JP2005241963A - Composition for forming antireflection film and antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming an antireflection film from which a resist pattern having excellent dry etching durability, a high antireflection effect and excellent resolution and accuracy without causing intermixing can be formed, and to provide an antireflection film formed by using the above composition. <P>SOLUTION: The composition for forming an antireflection film contains a polymer obtained from at least one kind of compound expressed by formula (3) or formula (4) and at least one kind of fullerene compound selected from a group (B) consisting of fullerenes and fullerene derivatives. In formulae, R<SP>1</SP>independently represents a hydrogen atom, a fluorine atom or a monovalent group; R<SP>4</SP>represents a halogen atom or a monovalent group; and each of R<SP>5</SP>, R<SP>6</SP>and R<SP>7</SP>independently represents a hydrogen atom, a halogen atom or a monovalent group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composition for forming an antireflection film that is useful for microfabrication in a lithography process using various types of radiation, and is particularly suitable for manufacturing integrated circuit elements, and an antireflection film formed using this composition.

  In the manufacturing method of an integrated circuit element, in order to obtain a higher degree of integration, the processing size in the lithography process is miniaturized. In this lithography process, a liquid resist composition is applied onto a substrate, a mask pattern is transferred by a reduction projection exposure apparatus (stepper), and developed with an appropriate developer to obtain a desired pattern. However, highly reflective substrates such as aluminum, aluminum-silicon alloys, aluminum-silicon-copper alloys, polysilicon, tungsten silicide, etc. used in this process reflect the irradiated radiation at the surface. As a result, there is a problem that halation occurs in the resist pattern and a fine resist pattern cannot be accurately reproduced.

  In order to solve this problem, it has been proposed to provide an antireflection film having a property of absorbing radiation reflected from the substrate under the resist film to be formed on the substrate. As such an antireflection film, an inorganic film such as a titanium film, a titanium dioxide film, a titanium nitride film, a chromium oxide film, a carbon film, or an α-silicon film formed by a method such as vacuum deposition, CVD, or sputtering. However, since these inorganic antireflection films have electrical conductivity, they cannot be used in the production of integrated circuits, or special anti-reflection films such as vacuum deposition equipment, CVD equipment, and sputtering equipment are used to form antireflection films. There were drawbacks such as requiring a simple device. In order to solve the disadvantages of this inorganic antireflection film, an organic antireflection film comprising a polyamic acid (co) polymer or polysulfone (co) polymer and a dye has been proposed (Patent Document 1). This antireflection film has no electrical conductivity, and the composition constituting the antireflection film is dissolved in an appropriate solvent. Therefore, a special apparatus is not required and the solution is formed on the substrate in the same state as the resist. Can be applied.

  However, an antireflection film comprising a polyamic acid (co) polymer or a polysulfone (co) polymer and a dye cannot sufficiently prevent halation and standing waves because the amount of the dye added is limited. However, there is a problem that the resist pattern cross-sectional shape (pattern profile) such as omission failure and tailing is deteriorated.

  On the other hand, it is known that the use of a thermally oxidized novolac resin as an antireflection film can considerably solve the above-mentioned problems. However, when a pattern is transferred to an insulating film in further fine etching processing in the future. The problem of dimensional conversion differences caused by insufficient etching resistance has not been sufficiently solved.

Therefore, it has been desired to develop an improved antireflection film for solving such problems in the prior art and a polymer particularly useful in the formation of such an antireflection film.
JP 59-93448 A

The present invention is intended to solve the problems associated with the prior art as described above, is excellent in dry etching resistance, has a high antireflection effect, and does not cause intermixing.
An object of the present invention is to provide a composition for forming an antireflection film capable of forming a resist pattern excellent in resolution and accuracy, and an antireflection film formed using this composition.

  The present inventor has eagerly studied to solve the above problems, and uses a polymer obtained from a vinyl group-containing compound and a fullerene compound as an antireflection film, thereby providing a conventional coating-type lower antireflection film and As a result, it was found that an antireflection film having excellent dry etching resistance and high absorbance with respect to excimer laser light was obtained, and the present invention was completed.

That is, the composition for forming an antireflection film according to the present invention is
It contains a polymer having a repeating unit (a-1) represented by the following formula (1) and a repeating unit (b) having a fullerene structure.

In the formula (1), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represent a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Show.

In addition, the composition for forming an antireflection film according to the present invention comprises:
It is characterized by containing a polymer having a repeating unit (a-2) represented by the following formula (2) and a repeating unit (b) having a fullerene structure.

In the formula (2), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom or a monovalent group.

Furthermore, the composition for forming an antireflection film according to the present invention comprises:
Selected from the group consisting of at least one compound (A-1) represented by the following formula (3) or at least one compound (A-2) represented by the following formula (4), fullerene and a fullerene derivative It is characterized by containing a polymer obtained by mixing at least one fullerene compound (B) and heating in the presence of a radical initiator.

In the formula (3), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represent a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Show.

In the formula (4), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom or a monovalent group.

  The antireflection film-forming composition preferably further contains a crosslinking agent (C), and preferably further contains an acid generator (D).

  The antireflection film according to the present invention is formed by heating a coating film formed using the above composition at 150 to 350 ° C.

  The composition for forming an antireflection film according to the present invention can form an antireflection film that has excellent dry etching resistance, a high antireflection effect, and does not cause intermixing with a resist. The antireflection film according to the present invention can form a resist pattern having excellent resolution and accuracy in cooperation with positive and negative resists.

[Composition for forming antireflection film]
The composition for forming an antireflective film according to the present invention contains a polymer obtained by mixing a specific compound having a vinyl group and a fullerene compound and then heating.

<Compound having vinyl group (A)>
<Compound having vinyl group (A-1)>
The compound (A-1) (hereinafter simply referred to as “compound (A-1)”) having a vinyl group used in the present invention is a compound represented by the following formula (3).

In the above formula (3), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represent a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Indicates.

The monovalent group in R ² and R ³ is preferably a group having 1 to 20 carbon atoms, specifically, an alkyl group, an alkenyl group, an acyl group, a cyano group, an ester group, a hydroxyl group, a mercapto group, an amino group. , Carboxyl group, sulfonic acid group, phenyl group, naphthyl group, anthranyl group; alkenyl group, phenyl group, naphthyl group, anthranyl group as halogen atom, hydroxyl group, mercapto group, carboxyl group, nitro group, sulfonic acid group, hydroxymethyl And a group substituted with at least one atom or substituent selected from a group, a methoxymethyl group, an ethoxymethyl group, and the like.

