JP4433933B2 - Radiation-sensitive composition and hard mask forming material - Google Patents

Description

  The present invention contains a copolymer having an acrylic ester-based repeating unit having an epoxy group in the side chain and an acenaphthylene-based repeating unit and a radiation-sensitive acid generator, and forms a crosslinked structure by irradiation with radiation. A radiation-sensitive composition in which a later cross-linked coating can be easily peeled off from a substrate, and a hardware suitable for microfabrication by a lithography process using various types of radiation, particularly for manufacturing highly integrated circuit elements, containing the radiation-sensitive composition The present invention relates to a mask forming material.

A wide variety of cross-linkable polymers that have become insoluble in solvents by forming a cross-linked structure by heat treatment or radiation irradiation have been developed so far as image forming materials, stereolithography materials, curable adhesives, paints, etc. Although it is used in a wide range of fields, in the molecular design of these crosslinkable polymers, physical properties required for each application (thermal properties of crosslinked products, solvent resistance, alkali resistance, curing speed, photosensitive wavelength, etc.) , Etc.).
By the way, when forming a pattern by etching the underlying layer on the substrate by microfabrication by a lithography process, a pattern forming layer having an etching selectivity greatly different from that of the underlying layer is formed, and the underlying layer is etched using this as a mask. Although a method for forming a pattern on the underlayer has been proposed, a pattern forming layer having a significantly different etching selectivity from the underlayer is called a hard mask. By using this hard mask, a pattern is formed under the underlayer. There is an advantage that a pattern can be formed only on the base layer without damaging the substrate or the like positioned.
However, apart from the case where it is used as a permanent coating film, the method using this hard mask is often convenient if an operation for removing the crosslinked resin is necessary after use or if it can be removed after use. Is difficult to remove. That is, conventional methods for removing a hard mask formed on a substrate include a method of decomposing by a chemical reaction using a strong alkali or strong acid, an ashing method using oxygen plasma treatment, an organic solvent, There is a method of mechanically removing it by swelling, but with these methods, the processing environment is harsh and it is difficult to remove without damaging the substrate.

  On the other hand, Patent Document 1 discloses a homopolymer consisting of only a repeating unit contained in a repeating unit represented by the formula (1-1) described later, or the repeating unit and a (meth) acrylate ester unit, (meth) acrylamide. A photosensitive resin composition in which a copolymer having a system unit, an N-vinylpyrrolidone unit or a styrene unit is combined with a photoacid generator (that is, a radiation-sensitive acid generator) has photocrosslinkability, It is disclosed that it can be easily removed by heating at a relatively low temperature after crosslinking, and can be used for resists, adhesives, and the like. Photocrosslinkable copolymers are described. However, considering the removal, recovery and treatment after use, there is very little research on radiation-crosslinked resins or compositions that can easily decompose the crosslinked resin even under mild conditions. is there.

JP 2001-226430 A Chem. Mater., Vol.14, No.1, p.334-340 (2002) Chem. Mater., Vol.15, No.21, p.4075-4081 (2003)

  The object of the present invention is to overcome the above-mentioned conventional problems, form a crosslinked structure by irradiation with radiation, decompose by heating at a relatively low temperature after crosslinking, and reduce the molecular weight, without easily damaging the substrate. A radiation-sensitive composition useful for forming a hard mask that can be peeled, has a high standing wave prevention effect, does not cause intermixing with a resist film, and can form a resist pattern excellent in resolution, pattern shape, etc. Is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention obtained an acrylate-based repeating unit having an epoxy group in its ester portion and an acenaphthylene-based repeating unit having high absorbance to radiation such as an excimer laser. The film formed from the copolymer can effectively solve the above-mentioned problems as a hard mask. After processing the substrate, it is decomposed by heat treatment and / or radiation irradiation to reduce the molecular weight, and can be easily peeled off with an alkaline aqueous solution. It has been found that a hard mask superior in peelability compared to a conventional coating type hard mask can be obtained, and the present invention has been achieved.

The present invention, first,
(A) a copolymer having a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2), (B) a radiation sensitive acid generator, and (C) a solvent. It consists of a radiation sensitive composition characterized by containing.

〔一般式（１）において、Ｒ¹ は水素原子または１価の有機基（但し、エポキシ基を有するものを除く。）を示し、各Ｒ² は相互に独立に水素原子または１価の有機基（但し、エポキシ基を有するものを除く。）を示し、Ｒ³ はエポキシ基を有する１価の有機基を示す。〕

[In General Formula (1), R ¹ represents a hydrogen atom or a monovalent organic group (excluding those having an epoxy group), and each R ² independently represents a hydrogen atom or a monovalent organic group. (However, those having an epoxy group are excluded.), And R ³ represents a monovalent organic group having an epoxy group. ]

〔一般式（２）において、各Ｒ⁴ は相互に独立に水素原子または１価の有機基（但し、エポキシ基を有するものを除く。）を示す。〕

[In General Formula (2), each R ⁴ independently represents a hydrogen atom or a monovalent organic group (excluding those having an epoxy group). ]

The present invention secondly,
A hard mask forming material comprising the radiation-sensitive composition.

Hereinafter, the present invention will be described in detail.
Radiation sensitive composition -Copolymer [I]-
The component (A) in the radiation-sensitive composition of the present invention is represented by the repeating unit represented by the general formula (1) (hereinafter referred to as “repeating unit (1)”) and the general formula (2). And a repeating unit (hereinafter referred to as “repeating unit (2)”) (hereinafter referred to as “copolymer [I]”).

