JP5125825B2 - Underlayer film forming composition for multilayer resist process - Google Patents

Description

  The present invention relates to an underlayer film forming composition for a multilayer resist process, and more particularly to an underlayer film forming composition for a multilayer resist process capable of forming a resist underlayer film having excellent antireflection performance.

  In a method for manufacturing an integrated circuit element, a multi-layer resist process is used in order to obtain a higher degree of integration, and a reduction in processing size is achieved. In this process, first, a liquid underlayer film forming composition is applied on a substrate and then cured to form a resist underlayer film. Next, a liquid photoresist composition is applied to the formed resist underlayer film and prebaked to form a resist film. Next, the mask pattern is transferred by a reduction projection exposure apparatus (stepper) and developed with an appropriate developer to form a photoresist pattern. Subsequently, dry etching is performed to transfer the photoresist pattern to the resist underlayer film. Finally, the pattern of the resist underlayer film is transferred to the substrate by dry etching. As described above, a substrate on which a desired pattern is formed can be obtained. Note that the case of using one type of resist underlayer film is sometimes referred to as a two-layer resist process, and the case of using two types of resist underlayer films is sometimes referred to as a three-layer resist process.

  Generally, the resist underlayer film has a function as an antireflection film that absorbs radiation reflected from the substrate, and a material having a high carbon content is used. This is because when a material having a high carbon content is used for the resist underlayer film, the etching selectivity at the time of substrate processing is improved, and the pattern can be transferred more accurately. As such a material having a high carbon content, a resist underlayer film using a novolak resin is disclosed (for example, see Patent Documents 1 and 2). Further, it is disclosed that a resist underlayer film using a composition containing a polymer having an acenaphthylene skeleton also exhibits good characteristics (see, for example, Patent Document 3).

International Publication No. 2007/055147 Pamphlet JP 2001-40293 A JP 2000-143937 A

  In general, it is known that a resist underlayer film composed mainly of a novolak resin has a low refractive index and a high extinction coefficient at the wavelength of ArF excimer laser (193 nm). Further, the resist film for ArF excimer laser has a high refractive index (n ≧ 1.65) and a low extinction coefficient (k ≦ 0.1). Therefore, in order to improve the antireflection performance of the resist underlayer film, it is preferable to increase the refractive index (n ≧ 1.40) and set the extinction coefficient to a range of 0.20 to 0.40.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to provide a lower layer film for a multilayer resist process capable of forming a resist lower layer film having excellent antireflection performance. It is to provide a forming composition.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be achieved by containing a novolak resin obtained by condensing predetermined components. It came to be completed.

  That is, according to the present invention, the following underlayer film forming composition for a multilayer resist process is provided.

  [1] (A) a novolak resin and (B) an organic solvent, wherein the (A) novolac resin is (a1) 1 to 99% by mass of a compound having two or more phenolic hydroxyl groups in the molecule. (A2) 1 to 10% by mass of naphthol, (a3) 0 to 98% by mass of a compound having a phenolic hydroxyl group (excluding the (a1) compound and (a2) naphthol) (provided that (a1) + (A2) + (a3) = 100% by mass), and (a4) an aldehyde, a resin obtained by condensing an underlayer film forming composition for a multilayer resist process.

  [2] The underlayer film forming composition for a multilayer resist process according to [1], wherein the compound (a1) is at least one compound selected from the group consisting of a dihydroxybenzene derivative, a dihydroxynaphthalene derivative, and a dihydroxyanthracene derivative. .

  [3] The above-mentioned [1] or [2], wherein the (A) novolak resin has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation column chromatography of 1,000 to 5,000. An underlayer film forming composition for a multilayer resist process.

  The underlayer film forming composition for a multilayer resist process of the present invention has an effect that a resist underlayer film excellent in antireflection ability can be formed.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

I. Underlayer film forming composition for multilayer resist process The underlayer film forming composition for multilayer resist process of the present invention (hereinafter referred to as “underlayer film forming composition”) comprises (A) a novolak resin, (B) an organic solvent, It contains. (A) Since it contains a novolac resin, the etching selectivity at the time of substrate processing is improved, the pattern can be transferred more accurately, and a resist underlayer film excellent in antireflection ability can be formed. .

1 (A) novolak resin (A) novolak resin is (a1) 1 to 99% by mass of a compound having two or more phenolic hydroxyl groups in the molecule (hereinafter referred to as “(a1) compound”), (a2) naphthol 1 to 10% by mass of (a3) a compound having a phenolic hydroxyl group (however, excluding (a1) compound and (a2) naphthol) (hereinafter referred to as “(a3) compound”) , (A1) + (a2) + (a3) = 100% by mass), and (a4) an aldehyde.

