JP5825177B2 - Inorganic film forming composition for multilayer resist process and pattern forming method - Google Patents

Description

  The present invention relates to an inorganic film forming composition for a multilayer resist process and a pattern forming method.

  Along with the miniaturization of semiconductor devices and the like, miniaturization of processing size using a multilayer resist process is progressing in order to obtain a higher degree of integration. In this multilayer resist process, after an inorganic film is formed using a silicon-based inorganic material, a resist composition is further applied to form a resist film that is an organic film having an etching selectivity different from that of the inorganic film, and then by exposure. The mask pattern is transferred and developed with a developer to obtain a resist pattern. Subsequently, this resist pattern is transferred to the inorganic film by dry etching, and finally the pattern of the resist underlayer film is transferred to the substrate to be processed by dry etching, whereby a substrate having a desired pattern is obtained (Japanese Patent Laid-Open No. 2001). -284209, JP2010-85912A, and JP2008-39811A).

  On the other hand, in order to process the substrate to be processed more finely, it is necessary to reduce the thickness of the resist film. However, when a conventional inorganic material such as a silicon oxide film is used to reduce the thickness of the resist film, the resist pattern disappears, loses its shape, bends, and the like, which makes it difficult to transfer a desired pattern.

JP 2001-284209 A JP 2010-85912 A JP 2008-39811 A

  The present invention has been made based on the circumstances as described above, and its purpose is excellent in the formability and etching selectivity of a resist pattern formed on an inorganic film, and is faithful even when the resist film is thinned. To provide an inorganic film forming composition for a multilayer resist process capable of pattern transfer, and a pattern forming method.

The invention made to solve the above problems is
[A] At least one compound selected from the group consisting of a metal compound having a hydrolyzable group, a hydrolyzate of a metal compound having a hydrolyzable group, and a hydrolysis condensate of a metal compound having a hydrolyzable group ,
[B] an organic solvent, and [D] an inorganic film forming composition for a multilayer resist process containing a crosslinking accelerator,
[A] the compound contains at least one metal element selected from the group consisting of Group 6 element, Group 12 element and Group 13 element (hereinafter also referred to as “specific element”), and The content ratio of at least one metal element selected from the group consisting of Group 6 element, Group 12 element and Group 13 element is 50 with respect to the total amount of metal element and metalloid element contained in [A] compound. It is an inorganic film forming composition for multilayer resist processes, characterized by being at least mol%.

  The composition contains the [A] compound, and in addition to setting the content ratio of the specific element in the specific range, the composition contains the [D] cross-linking accelerator, whereby the [A] compound is obtained by a treatment such as heating. As a result, the etching selectivity between the formed inorganic film and the organic film can be improved.

  The composition preferably further contains [C] water. When the composition further contains [C] water, the inorganic film forming reaction can be promoted.

The pattern forming method of the present invention (hereinafter also referred to as “pattern forming method (I)”)
(1) A step of forming an inorganic film on the upper side of the substrate to be processed using the composition;
(2) a step of forming a resist film on the inorganic film using a resist composition;
(3) a step of exposing the resist film by irradiation with radiation through a photomask;
(4) a step of forming a resist pattern by developing the exposed resist film, and (5) a step of forming a pattern on the substrate to be processed by one or more dry etchings using the resist pattern as a mask. Have.

  According to the pattern formation method (I), even when the resist film is thinned, disappearance, shape loss, bending, and the like of the resist pattern can be suppressed, and faithful pattern transfer is possible. Accordingly, the present invention can be suitably applied to pattern formation that requires a finer processing size.

The pattern forming method is:
(0) forming a resist underlayer film on the substrate to be processed;
Further comprising
In the step (1), it is also preferable to form an inorganic film on the resist underlayer film.

  Since the composition provides an excellent etching selectivity between the organic material and the inorganic material, the resist underlayer film having the inorganic film and the organic film is sequentially transferred to the resist pattern using a dry etching process. Can be done.

The resist composition in the step (2) is:
[Α] Polymer having an acid dissociable group that dissociates by the action of an acid (hereinafter, also referred to as “[α] polymer”)
Containing
It is preferable to carry out development in the above step (4) with an organic solvent developer to form a negative resist pattern.

  In this way, with the above-described configuration, the film loss of the resist pattern can be suppressed. As a result, according to the pattern forming method, more faithful pattern transfer is possible.