  The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and more preferably a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i- A butyl group, a sec-butyl group, a t-butyl group, etc. can be mentioned.

  The alkenyl group is preferably a linear or branched alkenyl group having 2 to 6 carbon atoms, more preferably a vinyl group, an allyl group, a methacryl group, a 1-butenyl group, a 2-butenyl group, or the like. it can.

  The acyl group is preferably an aliphatic or aromatic acyl group having 2 to 6 carbon atoms, and more preferably an acetyl group, a propionyl group, a butyryl group, a benzoyl group, and the like.

  The ester group is preferably an aliphatic or aromatic ester group having 2 to 20 carbon atoms, more preferably a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, an i-butoxycarbonyl group, a tert-butoxycarbonyl group, A phenoxycarbonyl group, a benzyloxycarbonyl group, etc. can be mentioned.

Examples of the halogen atom for R ⁴ include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom.

Examples of the monovalent group in R ⁴ include the same groups as those exemplified for the monovalent group in R ² and R ³ .

In the above formula (3), R ¹ is particularly preferably a hydrogen atom. R ² and R ³ are each independently preferably a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a methoxycarbonyl group, a cyano group, a phenyl group, or the like. R ⁴ includes methyl group, ethyl group, cyano group, amino group, methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, methylcarbooxy group, phenyl group, naphthyl group, anthranyl group, hydroxymethylphenyl group, A hydroxymethylnaphthyl group, a methoxymethylphenyl group, a methoxymethylnaphthyl group and the like are preferable.

As a specific compound represented by the above formula (3), for example,
Styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-hydroxymethylstyrene, 3-hydroxymethylstyrene, 4-methoxymethylstyrene, 3-methoxymethylstyrene, 1-vinylnaphthalene 2-vinylnaphthalene, 1-vinyl-4-hydroxymethylnaphthalene, 1-vinyl-5-hydroxymethylnaphthalene, 1-vinyl-6-hydroxymethylnaphthalene, 2-vinyl-4-hydroxymethylnaphthalene, 2-vinyl- Aromatic vinyl compounds such as 6-hydroxymethylnaphthalene, 9-vinylanthracene and 9-vinylcarbazole;
Vinyl ester compounds such as vinyl acetate, vinyl propionate and vinyl caproate;
Vinyl cyanide compounds such as (meth) acrylonitrile, α-chloroacrylonitrile, vinylidene cyanide;
Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, glycidyl (meth) acrylate, etc. An unsaturated carboxylic acid ester compound of
Unsaturated group-containing unsaturated carboxylic acid ester compounds such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, vinyl (meth) acrylate, dimethyl vinyl (meth) acryloyloxymethylsilane;
Halogen-containing vinyl compounds such as 2-chloroethyl vinyl ether, vinyl chloroacetate and allyl chloroacetate;
Hydroxyl group-containing vinyl compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and (meth) allyl alcohol;
Amide group-containing vinyl compounds such as (meth) acrylamide and crotonic acid amide;
Succinic acid mono [2- (meth) acryloyloxyethyl], maleic acid mono [2- (meth) acryloyloxyethyl], phthalic acid mono [2- (meth) acryloyloxyethyl], dimethyl itaconate, diethyl itaconate, Carboxyl group-containing vinyl compounds such as dimethyl maleate and diethyl maleate;
Amine-containing vinyl compounds such as vinylamine and allylamine;
Chlorotrifluoroethylene, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, Examples thereof include fluorine-containing vinyl compounds such as 2- (perfluorohexyl) ethyl (meth) acrylate.

  The said compound (A-1) can be used individually or in mixture of 2 or more types.

<Compound having vinyl group (A-2)>
The compound (A-2) having a vinyl group used in the present invention (hereinafter simply referred to as “compound (A-2)”) is a compound represented by the following formula (4).

In the above formula (4), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom or a monovalent group.

  Preferred examples of the halogen atom include fluorine, chlorine, and bromine.

  Examples of the monovalent group include an alkyl group, an alkenyl group, a nitro group, an amino group, a hydroxyl group, a phenyl group, an acyl group, a carboxyl group, a sulfonic acid group, and a mercapto group.

  The alkyl group is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and the like.

  The alkenyl group is preferably a linear or branched alkenyl group having 2 to 6 carbon atoms, and examples thereof include vinyl and allyl.

  The acyl group is preferably an aliphatic or aromatic acyl group having 1 to 6 carbon atoms, and examples thereof include an acetyl group.

  As the amino group, a primary amino group is preferable.

  Specific compounds (acenaphthylenes) represented by the above formula (4) include, for example, acenaphthylene, hydroxymethyl acenaphthylenes, acetoxymethyl acenaphthylenes, and methoxymethyl acenaphthylenes.

Examples of hydroxymethyl acenaphthylenes include 3-hydroxymethyl acenaphthylene, 4-hydroxymethyl acenaphthylene, 5-hydroxymethyl acenaphthylene, 1-methyl-3-hydroxymethyl acenaphthylene, 1-methyl-4. -Hydroxymethylacenaphthylene, 1-methyl-5-hydroxymethylacenaphthylene, 1-methyl-6-hydroxymethylacenaphthylene, 1-methyl-7-hydroxymethylacenaphthylene, 1-methyl-8-hydroxy Methyl acenaphthylene, 1,2-dimethyl-3-hydroxymethyl acenaphthylene, 1,2-dimethyl-4-hydroxymethyl acenaphthylene, 1,2-dimethyl-5-hydroxymethyl acenaphthylene, 1-phenyl -3-hydroxymethylacenaphthylene, 1-phenyl-4 Hydroxymethylacenaphthylene, 1-phenyl-5-hydroxymethylacenaphthylene, 1-phenyl-6-hydroxymethylacenaphthylene, 1-phenyl-7-hydroxymethylacenaphthylene, 1-phenyl-8-hydroxymethyl Examples include acenaphthylene, 1,2-diphenyl-3-hydroxymethylacenaphthylene, 1,2-diphenyl-4-hydroxymethylacenaphthylene, 1,2-diphenyl-5-hydroxymethylacenaphthylene, and the like.