In the general formula (1), the monovalent organic group represented by R ¹ is preferably a group having 1 to 10 carbon atoms. Examples of preferable monovalent organic groups include a phenyl group, an alkyl group, an alkenyl group, and an acyl group. Or a phenyl group, an alkyl group or an alkenyl group as one of substituents such as a halogen atom, a hydroxyl group, an alkoxyl group, an acyloxy group, a phenoxy group, a vinyloxy group, a mercapto group, a carboxyl group, a nitro group, and a sulfonic acid group. Examples include groups substituted with one or more of the above.

As said alkyl group, a C1-C6 linear or branched alkyl group is preferable, More preferably, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i -Butyl group, sec-butyl group, t-butyl group and the like.
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 methallyl group, a 1-butenyl group, a 2-butenyl group, or the like. is there.
Moreover, as said acyl group, a C2-C6 aliphatic or aromatic acyl group is preferable, More preferably, they are an acetyl group, a propionyl group, a butyryl group, a benzoyl group etc.

In general formula (1), R ¹ is particularly preferably a hydrogen atom or a methyl group.

In addition, the monovalent organic group for R ² is preferably a group having 1 to 10 carbon atoms. Examples of the preferred monovalent organic group are the same as those exemplified for the preferred monovalent organic group for R ¹ . You can list things.

In general formula (1), each R ² is preferably a hydrogen atom, a methyl group, an ethyl group or the like, and particularly preferably a methyl group.

In the general formula (1), the monovalent organic group having an epoxy group of R ³ is preferably a group having 2 to 10 carbon atoms. Examples of the monovalent organic group having a preferable epoxy group include 1, 2 -Epoxyethyl group, glycidyl group, 2,3-epoxybutyl group, 3,4-epoxybutyl group, 3,4-epoxycyclopentyl group, 3,4-epoxy-3-methylcyclopentyl group, 3,4-epoxycyclohexyl Group, a 3,4-epoxy-3-methylcyclohexyl group, a 3,4-epoxy-4-methylcyclohexyl group, and the like, and a 3,4-epoxy-4-methylcyclohexyl group is particularly preferable.

  Specific examples of the particularly preferred repeating unit (1) in the present invention include a repeating unit represented by the following formula (1-1).

〔式（１−１）において、Ｒ⁵ は水素原子またはメチル基を示す。〕
共重合体〔Ｉ〕において、繰り返し単位（１）は、単独でまたは２種以上が存在することができる。

[In Formula (1-1), R ⁵ represents a hydrogen atom or a methyl group. ]
In the copolymer [I], the repeating unit (1) may be present alone or in combination of two or more.

In the general formula (2), the monovalent organic group for each R ⁴ is preferably a group having 1 to 10 carbon atoms, and a preferable monovalent organic group is preferably R ¹ in the general formula (1). The thing similar to the group illustrated about the monovalent organic group can be mentioned.
In general formula (2), each R ⁴ is particularly preferably a hydrogen atom.

As the repeating unit (2), for example,
Acenaphthylene;
3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1,3-dimethylacenaphthylene, 1,4-dimethylacenaphthylene, 1,5-dimethylacenaphthylene, 1, 6-dimethylacenaphthylene, 1,7-dimethylacenaphthylene, 1,8-dimethylacenaphthylene, 1,2,3-trimethylacenaphthylene, 1,2,4-trimethylacenaphthylene, 1,2 , 5-trimethylacenaphthylene, 1-phenyl-3-methylacenaphthylene, 1-phenyl-4-methylacenaphthylene, 1-phenyl-5-methylacenaphthylene, 1-phenyl-6-methylacenaphthylene 1-phenyl-7-methylacenaphthylene, 1-phenyl-8-methylacenaphthylene, 1,2-diphenyl-3-methylacenaphthylene 1,2-diphenyl-4-methyl-acenaphthylene, 1,2-diphenyl-5-methyl-substituted acenaphthylene such as methyl acenaphthylene;

3-hydroxymethylacenaphthylene, 4-hydroxymethylacenaphthylene, 5-hydroxymethylacenaphthylene, 1-methyl-3-hydroxymethylacenaphthylene, 1-methyl-4-hydroxymethylacenaphthylene, 1- Methyl-5-hydroxymethylacenaphthylene, 1-methyl-6-hydroxymethylacenaphthylene, 1-methyl-7-hydroxymethylacenaphthylene, 1-methyl-8-hydroxymethylacenaphthylene, 1,2- Dimethyl-3-hydroxymethylacenaphthylene, 1,2-dimethyl-4-hydroxymethylacenaphthylene, 1,2-dimethyl-5-hydroxymethylacenaphthylene, 1-phenyl-3-hydroxymethylacenaphthylene, 1-phenyl-4-hydroxymethylacenaphthylene, 1-phen 5-hydroxymethylacenaphthylene, 1-phenyl-6-hydroxymethylacenaphthylene, 1-phenyl-7-hydroxymethylacenaphthylene, 1-phenyl-8-hydroxymethylacenaphthylene, 1,2- Hydroxymethyl group-substituted acenaphthylenes such as diphenyl-3-hydroxymethylacenaphthylene, 1,2-diphenyl-4-hydroxymethylacenaphthylene, 1,2-diphenyl-5-hydroxymethylacenaphthylene;