Another pattern forming method of the present invention (hereinafter also referred to as “pattern forming method (II)”)
(1) A step of forming an inorganic film on the upper side of the substrate to be processed using the composition;
(2 ′) a step of forming a resist pattern on the inorganic film by nanoimprint lithography, and (5) a step of forming a pattern on a substrate to be processed by one or more dry etching using the resist pattern as a mask. Have

The pattern forming method (II) is:
(0) forming a resist underlayer film on the substrate to be processed;
Further comprising
In the step (1), it is also preferable to form an inorganic film on the resist underlayer film.

  According to the pattern formation method (II), faithful pattern transfer is possible through the formation of a resist pattern by the nanoimprint lithography method.

  INDUSTRIAL APPLICABILITY The present invention can provide an inorganic film forming composition for multilayer resist process and a pattern forming method that are excellent in resist pattern formability and etching selectivity. Therefore, in the multilayer resist process using the composition, even when the organic film is thinned, disappearance of the resist pattern, deformation of the shape, bending, and the like can be suppressed, and faithful pattern transfer is possible. Therefore, the present invention can be used very suitably for the manufacture of LSI, which is expected to be further miniaturized in the future, particularly for the formation of fine contact holes and the like.

<Inorganic film forming composition for multilayer resist process>
The inorganic film forming composition for a multilayer resist process of the present invention contains [A] compound, [B] organic solvent and [D] crosslinking accelerator. Moreover, [C] water can be contained as a suitable component. Furthermore, the said composition may contain another arbitrary component, unless the effect of this invention is impaired. The composition can form an inorganic film excellent in the formability of a resist pattern formed on the inorganic film and the resistance to dry etching, and can be suitably used in a multilayer resist process. Hereinafter, each component will be described in detail.

<[A] Compound>
The compound [A] is at least one selected from the group consisting of a metal compound having a hydrolyzable group, a hydrolyzate of a metal compound having a hydrolyzable group, and a hydrolysis condensate of a metal compound having a hydrolyzable group. A kind of compound. [A] The compound contains at least one metal element selected from the group consisting of Group 6 elements, Group 12 elements and Group 13 elements. The content ratio of at least one metal element selected from the group consisting of the Group 6 element, Group 12 element and Group 13 element is the total amount of the metal element and metalloid element contained in the compound [A]. It is 50 mol% or more, 70 mol% or more is preferable and 90 mol% or more is more preferable.

Examples of specific elements include Group 6 elements such as Cr (chromium), Mo (molybdenum), and W (tungsten);
Group 12 elements such as Zn;
Examples include Group 13 elements such as Al (aluminum), Ga (gallium), In (indium), and Tl (thallium).

  Of these specific elements, tungsten and aluminum are preferable. [A] The compound is preferably a metal alkoxide, metal carboxylate or metal complex of the specific element.

[Metal alkoxide]
The said metal alkoxide is a compound which substituted the hydrogen atom of the hydroxyl group which alcohol has with the specific element, and is represented by following formula (1).

In said formula (1), M is an atom of a specific element. a is an integer of 1 to 7 corresponding to the valence of the atom M. R ¹ is an alkyl group having 1 to 10 carbon atoms which may have an alkoxy group, or a cycloalkyl group having 3 to 10 carbon atoms. However, when R ¹ is plural, a plurality of R ¹ may be different even in the same.

  As said alcohol, the compound represented, for example by following formula (2) is preferable.

In said formula (2), R < ² > is synonymous with R < ¹ > in said formula (1).

Examples of the compound represented by the above formula (2) when R ² is an alkyl group or a cycloalkyl group include methanol, ethanol, 1-propanol, 2-propanol, n-butanol, sec-butanol, and pentanol. And cyclohexanol. Examples of the compound represented by the above formula (2) when R ² is an alkyl group substituted with an alkoxy group or a cycloalkyl group include methoxymethanol, methoxyethanol, ethoxymethanol, ethoxyethanol, methoxypropanol, ethoxy Examples include propanol and propoxypropanol.

[Metal carboxylate]
The said metal carboxylate is a compound which substituted the hydrogen atom of the carboxy group which carboxylic acid has with the specific element, and is represented by following formula (3).

In said Formula (3), M and a are synonymous with the said Formula (1). R ³ is an organic group. However, if R ³ is plural, the plurality of R ³ may be be the same or different.

  As said carboxylic acid, the compound represented, for example by following formula (4) is preferable.

In said formula (4), R < ⁴ > is synonymous with R < ³ > in said formula (3).

  Examples of the compound represented by the above formula (4) include acetic acid, trifluoroacetic acid, 2-methylpropanoic acid, pentanoic acid, 2,2-dimethylpropanoic acid, butanoic acid, hexanoic acid, 2-ethylhexanoic acid, and octane. Examples include acid, nonanoic acid, decanoic acid, acrylic acid, methacrylic acid, and salicylic acid.

