JP2007272168A - Composition for resist underlayer film and resist underlayer film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for a resist underlayer film that can reduce trailing in a resist pattern and improve a shape of the pattern, and to provide a resist underlayer film using the composition. <P>SOLUTION: The composition for a resist underlayer film contains (A) a siloxane compound having a mass average molecular weight of 3,000 or smaller and (B) a siloxane polymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resist underlayer film composition used for a resist underlayer film used as an antireflection film when forming a resist pattern on a substrate, and a resist underlayer film using the same.

In the manufacture of semiconductor elements, pattern formation on a substrate is performed by a lithography process.
In recent years, as the integration of semiconductor elements on a circuit board has progressed, standing waves generated during the exposure process have caused variations in the dimensions of the pattern. As a method for suppressing this standing wave, a method of adding a light-absorbing agent to the resist composition or laying an antireflection film on the upper surface of the formed resist layer or the lower layer of the resist layer has been proposed.

  In order to form a finer pattern, it is required to reduce the thickness of the antireflection film and the resist layer. However, since it is difficult to perform accurate etching as the resist layer is thinned, it is difficult to process the substrate with high accuracy. Therefore, a resist underlayer film (hard mask) and / or an organic bottom layer having a function as an antireflection film is formed between a film to be processed such as a substrate to be processed and a resist layer to form a substrate, A process of dry etching a film to be processed such as an oxide film or an interlayer insulating film is performed.

It has been proposed to use a silicon-based material for the resist underlayer film composition because of the problem of the etching selectivity with the resist layer (see, for example, Patent Documents 1 and 2).
JP 2004-310019 A JP-A-2005-18054

  However, the resist underlayer film materials disclosed in Patent Documents 1 and 2 have a problem that tailing occurs in the resist pattern formed on the resist underlayer film formed from the resist underlayer film material. . When such tailing occurs, there arises a problem that the pattern cannot be transferred to a desired shape when the resist underlayer film is etched.

  In view of the above problems, the present invention provides a resist underlayer film composition capable of reducing the tailing of a resist pattern and improving the shape of the pattern, and a resist underlayer film using the same. Objective.

The present invention provides a resist underlayer film composition containing (A) a siloxane compound having a mass average molecular weight of 3000 or less and (B) a siloxane polymer.
Moreover, the resist underlayer film obtained by apply | coating the said composition for resist underlayer films and baking at predetermined temperature is provided.

  According to the present invention, the tailing of the resist pattern formed on the resist underlayer film is reduced by containing (A) a siloxane compound having a mass average molecular weight of 3000 or less as the polymer in the resist underlayer film. At the same time, the pattern shape can be improved.

  Hereinafter, embodiments of the present invention will be described in detail. The resist underlayer film composition according to the present invention comprises (B) a siloxane polymer (hereinafter also referred to as component (B)) and (A) a siloxane compound having a mass average molecular weight of 3000 or less (hereinafter referred to as (A). Component)).

[(A) Siloxane compound]
The resist underlayer film composition according to the present invention contains (A) a siloxane compound. This (A) siloxane copolymer has a mass average molecular weight of 3000 or less. By setting the mass average molecular weight in such a range, it is possible to reduce the tailing of the resist pattern formed on the resist underlayer film and to improve the pattern shape.

  As said (A) siloxane type compound, what has a structure of either a ladder-like structure, a cyclic structure, or a cage structure as shown by the following general formula (a-1) and (a-2) is preferable. It is mentioned as a thing.

[Wherein, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ are each independently a hydrogen atom, a hydroxyl group, an alkyl group, or an alkoxy group, and R ² are each independently linear or branched. Alternatively, it is a cyclic hydrocarbon group, and in (a-1), R ¹ and R ³ and / or R ⁴ and R ⁵ may be combined to form —O—, and m is from 1 to 8. Yes, n is 2 to 8. ]

Here, the “alkyl group” and “alkoxy group” of R ¹ , R ³ , R ⁴ , R ⁵ and R ⁶ are preferably those having 1 to 3 carbon atoms.
Examples of these alkyl groups include a methyl group, an ethyl group, a propyl group, and an isopropyl group.
Examples of these alkoxy groups include a methoxy group, an ethoxy group, and a propoxy group.
In the compounds of the general formulas (a-1) and (a-2), it is preferable that 25 mol% or more of the total of R ¹ , R ³ , R ⁴ and R ⁵ is a hydroxyl group.
Moreover, in the compound of general formula (a-3), it is preferable that 25 mol% or more of R ⁶ is a hydroxyl group.

