Resist underlayer film forming composition having disulfide structure

Abstract

To provide a resist underlayer film having a particularly high dry etching rate, a composition for forming the resist underlayer film, a resist pattern forming method, and a semiconductor device manufacturing method.SOLUTION: The composition for forming the resist underlayer film contains: a bi- or higher functional compound having at least one disulfide bond and a tri- or higher functional compound, and / or a reaction product; and a solvent. The bi- or higher functional compound is a dicarboxylic acid containing a disulfide bond. The tri- or higher functional compound is a compound containing three or more epoxy groups.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resist underlayer film forming composition having a particularly high dry etching rate, a resist underlayer film using the resist underlayer film forming composition and a method for producing the same, a method for forming a resist pattern, and a method for producing a semiconductor device. [Background technology]

[0002] When a resist film is exposed to light, reflected waves can adversely affect the resist film. A resist underlayer film, also known as an anti-reflective film, is formed to suppress this. It is required that the resist underlayer film can be easily formed by applying a solution of a composition for forming a resist underlayer film and curing it. Therefore, the composition is required to contain a compound (polymer) that is easily cured by heating or the like and has high solubility in a predetermined solvent. The resist pattern formed on the resist underlayer film desirably has a rectangular cross-sectional shape in the direction perpendicular to the substrate (a straight bottom shape without so-called undercuts or bottom sagging). For example, if the resist pattern has an undercut or bottom sagging shape, problems occur such as the collapse of the resist pattern and the inability to process the workpiece (substrate, insulating film, etc.) into the desired shape or size during the lithography process. In addition, the resist underlayer film is required to have a higher dry etching rate than the upper resist film, that is, a higher selectivity ratio of the dry etching rate. Patent Document 1 discloses a resist underlayer film-forming composition that uses a polymer having a disulfide bond in the main chain. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Re-tabled publication No. 2009-096340 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacture of semiconductor devices, there is still a demand for a resist underlayer film having a high dry etching rate. In order to obtain a resist underlayer film having a high dry etching rate, it is known to use a composition containing a heteroatom as a polymer. The inventors of the present application have investigated various compounds and their reaction products (oligomers and polymers) in order to incorporate heteroatoms into the resist underlayer film at a higher concentration. As a result, they have found that the reaction product of a polyfunctional epoxy compound having three or more functionalities and a dicarboxylic acid is difficult to use as a resist underlayer film because the polymer becomes three-dimensional and becomes insoluble, but when a bifunctional or more compound having at least one disulfide bond, preferably a dicarboxylic acid, is used, the reaction product does not become insoluble in a solvent and can maintain high solubility. Furthermore, they have found that a higher etch rate can be achieved than with conventional techniques because disulfide groups can be introduced into the polyfunctional epoxy compound at multiple points. In view of solving such problems, the present invention has been made with an object of providing a resist underlayer film forming composition having a particularly high dry etching rate. Another object of the present invention is to provide a resist underlayer film using the resist underlayer film forming composition and a method for producing the same, a method for forming a resist pattern, and a method for producing a semiconductor device. [Means for solving the problem]

[0005] The present invention encompasses the following: [1] A resist underlayer film-forming composition comprising a difunctional or higher functional compound having at least one disulfide bond, a trifunctional or higher functional compound, and a solvent. [2] A composition for forming a resist underlayer film, comprising: a reaction product of a di- or higher functional compound having at least one disulfide bond and a tri- or higher functional compound; and a solvent. [3] The resist underlayer film forming composition according to [1] or [2], wherein the bifunctional or higher functional compound is a dicarboxylic acid containing a disulfide bond. [4] The resist underlayer film forming composition according to [1] or [2], wherein the tri- or higher functional compound is a compound containing three or more epoxy groups. [5] The dicarboxylic acid containing a disulfide bond is represented by the following formula (1):

[0006] [ka] (In formula (1), X 1 and X 2 represents an alkylene group having 1 to 10 carbon atoms, each of which may be substituted, an arylene group having 6 to 40 carbon atoms, or a combination thereof. The resist underlayer film forming composition according to [3], [6] In the formula (1), X 1 and X 2 and each of the groups is an alkylene group having 1 to 3 carbon atoms. [7] The resist underlayer film forming composition according to any one of [1], [2], or [4], wherein the tri- or higher functional compound contains a heterocyclic structure. [8] The resist underlayer film forming composition according to [7], wherein the heterocyclic structure includes a triazine structure. [9] The resist underlayer film forming composition according to any one of [1] to [8], further comprising a crosslinking catalyst.

[10] The resist underlayer film forming composition according to any one of [1] to [9], further comprising a crosslinking agent.

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

[10] , further comprising a surfactant.

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

[11] .

[13] A method for forming a resist pattern used in manufacturing a semiconductor device, comprising the steps of: applying the resist underlayer film forming composition according to any one of [1] to

[11] onto a semiconductor substrate and baking the composition to form a resist underlayer film; applying a resist onto the resist underlayer film and baking the composition to form a resist film; exposing the resist underlayer film and the semiconductor substrate coated with the resist to light; and developing the resist film after exposure.

[14] A process for forming a resist underlayer film on a semiconductor substrate, the resist underlayer film being composed of the resist underlayer film forming composition according to any one of [1] to

[11] ; forming a resist film on the resist underlayer film; forming a resist pattern by irradiating the resist film with light or an electron beam and then developing it; forming a patterned resist underlayer film by etching the resist underlayer film through the formed resist pattern; processing a semiconductor substrate using the patterned resist underlayer film; A method for manufacturing a semiconductor device, comprising:

[15] A method for producing a reaction product having at least one disulfide bond, comprising a step of reacting a bifunctional or higher compound having at least one disulfide bond with a trifunctional or higher compound.

