WO2011108365A1 - Composition for formation of resist underlayer film which contains fullerene derivative - Google Patents

Abstract

Disclosed is a composition which enables the formation of a resist underlayer film having high etching resistance (a low dry etching rate) and excellent solvent resistance. Specifically disclosed is a composition for forming a resist underlayer film, which comprises a fullerene derivative in which one to six molecules of a malonic acid diester represented by formula (1) (wherein R's independently represent an alkyl group having 1 to 10 carbon atoms) are added per fullerene molecule, a compound having at least two epoxy groups or oxirane rings, and a solvent.

Description

Resist underlayer film forming composition containing fullerene derivative

The present invention relates to a composition for forming a resist underlayer film used in a lithography process when manufacturing a semiconductor device.

In recent years, fullerene derivatives having higher solubility in organic solvents than C ₆₀ fullerene have been synthesized. By using a solution in which such a fullerene derivative is dissolved in an organic solvent, a thin film can be easily formed on a substrate. Therefore, application of fullerene derivatives to n-type organic thin film transistors, solar cells, and the like has been studied.

On the other hand, in a lithography process for manufacturing a semiconductor device, a technique for forming a resist pattern having a desired shape by providing a resist underlayer film prior to forming a photoresist film is known. Patent Document 1 listed below describes a resist underlayer film forming composition prepared using, for example, a fullerene derivative manufactured by Frontier Carbon Co., Ltd. as a fullerene derivative. Patent Document 2 listed below describes a photoresist composition using a diethyl malonate polyadduct or a malonic acid-di-tert-butyl multiadduct as a fullerene derivative. A fullerene derivative as described in Patent Document 2 and a method for producing the fullerene derivative are also described in Patent Document 3 below.

International Publication No. 2008/126804 JP 2005-266798 A JP 2005-26395 A

Control of the dry etching rate is important for the resist underlayer film. For example, in order to increase the etching rate with respect to an oxygen-containing gas and conversely with the etching resistance against a gas containing a fluorine compound such as CF ₄ , it is necessary to employ a resist underlayer film having a high carbon content. . Since fullerene itself is a material composed of only carbon atoms, the carbon content is 100% by mass, but there is a problem that it is difficult to dissolve in a solvent. This problem can be solved by using a fullerene derivative having solubility in a solvent. However, such fullerene derivatives usually have a lower carbon content than fullerenes without a modifying group.

By the way, it has recently been found that the fullerene derivative malonic acid-di-tert-butyl multi-adduct used in Patent Document 2 decomposes the adduct (modifying group) by heating to produce a carboxyl group. . That is, by applying a solution containing a fullerene derivative having the adduct (modifying group) and baking at a temperature at which the adduct (modifying group) decomposes, the carbon content of the formed film is lower than before decomposition. Can be increased.

Further, the resist underlayer film is required not to be dissolved in a solvent contained in the solution to be applied and to be applied uniformly without unevenness when an intermediate layer or a resist film is formed thereon by a coating method.

Therefore, the present invention has an object to provide a composition that can form a resist underlayer film having high etching resistance (low dry etching rate), excellent solvent resistance, and excellent applicability of a solution to be applied thereon. And

（式中、Ｒはそれぞれ独立に炭素原子数１乃至１０のアルキル基を表す。）
で表されるマロン酸ジエステルが１乃至６分子付加したフラーレン誘導体、エポキシ化合物、及び溶剤を含む、レジスト下層膜形成組成物である。 The first aspect of the present invention is:
The following formula (1) for one fullerene molecule:

(In the formula, each R independently represents an alkyl group having 1 to 10 carbon atoms.)
A resist underlayer film forming composition comprising a fullerene derivative to which 1 to 6 molecules of malonic acid diester represented by formula (I) is added, an epoxy compound, and a solvent.

The second aspect of the present invention is:
Applying the resist underlayer film forming composition on a substrate, and baking at least once at a temperature of 180 ° C. to 400 ° C. to form a resist underlayer film;
Applying the intermediate layer forming composition on the resist underlayer film and baking to form a silicon-containing intermediate layer; and
Forming a resist film on the intermediate layer;
It is a method for forming a resist pattern, comprising at least exposing and developing the resist film.