Furthermore, the hydrocarbon group for R ² is preferably a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 18 carbon atoms or an aromatic hydrocarbon group. Examples of the linear or branched hydrocarbon group include methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, neopentyl group, hexyl group, octyl group, nonyl group, decyl group, and undecyl group. And alkyl groups such as dodecyl group; alkenyl groups such as vinyl group, allyl group and propenyl group; cyclic alkyl groups such as cyclopentyl group, cyclohexyl group, norbornyl group, norbornenyl group and adamantyl group; Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a methylphenyl group, an ethylphenyl group, a tolyl group, a chlorophenyl group, a bromophenyl group, and a fluorophenyl group; a benzyl group, a phenethyl group, and a naphthylmethyl group Aralkyl groups such as diphenylmethyl group, triphenylmethyl group, 1-methyl-1-phenylethyl group, and the like. These hydrocarbon groups may have a substituent, and examples of the substituent include a hydroxyl group and an alkoxy group having 1 to 3 carbon atoms.
Among these, preferred as R ² is a norbornyl group or a group represented by the following formula (a-4).
[Wherein p is 0 or 1, and q is 0 to 5. ]
In particular, the group represented by the formula (a-4) is excellent in compatibility with the later-described component (B) and the organic solvent, and is preferable.
Included in the siloxane compound represented by the formula (a-1) (a- 2), a group represented by the formula (a-4) is 10 mol% or more of ^{R 2,} more preferably at least 25 mol% It is preferable that In the siloxane compound represented by the formula (a-3), a group represented by the formula (a-4) is 12.5 mol% or more of ^{R 2,} includes more preferably more than 25 mol% It is preferable. By setting it to the above value or more, the compatibility of the (A) siloxane compound with the organic solvent can be particularly improved.

In the compound of the formula (a-1), R ¹ and R ³ and / or R ⁴ and R ⁵ may be combined to be —O—. In this case, a cage structure is obtained. In the case of a cage structure, m is preferably 2 to 4, and has a substantially cubic T8 structure, a substantially pentagonal T10 structure, and a substantially hexagonal T12 structure.

Specific examples of the siloxane compounds represented by the general formulas (a-1) and (a-3) include the following structural formulas (a-1-1), (a-1-2), and (a- What is shown by 3-1) is preferable.
Furthermore, it is also preferred that 25% or more of the hydroxyl groups in the above (a-1-1), (a-1-2) and (a-3-1) are substituted with alkoxy groups such as methoxy group and ethoxy group. It is mentioned as a thing.

  (A) The upper limit of the mass average molecular weight of the siloxane compound is 3000 or less, and preferably 2800 or less. Moreover, as a lower limit, it is preferable that it is 300 or more, and it is more preferable that it is 500 or more. By setting the lower limit to 300 or more, evaporation of this siloxane compound can be suppressed, and the film formability of the resist underlayer film composition according to the present invention can be improved.

<(A) Production method of siloxane compound>
(A) A siloxane-based compound is obtained by hydrolyzing each monomer for deriving each structural unit and subjecting it to condensation polymerization. The amount of water in the hydrolysis reaction is preferably 0.2 to 10 moles per mole of monomer. At this time, known catalysts such as metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases may be appropriately added.
As the monomer, alkoxysilanes or chlorosilanes that derive each structural unit are preferably used.

  Specific examples of the metal chelate compound include tetraalkoxytitanium, trialkoxymono (acetylacetonato) titanium, tetraalkoxyzirconium, trialkoxymono (acetylacetonato) zirconium, and the like. Examples of the organic acid include acetic acid, propionic acid, oleic acid, stearic acid, linoleic acid, salicylic acid, benzoic acid, formic acid, malonic acid, phthalic acid, fumaric acid, citric acid, and tartaric acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, sulfonic acid, methyl sulfonic acid, tosylic acid, trifluoromethane sulfonic acid, and the like.

  Organic bases include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, diazabicyclononane. , Diazabicycloundecene, tetramethylammonium hydroxide and the like. Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.

  Among these, when an epoxy group or oxetanyl group is introduced as a cross-linking group, ammonia or organic amine is used so as not to open the epoxy group or oxetanyl group during polymerization and to prevent contamination by alkali or metal impurities. It is preferable to use a basic catalyst such as Of these, tetraalkylammonium hydroxide is preferably used. In order to prevent the ring opening of the epoxy group or oxetanyl group, it is preferable to make the system in an atmosphere of pH 7 or higher. These catalysts can be used alone or in combination of two or more.

