TW201439685A - Composition for forming anti-etching under-layer film and pattern formation method - Google Patents

Abstract

The purpose of the present invention is to provide a composition for forming an anti-etching under-layer film, which has excellent storage stability and high coating defect improvement property capable of suppressing the generation of coating defects, and a pattern formation method using the composition. The composition for forming an anti-etching under-layer film in accordance with the present invention is an anti-etching under-layer film formation composition, which comprises [A] a polysiloxane and [B] a solvent. The [B] solvent includes (B1) an organic solvent, which is a compound expressed by formula (1) or a carbonate compound and has a standard boiling point of 150.0 DEG C or higher. The standard boiling point of the (B1) organic solvent is preferably 180 DEG C or higher. In addition, the content percentage of the (B1) organic solvent in the [B] solvent is preferably more than 1 mass% and less than 50 mass%. The static surface tension of the (B1) organic solvent is preferably more than 20 mN/m and less than 50 mN/m.

Description

Anti-corrosion underlayer film forming composition and pattern forming method

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

In the manufacture of a semiconductor device, a multilayer resist process has been used in accordance with the miniaturization of the pattern associated with high integration. This process is to apply a composition for forming a resist underlayer film on a substrate to be processed, to form a resist underlayer film, and apply a resist composition on the resist underlayer film to form a resist film. Next, the resist film is exposed through a mask by a reduction projection exposure apparatus (stepper) or the like, and developed as an appropriate developing liquid to form a resist pattern. Then, the resist pattern is used as a mask to dry-etch the underlayer film, and the obtained underlayer film pattern is used as a mask to further dry-etch the substrate to be processed, thereby forming a desired pattern on the substrate to be processed.

As the composition for forming a resist underlayer film, it has been disclosed that a composition containing a polyoxyalkylene can be used as a resist having a high etching selectivity for a resist film, and a resist underlayer film can be surely etched (refer to the special opening). Japanese Patent Publication No. 2004-310019 and JP-A-2005-018054.

However, the preservation stability of the above composition is insufficient, if When the storage period is lengthened, even if the film thickness of the resist underlayer film formed under the same manufacturing conditions is different, a difference occurs. Moreover, in the formation of the resist underlayer film in the past composition, the polymer component dissolved in the composition is solidified, and the coating defect is abnormal in the formed resist underlayer film due to the formed solid matter. .

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2004-310019

[Patent Document 2] JP-A-2005-018054

The present invention has been made in view of the above circumstances, and an object of the invention is to provide a composition for forming a resist underlayer film having excellent storage stability and a coating defect-improving property capable of suppressing occurrence of coating defects, and a composition for using the composition. Pattern formation method.

The invention for solving the above problems is a composition for forming a resist underlayer film, which comprises a composition for forming a resist underlayer film of [A] polysiloxane and [B] solvent, and [B] a solvent is included ( B1) a compound represented by the following formula (1) or a carbonate compound, and an organic solvent having a normal boiling point of 150.0 ° C or higher (hereinafter also referred to as "(B1) organic solvent"),

(In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a fluorenyl group having 1 to 4 carbon atoms; R ³ is a hydrogen atom or a methyl group, and n is 1 to 4 An integer, when n is 2 or more, a plurality of R ^{3 's} may be the same or different).

The composition for forming a resist underlayer film of the present invention has a storage stability which can reduce a change in the film thickness of the undercoat film due to storage of the composition, and suppresses the specific organic solvent containing the high-boiling component. The unnecessary evaporation of the solvent during the formation of the under-etch resist film suppresses the improvement of the coating defect which is high in the solidification of the polymer component dissolved in the composition.

(B1) The standard boiling point of the organic solvent is preferably 180 ° C or higher. By setting the standard boiling point of the (B1) organic solvent to the above specific range, the storage stability and the coating defect improving property of the composition can be improved.

The content of the (B1) organic solvent in the solvent [B] is preferably from 1% by mass to 50% by mass. By setting the content ratio of the (B1) organic solvent in the solvent [B] to the above specific range, the storage stability and the coating defect improving property of the composition can be effectively improved.

(B1) The static surface tension of the organic solvent is preferably 20 mN/m or more and 50 mN/m or less. By making the static surface tension of the (B1) organic solvent into the above specific range, the [A] polyoxane of the composition can be improved. Solubility, as a result, improves coating defect improvement.

The solvent [B] preferably further comprises (B2) an alkylene glycol monoalkyl ether acetate compound having a standard boiling point of less than 150.0 ° C (hereinafter also referred to as "B2 compound"). By [B [solvent further contains the above-mentioned specific (B2) compound, the solubility of the [A] polyoxane to the [B] solvent of the composition can be improved, and as a result, storage stability and coating can be further improved. Defect improvement.

The (B2) alkanediol monoalkyl ether acetate compound is preferably a propylene glycol monoalkyl ether acetate compound. By making the (B2) compound into the specific compound described above, the solubility of the [A] polyoxane to the [B] solvent of the composition can be further improved, and as a result, the storage stability and the coating defect improvement can be further improved. .

Since the composition for forming a resist underlayer film has the above properties, it can be preferably used in a multilayer resist process, and a resist underlayer film having less coating defects can be formed.

The composition for forming a resist underlayer film preferably further contains a [C] acid diffusion controlling agent. By further including the [C] acid diffusion controlling agent in the composition for forming a resist underlayer film, the above effect can be maintained, and on the one hand, acid diffusion of the resist film caused by the underlayer film can be effectively suppressed, and as a result, The shape of the resist pattern formed by the multilayer resist process can be improved.

The [C] acid diffusion controlling agent is preferably a nitrogen-containing compound. By using the [C] acid diffusion controlling agent as the nitrogen-containing compound, the composition can be more effectively inhibited from diffusing, and as a result, the shape of the resist pattern formed by the multilayer resist process can be further improved.

The [A] polyoxyalkylene is preferably a hydrolysis condensate of a compound containing a decane compound represented by the following formula (i), [Chem. 2] R ^A _a SiX _4-a (i)

(In the formula (i), R ^A is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms or a cyano group, and the above alkyl group Part or all of a hydrogen atom may be substituted with an epoxyalkyloxy group, an acid anhydride group or a cyano group, and some or all of the hydrogen atoms of the above aryl group may be substituted with a hydroxyl group, and X is a halogen atom or -OR ^B , but R ^B For a monovalent organic group, a is an integer from 0 to 3, but when R ^A and X are plural, respectively, the plural R ^A and X may be the same or different.

By making [A] polyoxyalkylene a hydrolysis condensate of the above specific compound, the storage stability and coating defect improvement property of the composition can be further improved.

