KR20130035940A - Composition for forming resist lower layer film, resist lower layer film and method for forming the same, and method for forming pattern - Google Patents

Abstract

PURPOSE: A composition for forming a resist underlayer is provided to maintain high refraction resistance of a resist underlayer and to form a resist underlayer with high heat resistance. CONSTITUTION: A composition for forming a resist underlayer contains a polymer which has a structure unit represented by chemical formula 1: -(C=C-Ar^1-C=C-Ar^2)-. In chemical formula 1, each of Ar^1 and Ar^2 is a divalent group represented by chemical formula 2: -R^1-(R^3-R^2)a-. In chemical formula 2, each of R^1 and R^2 is a divalent aromatic group; R^2 is a single bond, -O-, -CO-, -SO-, or -SO2-; a is an integer from 0-3; and when a is 2 or more, R^2 and R^3 can be the same or different from each other.

Description

A composition for forming a resist underlayer film, a resist underlayer film, a method for forming the same, and a method for forming a pattern TECHNICAL FIELD OF THE INVENTION, AND METHOD FOR FORMING PATTERN TECHNOLOGY FOR FORMING RESIST LOWER LAYER

The present invention relates to a composition for forming a resist underlayer film, a resist underlayer film, a method for forming the same, and a pattern forming method.

In the manufacture of integrated circuit devices, multilayer resist processes are used today to achieve higher densities. Briefly describing this process, first, a composition for forming a resist underlayer film is applied onto a substrate to form a resist underlayer film, and then a photoresist composition is applied thereon to form a resist film, followed by a reduction projection exposure apparatus (stepper). The mask pattern is transferred to the resist film by using a film or the like, and developed with a suitable developer to obtain a resist pattern. Thereafter, this resist pattern is transferred to a resist underlayer film by dry etching. Finally, by transferring the resist underlayer film pattern to the substrate by dry etching, a substrate having a desired pattern can be obtained.

In the above-mentioned multilayer resist process, further refinement | miniaturization of the formed pattern is made, and therefore the said resist underlayer film is calculated | required further improvement of pattern transfer performance and etching resistance. In response to such a request, various studies have been made on structures such as polymers contained in the composition for forming a resist underlayer film and functional groups contained therein (see Japanese Patent Laid-Open No. 2004-177668).

On the other hand, with the miniaturization of the formed pattern, RIE (Reactive Ion Etching) is prevalent as the dry etching method, and therefore, when the substrate is etched using the resist underlayer film as a mask, the resist underlayer film pattern is bent, The problem that deformation | transformation, such as becoming a wavy form, arises is remarkable.

In addition, although the organic composition is conventionally used in the formation of a resist underlayer film in the point which does not require a special apparatus for its formation, in the resist underlayer film using this organic composition, there exists a difficulty in heat resistance, and is due to the low heat resistance, By heating at the time of forming a resist underlayer film, etc., a resist underlayer film component may sublimate, and this sublimation component may reattach to a board | substrate, and may worsen the manufacturing yield of a semiconductor device.

In such a situation, at the time of further miniaturization of the pattern, a resist having high heat resistance while satisfying the characteristics related to the refractive index and the attenuation coefficient required for the resist underlayer film while maintaining high bending resistance of the formed resist underlayer film pattern The development of the resist underlayer film forming composition which can form an underlayer film is desired.

Japanese Patent Laid-Open No. 2004-177668

The present invention has been made on the basis of the above circumstances, and its object is to satisfy the characteristics related to the refractive index and the attenuation coefficient required for the resist underlayer film, and to maintain a high bending resistance of the formed resist underlayer film pattern. It is providing the composition for resist underlayer film formation which can form the resist underlayer film which has heat resistance.

The invention made to solve the above problems,

[A] A composition for forming a resist underlayer film containing a polymer having a structural unit (I) represented by the following general formula (1) (hereinafter also referred to as "[A] polymer").

(In Formula (1), Ar ¹ And Ar ² are each independently a divalent group represented by the following general formula (2)):

(Formula (2) of, R ¹ and R ² are each independently an aromatic divalent group, R ³ represents a single bond, -O-, -CO-, -SO- or -SO ₂ - and, a is from 0 to An integer of 3, provided that when a is 2 or more, a plurality of R ² and R ³ may be the same or different, respectively)

Since the composition for resist underlayer film formation of this invention contains the [A] polymer which has the said specific structural unit (I), the said composition for resist underlayer film formation maintains high bending resistance of the resist underlayer film pattern formed, A resist underlayer film having high heat resistance can be formed.

It is preferable that R <^1> and R <^2> in the said General formula (2) are respectively independently represented by following General formula (3).

Of (formula (3), R ⁴ is a hydroxyalkyl group of a halogen atom, a hydroxy group, a cyano group, a nitro group, a C 1 -C 20 monovalent hydrocarbon group, an alkoxy group or a group having 1 to 20 carbon atoms having from 1 to 20, b Is an integer of 0 to 6, provided that when b is 2 or more, a plurality of R ⁴ may be the same or different, and c is 0 or 1)

The R ¹ And since R <^2> is the said specific group, the said composition for resist underlayer film formation can form the resist underlayer film which has higher heat resistance.

It is preferable that the polystyrene conversion weight average molecular weight of the polymer (A) is 500 or more and 10,000 or less. When the polystyrene reduced weight average molecular weight of the polymer [A] is within the above specific range, the composition for forming a resist underlayer film can improve applicability.

It is preferable that the said composition for resist underlayer film formation further contains a solvent [B]. When the composition for forming a resist underlayer film further contains the solvent [B], the composition for forming a resist underlayer film can further improve applicability.

It is preferable that the said composition for resist underlayer film formation contains [C] acid generator further. When the composition for forming a resist underlayer film further contains an [C] acid generator, the composition for forming a resist underlayer film can harden a resist underlayer film efficiently and can suppress intermixing of a resist underlayer film and a resist film.

It is preferable that the said composition for resist underlayer film formation further contains a crosslinking agent [D]. The composition for forming a resist underlayer film further contains a crosslinking agent [D], whereby the composition for forming a resist underlayer film is bonded by forming a crosslinkable group of the [A] polymer and another crosslinking agent molecule. The resist underlayer film used can be hardened more.