  As a reaction operation, first, each monomer is dissolved in an organic solvent, and water is added to start a hydrolysis reaction. The catalyst may be added to water or may be added to an organic solvent.

  As the organic solvent used in the reaction, those which are hardly soluble or insoluble in water are preferable. Specifically, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl-2-n-amyl ketone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol Dimethyl ether and mixtures thereof are preferred.

  Next, the catalyst is neutralized and the organic solvent layer is separated and dehydrated. This is because the remaining water causes the condensation reaction of the remaining silanol to proceed. A known dehydration method such as an adsorption method using a salt such as magnesium sulfate or a molecular sieve, or an azeotropic dehydration method while removing the solvent may be used.

  Next, an organic solvent hardly soluble or insoluble in the above water is added, and the organic solvent layer is separated and washed with water to remove the catalyst used for hydrolysis condensation. At this time, you may neutralize as needed. Subsequently, the separated organic solvent layer is dehydrated to obtain the (A) siloxane copolymer according to the present invention.

[(B) Siloxane polymer]
The resist underlayer film composition according to the present invention contains (B) a siloxane polymer.

This (B) siloxane-based polymer has a structural unit represented by the general formula (b-1).
[Wherein, R ⁷ represents a light absorbing group, R ⁸ represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and r is 0 or 1. ]

The light absorbing group is a group having absorption in a wavelength range of 150 nm to 300 nm. Examples of the light absorbing group include groups having a light absorbing portion such as a benzene ring, an anthracene ring, and a naphthalene ring. The light absorbing portion may be bonded to the Si atom of the main skeleton through an alkylene group having 1 to 20 carbon atoms which may be interrupted by one or more —O— or —O (CO) —. . One or more light absorbing portions such as a benzene ring, an anthracene ring, and a naphthalene ring may be substituted with a substituent such as an alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a hydroxy group. Among these light absorbing groups, a benzene ring is preferable. In addition to the above absorbing group, a group having a light absorbing portion having a Si—Si bond can also be used. Furthermore, these light absorption parts may be contained in the main skeleton of the siloxane polymer. Examples of the light absorbing group include aryl groups such as phenyl group, naphthyl group, methylphenyl group, ethylphenyl group, tolyl group, chlorophenyl group, bromophenyl group, and fluorophenyl group; benzyl group, phenethyl group, naphthylmethyl group, diphenyl Examples include aralkyl groups such as a methyl group, a triphenylmethyl group, and a 1-methyl-1-phenylethyl group. Of these, a phenyl group is preferred. In particular, when a phenyl group is used, light absorption can be improved, and etching resistance to oxygen-based plasma when the lower layer film is formed can be improved.
Furthermore, the (B) siloxane-based polymer preferably has at least one structural unit represented by the general formula (b-2).
[Wherein R ⁹ represents a hydrogen atom, an alkyl group, or a monovalent organic group having at least one functional group selected from carbonyl, ester, lactone, amide, ether, and nitrile, and R ¹⁰ represents hydrogen An atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group is shown, and s is 0 or 1. ]

  (B) The lower limit of the mass average molecular weight of the siloxane copolymer is preferably 8000 or more, and more preferably 10,000 or more. By making the mass average molecular weight of the component (B) 8000 or more, the film formability of the resist underlayer film formed from the resist underlayer film composition of the present invention can be improved. Moreover, 50000 or less is preferable and, as for the upper limit of the mass mean molecular weight of (B) component, 30000 or less is more preferable. (B) By making the mass mean molecular weight of a component into 50000 or less, the applicability | paintability of the composition for resist underlayer films of this invention can be improved.

<(B) Method for producing siloxane polymer>
(B) A siloxane-type copolymer is manufactured by hydrolyzing and copolymerizing each monomer containing each structural unit similarly to (A) component.

The ratio of the component (A) to the component (B) in the resist underlayer film composition according to the present invention is preferably 1: 9 to 7: 3 by mass ratio, and is 3: 7 to 6: 4. More preferably, 5: 5 is most preferable. By setting the ratio of the component (A) and the component (B) within the above range, tailing in the resist pattern formed on the resist underlayer film formed from the resist underlayer film composition can be reduced. .
Furthermore, by setting the content of the component (A) and the component (B) within the above range, a resist underlayer film capable of forming a pattern with a good shape without adding an acid generator is formed. It becomes possible to do.