The pattern forming method of the present invention has the following steps: (1) a step of forming a resist underlayer film on a substrate to be processed using the composition for forming a resist underlayer film, and (2) using a resist composition for the above-mentioned anti-corrosion a step of forming a resist film on the underlying film, (3) a step of exposing the resist film by irradiation of exposed light through the photomask, and (4) developing the exposed resist film to form an anti-etching film a step of etching the pattern, and (5) using the above resist pattern as a mask, sequentially etching the resist The steps of the underlayer film and the substrate to be processed.

Since the composition for forming a resist underlayer film has the above properties, it is possible to form a good resist pattern according to the pattern forming method of the present invention.

Here, the "standard boiling point" (hereinafter also referred to simply as "boiling point") means the boiling point at atmospheric pressure. Further, the term "static surface tension" means the surface tension when the liquid surface is at rest. The static surface tension of the present specification is a value measured by the Wilhelmy method at 25 °C. Further, the "monovalent organic group" means a valent group containing at least one carbon atom.

As described above, the composition for forming a resist underlayer film of the present invention has excellent storage stability and high coating defect improving property. According to this, the composition for forming a resist underlayer film and the pattern forming method can be preferably used in a manufacturing process of a semiconductor device in which the pattern is refined.

<Composition for forming a resist underlayer film>

The composition for forming a resist underlayer film of the present invention contains [A] a polysiloxane and a solvent [B]. Further, the composition for forming a resist underlayer film may further contain a [C] acid diffusion controlling agent as a preferable component. Further, the composition for forming a resist underlayer film may contain any other constituents as long as the effects of the present invention are not impaired. Minute.

Further, since the composition for forming a resist underlayer film has high coating defect improving property, it can be preferably used in a multilayer resist process as shown in the pattern forming method described later, and can be formed into a coating. A low-resistance anti-fouling film. Hereinafter, each component will be described in detail.

<[A] polyoxane>

[A] Polysiloxane is not particularly limited as long as it has a polymer having a decane bond, but is preferably a compound hydrolysis condensate containing a decane compound represented by the above formula (i). Here, the "hydrolysis condensate of a compound containing a decane compound" means a hydrolysis condensate of a decane compound represented by the above formula (i), or a decane compound represented by the above formula (i) and the formula (i) A hydrolysis condensate of a decane compound other than a decane compound (hereinafter also referred to as "another decane compound"). The other decane compound is not particularly limited as long as it can form a hydrolyzed stanol group.

In the above formula (i), R ^A is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms or a cyano group. Some or all of one of the hydrogen atoms of the above alkyl group may be substituted with an epoxyalkyloxy group, an acid anhydride group or a cyano group. Some or all of one of the hydrogen atoms of the above aryl group may be substituted with a hydroxyl group. X is a halogen atom or -OR ^B . However, R ^B is a monovalent organic group. a is an integer from 0 to 3. However, when R ^A and X are each plural, the plural R ^A and X may be the same or different.

The alkyl group having 1 to 5 carbon atoms represented by the above R ^A is exemplified by a linear alkyl group such as a methyl group, an ethyl group, a n-propyl group, a n-butyl group or a n-pentyl group; an isopropyl group, an isobutyl group, A branched alkyl group such as a second butyl group, a tert-butyl group or an isopentyl group. Among these, a methyl group and an ethyl group are more preferable, and a methyl group is more preferable.

The alkenyl group having 2 to 10 carbon atoms represented by the above R ^A is exemplified by, for example, a vinyl group, a 1-propen-1-yl group, a 1-propen-2-yl group, a 1-propen-3-yl group, and a 1-butene-1. -yl, 1-buten-2-yl, 1-buten-3-yl, 1-buten-4-yl, 2-buten-1-yl, 2-buten-2-yl, 1- Pentene-5-yl, 2-penten-1-yl, 2-penten-2-yl, 1-hexen-6-yl, 2-hexen-1-yl, 2-hexene-2- Base.

The aryl group having 6 to 20 carbon atoms represented by the above R ^A is exemplified by, for example, a phenyl group, a naphthyl group, a methylphenyl group, an ethylphenyl group [*2] [*3] and the like. Further, the above aryl group may be substituted with a halogen atom. The aryl group substituted with a halogen atom is exemplified by, for example, a chlorophenyl group, a bromophenyl group, a fluorophenyl group or the like.

In the present specification, the above "epoxy group" includes both an epoxy group and an oxetanyl group.

The above alkyl group substituted with an epoxyalkyloxy group is exemplified by an epoxyethyl alkyloxy group such as 2-glycidoxyethyl group, 3-glycidoxypropyl group or 4-glycidoxybutyl group. 3-ethyl-3-oxetanylpropyl, 3-methyl-3-oxetanylpropyl, 3-ethyl-2-oxetanylpropyl, 2-oxo An oxetanylalkyloxy group such as a heterocyclic butylethyl group. Among these, 3-glycidoxypropyl group and 3-ethyl-3-oxetanylpropyl group are preferred.

The alkyl group substituted with an acid anhydride group is exemplified by an ethyl group substituted with a 2-succinic anhydride group, a propyl group substituted with a 3-succinic anhydride group, a butyl group substituted with a 4-succinic anhydride group, and the like. Among these, a propyl group substituted with a 3-succinic anhydride group is more preferred.

The above alkyl group substituted with a cyano group is exemplified by, for example, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl or the like.

The above aryl group substituted with a hydroxy group is exemplified by, for example, a 4-hydroxyphenyl group, a 4-hydroxy-2-methylphenyl group, a 4-hydroxynaphthyl group or the like. Among these, a 4-hydroxyphenyl group is preferred.

The halogen atom represented by X above is, for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like.

The one-valent organic group in the above R ^B is preferably an alkyl group or an alkylcarbonyl group. The above alkyl group is preferably a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group or a t-butyl group, more preferably a methyl group or an ethyl group, and most preferably methyl. Further, the above alkylcarbonyl group is preferably a methylcarbonyl group or an ethylcarbonyl group.

