 100% by mass, based on the total solid content in the composition.

[0010] [Compound P] Compound P includes a fluorene skeleton and a partial structure. The partial structure has a phenolic hydroxyl group and two groups on one aromatic hydrocarbon ring. The two groups are selected from a hydroxymethyl group and a group in which the hydrogen atom of the hydroxyl group of the hydroxymethyl group is substituted with a substituent. The number of phenolic hydroxyl groups on one aromatic hydrocarbon ring is not particularly limited and may be one or two or more, but one is preferred.

[0011] More specifically, compound P is a compound represented by the following formula (1): (In formula (1), Ar １ represents a benzene ring, a naphthalene ring, or a biphenyl ring, each of which may have a substituent; Ar ２ each independently represents a benzene ring or a naphthalene ring, and each R independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxyalkyl group having 2 to 6 carbon atoms.

[0012] RO-CH in formula (1) ２ The - group is an example of a hydroxymethyl group or a group in which the hydrogen atom of the hydroxy group of a hydroxymethyl group is substituted with a substituent. ２ In formula (1), one Ar ２ is two RO-CH ２ In formula (1), one Ar ２ Two RO-CH bonds to ２ At least one of the Ar - groups is bonded to a carbon atom at the ortho position relative to the carbon atom to which the phenolic hydroxyl group is bonded. ２ Two RO-CH bonds to ２ One of the Ar - groups may be bonded to a carbon atom at the para position to the carbon atom to which the phenolic hydroxyl group is bonded. ２ Two RO-CH bonds to ２ It is preferred that both of the - groups are bonded to the carbon atom at the ortho position to the carbon atom to which the phenolic hydroxyl group is bonded.

[0013] Ar in formula (1) １ Ar in formula (1) constitutes a fluorene skeleton. １ is a benzene ring, a naphthalene ring, or a biphenyl ring, and is represented by the following formula (2).

[0014] Ar in formula (1) １ As the ring, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable.

[0015] Ar in formula (1) １ Examples of the substituent that may be substituted include an alkyl group having 1 to 4 carbon atoms, a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0016] Ar in formula (1) ２ As the ring, a benzene ring is preferred.

[0017] Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, and a 2-methyl-cyclopropyl group.

[0018] The alkoxyalkyl group having 2 to 6 carbon atoms may be linear, branched, or cyclic, and examples thereof include an ethoxy group, an i-propoxy group, an n-pentyloxy group, an n-hexyloxy group, a cyclohexyloxy group, etc. An example of an alkoxyalkyl group having 2 to 6 carbon atoms is a group represented by the following formula (3): (In formula (3), R １０２ represents a methyl group or an ethyl group. * represents a bond.

[0019] In formula (1), at least one R is preferably a hydrogen atom, and more preferably all R are hydrogen atoms.

[0020] Examples of compound P include, but are not limited to, the following compounds: (In the formula, R has the same meaning as R in formula (1).)

[0021] For example, compound P can be synthesized by reacting a compound represented by the following formula (4) with formaldehyde in an aqueous solution in the presence of a base. If necessary, a methoxymethyl group can be introduced by further reacting with a compound that reacts with a hydroxymethyl group to give a methoxymethyl group. (In formula (4), Ar １ , Ar ２ is synonymous with formula (1).

[0022] [Solvent] The resist underlayer film forming composition of the present invention can be prepared by dissolving the above-mentioned compound P in an appropriate solvent, and is used in the form of a homogeneous solution.

[0023] Examples of such solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, methyl cellosolve acetate, ethyl cellosolve acetate, 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, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0024] Furthermore, a high boiling point solvent having a boiling point of 180° C. or higher can also be used. Specific examples of high boiling point organic solvents include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, triethylene Glycol diacetate, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the alkyl acrylate include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate.

[0025] These solvents can be used alone or in combination of two or more. The solid content of the composition excluding the organic solvent is, for example, 0.5 to 30% by mass, preferably 0.8 to 15% by mass.

[0026] In addition, the following compounds described in WO2018 / 131562A1 can also be used. (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 from each other and may be bonded to each other to form a ring structure.