[(C) Solvent]
The resist underlayer film composition according to the present invention also contains (C) a solvent (hereinafter also referred to as (C) component). Specifically, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, hexanetriol, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopro Ethers such as ether, propylene glycol monobutyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, ketones such as acetone, methyl ethyl ketone, cycloalkyl ketone, methyl isoamyl ketone, ethylene glycol dimethyl ether, Hydroxyl groups of alcohols such as ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether (PGDM), propylene glycol diethyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether All alkylate Alcohol ethers were of the like.

  These organic solvents may be used alone or in combination of two or more. The solvent is used in an amount of 1 to 100 times, more preferably 2 to 20 times the total mass of the component (A) and the component (B). By making it within this range, the applicability of the resist underlayer film composition can be improved.

[(D) Crosslinking agent]
The resist underlayer film composition according to the present invention may contain (D) a crosslinking agent (hereinafter also referred to as component (D)). (D) The film formability of the resist underlayer film can be improved by adding a crosslinking agent. As the crosslinking agent, those generally used may be used.

  Specific examples include epoxy compounds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, and cresol novolak type epoxy resin. In addition, divinylbenzene, divinylsulfone, triacryl formal, glyoxal, polyhydric alcohol acrylic ester or methacrylic ester and the like are also used.

  In addition, compounds having two or more reactive groups such as compounds in which at least two amino groups of melamine, urea, benzoguanamine, and glycoluril are substituted with a methylol group or a lower alkoxymethyl group can be used.

  Examples of the compound in which at least two amino groups of melamine are substituted with a methylol group or a lower alkoxymethyl group include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 of hexamethylol melamine are methoxymethylated, and a mixture thereof , Hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 5 methylol groups of hexamethylol melamine are acyloxymethylated, or a mixture thereof.

  Examples of the compound in which at least two of the amino groups of urea are substituted with a methylol group or a lower alkoxymethyl group include 1 to 4 methylol groups of tetramethylol urea, tetramethoxymethyl urea, tetramethoxyethyl urea, and tetramethylol urea. Examples thereof include a methoxymethyl group-formed compound or a mixture thereof.

  Compounds in which at least two of the amino groups of benzoguanamine are substituted with a methylol group or a lower alkoxymethyl group include compounds in which one to four methylol groups of tetramethylolguanamine, tetramethoxymethylguanamine, and tetramethylolguanamine are methoxymethylated And mixtures thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, compounds in which one to four methylol groups of acylmethylolguanamine are acyloxymethylated, and mixtures thereof.

  Examples of the compound in which at least two of the amino groups of glycoluril are substituted with a methylol group or a lower alkoxymethyl group include tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril, and tetramethylolglycoluril methylol groups. From 4 to methoxymethyl group, a mixture thereof, a tetramethylol glycoluril methylol group from 1 to 4 acyloxymethylated compounds, or a mixture thereof.

  These cross-linking agents may be used alone or in combination of two or more. The addition amount of the crosslinking agent is 0.1 to 50 parts by mass, and 0.5 to 40 parts by mass with respect to 100 parts by mass of the component (A) and the siloxane polymer. It is more preferable.

[(E) Acid generator]
The resist underlayer film composition according to the present invention may contain (E) an acid generator (hereinafter, also referred to as (E) component).

  Examples of the acid generator include onium salts, diazomethane derivatives, glyoxime derivatives, bissulfone derivatives, β-ketosulfone derivatives, disulfone derivatives, nitrobenzyl sulfonate derivatives, sulfonate ester derivatives, and sulfonate ester derivatives of N-hydroxyimide compounds. An acid generator can be used.

  Examples of onium salts include tetramethylammonium trifluoromethanesulfonate, tetramethylammonium nonafluorobutanesulfonate, tetra-n-butylammonium nonafluorobutanesulfonate, tetraphenylammonium nonafluorobutanesulfonate, and tetramethyl p-toluenesulfonate. Ammonium, trifluoromethanesulfonic acid diphenyliodonium, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, p-toluenesulfonic acid diphenyliodonium, p-toluenesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, trifluoromethane Triphenylsulfonium sulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) Phenylsulfonium, trifluoromethanesulfonic acid bis (p-tert-butoxyphenyl) phenylsulfonium, trifluoromethanesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, p-toluenesulfonic acid triphenylsulfonium, p-toluenesulfonic acid (p -Tert-butoxyphenyl) diphenylsulfonium, bis (p-tert-butoxyphenyl) phenylsulfonium p-toluenesulfonate, tris (p-tert-butoxyphenyl) sulfonium p-toluenesulfonate, triphenylsulfonium nonafluorobutanesulfonate , Triphenylsulfonium butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, trimethylsulfone p-toluenesulfonate , Cyclohexylmethyl trifluoromethanesulfonate (2-oxocyclohexyl) sulfonium, p-toluenesulfonate cyclohexylmethyl (2-oxocyclohexyl) sulfonium, trifluoromethanesulfonate dimethylphenylsulfonium, p-toluenesulfonate dimethylphenylsulfonium, trifluoromethane Dicyclohexylphenylsulfonium sulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, (2-norbornyl) methyl trifluoromethanesulfonate (2- Oxocyclohexyl) sulfonium, ethylenebis [Methyl (2-oxocyclopentyl) sulfonium trifluoromethanesulfonate], 1,2'-naphthylcarbonylmethyltetrahydrothiophenium triflate and the like.