The formation method of the resist underlayer film of this invention is

(1-1) forming a coating film on a substrate using the composition for forming a resist underlayer film, and

(1-2) Process of forming a resist underlayer film by heating the said coating film

Respectively.

Since the formation method of the said resist underlayer film has the said specific process, the formation method of the said resist underlayer film can form the resist underlayer film which has high heat resistance.

The resist underlayer film of this invention is formed from the said composition for resist underlayer film formation.

Since the resist underlayer film is formed of the composition for forming a resist underlayer film, the resist underlayer film has high heat resistance.

The pattern forming method of the present invention comprises:

(1) forming a resist underlayer film on a substrate using the composition for forming a resist underlayer film,

(2) forming a resist film on the resist underlayer film using a resist composition;

(3) forming a resist pattern from the resist film, and

(4) A step of forming a predetermined pattern on the substrate by dry-etching the resist underlayer film and the substrate sequentially using the resist pattern as a mask.

In the pattern forming method, since the resist underlayer film is formed using the composition for forming a resist underlayer film, the pattern forming method can increase the heat resistance of the resist underlayer film while maintaining high bending resistance of the formed resist underlayer film pattern. As a result, the pattern forming method can form a more refined pattern.

The resist composition is a photoresist composition,

The step (3),

(3-1) exposing the resist film by selective radiation; and

(3-2) Process of developing the exposed said resist film

It is preferable to include.

Since the said resist composition is a photoresist composition and the said process (3) includes the said process, the said pattern formation method can form a finer pattern simply and surely.

In addition, the polystyrene conversion weight average molecular weight (Mw) of polymer [A] means what was measured by the gel permeation chromatography (detector: differential refractometer) which makes monodisperse polystyrene the standard.

According to the composition for forming a resist underlayer film, the resist underlayer film, the method for forming the same, and the pattern forming method of the present invention, the resist underlayer film pattern formed while satisfying the characteristics of the refractive index and the attenuation coefficient required for the resist underlayer film The heat resistance of the resist underlayer film can be improved while maintaining high bending resistance. Therefore, according to this invention, the manufacturing yield of a semiconductor device can be improved in a semiconductor manufacturing process, and it can be used suitably for the manufacturing process of the semiconductor device which further refines a pattern.

<Composition for forming a resist underlayer film>

The composition for forming a resist underlayer film of this invention contains a polymer [A]. The resist underlayer film-forming composition may further contain a solvent [B], an acid generator [C], and a crosslinking agent [D] as a suitable component. Moreover, the said composition for resist underlayer film formation may contain other arbitrary components in the range which does not impair the effect of this invention. Hereinafter, each component will be described in detail.

<[A] Polymer>

The polymer (A) is a polymer having the structural unit (I) represented by the general formula (1). In addition, the polymer [A] may have other structural units. In addition, a polymer [A] may also contain 2 or more types of each structural unit.

[Structural unit (I)]

Structural unit (I) is a structural unit represented by the said General formula (1). When the composition for forming a resist underlayer film of the present invention contains the polymer [A] having the specific structural unit (I), the composition for forming a resist underlayer film is high while maintaining high bending resistance of the formed resist underlayer film pattern. A resist underlayer film having heat resistance can be formed.

In Formula (1), Ar ¹ And Ar ² are each independently a divalent group represented by the formula (2).

In said Formula (2), R <^1> and R <^2> is a bivalent aromatic group each independently. R ³ is a single bond, -O-, -CO-, -SO- or -SO _2- . a is an integer of 0-3. However, when a is two or more, some R <^2> and R <^3> may be same or different, respectively.

As a bivalent aromatic group represented by said R <^1> and R <^2> , a C6-C30 bivalent aromatic hydrocarbon group and a C3-C30 bivalent heteroaromatic group are mentioned.

As said C6-C30 bivalent aromatic hydrocarbon group, a phenylene group, a naphthylene group, anthranilene group etc. are mentioned, for example.

As said C3-C30 bivalent heteroaromatic group, the bivalent group containing a pyrrole ring, a pyridine ring, an indole ring, a quinoline ring, an acridine ring, etc. are mentioned, for example.

The hydrogen atom which the said divalent aromatic hydrocarbon group and the divalent hetero aromatic group have may be substituted by the substituent. As this substituent, group represented by R <^{4> mentioned} later, for example is applicable.

The structural unit (I) is, for example, the aromatic ring of the divalent aromatic hydrocarbon group and the heterocyclic heteroaromatic group, such as the 1,4 position of the benzene ring, the 2,6 position of the naphthalene ring, the 2,6 position of the anthracene ring, and the like. The molecular structure to which the polymer main chain does not couple | bond to the site | part opposing in an aromatic ring is preferable, and this molecular structure is especially preferable when said R <^3> is a single bond. By doing in this way, the solubility to a solvent can be improved.

It is preferable that R <^1> and R <^2> in the said General formula (2) are respectively independently represented by the said General formula (3). When said R <^1> and R <^2> is the said specific group, the said composition for resist underlayer film formation can form the resist underlayer film which has a much higher heat resistance.

In said general formula (3), R <^4> is a halogen atom, a hydroxyl group, a cyano group, a nitro group, a C1-C20 monovalent hydrocarbon group, a C1-C20 alkoxy group, or a C1-C20 hydroxyalkyl group. b is an integer of 0-6. However, when b is two or more, some R <^4> may be same or different. c is 0 or 1;

As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, for example.

As a C1-C20 monovalent hydrocarbon group represented by said R <^4> , For example, a C1-C20 alkyl group, a C3-C20 monovalent alicyclic hydrocarbon group, or the monovalent group which combined 2 or more types of these groups Etc. can be mentioned.

As said C1-C20 alkyl group, For example, linear alkyl groups, such as a methyl group, an ethyl group, n-propyl group, n-butyl group; Branched alkyl groups, such as i-propyl group, i-butyl group, sec-butyl group, and t-butyl group, etc. are mentioned.

As said C3-C20 monovalent alicyclic hydrocarbon group, For example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, methylcyclohexyl group, Monocyclic saturated hydrocarbon groups such as ethylcyclohexyl group; Monocyclic unsaturated hydrocarbons, such as a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a cyclo octenyl group, a cyclodecenyl group, a cyclopentadienyl group, a cyclohexadienyl group, a cyclooctadienyl group, and a cyclodecadiene group; Bicyclo [2.2.1] heptyl group, Bicyclo [2.2.2] octyl group, Tricyclo [5.2.1.0 ^2,6 ] decyl group, ^Tricyclo [3.3.1.1 ^3,7 ] decyl group, Tetracyclo [6.2 .1.1 ^3,6 .0 ^2,7 ] polycyclic saturated hydrocarbon groups such as dodecyl group, norbornyl group and adamantyl group.

