JP4639915B2 - Composition for resist underlayer film - Google Patents

Description

  The present invention relates to a resist underlayer film composition that contains a polymer having a diyne structure and is suitable for microfabrication in a lithography process using various types of radiation, particularly for the production of highly integrated circuit elements.

  It is well known to polymerize various monosubstituted acetylenes to obtain diyne compounds. Since such diyne compounds have a unique structure and are highly reactive, not only chemical modification by reaction with various reactants has been studied, but also various physical properties such as heat resistance have been reported. Focused materials and applications have been developed. In terms of developing diyne compounds that are rich in reactivity and can be expected to have various properties, it is extremely significant to provide their derivatives from an academic and application standpoint. Alkyl groups and aromatic ring groups have already been developed. Diyne compounds having various substituents have been synthesized. However, no examples of applying these diyne compounds to resist underlayer film applications for semiconductor production have been reported so far.

  In the manufacturing method of an integrated circuit element, in order to obtain a higher degree of integration, the process size using a multilayer resist process is being miniaturized. In this process, a liquid resist underlayer film composition is first applied on a substrate, and then a liquid photoresist composition is further applied. Next, the mask pattern is transferred by a reduction projection exposure apparatus (stepper) and developed with an appropriate developer to obtain a photoresist pattern. Subsequently, this pattern is transferred to the resist underlayer film by dry etching. Finally, by transferring the resist underlayer film pattern to the substrate by dry etching, a substrate with a desired pattern can be obtained. A multilayer process using one type of resist underlayer film is called a two-layer resist process, and when two types are used, it may be called a three-layer resist process.

  In general, the resist underlayer film functions as an antireflection film that absorbs radiation reflected from the substrate. In general, a material having a high carbon content is used for the resist underlayer film directly on the substrate. When the carbon content is large, the etching selectivity at the time of substrate processing is improved, and more accurate pattern transfer is possible. A thermosetting novolak is particularly well known as such an underlayer film. In addition, it is known that a composition containing a polymer having an acenaphthylene skeleton exhibits good characteristics as an antireflection film (see, for example, Patent Documents 1 and 2).

JP 2000-143937 A JP 2001-40293 A

  However, with further miniaturization of the etching pattern, over-etching of the resist underlayer film becomes a big problem, and precise pattern transfer performance and improvement in etching selectivity are required. In addition, in the dual damascene process which has been attracting attention in recent years, improvement of the embedding property of the resist underlayer film composition in the via is also required.

  INDUSTRIAL APPLICABILITY The present invention provides a resist underlayer film that has a function as an antireflection film, can form a resist underlayer film with good pattern transfer performance and etching selectivity, and has good embedding properties in vias in a dual damascene process. Providing a composition.

  As a result of intensive studies to develop such a resist underlayer film composition, the present inventors have found that diyne derivatives are extremely useful as compounds that can exhibit the above characteristics in the resist underlayer film composition, The present inventors have found that it has higher etching selectivity and burying property in vias than conventional resist underlayer film compositions. That is, the present invention provides the following composition for a resist underlayer film.

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

〔式（１）において、Ｒ^１は２価の芳香族基を示す。〕

In [Equation (1), ^{R 1} is a divalent aromatic group. ]

[2] A resist underlayer film composition containing a polymer having a structural unit represented by the following formula (2).

[In Formula (2), R ² And R ³ Are independently a divalent aromatic group, and A represents a divalent organic group. ]

[ 3 ] The resist underlayer film composition as described in [1] or [2] above, wherein the polymer has a polystyrene-equivalent weight average molecular weight of 500 to 10,000 as measured by gel permeation chromatography.

[ 4 ] The composition for a resist underlayer film according to any one of [1] to [ 3 ], further containing a solvent.

[ 5 ] The composition for a resist underlayer film according to any one of [1] to [ 4 ], further containing an acid generator.

[ 6 ] The composition for a resist underlayer film according to any one of [1] to [ 5 ], further containing a crosslinking agent.

  Since the composition for a resist underlayer film of the present invention contains a polymer having the structural unit represented by the above formula (1) or (2), it has a function as an antireflection film and has pattern transfer performance and etching selection. It is possible to form a resist underlayer film having good properties and to have good embedding properties in vias in a dual damascene process.