The decane compound represented by the above formula (i) is exemplified by, for example, a trialkoxy decane containing an aromatic ring, which is a phenyltrimethoxydecane, a 4-methylphenyltrimethoxydecane, or a 4-ethylphenyl group. Trimethoxydecane, 4-hydroxyphenyltrimethoxydecane, 3-methylphenyltrimethoxydecane, 3-ethylphenyltrimethoxydecane, 3-hydroxyphenyltrimethoxydecane, 2-methyl Phenyltrimethoxydecane, 2-ethylphenyltrimethoxydecane, 2-hydroxyphenyltrimethoxydecane, 2,4,6-trimethylphenyltrimethoxydecane, etc.; Alkoxydecanes, methyltrimethoxydecane, methyltriethoxydecane, methyltri-n-propoxydecane, methyltriisopropoxydecane, methyltri-n-butoxydecane, A Tris-t-butoxydecane, methyltri-t-butoxydecane, methyltriphenoxydecane, methyltriethyl 醯 methoxy decane, methyl trichloro decane, methyl triisopropoxy decane, methyl dimethyl (dimethyl methoxy) decane, methyl methoxy (methoxy ethoxy) decane, methyl ginseng ( Methyl ethyl ketone oxime) decane, methyl ginseng (trimethyl decyloxy) decane, methyl decane, ethyl trimethoxy decane, ethyl triethoxy decane, ethyl tri-n-propoxy decane, Ethyltriisopropoxydecane, ethyltri-n-butoxydecane, ethyltri-t-butoxydecane, ethyltri-t-butoxydecane, ethyltriphenoxydecane, ethyl Shuangshen (trimethyldecyloxy)decane, ethyldichlorodecane, ethyltriethoxydecane, ethyltrichlorodecane, n-propyltrimethoxydecane, n-propyltriethoxydecane, N-propyl tri-n-propoxy decane, n-propyl triisopropoxy decane, n-propyl tri-n-butoxy decane, n-propyl tri-second butoxy decane, n-propyl tri-tertiary Oxydecane, n-propyltriphenoxydecane, n-propyltriethoxydecane, n-propyltrichlorodecane, isopropyltrimethoxydecane, isopropyltriethoxydecane, isopropyl Tri-n-propoxy oxime , isopropyl triisopropoxy decane, isopropyl tri-n-butoxy decane, isopropyl tri-second butoxy decane, isopropyl tri-t-butoxy decane, isopropyl triphenyl Oxydecane, n-butyltrimethoxydecane, n-butyltriethoxydecane, n-butyltri-n-propoxydecane, n-butyltriisopropoxydecane, n-butyltri-n-butoxydecane , n-butyltri-t-butoxydecane, n-butyltri-t-butoxydecane, n-butyltriphenoxydecane, n-butyltrichlorodecane, 2-methylpropyltrimethoxy Decane, 2-methylpropyltriethoxydecane, 2-methylpropyltri-n-propoxydecane, 2-methylpropyltriisopropoxydecane, 2-methylpropyltri-n-butoxy Baseline, 2-methylpropyltri-t-butoxydecane, 2-methylpropyltri-t-butoxydecane, 2-methylpropyltriphenoxydecane, 1-methylpropane base Trimethoxydecane, 1-methylpropyltriethoxydecane, 1-methylpropyltri-n-propoxydecane, 1-methylpropyltriisopropoxydecane, 1-methylpropyltri n-Butoxydecane, 1-methylpropyltri-t-butoxydecane, 1-methylpropyltri-t-butoxydecane, 1-methylpropyltriphenoxydecane, third Butyl trimethoxy decane, tert-butyl triethoxy decane, tert-butyl tri-n-propoxy decane, tert-butyl triisopropoxy decane, tert-butyl tri-n-butoxy decane, Tert-butyltri-t-butoxydecane, tert-butyltri-t-butoxydecane, tert-butyltriphenoxydecane, tert-butyltrichlorodecane, tert-butyldichloro a decane or the like; as an alkenyl trialkoxy decane, a vinyl trimethoxy decane, a vinyl triethoxy decane, a vinyl tri-n-propoxy decane, a vinyl triisopropoxy decane, a vinyl three n-Butoxydecane, vinyl tri-t-butoxydecane, vinyl tri-t-butoxydecane, vinyltriphenyloxydecane, allyltrimethoxydecane, allyl triethoxy Base decane Tri-n-propoxy decane, allyl triisopropoxy decane, allyl tri-n-butoxy decane, allyl tri-second butoxy decane, allyl tri-tert-butoxy Decane, allyltriphenoxydecane, etc.; as tetraalkoxynonane, tetramethoxynonane, tetraethoxydecane, tetra-n-propoxydecane, tetraisopropoxydecane, tetra-n-butyl a oxydecane, a tetra-butoxy decane, a tetra-butoxy decane, a tetraaryl decane, a tetraphenoxy decane, etc.; and an epoxy group-containing decane, a 3- Oxecyclobutyloxypropyltrimethoxydecane, 3-oxetanyloxypropyltrimethoxydecane, 3-glycidoxypropyltrimethoxydecane, etc.; As the acid anhydride-containing decane, 3-(trimethoxydecyl)propyl succinic anhydride, 2-(trimethoxydecyl)ethyl succinic anhydride, 3-(trimethoxydecyl)propyl succinic anhydride And 2-(trimethoxydecyl)ethyl succinic anhydride or the like; tetrachlorodecane or the like, tetrachlorodecane or the like.

The above other decane compounds are exemplified by, for example, benzyltrimethoxydecane, phenethyltrimethoxydecane, 4-phenoxyphenyltrimethoxydecane, 4-aminophenyltrimethoxydecane, 4-dimethylamine. Phenyltrimethoxydecane, 4-ethenylaminophenyltrimethoxydecane, 3-methoxyphenyltrimethoxydecane, 3-phenoxyphenyltrimethoxydecane, 3-amino Phenyltrimethoxydecane, 3-dimethylaminophenyltrimethoxydecane, 3-ethenylaminophenyltrimethoxydecane, 2-methoxyphenyltrimethoxydecane, 2-phenoxy Phenyltrimethoxydecane, 2-aminophenyltrimethoxydecane, 2-dimethylaminophenyltrimethoxydecane, 2-ethenylaminophenyltrimethoxydecane, 4-methyl Benzyltrimethoxydecane, 4-ethylbenzyltrimethoxydecane, 4-methoxybenzyltrimethoxydecane, 4-phenoxybenzyltrimethoxydecane, 4-hydroxybenzyltrimethoxy Decane, 4-aminobenzyltrimethoxydecane, 4-dimethylaminobenzyltrimethoxydecane, 4-ethenylaminobenzyltrimethoxydecane, and the like.

The conditions for carrying out the above hydrolysis and condensation are not particularly limited as long as at least a part of the decane compound represented by the above formula (i) is hydrolyzed, and the hydrolyzable group (-OR ^B ) is converted into a stanol group, and the condensation reaction is not particularly limited. It can be implemented in the following ways.

The water used in the above hydrolysis condensation is preferably used for reverse osmosis Water purified by membrane treatment, ion exchange treatment, distillation, and the like. By using the purified water, side reactions can be suppressed and hydrolysis reactivity can be improved. The amount of water used is 1 mol, more preferably 0.1 to 3 mol, more preferably 0.3 to 2 mol, more preferably 0.5, based on the total amount of the hydrolyzable group of the decane compound represented by the above formula (i). ~1.5 moles. By using this amount of water, the reaction rate of hydrolysis and condensation can be optimized.

The solvent to be used in the above hydrolysis condensation is not particularly limited, but is preferably ethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate. Ester, propionate. Among these, it is more preferably diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate or 3-methyl Methyl oxypropionate, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol).