  Examples of acetoxymethyl acenaphthylenes include 3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene, 5-acetoxymethyl acenaphthylene, 1-methyl-3-acetoxymethyl acenaphthylene, 1-methyl-4 -Acetoxymethyl acenaphthylene, 1-methyl-5-acetoxymethyl acenaphthylene, 1-methyl-6-acetoxymethyl acenaphthylene, 1-methyl-7-acetoxymethyl acenaphthylene, 1-methyl-8-acetoxy Methyl acenaphthylene, 1,2-dimethyl-3-acetoxymethyl acenaphthylene, 1,2-dimethyl-4-acetoxymethyl acenaphthylene, 1,2-dimethyl-5-acetoxymethyl acenaphthylene, 1-phenyl -3-Acetoxymethylacenaphthylene, 1-phenyl-4 Acetoxymethyl acenaphthylene, 1-phenyl-5-acetoxymethyl acenaphthylene, 1-phenyl-6-acetoxymethyl acenaphthylene, 1-phenyl-7-acetoxymethyl acenaphthylene, 1-phenyl-8-acetoxymethyl Examples include acenaphthylene, 1,2-diphenyl-3-acetoxymethyl acenaphthylene, 1,2-diphenyl-4-acetoxymethyl acenaphthylene, 1,2-diphenyl-5-acetoxymethyl acenaphthylene, and the like.

  Examples of methoxymethyl acenaphthylenes include 3-methoxymethyl acenaphthylene, 4-methoxymethyl acenaphthylene, 5-methoxymethyl acenaphthylene, 1-methyl-3-methoxymethyl acenaphthylene, 1-methyl-4. -Methoxymethylacenaphthylene, 1-methyl-5-methoxymethylacenaphthylene, 1-methyl-6-methoxymethylacenaphthylene, 1-methyl-7-methoxymethylacenaphthylene, 1-methyl-8-methoxy Methyl acenaphthylene, 1,2-dimethyl-3-methoxymethyl acenaphthylene, 1,2-dimethyl-4-methoxymethyl acenaphthylene, 1,2-dimethyl-5-methoxymethyl acenaphthylene, 1-phenyl -3-methoxymethyl acenaphthylene, 1-phenyl-4-methoxymethyl acenaphthylene 1-phenyl-5-methoxymethyl acenaphthylene, 1-phenyl-6-methoxymethyl acenaphthylene, 1-phenyl-7-methoxymethyl acenaphthylene, 1-phenyl-8-methoxymethyl acenaphthylene, , 2-diphenyl-3-methoxymethyl acenaphthylene, 1,2-diphenyl-4-methoxymethyl acenaphthylene, 1,2-diphenyl-5-methoxymethyl acenaphthylene, and the like.

  In addition to the acenaphthylenes exemplified above, 3-phenoxymethyl acenaphthylene, 4-phenoxymethyl acenaphthylene, 5-phenoxymethyl acenaphthylene, 3-vinyloxymethyl acenaphthylene, 4-vinyloxymethyl acenaphthylene , 5-vinyloxymethylacenaphthylene and the like.

  Among these acenaphthylenes, in particular, acenaphthylene, 3-hydroxymethyl acenaphthylene, 4-hydroxymethyl acenaphthylene, 5-hydroxymethyl acenaphthylene, 3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene 5-acetoxymethyl acenaphthylene, 3-methoxymethyl acenaphthylene, 4-methoxymethyl acenaphthylene, 5-methoxymethyl acenaphthylene and the like are preferable.

  The acenaphthylenes can be used singly or in combination of two or more.

<Fullerene compound (B)>
In the present invention, the fullerene compound is used for preventing intermixing between the antireflection film and the resist film formed thereon. The fullerene compound also plays a role in preventing the occurrence of cracks after the application of the composition for forming an antireflection film.

As the fullerene compound (B) used in the present invention, fullerene C ₃₅ , C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₅ , carboxyl group-substituted fullerene C ₆₀ , carboxyl group-substituted fullerene C _70, methoxycarbonyl substituted fullerene C _60, methoxycarbonyl substituted fullerene C _70, hydrogenated fullerene C _60, hydrogenated fullerene C _70, alkyl-substituted fullerene C _60, and the like alkyl-substituted fullerene C _70.

These fullerenes can be synthesized by known methods. For example, a method for producing fullerene C ₃₆ is described in New Diamond. , Vol. 16, no. 2, 2000, p. 30-31. As a method for producing fullerenes C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ and C ₉₆ , J. Phy. Chem. , 94, 8634 (1990), a manufacturing method using an arc discharge method is disclosed in Z. Phys. D, 40, 414 (1997) disclose a production method by an oven laser method. Higher order fullerene having more than 96 carbon atoms in one molecule and a maximum aggregate diameter of 30 nm or less can be obtained as a by-product of the arc discharge method.

Commercial products of fullerenes C ₆₀ and C ₇₀ include fullerenes such as those manufactured by Frontier Carbon Co., Ltd. and MATERIALS TECHNOLOGIES RESEARCH MTR LIMITED. Commercial products of fullerenes C ₇₆ , C ₇₈ and C ₈₄ include MATERIALS TECHNOLOGIES. Fullerenes such as those manufactured by RESEARCH MTR LIMITED may be mentioned.

The fullerene compound (B) used in the present invention can achieve the object of the present invention even if it is one kind of fullerene or a mixture of fullerenes having different carbon numbers. Examples of commercially available products of the mixture, a mixture of Frontier Carbon Corp. or MATERIALS TECHNOLOGIES RESEARCH MTR LIMITED Co. fullerene C ₆₀ / C ₇₀ and the like.

  In the present invention, a fullerene derivative can also be used as the fullerene compound (B). Examples of fullerene derivatives include functional group-containing fullerene derivatives and heterocyclic-containing fullerene derivatives.

The functional group-containing fullerene derivative has an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a carboxyl group, a hydroxyl group, an epoxy group, and an amino group on the surface of the fullerene. It has a functional group such as Among these, an amino group is represented by —NR ⁸ ₂ , and each R ⁸ is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 2 to 6 carbon atoms. An alkynyl group or a polyether chain having a molecular weight of 30 to 50,000 is preferred. In the amino group, when R ⁸ is a polyether chain, the terminal is preferably a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms.