  The content of the (A) novolak resin with respect to the lower layer film-forming composition is preferably 8 to 30% by mass, and more preferably 10 to 15% by mass. (A) If the content of the novolak resin is less than 8% by mass, a resist underlayer film having desired properties may not be formed. On the other hand, if it exceeds 30% by mass, the flatness during coating and film formation may be poor.

(1) Component (i) (a1) Compound (a1) The compound is a compound having two or more phenolic hydroxyl groups in the molecule, and is selected from the group consisting of dihydroxybenzene derivatives, dihydroxynaphthalene derivatives and dihydroxyanthracene derivatives. Preferably it is at least one compound.

  Specific examples of the compound (a1) include pyrogallol, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, tris (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl)- 1-phenylethane, tris (4-hydroxyphenyl) ethane, 1,3-bis (1- (4-hydroxyphenyl) -1-methylethyl) benzene, 1,4-bis (1- (4-hydroxyphenyl) -1-methylethyl) benzene, 4,6-bis (1- (4-hydroxyphenyl) -1-methylethyl) -1,3-dihydroxybenzene, 1,1-bis (4-hydroxyphenyl) -1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethane, 1,1,2,2-tetra (4-hydride) Kishifeniru) ethane, compounds such as bisphenol A; catechol, resorcinol, dihydroxybenzene derivatives such as 1,4-hydroquinone;

  1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2 Dihydroxynaphthalene derivatives such as 1,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene; 1,2-dihydroxyanthracene, 1,3-dihydroxyanthracene, 1,4-dihydroxyanthracene, 1,5- Dihydroxyanthracene, 1,6-dihydroxyanthracene, 1,7-dihydroxyanthracene, 1,8-dihydroxyanthracene, 1,9-dihydroxyanthracene, 1,10-dihydroxyanthracene, 2,3 Dihydroxyanthracene, 2,4-dihydroxyanthracene, 2,5-dihydroxyanthracene, 2,6-dihydroxyanthracene, 2,7-dihydroxyanthracene, 2,8-dihydroxyanthracene, 2,9-dihydroxyanthracene, 2,10-dihydroxy And dihydroxyanthracene derivatives such as anthracene and 9,10-dihydroxyanthracene. Among these, 1,4-dihydroxyanthracene, 1,5-dihydroxyanthracene, 1,6-dihydroxyanthracene, 2,6-dihydroxyanthracene, 2,7-dihydroxyanthracene, and 9,10-dihydroxyanthracene are preferable. In addition, the compound (a1) may be used alone or in combination of two or more.

  The amount of the (a1) compound used is preferably 1 to 99% by mass and 90 to 99% by mass with respect to 100% by mass in total of the (a1) compound, (a2) naphthol and (a3) compound. Is more preferable, and it is especially preferable that it is 95-99 mass%.

(Ii) (a2) Naphthol (a2) As naphthol, specifically, 1-naphthol and 2-naphthol can be used.

  The amount of (a2) naphthol used is preferably 1 to 10% by mass, and preferably 1 to 7% by mass, based on a total of 100% by mass of the (a1) compound, (a2) naphthol and (a3) compound. Is more preferable, and it is especially preferable that it is 1-5 mass%.

(Iii) (a3) Compound (a3) The compound is a compound having a phenolic hydroxyl group excluding (a1) compound and (a2) naphthol. Specifically, phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3- Xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, Examples include o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol, o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene. Among these, o-cresol, m-cresol, p-cresol, o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene are preferable. In addition, the (a3) compound may be used alone or in combination of two or more.

  The amount of the (a3) compound used is preferably 98% by mass or less, more preferably 20% by mass or less, with respect to 100% by mass in total of the (a1) compound, (a2) naphthol and (a3) compound. It is preferably 1 to 5% by mass. In addition, when the (a3) compound is contained as a constituent component, the lower limit is not particularly limited, but is usually 1% by mass or more.

(Iv) (a4) Aldehyde (a4) As aldehyde, specifically, saturated aliphatic aldehydes such as formaldehyde, paraformaldehyde, acetaldehyde and propylaldehyde; unsaturated aliphatic aldehydes such as acrolein and methacrolein; furfural and the like Heterocyclic aldehydes; aromatic aldehydes such as benzaldehyde, naphthylaldehyde, anthraldehyde, and the like. Among these, formaldehyde, paraformaldehyde, and furfural are preferable. In addition, (a4) aldehyde may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The amount of (a4) aldehyde used is preferably 50 to 500% by mass and preferably 60 to 120% by mass with respect to 100% by mass in total of the (a1) compound, (a2) naphthol and (a3) compound. Is more preferable, and it is especially preferable that it is 70-100 mass%.