The above hydrolysis condensation reaction is preferably carried out in an acid catalyst (for example, hydrochloric acid, sulfuric acid, nitric acid, formic acid, oxalic acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, phosphoric acid, acidic ion exchange resin, various Lewis acids), alkali catalyst (for example, ammonia, primary amines, secondary amines, tertiary amines, nitrogen-containing compounds such as pyridine; basic ion exchange resins; hydroxides such as sodium hydroxide; carbonates such as potassium carbonate; carboxylic acids such as sodium acetate It is carried out in the presence of a catalyst such as a salt; various Lewis bases; or an alkoxide (for example, zirconium alkoxide, titanium alkoxide or aluminum alkoxide). For example, aluminum aluminoxide can be used for the aluminum alkoxide. The amount of the catalyst used is preferably 0.2 mol or less, more preferably 0.00001 to 0.1 mol, based on the monomer 1 mol of the hydrolyzable decane compound, from the viewpoint of promoting the hydrolysis condensation reaction.

The reaction temperature and reaction time in the above hydrolysis condensation are appropriately set. For example, the following conditions can be employed. The reaction temperature is preferably from 40 ° C to 200 ° C, more preferably from 50 ° C to 150 ° C. The reaction time is preferably from 30 minutes to 24 hours, more preferably from 1 hour to 12 hours. By setting the reaction temperature and the reaction time, the hydrolysis condensation reaction can be carried out most efficiently. In the hydrolysis condensation reaction, a hydrolyzable decane compound, water, and a catalyst may be added to the reaction system at a time, and the reaction may be carried out in one stage, or a hydrolyzable decane compound, water, and a catalyst may be added to the reaction system in portions. The hydrolysis condensation reaction is carried out in multiple stages. Further, after the hydrolysis condensation reaction, a dehydrating agent may be added, followed by evaporation, and water and the produced alcohol are removed from the reaction system.

The content of the [A] polyoxane in the composition for forming a resist underlayer film is preferably 80% by mass or more, more preferably 90% by mass or more based on the total solid content in the composition for forming a resist underlayer film. It is better to be 95% by mass or more. Further, the composition for forming a resist underlayer film may contain only one kind of [A] polyoxyalkylene, and may contain two or more kinds.

The polystyrene-equivalent weight average molecular weight (Mw) of [A] polyoxyalkylene measured by a gel permeation chromatography (GPC) is usually 500 to 50,000, preferably 1,000 to 30,000, more preferably 1,000 to 15,000. And better for 1,000~5,000.

<[B] Solvent>

[B] The solvent is a solvent containing (B1) an organic solvent. Further, the [B] solvent may also contain a (B2) compound. Further, the [B] solvent may include the above (B1) organic solvent or (B2) compound, without damaging the effects of the present invention. Other solvents. Each of the above components may be used singly or in combination of two or more. Hereinafter, each component will be described in detail.

[(B1) organic solvent]

(B1) The organic solvent is a compound represented by the above formula (1) or a carbonate compound, and an organic solvent having a normal boiling point of 150.0 ° C or higher. By setting the above-mentioned specific organic solvent containing a high boiling point component in the composition for forming a resist underlayer film, it is possible to reduce the excellent storage stability of the thickness of the underlayer film formed by the storage of the composition, and to suppress the resistance. The solvent does not need to be evaporated during the formation of the underlayer film, and the coating defect improving property of the solidification of the polymer component dissolved in the composition is suppressed.

The standard boiling point of the organic solvent (B1) is preferably 160 ° C or higher, more preferably 170 ° C or higher, and still more preferably 180 ° C or higher. By setting the standard boiling point of the (B1) organic solvent to the above range, the storage stability and the coating defect improving property of the composition can be improved.

The standard boiling point of the organic solvent (B1) is preferably 300 ° C or lower, more preferably 280 ° C or lower, still more preferably 250 ° C or lower, and most preferably 220 ° C or lower. By setting the standard boiling point of the above (B1) organic solvent to the above range, the residue of the organic solvent after the formation of the undercoat film can be reduced.

In the above formula (1), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a mercapto group having 1 to 4 carbon atoms. R ³ is a hydrogen atom or a methyl group. n is an integer from 1 to 4. When n is 2 or more, a plurality of R ^{3 's} may be the same or different.

The alkyl group having 1 to 4 carbon atoms represented by the above R ¹ and R ² is exemplified by a linear alkyl group such as a methyl group, an ethyl group, a n-propyl group or a n-butyl group; an isopropyl group, an isobutyl group, and a second group; a branched alkyl group such as a butyl group or a tributyl group.

The fluorenyl group having 1 to 4 carbon atoms represented by the above R ¹ and R ² is exemplified by a methyl group, an ethyl group, a propyl group or the like.

The (B1) organic solvent which is formed from the compound represented by the above formula (1) is exemplified by, for example, a glycol compound: ethylene glycol (boiling point: 197 ° C) and 1,2-propanediol (boiling point: 188 ° C). Triethylene glycol (boiling point: 165 ° C); etc.; as a polyol partial ether compound, ethylene glycol monopropyl ether (boiling point: 150 ° C), ethylene glycol monobutyl ether (boiling point: 171 ° C), ethylene two Alcohol monophenyl ether (boiling point: 244 ° C), diethylene glycol monomethyl ether (boiling point: 194 ° C), diethylene glycol monoethyl ether (boiling point: 202 ° C), triethylene glycol monomethyl ether (Boiling point: 249 ° C), diethylene glycol monoisopropyl ether (boiling point: 207 ° C), diethylene glycol monobutyl ether (boiling point: 231 ° C), triethylene glycol monobutyl ether (boiling point: 271 °C), ethylene glycol monoisobutyl ether (boiling point: 161 ° C), diethylene glycol monoisobutyl ether (boiling point: 220 ° C), dipropylene glycol monomethyl ether (boiling point: 187 ° C), tripropylene glycol single Methyl ether (boiling point: 242 ° C), dipropylene glycol monopropyl ether (boiling point: 212 ° C), propylene glycol monobutyl ether (boiling point: 170 ° C), dipropylene glycol monobutyl ether (boiling point: 231 ° C), etc.; Ether compound, diethylene glycol dimethyl ether (boiling : 162 ° C), triethylene glycol dimethyl ether (boiling point: 216 ° C), diethylene glycol methyl ethyl ether (boiling point: 176 ° C), diethylene glycol diethyl ether (boiling point: 189 ° C) , diethylene glycol dibutyl ether (boiling point: 255 ° C), dipropylene glycol dimethyl ether (boiling point: 171 ° C), diethylene glycol monoethyl ether acetate (boiling point: 217 ° C), ethylene glycol Monobutyl ether acetate (boiling point: 188 ° C) and the like.

The (B1) organic solvent formed from the carbonate compound is exemplified by ethyl formate (boiling point: 244 ° C), propyl carbonate (boiling point: 242 ° C), and the like.