  Diazomethane derivatives include bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (xylenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (cyclopentylsulfonyl) diazomethane, bis (n-butylsulfonyl) diazomethane Bis (isobutylsulfonyl) diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis (n-amylsulfonyl) diazomethane Bis (isoamylsulfonyl) diazomethane, bis (sec-amylsulfonyl) diazomethane, bis (tert-amylsulfur) Nyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-butylsulfonyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-amylsulfonyl) diazomethane, 1-tert-amylsulfonyl-1- (tert-butylsulfonyl) diazomethane Etc.

  Examples of glyoxime derivatives include bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime, bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime, bis-O- (p-toluenesulfonyl)- α-dicyclohexylglyoxime, bis-O- (p-toluenesulfonyl) -2,3-pentanedione glyoxime, bis-O- (p-toluenesulfonyl) -2-methyl-3,4-pentanedione glyoxime, Bis-O- (n-butanesulfonyl) -α-dimethylglyoxime, bis-O- (n-butanesulfonyl) -α-diphenylglyoxime, bis-O- (n-butanesulfonyl) -α-dicyclohexylglyoxime Bis-O- (n-butanesulfonyl) -2,3-pentanedione glyoxime, bis-O- ( -Butanesulfonyl) -2-methyl-3,4-pentanedione glyoxime, bis-O- (methanesulfonyl) -α-dimethylglyoxime, bis-O- (trifluoromethanesulfonyl) -α-dimethylglyoxime, bis -O- (1,1,1-trifluoroethanesulfonyl) -α-dimethylglyoxime, bis-O- (tert-butanesulfonyl) -α-dimethylglyoxime, bis-O- (perfluorooctanesulfonyl)- α-dimethylglyoxime, bis-O- (cyclohexanesulfonyl) -α-dimethylglyoxime, bis-O- (benzenesulfonyl) -α-dimethylglyoxime, bis-O- (p-fluorobenzenesulfonyl) -α- Dimethylglyoxime, bis-O- (p-tert-butylbenzenesulfonyl) α- dimethylglyoxime, bis -O- (xylene sulfonyl)-.alpha.-dimethylglyoxime, bis -O- (camphorsulfonyl)-.alpha.-dimethylglyoxime, and the like.

  Examples of bissulfone derivatives include bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane, bisethylsulfonylmethane, bispropylsulfonylmethane, bisisopropylsulfonylmethane, bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane. Can be mentioned.

  Examples of the β-ketosulfone derivative include 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane and 2-isopropylcarbonyl-2- (p-toluenesulfonyl) propane.

  Examples of disulfone derivatives include disulfone derivatives such as diphenyl disulfone derivatives and dicyclohexyl disulfone derivatives.

  Examples of the nitrobenzyl sulfonate derivative include nitrobenzyl sulfonate derivatives such as p-toluenesulfonic acid 2,6-dinitrobenzyl and p-toluenesulfonic acid 2,4-dinitrobenzyl.

  Examples of sulfonic acid ester derivatives include 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, 1,2,3-tris (p-toluenesulfonyloxy). And sulfonic acid ester derivatives such as benzene.