[0027] Examples of the alkyl group having 1 to 20 carbon atoms include linear or branched alkyl groups which may or may not have a substituent, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, an n-octyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-nonyl group, an isononyl group, a p-tert-butylcyclohexyl group, an n-decyl group, an n-dodecylnonyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an 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.

[0028] Examples of the alkyl group having 1 to 20 carbon atoms interrupted by an oxygen atom, a sulfur atom, or an amide bond include the structural unit -CH ２—O—, —CH ２ -S-, -CH ２ -NHCO- or -CH ２ Examples include those containing -CONH-. -O-, -S-, -NHCO- or -CONH- may be present in one unit or two or more units in the alkyl group. Specific examples of the alkyl group having 1 to 20 carbon atoms interrupted by an -O-, -S-, -NHCO- or -CONH- unit include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a methylcarbonylamino group, an ethylcarbonylamino group, a propylcarbonylamino group, a butylcarbonylamino group, a methylaminocarbonyl group, an ethylaminocarbonyl group, a propylaminocarbonyl group, a butylaminocarbonyl group, a methylaminocarbonyl group, a propylaminocarbonyl group, a butylaminocarbonyl group, a methylaminocarbonyl group, a propylaminocarbonyl group, a butylaminocarbonyl group, a methylaminocarbonyl group, a propylaminocarbonyl group, a propylaminocarbonyl group, a methylaminocarbonyl group, a propylaminocarbonyl group, a propylaminocarbonyl group, a butylaminocarbonyl group, a methylaminocarbonyl group, a propyl ... 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.

[0029] 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.

[0030] Specific examples of preferred compounds represented by formula (i) are shown below.

[0031] Among the above, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, and Compounds represented by formula (i) are preferably 3-methoxy-N,N-dimethylpropionamide and N,N-dimethylisobutyramide.

[0032] These solvents can be used alone or in combination of two or more. Among these solvents, 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) are preferred. Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and N,N-dimethylisobutyramide are particularly preferred. Among these solvents, those having a boiling point of 160°C or higher are preferred.

[0033] [Optional Components] The resist underlayer film-forming composition of the present invention may further contain, as an optional component, at least one of an acid and / or acid generator, a thermal acid generator, and a surfactant.

[0034] (Acid and / or Acid Generator) The resist underlayer film forming composition according to the present invention may contain an acid and / or an acid generator.

[0035] Examples of acids include carboxylic acid compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, pyridinium phenolsulfonic 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, as well as inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. A single acid may be used, or two or more acids may be used in combination. The amount of the acid added is usually 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 5% by mass, based on the total solids content.

[0036] Examples of the acid generator include thermal acid generators and photoacid generators, such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, TAG-2689, and TAG-2700 (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 organic alkyl sulfonates.

[0037] Examples of the photoacid generator include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds. Examples of the onium salt compounds 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.

[0038] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0039] 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.

[0040] The acid generator may be used alone or in combination of two or more thereof. When an acid generator is used, the proportion thereof is 0.01 to 10 parts by mass, or 0.1 to 8 parts by mass, or 0.5 to 5 parts by mass, relative to 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0041] (Surfactant) The resist underlayer film forming composition of the present invention may further contain a surfactant. 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 octylphenyl ether and polyoxyethylene nonylphenyl 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, and polyoxyethylene sorbitan monostearate. Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; Eftop (registered trademark) EF301, EF303, and EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.); Megafac (registered trademark) F171, F173, R-30, R-30-N, R-40, and R-4 Examples of suitable surfactants include fluorine-based surfactants such as O-LM (manufactured by DIC Corporation), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited), Asahiguard (registered trademark) AG710, Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). One surfactant selected from these surfactants may be added, or two or more surfactants may be added in combination. The content of the surfactant is, for example, 0.01 to 5% by mass, based on the solids content of the resist underlayer film-forming composition of the present invention, excluding the solvent described below.