As a monovalent group which combined 2 or more types of these groups, the group which combined 2 or more types of groups illustrated as said C1-C20 alkyl group and C3-C20 monovalent alicyclic hydrocarbon group etc. are mentioned, for example. .

As a C1-C20 alkoxy group represented by said R <^4> , a methoxy group, an ethoxy group, a propoxy group, isopropoxy group, butoxy group, isobutoxy group, t-butoxy group, etc. are mentioned, for example.

As a C1-C20 hydroxyalkyl group represented by said R <^4> , For example, a hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3 -Hydroxypropyl group, 1-hydroxy-1-methylethyl group, 2-hydroxy-1-methylethyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, etc. are mentioned. have.

In formula (3), b is preferably 0, and c is preferably 0.

As the structural unit (I), a structural unit represented by the following chemical formula is preferable.

In the polymer (A), the content ratio of the structural unit (I) to the total structural units is preferably 50 mol% or more and 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less. By making the content rate of a structural unit (I) into the said specific range, heat resistance can be raised effectively and bending resistance can be improved.

[Other structural units]

The polymer (A) may have a structural unit other than the structural unit (I) within a range that does not impair the effects of the present invention.

<Method of synthesizing [A] polymer>

As the method for synthesizing the polymer (A), for example, a compound (monomer) corresponding to a predetermined structural unit can be dissolved in a suitable reaction solvent and synthesized by performing a condensation polymerization reaction in the presence of a catalyst and a basic compound.

Examples of the catalyst include palladium compounds such as bis (triphenylphosphine) dichloropalladium and bis (triphenylphosphine) dibromopalladium, copper chloride (I), copper bromide (I), and copper iodide (I). The combination with monovalent copper compounds, such as these, etc. are mentioned. These catalysts can use together 1 type (s) or 2 or more types.

Examples of the basic compound include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethyl monoethanolamine and monomethyl diethanolamine. , Triethanolamine, diazabicyclooctane, and the like. These basic compounds can use together 1 type (s) or 2 or more types.

It will not specifically limit, if it is solvent other than the solvent which inhibits a condensation polymerization reaction as a reaction solvent. As a reaction solvent, For example, halogen solvents, such as chloroform, dichloromethane, 1,2-dichloroethane, chlorobenzene, dichlorobenzene; Aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene and diethylbenzene; Ether solvents such as diethyl ether, tetrahydrofuran, dioxane, diglyme and anisole; Ketone solvents such as acetone, methyl ethyl ketone, 2-heptanone, cyclohexanone and cyclopentanone; Ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; Amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone.

It is preferable to collect | recover the [A] polymer obtained by condensation polymerization reaction by the reprecipitation method. That is, the target [A] polymer is collect | recovered by throwing in the reaction liquid after completion | finish of condensation polymerization reaction. As a reprecipitation solvent, alcohol, alkanes, etc. can use together 1 type (s) or 2 or more types. In addition to the reprecipitation method, the low molecular weight component may be removed and the polymer [A] may be recovered by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

The reaction temperature in these synthesis methods is suitably determined by the compound (monomer) which provides a structural unit (I), the kind of catalyst used, a basic compound, etc.

As polystyrene conversion weight average molecular weight (Mw) by gel permeation chromatography (GPC) of the polymer (A), 500 or more and 10,000 or less are preferable, and 1,000 or more and 5,000 or less are more preferable. By making Mw of a polymer into the said specific range, the said composition for resist underlayer film formation can improve the in-plane uniformity of a resist underlayer film.

<[B] solvent>

The solvent (B) is a suitable component which the composition for forming a resist underlayer film may contain. The solvent (B) is not particularly limited as long as it can dissolve or disperse the polymer [A] and optional components contained as necessary. When the composition for forming a resist underlayer film further contains the solvent [B], the composition for forming a resist underlayer film can further improve applicability. Examples of the solvent (B) include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and the like. Moreover, [B] solvent can use together 1 type (s) or 2 or more types.

As the alcohol solvent, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, t-butanol, n-pentanol, iso-pentanol, sec-pentane Monoalcohol solvents such as ol and t-pentanol; Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, etc. And polyhydric alcohol solvents.

Examples of the ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, and ethyl-n. Aliphatic ketone solvents such as -butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone, and trimethylnonanone; Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone; 2,4-pentanedione, acetonyl acetone, diacetone alcohol, acetophenone, etc. are mentioned.

Examples of the amide solvents include N, N'-dimethylimidazolidinone, N-methyl formamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, and N-methyl acetate Amide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like.

As said ether solvent, For example, Alkyl ether of polyhydric alcohols, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether; Alkyl ether acetates of polyhydric alcohols such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and propylene glycol methyl ether acetate; Aliphatic ethers such as diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether and diisoamyl ether; Aliphatic-aromatic ethers such as anisole and phenylethyl ether; Cyclic ethers, such as tetrahydrofuran, tetrahydropyran, and dioxane, etc. are mentioned.

Examples of the ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-valerolactone, n-propyl acetate, iso-acetate acetate, n-butyl acetate and iso-acetate. Butyl, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl, methyl pentyl acetate, 2-ethylbutyl, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclocycloacetate Hexyl, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, and the like.

Among these solvents, ether solvents and ketone solvents are preferable, alkyl ether acetates of polyhydric alcohols and cyclic ketone solvents are more preferable, and propylene glycol methyl ether acetate and cyclohexanone are particularly preferable.

<[C] acid generator>

The acid generator (C) is a suitable component that the composition for forming a resist underlayer film may contain. When the composition for forming a resist underlayer film contains the [C] acid generator, the composition for forming a resist underlayer film can harden a resist underlayer film efficiently and can suppress intermixing of a resist underlayer film and a resist film. In addition, [C] acid generator can use together 1 type (s) or 2 or more types.

Examples of the acid generator [C] include an onium salt compound, a sulfonimide compound, and the like. Among these, onium salt compounds are preferable.