  Hereinafter, the composition for a resist underlayer film of the present invention will be described in detail based on specific examples, but the present invention is not limited to the following specific examples.

The resist underlayer film composition of the present invention contains a polymer having a structural unit represented by the following formula (1) (hereinafter sometimes referred to as structural unit (1)) . The resist underlayer film composition of the present invention contains a polymer having a structural unit represented by the following formula (2) (hereinafter sometimes referred to as structural unit (2)).

〔式（１）において、Ｒ^１は２価の芳香族基を示す。〕

In [Equation (1), ^{R 1} is a divalent aromatic group. ]

〔式（２）において、Ｒ ^２ 及びＲ ^３ が相互に独立に２価の芳香族基であり、Ａは２価の有機の基を示す。〕

[In Formula (2), R ² and R ³ are each independently a divalent aromatic group, and A represents a divalent organic group. ]

-Structural unit (1)-
In the structural unit (1), the divalent organic group represented by R ¹ is preferably a group having 1 to 20 carbon atoms. Preferred examples include a divalent aromatic group; a divalent saturated aliphatic group; and a divalent unsaturated aliphatic group. These groups may be substituted with a substituent. Preferred substituents include halogen atom; hydroxyl group; mercapto group; carboxyl group; ester group; nitro group; sulfonic acid group; A divalent group substituted with one or more or one or more of these substituents is also preferred.

  Examples of the divalent aromatic group include a phenylene group, a tolylene group, a dimethylphenylene group, a trimethylphenylene group, an aminophenylene group, a pyridylene group, an ethynylphenylene group, a biphenylene group, and a naphthylene group.

  The divalent saturated aliphatic group is preferably a linear or branched alkylene group having 1 to 6 carbon atoms, specifically, a methylene group, an ethylene group, an n-propylene group, an i-propylene group, An n-butylene group, an i-butylene group, a sec-butylene group, a t-butylene group, and the like can be given.

  The divalent unsaturated aliphatic group is preferably a linear or branched alkenylene group having 2 to 6 carbon atoms, and specifically, a vinylidene group, an arylene group, a 1-butenediyl group, or a 2-butenediyl group. Etc.

  Among these, a divalent aromatic group is preferable, and a phenylene group and a tolylene group are particularly preferable. More specific preferred examples of the structural unit (1) include a structural unit represented by the following formula (3).

〔式（３）において、Ｒはメチル基を示し；ｎは０又は１の整数を示す〕

[In Formula (3), R represents a methyl group; n represents an integer of 0 or 1]

-Structural unit (2)-
In the structural unit (2), the divalent organic group represented by R ² and R ^3, same can be mentioned for R ¹ in the above-mentioned structural units (1), similarly to R ^1, 2 Among Valent aromatic groups are preferred, and phenylene groups and tolylene groups are particularly preferred.

  The divalent organic group represented by A in the structural unit (2) is preferably a group having 1 to 20 carbon atoms. Preferred examples include a divalent saturated aliphatic group; a divalent unsaturated aliphatic group; and a divalent group including a carbonyl group. These groups may be substituted with a substituent. Preferred substituents include halogen atom; hydroxyl group; mercapto group; carboxyl group; ester group; nitro group; sulfonic acid group; A divalent group substituted with one or more or one or more of these substituents is also preferred.

  The divalent saturated aliphatic group is preferably a linear or branched alkylene group having 1 to 6 carbon atoms, specifically, a methylene group, an ethylene group, an n-propylene group, an i-propylene group, An n-butylene group, an i-butylene group, a sec-butylene group, a t-butylene group, and the like can be given.

  The divalent unsaturated aliphatic group is preferably a linear or branched alkenylene group having 2 to 6 carbon atoms, and specifically, a vinylidene group, an arylene group, a 1-butenediyl group, or a 2-butenediyl group. Etc.

  The divalent group containing a carbonyl group is preferably a group containing an ester bond or a group containing an amide bond. Specific examples include an iminocarbonyl group, a carbonylimino group, an oxycarbonyl group, a carbonyloxy group, and a divalent group in which two of these groups are bonded to an aromatic ring.