[0042] (Light absorber) Examples of the light absorber include commercially available light absorbers described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as C.I. Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114 and 124; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72 and 73; C.I. C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 96; C.I. Fluorescent Brightening Agent 112, 135, and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; C.I. Pigment Green 10; C.I. Pigment Brown 2. The light-absorbing agent is usually 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 underlayer film-forming composition.

[0043] (Rheology Adjuster) The rheology adjuster is mainly added 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 filling ability of the resist underlayer film-forming composition into 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 adjusters are usually blended in an amount of less than 30% by mass based on the total solids content of the resist underlayer film-forming composition.

[0044] (Adhesion aid) The adhesion aid 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 peeling of the resist 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 methyltrimethylsilane. Examples of suitable adhesion aids 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 aids 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 underlayer film-forming composition.

[0045] 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 polymer 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.

[0046] 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.

[0047] 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, but PTFE (polytetrafluoroethylene) is preferred.

[0048] [Resist Underlayer Film] A resist underlayer film can be formed using the resist underlayer film-forming composition of the present invention as follows. 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 / silicon dioxide-coated substrate, a silicon nitride substrate, a glass substrate, an ITO substrate, a polyimide substrate, or a low-dielectric-constant material (low-k material)-coated substrate) by an appropriate application method such as a spinner or coater, and then baked using a heating means such as a hot plate to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 80°C to 600°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 350°C and the baking time is 0.5 to 2 minutes. Air may be used as the atmospheric gas during baking, or an inert gas such as nitrogen or argon may also be used. Baking may be performed by changing the temperature and baking time between the first and second stages. 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. Furthermore, if a quartz substrate is used as the substrate, a replica of a quartz imprint mold (mold replica) can be produced.

[0049] Furthermore, an adhesion layer and / or a silicone layer containing 99% by mass or less, or 50% by mass or less of Si can be formed on the resist underlayer film of the present invention by coating or vapor deposition. For example, the adhesion layer described in JP-A-2013-202982 and Japanese Patent No. 5827180, or the silicon-containing resist underlayer film (inorganic resist underlayer film)-forming composition described in WO 2009 / 104552 A1 can be formed by spin coating, or a Si-based inorganic material film can be formed by CVD or the like.

[0050] 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, it is possible to form a resist underlayer film in which the step between the portion with a step and the portion without a step is in the range of 3 to 70 nm.

[0051] [Method for manufacturing a semiconductor device] The method for manufacturing a semiconductor device according to the present invention includes: a step of forming a resist underlayer film using the resist underlayer film-forming composition according to the present invention; a step of forming a resist film on the formed resist underlayer film; a step of forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; a step of etching the resist underlayer film through the formed resist pattern to form a patterned resist underlayer film; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0052] Furthermore, a method for manufacturing a semiconductor device according to the present invention includes: a step of forming a resist underlayer film using the resist underlayer film-forming composition according to the present invention; a step of forming a hard mask on the formed resist underlayer film; a step of forming a resist film on the formed hard mask; a step of forming a resist pattern by irradiating the formed resist film with light or an electron beam and developing it; a step of etching the hard mask through the formed resist pattern to form a patterned hard mask; a step of etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and a step of processing a semiconductor substrate through the patterned resist underlayer film.

[0053] The step of forming a resist underlayer film using the resist underlayer film-forming composition according to the present invention is as described above.

[0054] An organopolysiloxane film may be formed as a second resist underlayer film on the resist underlayer film formed by the above process, and a resist pattern may be formed thereon. This second resist underlayer film may be a SiON film or a SiN film formed by a vapor deposition method such as CVD or PVD. Furthermore, an antireflective coating (BARC) may be formed as a third resist underlayer film on the second resist underlayer film, and the third resist underlayer film may be a resist shape correction film without antireflective properties.

[0055] In the step of forming the resist pattern, exposure is performed through a mask (reticle) for forming a predetermined pattern or by direct writing. Examples of exposure sources that can be used include g-line, i-line, KrF excimer laser, ArF excimer laser, EUV, and electron beam. After exposure, post-exposure baking is performed as needed. The resist is then developed with a developer (e.g., a 2.38% by mass aqueous solution of tetramethylammonium hydroxide), and then rinsed with a rinse solution or pure water to remove the used developer. Post-baking is then performed to dry the resist pattern and enhance adhesion to the underlayer.