As an onium salt compound, a sulfonium salt, tetrahydrothiophenium salt, an iodonium salt, etc. are mentioned, for example.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, and triphenylsulfonium. 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfoniumtrifluoromethanesulfonate, 4-cyclohexyl Phenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfoniumperfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2. 1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfoniumtrifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium Nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfoniumperfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfo 2-bicyclo [2.2.1] and the like as -1,1,2,2- tetra fluoro hept-2-ethane sulfonate. Among them, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylphosphonium 1,1,2,2-tetrafluoro-6- (1-a Tancarbonyloxy) -hexane-1-sulfonate and 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate are preferable.

As the tetrahydrothiophenium salt, for example, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiopheniumtrifluoromethanesulfonate and 1- (4-n-butoxynaphthalene-1- 1) tetrahydrothiopheniumnonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiopheniumperfluoro-n-octanesulfonate, 1- ( 4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- ( 6-n-butoxynaphthalen-2-yl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiopheniumnonafluoro-n- Butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiopheniumperfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetra Hydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonei , 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiopheniumtrifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nona Fluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiopheniumperfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4- Hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, and the like. Of these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate and 1- (4-n-butoxynaphthalene-1 -Yl) tetrahydrothiopheniumperfluoro-n-octanesulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate are preferred. .

As the iodonium salt, for example, diphenyl iodonium trifluoromethanesulfonate, diphenyl iodonium nonafluoro-n-butanesulfonate, diphenyl iodonium perfluoro-n-octane sulfonate, Diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodoniumtrifluoro Methanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis ( 4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate etc. are mentioned. Of these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferable.

Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxyimide and N- (nonafluoro-n- Butanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxyimide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5 -Ene-2,3-dicarboxyimide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2. 1] hept-5-ene-2,3-dicarboxyimide, and the like.

As content of the [C] acid generator, 1 mass part or more and 50 mass parts or less are preferable with respect to 100 mass parts of [A] polymers, and 3 mass parts or more and 20 mass parts or less are more preferable. If it is less than 1 mass part, sclerosis | hardenability may fall, and when it exceeds 50 mass parts, applicability | paintability may fall.

<[D] crosslinking agent>

The crosslinking agent (D) is a suitable component that the composition for forming a resist underlayer film may contain. When the composition for forming a resist underlayer film contains a crosslinking agent [D], the composition for forming a resist underlayer film is formed by bonding a crosslinkable group of the [D] crosslinking agent and a polymer or another crosslinking agent molecule to be formed. An underlayer film can be hardened more. [D] As a crosslinking agent, the polyfunctional (meth) acrylate compound, an epoxy compound, the hydroxymethyl group substituted phenol compound, the compound which has an alkoxyalkylated amino group, etc. are mentioned, for example. Moreover, [D] crosslinking agent can use together 1 type (s) or 2 or more types.

As said polyfunctional (meth) acrylate compound, for example, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra ( Meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tree (meth ) Acrylate, ethylene glycol di (meth) acrylate, 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, Neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, bis (2-hydroxyethyl) A socyanurate di (meth) acrylate etc. are mentioned.

As said epoxy compound, a novolak-type epoxy resin, a bisphenol-type epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are mentioned, for example.

Examples of the hydroxymethyl group-substituted phenolic compound include 2-hydroxymethyl-4,6-dimethylphenol, 1,3,5-trihydroxymethylbenzene, and 3,5-dihydroxymethyl-4-methoxy Toluene [2,6-bis (hydroxymethyl) -p-cresol].

As a compound which has the said alkoxyalkylated amino group, for example, it exists in several molecule | numerators, such as (poly) methylolation melamine, (poly) methylolation glycoluril, (poly) methylolation benzoguanamine, (poly) methylolation urea, etc. The compound etc. which are nitrogen containing compounds which have an active methylol group, and whose at least one of the hydrogen atoms of the hydroxyl group of this methylol group were substituted by alkyl groups, such as a methyl group and a butyl group, etc. are mentioned. In addition, the compound which has the alkoxyalkylated amino group may be the mixture which mixed several substituted compounds, and may contain the oligomer component formed by partial self-condensation.

Among these crosslinking agents, compounds having an alkoxyalkylated amino group are preferable, and 1,3,4,6-tetrakis (methoxymethyl) glycoluril is more preferable.

As content of the [D] crosslinking agent, 3 mass parts or more and 100 mass parts or less are preferable with respect to 100 mass parts of [A] polymers, and 5 mass parts or more and 50 mass parts or less are more preferable. When the compounding quantity of the crosslinking agent (D) is less than 3 mass parts, there exists a possibility that the hardness of the formed resist underlayer film may become inadequate. On the other hand, when the compounding quantity of a crosslinking agent [D] exceeds 100 mass parts, applicability | paintability may deteriorate.

<Other optional components>

The composition for forming a resist underlayer film is other than the polymer [A] which is an essential component, the solvent [B] which is a suitable component, the [C] acid generator, and the [D] crosslinking agent in the range which does not impair the effect of this invention. It may also contain optional components. In addition, content of another arbitrary component can be suitably determined according to the objective.

<The manufacturing method of the composition for resist underlayer film forming>

The resist underlayer film-forming composition comprises a polymer [A] which is an essential component, a solvent [B] which is a suitable component, an acid generator and a [D] crosslinking agent, and other optional components, if necessary, in a predetermined ratio. It can manufacture by mixing.

<Formation method of resist underlayer film>

The formation method of the resist underlayer film of this invention is

(1-1) Process of forming a coating film on a board | substrate using the said composition for resist underlayer film formation (henceforth "a process (1-1)"), and

(1-2) A step of forming a resist underlayer film by heating the coating film (hereinafter also referred to as "step (1-2)")

Respectively.

Since the formation method of the said resist underlayer film has the said specific process, the formation method of the said resist underlayer film can form the resist underlayer film which has high heat resistance. It is preferable that the formation method of this resist underlayer film is used for formation of a resist underlayer film in the pattern formation method using the photolithographic method. Hereinafter, each process will be described.

[Step (1-1)]

In this process, a coating film is formed on a board | substrate using the said composition for resist underlayer film formation. As the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used. In addition, the formation method of the resist underlayer film forming composition to a board | substrate is not specifically limited, For example, it can carry out by a suitable method, such as rotational coating, casting | flow_spread coating, roll coating, etc ..