Since the resist underlayer film forming composition of the present invention contains an epoxy compound together with a fullerene derivative that decomposes an adduct (modifying group) by heating, the crosslinking reaction proceeds by baking at a predetermined temperature. As a result, the resist underlayer film to be formed has a high dry etching resistance, a solvent resistance, and a surface with a good solution coating property.

（式中、ｎは１乃至６の整数を表す。）
で表される。しかし、この式（２）で表されるフラーレン誘導体に特定されるわけではない。 The fullerene derivative contained in the resist underlayer film forming composition of the present invention is, for example, the following formula (2) in which R in the formula (1) is a branched alkyl group (3 or more carbon atoms):

(In the formula, n represents an integer of 1 to 6.)
It is represented by However, the fullerene derivative represented by the formula (2) is not specified.

The fullerene derivative contained in the resist underlayer film forming composition of the present invention contains, as a main component, a 4-adduct obtained by adding 4 molecules of a malonic acid diester represented by the formula (1) to 1 molecule of fullerene. it can.

As fullerenes the malonic diester is _added, not only the _{C 60, C 70,} or _{C 60} can use a mixture of the _{C 70,} also used mixtures containing higher fullerenes in addition to _{C 60} and _{C 70} You can also Higher order fullerene is defined herein as a generic term for fullerenes having more than 70 carbon atoms (for example, C ₇₆ , C ₈₂ , C ₈₄ , C ₉₀ and C ₉₆ ). By using the said mixture, cost can be reduced compared with the case where _C60 or _C70 is used.

As the epoxy compound contained in the resist underlayer film forming composition of the present invention, a compound having at least two epoxy groups or oxirane rings is preferable. The epoxy compound is included in the range of, for example, 0.1 to 500% by mass, preferably 1 to 100% by mass with respect to the fullerene derivative.

The resist underlayer film forming composition of the present invention may further contain an acid catalyst or a base catalyst. Examples of the acid catalyst include onium salts, diazomethane derivatives, glyoxime derivatives, bissulfone derivatives, β-ketosulfone derivatives, disulfone derivatives, nitrobenzyl sulfonate derivatives, sulfonate ester derivatives, and sulfonate ester derivatives of N-hydroxyimide compounds. it can. Examples of the base catalyst include imidazole compounds, quaternary ammonium salts, phosphonium salts, amine compounds, aluminum chelate compounds, and organic phosphine compounds. Specifically, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1,8-diaza-bicyclo (5,4,0) undecene-7, trimethylamine, benzyldimethylamine, triethylamine, dimethylbenzylamine, 2 , 4,6-trisdimethylaminomethylphenol and other amine compounds and salts thereof, quaternary ammonium salts such as tetramethylammonium chloride, benzyltrimethylammonium bromide, benzyltriethylammonium chloride, tetrabutylammonium bromide, aluminum chelate, tetra-n And organic phosphine compounds such as -butylphosphonium benzotriazolate and tetra-n-butylphosphonium-o, o-diethyl phosphorodithioate. One kind selected from these acid catalysts or base catalysts may be added, or two or more kinds may be added in combination. The acid catalyst or base catalyst is contained in the fullerene derivative in an amount of, for example, 0.1 to 50% by mass, preferably 0.5 to 40% by mass, and the decomposition reaction of the fullerene derivative adduct (modifying group) and It promotes the crosslinking reaction.