  Among these, a group containing a carbonyl group is preferable, and an iminocarbonyl group (—NH (C═O) —), a carbonylimino group (— (C═O) —NH—), an oxycarbonyl group (—O— (C═O) )-), A carbonyloxy group (— (C═O) —O—), a divalent group in which two of these groups are bonded to an aromatic ring (for example, —NH (C═O) —Ar— (C═ O) -NH-, wherein Ar represents an aromatic ring) is particularly preferred. More specific preferred examples of the structural unit (2) include structural units represented by the following formulas (4) to (6).

〔式（４）において、Ｒはメチル基を示し；ｎは０又は１の整数を示す〕

[In the formula (4), R represents a methyl group; n represents an integer of 0 or 1]

〔式（５）において、Ｒはメチル基を示し；ｎは０又は１の整数を示す〕

[In Formula (5), R represents a methyl group; n represents an integer of 0 or 1]

〔式（６）において、Ｒはメチル基を示し；ｎは０又は１の整数を示す〕

[In Formula (6), R represents a methyl group; n represents an integer of 0 or 1]

-Polymer-
The polymer containing the structural unit (1) (hereinafter sometimes referred to as the polymer (1)) is a diyne corresponding to the structural unit (1) as a monomer and optionally other copolymerizable compounds, for example, It can be obtained by a coupling reaction using a metal catalyst. The polymer containing the structural unit (2) (hereinafter sometimes referred to as the polymer (2)) is a diyne corresponding to the structural unit (2) as a monomer and optionally with other copolymerizable compounds. For example, it can be produced by polymerizing in an appropriate polymerization form such as bulk polymerization or solution polymerization by condensation polymerization, radical polymerization, anionic polymerization, cationic polymerization or the like forming an ester bond or an amide bond. As the polymer (1), a polymer containing the structural unit represented by the above formula (3) as one of repeating units is preferable, and poly (diethynylbenzene) is particularly preferable. As the polymer (2), a polymer having at least one of the above formulas (4) to (6) as one of repeating units is preferable.

  Other copolymerizable compounds in the polymer (1) include ethynyl styrene, propargylic acid, 6-hexynoic acid, 2-propyn-1-ol, 1-butyn-3-ol, 3-butyn-3-ol, 1 -Pentyn-3-ol, 4-pentyn-1-ol, 3-ethynylaniline, 4-ethynylaniline, phenylacetylene and the like can be mentioned. As other copolymerizable compounds in the polymer (2), terephthalic acid, isophthalic acid, pyromellitic acid, acenaphthylenecarboxylic acid, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4- Examples thereof include phenylenediamine.

  The content of structural units derived from other copolymerizable compounds in the polymers (1) and (2) is preferably not more than 80 mol%, more preferably not more than 60 mol%, especially based on the total structural units. Preferably it is 40 mol% or less. If this content is too large, the effect of the diyne structure may not be sufficiently obtained.

  The weight average molecular weight in terms of polystyrene (hereinafter referred to as “Mw”) measured by gel permeation chromatography of the polymers (1) and (2) is 500 to 10,000, preferably 1,000 to 5,000. . If the molecular weight is too small, the in-plane film-forming property tends to be remarkably deteriorated, and if it is too large, the in-plane uniformity of the film tends to be impaired.

  The polymers (1) and (2) have a property of causing a crosslinking reaction between molecular chains by heating or exposure, and are particularly useful for a resist underlayer film composition described later. The polymers (1) and (2) can be used alone or in combination of two or more.

  The resist underlayer film composition of the present invention contains the polymer (1) and / or the polymer (2), and this composition usually contains the polymer (1) and / or the polymer (2). It is a liquid composition containing a solvent to dissolve.

-Solvent-
The solvent used in the resist underlayer film composition of the present invention is not particularly limited as long as it can dissolve the polymers (1) and (2).
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 thereof include lactones such as γ-butyrolactone, and these can be appropriately selected and used.

  Among 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 obtained composition is usually 0.01 to 70% by mass, preferably 0.05 to 60% by mass, more preferably 0.1 to 50% by mass. is there.