[0056] The etching process performed after the resist pattern formation is performed by dry etching. The etching gas used for the dry etching is, for example, CHF 2 O 3 for the second resist underlayer film (organopolysiloxane film). ３ , C.F. ４ , C ２ F ６ For the first resist underlayer film formed from the resist underlayer film-forming composition of the present invention, for example, O ２ , N ２ O, NO ２ For surfaces having steps or recesses and / or protrusions, for example, CHF ３ , C.F. ４ , C ２ F ６ Furthermore, these gases may be mixed with argon, nitrogen or carbon dioxide.

[0057] [Formation of Resist Underlayer Film by Nanoimprinting] The step of forming the resist underlayer film can also be performed by nanoimprinting, which includes the steps of applying a curable composition onto the formed resist underlayer film, bringing the curable composition into contact with a mold, irradiating the curable composition with light or an electron beam to form a cured film, and separating the cured film from the mold.

[0058] In the mold release process of photo-nanoimprint technology, adhesion between the resist composition and the substrate is important. If the adhesion between the resist composition and the substrate is low, when the mold is released in the mold release process, part of the photocured product obtained by curing the resist composition may peel off while still adhering to the mold, resulting in pattern peeling defects. As a technique for improving adhesion between the resist composition and the substrate, a technique has been proposed in which an adhesion layer is formed between the resist composition and the substrate, which is a layer for adhering the resist composition to the substrate.

[0059] In addition, a highly etch-resistant layer may be used for pattern formation in nanoimprinting. Organic materials and silicone materials are commonly used as materials for the highly etch-resistant layer. Furthermore, an adhesion layer or a silicon-containing silicone layer can be formed on the nanoimprint resist underlayer film by coating or vapor deposition. When these adhesion layers or silicon-containing silicone layers are hydrophobic and exhibit a high pure water contact angle, it is expected that the underlayer film will also be hydrophobic and exhibit a high pure water contact angle, thereby improving adhesion between the films and making them less likely to peel. Conversely, when the adhesion layer or silicone layer is hydrophilic and exhibits a low pure contact angle, it is expected that the underlayer film will also be hydrophilic and exhibit a low pure contact angle, thereby improving adhesion between the films and making them less likely to peel.

[0060] In addition, depending on the properties of the adhesive film, silicone layer, and underlayer film, He, H ２ , N ２ , air, etc. can be used.

[0061] The compound P according to the present invention exhibits a desired pure water contact angle not only when baked at a low temperature but also when baked at a high temperature, and also exhibits a desired pure water contact angle when mixed with a crosslinking agent, an acid catalyst, and a surfactant. This makes it possible to improve the adhesion with the upper layer film, and also makes it possible to improve the adhesion with He, H ２ , N ２ Furthermore, the compound P according to the present invention exhibits good planarization properties, and by modifying the molecular structure, the optical constants and etching rate can be adjusted to suit the process.

[0062] (Curable Composition) 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 an 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 an 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 an acid to increase the alkaline dissolution rate of the photoresist, a low molecular weight compound that decomposes in the presence of an 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 those disclosed in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0063] (Step of applying curable composition) This step is a step of applying a curable composition onto the resist underlayer film formed by the method for producing a resist underlayer film according to the present invention. Examples of methods that can be used to apply the curable composition include inkjet printing, dip coating, air knife coating, curtain coating, wire bar coating, gravure coating, extrusion coating, spin coating, and slit scanning. The inkjet printing method is suitable for applying the curable composition as droplets, and the spin coating method is suitable for coating the curable composition. In this step, an adhesion layer and / or a silicone layer containing 99% by mass or less or 50% by mass or less of Si can be formed on the resist underlayer film by coating or vapor deposition, and the curable composition can be applied thereon.

[0064] (Step of contacting the curable composition with a mold) In this step, the curable composition is brought into contact with a mold. For example, by bringing the liquid curable composition into contact with a mold having a master pattern for transferring a pattern shape, a liquid film is formed in which the curable composition fills the recesses of the fine pattern on the mold surface.