3-methoxymethylacenaphthylene, 4-methoxymethylacenaphthylene, 5-methoxymethylacenaphthylene, 1-methyl-3-methoxymethylacenaphthylene, 1-methyl-4-methoxymethylacenaphthylene, 1- Methyl-5-methoxymethylacenaphthylene, 1-methyl-6-methoxymethylacenaphthylene, 1-methyl-7-methoxymethylacenaphthylene, 1-methyl-8-methoxymethylacenaphthylene, 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 aceto 1-phenyl-6-methoxymethyl acenaphthylene, 1-phenyl-7-methoxymethyl acenaphthylene, 1-phenyl-8-methoxymethyl acenaphthylene, 1,2-diphenyl-3-methoxymethyl acenaphthylene Methoxymethyl-substituted acenaphthylenes such as len, 1,2-diphenyl-4-methoxymethylacenaphthylene, 1,2-diphenyl-5-methoxymethylacenaphthylene, etc .:

3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene, 5-acetoxymethyl acenaphthylene, 1-methyl-3-acetoxymethyl acenaphthylene, 1-methyl-4-acetoxymethyl acenaphthylene, 1- Methyl-5-acetoxymethylacenaphthylene, 1-methyl-6-acetoxymethylacenaphthylene, 1-methyl-7-acetoxymethylacenaphthylene, 1-methyl-8-acetoxymethylacenaphthylene, 1,2- Dimethyl-3-acetoxymethyl acenaphthylene, 1,2-dimethyl-4-acetoxymethyl acenaphthylene, 1,2-dimethyl-5-acetoxymethyl acenaphthylene, 1-phenyl-3-acetoxymethyl acenaphthylene, 1-phenyl-4-acetoxymethylacenaphthylene, 1-phen 5-5-acetoxymethyl acenaphthylene, 1-phenyl-6-acetoxymethyl acenaphthylene, 1-phenyl-7-acetoxymethyl acenaphthylene, 1-phenyl-8-acetoxymethyl acenaphthylene, 1,2- Acetoxymethyl group-substituted acenaphthylenes such as diphenyl-3-acetoxymethylacenaphthylene, 1,2-diphenyl-4-acetoxymethylacenaphthylene, 1,2-diphenyl-5-acetoxymethylacenaphthylene,

3-phenoxymethyl acenaphthylene, 4-phenoxymethyl acenaphthylene, 5-phenoxymethyl acenaphthylene, 3-vinyloxymethyl acenaphthylene, 4-vinyloxymethyl acenaphthylene, 5-vinyloxymethyl acenaphthylene Examples thereof include a repeating unit in which a 1,2-unsaturated bond is cleaved.

  Among these repeating units (2), acenaphthylene, 3-hydroxymethyl acenaphthylene, 4-hydroxymethyl acenaphthylene, 5-hydroxymethyl acenaphthylene, 3-methoxymethyl acenaphthylene, 4-methoxymethyl acenaphthylene Preferred is a repeating unit in which a 1,2-unsaturated bond is cleaved, such as len, 5-methoxymethyl acenaphthylene, 3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene, 5-acetoxymethyl acenaphthylene, In particular, a repeating unit represented by the following formula (2-1) is preferable.

共重合体〔Ｉ〕において、繰り返し単位（２）は、単独でまたは２種以上が存在することができる。

In the copolymer [I], the repeating unit (2) may be present alone or in combination of two or more.

The copolymer [I] can have a repeating unit other than the repeating unit (1) and the repeating unit (2) (hereinafter referred to as “other repeating unit”).
Examples of other repeating units include:
4-hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl-1-vinylnaphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 2-hydroxymethyl-6-vinylnaphthalene, etc. Compound;
4-methoxymethyl-1-vinylnaphthalene, 7-methoxymethyl-1-vinylnaphthalene, 8-methoxymethyl-1-vinylnaphthalene, 4-methoxymethyl-1-isopropenylnaphthalene, 7-methoxymethyl-1-isopropenyl Methoxymethyl group / vinyl group substituted naphthalene compounds such as naphthalene and 8-methoxymethyl-1-isopropenylnaphthalene;
4-acetoxymethyl-1-vinylnaphthalene, 4-phenoxymethyl-1-vinylnaphthalene, 4-vinyloxymethyl-1-vinylnaphthalene, 4-acetoxymethyl-1-isopropenylnaphthalene, 4-phenoxymethyl-1-iso Other vinyl group-substituted naphthalene compounds such as propenylnaphthalene and 4-vinyloxymethyl-1-isopropenylnaphthalene;

Styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-hydroxymethylstyrene, 3-hydroxymethylstyrene, 4-hydroxymethylstyrene, 2-methoxymethylstyrene, 3-methoxymethyl Other aromatic vinyl compounds such as styrene, 4-methoxymethylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 9-vinylanthracene, 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, n-hexyl (meth) Unsaturated carboxylic acid ester compounds such as acrylate and glycidyl (meth) acrylate;

Unsaturated group-containing unsaturated carboxylic acid ester-based 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;
Carboxyl group-containing vinyl compounds such as succinic acid mono [2- (meth) acryloyloxyethyl], maleic acid mono [2- (meth) acryloyloxyethyl], phthalic acid mono [2- (meth) acryloyloxyethyl], etc. And a repeating unit in which the polymerizable unsaturated bond is cleaved.

Among these other repeating units, a repeating unit in which a polymerizable unsaturated bond is cleaved such as 2-hydroxymethyl-6-vinylnaphthalene, 4-hydroxymethylstyrene, 4-methoxymethylstyrene and the like is preferable.
In the copolymer [I], other repeating units may be present alone or in combination of two or more.