Examples of onium salts are given below. Tetramethylammonium trifluoromethanesulfonate, tetramethylammonium nonafluorobutanesulfonate, triethylammonium nonafluorobutanesulfonate, pyridinium nonafluorobutanesulfonate, triethylammonium camphorsulfonate, diphenyliodonium camphorsulfonate, camphorsulfonic acid (p- tert-Butoxyphenyl) phenyliodonium, camphorsulfonic acid bis (p-tert-butoxyphenyl) iodonium, trifluoromethanesulfonic acid bis (p-tert-butoxyphenyl) iodonium, nonafluorobutanesulfone (p-tert-butoxyphenyl) phenyl Iodonium, nonafluorobutanesulfone bis (p-tert-butoxyphenyl) Donium, pyridinium camphorsulfonate, tetra-n-butylammonium nonafluorobutanesulfonate, tetraphenylammonium nonafluorobutanesulfonate, tetramethylammonium p-toluenesulfonate, pyridinium p-toluenesulfonate, diphenyliodonium trifluoromethanesulfonate, Trifluoromethanesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, p-toluenesulfonic acid diphenyliodonium, p-toluenesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, trifluoromethanesulfonic acid triphenylsulfonium, trifluoromethanesulfone Acid (p-tert-butoxyphenyl) diphenylsulfonium, trifluoromethanesulfuric acid Bis (p-tert-butoxyphenyl) phenylsulfonium acid, tris (p-tert-butoxyphenyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, p-toluenesulfonic acid (p-tert-butoxyphenyl) ) Diphenylsulfonium, bis (p-tert-butoxyphenyl) phenylsulfonium p-toluenesulfonate, tris (p-tert-butoxyphenyl) sulfonium p-toluenesulfonate, triphenylsulfonium nonafluorobutanesulfonate, tributanesulfonate Phenylsulfonium, trimethylsulfonium trifluoromethanesulfonate, trimethylsulfonium p-toluenesulfonate, cyclohexyl trifluoromethanesulfonate Rumethyl (2-oxocyclohexyl) sulfonium, cyclohexylmethyl p-toluenesulfonate (2-oxocyclohexyl) sulfonium, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, p -Toluenesulfonic acid dicyclohexylphenylsulfonium, trifluoromethanesulfonic acid trinaphthylsulfonium, trifluoromethanesulfonic acid (2-norbornyl) methyl (2-oxocyclohexyl) sulfonium, ethylenebis [methyl (2-oxocyclopentyl) sulfonium trifluoromethanesulfonate] 1,2, '-naphthylcarbonylmethyltetrahydrothiophene Um triflate, triethylammonium nonaflate, tributylammonium nonaflate, tetraethylammonium nonaflate, tetrabutylammonium nonaflate, triethylammonium bis (trifluoromethyl) imide, and triethylammonium tris (perfluoroethyl sulfonyl) methide.

Examples of diazomethane derivatives are shown below. Bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (xylenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (cyclopentylsulfonyl) diazomethane, bis (n-butylsulfonyl) diazomethane, bis (isobutylsulfonyl) ) Diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis (n-amylsulfonyl) diazomethane, bis (isoamylsulfonyl) ) Diazomethane, bis (sec-amylsulfonyl) diazomethane, bis (tert-amylsulfonyl) diazomethane, 1-silane B hexylsulfonyl-1-(tert-butylsulfonyl) diazomethane, 1-cyclohexyl sulfonyl-1-(tert-amylsulfonyl) diazomethane and 1-tert-amylsulfonyl-1-(tert-butylsulfonyl) diazomethane.

Examples of glyoxime derivatives are shown below. Bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime, bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime, bis-O- (p-toluenesulfonyl) -α-dicyclohexylglyoxime Bis-O- (p-toluenesulfonyl) -2,3-pentanedione glyoxime, bis-O- (p-toluenesulfonyl) -2-methyl-3,4-pentanedione glyoxime, bis-O- ( n-butanesulfonyl) -α-dimethylglyoxime, bis-O- (n-butanesulfonyl) -α-diphenylglyoxime, bis-O- (n-butanesulfonyl) -α-dicyclohexylglyoxime, bis-O— (N-butanesulfonyl) -2,3-pentanedione glyoxime, bis-O- (n-butanesulfonyl) -2- Tyl-3,4-pentanedione glyoxime, bis-O- (methanesulfonyl) -α-dimethylglyoxime, bis-O- (trifluoromethanesulfonyl) -α-dimethylglyoxime, bis-O- (1,1 , 1-trifluoroethanesulfonyl) -α-dimethylglyoxime, bis-O- (tert-butanesulfonyl) -α-dimethylglyoxime, bis-O- (perfluorooctanesulfonyl) -α-dimethylglyoxime, bis -O- (cyclohexanesulfonyl) -α-dimethylglyoxime, bis-O- (benzenesulfonyl) -α-dimethylglyoxime, bis-O- (p-fluorobenzenesulfonyl) -α-dimethylglyoxime, bis-O -(P-tert-butylbenzenesulfonyl) -α-dimethylglyoxime, Scan -O- (xylene sulfonyl)-.alpha.-dimethylglyoxime and bis -O- (camphorsulfonyl),-.alpha.-dimethylglyoxime.