(V) (b) Other compounds (A) The novolak resin is obtained by condensing other compounds (hereinafter referred to as “other compounds”) in addition to the aforementioned (a1) compound to (a4) aldehyde. Resin may be used. Other compounds can modify the (A) novolac resin by substituting the aromatic skeleton present in the (A) novolak resin.

  Examples of other compounds include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-acetoxystyrene, m-acetoxystyrene, p-acetoxystyrene, and pt-butoxy. Styrene derivatives such as styrene; vinyl carboxylates such as vinyl acetate, vinyl propionate and vinyl caproate; vinyl cyanide compounds such as (meth) acrylonitrile and α-chloroacrylonitrile; methyl (meth) acrylate, ethyl (meth) acrylate Unsaturated carboxylic acid ester compounds such as n-propyl (meth) acrylate, n-butyl (meth) acrylate, n-hexyl (meth) acrylate and glycidyl (meth) acrylate;

  Unsaturated group-containing unsaturated carboxylic acid ester compounds such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, vinyl (meth) acrylate, dimethylvinylmethacryloyloxymethylsilane; 2-chloroethyl vinyl ether, chloroacetic acid Halogen-containing vinyl compounds such as vinyl and allyl chloroacetate; hydroxyl-containing vinyl compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and (meth) allyl alcohol;

  Amide group-containing vinyl compounds such as (meth) acrylamide and crotonic acid amide; Carboxyl group-containing vinyl compounds such as 2-methacryloyloxyethylsuccinic acid and 2-methacryloyloxyethylmaleic acid; benzene, naphthalene, anthracene, phenanthrene, acenaphthene Unsubstituted aromatic hydrocarbon compounds such as

  Alkyl-substituted aromatic hydrocarbon compounds such as toluene, m-xylene, p-xylene and 1-methylnaphthalene; carboxyl group-substituted aromatic hydrocarbon compounds such as benzoic acid, 1-naphthalenecarboxylic acid and 9-anthracenecarboxylic acid; aniline Amino group-substituted aromatic hydrocarbon compounds such as chlorobenzene, bromobenzene, and other halogenated aromatic hydrocarbon compounds;

  Butadiene, vinylbenzene, divinylbenzene, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorborna-2-ene, α-pinene, β-pinene, limonene, 5-vinylnorbornadiene, 1-vinylnaphthalene, 2- Examples thereof include vinyl compounds such as vinyl naphthalene, 9-vinyl anthracene and 9-vinyl carbazole. Among these, divinylbenzene, dicyclopentadiene, 5-vinylnorborna-2-ene, 1-vinylnaphthalene, and 2-vinylnaphthalene are preferable. In addition, another compound may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The usage-amount of another compound is 1-50 mass parts normally with respect to a total of 100 mass parts of (a1) compound, (a2) naphthol, and (a3) compound, Preferably it is 1-30 mass parts. More preferably, it is 1-10 mass parts.

(2) (A) Preparation method of novolak resin (A) The novolak resin can be prepared, for example, by condensing (a1) compound to (a4) aldehyde in the presence of an acid catalyst. Moreover, when condensing (a1) compound-(a4) aldehyde, you may add and condense another compound.

  Specific examples of the acid catalyst include mineral acids such as sulfuric acid, phosphoric acid and perchloric acid; organic sulfonic acids such as p-toluenesulfonic acid; carboxylic acids such as formic acid and oxalic acid. Although the usage-amount of an acid catalyst changes with kinds of acid catalyst to be used, it is 0.001-30 mass parts normally with respect to a total of 100 mass parts of (a1) compound, (a2) naphthol, and (a3) compound. Preferably, it is 0.01-10 mass parts, More preferably, it is 0.1-5 mass parts.

  As conditions for the condensation reaction, the reaction temperature is usually 40 to 200 ° C, preferably 60 to 150 ° C, and more preferably 70 to 100 ° C. Moreover, although reaction time changes with reaction temperature, it is 30 minutes-72 hours normally, it is preferable that it is 1 to 24 hours, and it is still more preferable that it is 2 to 10 hours.