In the copolymer [I], the content of the repeating unit (1) is preferably 10 to 90 mol%, more preferably 20 to 80 mol%, particularly preferably 30 to 70 mol%, based on all repeating units. The content of the repeating unit (2) is preferably from 10 to 90 mol%, more preferably from 20 to 80 mol%, particularly preferably from 30 to 70 mol%, based on all repeating units. The content of repeating units is preferably 80 mol% or less, more preferably 50 mol% or less, based on all repeating units.
In this case, if the content of the repeating unit (1) is less than 10 mol%, it is difficult to sufficiently crosslink, and the effect of preventing intermixing at the time of resist coating tends to be reduced, whereas if it exceeds 90 mol%, the substrate There is a possibility that the mask performance (also referred to as etching resistance) at the time of processing may be impaired, or sufficient antireflection performance may not be obtained due to insufficient absorbance. On the other hand, if the content of the repeating unit (2) is less than 10 mol%, the mask performance during substrate processing may be impaired, or the absorbance may be insufficient, and sufficient antireflection performance may not be obtained. If it exceeds 1, it is difficult to sufficiently crosslink, and the effect of preventing intermixing at the time of resist coating tends to be reduced. Moreover, when the content rate of another repeating unit exceeds 80 mol%, there exists a tendency for peeling performance to fall.

  The polystyrene-converted weight average molecular weight (hereinafter referred to as “Mw”) of the copolymer [I] measured by gel permeation chromatography is preferably 500 to 10,000.

  The copolymer [I] is, for example, a polymerizability that gives an acrylic ester monomer corresponding to the repeating unit (1) and an acenaphthylene corresponding to the repeating unit (2), optionally giving another repeating unit. Along with the unsaturated compound, it can be produced by polymerization in an appropriate polymerization form such as bulk polymerization or solution polymerization by radical polymerization, anionic polymerization, cationic polymerization or the like.

  The copolymer [I] has a property of forming a crosslinked structure by irradiation and being decomposed by heat treatment and / or irradiation to reduce the molecular weight, and is particularly useful for forming a coating type hard mask. In addition to being able to be used very suitably as a component of radiation-sensitive compositions, it can be used alone, or mixed with other curable resins and curable rubbers, to form paints, adhesives, insulating materials, stereolithography materials, and moldings. It can also be used for goods.

-Radiosensitive acid generator-
The component (B) in the radiation-sensitive composition of the present invention is a radiation-sensitive material that generates an acid upon irradiation with radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray (hereinafter referred to as “exposure”). It consists of an acid generator.

As such a radiation sensitive acid generator, for example,
Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodoniumpyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodoniumnaphthalenesulfonate Diphenyliodonium hexafluoroantimonate,
Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, Bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium naphthalenesulfonate, bis (4-t- Butylphenyl) iodonium hexafluoroantimonate,

Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10-camphor Sulfonate, triphenylsulfonium hexafluoroantimonate,
4-hydroxyphenyl phenyl methylsulfonium p-toluenesulfonate, 4-hydroxyphenyl benzyl methylsulfonium p-toluenesulfonate,
Cyclohexyl methyl 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 trifluoromethanesulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy- 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4 Hydroxy-1-naphthyl diethyl sulfonium trifluoromethane sulfonate,

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) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate,

1- (4-n-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-i-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, (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] te La hydro thiophenium trifluoromethanesulfonate,
Onium salt compounds such as 1- (4-benzyloxy) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate;

Halogen-containing compounds such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine;
1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2, naphthoquinonediazide-4-sulfonic acid ester of 2,3,4,4′-tetrahydroxybenzophenone or Diazo ketone compounds such as 1,2-naphthoquinonediazide-5-sulfonic acid ester;
Sulfone compounds such as 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane;
Benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1] hept-5-ene-2,3-di Examples thereof include sulfonic acid compounds such as carbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate.

Among these radiation-sensitive acid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalene Sulfonate, 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) iodonium 10-camphorsulfonate, bis (4-t-butyl) Eniru) such iodonium naphthalene sulfonate is preferred.
The said radiation sensitive acid generator can be used individually or in mixture of 2 or more types.

The radiation-sensitive composition of the present invention can effectively form a crosslinked structure between the molecular chains of the copolymer [I] at a relatively low temperature including normal temperature by containing a radiation-sensitive acid generator. It becomes.
The amount of the radiation-sensitive acid generator is usually 50 parts by weight or less, preferably 0.1 to 30 parts by weight, more preferably 0.1 to 15 parts by weight per 100 parts by weight of the solid content of the radiation-sensitive composition. Part.

-Solvent-
As the solvent which is the component (C) in the radiation-sensitive composition of the present invention, the copolymer [I], the radiation-sensitive acid generator and the additive component described later can be dissolved, and have an appropriate volatility. As long as it has, it is not particularly limited, 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 acid 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;
Examples include lactones such as γ-butyrolactone.

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 preferable.
The said solvent can be used individually or in mixture of 2 or more types.

  The amount of the solvent used is such that the solid content concentration of the radiation-sensitive composition is usually 0.01 to 70% by weight, preferably 0.05 to 60% by weight, more preferably 0.1 to 50% by weight. It is.

-Additives-
In the radiation-sensitive composition of the present invention, various kinds of agents such as a cross-linking agent, a thermal acid generator, a binder resin, a radiation absorber, and a surfactant are used as necessary as long as the intended effect in the present invention is not impaired. Additives can be blended.