Examples of bissulfone derivatives are shown below. Bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane, bisethylsulfonylmethane, bispropylsulfonylmethane, bisisopropylsulfonylmethane, bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane.

Examples of β-ketosulfone derivatives are shown below. 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane and 2-isopropylcarbonyl-2- (p-toluenesulfonyl) propane.

Examples of disulfone derivatives are shown below. Diphenyl disulfone derivatives and dicyclohexyl disulfone derivatives.

Nitrobenzyl sulfonate derivatives are exemplified below. 2,6-dinitrobenzyl p-toluenesulfonate and 2,4-dinitrobenzyl p-toluenesulfonate.
Examples of the sulfonate ester derivative are shown below. 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, and 1,2,3-tris (p-toluenesulfonyloxy) benzene.

Examples of sulfonic acid ester derivatives of N-hydroxyimide compounds are shown below. N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester, N-hydroxysuccinimide ethanesulfonic acid ester, N-hydroxysuccinimide 1-propanesulfonic acid ester, N-hydroxysuccinimide 2-propanesulfonic acid ester, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide 1-octanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxysuccinimide p-methoxybenzenesulfonic acid ester, N-hydroxysuccinimide 2 -Chloroethane sulfonate, N-hydroxysuccinimide benzene sulfonate, N- Droxysuccinimide-2,4,6-trimethylbenzenesulfonic acid ester, N-hydroxysuccinimide 1-naphthalenesulfonic acid ester, N-hydroxysuccinimide 2-naphthalenesulfonic acid ester, N-hydroxy-2-phenylsuccinimide methanesulfonic acid ester N-hydroxymaleimide methanesulfonate, N-hydroxymaleimide ethanesulfonate, N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimide methanesulfonate, N-hydroxyglutarimide benzenesulfonate Esters, N-hydroxyphthalimide methanesulfonate, N-hydroxyphthalimidebenzenesulfonate, N-hydroxyphthalate Imidotrifluoromethanesulfonic acid ester, N-hydroxyphthalimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, N-hydroxy-5-norbornene-2,3- Dicarboximide methane sulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide trifluoromethane sulfonate, and N-hydroxy-5-norbornene-2,3-dicarboximide p-toluene sulfonate ester.

The resist underlayer film forming composition of the present invention can further contain a surfactant. As the surfactant, for example, Ftop (registered trademark) EF301, EF303, EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), MegaFuck (registered trademark) F171, F173, R173 (manufactured by DIC Corporation), Fluorard FC430, FC431 (Sumitomo 3M Co., Ltd.), Asahi Guard (registered trademark) AG710, Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.) Fluorosurfactant such as a company) and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). One kind selected from these surfactants may be added, or two or more kinds may be added in combination. The surfactant is contained in the range of, for example, 0.01 to 10% by mass, preferably 0.1 to 5% by mass with respect to the fullerene derivative.

The resist underlayer film forming composition of the present invention is used in a uniform solution state in which each of the above components is dissolved in a solvent. Examples of such solvents include propylene glycol monomethyl ether acetate, cyclohexanone, 2-heptanone, ethyl lactate, o-xylene, toluene, o-dichlorobenzene, propylene glycol monomethyl ether, propylene glycol monopropyl ether, 1-methyl-2 -Pyrrolidone and γ-butyrolactone can be used. One kind selected from these solvents may be used, or two or more kinds may be used in combination.

The prepared resist underlayer film forming composition is preferably used after being filtered using, for example, a filter having a pore size smaller than 0.1 μm or 0.1 μm. The resist underlayer film-forming composition after filtration is excellent in long-term storage stability at room temperature.