[0065] Considering the process of irradiating light or electron beams described later, it is recommended to use a mold whose substrate is made of a light-transmitting material. Specific examples of the mold substrate include glass, quartz, optically transparent resins such as PMMA and polycarbonate resins, transparent metal vapor deposition films, flexible films such as polydimethylsiloxane, photocured films, and metal films. Quartz is more preferable as the mold substrate because it has a small thermal expansion coefficient and small pattern distortion.

[0066] The fine pattern on the surface of the mold preferably has a pattern height of 4 nm or more and 200 nm or less. A certain level of pattern height is necessary to increase the processing accuracy of the substrate. A lower pattern height reduces the force required to peel the mold from the cured film in the process of separating the cured film and the mold, as described below, and also reduces the number of defects remaining on the mask side after the resist pattern is torn off. Taking these factors into consideration, it is recommended to select and adopt a pattern height with an appropriate balance. Furthermore, elastic deformation of the resist patterns due to the impact caused when peeling the mold can cause adjacent resist patterns to come into contact with each other, resulting in adhesion or damage to the resist patterns. This can sometimes be avoided by making the pattern height approximately twice or less the pattern width (aspect ratio of 2 or less).

[0067] In order to improve the releasability between the curable composition and the surface of the mold, the mold may be subjected to a surface treatment in advance. Examples of surface treatment methods include a method in which a release agent is applied to the surface of the mold to form a release agent layer. Examples of release agents include silicone-based release agents, fluorine-based release agents, hydrocarbon-based release agents, polyethylene-based release agents, polypropylene-based release agents, paraffin-based release agents, montan-based release agents, and carnauba-based release agents. Fluorine-based and hydrocarbon-based release agents are preferred. Commercially available products include, for example, Optool (registered trademark) DSX manufactured by Daikin Industries, Ltd. One type of release agent may be used alone, or two or more types may be used in combination.

[0068] In this step, the pressure applied to the curable composition when the mold and the curable composition are brought into contact with each other is not particularly limited. A pressure of 0 MPa or more and 100 MPa or less is recommended. The pressure is preferably 0 MPa or more and 50 MPa or less, 30 MPa or less, or 20 MPa or less.

[0069] If the pre-spreading of the droplets of the curable composition has progressed in the previous step (the step of applying the curable composition), the spreading of the curable composition in this step is completed quickly. As a result, the time for contacting the mold with the curable composition can be shortened. The contact time is not particularly limited, but is preferably 0.1 seconds or more and 600 seconds or less, 3 seconds or less, or 1 second or less. If the contact time is too short, spreading and filling may be insufficient, which may result in a defect called an unfilled defect.

[0070] This step can be carried out under any of the conditions of air atmosphere, reduced pressure atmosphere, and inert gas atmosphere, but is preferably carried out under a pressure of 0.0001 atmosphere or more and 10 atmospheres or less. In order to prevent the influence of oxygen and moisture on the curing reaction, it is recommended to carry out the step under a reduced pressure atmosphere or in an inert gas atmosphere. Specific examples of inert gases that can be used to create an inert gas atmosphere include nitrogen, carbon dioxide, helium, argon, CFC, HCFC, HFC, and mixed gases thereof.

[0071] This step may be performed in an atmosphere containing a condensable gas (hereinafter referred to as a "condensable gas atmosphere"). In this specification, the condensable gas refers to a gas that condenses and liquefies due to the capillary pressure generated when the gas is filled together with the curable composition into the recesses of the fine pattern formed on the mold and the gap between the mold and the substrate. The condensable gas exists as a gas in the atmosphere before the curable composition comes into contact with the mold in this step. When this step is performed in a condensable gas atmosphere, the gas filled into the recesses of the fine pattern is liquefied by the capillary pressure generated by the curable composition, thereby eliminating bubbles, resulting in excellent filling properties. The condensable gas may be dissolved in the curable composition.

[0072] The boiling point of the condensable gas is not limited as long as it is equal to or lower than the atmospheric temperature in this step, but is preferably −10° C. or higher, or +10° C. or higher and +23° C. or lower.