The crosslinking agent, for example, more effectively prevents intermixing between a hard mask film obtained from a radiation-sensitive composition and a resist film formed thereon, and also prevents cracks in the hard mask. It is a component having
As such a crosslinking agent, polynuclear phenols and various commercially available curing agents can be used.
Examples of the polynuclear phenols include binuclear phenols such as 4,4′-biphenyldiol, 4,4′-methylene bisphenol, 4,4′-ethylidene bisphenol, and bisphenol A; 4,4 ′, 4 ″. -Trinuclear phenols such as methylidenetrisphenol, 4,4 '-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol; polyphenols such as novolak Can be mentioned.
Among these polynuclear phenols, 4,4 ′-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol and novolak are preferable.
The polynuclear phenols can be used alone or in admixture of two or more.

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 ′. -Diisocyanates such as diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, and the following trade names: Epicoat 812, 815, 826, 828, 834, 834 871, 1001, 1004, 1007, 1007, 1009, 1031 (Oilized Shell Epoxy), Araldite 6600, 6700, 6800, 502, 6071, 6084, 6097, 6099 (above, manufactured by Ciba Geigy), DER331, 332, 333, 66 1, epoxy compound such as 644, 667 (manufactured by Dow Chemical Co.); Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712, Melting agents such as 701, 272, 202, My Coat 506, 508 (above, manufactured by Mitsui Cyanamid Co., Ltd.); Cymel 1123, 1123-10, 1128, My Coat 102, 105, Benzoguanamine type curing agents such as 106, 130 (above, Mitsui Cyanamid Co., Ltd.), etc .; Cymel 1170, 1172 (above, Mitsui Cyanamid Co., Ltd.), Nicarak N-2702 (Sanwa Chemical Co., Ltd.) ) And the like.
Of these curing agents, melamine curing agents, glycoluril curing agents and the like are preferable. The said hardening | curing agent can be used individually or in mixture of 2 or more types.
Moreover, polynuclear phenols and a hardening | curing agent can also be used together as a crosslinking agent.

  The amount of the crosslinking agent is usually 50 parts by weight or less, preferably 30 parts by weight or less per 100 parts by weight of the solid content of the radiation-sensitive composition.

Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl sulfonates.
These thermal acid generators can be used alone or in admixture of two or more.

As the binder resin, various thermoplastic resins and thermosetting resins can be used.
As the thermoplastic resin, for example,
Polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-heptene, poly-1-octene, poly-1-decene, poly-1-dodecene, poly-1- Α-Olefin polymers such as tetradecene, poly-1-hexadecene, poly-1-octadecene, and polyvinylcycloalkane; poly-1,4-pentadiene, poly-1,4-hexadiene, poly-1,5-hexadiene Non-conjugated diene polymers such as
α, β-unsaturated aldehyde polymers; α, β-unsaturated ketone polymers such as poly (methyl vinyl ketone), poly (aromatic vinyl ketone), poly (cyclic vinyl ketone); (meth) acrylic acid Polymers of α, β-unsaturated carboxylic acids or derivatives thereof such as, α-chloroacrylic acid, (meth) acrylate, (meth) acrylic acid ester, (meth) acrylic acid halide; Polymers of α, β-unsaturated carboxylic acid anhydrides such as copolymers of acrylic acid anhydride and maleic anhydride; Polymers of unsaturated polybasic carboxylic acid esters such as methylenemalonic acid diester and itaconic acid diester Kind;

Polymers of diolefin carboxylic acid esters such as sorbic acid ester and muconic acid ester; Polymers of α, β-unsaturated carboxylic acid thioesters such as (meth) acrylic acid thioester and α-chloroacrylic acid thioester; ) Polymers of (meth) acrylonitrile such as acrylonitrile and α-chloroacrylonitrile or derivatives thereof; Polymers of (meth) acrylamide or derivatives thereof such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide; Polymers of metal compounds; Polymers of vinyloxy metal compounds;
Polyimines; polyethers such as polyphenylene oxide, poly-1,3-dioxolane, polyoxirane, polytetrahydrofuran, polytetrahydropyran; polysulfides; polysulfonamides; polypeptides; nylon 66, nylon 1 to nylon 12, etc. Polyamides; Polyesters such as aliphatic polyesters, aromatic polyesters, alicyclic polyesters and polycarbonates; Polyureas; Polysulfones; Polyazines; Polyamines; Polyaromatic ketones; Polyimides; Polybenzoxazoles; polybenzothiazoles; polyaminotriazoles; polyoxadiazoles; polypyrazoles; polytetrazoles; polyquinoxalines; polytriazines; Down like; quinoline compounds; mention may be made of a poly-Anne tiger gelsolin, and the like.

In addition, the thermosetting resin is cured by heating and becomes insoluble in a solvent, and the intermixing between the hard mask film obtained from the radiation-sensitive composition and the resist film formed thereon is further effectively performed. It is a component having an action to prevent, and can be preferably used as a binder resin.
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.
Of these thermosetting resins, urea resins, melamine resins, aromatic hydrocarbon resins and the like are preferable.
The said binder resin can be used individually or in mixture of 2 or more types.
The blending amount of the binder resin is usually 20 parts by weight or less, preferably 10 parts by weight or less per 100 parts by weight of the copolymer [I].

Examples of the radiation absorber include oil-soluble dyes, disperse dyes, basic dyes, methine dyes, pyrazole dyes, imidazole dyes, hydroxyazo dyes, and the like; bixin derivatives, norbixine, stilbene, Fluorescent brighteners such as 4,4′-diaminostilbene derivatives, coumarin derivatives, pyrazoline derivatives; hydroxyazo dyes, tinuvin 234 (trade name, manufactured by Ciba Geigy), tinuvin 1130 (trade name, manufactured by Ciba Geigy), etc. Ultraviolet absorbers; aromatic compounds such as anthracene derivatives and anthraquinone derivatives.
These radiation absorbers can be used alone or in admixture of two or more.
The blending amount of the radiation absorber 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 radiation-sensitive composition.