  Examples of sulfonic acid ester derivatives of N-hydroxyimide compounds include N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester, N-hydroxysuccinimide ethanesulfonic acid ester, N-hydroxysuccinimide 1-propanesulfonic acid. Ester, N-hydroxysuccinimide 2-propanesulfonic acid ester, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide 1-octanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxysuccinimide p-methoxybenzenesulfonic acid ester, N-hydroxysuccinimide 2-chloroethanesulfonic acid ester N-hydroxysuccinimide benzenesulfonic acid ester, N-hydroxysuccinimide 2,4,6-trimethylbenzenesulfonic acid ester, N-hydroxysuccinimide 1-naphthalenesulfonic acid ester, N-hydroxysuccinimide 2-naphthalenesulfonic acid ester, N-hydroxy 2-Phenylsuccinimide methanesulfonate, N-hydroxymaleimide methanesulfonate, N-hydroxymaleimide ethanesulfonate, N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimide methanesulfonate N-hydroxyglutarimide benzene sulfonate, N-hydroxyphthalimide methane sulfonate, N-hydroxy Phthalimidobenzenesulfonic acid ester, N-hydroxyphthalimide trifluoromethanesulfonic acid ester, N-hydroxyphthalimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, N-hydroxy -5-norbornene-2,3-dicarboximide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide trifluoromethanesulfonate, N-hydroxy-5-norbornene-2,3- Dicarboximide p-toluenesulfonic acid ester etc. are mentioned.

  These acid generators may be used alone or in combination of two or more. The addition amount of the acid generator is 0.1 to 50 parts by mass, and 0.5 to 40 parts by mass with respect to 100 parts by mass of the components (A) and (B). More preferably.

  The resist underlayer film composition according to the present invention can be obtained by mixing the necessary components (E) to (E) from the components (A). In addition, it is preferable to filter the obtained resist underlayer film composition with a filter.

[Method for forming resist underlayer film]
In order to form a resist underlayer film using the composition for a resist underlayer film according to the present invention, a spin coater, a slit nozzle coater, etc. on a film to be processed (in some cases, a bottom layer formed on the film to be processed) What is necessary is just to apply | coat using, and to heat after drying. For the heating, a one-step heating or a multi-stage heating method can be used. When using the multi-stage heating method, for example, it is preferable to first heat at 100 ° C. to 120 ° C. for 60 seconds to 120 seconds, then at 200 ° C. to 250 ° C. for 60 seconds to 120 seconds

  The resist underlayer film thus formed preferably has a thickness of 15 nm to 200 nm. Thereafter, a resist film composition is provided on the resist underlayer film in a thickness of, for example, 100 nm to 300 nm to manufacture a resist film.

[Pattern formation method]
The resist underlayer film formed from the resist underlayer film composition according to the present invention is preferably used as an intermediate layer in a multilayer resist process such as a three-layer resist process.
Examples of the pattern forming method using the resist underlayer film according to the present invention include the following methods.

  As shown in FIG. 1A, the lower layer film composition is applied onto the substrate 20 using a spin coat method or the like, and baked at a predetermined temperature to form the lower layer film 26 (bottom layer). Next, a resist underlayer film composition is applied onto the underlayer film 26 using a spin coating method or the like, and baked at a predetermined temperature to form the resist underlayer film 24. Next, the resist film composition is applied using a spin coating method or the like in the same manner as described above. Next, pre-baking is performed at a predetermined temperature to form a resist film 22 (see FIG. 1A). The prebaking conditions are 150 ° C. to 300 ° C., and preferably 30 seconds to 300 seconds.

  Next, the resist underlayer film 22 is etched using the resist film 24 on which the pattern is formed as a mask, and the resist pattern is transferred to the resist underlayer film 22 (see FIG. 1B). The lower layer film 26 is etched using the resist film 24 and the resist lower layer film 22 as a mask, and the resist pattern is transferred to the lower layer film 26 (see FIG. 1C). At this time, the resist film 24 may also be removed by etching at the same time. Next, etching is performed in the same manner as described above to form a pattern on the substrate 20 (see FIG. 1D).

  Since this lower layer film 26 acts as a mask when etching the substrate 20, it is desirable that the lower layer film 26 has high etching resistance and is not required to be mixed with the upper resist lower layer film 22. Alternatively, it is desirable to crosslink with an acid. Specifically, it is preferable to use a resin such as cresol novolak, naphthol novolak, catol dicyclopentadiene novolak, amorphous carbon, polyhydroxystyrene, (meth) acrylate, polyimide, polysulfone.

  Moreover, as a resist composition used for formation of the resist film 24, a well-known thing can be used like a mixture of base resin, an organic solvent, and an acid generator, for example.