Functional group-containing fullerene derivatives are described, for example, in Science, 252, 548 (1991) and J. Org. Am. Chem. Soc, 114, 1103 (1992), Angew. Chem. Int. Ed. Engl. , 30, 1309 (1991), addition reactions of primary or secondary amines, J. Org. Am. Chem. Soc, 114, 7301 (1992), or the Diels-Alder reaction, Chem. Soc. , Chem. Commun. 1791 (1992), and can be synthesized by a known method such as a polyhydroxylation reaction.

  The heterocycle-containing fullerene derivative is a fullerene derivative in which a group having a heterocycle is bonded to fullerene. As the group having a hetero ring, a group in which the hetero ring is a furan ring and / or a thiophene ring is preferable.

  A derivative of a heterocycle-containing fullerene can be obtained by a Diels-Alder reaction between a fullerene and a compound having a heterocycle such as a furan ring. Specifically, the reaction can be allowed to proceed by stirring the fullerene and a compound having a heterocycle such as furfuryl alcohol, furoyl chloride, carboxyl furan, and furfurylamine in a solvent in which both are dissolved. In this case, it is preferable to perform the reaction under a temperature condition of 30 to 100 ° C. using a compound having a fullerene and a heterocycle in an amount satisfying a fullerene / heterocycle molar ratio of fullerene / heterocycle <1.

  Heterocycle-containing fullerene derivatives may be used alone or in combination with other fullerene derivatives. In the present invention, the compatibility with other fullerene derivatives and compounds having a plurality of heterocycles in the molecule, and the solubility and dispersibility in the polymer constituting the solvent and liquid crystal aligning agent are excellent. Heterocycle-containing fullerene derivatives are preferred.

The fullerene compound (B) used in the present invention preferably contains fullerene C ₆₀ and / or fullerene C ₇₀ or a derivative thereof, and more preferably contains fullerene C ₆₀ and / or fullerene C ₇₀ .

The fullerene compound (B) used in the present invention preferably contains a fullerene mixture in which the total of fullerene C ₆₀ and fullerene C ₇₀ is 50 to 90% by weight based on the total amount of the fullerene compound (B). Crude fullerene in which the total of fullerene C ₆₀ and fullerene C ₇₀ is 50 to 90% by weight can be used. Such a crude fullerene can obtain the composition for forming an antireflection film according to the present invention at a lower cost than the case of using a high-purity purified fullerene or the like.

<Polymer>
The polymer contained in the composition for forming an antireflection film according to the present invention is a mixture of the compound (A-1) or (A-2) and the fullerene compound (B), preferably 40 to 200 ° C., preferably Can be produced by heating at a temperature in the range of 50 to 180 ° C.

  When the compound (A-1) is used as the compound having a vinyl group, the mixing molar ratio ((A-1) :( B)) of the compound (A-1) and the fullerene compound (B) is usually 1 : 99-99: 1, preferably 5: 95-95: 5, more preferably 10: 90-90: 10.

  When the compound (A-2) is used as the compound having a vinyl group, the mixing molar ratio ((A-2) :( B)) of the compound (A-2) and the fullerene compound (B) is usually 1 : 99-99: 1, preferably 5: 95-95: 5, more preferably 10: 90-90: 10.

  When the fullerene compound (B) is less than 1 mol%, an antireflection film having sufficient etching resistance cannot be obtained. When the fullerene compound (B) exceeds 99 mol%, the solubility of the polymer in the solvent decreases.

  As such a polymer, a polymer having a repeating unit (a-1) represented by the following formula (1) and a repeating unit (b) having a fullerene structure (hereinafter referred to as “polymer (I)”). And a polymer having a repeating unit (a-2) represented by the following formula (2) and a repeating unit (b) having a fullerene structure (hereinafter referred to as “polymer (II)”).

In the formula (1), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represent a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Show.

In the formula (2), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom or a monovalent group.

  The polymer may form a copolymer having the repeating unit (a-1) or (a-2) and the repeating unit (b), and the repeating unit (a-1) or (a-2) It is also possible to use a mixture of a polymer consisting of the above and a polymer consisting of the repeating unit (b).

Further, as the polymer, a polymer having a repeating unit (a-1) mixed with a fullerene compound (B) (hereinafter referred to as “polymer (III)”), a repeating unit (a-
2) and a polymer in which the fullerene compound (B) is mixed (hereinafter referred to as “polymer (IV)”).

  Among such polymers, a copolymer of the compound (A-1) or (A-2) and the fullerene compound (B) is preferable.

The weight average molecular weight (hereinafter referred to as “Mw”) measured by gel permeation chromatography of the polymer obtained from the compound (A-1) or (A-2) and the fullerene compound (B) is 3000 to 100 in terms of polystyrene. 1,000, preferably 3,000 to 20,000.

  The polymerization method is preferably solution polymerization, and the solvent used at this time is preferably an aromatic solvent such as benzene, toluene, ethylbenzene, anisole, chlorobenzene, dichlorobenzene, or trichlorobenzene. The polymerization initiator is not particularly limited, but an azo initiator, a peroxide initiator, or the like is used.

  In the present invention, one of the polymers (I) to (IV) may be used alone, but a blend of two or more of these polymers can also be used.

<Crosslinking agent (C)>
In addition to at least one polymer selected from the above polymers (I) to (IV), the composition for forming an antireflection film according to the present invention includes polynuclear phenols, azide compounds as a crosslinking agent (C), Or a commercially available hardening | curing agent can be used.

  Examples of polynuclear phenols include dinuclear phenols such as 4,4′-biphenyldiol, 4,4′-methylene bisphenol, 4,4′-ethylidene bisphenol, and bisphenol A; 4,4 ′, 4 ″ -methyl. Trinuclear phenols such as reddentrisphenol, 4,4 ′-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol; polyphenols such as novolak be able to.

  Of these polynuclear phenols, 4,4 '-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol, novolac and the like are preferable.

  As azide compounds, DZDS, BAP-P, DR-94Cl, DAzST (51), DAzST (4), DAzST (86), diazide chalcone, DAzST-Na, DAzBA (Na), BAC-H, BAC-M BAC-E (trade name, manufactured by Toyo Gosei Co., Ltd.) and the like can be used.