[0073] The vapor pressure of the condensable gas at the ambient temperature in this step is not particularly limited as long as it is equal to or lower than the mold pressure, and is preferably in the range of 0.1 MPa to 0.4 MPa.

[0074] Specific examples of condensable gases include chlorofluorocarbons (CFCs) such as trichlorofluoromethane, fluorocarbons (FCs), hydrochlorofluorocarbons (HCFCs), and 1,1,1,3,3-pentafluoropropane (CHF ２ CH ２ CF ３ , HFC-245fa, PFP), and other hydrofluorocarbons (HFCs), pentafluoroethyl methyl ether (CF ３ CF ２ OCH ３ and hydrofluoroethers (HFEs) such as HFE-245mc.

[0075] The condensable gas may be used alone or in combination of two or more. These condensable gases may also be used in combination with non-condensable gases such as air, nitrogen, carbon dioxide, helium, and argon. Air and helium are preferred as non-condensable gases to be mixed with the condensable gas.

[0076] (Step of irradiating the curable composition with light or an electron beam to form a cured film) In this step, the curable composition is irradiated with light or an electron beam to form a cured film. That is, the curable composition filled in the fine pattern of the mold is irradiated with light or an electron beam through the mold, and the curable composition filled in the fine pattern of the mold is cured in that state to form a cured film having the pattern shape.

[0077] The light or electron beam is selected depending on the wavelength to which the curable composition is sensitive. Specifically, ultraviolet light, X-rays, electron beams, etc. having a wavelength of 150 nm or more and 400 nm or less can be appropriately selected and used. Examples of light or electron beam light sources include high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, deep-UV lamps, carbon arc lamps, chemical lamps, metal halide lamps, xenon lamps, KrF excimer lasers, ArF excimer lasers, and F2 excimer lasers. The number of light sources may be one or more. Irradiation may be performed on the entire curable composition filled into the fine pattern of the mold, or on only a partial region. Light irradiation may be performed intermittently multiple times over the entire region on the substrate, or the entire region may be continuously irradiated. Alternatively, a partial region on the substrate may be irradiated a first time, and a different region from the partial region may be irradiated a second time.

[0078] The cured film thus obtained preferably has a pattern with a size of 1 nm or more, or 10 nm or more, and 10 mm or less, or 100 μm or less.

[0079] (Step of Separating the Cured Film from the Mold) In this step, the cured film is separated from the mold. By separating the patterned cured film from the mold, a free-standing cured film having a pattern that is a reverse pattern of the fine pattern formed on the mold is obtained.

[0080] The method for separating the patterned cured film from the mold is not particularly limited as long as it is a method for moving the cured film and the mold in directions that move them apart relatively, as long as a portion of the patterned cured film is not physically damaged, and various conditions are also not particularly limited. For example, the substrate may be fixed and the mold may be moved away from the substrate to separate them, or the mold may be fixed and the substrate may be moved away from the mold to separate them. Alternatively, the substrate and the mold may be pulled and moved in opposite directions to separate them.

[0081] If the above-described step of contacting the curable composition with the mold is carried out in a condensable gas atmosphere, when the cured film is separated from the mold in this step, the condensable gas evaporates as the pressure at the interface where the cured film and the mold contact each other decreases, thereby reducing the mold release force required to separate the cured film from the mold.

[0082] Through the above steps, a cured film can be prepared that has a desired concave-convex pattern shape derived from the concave-convex shape of the mold at desired positions.

[0083] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0084] Comparative Synthesis Example 1 Under nitrogen, 25.00 g of 2,2'-biphenol (manufactured by Tokyo Chemical Industry Co., Ltd.), 10.5 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 15.5 g of 1-pyrenecarboxaldehyde (manufactured by Aldrich), and 3.87 g of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a 100 mL two-neck flask. The mixture was then heated to 120°C and, after approximately 24 hours, allowed to cool to room temperature, precipitated with methanol, and the resulting precipitate was dried. The weight-average molecular weight Mw measured by GPC in terms of polystyrene was 5,000. The resulting polymer (A) was diluted with propylene glycol monomethyl ether acetate (PGMEA) to a solids concentration of 30%, and cation exchange resin and anion exchange resin in amounts equal to the solids were added, followed by stirring for 4 hours. The ion exchange resin was filtered to obtain a polymer solution.