[16] A method for producing a resist underlayer film-forming composition, comprising a step of reacting a di- or higher functional compound having at least one disulfide bond with a tri- or higher functional compound.

[17] A method for producing a patterned substrate, comprising the steps of: applying the resist underlayer film forming composition according to any one of [1] to

[11] onto a semiconductor substrate and baking the composition to form a resist underlayer film; applying a resist onto the resist underlayer film and baking the composition to form a resist film; exposing the resist underlayer film and the semiconductor substrate coated with the resist; and developing and patterning the resist film after exposure. Effect of the Invention

[0007] The resist underlayer film forming composition of the present invention has a high dry etching rate, and can solve various problems caused by thinning of the resist film thickness, thereby achieving finer processing of finer semiconductor substrates. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Resist underlayer film-forming composition, method for producing a reaction product having at least one disulfide bond, and method for producing a resist underlayer film-forming composition> The resist underlayer film forming composition of the present application is a resist underlayer film forming composition containing a di- or higher functional compound having at least one disulfide bond, a tri- or higher functional compound, and a solvent. The term "functional" refers to a concept that focuses on the chemical attributes and chemical reactivity of a substance. Although functional groups are assumed to have their own physical properties and chemical reactivity, in this application, it refers to reactive substituents that can bond with other compounds. That is, for example, trifunctional means that the compound has three reactive substituents. Specific examples of reactive substituents include hydroxyl, epoxy, acyl, acetyl, formyl, benzoyl, carboxyl, carbonyl, amino, imino, cyano, azo, azido, thiol, sulfo, and allyl groups. Among these, epoxy or carboxy groups are preferred, and epoxy groups are most preferred. The functional groups contained in the above compounds may be the same or different, but are preferably the same. Incidentally, "having at least one disulfide bond" means "having at least one disulfide bond" in one molecule. The bifunctional or higher functional compound having at least one disulfide bond and the trifunctional or higher functional compound are each one or two or more kinds, but it is preferable that the number of kinds is three or less, it is preferable that the number of kinds is two or less, and it is most preferable that the number of kinds is one. The molar ratio of the tri- or higher functional compound to the bi- or higher functional compound having at least one disulfide bond is, for example, 1:0.1 to 10, preferably 1:1 to 5, and more preferably 1:3. The compound preferably has a molecular weight of at least 100. The upper limit of the molecular weight of the compound is, for example, 999.

[0009] The resist underlayer film forming composition of the present application may contain a reaction product (oligomer and / or polymer) between a di- or higher functional compound having at least one disulfide bond and a tri- or higher functional compound. The molar ratio of the bifunctional or higher compound having at least one sulfide bond to the trifunctional or higher compound is, for example, 1:0.1-10, preferably 1:1-5, and more preferably 1:3. The reaction product of the present application may be an oligomer, and preferably has a molecular weight of 300 or more. The upper limit of the molecular weight is, for example, 999. The reaction product (oligomer and / or polymer) can be produced by a method known per se, as well as by the method described in Japanese Patent No. 5041175. As the polymer, a polymer having a weight average molecular weight of, for example, 1,000 to 100,000, or 1,100 to 50,000, or 1,200 to 30,000, or 1,300 to 20,000 can be used.

[0010] The resist underlayer film forming composition of the present application may contain the above-mentioned compound and / or the above-mentioned reaction product.

[0011] The resist underlayer film forming composition of the present application may be a bifunctional or higher compound having at least one disulfide bond, but is preferably a bifunctional compound having at least one disulfide bond. A dicarboxylic acid containing a disulfide bond is more preferred. A dicarboxylic acid in which a disulfide bond interrupts an alkylene group having 2 or more carbon atoms. A dicarboxylic acid in which a disulfide bond interrupts an alkylene group having 2 to 10 carbon atoms is more preferred. The dicarboxylic acid containing a disulfide bond is represented by the following formula (1):

[0012] [ka] (In formula (1), X 1 and X 2 each represents an optionally substituted alkylene group having 1 to 10 carbon atoms, each represents an optionally substituted arylene group having 6 to 40 carbon atoms, or a combination thereof.

[0013] X 1 and X 2 may be the same or different. Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, a cyclopropylene group, an n-butylene group, an isobutylene group, an s-butylene group, a t-butylene group, a cyclobutylene group, a 1-methyl-cyclopropylene group, a 2-methyl-cyclopropylene group, an n-pentylene group, a 1-methyl-n-butylene group, a 2-methyl-n-butylene group, a 3-methyl-n-butylene group, a 1,1-dimethyl-n-propylene group, a 1,2-dimethyl-n-propylene group, a 2,2-dimethyl-n-propylene group, a 1-ethyl-n- Propylene, cyclopentylene, 1-methyl-cyclobutylene, 2-methyl-cyclobutylene, 3-methyl-cyclobutylene, 1,2-dimethyl-cyclopropylene, 2,3-dimethyl-cyclopropylene, 1-ethyl-cyclopropylene, 2-ethyl-cyclopropylene, n-hexylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-pentylene, 4-methyl-n-pentylene, 1,1-dimethyl-n-butylene, 1,2-dimethyl-n-butylene, 1,3-dimethyl-n-butylene group, 2,2-dimethyl-n-butylene group, 2,3-dimethyl-n-butylene group, 3,3-dimethyl-n-butylene group, 1-ethyl-n-butylene group, 2-ethyl-n-butylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2-trimethyl-n-propylene group, 1-ethyl-1-methyl-n-propylene group, 1-ethyl-2-methyl-n-propylene group, cyclohexylene group, 1-methyl-cyclopentylene group, 2-methyl-cyclopentylene group, 3-methyl-cyclopentylene group, 1-ethyl-cyclobutylene group, 2-ethyl-cyclobutylene group cyclobutylene, 3-ethyl-cyclobutylene, 1,2-dimethyl-cyclobutylene, 1,3-dimethyl-cyclobutylene, 2,2-dimethyl-cyclobutylene, 2,3-dimethyl-cyclobutylene, 2,4-dimethyl-cyclobutylene, 3,3-dimethyl-cyclobutylene, 1-n-propyl-cyclopropylene, 2-n-propyl-cyclopropylene, 1-isopropyl-cyclopropylene, 2-isopropyl-cyclopropylene, 1,2,2-trimethyl-cyclopropylene, 1,2,3-trimethyl-cyclopropylene, 2,2,Examples of the cyclopropylene group include a 3-trimethyl-cyclopropylene group, a 1-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-1-methyl-cyclopropylene group, a 2-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-3-methyl-cyclopropylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, and an n-decanylene group.