-Additives-
In the composition for a resist underlayer film of the present invention, various kinds of agents such as an acid generator, a crosslinking agent, 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. An additive can be blended, and it is particularly preferable to blend an acid generator and / or a crosslinking agent.

The acid generator is a component that generates an acid upon exposure or heating.
Examples of the acid generator that generates an acid upon exposure (hereinafter referred to as “photoacid generator”) include:
Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, diphenyliodonium hexafluoroantimonate,
Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium naphthalenesulfonate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate,
Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10-camphorsulfonate, 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, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1 -(4-t-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-tetrahydrofuranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1 -[4- (2-tetrahydropyranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate,
Onium salt photoacid generators such as 1- (4-benzyloxy) tetrahydrothiophenium trifluoromethanesulfonate, 1- (naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate;

Halogen-containing compound-based photoacid generators 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 Diazoketone compound-based photoacid generators such as 1,2-naphthoquinonediazide-5-sulfonic acid ester;
Sulfone compound photoacid generators 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 compound photoacid generators such as carbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate.

  Among these photoacid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) Etc. iodonium naphthalene sulfonate is preferred. The photoacid generators can be used alone or in admixture of two or more.

  Examples of the acid generator that generates an acid by heating (hereinafter referred to as “thermal acid generator”) include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl, and the like. Tosylate, alkyl sulfonates and the like can be mentioned. These thermal acid generators can be used alone or in admixture of two or more. Moreover, a photo-acid generator and a thermal acid generator can also be used together as an acid generator.

  The compounding amount of the acid generator is usually 5,000 parts by mass or less, preferably 0.1 to 1,000 parts by mass, more preferably 0.1 to 100 parts by mass of the solid content of the resist underlayer film composition. 100 parts by mass. The resist underlayer film composition of the present invention contains a photoacid generator and / or a thermal acid generator, thereby effectively causing a crosslinking reaction between the molecular chains of each polymer at a relatively low temperature including normal temperature. It becomes possible.

  The crosslinking agent is a component having an action of preventing intermixing between the obtained resist underlayer film and the resist film formed thereon and further preventing cracking of the resist underlayer film. 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 ″. -Methylidene trisphenol, 4,4'-
Examples thereof include trinuclear phenols such as [1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol; polyphenols such as novolak. Among these polynuclear phenols, 4,4 ′-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol, novolac and the like can be mentioned. 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, 6 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-based curing agents such as 106 and 130 (above, Mitsui Cyanamid Co., Ltd.); 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 5,000 parts by mass or less, preferably 1,000 parts by mass or less per 100 parts by mass of the solid content of the resist underlayer film composition.

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 such as α-chloroacrylic acid, (meth) acrylic acid salt, (meth) acrylic acid ester, (meth) acrylic acid halide or derivatives thereof; poly (meth) 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 a component that has an action of preventing intermixing between the resist underlayer film obtained and the resist film formed thereon, which is cured by heating and becomes insoluble in a solvent. It 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 mass or less, preferably 10 parts by mass or less, per 100 parts by mass of the polymer for each resist underlayer film composition.

  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 compounding amount of the radiation absorber is usually 100 parts by mass or less, preferably 50 parts by mass or less per 100 parts by mass of the solid content of the resist underlayer film 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.), F-top 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 mass or less, preferably 10 parts by mass or less per 100 parts by mass of the solid content of the resist underlayer film composition. Furthermore, examples of additives other than those described above include storage stabilizers, antifoaming agents, and adhesion aids.

-Method of forming resist pattern using resist underlayer film-
The resist pattern forming method using each resist underlayer film composition of the present invention (hereinafter simply referred to as “composition”) is usually, for example, 1) coating the composition on a substrate, and then applying the resulting coating. A step of forming a resist underlayer film by curing the film, 2) a step of applying a resist composition solution on the resist underlayer film, and prebaking the obtained coating film to form a resist film, and 3) the resist coating film Are selectively exposed through a photomask, 4) a step of developing the exposed resist film, and 5) a step of etching the resist underlayer film.