  Examples of the curing agent include 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 3,4-tolylene diisocyanate, 3,5-tolylene diisocyanate, and 4,4′-diphenylmethane diester. Diisocyanates such as isocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate; Epicoat 812, 815, 826, 828, 834, 836, 871, 1001, 1004 , 1007, 1009, 1031 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.), Araldite 6600, 6700, 6800, 502, 6071, 6084, 6097, 6099 (above) , Product name, manufactured by Ciba Geigy), DER331, 332, 333, 661, 644, 667 (trade name, manufactured by Dow Chemical Co., Ltd.) and the like; Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712, Melamine-based curing agents such as 701, 272, 202, My Coat 506, 508 (above, trade name, manufactured by Mitsui Cyanamid Co., Ltd.); Cymel 1123, 1123-10, 1128, My Coat 102, Benzoguanamine-based curing agents such as 105, 106 and 130 (trade names, manufactured by Mitsui Cyanamid Co., Ltd.); Cymel 1170, 1172 (trade names, manufactured by Mitsui Cyanamid Co., Ltd.), Nicarak N- And glycoluril-based curing agents such as 2702 (trade name, manufactured by Sanwa Chemical Co., Ltd.).

  These crosslinking agents (C) can be used individually by 1 type or in mixture of 2 or more types. The amount of the crosslinking agent (C) is usually 20 parts by weight or less, preferably 10 parts by weight or less per 100 parts by weight of the solid content of the composition for forming an antireflection film.

<Acid generator (D)>
The composition for forming an antireflection film according to the present invention may further contain an acid generator (D) that generates an acid by exposure or heating.

(Photoacid generator)
Examples of acid generators that generate acid upon exposure (hereinafter referred to as “photoacid generators”) include onium salt photoacid generators, halogen-containing compound photoacid generators, and diazoketone compound photoacid generators. Agents, sulfone compound photoacid generators, and sulfonic acid compound photoacid generators.

Examples of onium salt photoacid generators include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodoniumpyrenesulfonate, diphenyliodonium-n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium. Naphthalenesulfonate, diphenyliodonium hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-tert-butylphenyl) ) Iodonium n-dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodoni 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium naphthalenesulfonate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butane Sulfonate, triphenylsulfonium-n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium hexafluoroantimonate, 4-hydroxyphenyl phenylmethylsulfonium-p-toluenesulfonate, 4 -Hydroxyphenyl benzyl methylsulfonium-p-toluenesulfonate,
Cyclohexylmethyl 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldicyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate 4-cyano-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldiethylsulfonium trifluoro Lome Sulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldiethyl Sulfonium trifluoromethanesulfonate,
1- (4-hydroxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- [4- (1-methoxyethoxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-methoxyethoxy) naphthalene 1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothio Phenium trifluoromethanesulfonate, 1- (4-n-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate,
1- (4-i-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1 -(4-t-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-tetrahydrofuranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1 -[4- (2-tetrahydropyranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-benzyloxy) tetrahydrothiophenium trifluoro Tan sulfonate, 1- (such as naphthyl acetamide methyl) tetrahydrothiophenium trifluoromethanesulfonate, and the like.

  Examples of halogen-containing compound-based photoacid generators include phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine, and the like. Can be mentioned.

  Examples of the diazoketone compound photoacid generators include 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,3,4 of 4,4'-tetrahydroxybenzophenone, Examples thereof include 2-naphthoquinonediazide-4-sulfonic acid ester and 1,2-naphthoquinonediazide-5-sulfonic acid ester.

  Examples of the sulfone compound photoacid generators include 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, and the like.

  Examples of sulfonic acid compound photoacid generators include benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1]. ] Hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate, and the like.

  Among these photoacid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium-n-dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylpheny ) Such as iodonium naphthalene sulfonate is preferred.

The said photo-acid generator can be used individually by 1 type or in mixture of 2 or more types. When the photoacid generator is used, the exposure amount is usually 1 to 200 mJ / cm ² , preferably 10 to 1.
00 mJ / cm ² .

(Thermal acid generator)
Examples of the acid generator that generates an acid upon heating (hereinafter referred to as “thermal acid generator”) include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl. Examples thereof include sulfonates.

  These thermal acid generators can be used singly or in combination of two or more.

  The thermal acid generator is more preferably used than the photoacid generator because it generates an acid during firing to promote a crosslinking reaction. When using a thermal acid generator, the heating conditions are appropriately determined depending on the type of thermal acid generator used, but the heating temperature is usually 150 to 400 ° C., preferably 200 to 350 ° C., and the heating time is Usually 1 to 10 minutes, preferably 1 to 3 minutes.

  Moreover, in this invention, a photo-acid generator and a thermal acid generator can also be used together as an acid generator (D).

  The amount of the acid generator (D) is usually 5,000 parts by weight or less, preferably 0.1 to 1,000 parts by weight, more preferably 0, per 100 parts by weight of the solid content of the composition for forming an antireflection film. .1 to 100 parts by weight.

  By containing the acid generator (D), the antireflection film-forming composition according to the present invention can effectively form a crosslinked structure between the molecular chains of the polymer at a relatively low temperature including normal temperature. .

<Solvent (E)>
The composition for forming an antireflection film according to the present invention preferably contains a solvent (E). The solvent (E) used at this time is not particularly limited as long as it can dissolve the polymer and other components described later.

For example, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether;
Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate;
Diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether;
Triethylene glycol dialkyl ethers such as triethylene glycol dimethyl ether and triethylene glycol diethyl ether;
Propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether;
Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol di-n-butyl ether;
Propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoether ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate;
Lactic acid esters such as methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate, n-butyl lactate, i-butyl lactate;
Methyl formate, ethyl formate, n-propyl formate, i-propyl formate, n-butyl formate, i-butyl formate, n-amyl formate, i-amyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-acetate Propyl, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n propionate Aliphatic carboxylic esters such as butyl, i-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, i-butyl butyrate;
Ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate , Ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxypropyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3 -Other esters such as methyl-3-methoxybutyl butyrate, methyl acetoacetate, methyl pyruvate, ethyl pyruvate;
Aromatic hydrocarbons such as toluene and xylene;
Ketones such as methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone;
Amides such as N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone;
A lactone such as γ-butyrolactone is appropriately selected and used.

  Of these solvents, ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone and the like are preferably used. The said solvent can be used individually by 1 type or in mixture of 2 or more types.

  In the solvent (E), the solid content concentration of the composition for forming an antireflection film is usually 0.01 to 70% by weight, preferably 0.05 to 60% by weight, more preferably 0.1 to 50% by weight. Used in range quantities.