[0014] Examples of the arylene group having 6 to 40 carbon atoms include a phenylene group, an o-methylphenylene group, an m-methylphenylene group, a p-methylphenylene group, an α-naphthylene group, a β-naphthylene group, an o-biphenylylene group, an m-biphenylylene group, a p-biphenylylene group, a 1-anthrylene group, a 2-anthrylene group, a 9-anthrylene group, a 1-phenanthrylene group, a 2-phenanthrylene group, a 3-phenanthrylene group, a 4-phenanthrylene group, and a 9-phenanthrylene group.

[0015] Examples of the substituents on the alkylene group and arylene group include, but are not limited to, halogen atoms (fluorine, chlorine, bromine, iodine), a nitro group, a cyano group, an amino group, a hydroxy group, a carbonyl group, a carbonyloxy group, a methoxy group, and an ethoxy group.

[0016] In the formula (1), X 1 and X 2 are the same or different and each independently represent an alkylene group having 1 to 3 carbon atoms. The alkylene group having 1 to 3 carbon atoms is preferably a methylene group, an ethylene group, an ethylidene group, a trimethylene group, a propylene group, a propylidene group or an isopropylene group, and particularly preferably a methylene group or an ethylene group. Above X 1 and X 2 may be a combination of one or more of the above-mentioned optionally substituted alkylene groups having 1 to 10 carbon atoms and one or more of the above-mentioned optionally substituted arylene groups having 6 to 40 carbon atoms. Preferred is a combination of the one of the above-mentioned optionally substituted alkylene groups having 1 to 10 carbon atoms and the one of the above-mentioned optionally substituted arylene groups having 6 to 40 carbon atoms. Particularly preferred compounds as the dicarboxylic acid (B) having a disulfide bond represented by the formula (1) used in the present invention include, for example, the following formulae (B-1) to (B-4).

[0017] [ka] The dicarboxylic acid (B) having a disulfide bond is preferably dithiodiglycolic acid of the formula (B-1) or 3,3'-dithiodipropionic acid of the formula (B-3). The resist underlayer film forming composition of the present application may contain a trifunctional or higher functional compound, and preferably contains a trifunctional compound. Incidentally, "containing three or more epoxy groups" means "containing three or more epoxy groups" in one molecule. The tri- or higher functional compound is preferably a compound containing three or more epoxy groups. The tri- or higher functional compound is preferably a compound containing 3 to 10 epoxy groups, more preferably a compound containing 3 to 8 epoxy groups, more preferably a compound containing 3 to 6 epoxy groups, more preferably a compound containing 3 or 4 epoxy groups, and most preferably a compound containing 3 epoxy groups. Examples of the compound (A) containing three or more epoxy groups include a glycidyl ether compound, a glycidyl ester compound, a glycidyl amine compound, and a glycidyl group-containing isocyanurate. Examples of the epoxy compound (A) used in the present invention include the following formulae (A-1) to (A-15).

[0018] [ka] Compound (A-1) is available from Nissan Chemical Industries, Ltd. under the trade names TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, and TEPIC-L (all of which are 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid). The compound represented by formula (A-2) is available from Nissan Chemical Industries, Ltd. under the trade name TEPIC-VL. The compound represented by formula (A-3) is available from Nissan Chemical Industries, Ltd. under the trade name TEPIC-FL. The compound represented by formula (A-4) is available from Nissan Chemical Industries, Ltd. under the trade name TEPIC-UC. The compound represented by formula (A-5) is available from Nagase Chemtec Corporation under the trade name Denacol EX-411. The compound represented by formula (A-6) is available from Nagase Chemtec Corporation under the trade name Denacol EX-521. The compound represented by formula (A-7) is available from Mitsubishi Gas Chemical Company, Inc. under the trade name TETRAD-X. The compound represented by formula (A-8) is available from Showa Denko KK under the trade name BATG. The compound represented by formula (A-9) is available from Nippon Steel & Sumikin Chemical Co., Ltd. under the trade name YH-434L. The compound represented by formula (A-10) is available from Asahi Yukizai Kogyo Co., Ltd. under the trade name TEP-G. The compound represented by formula (A-11) is available from DIC Corporation under the trade name EPICLON HP-4700. Formula (A-12) is available under the trade name Epolead GT401 from Daicel Corp. In addition, a, b, c, and d are each 0 or 1, and a+b+c+d=1. Equation (A-13) can be obtained as: Equation (A-14) can be obtained as: Equation (A-15) can be obtained as:

[0019] The tri- or higher functional compound preferably contains a heterocyclic structure. Examples of the heterocycle include furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, pyrrolidine, piperidine, piperazine, morpholine, indole, purine, quinoline, isoquinoline, quinuclidine, chromene, thianthrene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, carbazole, triazinone, triazinedione, and triazinetrione. The heterocyclic structure is preferably a triazineone, triazinedione or triazinetrione structure, and most preferably a triazinetrione structure. Particularly preferred compounds (A) containing three or more epoxy groups are 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid of formula (A-1) or triglycidyl acetate isocyanuric acid of formula (A-13). The bifunctional compound having at least one disulfide bond and the trifunctional compound of the present application may specifically be reaction products having structures of the following formulae (P-1) to (P-5).