  In step 1), for example, a silicon wafer, a wafer coated with aluminum, or the like can be used as the substrate. The composition can be applied by an appropriate method such as spin coating, cast coating, roll coating or the like. Thereafter, the coating film is cured by exposure and / or heating. The radiation to be exposed is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, γ-ray, molecular beam, ion beam and the like according to the type of photoacid generator used. When the composition contains a photoacid generator and is exposed, the coating film can be effectively cured even at room temperature. The heating temperature is usually about 90 to 350 ° C., preferably about 200 to 300 ° C. When the composition contains a thermal acid generator, the coating film can be effectively used even at about 90 to 150 ° C., for example. It can be cured. 1) The film thickness of the resist underlayer film formed in the step is usually 0.1 to 5 μm.

  Next, in step 2), the resist composition solution is applied onto the resist underlayer film so that the resulting resist film has a predetermined thickness, and then pre-baked to volatilize the solvent in the film, thereby resisting the resist. Form a 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 photoacid generator, a positive resist composition comprising an alkali-soluble resin and a quinonediazide-based photosensitizer, and an alkali-soluble resin. Examples thereof include a negative resist composition comprising a crosslinking agent.

  The resist composition solution used when forming the resist film on the resist underlayer film has a solid content concentration of usually about 5 to 50% by mass, and is generally filtered with a filter having a pore size of about 0.2 μm, for example. And used for forming a resist film. In this step, a commercially available resist composition solution can be used as it is.

Next, in the step 3), as the radiation used for exposure, visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, gamma rays, molecules are used depending on the type of photoacid generator used in the resist composition. It is suitably selected from a line, an ion beam, etc., but is preferably 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 ( A wavelength of 147 nm), an ArKr excimer laser (wavelength of 134 nm), extreme ultraviolet light (wavelength of 13 nm, etc.) and the like are preferable.

  Next, in step 4), the resist film after exposure is developed, washed, and dried to form a predetermined resist pattern. In this step, post-baking can be performed after exposure and before development in order to improve resolution, pattern profile, 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 Alkaline aqueous solution etc. may 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 these alkaline aqueous solutions.

  Next, in step 5), using the obtained resist pattern as a mask, the resist underlayer film is dry-etched using gas plasma such as oxygen plasma to obtain a resist pattern for processing a predetermined substrate.

  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” and “%” are based on mass unless otherwise specified.

Molecular weight measurement:
In the following Example 1 and Preparation Example 1, the Mw of the obtained resin and polymer was a GPC column (G2000HXL: 2, G3000HXL: 1) manufactured by Tosoh Corporation, flow rate: 1.0 ml / min. Measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under the analysis conditions of elution solvent: tetrahydrofuran and column temperature: 40 ° C.

The performance evaluation of the resist underlayer film composition was performed as follows.
optical properties:
A resist underlayer film composition was spin-coated on a silicon wafer having a diameter of 8 inches, and then heated on a hot plate at 300 ° C. for 120 seconds to form a resist underlayer film having a thickness of 0.3 μm. The film was measured for refractive index (n value) and absorbance (k value) at a wavelength of 633 nm using a spectroscopic ellipsometer UV-1280E manufactured by KLA-TENCOR.

Formation of positive resist pattern for ArF:
A resist underlayer film composition was spin-coated on a silicon wafer having a diameter of 8 inches and then heated on a hot plate at 180 ° C. and 300 ° C. for 60 seconds to form an underlayer film having a thickness of 0.3 μm. Thereafter, an interlayer composition solution for a three-layer resist process (trade name NFC SOG041, manufactured by JSR Corporation) is spin-coated on this resist underlayer film, and heated on a hot plate at 200 ° C. and 300 ° C. for 60 seconds respectively. Thus, an intermediate layer film having a thickness of 0.11 μm was formed. Thereafter, the ArF resist composition solution obtained in Reference Example 1 described later was spin-coated thereon, and prebaked on a 130 ° C. hot plate for 90 seconds to form a resist film having a thickness of 0.5 μm. 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.