<Other ingredients>
In the composition for forming an antireflection film according to the present invention, (F) a binder resin, (G) a radiation absorber, (H) a surfactant, etc., as necessary, within a range not impairing the effects of the present invention. These various additives can be blended. In addition, additives such as a storage stabilizer, an antifoaming agent and an adhesion aid can be blended.

(F) Binder resin As binder resin (F), various thermoplastic and thermosetting synthetic resins other than the said polymer can be used.

Examples of thermoplastic resins include polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-heptene, poly-1-octene, poly-1-decene, poly- Α-olefin polymers such as 1-dodecene, poly-1-tetradecene, poly-1-hexadecene, poly-1-octadecene, polyvinylcycloalkane;
Α, β-unsaturated aldehyde polymers such as poly-1,4-pentadiene, poly-1,4-hexadiene, poly-1,5-hexadiene, poly-1,7-o-chloroacrolein; polymethylvinyl Α, β-unsaturated ketone polymers such as ketones, polyaromatic vinyl ketones and polycyclic vinyl ketones;
Polymers of α, β-unsaturated acid derivatives such as poly (meth) acrylic acid, salts of poly (meth) acrylic acid, esters of poly (meth) acrylic acid, halides of poly (meth) acrylic acid;
Polymers of α, β-unsaturated acid anhydrides such as poly (meth) acrylic anhydride, polymaleic anhydride;
Unsaturated polybasic acid ester polymers such as polymethylenemalonic acid diester and polyitaconic acid diester;
Diolefinic acid ester polymers such as polysorbic acid ester and muconic acid ester;
Α, β-unsaturated acid thioester polymers such as polyacrylic acid thioester, methacrylic acid thioester, α-chloroacrylic acid thioester;
Polymers of acrylonitrile derivatives such as polyacrylonitrile and polymethacrylonitrile;
Polymers of acrylamide derivatives such as polyacrylamide and polymethacrylamide;
Styryl metal compound polymers; polyvinyloxy metal compounds; polyimines;
Polyethers such as polyphenylene oxide, poly-1,3-dioxolane, polyoxirane, polytetrahydrofuran, polytetrahydropyran;
Polysulfides; polysulfonamides; polypeptides;
Polyamides such as nylon 66 and nylon 1 to nylon 12;
Polyesters such as aliphatic polyester, aromatic polyester, alicyclic polyester, polycarbonate, alkyd resin;
Polyureas; polysulfones; polyazines; polyamines; polyaromatic ketones;
Polyimides; polybenzimidazoles; polybenzoxazoles;
Polybenzothiazoles; polyaminotriazoles; polyoxadiazoles;
Polypyrazoles; polytetrazoles; polyquinoxalines; polytriazines;
Polybenzoxazinones; polyquinolines; polyanthrazolins and the like. These thermoplastic resins can be used individually by 1 type or in mixture of 2 or more types.

  As the binder resin (F), in addition to such a thermoplastic resin, in order to prevent intermixing with a resist, the composition is applied to a substrate and then cured by heating to become insoluble in a solvent. A thermosetting resin is also preferably used.

  Examples of such thermosetting resins include thermosetting acrylic resins, phenol resins, urea resins, melamine resins, amino resins, aromatic hydrocarbon resins, epoxy resins, alkyd resins, and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  The blending amount of these binder resins (F) is usually 20 parts by weight or less, preferably 10 parts by weight or less per 100 parts by weight of the polymer.

(G) Radiation absorber As a radiation absorber (G), the compound which has various radiation absorptivity can be used.

For example, oil-soluble dyes, disperse dyes, basic dyes, methine dyes, pyrazole dyes, imidazole dyes, hydroxyazo dyes and the like; bixin derivatives, norbixin, stilbene, 4,4'-diaminostilbene derivatives, coumarins Derivatives, pyrazoline derivatives and other brightening agents; hydroxyazo dyes, tinuvin 234 (trade name, manufactured by Ciba Geigy)
UV absorbers such as Tinuvin 1130 (trade name, manufactured by Ciba Geigy); aromatic compounds such as anthracene derivatives and anthraquinone derivatives.

  These radiation absorbers can be used alone or in combination of two or more. The blending amount of the radiation absorber (G) is usually 100 parts by weight or less, preferably 50 parts by weight or less, per 100 parts by weight of the solid content of the composition for forming an antireflection film.

(H) Surfactant In the present invention, a surfactant (H) may be added to the composition for forming an antireflection film in order to improve coatability, striation, wettability, developability and the like.

  Examples of the surfactant (H) include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol diester. Nonionic surfactants such as stearate can be mentioned.

  Further, KP341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) which is an organosiloxane polymer, Polyflow No. which is a (meth) acrylic acid-based (co) polymer. 75, no. 95 (above, trade name, manufactured by Kyoeisha Yushi Chemical Co., Ltd.), EFTOP EF101, EF204, EF303, EF352 (above, tradename, manufactured by Tochem Products), MegaFuck F171, F172, F173 (above, (Trade name, manufactured by Dainippon Ink & Chemicals, Inc.), FLORARD FC430, FC431, FC135, FC135 (above, product name, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S382, SC101, SC102, SC103, Commercially available surfactants such as SC104, SC105, and SC106 (above, trade name, manufactured by Asahi Glass Co., Ltd.) can also be used.

  These surfactants can be used singly or in combination of two or more. The compounding amount of the surfactant (H) is usually 15 parts by weight or less, preferably 10 parts by weight or less per 100 parts by weight of the solid content of the composition for forming an antireflection film.

[Antireflection film]
The antireflection film according to the present invention is, for example, a method comprising the following steps (I) to (V) using the above antireflection film forming composition (hereinafter also referred to as “the composition according to the present invention”). Can be manufactured.

<Method for producing and using antireflection film>
The method for producing an antireflection film according to the present invention usually comprises:
(I) a step of applying the composition according to the present invention on a substrate and curing the obtained coating film to form an antireflection film;
(II) applying a solution resist composition on the antireflection film, and prebaking the obtained coating film to form a resist film;
(III) a step of selectively exposing the resist film through a photomask;
(IV) a step of developing the exposed resist film, and (V) a step of etching the antireflection film.

(I) Antireflection film forming step:
First, the composition according to the present invention is applied onto a substrate by a known method such as spin coating, cast coating, or roll coating. As the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used.