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] [ka] Furthermore, the resist underlayer film forming composition of the present invention may further contain one or more compounds different from the bifunctional or higher compound and the trifunctional or higher compound having at least one disulfide bond. Examples of the compound include compounds containing an acidic group and a hydroxyl group. A specific example is glycolic acid.

[0025] [solvent] The resist underlayer film forming composition of the present invention can be produced by dissolving the above-mentioned components in an organic solvent, and is used in the state of a homogeneous solution. As the solvent for the resist underlayer film-forming composition according to the present invention, any solvent that can dissolve the above-mentioned compound or its reaction product can be used without any particular limitation. In particular, since the resist underlayer film-forming composition according to the present invention is used in a homogeneous solution state, in consideration of its coating performance, it is recommended to use a solvent that is generally used in lithography processes in combination. Examples of the organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Examples of the solvent include cyclopentane, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. 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, etc. are preferred, with propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate being particularly preferred.

[0026] [Crosslinking catalyst] The resist underlayer film forming composition of the present invention may contain a crosslinking catalyst as an optional component in order to promote the crosslinking reaction. As the crosslinking catalyst, in addition to an acidic compound or a basic compound, a compound that generates an acid or a base by heat may be used. As the acidic compound, a sulfonic acid compound or a carboxylic acid compound may be used, and as the compound that generates an acid by heat, a thermal acid generator may be used. Examples of sulfonic acid compounds or carboxylic acid compounds include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium trifluoromethanesulfonate, pyridinium-p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, pyridinium-4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, 4-nitrobenzenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid. Examples of thermal acid generators include K-PURE (registered trademark) CXC-1612, CXC-1614, TAG-2172, TAG-2179, TAG-2678, and TAG2689 (all manufactured by King Industries), and SI-45, SI-60, SI-80, SI-100, SI-110, and SI-150 (all manufactured by Sanshin Chemical Industry Co., Ltd.). These crosslinking catalysts can be used alone or in combination of two or more. As the basic compound, an amine compound or an ammonium hydroxide compound can be used, and as the compound that generates a base by heat, urea can be used.

[0027] Examples of the amine compound include tertiary amines such as triethanolamine, tributanolamine, trimethylamine, triethylamine, tri-normal propylamine, triisopropylamine, tri-normal butylamine, tri-tert-butylamine, tri-normal octylamine, triisopropanolamine, phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, and aromatic amines such as pyridine and 4-dimethylaminopyridine.Other examples of the amine compound include primary amines such as benzylamine and normal butylamine, and secondary amines such as diethylamine and di-normal butylamine.These amine compounds can be used alone or in combination of two or more. Examples of ammonium hydroxide compounds include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, cetyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, and phenyltriethylammonium hydroxide. As a compound that generates a base by heat, for example, a compound that has a thermolabile group such as an amide group, a urethane group, or an aziridine group and generates an amine by heating can be used. Other examples of the compound that generates a base by heat include urea, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylphenylammonium chloride, benzyldodecyldimethylammonium chloride, benzyltributylammonium chloride, and choline chloride. When the resist underlayer film forming composition contains a crosslinking catalyst, the content thereof is 0.0001 to 20% by weight, preferably 0.01 to 15% by weight, and more preferably 0.1 to 10% by mass, based on the total solid content of the resist underlayer film forming composition. Among the above, acidic compounds and / or compounds that generate an acid by heat (crosslinking acid catalysts) are preferred.

[0028] [Crosslinking agent] The resist underlayer film forming composition of the present invention may contain a crosslinking agent component. Examples of the crosslinking agent include melamine-based, substituted urea-based, and polymers thereof. A crosslinking agent having at least two crosslinking-forming substituents is preferred, and is a compound such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or methoxymethylated thiourea. Condensates of these compounds may also be used. In addition, a crosslinking agent having high heat resistance can be used as the crosslinking agent. A compound having a crosslinking substituent with an aromatic ring (e.g., a benzene ring, a naphthalene ring) in the molecule can be used as the crosslinking agent having high heat resistance. This compound can be a compound having a partial structure of the following formula (5-1) or a polymer or oligomer having a repeating unit of the following formula (5-2).

[0029] [ka] Above R 11 , R 12 , R 13 , and R 14is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 1-ethyl-n-propyl group, Cyclopentyl, 1-methylcyclobutyl, 2-methylcyclobutyl, 3-methylcyclobutyl, 1,2-dimethylcyclopropyl, 2,3-dimethylcyclopropyl, 1-ethylcyclopropyl, 2-ethylcyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2- Dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3 -ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2,4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,Examples of the cyclopropyl group include a 3-trimethylcyclopropyl group, a 1-ethyl-2-methylcyclopropyl group, a 2-ethyl-1-methylcyclopropyl group, a 2-ethyl-2-methylcyclopropyl group, and a 2-ethyl-3-methylcyclopropyl group. m1 is 1≦m1≦6-m2, m2 is 1≦m2≦5, m3 is 1≦m3≦4-m2, and m4 is 1≦m4≦3. Examples of the compounds, polymers and oligomers of the formula (5-1) and the formula (5-2) are shown below.