(B1) The specific dielectric ratio of the organic solvent is preferably from 13 to 200. By setting the specific dielectric constant of the (B1) organic solvent to the above specific range, the solubility of the [A] polyoxyalkylene of the composition can be improved, and as a result, the coating defect improving property can be improved. Further, the "specific dielectric ratio" means the ratio of the dielectric ratio of the organic solvent to the dielectric ratio of the vacuum. For the specific dielectric constant of the compound, refer to the values described in "Chemical Notes Basics Revision 5". The specific dielectric constant of the compound not described in the above chemical handbook is a value measured at 20 ° C by the method described in JIS C2138.

The (B1) organic solvent having a specific dielectric ratio in the above range is exemplified by a carbonate compound such as ethyl carbonate (specific dielectric ratio: 90) and propylene carbonate (specific dielectric ratio: 63); Alcohol (specific dielectric ratio: 41) and the like.

(B1) The static surface tension of the organic solvent is preferably from 20 mN/m to 50 mN/m. The static surface tension of the (B1) organic solvent is more preferably 20 mN/m or more and 40 mN/m or less, and more preferably 20 mN/m or less and 30 mN/m or less. By setting the static surface tension of the (B1) organic solvent to the above range, the solubility of the [A] polyoxyalkylene of the composition can be improved, and as a result, the coating defect can be improved.

The (B1) organic solvent having a static surface tension in the above range is exemplified by, for example, diethylene glycol monomethyl ether (static surface tension: 29.8 mN/m), triethylene glycol monomethyl ether (static surface tension) :31.9mN/m), Diethylene glycol monoisopropyl ether (static surface tension: 29.9mN/m), ethylene glycol monobutyl ether (static surface tension: 24.0mN/m), diethylene glycol monobutyl ether (static surface tension) :26.2mN/m), triethylene glycol monobutyl ether (static surface tension: 27.7mN/m), ethylene glycol monoisobutyl ether (static surface tension: 22.5mN/m), diethylene glycol single Isobutyl ether (static surface tension: 24.6 mN/m), dipropylene glycol monomethyl ether (static surface tension: 25.1 mN/m), tripropylene glycol monomethyl ether (static surface tension: 25.7 mN/m), two Propylene glycol monopropyl ether (static surface tension: 27.9mN/m), propylene glycol monobutyl ether (static surface tension: 26.8mN/m), dipropylene glycol monobutyl ether (static surface tension: 23.7mN/m), two Ethylene glycol dimethyl ether (static surface tension: 25.3 mN/m), triethylene glycol dimethyl ether (static surface tension: 27.5 mN/m), diethylene glycol methyl ethyl ether (static surface tension) : 24.0 mN/m), diethylene glycol diethyl ether (static surface tension: 23.3 mN/m), diethylene glycol dibutyl ether (static surface tension: 23.6 mN/m), dipropylene glycol dimethyl Ether (static surface tension: 21.1mN/m), diethylene Monoethyl ether acetate (static surface tension: 26.2mN / m) and the like.

The content of the (B1) organic solvent in the solvent is preferably from 1% by mass to 50% by mass, more preferably from 1.5% by mass to 30% by mass, even more preferably from 2% by mass to 20% by mass. . When the content of the (B1) organic solvent in the solvent [B] is in the above range, the storage stability and the coating defect improving property of the composition can be effectively improved.

[(B2) compound)

The (B2) compound is an alkanediol monoalkyl ether acetate compound having a standard boiling point of less than 150.0 °C. The (B2) compound is preferably a propylene glycol monoalkyl ether acetate compound. By making the (B2) compound into the specific compound described above, the solubility of the [A] polyoxane in the [B] solvent of the composition can be further improved, and as a result, the storage stability and the coating defect improvement can be further improved. .

The above (B2) compound is exemplified by, for example, an ethylene glycol monoalkyl ether compound, ethylene glycol monomethyl ether acetate (boiling point: 145 ° C), and the like; as a propylene glycol monoalkyl ether acetate compound, propylene glycol monomethyl Ether acetate (boiling point: 146 ° C) and the like. Among these, propylene glycol monoalkyl ether acetate is preferred, and propylene glycol monomethyl ether acetate is more preferred.

The content of the compound (B2) in the solvent is preferably from 10% by mass to 99% by mass, more preferably from 50% by mass to 99% by mass. By making the content of the (B2) compound in the above range, the solubility of the [A] polyoxane to the [B] solvent can be effectively improved.

[other solvents]

[B] The solvent may also contain (B1) an organic solvent and other solvents other than the (B2) compound (for example, (B1) organic solvent and (B2) compound other than the organic solvent (B3), without impairing the effects of the present invention. ) an organic solvent, or (B4) water, etc.).

The above (B3) organic solvent is exemplified as, for example, an ethylene glycol alkyl ether compound, which is ethylene glycol monomethyl ether (boiling point) : 125 ° C), ethylene glycol monoethyl ether (boiling point: 135 ° C), ethylene glycol monoisopropyl ether (boiling point: 142 ° C), ethylene glycol dimethyl ether (boiling point: 82 ° C), ethylene two Alcohol diethyl ether (boiling point: 121 ° C), etc.; as propylene glycol alkyl ether compound, propylene glycol-1-methyl ether (boiling point: 120 ° C), propylene glycol-1-ethyl ether (boiling point: 133 ° C), propylene glycol 1-propyl ether (boiling point: 149.8 ° C) and the like. Among these, a propylene glycol alkyl ether compound is preferred, more preferably propylene glycol-1-methyl ether, propylene glycol-1-ethyl ether, propylene glycol-1-propyl ether, and more preferably propylene glycol-1-ethyl ether. ether.

The content of the other solvent in the solvent [B] is preferably 70% by mass or less, more preferably 50% by mass or less.

<[C] Acid Diffusion Control Agent>

[C] The acid diffusion controlling agent is a component that controls the diffusion of acid generated in the photoresist film upon exposure. When the composition for forming a resist underlayer film of the present invention further contains a [C] acid diffusion controlling agent, it is possible to effectively suppress acid diffusion of the resist film caused by the resist underlayer film while maintaining the above effects. The shape of the resist pattern formed by the multilayer resist process can be improved. Further, the [C] acid diffusion controlling agent may be used singly or in combination of two or more.

The [C] acid diffusion controlling agent is preferably a nitrogen-containing compound. By making the [C] acid diffusion controlling agent a nitrogen-containing compound, the above diffusion of the composition can be more effectively suppressed, and as a result, the shape of the resist pattern formed by the multilayer resist process can be further improved.

The nitrogen-containing compound is exemplified by, for example, an amine compound, a guanamine-containing compound, a urea compound, a nitrogen-containing heterocyclic compound, and the like.