(3) (A) Physical property value of novolak resin (A) Polystyrene-converted weight average molecular weight (hereinafter referred to as “Mw”) measured by gel permeation column chromatography of novolak resin is 1,000-5. Is preferably 1,000, 3,000, more preferably 1,000 to 3,000, and particularly preferably 1,000 to 2,000.

2 (B) Organic solvent (B) The organic solvent is not particularly limited as long as it can dissolve the (A) novolak resin. Specifically, 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 monomethyl ether acetate, ethylene glycol mono Ethylene glycol monoalkyl ether acetates such as ethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di- Diethylene glycol such as n-butyl ether Le dialkyl ethers; triethylene glycol dimethyl ether, triethylene glycol dialkyl ethers such as 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 dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n -Propylene glycol dialkyl ethers such as propyl ether and propylene glycol di-n-butyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate Propylene glycol such as Roh alkyl ether acetates;

  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-formate Butyl, i-butyl formate, n-amyl formate, i-amyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-acetate -Amyl, n-hexyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate Aliphatic carboxylic acid esters such as i-propyl butyrate, n-butyl butyrate and 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; N-methylformamide, N , N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone and other amides; γ-butyrolactone and other lactones.

  Among these, propylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, γ-butyrolactone and the like are preferable. . In addition, (B) organic solvent may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  (B) The amount of the organic solvent used is preferably such that the solid content concentration of the lower layer film-forming composition is 5 to 80% by mass, more preferably 5 to 40% by mass, It is particularly preferable that the amount is 10 to 30% by mass.

3 Other components In the lower layer film-forming composition, other components such as (C) acid generator, (D) cross-linking agent, and (E) additive, etc., as long as desired effects are not impaired. It is preferable to contain.

(1) (C) Acid generator (C) An acid generator is a component which generates an acid by exposure or heating. Hereinafter, in this specification, an acid generator that generates an acid upon exposure is referred to as a “photoacid generator”, and an acid generator that generates an acid upon heating is referred to as a “thermal acid generator”. Moreover, (C) A photo-acid generator and a thermal acid generator can also be used together as an acid generator.

(I) Photoacid generator As the photoacid generator, specifically, 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-butylpheny ) Iodonium 10-camphorsulfonate, bis (4-t- butylphenyl) iodonium naphthalene sulfonate, 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 trifluoro Lome Sulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldiethyl Sulfonium trifluoromethanesulfonate,

  1- (4-hydroxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (4- (1-methoxyethoxy) naphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4- (2-methoxyethoxy) naphthalene 1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothio Phenium trifluoromethanesulfonate, 1- (4-n-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate,

  1- (4-i-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, (4-t-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4- (2-tetrahydrofuranyloxy) naphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4- (2-Tetrahydropyranyloxy) naphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-benzyloxy) tetrahydrothiophenium trifluoro Methanesulfonate, 1- (naphthyl acetamide methyl) onium salt photoacid generators such as tetrahydrothiophenium trifluoromethanesulfonate;

  Halogen-containing compound-based photoacid generators such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine; 2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,3,4-naphthoquinonediazide-4-sulfonic acid ester of 2,3,4,4′-tetrahydroxybenzophenone or 1, Diazoketone compound photoacid generators such as 2-naphthoquinonediazide-5-sulfonic acid ester; sulfone compound photoacid generators such as 4-trisphenacylsulfone, mesitylphenacylsulfone, and bis (phenylsulfonyl) methane Benzoin tosylate, pyrogallol Lith (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide Examples include sulfonic acid compound photoacid generators such as trifluoromethanesulfonate and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate.

  Among these, 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-butyl) Phenyl) iodonium 10-camphorsulfonate, bis (4-tert-butylphenyl) iodoni Arm naphthalene sulfonate, and the like are preferable. In addition, a photo-acid generator may be used individually by 1 type, and 2 or more types may be mixed and used for it.

(Ii) Thermal acid generator Specific examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl sulfonates. Can do. In addition, a thermal acid generator may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The content of (C) acid generator is preferably 30 parts by mass or less, more preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass per 100 parts by mass of (A) novolak resin. It is particularly preferred. When the underlayer film forming composition contains (C) an acid generator, a crosslinking reaction can be effectively caused between the molecular chains of the (A) novolak resin at a relatively low temperature including normal temperature.

(2) (D) Crosslinking agent (D) The crosslinking agent intermixes between a resist underlayer film obtained by curing an underlayer film forming composition and a resist film formed on the resist underlayer film. It is a component having an action of preventing and further preventing the occurrence of cracks in the resist underlayer film. As such a crosslinking agent, polynuclear phenols and various commercially available curing agents can be used. Moreover, these can also be used together.