[Metal complex]
The metal complex is a compound in which a hydrolyzable group is bonded to an atom of a specific element, and examples thereof include those represented by the following formula (5).

In the above formula (5), M and ^{R 1} is as defined in the above formula (1). R ³ has the same meaning as the above formula (3). b and c are each independently an integer of 0 to 7. However, b + c corresponds to the valence of atom M. d is an integer of 0-7. R ⁵ is an organic compound. However, when R ⁵ is plural, the plurality of R ⁵ may be the same or different.

Examples of the organic compound represented by R ⁵ include ethers represented by the following formula (6).

In said formula (6), R < ⁶ > and R < ⁷ > is a C1-C10 saturated or unsaturated hydrocarbon group which may have an oxygen atom in a frame chain. However, R ⁶ and R ⁷ may be bonded to each other to form a ring structure.

  Examples of the ethers represented by the above formula (6) include methylal, diethyl ether, dipropyl ether, dibutyl ether, diamyl ether, diethyl acetal, dihexyl ether, trioxane, dioxane and the like.

Examples of the organic compound represented by R ⁵ include ketones represented by the following formula (7) or formula (8).

In the above formulas (7) and (8), R ⁸ and R ¹⁰ are each independently a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms which may have a keto group in the skeleton chain. is there. R ⁹ and R ¹¹ are each independently a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms.

  Examples of the ketones represented by the above formula (7) or (8) include acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl cyclohexyl ketone, diethyl ketone, ethyl butyl ketone, trimethylnonanone, Acetonylacetone, mesityl oxide, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), acetylacetone (2,4-pentanedione), 2,4-trifluoropentanedione, 2,4- Hexafluoropentanedione, ethyl acetoacetate, 2,2,6,6-tetramethyl-3,5-heptanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, etc. Is mentioned.

Examples of the organic compound represented by R ⁵ include esters represented by the following formula (9).

In said formula (9), R < ¹⁴ > is a C1-C10 saturated or unsaturated hydrocarbon group which may have a keto group, a hydroxy group, or an alkoxy group. R ¹⁵ is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms which may have an alkoxy group.

  Examples of the esters represented by the above formula (9) include ethyl formate, methyl acetate, ethyl acetate, butyl acetate, cyclohexyl acetate, methyl propionate, ethyl butyrate, ethyl oxyisobutyrate, ethyl acetoacetate, ethyl lactate, methoxybutyl. Examples include acetate, diethyl oxalate, and diethyl malonate.

  The hydrolyzate is obtained by hydrolyzing the [A] compound. The hydrolysis condensate may condense only the [A] compound, or may condense the [A] compound with another compound. The content ratio of the specific element in the hydrolysis condensate is 50 mol% or more, preferably 70 mol% or more, with respect to the total amount of the metal elements and metalloid elements contained in the hydrolysis condensate, More preferably, it is 90 mol% or more. Hydrolysis is performed by adding water or water and a catalyst to the [A] compound and stirring at 20 ° C. to 100 ° C. for several hours to several days. As usage-amount of water, it is 100 mol or less normally with respect to 100 mol of [A] compounds, Preferably it is 5-50 mol. Examples of the catalyst include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; acid catalysts such as organic acids such as acetic acid, propionic acid, butyric acid and maleic acid, sodium hydroxide, potassium hydroxide, ammonia, monoethanolamine, diethanolamine, Examples thereof include inorganic or organic alkali catalysts such as tetramethylammonium hydroxide.

<[B] Organic solvent>
In the present invention, the composition can be obtained by dissolving or dispersing the [A] compound and [D] crosslinking accelerator in the [B] organic solvent. [B] Examples of the organic solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and mixed solvents thereof. These solvents may be used alone or in combination of two or more.

Examples of alcohol solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol ether solvents such as dipropylene glycol monopropyl ether.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl iso-butyl ketone, methyl n-pentyl ketone, ethyl n-butyl ketone, methyl n-hexyl ketone, and diiso-. Examples include ketone solvents such as butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, and acetophenone.

  Examples of the amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like can be mentioned.

  Examples of the ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, acetic acid. n-pentyl, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, acetoacetate Ethyl acetate ethylene glycol monomethyl ether, acetate ethylene glycol monoethyl ether, acetate diethylene glycol monomethyl ether, acetate diethylene glycol monoethyl ether, acetate diethylene glycol mono-n-butyl Ether ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriacetate Glycol, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, Examples thereof include dimethyl phthalate and diethyl phthalate.