[0030] [ka]

[0031] [ka] 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 (6-22) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TMOM-BP. The amount of the 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% by weight, preferably 0.01 to 50% by weight, and more preferably 0.1 to 40% by weight, based on the total solid content of the resist underlayer film-forming composition. These crosslinking agents may cause a crosslinking reaction by self-condensation, but when crosslinkable substituents are present in the above polymer of the present invention, they can cause a crosslinking reaction with the crosslinkable substituents.

[0032] [Surfactants] The resist underlayer film forming composition of the present invention may contain a surfactant as an optional component in order to improve the coating property on a semiconductor substrate. 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, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monostearate. nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan trioleate and polyoxyethylene sorbitan tristearate; fluorosurfactants such as F-TOP (registered trademark) EF301, EF303, and EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Megafac (registered trademark) F171, F173, R-30, R-30N, R-40, and R-40-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.). These surfactants can be used alone or in combination of two or more. When the resist underlayer film forming composition contains a surfactant, the content of the surfactant is 0.0001 to 10% by weight, preferably 0.01 to 5% by weight, based on the total solid content of the resist underlayer film forming composition. The solid content of the resist underlayer film forming composition according to the present invention is usually 0.1 to 70 mass%, preferably 0.1 to 60 mass%. The solid content is the content of all components excluding the solvent from the resist underlayer film forming composition. The ratio of the compound or reaction product of the present application in the solid content is preferably 1 to 100 mass%, 1 to 99.9 mass%, 50 to 99.9 mass%, 50 to 95 mass%, and 50 to 90 mass%, in that order.

[0033] [Other ingredients] The resist underlayer film forming composition of the present invention may contain a light absorbing agent, a rheology control agent, an adhesion promoter, etc. The rheology control agent is effective in improving the fluidity of the resist underlayer film forming composition. The adhesion promoter is effective in improving the adhesion between the semiconductor substrate or resist and the underlayer film. 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 Synthesis 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; CI Fluorescent Brightening Agent. Suitable examples of the light absorbing agent that can be used include 112, 135, and 163; CI Solvent Orange 2 and 45; CI Solvent Red 1, 3, 8, 23, 24, 25, 27, and 49; CI Pigment Green 10; and CI 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.

[0034] The rheology control agent is mainly added to improve the flowability of the resist underlayer film forming composition, and to improve the film thickness uniformity of the resist underlayer film and the filling ability of the resist underlayer film forming composition into the hole, especially in the baking process.Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate, adipic acid derivatives such as di-normal butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyl decyl adipate, maleic acid derivatives such as di-normal 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 normal butyl stearate and glyceryl stearate.These rheology control agents are usually blended at a ratio of less than 30% by mass based on the total solid content of the resist underlayer film forming composition. 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 in particular for the purpose of preventing 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 the adhesive auxiliary 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 ureas such as 1,1-dimethylurea and 1,3-dimethylurea, or thiourea compounds. These adhesive auxiliary agents are usually blended in an amount of less than 5% by mass, preferably less than 2% by mass, based on the total solid content of the resist underlayer film-forming composition.

[0035] [Method for producing resist underlayer film, resist pattern, semiconductor device, and patterned substrate] Hereinafter, a resist underlayer film produced using the resist underlayer film forming composition according to the present invention, a method for forming a resist pattern, and a method for producing a semiconductor device will be described. The resist pattern according to the present invention can be produced by applying the above-mentioned resist underlayer film forming composition onto a semiconductor substrate and baking it. Examples of semiconductor substrates to which the resist underlayer film forming composition of the present invention can be applied include silicon wafers, germanium wafers, and wafers of compound semiconductors such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride. When using a semiconductor substrate having an inorganic film formed on its surface, the inorganic film is formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum deposition, or spin-coating (spin-on glass: SOG). Examples of the inorganic film include polysilicon film, silicon oxide film, silicon nitride film, BPSG (Boro-Phospho Silicate Glass) film, titanium nitride film, titanium nitride oxide film, tungsten film, gallium nitride film, and gallium arsenide film. The resist underlayer film forming composition of the present invention is applied onto such a semiconductor substrate by a suitable application method such as a spinner or coater. Then, the composition is baked using a heating means such as a hot plate to form a resist underlayer film. The baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 minutes to 60 minutes. The baking temperature is preferably 120°C to 350°C, the baking time is 0.5 minutes to 30 minutes, and more preferably, the baking temperature is 150°C to 300°C, and the baking time is 0.8 minutes to 10 minutes. The thickness of the resist underlayer film formed is, for example, 0.001 μm (1 nm) to 10 μm, preferably 0.002 μm (2 nm) to 1 μm, more preferably 0.005 μm (5 nm) to 0.5 μm (500 nm). If the baking temperature is lower than the above range, crosslinking may be insufficient, and the formed protective film may not be resistant to a resist solvent or a basic hydrogen peroxide aqueous solution. On the other hand, if the baking temperature is higher than the above range, the resist underlayer film may be decomposed by heat.