Hereinafter, the method of using the resist underlayer film forming composition of the present invention will be described. Substrate [for example, a semiconductor substrate such as silicon on which a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed, a silicon nitride substrate, a quartz substrate, a glass substrate (including non-alkali glass, low alkali glass, and crystallized glass) The resist underlayer film forming composition of the present invention is applied onto a glass substrate on which an ITO film is formed by an appropriate application method such as a spinner or a coater, and then baked using a heating means such as a hot plate. By doing so, a resist underlayer film is formed. As the baking conditions, the optimum value is selected from the range of temperature: 180 ° C. to 400 ° C. and time: 0.3 minutes to 10 minutes. After baking at a temperature of 180 ° C. to 250 ° C., baking may be performed again at a temperature higher than the temperature, for example, 300 ° C. to 400 ° C. By baking at a temperature of 180 ° C. to 250 ° C., the adduct (modifying group) of the fullerene derivative contained in the applied composition is decomposed to generate a carboxyl group. It is presumed that the adduct (modifying group) is further decomposed by baking at 300 ° C. to 400 ° C., and the fullerene derivative undergoes a crosslinking reaction. The thickness of the resist underlayer film to be formed is 0.01 μm to 3.0 μm, for example, 0.03 μm to 1.0 μm, or 0.05 μm to 0.5 μm.

The intermediate layer forming composition is applied onto the resist underlayer film by an appropriate application method such as a spinner or a coater. Examples of the intermediate layer forming composition include a solution containing one or two or more alkoxysilane hydrolyzates and / or hydrolysis condensates and necessary additives, or a commercially available polysilane and necessary additives. A solution. Thereafter, the silicon-containing intermediate layer is formed by baking using a heating means such as a hot plate. As the baking conditions, an optimum value is selected from the range of temperature: 180 ° C. to 300 ° C. and time: 0.3 minutes to 10 minutes.

Next, a resist film is formed on the silicon-containing intermediate layer. The resist film can be formed by a general method, that is, by applying a resist solution onto the intermediate layer and baking. The resist solution to be used is not particularly limited. For example, Rohm and Haas Electronic Materials, trade name: APEX-E, Sumitomo Chemical Co., trade name: PAR710, and Shin-Etsu Chemical Co., Ltd. Product name: SEPR430 etc. are mentioned.

Further, exposure is performed through a photomask (reticle) in order to form a resist pattern from the resist film. For the exposure, for example, a KrF excimer laser, an ArF excimer laser, and EUV (extreme ultraviolet) can be used. After exposure, PEB (Post Exposure Bake) is performed as necessary, and then development is performed.

When using a positive resist solution, an alkaline developer is used for development. Examples of alkaline developers include aqueous solutions of alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and choline, ethanolamine, and propyl. Examples of the amine aqueous solution include amines and ethylenediamine. Further, a surfactant can be added to these developers.

The development conditions are appropriately selected from a development temperature of 5 ° C. to 50 ° C. and a development time of 10 seconds to 300 seconds. In the case of the present invention, development can be easily performed at room temperature using a 2.38 mass% aqueous tetramethylammonium hydroxide solution that is widely used for developing photoresists.

Hereinafter, specific examples of the present invention will be described with reference to the following synthesis examples and examples. However, the present invention is not limited thereto.

(Synthesis Example 1)
Under a nitrogen stream, 9.80 g of malonate-di-tert-butyl (manufactured by Aldrich) was placed in a reaction vessel, and 150 cm ^{3 of} 1,2,4-trimethylbenzene and diazabicyclo [5.4.0] -7-undecene ( 6.50 g of 1,8-diazabiccyclo [5.4.0] undec-7-ene, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and the temperature was adjusted to 4 ° C. while stirring.

A black-violet solution in which 10.9 g of iodine (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 130 cm ³ of 1,2,4-trimethylbenzene was slowly added dropwise to the resultant reaction liquid after temperature adjustment. During the dropping, the temperature inside the flask was controlled to 11 ° C. using an ice bath. After completion of dropping, the temperature of the reaction solution was returned to room temperature. The reaction solution in the flask was in the form of a brown suspension.