The surfactant is a component having an effect of improving coatability, striation, wettability, developability and the like.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene-n-octylphenyl ether, polyoxyethylene-n-nonylphenyl ether, and polyethylene. Nonionic surfactants such as glycol dilaurate and polyethylene glycol distearate, and KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Yushi Chemical Co., Ltd.), Ftop EF101, EF204, EF303, EF352 (above, manufactured by Tochem Products), MegaFuck F171, F172, F173 (above, Dainippon) Ink Chemical Industry Co., Ltd.), Florard FC430, FC431, FC135, FC135, FC93 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.) and the like.
These surfactants can be used alone or in admixture of two or more.
The compounding amount of the surfactant 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 radiation-sensitive composition.
Furthermore, examples of additives other than those described above include storage stabilizers, antifoaming agents, and adhesion aids.

  The radiation-sensitive composition of the present invention can be used particularly suitably as a hard mask forming material to be described later, and can also be used for paints, adhesives, insulating materials, stereolithographic materials, molded articles, and the like. it can.

Hard mask forming material The hard mask forming material of the present invention contains the radiation-sensitive composition.
As a utilization form of the hard mask formed from the hard mask formation material of this invention, what includes the process of following 1) -7) can be mentioned, for example.
1) A step of applying a hard mask forming material on a substrate and curing the obtained coating film to form a hard mask coating;
2) A step of applying a resist composition on the hard mask film and pre-baking the obtained coating film to form a resist film;
3) a step of selectively exposing the resist film through a photomask;
4) developing the exposed resist film to form a resist pattern;
5) forming a hard mask by etching the hard mask film;
6) A step of processing the substrate through the formed hard mask, and 7) A step of heat-treating and / or exposing the hard mask and then treating the substrate with an alkaline aqueous solution to peel off the hard mask from the substrate.

Hereinafter, this usage pattern will be described more specifically.
In step 1), for example, a silicon wafer, a wafer coated with aluminum, or the like can be used as the substrate.
The hard mask forming material can be applied by an appropriate method such as spin coating, cast coating or roll coating.
Then, after heating the coating film, it is further exposed to form a crosslinked structure between the molecular chains of the copolymer [I] in the coating film, thereby curing the coating film and forming a hard mask film. .
The radiation to be exposed may be appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, γ-ray, molecular beam, ion beam, etc., depending on the type of radiation-sensitive acid generator used. However, when light energy is used, light having a wavelength in the range of 157 to 365 nm, preferably in the range of 157 to 248 nm is suitable.
The exposure amount is usually about 5 to 100 J / m ² , preferably about 10 to 50 J / m ² .
The hard mask forming material of the present invention can effectively form a crosslinked structure even at room temperature by such exposure, but may be subjected to heat treatment during and / or after exposure.
The heating temperature during the heat treatment before exposure and at the time of exposure and / or heat treatment after the exposure is usually about 90 to 350 ° C., preferably about 200 to 300 ° C., but the radiation sensitive composition generates thermal acid. When an agent is contained, for example, a relatively low temperature of about 90 to 150 ° C. is sufficient.
1) The film thickness of the hard mask film formed in the step is usually 0.1 to 5 μm, preferably 0.1 to 2.0 μm.

Next, in step 2), the resist composition is applied as a solution on the hard mask film so that the resulting resist film has a predetermined thickness, and then prebaked to form a resist film.
The prebaking temperature at this time is appropriately adjusted according to the type of the resist composition to be used, and is usually about 30 to 200 ° C, preferably 50 to 150 ° C.
Examples of the resist composition include a positive or negative chemically amplified resist composition containing a radiation sensitive acid 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 composed of a resin and a crosslinking agent.
The solid content concentration of the resist composition as a solution is usually about 5 to 50% by weight. In general, the resist composition is filtered through a filter having a pore diameter of about 0.2 μm and provided for forming a resist film. In this step, a commercially available resist composition solution can be used as it is.

Next, in step 3), the radiation used for exposure is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, gamma rays, molecular beams, ion beams, etc., depending on the type of resist composition. Preferably, it is far ultraviolet rays, 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.
The exposure amount is appropriately selected according to the type of resist composition, the size of the intended resist pattern, and the like.

Next, in step 4), the resist film after exposure is developed, washed, and dried to form a resist pattern. In this step, post-baking can be performed after exposure and before development in order to improve resolution, pattern shape, developability, and the like.
The developer used in this step is appropriately selected according to the type of resist composition used, but development in the case of a positive chemically amplified resist composition or a positive resist composition containing an alkali-soluble resin. Examples of the liquid include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethyl / ethanol. Amine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3. 0] -5-none Aqueous solution of an alkaline compounds such can be mentioned. In addition, 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 the aqueous solution of these alkaline compounds.

  Next, in step 5), the resist pattern is removed by performing dry etching of the hard mask film using, for example, gas plasma such as oxygen plasma, using the formed resist pattern as a mask, and a hard mask having a predetermined shape is obtained. Form.

  Next, in step 6), using the obtained hard mask as a mask, a predetermined pattern is formed on the substrate by performing dry etching using gas plasma such as CF4 / O2 / Ar.