[0036] The photoresist formed by coating and baking on the resist underlayer film by a method known per se is not particularly limited as long as it is sensitive to the light used for exposure. Either negative photoresist or positive photoresist can be used. There are positive photoresists made of novolac resin and 1,2-naphthoquinone diazide sulfonic acid ester, chemically amplified photoresists made of a binder having a group that decomposes with acid to increase the alkaline dissolution rate and a photoacid generator, chemically amplified photoresists made of a low molecular compound that decomposes with acid to increase the alkaline dissolution rate of the photoresist, an alkali-soluble binder, and a photoacid generator, and chemically amplified photoresists made of a binder having a group that decomposes with acid to increase the alkaline dissolution rate, a low molecular compound that decomposes with acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator. Examples of such photoresists include V146G (trade name) manufactured by JSR Corporation, APEX-E (trade name) manufactured by Shipley & Sons, PAR710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and AR2772 and SEPR430 (trade names) manufactured by Shin-Etsu Chemical Co., Ltd. Further examples of such photoresists include fluorine atom-containing polymer photoresists as described in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0037] Exposure is performed through a mask (reticle) for forming a predetermined pattern, and for example, i-rays, KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet) or EB (electron beam) is used. An alkaline developer is used for development, and the development temperature is appropriately selected from 5°C to 50°C and the development time is appropriately selected from 10 seconds to 300 seconds. As the alkaline developer, for example, aqueous solutions of alkalis such as inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia water, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, cyclic amines such as pyrrole and piperidine, etc. can be used. Furthermore, an appropriate amount of alcohols such as isopropyl alcohol and surfactants such as nonionic surfactants can be added to the aqueous solutions of the above alkalis. Among these, the preferred developer is a quaternary ammonium salt, more preferably tetramethylammonium hydroxide and choline. Furthermore, a surfactant or the like can be added to these developers. Instead of the alkaline developer, a method can be used in which development is performed with an organic solvent such as butyl acetate to develop the part of the photoresist where the alkaline dissolution rate is not improved. Next, the resist underlayer film is dry-etched using the formed resist pattern as a mask, whereby if the inorganic film is formed on the surface of the semiconductor substrate used, the surface of the inorganic film is exposed, and if the inorganic film is not formed on the surface of the semiconductor substrate used, the surface of the semiconductor substrate is exposed. EXAMPLES

[0038] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these. The apparatuses used for measuring the weight average molecular weight of the polymers obtained in the following synthesis examples are shown below. Equipment: Tosoh Corporation HLC-8320GPC GPC column: Shodex (registered trademark) Asahipak (registered trademark) (Showa Denko K.K.) Column temperature: 40℃ Flow rate: 0.6mL / min Eluent: N,N-dimethylformamide (DMF) Standard sample: Polystyrene (Tosoh Corporation)

[0039] <Example 1> A reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Industries, Ltd.), 7.42 g of dithiodiglycolic acid, 0.38 g of ethyltriphenylphosphonium bromide, and 47.19 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 20 hours under a nitrogen atmosphere to obtain a transparent solution of the reaction product. A reaction product corresponding to formula (C-1) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 880. In addition, in formula (C-1), a:b=100:300 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 6.65 g of a solution of the reaction product corresponding to the above formula (C-1) (solid content: 17.5 wt%), 0.03 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 11.43 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0040] [ka]

[0041] <Example 2> A transparent solution of the reaction product was obtained by heating and stirring in a reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Co., Ltd.), 8.56 g of 3,3'-dithiodipropionic acid, 0.38 g of ethyltriphenylphosphonium bromide, and 51.76 g of propylene glycol monomethyl ether under a nitrogen atmosphere at 100°C for 21 hours. A reaction product corresponding to formula (C-2) was obtained as a solution, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 5700. In addition, in formula (C-2), a:b=100:300 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 7.09 g of a solution of the reaction product corresponding to the formula (C-2) (solid content: 16.4 wt%), 0.03 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 11.00 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0042] [ka]

[0043] <Example 3> A transparent solution of the reaction product was obtained by heating and stirring in a reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Co., Ltd.), 4.40 g of 3,3'-dithiodipropionic acid, 1.59 g of glycolic acid, 0.39 g of ethyltriphenylphosphonium bromide, and 41.51 g of propylene glycol monomethyl ether under a nitrogen atmosphere at 100°C for 15 hours. A reaction product corresponding to formula (C-3) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 1400. In addition, in formula (C-3), a:b:c=100:150:150 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 6.41 g of a solution of the reaction product corresponding to the formula (C-3) (solid content: 18.2 wt%), 0.03 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 11.67 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0044] [ka]

[0045] <Synthesis Example 1> 38.70 g of tricarboxymethylisocyanuric acid (TAICA) synthesized according to the method described in U.S. Pat. No. 3,230,220, 300.00 g of N-methyl-2-pyrrolidone (Kanto Chemical Co., Ltd.), 70.91 g of allyl bromide (Tokyo Chemical Industry Co., Ltd.), and 79.38 g of potassium carbonate (Kanto Chemical Co., Ltd.) were charged and heated to 80-90°C. Then, the reaction was carried out for 2 hours and it was confirmed that the reaction reached a constant weight. After the reaction was completed, 580.50 g of toluene (Kanto Chemical Co., Ltd.) was added. Filtration was carried out and the mixture was washed three times with 580.50 g of water. The organic layer was concentrated and dried, and then 387.00 g of ethanol (Kanto Chemical Co., Ltd.) was charged and stirred at 20-30°C for 30 minutes. After the stirring was completed, the mixture was filtered and the obtained crystals were dried to obtain 44.32 g of the desired product represented by the formula (M-1) (triallyl acetate isocyanuric acid: TAAICA) in a yield of 85%.

[0046] [ka]

[0047] <Synthesis Example 2> 44.32 g of TAAICA synthesized in Synthesis Example 1 and 443.20 g of chloroform (manufactured by Kanto Chemical Co., Ltd.) were charged, and 125.06 g of m-chloroperbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto. The reaction was carried out for 47 hours. After the reaction was completed, 88.64 g of chloroform (manufactured by Kanto Chemical Co., Ltd.) was added. Furthermore, it was washed with 886.40 g of 5% sodium hydrogen carbonate (manufactured by Kanto Chemical Co., Ltd.). It was subsequently washed with 443.20 g of 10% sodium sulfite (manufactured by Kanto Chemical Co., Ltd.), 886.40 g of 5% sodium hydrogen carbonate (manufactured by Kanto Chemical Co., Ltd.), and further washed twice with 443.20 g of water. After concentration, column purification was carried out. After column purification, 41.31 g of the target product triglycidyl acetate isocyanuric acid (TAGICA) represented by formula (A-13) was obtained in a yield of 84%.