(I) Polynuclear phenols Specific examples of polynuclear phenols include binuclear phenols such as 4,4′-biphenyldiol, 4,4′-methylenebisphenol, 4,4′-ethylidenebisphenol, and bisphenol A; 4 , 4 ′, 4 ″ -methylidenetrisphenol, trinuclear phenols such as 4,4 ′-(1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol And polyphenols such as novolak. Among these, 4,4 ′-(1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol, novolak, and the like are preferable. In addition, polynuclear phenols may be used individually by 1 type, and may mix and use 2 or more types.

(Ii) Curing agent As commercially available curing agents, specifically, 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 3,4-tolylene diisocyanate, 3,5-tolylene diisocyanate Diisocyanates such as narate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate; the following trade names: “Epicoat 812”, 815, 826, 828, 834, 836, 871, 1001, 1004, 1007, 1009, 1009 (above, manufactured by Yuka Shell Epoxy), "Araldite 6600", 6700, 6800, 502, 6071, 6084, 6097, 6099 (above, manufactured by Ciba Geigy), “DER331”, 33 Epoxy compounds such as 333, 661, 644, 667 (manufactured by Dow Chemical Co., Ltd.); “Cymel 300”, 301, 303, 350, 370, 771, 325, 327 703, 712, 701, 272, 202, "My Coat 506", 508 (above, manufactured by Mitsui Cyanamid Co., Ltd.) and the like; "Cymel 1123", 1123-10, 1128, “My Coat 102”, 105, 106, 130 (above, Mitsui Cyanamid Co., Ltd.) and other benzoguanamine-based curing agents; “Cymel 1170”, 1172 (above, Mitsui Cyanamid Co., Ltd.), “Nicarac N -2702 "(manufactured by Sanwa Chemical Co., Ltd.) and the like. Among these, melamine type curing agents, glycoluril type curing agents and the like are preferable. In addition, a hardening | curing agent may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  (D) The content of the crosslinking agent is preferably 30 parts by mass or less and more preferably 10 parts by mass or less per 100 parts by mass of (A) novolak resin.

(3) (E) Additive (E) Additive is a resist underlayer film and a resist film except for (C) acid generator and (D) cross-linking agent among the components contained in the underlayer film forming composition. It is a component which has the effect | action of preventing the intermixing between and improving the applicability | paintability of a lower layer film forming composition. Examples of (E) additives include binder resins, radiation absorbers, surfactants, storage stabilizers, antifoaming agents, and adhesion aids.

(I) Binder resin Various thermoplastic resins and thermosetting resins can be used as the binder resin. Specific examples of the thermoplastic resin include polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-heptene, poly-1-octene, poly-1-decene, Α-olefin polymers such as poly-1-dodecene, poly-1-tetradecene, poly-1-hexadecene, poly-1-octadecene, and polyvinylcycloalkane; poly-1,4-pentadiene, poly-1,4 Non-conjugated diene polymers such as hexadiene and poly-1,5-hexadiene; α, β-unsaturated aldehyde polymers; poly (methyl vinyl ketone), poly (aromatic vinyl ketone), poly (cyclic vinyl ketone) ), Etc .; (meth) acrylic acid, α-chloroacrylic acid, (meth) acrylate, (meth) acrylic acid Polymers of α, β-unsaturated carboxylic acids or derivatives thereof such as tellurium and (meth) acrylic acid halides; α, β-unsaturated polymers of poly (meth) acrylic anhydride and maleic anhydride Polymers of saturated carboxylic acid anhydrides; Polymers of unsaturated polybasic carboxylic acid esters such as methylenemalonic acid diester and itaconic acid diester;

  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; Polyamides such as nylon 66 and nylon 1 to nylon 12; Polyesters such as aliphatic polyester, aromatic polyester, alicyclic polyester, and polycarbonate; Polyureas; Polysulfones; Polyazines; Polyamines Polyaromatic ketones, polyimides, polybenzimidazoles, polybenzoxazoles, polybenzothiazoles, polyaminotriazoles, polyoxadiazoles, polypyrazoles, polytetrazoles, polyquinoxalines, polytriazines Polybenzoxazinones; polyquinolines; polyanthrazolins and the like.

  The thermosetting resin is a component that is cured by heating and becomes insoluble in a solvent, and has an action of preventing intermixing between the resist underlayer film and the resist film formed thereon. Specific examples of thermosetting resins include thermosetting acrylic resins, phenol resins, urea resins, melamine resins, amino resins, aromatic hydrocarbon resins, epoxy resins, alkyd resins. Etc. Among these, urea resins, melamine resins, aromatic hydrocarbon resins and the like are preferable.