The above amine compounds are exemplified by, for example, mono(cyclo)alkylamines; di(cyclo)alkylamines; tri(cyclo)alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N,N',N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diamino Diphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis(4-aminophenyl)propane, 2-(3 -aminophenyl)-2-(4-aminophenyl)propane, 2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-aminophenyl) )-2-(4-hydroxyphenyl)propane, 1,4-bis(1-(4-aminophenyl)-1-methylethyl)benzene, 1,3-bis(1-(4- Aminophenyl)-1-methylethyl)benzene, bis(2-dimethylaminoethyl)ether, bis(2-diethylaminoethyl)ether, 1-(2-hydroxyethyl) 2-imidazolidinone, 2-quinoxalinol, N,N,N',N'-indole (2-hydroxypropyl)ethylenediamine, N,N,N',N",N"-five Methyl diethylenetriamine and the like.

The above-mentioned amidino group-containing compound is exemplified by, for example, N-tert-butoxycarbonyl-4-hydroxypiperidine, N-tert-butoxycarbonyl-2-carboxy-4-hydroxypyrrolidine, and N-third butoxide. Amino compound containing a third butoxycarbonyl group such as a carbonylcarbonyl-2-carboxypyrrolidinyl group; an amine compound containing an N-third pentyloxycarbonyl group such as N-third pentyloxycarbonyl-4-hydroxypiperidine N-(9-o-aminobenzylmethyloxycarbonyl)piperidine and other amine-based compounds containing N-(9-o-aminobenzylmethyloxycarbonyl); formamide, N-methyl Formamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, acetamide, benzamide, pyrrolidone, N -methylpyrrolidone, N-ethinyl-1-adamantylamine, and the like.

The above urea compounds are exemplified by, for example, urea, methyl urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenyl. Urea, tri-n-butyl thiourea, and the like.

The above nitrogen-containing heterocyclic compounds are exemplified by, for example, imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinazoline, hydrazine, pyrrolidine, piperidine, piperidine ethanol, 3-(N-piperidin Iridyl)-1,2-propanediol, morpholine, 4-methylmorpholine, 1-(4-morpholinyl)ethanol, 4-ethylmercaptomorpholine, 3-(N-morpholinyl)-1 , 2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, and the like.

Among these, a compound containing a guanamine group is preferred, and an amine compound containing an N-tert-butoxycarbonyl group or an amine compound containing an N-third pentyloxycarbonyl group, preferably N-, is preferred. Third butoxycarbonyl-4-hydroxypiperidine, N-tert-butoxycarbonyl-2-carboxy-4-hydroxypyrrolidine, N-tert-butoxycarbonyl-2-carboxy-pyrrolidine, N- Third pentyloxycarbonyl-4-hydroxypiperidine.

The content of the [C] acid diffusion controlling agent is preferably from 0.1 part by mass to 10 parts by mass, more preferably from 1 part by mass to 5 parts by mass, per 100 parts by mass of the [A] polyoxazane. The shape of the resist pattern can be improved by making the above content in the above range.

<Other optional ingredients>

The composition for forming a resist underlayer film may contain other optional components such as colloidal cerium oxide, colloidal alumina, an organic polymer, and a surfactant. These other optional components may be used alone or in combination of two or more. Further, the content of other optional components may be appropriately selected depending on the purpose thereof.

The above organic polymer is exemplified by, for example, an acrylate compound a polymer such as a methacrylate compound or an aromatic vinyl compound; a vinylamine polymer, a dendrimer, a polyimine, a polyamine, a polyarylenes, a polyamine, a poly Polyquinoxaline, polyoxadiazole, fluorine-based polymer, and the like.

The surfactant is exemplified by, for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a polyoxon surfactant, a polyalkylene oxide surfactant, and a fluorine-containing surfactant. Surfactant and the like.

<Modulation method of composition for forming a resist underlayer film>

The composition for forming a resist underlayer film of the present invention can be prepared by mixing [A] polyoxyalkylene oxide, [B] solvent, an optional [C] acid diffusion controlling agent, other optional components, and the like in a specific ratio.

<Form Formation Method>

The pattern forming method of the present invention has the following steps: (1) a step of forming a resist underlayer film on the substrate to be processed using the composition for forming a resist underlayer film, and (2) using a resist composition in the above-mentioned anti-corrosion a step of forming a resist film on the underlying film, (3) interposing the mask, exposing the resist film by irradiation of the exposed light, and (4) developing the exposed resist film to form an anti-etching film The steps of the etch pattern, and (5) a step of sequentially etching the resist underlayer film and the substrate to be processed by using the resist pattern as a mask.

Since the composition for forming a resist underlayer film has the above properties, it is possible to form a good resist pattern according to the pattern forming method of the present invention.

[step 1)]

In this step, the resist underlayer film forming composition is used to form a resist underlayer film on the substrate to be processed. The substrate to be processed is exemplified by, for example, a tantalum wafer, a wafer coated with aluminum, or the like.

The method for forming the resist underlayer film can be applied to a surface of a substrate to be processed or another underlayer film to be described later, for example, to form a coating film for forming a composition for forming a resist underlayer film, and heating the coating film. It is formed by treatment or hardening by ultraviolet light irradiation and heat treatment. The method of applying the composition for forming a resist underlayer film is, for example, a spin coating method, a roll coating method, a dipping method, or the like. Further, the heating temperature is usually from 50 ° C to 450 ° C, preferably from 150 ° C to 300 ° C. The heating time is usually from 5 seconds to 600 seconds.

Further, another underlayer film (hereinafter also referred to as "other underlayer film") different from the resist underlayer film formed using the composition for forming a resist underlayer film of the present invention may be formed in advance on the substrate to be processed. The other anti-reflection film disclosed in, for example, Japanese Patent Publication No. Hei 6-12452 or JP-A-59-93448.

The film thickness of the above-mentioned resist underlayer film is usually from 10 nm to 1,000 nm, preferably from 10 nm to 500 nm.

[Step (2)]

In this step, a resist film is formed on the resist underlayer film by using a resist composition. Specifically, after the resist composition is applied so that the obtained resist film has a specific film thickness, the solvent in the coating film is volatilized by prebaking to form a resist film.

The resist composition is exemplified by a positive or negative chemically amplified resist composition containing an acid generator, a positive resist composition composed of an alkali-soluble resin and a quinone-based sensitizer, and alkali-soluble. A negative resist composition composed of a resin and a crosslinking agent.

The total solid content concentration of the above resist composition is usually from 1% by mass to 50% by mass. Further, the above-mentioned resist composition is generally filtered by a filter having a pore diameter of, for example, about 0.2 μm, and is provided in the formation of a resist film. Moreover, in this step, the anticorrosive composition of a commercial item can also be used as it is.

The coating method of the resist composition is not particularly limited, and examples thereof include a spin coating method. Further, the prebaking temperature is appropriately adjusted depending on the type of the resist composition to be used, etc., but is usually 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C.