[Step (1-2)]

In this step, a resist underlayer film is formed by heating the coating film. Heating of the said coating film is normally performed in air | atmosphere. Heating temperature is 300 degreeC-500 degreeC normally, Preferably it is about 350 degreeC-450 degreeC. When heating temperature is less than 300 degreeC, oxidative crosslinking may not fully advance and there exists a possibility that the characteristic required as a resist underlayer film may not be expressed. The heating time is usually 30 seconds to 1200 seconds, preferably 60 seconds to 600 seconds.

It is preferable that the oxygen concentration at the time of coating film formation (curing) is 5 volume% or more. When the oxygen concentration at the time of forming the coating film is low, there is a fear that the oxidative crosslinking of the resist underlayer film does not proceed sufficiently, so that the characteristics required as the resist underlayer film may not be expressed.

Before the coating film is heated to a temperature of 300 ° C to 500 ° C, the coating film may be preheated to a temperature of 60 ° C to 250 ° C. Although the heating time in preheating is not specifically limited, It is preferable that they are 10 second-300 second, More preferably, they are 30 second-180 second. By performing this preheating, the dehydrogenation reaction can be efficiently carried out by evaporating the solvent in advance and making the membrane dense.

Moreover, in the formation method of the said resist underlayer film, although a coating film is hardened | cured by heating of the said coating film normally, a resist underlayer film is formed, but it contains a predetermined photocuring agent (crosslinking agent) in the composition for forming a resist underlayer film, A light irradiation process may be provided and photocured to form a resist underlayer film. The radiation exposed at this time is suitably from visible rays, ultraviolet rays, far ultraviolet rays, X rays, electron beams, γ rays, molecular rays, ion beams, and the like, depending on the kind of the [C] acid generator to be incorporated into the resist underlayer film forming composition. Is selected.

<Resist Underlayer Film>

The resist underlayer film of this invention is formed from the said composition for resist underlayer film formation. It is preferable that this resist underlayer film is used as a resist underlayer film in the pattern formation method using the photolithographic method. Since the resist underlayer film is formed from the composition for forming a resist underlayer film, the resist underlayer film has high heat resistance.

<Pattern forming method>

The pattern forming method of the present invention comprises:

(1) Process of forming a resist underlayer film on a board | substrate using the said composition for resist underlayer film formation (henceforth "a process (1)"),

(2) Process of forming a resist film on the said resist underlayer film using a resist composition (henceforth "a process (2)"),

(3) forming a resist pattern from the resist film (hereinafter also referred to as "step (3)"), and

(4) The resist pattern is used as a mask, and the resist underlayer film and the substrate are sequentially dry-etched to form a predetermined pattern on the substrate (hereinafter also referred to as "step (4)").

In the pattern forming method, since the resist underlayer film is formed using the composition for forming a resist underlayer film, the pattern forming method can improve the heat resistance of the resist underlayer film while maintaining the high bending resistance of the formed resist underlayer film pattern. .

The resist composition is a photoresist composition,

The step (3),

(3-1) step of exposing the resist film by selective radiation (hereinafter also referred to as "(3-1) step"), and

(3-2) Process of developing the exposed resist film (hereinafter also referred to as "(3-2) process")

It is preferable to include.

Since the said resist composition is a photoresist composition and the said process (3) includes the said process, the said pattern formation method can form a finer pattern simply and surely. Hereinafter, each process will be described.

[Step (1)]

In this step, a resist underlayer film is formed on the substrate using the composition for forming a resist underlayer film. It is preferable that it is a composition for resist underlayer film formation used for the pattern formation method using the photolithographic method as said composition for resist underlayer film formation. In addition, about the formation method of a resist underlayer film, the formation method of the resist underlayer film mentioned above can be applied as it is. The film thickness of the resist underlayer film formed in this step (1) is usually 0.05 µm to 5 µm.

Moreover, in this pattern formation method, after process (1), you may further have the process (1 ') of forming an intermediate | middle layer (intermediate film) on a resist underlayer film as needed. This intermediate layer is a layer to which these functions are imparted in order to further supplement the functions of the resist underlayer film and / or the resist film in forming the resist pattern, or to impart to them functions that they do not have. For example, when the antireflection film is formed as an intermediate layer in the pattern formation method using the photolithography method, the antireflection function of the resist underlayer film can be further supplemented.

This intermediate layer can be formed of an organic compound or an inorganic oxide. As said organic compound, it is a commercial item, For example, "DUV-42", "DUV-44", "ARC-28", "ARC-29" (above, Brewer Science); "AR-3", "AR-19" (above, Rohm and Haas), etc. are mentioned. As said inorganic oxide, "NFC SOG01", "NFC SOG04", "NFC SOG080" (above JSR manufacture), etc. are mentioned as a commercial item, for example. Moreover, polysiloxane, titanium oxide, alumina oxide, tungsten oxide, etc. which are formed by the CVD method can be used.

The method for forming the intermediate layer is not particularly limited, but a coating method, a CVD method, or the like can be used, for example. Among these, the coating method is preferable. When the coating method is used, the intermediate layer can be formed continuously after the resist underlayer film is formed. Moreover, it does not specifically limit as film thickness of an intermediate | middle layer, Although it selects suitably according to the function calculated | required by an intermediate | middle layer, 10 nm-3,000 nm are preferable, and 20 nm-300 nm are more preferable.

[Step (2)]

In this step, a resist film is formed on the resist underlayer film using the resist composition. Specifically, after applying a resist composition so that the resist film obtained may become a predetermined | prescribed film thickness, a resist film is formed by volatilizing the solvent in a coating film by prebaking.

Examples of the resist composition include a positive or negative chemically amplified resist composition containing a photoacid generator, a positive resist composition containing an alkali-soluble resin and a quinonediazide-based photosensitive agent, an alkali-soluble resin and a crosslinking agent. Photoresist compositions, such as negative resist compositions, the composition in the nanoimprint method of Unexamined-Japanese-Patent No. 2012-079865, and the nanostructured pattern manufacturing method of Unexamined-Japanese-Patent No. 2008-149447 The composition containing a block copolymer (henceforth a "self-organizing composition"), etc. are mentioned.

The total solid content concentration of the said resist composition is about 1-50 mass% normally. In addition, the resist composition is generally filtered through a filter having, for example, a pore size of about 0.2 μm and provided to form a resist film. In this step, a commercially available resist composition can also be used as it is.