  Next, the applied composition (coating film) is cured by exposure and / or heating. When curing the coating film by exposure, the radiation to be irradiated is from visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, gamma ray, molecular beam, ion beam, etc., depending on the type of photoacid generator used. It is selected appropriately. When a composition containing a photoacid generator is used and the coating film is cured by exposure, the coating film can be effectively cured even at room temperature. When the coating film is cured by heating, the heating temperature is usually about 90 to 350 ° C, preferably about 150 to 350 ° C.

  The film thickness of the antireflection film thus formed is usually 0.1 to 5 μm.

(II) Resist film formation process:
A resist composition in the form of a solution is applied onto the antireflection film formed in step (I) so that the resulting resist film has a predetermined thickness. By using the antireflection film according to the present invention, a resist film can be formed without causing intermixing.

  Examples of the resist composition include a positive or negative chemically amplified resist composition containing a photoacid generator, a positive resist composition comprising an alkali-soluble resin and a quinonediazide-based photosensitizer, and an alkali-soluble composition. Examples thereof include a negative resist composition comprising a resin and a crosslinking agent, and a silicon-containing resist composition. Among these, a silicon-containing resist composition is preferable in order to improve etching selectivity in the antireflection film etching step (V). Such a resist composition is applied in the form of a solution, and its solid content concentration is usually about 5 to 50% by weight. Such a resist composition in the form of a solution is usually used for forming a resist film after being filtered through a filter having a pore size of about 0.2 μm, for example. Moreover, a commercially available solution-form resist composition can also be used as it is.

  After applying the resist composition as described above, a resist film is formed by pre-baking and volatilizing the solvent in the film. The pre-baking temperature is appropriately adjusted according to the type of resist composition to be used, but is usually about 30 to 200 ° C, preferably 50 to 150 ° C.

(III) Exposure process:
The resist film formed in the step (II) is exposed through a photomask. At this time, the irradiated radiation is reflected on the substrate surface, but the radiation reflected from the substrate is absorbed by the action of the antireflection film according to the present invention.

The radiation used for exposure is appropriate from visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ-rays, molecular beams, ion beams, etc., depending on the type of photoacid generator used in the resist composition. Selected. Of these, preferred is far-ultraviolet, and in particular, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (wavelength 157 nm), Kr ₂ excimer laser (wavelength 147 nm), ArKr excimer laser (wavelength 134 nm), extreme ultraviolet light (wavelength 13 nm, etc.) and the like are preferable.

(IV) Development process:
The resist film exposed in the step (III) is developed, washed, and dried to form a predetermined resist pattern. In order to improve resolution, pattern profile, developability, etc., post-baking may be performed before development after exposure.

The developer is appropriately selected according to the type of resist composition used. Examples of the developer used in the case of a positive chemically amplified resist composition or a positive resist composition containing an alkali-soluble resin include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, and metasilicic acid. Sodium, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline , 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene, and the like. An appropriate amount of a water-soluble organic solvent, for example, an alcohol such as methanol or ethanol, or a surfactant can be added to these alkaline aqueous solutions.

(V) Etching process:
Using the resist pattern obtained in step (IV) as a mask, dry etching of the antireflection film is performed using, for example, gas plasma such as oxygen plasma to form a resist pattern for processing a predetermined substrate.

  Since the antireflection film according to the present invention is excellent in resistance to this dry etching, a resist pattern excellent in resolution and accuracy can be formed.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example. “Parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified. First, the evaluation method used in this example will be described.

<Evaluation method>
(Molecular weight measurement)
The weight average molecular weight (Mw) of the obtained polymer was a Tosoh GPC column (G2000HXL: 2, G3000HXL: 1), flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column temperature: 40. The measurement was performed by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under analysis conditions of ° C.

(Optical characteristics measurement)
An antireflection film-forming composition was spin-coated on an 8-inch silicon wafer, and then baked on a hot plate at 300 ° C. for 120 seconds to form an antireflection film having a thickness of 0.3 μm. The refractive index (n value) and absorbance (k value) at 248 nm were measured using a spectroscopic ellipsometer UV-1280E manufactured by KLA-TENCOR. Moreover, the n value and k value in 193 nm were measured using the spectroscopic ellipsometer MOSS-ESVG DEEP UV by SOPRA.

[Synthesis Example 1]
(Synthesis of polymer of compound (A-1) and fullerene compound)
In a separable flask equipped with a thermometer, 1 part of 4-hydroxymethylstyrene, 8 parts of fullerene C ₆₀ , 86.5 parts of toluene, and 4. 4 parts of azobisisobutyronitrile were added under a nitrogen atmosphere. 3 parts was charged and polymerized at 80 ° C. for 24 hours with stirring. Thereafter, the reaction solution was filtered with filter paper, the filtrate was concentrated, and the obtained solid was redissolved in 2-heptanone. The insoluble material was filtered again with filter paper, and the filtrate was reprecipitated in a large amount of hexane, filtered and dried to obtain a polymer (1) having an Mw of 3,000.

[Synthesis Example 2]
(Synthesis of polymer of compound (A-2) and fullerene compound)
In a separable flask equipped with a thermometer, under a nitrogen atmosphere, 3.8 parts of acenaphthylene, 1 part of fullerene C ₆₀ , 80 parts of toluene, and 6.4 parts of azobisisobutyronitrile. The polymerization was carried out at 90 ° C. for 12 hours while charging and stirring. Thereafter, the reaction solution was filtered with filter paper, the filtrate was concentrated, and the obtained solid was redissolved in 2-heptanone. Insoluble matter was filtered again with filter paper, and the filtrate was reprecipitated in a large amount of hexane, filtered and dried to obtain a polymer (2) having an Mw of 3,000.

[Preparation Example 1]
(Preparation of resist solution for ArF)
In a separable flask equipped with a reflux tube, 8-methyl-8-t-butoxycarbonylmethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] Dodeka
29 parts 3-ene, 8-hydroxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] Dodeka
3-ene 10 parts, maleic anhydride 18 parts, 2,5-dimethyl-2,5-hexanediol diacrylate 4 parts, t-dodecyl mercaptan 1 part, azobisisobutyronitrile 4 parts and 1,2-di 60 parts of ethoxyethane was charged and polymerized at 70 ° C. for 6 hours. After completion of the polymerization, the reaction solution was poured into a large amount of n-hexane / i-propyl alcohol (weight ratio = 1/1) mixed solution to solidify the resin. The coagulated resin was washed several times with the same mixed solvent and then vacuum dried to obtain a copolymer. The yield of this copolymer was 60%, and Mw was 27,000. Further, in this copolymer, the contents of the structural units represented by the following formulas (a), (b) and (c) were 64 mol%, 18 mol% and 18 mol%, respectively.