  Base resins include polyhydroxystyrene and derivatives thereof, polyacrylic acid and derivatives thereof, polymethacrylic acid and derivatives thereof, copolymers selected from hydroxystyrene, acrylic acid, methacrylic acid and derivatives thereof, cycloolefin and derivatives thereof. Examples thereof include at least one polymer selected from the group consisting of a derivative, maleimide, acrylic acid, and three or more copolymers selected from acrylic acid and derivatives thereof, polynorbornene, and a metathesis ring-opening polymer. In addition, the main skeleton remains after the induction, such as acrylic acid derivatives such as acrylic acid esters, methacrylic acid derivatives such as methacrylic acid derivatives, and alkoxystyrenes such as hydroxystyrene derivatives. Means what

  As a resist for KrF excimer laser, a copolymer of any one of polyhydroxystyrene, hydroxystyrene and styrene and any one of acrylic acid ester, methacrylic acid ester and maleimide N carboxylic acid ester is used. Can be mentioned. Further, as resists for ArF excimer laser, acrylic acid ester-based, methacrylic acid ester-based, alternating copolymerization of norbornene and maleic anhydride, alternating copolymerization of tetracyclododecene and maleic anhydride, polynorbornene-based And metathesis polymerization systems based on ring-opening polymerization, but are not limited to these polymerization polymers.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
[Synthesis Example 1]
A siloxane compound (a-2-1) as component (A) was synthesized as follows.
30 L of phenyltriethoxysilane (1.25 mol) was charged into a 1 L jacketed flask equipped with a thermometer, a stirrer, a reflux condenser, and a discharge cock, and the system temperature was adjusted to 25 ° C. Subsequently, hydrochloric acid water consisting of 0.23 g (0.006 mol) of hydrochloric acid and 67.5 g (3.75 mol) of water was dropped, and the mixture was kept at 25 ° C. for 8 hours. In the middle, the reaction mass changed from a dispersed state to a uniform layer, and a rapid exotherm was observed up to 48 ° C. Thereafter, 300 g of toluene was added and dissolved, followed by separation and washing with water until the reaction mass became neutral, and the obtained toluene layer was allowed to stand at 5 ° C. or less for 48 hours. Thereafter, the precipitated white crystals were separated by filtration, suspended and purified with toluene, and dried to obtain 13.2 g of white crystals.

  When the molecular weight of the obtained white crystals was determined by gel perem chromatography (GPC), the weight average molecular weight was 550 in terms of polystyrene, GPC spectrum (see FIG. 2), IR spectrum (see FIG. 3), and By analysis of 1H-NMR spectrum (see FIG. 4), the white crystals are cyclic tetramer 1,3,5,7-tetraphenylcyclotetrasiloxane-1,3,5,7-tetraol. It was confirmed that there was.

[Synthesis Example 2]
A siloxane compound (a-3-1) as component (A) was synthesized as follows.
30 L of phenyltriethoxysilane (1.25 mol) was charged into a 1 L jacketed flask equipped with a thermometer, a stirrer, a reflux condenser, and a discharge cock, and the system temperature was adjusted to 25 ° C. Subsequently, hydrochloric acid water consisting of 0.23 g (0.006 mol) of hydrochloric acid and 67.5 g (3.74 mol) of water was dropped, and the mixture was kept at 25 ° C. for 8 hours. In the middle, the reaction mass changed from a dispersed state to a uniform layer, and a rapid exotherm was observed up to 48 ° C. Thereafter, 300 g of toluene was added and dissolved, and the mixture was washed with water until the reaction mass became neutral. Toluene was recovered from the obtained toluene layer under reduced pressure to obtain 152.5 g of a white powdery silicone composition. .
When the molecular weight of the obtained siloxane compound was determined by gel permeation chromatography, the weight average molecular weight was 920 in terms of polystyrene. Cyclic phenylsiloxanes were also included.
The siloxane polymer as component (B) was synthesized as follows.

[Synthesis Example 3]
The siloxane polymer (b-1-1) as component (B) was synthesized as follows.
In a 1-liter four-necked flask, 379.8 g (2.13 mol) of methyltriethoxysilane, 6.5 g (0.027 mol) of phenyltriethoxysilane, 98.6 g (0.6 mol) of triethoxysilane 0.0004 mol and water 108 g (6 mol) were charged and reacted with stirring. Thereafter, water and alcohol were removed using an evaporator to obtain a siloxane polymer (b-1-1).
When the molecular weight of the siloxane-based polymer was determined by GPC, the mass average molecular weight was 9700.