[0085] Example 1 2.45 g of BPF tetramethylol (manufactured by Osaka Gas Chemicals Co., Ltd., (B)) was mixed with 0.98 g of a propylene glycol monomethyl ether acetate solution containing 1 mass % of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 21.38 g of propylene glycol monomethyl ether (PGME), and 0.19 g of propylene glycol monomethyl ether acetate. The mixture was then filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a resist underlayer film-forming composition.

[0086] Comparative Example 1 To 3.02 g of the resin solution (solid content 29.9% by mass) obtained in Comparative Synthesis Example 1, 0.10 g of propylene glycol monomethyl ether acetate containing 1% by mass of a surfactant (MEGAFAC R-40, manufactured by DIC Corporation), 3.68 g of propylene glycol monomethyl ether acetate, and 2.68 g of propylene glycol monomethyl ether were added and dissolved, and the resulting mixture was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a resist underlayer film-forming composition.

[0087] Comparative Example 2 2.70 g of BCF dimethylol compound (manufactured by Osaka Gas Chemicals Co., Ltd., (C)) was mixed with 1.06 g of a propylene glycol monomethyl ether acetate solution containing 5 mass % of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, a fluorine-based surfactant), 25.94 g of propylene glycol monomethyl ether, and 0.36 g of propylene glycol monomethyl ether acetate. The mixture was then filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a resist underlayer film-forming composition.

[0088] (Elution Test in Photoresist Solvent) The resist underlayer film-forming compositions prepared in Example 1 and Comparative Examples 1 and 2 were each applied to a silicon wafer using a spin coater. The resist underlayer film was baked on a hot plate at 400°C for 90 seconds to form a resist underlayer film (film thickness 170 nm). These resist underlayer films were immersed in a PGME / PGMEA mixed solvent (mass mixing ratio 70 / 30), which is a solvent used in photoresist solutions. When the resist underlayer film was insoluble in this solvent, it was marked with "○" and shown in Table 1.

[0089]

[0090] (Optical Constant Measurement) The resist underlayer film-forming compositions prepared in Example 1 and Comparative Examples 1 and 2 were each applied onto a silicon wafer using a spin coater. The resist underlayer film was baked on a hot plate at 400°C for 90 seconds to form a resist underlayer film (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. The results are shown in Table 2.

[0091]

[0092] Resist underlayer films (thickness: 100 nm) were formed on silicon wafers by the same method as above using the resist underlayer film-forming compositions prepared in Example 1 and Comparative Examples 1 and 2. The dry etching rates of these resist underlayer films were then evaluated using an RIE-10NR (manufactured by Samco Inc.) with CF as the etching gas. ４ Or O ２ / N ２ The dry etching rate of each resist underlayer film was calculated based on the dry etching rate of Comparative Example 1 set to 1.00. The results are shown in Table 3 as "relative dry etching rate."

[0093]

[0094] (Measurement of the amount of sublimated product of resist underlayer film) The amount of sublimated product was measured using the sublimated product amount measurement device described in WO 2007 / 111147. The resist underlayer film-forming compositions prepared in Example 1 and Comparative Examples 1 and 2 were each applied to a silicon wafer, and the amount of sublimated product was measured when the film thickness reached 50 nm after baking at 400°C for 90 seconds. The results are shown in Table 4. The values ​​shown in the table are (amount of sublimated product in Example 1 or Comparative Example 2) / (amount of sublimated product in Comparative Example 1). In addition, "-" in the table indicates that the amount of sublimated product was large and therefore no evaluation was performed.

[0095]

[0096] Using each of the compositions prepared above, the wafer edge removability and hump suppression properties were evaluated according to the following methods. The evaluation results are shown in Table 5 below. In the table, "-" indicates that the amount of sublimation was large and therefore no evaluation was performed.