  Binder resin may be used individually by 1 type, and may mix and use 2 or more types. The content of the binder resin is preferably 10 parts by mass or less, more preferably 5 parts by mass or less per 100 parts by mass of (A) novolac resin.

(Ii) Radiation absorbers Examples of radiation absorbers include oil-soluble dyes, disperse dyes, basic dyes, methine dyes, pyrazole dyes, imidazole dyes, hydroxyazo dyes, and the like; bixin derivatives, norbixin , Stilbene, 4,4′-diaminostilbene derivatives, coumarin derivatives, pyrazoline derivatives and other fluorescent whitening agents; hydroxyazo dyes, trade names “Tinuvin 234”, 1130 (above, manufactured by Ciba Geigy) Agents: aromatic compounds such as anthracene derivatives and anthraquinone derivatives. In addition, a radiation absorber may be used individually by 1 type, and may mix and use 2 or more types. The content of the radiation absorber is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of (A) novolac resin.

(Iii) Surfactant A 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”, and 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 & Chemicals, Inc.), "Florard FC430", FC431, FC135, FC93 (Sumitomo 3M), "Asahi Guard AG710", "Surflon S382", SC101, SC102, SC103 SC104, SC105, and SC106 (above, manufactured by Asahi Glass Co., Ltd.). In addition, surfactant may be used individually by 1 type and may be used in mixture of 2 or more types. The content of the surfactant is preferably 5 parts by mass or less and more preferably 1 part by mass or less per 100 parts by mass of (A) novolak resin.

II. Method for Forming Resist Pattern Using Underlayer Film Forming Composition A resist pattern using the underlayer film forming composition of the present invention can be formed, for example, as follows. First, after applying an underlayer film forming composition on a substrate, the coating film is cured to form a resist underlayer film. Next, after applying a resist composition solution on the resist underlayer film, the coating film is pre-baked to form a resist film. The formed resist film is selectively exposed through a photomask and then developed. Finally, a resist pattern can be formed by etching the resist underlayer film.

1 Formation of resist underlayer film The resist underlayer film can be formed by applying a lower layer film forming composition on a substrate and then curing the coating film. As the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used. Moreover, application | coating of a lower layer film formation composition can be implemented suitably by methods, such as spin coating, cast coating, and roll coating. Furthermore, the conditions for curing the coating film can be appropriately selected according to the underlayer film forming composition, and examples thereof include exposure and / or heating conditions.

  The radiation used for exposure is from visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ rays, molecular beams, ion beams, etc., depending on the type of photoacid generator contained in the underlayer film forming composition. Appropriately selected. When the underlayer film forming composition contains a photoacid generator and is exposed, the coating film can be effectively cured even at room temperature. Moreover, it is preferable that heating temperature is about 90-350 degreeC, and it is still more preferable that it is about 200-300 degreeC. When the underlayer film forming composition contains a thermal acid generator, for example, the coating film can be effectively cured even at a temperature of about 90 to 150 ° C. In addition, it is preferable that the film thickness of a resist underlayer film is 0.1-5 micrometers.

2 Formation of resist film After applying the resist composition solution on the resist underlayer film so that the resist film has a predetermined thickness, pre-baking is performed to volatilize the solvent in the film to form a resist film. be able to.

  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 and a crosslinking agent. A negative resist composition comprising an agent. The resist composition solution preferably has a solid content concentration of about 5 to 50% by mass, and is used after being filtered through a filter having a pore diameter of about 0.2 μm, for example, before being applied on the resist underlayer film. A commercially available resist composition solution can also be used as it is.

  The pre-baking temperature is appropriately adjusted according to the type of the resist composition, but is preferably about 30 to 200 ° C., more preferably about 50 to 150 ° C.

3. Exposure As radiation used for exposure, visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ rays, molecular beams, ion beams, etc., depending on the type of photoacid generator contained in the resist composition It can be used by appropriately selecting from. Among these, far ultraviolet rays are preferable, and KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (wavelength 157 nm), Kr ₂ excimer laser (wavelength 147 nm), ArKr excimer laser (wavelength 134 nm), pole Ultraviolet rays (wavelength 13 nm or the like) are more preferable.

4 Development The resist film after exposure is developed, washed and dried. In order to improve resolution, pattern profile, developability, etc., it is also preferable to perform post-baking after exposure and before development.