Standing wave prevention effect:
In the manner described above, the resist underlayer film was formed, the resist film was formed, exposed and developed, and the presence or absence of the standing wave on the resist film was observed and evaluated by a scanning electron microscope.
Intermixing prevention effect:
The resist underlayer film is formed as described above, and the obtained resist underlayer film is immersed in cyclohexanone at room temperature for 1 minute, and the film thickness change before and after immersion is measured using a spectroscopic ellipsometer UV1280E (manufactured by KLA-TENCOR). When the measurement was made, the case where no change in film thickness was observed was evaluated as “present”, and the case where a film thickness change was observed was evaluated as “not present”.
Via embedding:
After forming a resist underlayer film as described above for a SiO ₂ substrate having a via hole having a diameter of 0.14 μm and a depth of 1.0 μm on a silicon wafer, is the via completely buried by the resist underlayer film? Whether or not was evaluated by cross-sectional SEM observation.
Etch resistance:
The substrate on which the resist underlayer film was formed as described above was etched for a specified time under general oxide film etching conditions using an etching apparatus manufactured by SHINKO. The etching amount per minute was calculated from the difference in film thickness before and after etching. It can be said that the smaller the etching amount, the higher the etching resistance.

Example 1 (Synthesis of polydiethynylbenzene)
To a solution obtained by dissolving 6.25 g of metadiethynylbenzene and 10.13 g of phenylacetylene in 200 ml of pyridine, 6.3 g of copper (I) chloride was added at room temperature while stirring the solution. The reaction solution was then stirred for 1 hour before the product was reprecipitated in a large volume of water / isopropyl alcohol one-to-one solution. The product was washed with water and then dissolved in toluene. This solution was washed twice with 3% oxalic acid and twice with water, and then the solution was concentrated under reduced pressure and solidified to obtain 8.6 g of a solid having Mw = 1,000. This solid was used as a resist underlayer film composition as a cyclohexanone solution.

Preparation Example 1 (Preparation of resist composition solution for ArF)
In a separable flask equipped with a reflux tube, 8-methyl-8-t-butoxycarbonylmethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene 29 parts, 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, azobisisobutyronitrile 4 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. When dried, the content of the structural 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. The resin was obtained in 60% yield.

  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 mixed with propylene glycol monomethyl ether An ArF resist composition solution was prepared by dissolving in 533 parts of acetate.

Example 2 (Evaluation of composition for resist underlayer film)
The polymer cyclohexanone solution obtained in Example 1 was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resist underlayer film composition. Subsequently, performance evaluation was performed about this composition. The evaluation results are shown in Table 1.

Comparative Example 1
A commercially available ethyl lactate solution of novolak resin was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resist underlayer film composition. Subsequently, performance evaluation was performed about this composition. The pattern shape was evaluated by forming a positive resist pattern for ArF. The evaluation results are shown in Table 1.

Comparative Example 2
A positive resist pattern for ArF was formed without using the resist underlayer film composition, and performance evaluation was performed. The evaluation results are shown in Table 1.

  Since the resist underlayer film composition of the present invention has a high antireflection effect and is unlikely to cause intermixing with the resist film, the resolution, pattern shape, etc., in cooperation with various positive and negative resist compositions. An excellent resist pattern can be provided. Furthermore, the via embedding property in the dual damascene process is good. Therefore, each resist underlayer film composition of the present invention contributes particularly to the production of highly integrated circuits.

Claims (6)

A resist underlayer film composition containing a polymer having a structural unit represented by the following formula (1 ) .

In [Equation (1), ^{R 1} is a divalent aromatic group. ] The composition for resist underlayer films containing the polymer which has a structural unit represented by following formula ( 2).

[In Formula (2), R ² and R ³ are each independently a divalent aromatic group, and A represents a divalent organic group. ] The composition for a resist underlayer film according to claim 1 or 2 , wherein the polymer has a polystyrene-reduced weight average molecular weight of 500 to 10,000 as measured by gel permeation chromatography. Furthermore, the composition for resist underlayer films in any one of Claims 1-3 containing a solvent. Furthermore, the composition for resist underlayer films in any one of Claims 1-4 containing an acid generator. Furthermore, the composition for resist underlayer films in any one of Claims 1-5 containing a crosslinking agent.