[Step (3)]

In this step, the mask is exposed through exposure of the exposed light. The light to be exposed is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-ray, or the like depending on the type of photoacid generator used in the resist composition. Among these, far ultraviolet rays are preferred, and more preferably KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ excimer laser light (157 nm), Kr ₂ excimer laser light (147 nm), ArKr excimer laser light (134 nm), extreme ultraviolet light (13 nm), and the like. It is preferably an ArKr excimer laser light (wavelength 134 nm).

After the above exposure, post-baking can be performed to improve resolution, pattern profile, development, and the like. The post-baking temperature is appropriately selected depending on the type of the resist composition to be used, etc., but is usually 50 ° C to 200 ° C, preferably 70 ° C to 150 ° C.

[Step (4)]

In this step, the exposed resist film is developed to form a photoresist pattern. The developing liquid used in this step can be appropriately selected depending on the kind of the resist composition to be used. The developing liquid is exemplified by, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethyl ethane. Amine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4 .0] an aqueous alkaline solution such as 7-undecene or 1,5-diazabicyclo-[4.3.0]-5-decene. A water-soluble organic solvent such as an alcohol such as methanol or ethanol or a surfactant may be added to the alkaline aqueous solution in an appropriate amount.

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

[Step 5]

In this step, the resist pattern and the substrate to be processed are sequentially dry-etched by using the resist pattern as a mask. Dry etching can be performed using a conventional dry etching apparatus. In addition, the gas source during dry etching depends on the elemental composition of the object to be etched, and a gas containing oxygen atoms such as O ₂ , CO, CO ₂ , an inert gas such as He, N ₂ or Ar, Cl ₂ or BCl _{4 may be used.} A chlorine-based gas, a fluorine-based gas such as CHF ₃ or CF ₄ , a gas of H ₂ or NH ₃ , or the like. Moreover, these gases can also be used in combination.

Moreover, after the processes, the step of removing the underlying resist film remaining on the substrate to be processed may be provided. Further, the formation of the resist pattern may be a development step without a nanoimprint method or the like.

[Examples]

Hereinafter, the present invention will be more specifically described by examples of the invention, but the invention is not limited to the examples. Further, the measurement of the solid content concentration of the polyoxyalkylene and the weight average molecular weight (Mw) in terms of polystyrene was carried out by the following method.

<solid content concentration of polyoxyalkylene>

0.5 g of the polyoxyalkylene-containing solution was baked at 250 ° C for 30 minutes, and the mass of the obtained solid component was measured to determine the solid content concentration (% by mass) of the polyoxymethane.

<weight average molecular weight (Mw) in terms of polystyrene>

GPC pipe column (G2000HXL: 2, G3000HXL: 1 and G4000HXL: 1) manufactured by TOSOH Co., Ltd., with a flow rate of 1.0 m L/min, dissolution solvent: tetrahydrofuran, column temperature: 40 ° C analysis conditions, using monodisperse polystyrene as a standard, gel permeation chromatography (GPC) to determine the weight average molecular weight (Mw) in terms of polystyrene .

<[A] Synthesis of polyoxyalkylene]

The [A] polyoxane was synthesized using the following decane compound.

M-1: tetramethoxy decane

M-2: Phenyltrimethoxydecane

M-3: 4-methylphenyltrimethoxydecane

M-4: methyltrimethoxydecane

[Synthesis Example 1] (Synthesis of polyoxyalkylene (A-1))

0.55 g of oxalic acid was dissolved in 7.66 g of water to prepare an aqueous oxalic acid solution. Subsequently, (M-1) 12.95 g (60 mol%), (M-2) 5.80 g (30 mol%), (M-3) 3.01 g (10 mol%) and propylene glycol were placed. A cooling tube and a dropping funnel fed with the above aqueous oxalic acid solution were attached to a flask of 70.03 g of 1-ethyl ether. Next, the flask was heated to 60 ° C in an oil bath, and the aqueous oxalic acid solution was slowly added dropwise thereto, followed by a reaction at 60 ° C for 2 hours. After the completion of the reaction, the flask to which the reaction solution was added was allowed to cool, and then placed on a rotary evaporator to remove residual water and methanol formed by the reaction to obtain a solution containing a polyoxane (A-1) as a solid component, 49.2 g. . The solid content concentration of the above solution was 15% by mass, and the Mw of the polyoxyalkylene (A-1) was 1,500.

[Synthesis Example 2] (Synthesis of polyoxyalkylene (A-2))

A solution containing polyoxyalkylene (A-2) was synthesized in the same manner as in Synthesis Example 1, except that various monomers of [A] polyoxyalkylene were used in the amounts shown in Table 1. The solid content concentration and Mw of the obtained solution containing polyoxyalkylene (A-2) are shown in Table 1.

[Synthesis Example 3] (Synthesis of polyoxyalkylene (A-3))

1.28 g of oxalic acid was dissolved in 12.85 g of water by heating to prepare an aqueous oxalic acid solution. Subsequently, a cooling tube was placed on a flask filled with (M-1) 25.05 g (90 mol%), (M-2) 3.63 g (10 mol%), and propylene glycol-1-ethyl ether 57.19 g. A dropping funnel having the above aqueous oxalic acid solution was fed. Next, the flask was heated to 60 ° C in an oil bath, and the aqueous oxalic acid solution was slowly added dropwise thereto, followed by a reaction at 60 ° C for 4 hours. After completion of the reaction, the flask to which the reaction solution was added was allowed to cool, and then attached to a rotary evaporator to remove residual water and methanol, and 97.3 g of a solution containing polyoxyalkylene (A-3) as a solid component was obtained. The solid concentration of the polyoxyalkylene (A-3) of the above solution was 18% by mass, and the Mw of the polyoxyalkylene (A-3) was 2,000.

<Preparation of composition for forming a resist underlayer film>

The components other than [A] polyoxyalkylene are shown below.

[B]solvent (B1) organic solvent

B1-1: ethylene glycol monobutyl ether

(standard boiling point: 171 ° C, static surface tension: 24.0 mN / m)

B1-2: Diethylene glycol diethyl ether

(standard boiling point: 189 ° C, static surface tension: 23.3 mN / m)

B1-3: Diethylene glycol monomethyl ether

(standard boiling point: 194 ° C, static surface tension: 29.8 mN / m)

B1-4: Diethylene glycol monoethyl ether acetate

(standard boiling point: 217 ° C, static surface tension: 26.2 mN / m)

(B2) compound

B2: propylene glycol monomethyl ether acetate (standard boiling point: 146 ° C)

(other solvents)

B3: propylene glycol-1-ethyl ether (standard boiling point: 133 ° C)

B4: Water

[C] acid diffusion control agent

a compound represented by the following formula (C-1) to (C-4)

[Example 1]

1.14 parts by mass of (A-1) of [A] polyoxyalkylene, 4.88 parts by mass of (B1-1) as (B1) organic solvent, and 68.32 parts by mass of (B2) as (B2) compound, as other Solvent (B3) 24.40 parts by mass and (B4) 0.4 parts by mass, and (C-1) 0.06 mass as [C] acid diffusion controlling agent A composition for forming a resist underlayer film is prepared.