It does not specifically limit as a coating method of a resist composition, For example, a spin coating method etc. are mentioned. In addition, although the temperature of prebaking is suitably adjusted according to the kind of resist composition used, etc., it is 30 degreeC-about 200 degreeC normally, Preferably it is 50 degreeC-150 degreeC.

[Step (3)]

In this step, a resist pattern is formed from the resist film. It does not specifically limit as this resist pattern formation method, For example, the method of forming using a nanoimprint method, the method of forming using a self-organizing composition, the method of forming using a photolithographic method, etc. are mentioned. Among these, the method of forming using a photolithography method from the viewpoint which can form a finer pattern simply and reliably is preferable. In the case of using the photolithography method, the step (3) usually includes the above step (3-1) and step (3-2).

[Step (3-1)]

In this step, the resist film is exposed by selective radiation. As radiation used for exposure, it selects suitably from visible light, an ultraviolet-ray, an ultraviolet-ray, an X-ray, an electron beam, a gamma ray, a molecular beam, an ion beam etc. according to the kind of photo-acid generator used for a photoresist composition. Among these, far ultraviolet rays are preferred, and KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ excimer laser light (wavelength 157 nm), Kr ₂ excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength) 134 nm) and extreme ultraviolet rays (13 nm wavelength etc.) are more preferable.

After the exposure, post-baking may be performed to improve the resolution, pattern profile, developability, and the like. Although the temperature of this postbaking is suitably adjusted according to the kind etc. of photoresist composition used, it is about 50 degreeC-about 200 degreeC normally, Preferably it is 70 degreeC-150 degreeC.

[Step (3-2)]

In this step, the exposed resist film is developed to form a resist pattern. The developer used in this step is appropriately selected depending on the kind of photoresist composition used. As the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, 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, Alkaline aqueous solution, such as 5-diazabicyclo [4.3.0] -5-nonene, is mentioned. An appropriate amount of water-soluble organic solvents such as alcohols such as methanol and ethanol, surfactants and the like may be added to these alkaline aqueous solutions.

After developing with the developing solution, a predetermined resist pattern is formed by washing and drying.

[Step (4)]

In this step, the resist underlayer film and the substrate are sequentially dry-etched using the resist pattern as a mask to form a predetermined pattern on the substrate. For this dry etching, for example, gas plasma such as oxygen plasma or the like is used. After the dry etching of the resist underlayer film, the substrate is subjected to dry etching to obtain a substrate having a predetermined pattern.

[Example]

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

In addition, the polystyrene reduced weight average molecular weight (Mw) of the polymer [A] used GPC columns (2 G2000HXL: 2, G3000HXL: 1) manufactured by Tosoh Corporation, and the flow rate was 1.0 ml / min and the elution solvent was tetrahydrofuran. It measured by gel permeation chromatography (detector: differential refractometer) which makes monodisperse polystyrene the standard on the analysis conditions of column temperature: 40 degreeC. In addition, each film thickness was measured using the spectroscopic ellipsometer (M2000D, J.A. WOOLLAM).

<Synthesis of polymer [A]>

Synthesis Example 1 Synthesis of (A-1)

In a separate flask equipped with a thermometer, 100 parts by mass of 1,2-diiodobenzene as a monomer, 100 parts by mass of 1,3-diethynylbenzene, and 3 parts of bis (triphenylphosphine) dichloropalladium as a catalyst under a nitrogen atmosphere. Part and 2 parts by mass of copper iodide, 200 parts by mass of piperidine as a basic compound, and 500 parts by mass of tetrahydrofuran as a solvent were mixed and stirred, followed by condensation polymerization reaction at 30 ° C. for 4 hours to obtain a reaction solution. . Methanol was added to this reaction liquid, reprecipitation was carried out, and the obtained precipitate was dried to obtain a polymer (A-1) having a structural unit represented by the following formula. Mw of (A-1) was 2,000.

Synthesis Example 2 Synthesis of (A-2)

In a separate flask equipped with a thermometer, under a nitrogen atmosphere, 100 parts by mass of 1,3-diiodobenzene as a monomer and 100 parts by mass of 4,4'-diethynyldiphenyl ether, bis (triphenylphosphine) dichloro as a catalyst 3 parts by mass of palladium and 2 parts by mass of copper (I) iodide, 200 parts by mass of piperidine as a basic compound, and 500 parts by mass of tetrahydrofuran as a solvent are mixed, and a condensation polymerization reaction is carried out at 30 ° C. for 4 hours while stirring, and the reaction liquid. Got.

Methanol was added to this reaction liquid, reprecipitation was carried out, and the obtained precipitate was dried to obtain a polymer (A-2) having a structural unit represented by the following formula. Mw of (A-2) was 3,000.

Synthesis Example 3 Synthesis of (A-3)

In a separate flask equipped with a thermometer, 100 parts by mass of 4,4 '-(di-o-iodobenzoyl) diphenyl ether as a monomer, 100 parts by mass of 4,4'-diethynyldiphenyl ether and a catalyst under a nitrogen atmosphere. 3 parts by mass of bis (triphenylphosphine) dichloropalladium and 2 parts by mass of copper (I) iodide, 200 parts by mass of piperidine as a basic compound, and 500 parts by mass of tetrahydrofuran as a solvent were mixed and stirred at 30 ° C. Condensation polymerization reaction was performed for 4 hours, and the reaction liquid was obtained. Methanol was added to this reaction liquid, reprecipitation was carried out, and the obtained precipitate was dried to obtain a polymer (A-3) having a structural unit represented by the following formula. Mw of (A-3) was 4,000.

Synthesis Example 4 Synthesis of (a-1)

In a separate flask equipped with a thermometer, 100 parts by mass of 1,3-diethynylbenzene as a monomer and 150 parts by mass of phenylacetylene, 100 parts by mass of copper chloride as a catalyst, and 1,000 parts by mass of pyridine as a basic compound are mixed in a nitrogen atmosphere. Condensation polymerization reaction was performed at 30 degreeC for 1 hour, stirring, and the reaction liquid was obtained. Isopropyl alcohol / water (mass ratio: 1/1) was added to this reaction liquid, reprecipitation was carried out, and the obtained precipitate was dried to obtain a polymer (a-1) having a structural unit represented by the following formula. Mw of (a-1) was 1,500.