Next, in step 7), the hard mask is subjected to heat treatment and / or exposure to decompose the copolymer [I] in the hard mask to lower the molecular weight, and then the substrate is treated with an alkaline aqueous solution or the like. The hard mask can be removed without damaging the substrate.
The treatment conditions in the heat treatment are usually about 100 to 300 ° C. for about 1 to 10 minutes, preferably about 100 to 200 ° C. for about 1 to 3 minutes.
The radiation used for the exposure can be appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, electron beams, γ rays, molecular beams, ion beams, etc., preferably ultraviolet rays, far ultraviolet rays. It is.
The exposure amount is usually about 5 to 100 mJ / m ² , preferably about 10 to 50 mJ / m ² . However, in the case where the heat treatment and exposure are combined, it is possible to lower the heating temperature, shorten the heating time, or reduce the exposure amount.
Although it does not specifically limit as aqueous alkali solution used at this process, The thing similar to the aqueous solution of the alkaline compound quoted at the said 4) process can be used, The density | concentration is 1-90 normally. Normal, preferably 1 to 4 normal.
Further, when removing the hard mask, it may be treated with pure water, an organic solvent or the like in addition to the alkaline aqueous solution. As the latter organic solvent, for example, those exemplified as the component (C) in the radiation-sensitive composition of the present invention can be used.

The radiation-sensitive composition of the present invention can be used particularly suitably as a main component of the hard mask forming material of the present invention.
The hard mask formed from the hard mask forming material of the present invention has excellent releasability, and the hard mask can be easily processed without damaging the substrate by performing heat treatment and / or exposure to the hard mask after processing the substrate. Can be peeled off. In addition, the hard mask has a high effect of preventing standing waves and does not cause intermixing with the resist film. Therefore, in cooperation with various positive and negative resist compositions, the resolution and pattern shape It is possible to provide an excellent resist pattern. Further, the hard mask has good dry etching resistance because the copolymer [I] as the main component has an acenaphthylene-based repeating unit.
Therefore, the radiation-sensitive composition and hard mask forming material of the present invention largely contributes to the production of highly integrated circuits.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following, “part” is based on weight unless otherwise specified.
Mw of the resin obtained in the following Preparation Example 1 and the copolymer [I] obtained in Synthesis Example 1 uses a GPC column (G2000HXL: 2 pieces, G3000HXL: 1 piece) manufactured by Tosoh Corporation. Measurement was carried out by detecting with a differential refractometer by gel permeation chromatography using monodisperse polystyrene as a standard under the analysis conditions of 0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C.

The performance evaluation of the hard mask was performed as follows.
Hard mask film formation:
A hard mask forming material was spin-coated on a silicon wafer having a diameter of 8 inches, and then heated on a hot plate at 345 ° C. for 120 seconds to form a hard mask film having a thickness of 0.1 μm.

Formation of positive resist pattern by KrF excimer laser:
A hard mask forming material was spin-coated on a silicon wafer having a diameter of 8 inches, and then heated on a hot plate at 345 ° C. for 120 seconds to form a hard mask film having a thickness of 0.6 μm. Thereafter, a resist composition for KrF excimer laser (trade name: KRFM20G, manufactured by JSR Corporation) is spin-coated on this hard mask film, prebaked on a hot plate at 140 ° C. for 60 seconds, and a film thickness of 0.61 μm. The resist film was formed. Then, using a Nikon stepper NSR2005EX12B (wavelength of 248 nm), an exposure time for forming a line-and-space pattern with a line width of 0.22 μm with a KrF excimer laser through the mask pattern with a one-to-one line width ( Hereinafter, only the “optimum exposure time” was exposed). Then, after post-baking on a hot plate at 140 ° C. for 90 seconds, using a 2.38 wt% tetramethylammonium hydroxide aqueous solution, developing at 23 ° C. for 30 seconds, washing with water and drying, a positive resist pattern is formed. Formed.

Formation of positive resist pattern by ArF excimer laser:
A hard mask material was spin-coated on a silicone wafer having a diameter of 8 inches and then baked on a hot plate at 345 ° C. for 120 seconds to form a hard mask film having a thickness of 0.6 μm. Thereafter, the ArF excimer laser resist composition obtained in Preparation Example 1 described later is spin-coated on this hard mask film, and pre-baked on a 130 ° C. hot plate for 90 seconds to form a 0.5 μm-thick resist film. Formed. Thereafter, using an ArF excimer laser exposure apparatus (lens numerical aperture 0.60, exposure wavelength 193 nm) manufactured by ISI, exposure was performed for an optimal exposure time through a mask pattern. Then, after post-baking on a hot plate at 130 ° C. for 90 seconds, using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, developing at 25 ° C. for 1 minute, washing with water and drying, a positive resist A pattern was formed.

Evaluation of peelability:
When the hard mask film formed as described above is heated at 200 ° C. for 2 minutes and then exposed to a 2.38% by weight tetramethylammonium hydroxide aqueous solution, the case where the hard mask film can be completely peeled is indicated with “◯”. The case where a residual film was observed when the hard mask film was peeled off was evaluated as “x”.

Evaluation of standing wave prevention effect:
A positive resist pattern was formed as described above, and observed with a scanning electron microscope, and the presence or absence of a standing wave preventing effect on the resist film was evaluated.

Evaluation of the effect of preventing intermixing:
The hard mask film formed as described above was immersed in propylene glycol monomethyl ether acetate for 1 minute at room temperature, and the change in film thickness before and after immersion was measured using a spectroscopic ellipsometer UV-1280E manufactured by KLA-TENCOR. A case where no change in film thickness was observed was evaluated as “◯”, and a case where a film thickness change was observed was evaluated as “x”.