[Examples 2 to 12, Comparative Examples 1 to 4]

The composition for forming each of the underlying resist films was prepared in the same manner as in Example 1 except that the types and the amounts of the components to be blended were as described in Table 2. Further, "-" in Table 2 indicates that the component was not formulated.

<evaluation>[n4]

The composition for forming a resist underlayer film prepared as described above was evaluated by the following method. The evaluation results are shown in Table 3.

[Initial coating defect inhibition]

Each of the resist underlayer film forming compositions immediately after preparation is applied onto a tantalum wafer as a substrate to be processed by a spin coating method using a coating/developing device (CLEAN TRACK ACT12, manufactured by Tokyo Electronics Co., Ltd.), and then The obtained film was dried at 220 ° C for 60 seconds, and then cooled to 23 ° C to form a resist underlayer film having a film thickness of 30 nm. Further, the film thickness was measured using an optical film thickness meter (UV-1280SE, manufactured by KLA TENCOL). Subsequently, the coating defect was measured by a surface defect observation apparatus (trade name "KLA2800", manufactured by KLA TENCOL), and the measurement result was used as a coating defect improving property (just after preparation). In this case, when the coating defect was 100 or less, the coating defect improving property (immediately after preparation) was evaluated as "○", and when it was more than 100, it was evaluated as "X".

[Evaluation of preservation stability (1)] (Inhibition of film thickness variation over time)

Each of the resist underlayer film forming compositions was applied onto the surface of the tantalum wafer at a number of revolutions of 2,000 rpm for 20 seconds using a spin coater, followed by drying at 250 ° C for 60 seconds on a hot plate to form respective anti-resistances. The underlying film is etched. The film thickness at the 50-point position was measured for each of the formed resist underlayer films by the optical film thickness meter described above, and the average value was determined as the initial film thickness (T0). In addition, use Each of the resist underlayer film forming compositions was heated at 80 ° C for 5 hours, and each of the resist underlayer films was formed in the same manner as above, and the film thickness was measured, and the average value thereof was determined as the film thickness (T) after storage. Next, the difference (T-T0) between the initial film thickness T0 and the film thickness T after storage is obtained, and the ratio [(T-T0)/T0] of the difference magnitude to the initial film thickness T0 is calculated as the film thickness change rate. When the value is 8% or less, the evaluation is "○", and when it is more than 8% and 10% or less, it is evaluated as "△", and when it is more than 10%, it is evaluated as "X".

[Evaluation of preservation stability (2)] (Time-dependent coating defect inhibition)

After each of the prepared resist underlayer film forming compositions was stored at 40 ° C for one week, each of the compositions after storage was formed in the same manner as the method described in the above "coating defect improving property (just after preparation)". The undercoat film was measured and the coating defect was measured, and the measurement result was used as a coating defect improving property (after storage). In this case, when the coating defect was 100 or less, the coating defect improvement property (after storage) was evaluated as "○", and when it was more than 100, it was evaluated as "X".

As is clear from the results of Table 3, in the examples, the coating defect improving property, the storage stability (the film thickness variation inhibition property over time, and the overcoating defect suppressing property) were all good. On the other hand, in the comparative example, it was found that the coating defect improving property (just after preparation and after storage) was poor.

[Industrial availability]

The present invention provides a composition for forming a resist underlayer film having excellent storage stability and a coating defect improving property capable of suppressing occurrence of coating defects, and a pattern forming method using the composition. According to this, the resistance The composition for forming an underlayer film and the pattern forming method can be preferably used in a manufacturing process of a semiconductor device in which the pattern is miniaturized.

Claims (11)

A composition for forming a resist underlayer film, which comprises a composition for forming a resist underlayer film of [A] polysiloxane and [B] solvent, characterized in that [B] the solvent contains (B1) by the following formula ( 1) a compound or a carbonate compound, and an organic solvent having a normal boiling point of 150.0 ° C or higher, (In the formula (1), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a fluorenyl group having 1 to 4 carbon atoms; R ³ is a hydrogen atom or a methyl group, and n is 1 to 4 An integer, when n is 2 or more, a plurality of R ^{3 's} may be the same or different). The composition for forming a resist underlayer film according to claim 1, wherein the (B1) organic solvent has a normal boiling point of 180 ° C or higher. The composition for forming a resist underlayer film according to claim 1 or 2, wherein the content of the (B1) organic solvent in the [B] solvent is 1% by mass or more and 50% by mass or less. The composition for forming a resist underlayer film according to claim 1, 2 or 3, wherein the (B1) organic solvent has a static surface tension of 20 mN/m or more and 50 mN/m or less. The composition for forming a resist underlayer film according to any one of claims 1 to 4, wherein the [B] solvent further comprises (B2) an alkanediol monoalkyl ether acetate compound having a standard boiling point of less than 150.0 °C. A composition for forming a resist underlayer film according to claim 5, wherein (B2) The alkanediol monoalkyl ether acetate compound is a propylene glycol monoalkyl ether acetate compound. The composition for forming a resist underlayer film according to any one of claims 1 to 6, which is used for a multilayer resist process. The composition for forming a resist underlayer film according to any one of claims 1 to 7, which further comprises a [C] acid diffusion controlling agent. The composition for forming a resist underlayer film according to claim 8, wherein the [C] acid diffusion controlling agent is a nitrogen-containing compound. The composition for forming a resist underlayer film according to any one of claims 1 to 9, wherein [A] polyoxyalkylene is a hydrolysis condensate of a compound containing a decane compound represented by the following formula (i), R ^A _a SiX _4-a (i) (In the formula (i), R ^A is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and a carbon number of 6 to 20 Or an aryl group or a cyano group, a part or all of one of the hydrogen atoms of the above alkyl group may be substituted with an epoxy group, an acid anhydride group or a cyano group, and part or all of the hydrogen atom of the above aryl group may be substituted by a hydroxyl group, X It is a halogen atom or -OR ^B , but R ^B is a monovalent organic group, and a is an integer of 0 to 3. However, when R ^A and X are plural, respectively, the plural R ^A and X may be the same or different. A pattern forming method, comprising the steps of: (1) forming a resist underlayer film on a substrate to be processed, using the composition for forming a resist underlayer film according to any one of claims 1 to 10, (2) a step of forming a resist film on the resist underlayer film using a resist composition, and (3) a step of exposing the resist film by irradiation of exposed light through a mask, (4) The exposed resist film is developed to form a resist pattern, and (5) the step of dry etching the resist underlayer film and the substrate to be processed by using the resist pattern as a mask.