  The developer is appropriately selected according to the type of resist composition used. When using a positive type chemically amplified resist composition or a positive type resist composition containing an alkali-soluble resin, examples of the developer include 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, 1,5-diazabicyclo [4.3.0] -5-nonene and the like are used. In addition, an appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, and a surfactant can be added to these alkaline aqueous solutions.

5 Etching After drying, for example, dry etching of the resist underlayer film can be performed using gas plasma such as oxygen plasma to form a resist pattern for processing a predetermined substrate.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Measurement of weight average molecular weight (Mw)]: Using a GPC column (G2000HXL: 2, G3000HXL: 1) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C. The analysis was performed by gel permeation column chromatography under the analysis conditions, and the value was calculated as a value in terms of polystyrene.

  [Evaluation of pattern shape]: The pattern shape of the formed positive resist pattern is observed using a scanning electron microscope, and the case where the pattern shape is rectangular is evaluated as “◯”, and the case where the pattern shape is not rectangular is “ “×”.

  [Evaluation of standing wave prevention effect]: The formed positive resist pattern was observed using a scanning electron microscope, and “○” was evaluated when there was no standing wave, and “×” when there was a standing wave. ".

  [Values of refractive index n and extinction coefficient k with respect to light having a wavelength of 193 nm]: After a lower film forming composition was spin-coated on a silicon wafer having a diameter of 8 inches, it was heated at 180 ° C. for 60 seconds, and further at 300 ° C. for 60 seconds. A 300 nm-thick resist underlayer film is formed by heating on a hot plate, and the refractive index n and extinction coefficient k for light with a wavelength of 193 nm are measured using a spectroscopic ellipsometer (trade name “VUV-VASE”, Woollam). ).

[Evaluation of etching resistance]: After applying the underlayer film forming composition by spin coating to form a resist underlayer film, CF ₄ / Ar / O was used by using an etching apparatus “EXAM” (manufactured by Shinko Seiki Co., Ltd.). ₂ (CF ₄ : 40 mL / min, Ar: 20 mL / min, O ₂ : 5 mL / min; pressure: 20 Pa; RF power: 200 W; processing time: 40 seconds; temperature: 15 ° C.). The film thickness of the resist underlayer film before and after the etching treatment was measured, the etching rate was calculated, and the etching resistance was evaluated. The etching rate was calculated by forming a reference resist underlayer film using a resist underlayer film forming composition (product name “NFC1400”) manufactured by JSR. The evaluation criteria are as follows.
◎: When the etching rate is −10% or less compared to the reference resist underlayer film ○: When the etching rate is over −10% and 0% or less compared to the reference resist underlayer film Δ: Compared to the reference resist underlayer film When the etching rate is over 0% and + 10% or less ×: When the etching rate is over + 10% compared to the reference resist underlayer film

  [Evaluation of via embedding properties]: After spin coating the underlayer film forming composition on a tetraethylorthosilicate (TEOS) substrate processed to a via size of 140 nm, a via pitch of 1H / 1.2S, and a depth of 1000 nm, 180 Heating was performed on a hot plate at 60 ° C. for 60 seconds and then at 300 ° C. for 60 seconds to form a resist underlayer film having a thickness of 300 nm in the via hole and on the surface of the TEOS substrate. The underlayer film forming composition was observed with a scanning electron microscope to see if it was embedded in the via hole. When the composition penetrated well into the via hole and was embedded in the via hole, it was evaluated as “◯” and embedded in the via hole. The case where it was not evaluated was evaluated as “×”.

(Synthesis Example 1)
In a separable flask equipped with a reflux tube, 8-methyl-8-t-butoxycarbonylmethoxycarbonyltetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-3-ene (hereinafter referred to as monomer (i)) 29 parts, 8-methyl-8-hydroxytetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-3-ene (hereinafter referred to as “monomer (b)”) 10 parts, maleic anhydride (hereinafter referred to as “monomer (c)”) 18 parts, 2,5-dimethyl Charge 4 parts of 2,5-hexanediol diacrylate, 1 part of t-dodecyl mercaptan, 4 parts of azobisisobutyronitrile, and 60 parts of 1,2-diethoxyethane, and polymerize at 70 ° C. for 6 hours with stirring. did. Thereafter, the reaction solution was poured into a large amount of a mixed solvent of n-hexane / i-propyl alcohol (mass ratio = 1/1) to solidify the resin in the reaction solution. The coagulated resin was washed several times with a mixed solvent and then vacuum-dried to prepare a resin having the following structure (yield 60%). The resin had a molar ratio ((a) :( b) :( c)) of 64:18:18 and Mw of 27,000.