Preparation Example 1 (Preparation of resist composition for ArF excimer laser)
In a separable flask equipped with a reflux tube, 8-methyl-8-t-butoxycarbonylmethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] 29 parts dodec-3-ene, 8-methyl-8-hydroxytetracyclo [4.4.0.1 ^2,5 .
[1 ^7,10 ] 10 parts dodec-3-ene, 18 parts maleic anhydride, 4 parts 2,5-dimethyl-2,5-hexanediol diacrylate, 1 part t-dodecyl mercaptan, 4 azobisisobutyronitrile And 60 parts of 1,2-diethoxyethane were charged and polymerized at 70 ° C. for 6 hours with stirring. Thereafter, the reaction solution is poured into a large amount of a mixed solvent of n-hexane / i-propyl alcohol (weight ratio = 1/1) to solidify the resin, and the solidified resin is washed several times with the mixed solvent, and then vacuumed. After drying, the content of each repeating unit represented by the following formula (a), formula (b) or formula (c) is 64 mol%, 18 mol% and 18 mol%, respectively, and Mw is 27,000. Of 60% by weight was obtained.

  Next, 80 parts of the obtained resin, 1.5 parts of 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate and 0.04 part of tri-n-octylamine were added to propylene glycol. An ArF excimer laser resist composition was prepared by dissolving in 533 parts of monomethyl ether acetate.

Synthesis Example 1 (Synthesis of copolymer [I])
In a separable flask equipped with a thermometer, in a nitrogen atmosphere, 4 parts of methacrylic acid α-terpineol epoxide ester (corresponding to the repeating unit in which R ⁵ is a methyl group in the formula (1-1)), ⁵ parts of acenaphthylene, 50 parts of n-butyl acetate and 4 parts of azobisisobutyronitrile were charged and polymerized at 80 ° C. for 7 hours with stirring. Thereafter, the reaction solution was diluted with 100 parts of n-butyl acetate, and the organic layer was washed with a large amount of a mixed solvent of water / methanol (weight ratio = 1/2), and then the solvent was distilled off to obtain an Mw of 1,000. The copolymer [I] was obtained at a yield of 80% by weight.

Example 1 (Evaluation of hard mask forming material)
10 parts of the copolymer [I] obtained in Synthesis Example 1, 0.5 part of bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, and 4,4 ′-[1- {4- (1- [4 -Hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol 0.5 part is dissolved in 89 parts of ethyl lactate, and the solution is filtered through a membrane filter having a pore size of 0.1 μm to prepare a hard mask forming material. did.
Next, using this hard mask forming material, a positive resist pattern was formed using a KrF excimer laser or an ArF excimer laser in the manner described above, and performance evaluation was performed. The evaluation results are shown in Table 1.

Example 2 (Evaluation of hard mask forming material)
10 parts of the copolymer [I] obtained in Synthesis Example 1, 0.5 parts of bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate and 4,4 ′-[1- {4- (1 -[4-Hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol 0.5 part was dissolved in 89 parts ethyl lactate, and the solution was filtered through a membrane filter having a pore size of 0.1 μm to form a hard mask. The material was prepared.
Next, using this hard mask forming material, a positive resist pattern was formed using a KrF excimer laser or an ArF excimer laser in the manner described above, and performance evaluation was performed. The evaluation results are shown in Table 1.

Comparative Example 1
A positive resist pattern was formed using a KrF excimer laser or an ArF excimer laser in the same manner as described above except that no hard mask forming material was used, and performance evaluation was performed. The evaluation results are shown in Table 1.

Comparative Example 2
Instead of the hard mask coating obtained from the hard mask forming material of the present invention, a lower antireflection film B200 (trade name) manufactured by JSR Corporation is formed on a silicone wafer having a diameter of 8 inches and heat-treated at 200 ° C. for 2 minutes. Thereafter, the film was exposed to an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38% by weight to evaluate the peelability. Further, the same procedure as described above was performed except that a lower antireflection film B200 was formed on a silicon wafer having a diameter of 8 inches instead of the hard mask film obtained from the hard mask forming material of the present invention by the above-described procedure. A positive resist pattern was formed using a KrF excimer laser or an ArF excimer laser, and the performance was evaluated. The evaluation results are shown in Table 1.

Claims (5)

(A) a copolymer having a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2), (B) a radiation sensitive acid generator, and (C) a solvent. A radiation-sensitive composition characterized by comprising.

[In General Formula (1), R ¹ represents a hydrogen atom or a monovalent organic group (excluding those having an epoxy group), and each R ² independently represents a hydrogen atom or a monovalent organic group. (However, those having an epoxy group are excluded.), And R ³ represents a monovalent organic group having an epoxy group. ]

[In General Formula (2), each R ⁴ independently represents a hydrogen atom or a monovalent organic group (excluding those having an epoxy group). ] The radiation-sensitive composition according to claim 1, wherein the repeating unit represented by the general formula (1) according to claim 1 is a repeating unit represented by the following formula (1-1).

[In Formula (1-1), R ⁵ represents a hydrogen atom or a methyl group. ] The radiation-sensitive composition according to claim 1 or 2, wherein the repeating unit represented by the general formula (2) according to claim 1 is a repeating unit represented by the following formula (2-1). .

  Furthermore, the radiation sensitive composition in any one of Claims 1-3 containing a crosslinking agent.   A hard mask forming material comprising the radiation-sensitive composition according to claim 1.