<Preparation of the composition for forming a resist underlayer film>

It showed below about each component other than the polymer [A].

[B] solvent

B-1: cyclohexanone

[C] acid generators

Compound represented by the following formula (C-1)

[D] crosslinking agent

The compound represented by the following general formula (D-1) (Nicalak N-2702, the acid and chemical preparation)

Example 1

10 mass parts of (A-1) as a polymer [A] and 100 mass parts of (B-1) as a solvent [B] were mixed, and the solution was obtained. And this solution was filtered with the membrane filter of 0.1 micrometer of pore diameters, and the composition for resist underlayer film formation was manufactured.

[Examples 2 to 4 and Comparative Example 1]

Except having made the kind and compounding quantity (mass part) of each component to mix as described in Table 1, it operated like Example 1, and produced the composition for each resist underlayer film formation. In addition, the column represented by "-" in Table 1 shows that the component is not mix | blended.

<Synthesis of Base Polymer Used in Photoresist Composition>

Synthesis Example 5

11.92 g of compound (M-1), 41.07 g of compound (M-2), 15.75 g of compound (M-3), 11.16 g of compound (M-4), 20.10 g of compound (M-5), and a compound represented by the following formula: 3.88 g of dimethyl2,2'-azobis (2-isobutyronitrile) was dissolved in 200 g of 2-butanone. 100 g of 2-butanone was added to a 1,000 ml three-necked flask, purged with nitrogen for 30 minutes, and then heated to 80 ° C. with stirring. The prepared solution was dripped over 4 hours, and further aged at 80 degreeC for 2 hours after completion | finish of dripping. After completion of the polymerization, the polymerization solution was cooled to 30 ° C or lower by water cooling. The polymerization solution was concentrated under reduced pressure with an evaporator until the mass of the polymerization solution became 200 g. Thereafter, the polymerization solution was poured into 1,000 g of methanol, and a reprecipitation operation was performed. The precipitated slurry was suction filtered and separated by filtration, and the solid was washed three times with methanol. The obtained powder was vacuum dried at 60 degreeC for 15 hours, and 88.0g (yield 88%) of white powder (base polymer) was obtained. Mw of the obtained base polymer was 9,300 and Mw / Mn was 1.60. ^As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from compound (M-1), (M-2), (M-3), (M-4), and (M-5) is 16, respectively. Mol%, 26 mol%, 19 mol%, 11 mol% and 28 mol%. In addition, ¹³ C-NMR analysis used the Nippon Denshi make, JNM-ECP500.

<Synthesis of Fluorine Atom-Containing Polymer Used in Photoresist Composition>

[Synthesis Example 6]

3.8 g of compound (M-6) and 1.2 g of compound (M-7) represented by the following formula are dissolved in 10 g of 2-butanone, and 0.09 g of 2,2'-azobis (2-isobutyronitrile) is dissolved. Into a 100 ml three-necked flask. After nitrogen purging for 30 minutes, the reaction kettle was heated to 80 ° C while stirring, and the polymerization reaction was carried out for 6 hours with the heating start being the polymerization start time. After the completion of the polymerization, the polymerization solution was cooled to 30 ° C or less by water cooling, and concentrated under reduced pressure until the mass of the polymerization solution became 12.5 g by an evaporator. The polymerization solution was slowly poured into 75 g of n-hexane cooled to 0 ° C to precipitate a solid content. The liquid mixture was filtered, solid content was wash | cleaned with n-hexane, and the obtained powder was vacuum-dried at 40 degreeC for 15 hours, and 3.75g (yield 75%) of white powder (fluorine atom containing polymer) was obtained. Mw of the fluorine atom-containing polymer was 9,400 and Mw / Mn was 1.50. ^As a result of ¹³ C-NMR analysis, the content rates of the structural units derived from the compounds (M-6) and (M-7) were 68.5 mol% and 31.5 mol%, respectively. The fluorine atom content was 21.4 mass%.

<Production of Photoresist Composition>

Production Example 8 parts by mass of triphenylsulfonium trifluoromethanesulfonate as the acid generator, 100 parts by mass of the base polymer obtained in Synthesis Example 5, 5 parts by mass of the fluorine atom-containing polymer obtained in Synthesis Example 6, and an acid diffusing agent As a yesterday, 0.6 parts by mass of Nt-amyloxycarbonyl-4-hydroxy piperidine was added to 1,881 parts by mass of propylene glycol monomethyl ether acetate, 806 parts by mass of cyclohexanone, and 200 parts by mass of γ-butyrolactone to obtain a solution. It was. This solution was filtered with a membrane filter having a pore size of 0.1 mu m to prepare a photoresist composition.

<Evaluation>

Refractive index, attenuation coefficient, bending resistance and heat resistance were measured, and the results are shown in Table 2.

Refractive Index and Attenuation Coefficient

Each of the above-described compositions for forming a resist underlayer film was spin-coated on a silicon wafer surface having a diameter of 8 inches as a substrate, and then heated at 350 ° C. for 2 minutes to form a resist underlayer film having a thickness of 250 nm. And the refractive index and the attenuation coefficient in wavelength 193nm of the formed resist underlayer film were measured using the spectroscopic ellipsometer (M2000D, J.A. WOOLLAM). At this time, the case where the refractive index was 1.3 or more and 1.6 or less and the attenuation coefficients were 0.2 or more and 0.8 or less was made favorable.

[Flexion resistance]

A silicon oxide film was deposited by 0.3 占 퐉 on a silicon wafer having a diameter of 12 inches by CVD. Next, each resist underlayer film forming composition was spin-coated and heated at 350 ° C. for 120 seconds to form a resist underlayer film having a film thickness of 0.25 μm. Subsequently, after spin coating the intermediate layer composition solution (NFC SOG508, manufactured by JSR) for the three-layer resist process on the resist underlayer film, the substrate was heated at 200 ° C. for 60 seconds, and then heated at 300 ° C. for 60 seconds to obtain a film thickness of 0.04 μm. An interlayer film was formed. Then, the photoresist composition obtained by the said manufacture example was spin-coated on this intermediate | middle layer film, and prebaked at 100 degreeC for 60 second, and the resist film with a film thickness of 0.1 micrometer was formed.