[Examples 1 to 5]
<Preparation of composition for resist underlayer film>
Components (A) and (B) having a mass ratio shown in Table 1 were mixed with a mixed solvent of propylene glycol monomethyl ether acetate: ethyl lactate = 6: 4 to obtain a resist underlayer film composition. The solid content concentration of the component (A) and the component (B) was adjusted to 2.5% by mass.
(A) A siloxane compound represented by the following structural formula (a-2-1) synthesized in Synthesis Example 1 as a component and a siloxane compound represented by (a-3-1) synthesized in Synthesis Example 2 (Mixture with cyclic siloxane compound) was used. Further, as the component (B), a siloxane polymer (mass average molecular weight: 9700) represented by the following structural formula (b-1-1) synthesized in Synthesis Example 3 was used.

[Comparative Example 1]
As shown in Table 1, a resist underlayer film composition was obtained in the same manner as in the above Example using only the component (B) without using the component (A).
[Comparative Example 2]
As shown in Table 1, without using the component (A), using only the component (B), and using MX-270 manufactured by Sanwa Chemical Co., Ltd. as a crosslinking agent in an amount of 3% by mass based on the component (A) In the same manner as above, a resist underlayer film composition was obtained.

<Formation of resist pattern>
A bottom layer (underlayer film) having a thickness of 220 nm is formed on a silicon wafer by applying a composition for forming an underlayer film containing a novolak resin using a conventional resist coater and performing a heat treatment at 250 ° C. for 90 seconds. ) Was formed.
Next, by applying the resist underlayer film compositions of Examples 1 to 5 and Comparative Examples 1 and 2 on the bottom layer and performing heat treatment at 250 ° C. for 90 seconds, a thickness of 600 mm is obtained. A resist underlayer film was formed. Further, a resist composition was coated on the resist underlayer film (antireflection film) to form a resist layer, and exposed and developed with an ArF excimer laser to form a line pattern.
The resist compositions used in Examples 1 to 5 and Comparative Example 1 were prepared by mixing the following components.
Resin: Resin having a unit represented by the following formula (C1: C2: C3 = 3: 5: 2, molecular weight 10,000) 100% by mass
Acid generator: 1) 1.6% by mass of a compound of the following formula
2) 3.5% by mass of the compound of the following formula
Acid quencher: Triethanolamine 0.3% by mass
Solvent: Propylene glycol monomethyl ether acetate: Ethyl lactate = 8: 2

<Evaluation of resist pattern>
The shape of the resist pattern formed above was evaluated. This evaluation was performed by observing the pattern and the bottoming state of the resist pattern with a SEM (transmission electron microscope). As a result, in Examples 1 to 5, the tailing in the resist pattern was reduced as compared with Comparative Examples 1 and 2, and a good pattern shape was shown. In particular, it was shown that Examples 4, 5, and 6 can form a pattern having a particularly good shape.

It is the figure which showed the process of forming a resist pattern using the composition for resist underlayer films concerning this invention. 3 is a GPC spectrum of cyclic phenylsiloxane of Synthesis Example 1. 2 is an IR spectrum of the cyclic phenylsiloxane of Synthesis Example 1. 2 is a 1H-NMR spectrum of a cyclic phenylsiloxane of Synthesis Example 1.

Explanation of symbols

10, 20 Substrate 12, 22 Resist underlayer film 14, 24 Resist film 26 Underlayer film

Claims (7)

  A composition for a resist underlayer film comprising (A) a siloxane compound having a mass average molecular weight of 3000 or less and (B) a siloxane polymer.   The composition for a resist underlayer film according to claim 1, wherein the (B) siloxane polymer has a mass average molecular weight of 8000 or more.   The composition for a resist underlayer film according to claim 1 or 2, wherein a mass ratio of the (A) siloxane compound to the (B) siloxane polymer is 1: 9 to 7: 3.   The composition for a resist underlayer film according to claim 1, wherein the (A) siloxane compound has a cyclic structure or a cage structure. The said (A) siloxane type compound contains at least 1 sort (s) of the compound which has a structure shown by the following general formula (a-1), (a-2), (a-3). The composition for resist underlayer films described in 1.
[Wherein R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ are each independently a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group, and R ² is independently a substituted or unsubstituted carbonization. A hydrogen group, and in (a-1), R ¹ and R ³ and / or R ⁴ and R ⁵ may be —O—, m is 1 to 8, and n Is from 2 to 8. ] The composition for a resist underlayer film according to claim 1, wherein the (B) siloxane-based polymer has a structural unit represented by the following general formula (b-1).
[Wherein, R ⁷ represents a monovalent organic group having a light absorbing group, R ⁸ represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group, and r is 0 or 1; is there. ] A resist underlayer film obtained by applying the composition for resist underlayer film according to claim 1 and baking at a predetermined temperature.