Thereafter, 5.00 g of a fullerene mixture (including C ₆₀ , C ₇₀ and other higher-order fullerenes, manufactured by Frontier Carbon Co., Ltd.) is dissolved in 350 cm ³ of 1,2,4-trimethylbenzene in the reaction liquid in the reaction vessel. The solution was added with stirring. Here, higher order fullerene is defined in this specification as a general term for fullerene having more than 70 carbon atoms. Thereafter, 6.90 g of diazabicyclo [5.4.0] -7-undecene (1,8-diazabicyclo [5.4.0] undec-7-ene, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction solution in the flask. Was slowly added dropwise with stirring to a solution diluted with 5 cm ³ of 1,2,4-trimethylbenzene. The reaction was allowed to stir at room temperature for 6.5 hours.

About the obtained reaction liquid, the reaction layer (organic phase) was wash | cleaned 4 times by saturated sodium sulfite aqueous solution. The obtained organic phase was washed twice with 100 cm ³ of 1N sulfuric acid aqueous solution and then washed three times with 200 cm ³ of pure water. The solvent (1,2,4-trimethylbenzene) was distilled off under reduced pressure to obtain 9.50 g of a reddish brown solid.

The obtained solid was fractionated with a mixed solvent of n-hexane and ethyl acetate by silica gel chromatography to obtain a fullerene derivative (malonic acid-di-tert-butyl ester adduct).

Example 1
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.15 g of an epoxy compound represented by the formula (3-a) (trade name: YH434L, manufactured by Tohto Kasei Co., Ltd.), Megafac as a surfactant [registered trademark] ] 0.001 g of R-30 (DIC Corporation) was mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution.

(Example 2)
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.3 g of the epoxy compound used in Example 1 (trade name: YH434L, manufactured by Tohto Kasei Co., Ltd.), Megafac [registered trademark] R-30 as a surfactant 0.001 g (manufactured by DIC Corporation) was mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution. In this example, the mass of the epoxy compound used is different from that of Example 1 described above.

(Example 3)
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.1 g of an epoxy compound represented by the formula (3-b) (manufactured by Daicel Chemical Industries, Ltd., trade name: GT401), Megafac as a surfactant [Registered] Trademark] 0.001 g of R-30 (manufactured by DIC Corporation) was mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution.

Example 4
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.2 g of an epoxy compound represented by the formula (3-c) (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: TETRAD-C), Megafac as a surfactant [Registered Trademark] 0.001 g of R-30 (manufactured by DIC Corporation) was mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution.

(Example 5)
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.3 g of an epoxy compound represented by the formula (3-d) (manufactured by DIC Corporation, trade name: HP-4700), Megafac as a surfactant [Registered] Trademark] 0.001 g of R-30 (manufactured by DIC Corporation) was mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution.

(Example 6)
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.15 g of the epoxy compound represented by the above formula (3-a) (manufactured by Tohto Kasei Co., Ltd., trade name: YH434L), Megafac as a surfactant [Registered] Trademark] 0.001 g of R-30 (DIC Corporation) and 0.05 g of pyridinium p-toluenesulfonate as a catalyst were mixed and dissolved in 7.0 g of propylene glycol monomethyl ether acetate to obtain a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution.

(Comparative Example 1)
To 1.0 g of the fullerene derivative obtained in Synthesis Example 1, 0.001 g of MegaFace [registered trademark] R-30 (manufactured by DIC Corporation) is mixed as a surfactant and dissolved in 7.0 g of propylene glycol monomethyl ether acetate. It was set as the solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and also filtered using the polyethylene micro filter with the hole diameter of 0.05 micrometer, and prepared the resist underlayer film forming composition solution. This comparative example is an example that does not contain an epoxy compound, unlike the above-described Examples 1 to 6.

[Elution test in photoresist solvent]
Each resist underlayer film forming composition solution (including an epoxy compound) prepared in Examples 1 to 6 was applied onto a silicon wafer by a spinner. Heating was performed on a hot plate at a temperature of 240 ° C. for 1 minute to form a resist underlayer film (film thickness 0.2 μm). Then, these resist underlayer films were immersed in ethyl lactate, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, which are solvents used for the photoresist, and confirmed to be insoluble in the solvent.