  Thereafter, 80 parts of the resulting resin, 1.5 parts of 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, and 0.04 part of tri-n-octylamine are propylene. A resist composition for ArF excimer laser (hereinafter referred to as “resist composition”) was prepared by dissolving in 533 parts of glycol monomethyl ether acetate.

(Synthesis Example 2)
A separable flask equipped with a thermometer is charged with 63 parts of 1,5-dihydroxynaphthalene, 7 parts of 1-naphthol, 30 parts of formalin, 300 parts of methyl isobutyl ketone, and 1 part of p-toluenesulfonic acid in a nitrogen atmosphere. The mixture was polymerized at 80 ° C. for 7 hours with stirring. Thereafter, the reaction solution was washed with a large amount of water, and the solvent was distilled off to synthesize (A) novolak resin (1) having an Mw of 1,500.

(Synthesis Examples 3 to 12)
(A) Novolak resins (2) to (8) and novolak resins (1) to (3) were synthesized in the same manner as in Synthesis Example 2 except that the compounds shown in Table 1 were used.

Example 1
10 parts of (A) novolak resin (1) synthesized in Synthesis Example 2 was dissolved in 90 parts of cyclohexanone, and then filtered through a membrane filter having a pore size of 0.1 μm to prepare an underlayer film forming composition (1). . The prepared underlayer film-forming composition (1) was spin-coated on a silicon wafer having a diameter of 8 inches, and then heated on a hot plate at 180 ° C. for 60 seconds and further at 300 ° C. for 60 seconds to obtain a film having a thickness of 300 nm. A resist underlayer film was formed. Thereafter, a three-layer resist process intermediate layer solution (trade name “NFC SOG04” manufactured by JSR Corporation) is spin-coated on the resist underlayer film, and then heated on a hot plate at 200 ° C. for 60 seconds and further at 300 ° C. for 60 seconds. To form an intermediate layer film having a thickness of 50 nm. Next, a solution of the resist composition synthesized in Synthesis Example 1 was spin-coated on this intermediate layer film, and pre-baked on a 130 ° C. hot plate for 90 seconds to form a 200 nm-thick photoresist film. Using an ArF excimer laser exposure apparatus (lens numerical aperture of 0.78, exposure wavelength of 193 nm) manufactured by NIKON, exposure was performed for the optimal exposure time through a mask pattern, and then post-baked on a 130 ° C. hot plate for 90 seconds. The film was developed at 25 ° C. for 1 minute using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38%. Thereafter, it was washed with water and dried to form a positive resist pattern. The evaluation of the pattern shape of the formed positive resist pattern is “◯”, the evaluation of the standing wave prevention effect is “◯”, the refractive index value is 1.42, and the extinction coefficient value is 0. 36. Moreover, the evaluation of the etching resistance of the resist underlayer film was “◎”, and the evaluation of the via embedding property of the underlayer film forming composition (1) was “◯”.

(Examples 2-8, Comparative Examples 1-3)
(A) In the same manner as in Example 1, except that (A) novolak resins (2) to (8) and novolak resins (1) to (3) were used instead of the novolak resin (1), the lower layer Film-forming compositions (2) to (11) were prepared to form a positive resist pattern. The evaluation results and physical property values are shown in Table 2.

  From the results described in Table 2, (A) the resist underlayer film formed by the underlayer film-forming composition of the present invention containing a novolak resin has good filling performance in via holes, high etching resistance, and an antireflection film. It can be seen that it has an excellent antireflection effect.

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

Claims (3)

(A) a novolac resin;
(B) an organic solvent,
The (A) novolac resin is
(A1) 1 to 99% by mass of a compound having two or more phenolic hydroxyl groups in the molecule;
(A2) 1-10% by mass of naphthol,
(A3) 0 to 98% by mass (provided that (a1) + (a2) + (a3) = 100% by mass) a compound having a phenolic hydroxyl group (excluding the compound (a1) and the above (a2) naphthol) And (a4) an underlayer film forming composition for a multilayer resist process, which is a resin obtained by condensing aldehyde.   2. The underlayer film forming composition for a multilayer resist process according to claim 1, wherein the compound (a1) is at least one compound selected from the group consisting of a dihydroxybenzene derivative, a dihydroxynaphthalene derivative, and a dihydroxyanthracene derivative.   The lower layer for a multilayer resist process according to claim 1 or 2, wherein the (A) novolak resin has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation column chromatography of 1,000 to 5,000. Film-forming composition.