[0097] (Formation of a substrate with a resist underlayer film after EBR treatment) The composition immediately after preparation was applied to a silicon wafer (substrate) by spin coating using a "CLEAN TRACK LITHIUS ProAP" spin coater (Tokyo Electron Limited). Then, while rotating at 1,000 rpm, a remover (propylene glycol monomethyl ether acetate / propylene glycol monoethyl ether = 30 / 70, mass ratio) was ejected to a position 3 mm from the outer edge of the substrate to the center of the substrate while moving the remover ejection nozzle at a speed of 1 mm per second. After ejecting the remover for 2 seconds at a position 3 mm from the outer edge of the substrate to the center of the substrate, the ejection of the remover was stopped, and the substrate was rotated at 2,000 rpm for 5 seconds. Next, the substrate was heated at 400 ° C. for 90 seconds to obtain a substrate with a resist underlayer film having an average film thickness of 170 nm.

[0098] (Wafer Edge Removability) Regarding wafer edge removability, the wafer outer periphery of the substrate with the resist underlayer film was observed using an optical microscope (magnification 10x), and if no uneven removal was observed, it was rated as "A" (good), and if uneven removal was observed, it was rated as "B" (bad).

[0099] (Hump Evaluation Method) Regarding hump suppression, the change in height from the outer peripheral edge of the substrate with the resist underlayer film to the center of the substrate was measured using a stylus surface roughness meter (Dektak XT-A). When the height of the substrate with the resist underlayer film was taken as 0, a height of less than 1 nm was evaluated as "A" (good), a height of 1 nm or more but less than 50 nm was evaluated as "B" (fairly good, poor), and a height of 50 nm or more was evaluated as "C" (poor). As can be seen from the results in Table 5, the compositions of the examples and the resist underlayer films formed from the compositions exhibited excellent hump suppression.

[0100]

[0101] According to the present invention, there is provided a novel resist underlayer film-forming composition that meets the requirements for reducing the amount of sublimation that contaminates equipment, and for improving etching resistance in substrate processing, particularly for suppressing hump formation, while also maintaining other favorable properties.

Claims

1. A resist underlayer film forming composition comprising a compound P containing a fluorene skeleton and having a partial structure including two groups selected from a phenolic hydroxyl group and a group in which a hydrogen atom of a hydroxyl group of a hydroxymethyl group and a hydroxymethyl group are each substituted with a substituent on one aromatic hydrocarbon ring, and a solvent.

2. The resist underlayer film-forming composition according to claim 1, wherein the compound P is a compound represented by the following formula (1). (In formula (1), Ar １ each independently represents a benzene ring, a naphthalene ring, or a biphenyl ring which may have a substituent, and Ar ２ each independently represents a benzene ring or a naphthalene ring, and R each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxyalkyl group having 2 to 6 carbon atoms.) 3. The resist underlayer film forming composition according to claim 1, wherein the content of the compound P is 90% by mass or more based on the total solid content in the composition.

4. The resist underlayer film forming composition according to claim 2, wherein in the formula (1), all Rs are hydrogen atoms.

5. The resist underlayer film forming composition according to claim 1, further comprising at least one of an acid and an acid generator.

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

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

8. A resist underlayer film which is a fired product of a coating film composed of the resist underlayer film forming composition according to any one of claims 1 to 7.

9. A method of manufacturing a semiconductor device, comprising: 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 7; a step of forming a resist film on the formed resist underlayer film; a step of forming a resist pattern by irradiating and developing the formed resist film with light or an electron beam; a step of etching the resist underlayer film through the formed resist pattern to form a patterned resist underlayer film; and a step of processing the semiconductor substrate through the patterned resist underlayer film.

10. A method of 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 claims 1 to 7; forming a hard mask on the formed resist underlayer film; forming a resist film on the formed hard mask; forming a resist pattern by irradiating and developing the formed resist film with light or an electron beam; etching the hard mask through the formed resist pattern to form a patterned hard mask; etching the resist underlayer film through the patterned hard mask to form a patterned resist underlayer film; and processing the semiconductor substrate through the patterned resist underlayer film.

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