[0048] [ka]

[0049] <Example 4> 9.00g of TAGICA obtained in Synthesis Example 2, 6.99g of dithiodiglycolic acid, 0.53g of ethyltriphenylphosphonium bromide, and 66.11g of propylene glycol monomethyl ether were added to a reaction flask, and the mixture was heated and stirred at 70°C for 23 hours under a nitrogen atmosphere to obtain a transparent reaction product corresponding to formula (C-4), whose weight average molecular weight Mw measured in terms of polystyrene by GPC was 3000. In addition, in formula (C-4), a:b=100:200 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 8.31 g of a solution of the reaction product corresponding to the formula (C-4) (solid content: 11.56 wt%), 0.04 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 9.75 g of propylene glycol monomethyl ether, and 1.90 g of propylene glycol monomethyl ether acetate.

[0050] [ka]

[0051] <Comparative Example 1> A reaction flask containing 6.00 g of monoallyl diglycidyl isocyanuric acid (product name: MADGIC, manufactured by Shikoku Chemical Industry Co., Ltd.), 4.70 g of 3,3'-dithiodipropionic acid, 0.40 g of ethyl triphenylphosphonium bromide, and 44.39 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere to obtain a transparent solution of the reaction product. A reaction product corresponding to formula (D-1) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 3900. In addition, in formula (D-1), a:b=100:105 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 6.78 g of a solution of the reaction product corresponding to the formula (D-1) (solid content: 17.0 wt%), 0.05 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 11.30 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0052] [ka]

[0053] <Comparative Example 2> A reaction flask containing 15.00 g of diglycidyl dimethylhydantoin (product name: DG-DMH, Shikoku Chemical Industry Co., Ltd., 30 wt% propylene glycol monomethyl ether solution), 4.32 g of 3,3'-dithiodipropionic acid, 0.36 g of ethyltriphenylphosphonium bromide, and 10.84 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere to obtain a transparent solution of the reaction product. A reaction product corresponding to formula (D-2) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 3500. In addition, in formula (D-2), a:b=100:105 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 9.29 g of a solution of the reaction product corresponding to the formula (D-2) (solid content: 12.4 wt%), 0.04 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 8.79 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0054] [ka]

[0055] <Comparative Example 3> A reaction flask containing 6.00 g of diglycidyl terephthalate (product name: Denacol EX-711, Nagase ChemteX Corporation), 4.56 g of 3,3'-dithiodipropionic acid, 0.38 g of ethyltriphenylphosphonium bromide, and 43.77 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 24 hours under a nitrogen atmosphere to obtain a transparent solution of the reaction product. A reaction product corresponding to formula (D-3) was obtained, and the weight average molecular weight Mw measured in terms of polystyrene by GPC was 4500. In addition, in formula (D-3), a:b=100:105 (molar ratio). A solution of a resist underlayer film-forming composition for lithography was prepared by adding 7.82 g of a solution of the reaction product corresponding to the formula (D-3) (solid content: 14.8% by mass), 0.04 g of pyridinium trifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-40, fluorine-based surfactant), 10.25 g of propylene glycol monomethyl ether, and 1.88 g of propylene glycol monomethyl ether acetate.

[0056] [ka]

[0057] <Comparative Example 4> A reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Co., Ltd.), 6.11 g of 2,2'-thiodiglycolic acid, 0.38 g of ethyltriphenylphosphonium bromide, and 41.97 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 21 hours under a nitrogen atmosphere in an attempt to prepare a resin solution corresponding to formula (D-4), but a part of the reaction product precipitated as an insoluble matter. In formula (D-4), a:b=100:300 (molar ratio).

[0058] [ka]

[0059] <Comparative Example 5> A reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Co., Ltd.), 7.99 g of methylene bis(thioglycolic acid), 0.38 g of ethyltriphenylphosphonium bromide, and 49.47 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 21 hours under a nitrogen atmosphere in an attempt to prepare a resin solution corresponding to formula (D-5), but a part of the reaction product precipitated as an insoluble matter. In formula (D-5), a:b=100:300 (molar ratio).

[0060] [ka]

[0061] <Comparative Example 6> A reaction flask containing 4.00 g of 1,3,5-tris(2,3-epoxypropyl)isocyanuric acid (product name: TEPIC-SS, manufactured by Nissan Chemical Co., Ltd.), 8.56 g of (ethylenedithio)diacetic acid, 0.38 g of ethyltriphenylphosphonium bromide, and 51.76 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 21 hours under a nitrogen atmosphere in an attempt to prepare a resin solution corresponding to formula (D-6), but a part of the reaction product precipitated as an insoluble matter. In formula (D-6), a:b=100:300 (molar ratio).

[0062] [ka]

[0063] [Evaluation of solubility of reaction products] The state of the reaction solutions containing the reaction products obtained in Examples 1 to 4 and Comparative Examples 1 to 6 is shown in Table 1.

[0064] [Table 1] From the above results, the reaction solutions containing the reaction products obtained from the compound containing epoxy groups having three or more functionalities and the dicarboxylic acid containing a disulfide bond shown in Examples 1 to 4 showed a homogeneous solution state, but the reaction products obtained from the compound containing epoxy groups having three or more functionalities and the dicarboxylic acid containing no disulfide bond shown in Comparative Examples 4 to 6 precipitated insoluble matter in the reaction solution. Therefore, the reaction products obtained in Examples 1 to 4 show high solubility in the reaction solvent (propylene glycol monomethyl ether), which is a resist solvent, and can therefore be suitably used as a resist underlayer film-forming composition.