(1) Preparation of composition for formation of antireflection film 10 parts of polymer (1) prepared in Synthesis Example 1, Cymel 300 (Mitsui Cyanamid Co., Ltd.)
0.5 part) and 0.5 part of bis (4-t-butylphenyl) iodonium camphorsulfonate were dissolved in 89 parts of 2-heptanone. The obtained solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare an antireflection film-forming composition.

(2) Formation of antireflection film The composition obtained in (1) above was spin-coated on an 8-inch silicon wafer so as to obtain an antireflection film having a film thickness of 0.3 μm, and then on a hot plate. An antireflection film was formed by baking at 300 ° C. for 120 seconds.

(3) Formation of positive resist pattern for KrF On the antireflection film obtained in (2) above, a KrF resist solution (trade name: KRF M20G, manufactured by JSR Corporation) with a film thickness of 0.31 μm After spin coating to obtain a resist film, the resist film was baked on a hot plate at 140 ° C. for 1 minute to form a resist film.

  Next, using a stepper NSR2005EX12B (wavelength 248 nm, manufactured by Nikon Corporation), an exposure time for forming a line-and-space pattern having a width of 0.22 μm with a one-to-one line width (hereinafter referred to as “optimum exposure time”) .) Only exposed. Then, after baking for 90 seconds on a 140 ° C. hot plate, using a 2.38% tetramethylammonium hydroxide aqueous solution, developed at 23 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. Formed.

(4) Formation of KrF positive resist pattern On the antireflection film obtained in the above (2), an ArF resist solution was spin-coated so as to obtain a 0.2 μm-thick resist film, and then hot plate The resist film was formed by baking at 100 ° C. for 90 seconds.

  Next, exposure was performed through a mask pattern by an ArF excimer laser exposure apparatus (lens numerical aperture 0.60, exposure wavelength 193 nm, manufactured by ISI). Then, after baking at 140 ° C. for 90 seconds on a hot plate, using a 2.38% tetramethylammonium hydroxide aqueous solution, developed at 25 ° C. for 1 minute, washed with water, and dried to form a positive resist pattern. did.

(5) Measurement of optical characteristics About the antireflection film obtained in (2) above, a refractive index (n value) and absorbance (k value) at 248 nm using a spectroscopic ellipsometer UV-1280E (manufactured by KLA-TENCOR). Was measured. Moreover, n value and k value in 193 nm were measured using the spectroscopic ellipsometer MOSS-ESVG DEEP UV (made by SOPRA).

(6) Evaluation of anti-intermixing effect For each of the resist patterns formed in the above (3) and (4), the degree of tailing of the resist film at the contact point between the portion remaining after development and the antireflection film It investigated using the microscope.

(7) Evaluation of Standing Wave Prevention Effect For each of the resist patterns formed in the above (3) and (4), the presence of the influence of the standing wave on the resist pattern (backlash of the side wall of the resist pattern) is determined by scanning electron. It investigated using the microscope.

(8) Evaluation of etching resistance The antireflection film obtained in (2) above was subjected to CF ₄ / Ar / O ₂ (CF ₄ : 40 mL / min, Ar: 20 mL) using an etching apparatus EXAM (manufactured by Shinko Seiki) / Min, O ₂ : 5 mL / min; pressure: 20 Pa; RF power: 200 W; treatment time: 40 seconds; temperature: 15 ° C.), the film thickness before and after the treatment was measured, and the etching rate was calculated. .

  The results of evaluating the obtained antireflection film and resist pattern are shown in Table 1.

  10 parts of the polymer (2) prepared in Synthesis Example 2 was used instead of the polymer (1) prepared in Synthesis Example 1, and BAC-E (manufactured by Toyo Gosei Co., Ltd.) was used instead of Cymel 300. Prepared an antireflection film-forming composition in the same manner as in Example 1. Using this composition for forming an antireflection film, an antireflection film and a resist film (resist pattern) were formed in the same manner as in Example 1, and these were evaluated. The results are shown in Table 1.

[Comparative Example 1]
Resist patterns were prepared and evaluated in the same manner as in Example 1 except that a resist film was formed on a silicon wafer without forming an antireflection film. The results are shown in Table 1.

[Comparative Example 2]
An antireflection film and a resist pattern were formed in the same manner as in Example 1 except that novolak resin was used instead of the composition for forming an antireflection film, and these were evaluated. The results are shown in Table 1.

  The composition for forming an antireflection film according to the present invention is excellent in dry etching resistance, has a high antireflection effect, and can form an antireflection film that does not cause intermixing with a resist. It is particularly useful for manufacturing.

Claims (6)

An antireflection film-forming composition comprising a polymer having a repeating unit (a-1) represented by the following formula (1) and a repeating unit (b) having a fullerene structure.

(In Formula (1), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represent a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Indicates) An antireflective film-forming composition comprising a polymer having a repeating unit (a-2) represented by the following formula (2) and a repeating unit (b) having a fullerene structure.

(In Formula (2), R ⁵ , R ⁶ and R ⁷ each independently represents a hydrogen atom, a halogen atom or a monovalent group) Selected from the group consisting of at least one compound (A-1) represented by the following formula (3) or at least one compound (A-2) represented by the following formula (4), fullerene and a fullerene derivative An antireflective film-forming composition comprising a polymer obtained by mixing at least one fullerene compound (B) and heating in the presence of a radical initiator.

(In Formula (3), R ¹ represents a hydrogen atom or a fluorine atom, R ² and R ³ each independently represents a hydrogen atom, a fluorine atom or a monovalent group, and R ⁴ represents a halogen atom or a monovalent group. Indicates)

(In the formula (4), R ⁵ , R ⁶ and R ⁷ each independently represents a hydrogen atom, a halogen atom or a monovalent group)   The composition for forming an antireflection film according to any one of claims 1 to 3, further comprising a crosslinking agent (C).   The composition for forming an antireflection film according to any one of claims 1 to 4, further comprising an acid generator (D).   The antireflection film formed by heating the coating film formed using the composition in any one of Claims 1-5 at 150-350 degreeC.