Subsequently, the ArF immersion exposure apparatus (lens numerical aperture 1.30, exposure wavelength 193nm, NIKON product) was used, and exposure time optimal exposure was performed through the mask. Subsequently, after post-baking at 100 degreeC for 60 second, the resist film was developed using 2.38 mass% tetramethylammonium hydroxide aqueous solution. Thereafter, the mixture was washed with water and dried to form a positive resist pattern. Subsequently, using the resist film in which this pattern was formed as a mask, the intermediate layer film was dry-etched with tetrafluorocarbon gas using a reactive ion etching (RIE) etching apparatus (Telius SCCM, manufactured by Tokyo Electron), and the resist film was used. The etching process was stopped in the place where the intermediate | middle layer film located under the opening part disappeared, and the resist pattern was transferred to the intermediate | middle layer film.

Subsequently, using the intermediate layer film which transferred the said resist pattern as a mask, dry-etching process with the mixed gas of oxygen and nitrogen using the said etching apparatus, and etching process in the place where the resist underlayer film located under the intermediate layer opening part was lost. The pattern of the intermediate layer film was transferred to the resist underlayer film. Subsequently, using the resist underlayer film to which the pattern of the intermediate | middle layer film was transferred was used as a mask, it dry-etched with the mixed gas of carbon tetrafluoride and argon using the said etching apparatus, and the silicon oxide film located under the resist underlayer film opening part is 0.1 The etching process was stopped where it removed by the micrometer.

And the shape of the so-called line-and-space pattern in which the linear patterns were arranged at equal intervals among the resist underlayer film patterns remaining on the substrate was observed by a scanning electron microscope (SEM). This line-and-space pattern has a fixed repetition interval of 84 nm and 100 linear patterns are arranged at equal intervals, and this is regarded as one set. There are 21 sets of pattern groups having different pattern widths on the same substrate, and the pattern widths are each 1 nm from 50 nm to 30 nm. The pattern width here is the width | variety per one of the linear patterns arrange | positioned at equal intervals formed with a resist underlayer film. Of the same design patterns on a substrate, five arbitrary patterns were observed by the said SEM, and the pattern of each pattern width was observed, and this observation result was made into bending tolerance. At this time, if all the patterns of the resist underlayer film stood vertically, the bending resistance was good "A", and if it was bent at one place, it was set as "B".

[Heat resistance]

On the 8-inch-diameter silicon wafer, each coating composition for resist underlayer film formation was spin coated to form a coating film (resist underlayer film), and the film thickness of the coating film was measured using the spectroscopic ellipsometer (this measured value). Is X). Next, this resist underlayer film was heated at 350 degreeC for 120 second, and the film thickness of the resist underlayer film after heating was measured using the said spectral ellipsometer (this measurement value is set to Y). And the film thickness reduction rate (DELTA) FT (%) ((DELTA) FT (%) = 100x (X-Y) / X) of the resist underlayer film before and behind heating was computed, and this calculated value was made into heat resistance (%). In addition, as the value of the heat resistance (%) is smaller, there are fewer sublimates and film decomposition products generated at the time of heating the resist underlayer film, indicating that it is good (high heat resistance).

As is apparent from Table 2, the compositions for forming the resist underlayer films of Examples 1 to 4 satisfy the characteristics relating to the refractive index, the attenuation coefficient, and the bending resistance, and have higher heat resistance than Comparative Example 1.

INDUSTRIAL APPLICABILITY The present invention satisfies the characteristics related to the refractive index and the attenuation coefficient required for a resist underlayer film, and can form a resist underlayer film having high heat resistance while maintaining high bending resistance of the formed resist underlayer film pattern. A composition, a resist underlayer film, its formation method, and a pattern formation method can be provided. Therefore, according to this invention, the manufacturing yield of a semiconductor device can be improved in a semiconductor manufacturing process, and it can use suitably for the manufacturing process of the semiconductor device which further refines a pattern.

Claims (10)

[A] A composition for forming a resist underlayer film containing a polymer having a structural unit (I) represented by the following general formula (1).

(In Formula (1), Ar ¹ and Ar ² are each independently a divalent group represented by the following formula (2).)

(Formula (2) of, R ¹ and R ² each independently is an aromatic divalent group, R ³ represents a single bond, -O-, -CO-, -SO- or -SO ₂ -, and, a is from 0 to An integer of 3, provided that when a is 2 or more, a plurality of R ² and R ³ may be the same or different, respectively) The composition for forming a resist underlayer film according to claim 1, wherein R ¹ and R ² in the formula (2) are each independently represented by the following formula (3).

Of (formula (3), R ⁴ is a hydroxyalkyl group of a halogen atom, a hydroxy group, a cyano group, a nitro group, a C 1 -C 20 monovalent hydrocarbon group, an alkoxy group or a group having 1 to 20 carbon atoms having from 1 to 20, b Is an integer of 0 to 6, provided that when b is 2 or more, a plurality of R ⁴ may be the same or different, and c is 0 or 1) The composition for forming a resist underlayer film according to claim 1 or 2, wherein the polystyrene reduced weight average molecular weight of the polymer [A] is 500 or more and 10,000 or less. The composition for forming a resist underlayer film according to any one of claims 1 to 3, further comprising a solvent [B]. The composition for forming a resist underlayer film according to any one of claims 1 to 4, further comprising an acid generator (C). The composition for forming a resist underlayer film according to any one of claims 1 to 5, further comprising [D] a crosslinking agent. (1-1) Process of forming a coating film on a board | substrate using the composition for resist underlayer film forming in any one of Claims 1-6, and
(1-2) Process of forming a resist underlayer film by heating the said coating film
The formation method of the resist underlayer film which has this. The resist underlayer film formed from the composition for resist underlayer film forming in any one of Claims 1-6. (1) Process of forming a resist underlayer film on a board | substrate using the composition for resist underlayer film forming in any one of Claims 1-6,
(2) forming a resist film on the resist underlayer film using a resist composition;
(3) forming a resist pattern from the resist film, and
(4) A step of forming a predetermined pattern on the substrate by sequentially dry etching the resist underlayer film and the substrate using the resist pattern as a mask.
&Lt; / RTI &gt; The method of claim 9, wherein the resist composition is a photoresist composition,
The step (3),
(3-1) exposing the resist film by selective radiation; and
(3-2) Process of developing the exposed said resist film
Pattern forming method comprising a.