Next, the resist underlayer film forming composition solution prepared in Comparative Example 1 was applied onto a silicon wafer by a spinner. Heating was performed on a hot plate at a temperature of 240 ° C. for 1 minute to form a resist underlayer film (film thickness 0.2 μm). When this resist underlayer film was immersed in ethyl lactate, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, which are solvents used for the photoresist, it was confirmed that it was dissolved in the solvent. Since the film coated with the resist underlayer film forming composition prepared in Comparative Example 1 does not exhibit solvent resistance by the heating, an intermediate layer forming material (for example, poly It is difficult to form a film containing a composition containing siloxane or polysilane.

[Optical parameter test]
Each resist underlayer film forming composition prepared in Examples 1 to 6 and Comparative Example 1 was applied onto a silicon wafer by a spinner. Heating was performed on a hot plate at a temperature of 240 ° C. for 1 minute to form a resist underlayer film (film thickness 0.2 μm). These resist underlayer films were subjected to a refractive index (n value) and optical absorption coefficient (k value, attenuation coefficient) at a wavelength of 193 nm using a spectroscopic ellipsometer (manufactured by JA Woollam, VUV-VASE VU-302). (Also called). The results are shown in Table 1 below.

The results shown in Table 1 indicate that when a resist underlayer film obtained from the resist underlayer film forming composition according to the present invention is used in combination with a silicon-containing intermediate layer, the reflection of light having a wavelength of 193 nm from the substrate is reduced. It has n value and k value which can be.

[Measurement of dry etching rate]
The following etching apparatus and etching gas were used for the measurement of the dry etching rate.
Etching device: RIE-10NR (manufactured by Samco Corporation)
Etching gas: CF ₄
Each resist underlayer film forming composition solution prepared in Examples 1 to 6 and Comparative Example 1 was applied onto a silicon wafer by a spinner. Heating was performed on a hot plate at a temperature of 240 ° C. for 1 minute to form a resist underlayer film (film thickness 0.2 μm). The dry etching rate was measured for the resist underlayer film using CF ₄ gas as an etching gas. Further, a solution obtained by dissolving 0.7 g of phenol novolak resin in 10 g of propylene glycol monomethyl ether was applied onto a silicon wafer by a spinner and heated at a temperature of 240 ° C. for 1 minute to form a phenol novolak resin film. With respect to the resin film, the dry etching rate was measured using CF ₄ gas as an etching gas, and each of the resist underlayer films formed from the resist underlayer film forming compositions of Examples 1 to 6 and Comparative Example 1 was measured. Comparison with dry etching rate was performed. The results are shown in Table 2 below. The dry etching rate ratio in Table 2 is the dry etching rate of each resist underlayer film (resist underlayer film) / (phenol novolac resin film) with respect to the dry etching rate of the phenol novolak resin film.

From the results of Table 2 above, the resist underlayer film obtained from the resist underlayer film forming composition containing the catalyst prepared in Example 6 is the resist obtained from the resist underlayer film forming composition prepared in other Examples. Compared to the lower layer film, the dry etching rate ratio was small. This result has shown that the dry etching tolerance of the film | membrane formed improves, when a resist underlayer film forming composition contains a catalyst.

Claims (4)

The following formula (1) for one fullerene molecule:

(In the formula, each R independently represents an alkyl group having 1 to 10 carbon atoms.)
A resist underlayer film forming composition comprising: a fullerene derivative to which 1 to 6 molecules of malonic acid diester represented by formula 1 is added; a compound having at least two epoxy groups or oxirane rings; and a solvent. Furthermore, the resist underlayer film forming composition of Claim 1 containing an acid catalyst or a base catalyst. Furthermore, the resist underlayer film forming composition of Claim 1 or Claim 2 containing surfactant. Applying the resist underlayer film forming composition according to any one of claims 1 to 3 on a substrate, and baking at least once at a temperature of 180 ° C to 400 ° C to form a resist underlayer film; ,
Applying the intermediate layer forming composition on the resist underlayer film and baking to form a silicon-containing intermediate layer; and
Forming a resist film on the intermediate layer;
A method for forming a resist pattern, comprising: exposing and developing at least the resist film.