[0065] [Evaluation of Resist Solvent Resistance] The resist underlayer film forming compositions for lithography prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were applied (spin-coated) onto a silicon wafer using a spin coater. The resist underlayer film was baked (fired) on a hot plate at 215°C or 250°C for 1 minute to form a resist underlayer film with a thickness of 200 nm. An optical interference film thickness meter (Nanospec AFT6100, manufactured by Nanometrics) was used to measure the thickness of the resist underlayer film. Next, in order to confirm the resist solvent resistance of the resist underlayer film formed on the wafer, the formed resist underlayer film was immersed for 1 minute in a solvent in which propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate were mixed at a weight ratio of 7:3, and then spin-dried and baked at 100°C for 30 seconds. The thickness of the resist underlayer film was measured before and after immersion in the mixed solvent. Resist solvent resistance was evaluated by evaluating the film thickness reduction rate (%) of the resist underlayer film removed by solvent immersion using the formula ((film thickness before solvent immersion) - (film thickness after solvent immersion)) ÷ (film thickness before solvent immersion) × 100. It can be said that sufficient resist solvent resistance is obtained when the film thickness reduction rate is approximately 1% or less. The film thickness reduction rate (%) of the resist underlayer film is shown in Table 2.

[0066] [Evaluation of Optical Constants] The resist underlayer film forming compositions for lithography prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were applied (spin coated) onto a silicon wafer using a spin coater. The resist underlayer films were heated on a hot plate at 215°C or 250°C for 1 minute to form films with a thickness of 50 nm. The n value (refractive index) and k value (attenuation coefficient) of these resist underlayer films at a wavelength of 193 nm were measured using a spectroscopic ellipsometer (JA Woolam, VUV-VASE). The results are shown in Table 2.

[0067] [Evaluation of etching selectivity] The resist underlayer film forming compositions for lithography prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were applied onto a silicon wafer and heated at 215°C or 250°C for 1 minute to form a film having a thickness of 200 nm. These were subjected to dry etching with nitrogen gas for 60 seconds using a dry etching apparatus (RIE-10NR) manufactured by Samco Corporation to measure the dry etching rate of the resist underlayer film. The etching selectivity of each underlayer film, assuming that the etching selectivity of the resist underlayer film obtained from Comparative Example 1 is 1, is shown in Table 2.

[0068] [Table 2] From the above results, Examples 1 to 4 exhibit sufficient solvent resistance against resist solvents, and therefore can be suitably used as a resist underlayer film. Furthermore, Examples 1 to 4 have k values ​​at a wavelength of 193 nm, and therefore function as an anti-reflection film that suppresses reflection from the underlayer as a resist underlayer film for lithography. Furthermore, Examples 1 to 4 have sufficiently higher etching selectivity than Comparative Examples 1 to 3, and therefore the resist underlayer film forming composition for lithography obtained by the present invention can shorten the etching time during dry etching of the resist underlayer film, and can suppress the undesirable phenomenon of the resist film thickness decreasing when the resist underlayer film is removed by dry etching. Furthermore, being able to shorten the dry etching time can suppress undesirable etching damage to the substrate underlying the resist underlayer film, and is therefore particularly useful as a resist underlayer film. [Industrial Applicability]

[0069] The resist underlayer film forming composition according to the present invention provides a resist underlayer film having a particularly high dry etching rate.

Claims

1. A resist underlayer film, which is a fired product of a coating film made of a resist underlayer film-forming composition comprising a reaction product of only a dicarboxylic acid having at least one disulfide bond and a trifunctional compound, a surfactant, and a solvent, The resist underlayer film, wherein the trifunctional compound is a compound containing three epoxy groups.

2. The dicarboxylic acid having one or more disulfide bonds is represented by the following formula (1): 【Chemistry 1】 (In formula (1), X １ and X ２ represents an optionally substituted alkylene group having 1 to 10 carbon atoms, an optionally substituted arylene group having 6 to 40 carbon atoms, or a combination thereof.

3. In the formula (1), X １ and X ２ The resist underlayer film according to claim 2, wherein each of the groups is an alkylene group having 1 to 3 carbon atoms.

4. The resist underlayer film according to claim 1 , wherein the trifunctional compound contains a heterocyclic structure.

5. The resist underlayer film according to claim 4 , wherein the heterocyclic structure comprises a triazine structure.

6. The resist underlayer film according to any one of claims 1 to 5, further comprising a crosslinking catalyst.

7. The resist underlayer film according to any one of claims 1 to 6, further comprising a crosslinking agent.

8. A method for forming a resist pattern used in manufacturing a semiconductor device, comprising the steps of: forming a resist underlayer film described in any one of claims 1 to 7 on a semiconductor substrate; applying a resist onto the resist underlayer film and baking it to form a resist film; exposing the resist underlayer film and the semiconductor substrate covered with the resist; and developing the resist film after exposure.

9. A process for forming a resist underlayer film according to any one of claims 1 to 7 on a semiconductor substrate; forming a resist film on the resist underlayer film; forming a resist pattern by irradiating the resist film with light or an electron beam and then developing it; forming a patterned resist underlayer film by etching the resist underlayer film through the formed resist pattern; processing a semiconductor substrate using the patterned resist underlayer film; A method for manufacturing a semiconductor device, comprising:

10. A method for manufacturing a patterned substrate, comprising the steps of: forming a resist underlayer film described in any one of claims 1 to 7 on a semiconductor substrate; applying a resist onto the resist underlayer film and baking to form a resist film; exposing the resist underlayer film and the semiconductor substrate covered with the resist; and developing and patterning the resist film after exposure.

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