  Of these [B] organic solvents, propylene glycol monomethyl ether and propylene glycol monoethyl ether are preferred.

  [B] As the content of the organic solvent, the content of the [A] compound in the composition is 0.5% by mass to 20% by mass, preferably 0.5% by mass to 15% by mass in terms of metal oxide. % Content is preferred.

<[D] Cross-linking accelerator>
[D] The crosslinking accelerator is a compound that generates an acid or a base by light or heat. When the composition contains [D] a crosslinking accelerator, the etching selectivity between the inorganic film and the organic film is improved. [D] Examples of the crosslinking accelerator include onium salt compounds and N-sulfonyloxyimide compounds. [D] The crosslinking accelerator is preferably a thermal crosslinking accelerator that generates an acid or a base by heat, and among them, an onium salt compound is preferable.

  Examples of the onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, ammonium salts, and the like.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro- n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept- -Yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium par Fluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylphosphonium 1,1, Examples include 2,2-tetrafluoro-6- (1-adamantane carbonyloxy) -hexane-1-sulfonate.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Nitro 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (6-n-butoxynaphthalene-2 Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene- 2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium perfluoro-n-octance Phonates, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, etc. Can be mentioned.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t -Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Le Oro ethanesulfonate.

  Examples of ammonium salts include ammonium formate, ammonium maleate, ammonium fumarate, ammonium phthalate, ammonium malonate, ammonium succinate, ammonium tartrate, ammonium malate, ammonium lactate, ammonium citrate, ammonium acetate, ammonium propionate, Ammonium butanoate, ammonium pentanoate, ammonium hexanoate, ammonium heptanoate, ammonium octanoate, ammonium nonanoate, ammonium decanoate, ammonium oxalate, ammonium adipate, ammonium sebacate, ammonium butyrate, ammonium oleate, ammonium stearate , Ammonium linoleate, ammonium linolenate, ammonium salicylate, benze Ammonium sulfonate, ammonium benzoate, ammonium p- aminobenzoic acid, ammonium p- toluenesulfonic acid, ammonium methanesulfonate, ammonium trifluoromethanesulfonate, ammonium trifluoroethane sulfonic acid and the like. In addition, the ammonium ion of the above ammonium salt is methylammonium ion, dimethylammonium ion, trimethylammonium ion, tetramethylammonium ion, ethylammonium ion, diethylammonium ion, triethylammonium ion, tetraethylammonium ion, propylammonium ion, dipropylammonium ion Ion, tripropylammonium ion, tetrapropylammonium ion, butylammonium ion, dibutylammonium ion, tributylammonium ion, tetrabutylammonium ion, trimethylethylammonium ion, dimethyldiethylammonium ion, dimethylethylpropylammonium ion, methylethylpropylbutylammonium Ion, triethanolammonium ion, diethanolammonium ion, ammonium salt substituted on the triethanolammonium ions, and the like. Furthermore, 1,8-diazabicyclo [5.4.0] undec-7-ene salt, 1,5-diazabicyclo [4.3.0] -5-nonene salt and the like can be mentioned. As the 1,8-diazabicyclo [5.4.0] undec-7-ene salt, 1,8-diazabicyclo [5.4.0] undec-7-ene formate, 1,8-diazabicyclo [5.4. 0] Undeca-7-ene p-toluenesulfonic acid and the like.

  Examples of the N-sulfonyloxyimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy). ) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept- 5-ene-2,3-dicarboximide and the like can be mentioned.

  Among these [D] crosslinking accelerators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, tetraalkylammonium salt, , 8-diazabicyclo [5.4.0] undec-7-ene salt.

  These [D] crosslinking accelerators may be used alone or in combination of two or more. [D] As a usage-amount of a crosslinking accelerator, 10 mass parts or less are preferable with respect to 100 mass parts of [A] compounds, and 0.1 mass part or more and 5 mass parts or less are more preferable. [D] By making the usage-amount of a crosslinking accelerator into the said specific range, an etching selectivity can be improved.

<[C] water>
The composition preferably further contains [C] water as a suitable component. When the composition further contains [C] water, the inorganic film forming reaction can be promoted. [C] Water is not particularly limited, and examples thereof include distilled water and ion exchange water. [C] The content of water is preferably 0.1 part by mass to 10 parts by mass and more preferably 1 part by mass to 8 parts by mass with respect to 100 parts by mass of the composition.

<Other optional components>
The said inorganic film formation composition can contain other arbitrary components, such as surfactant, in the range which does not impair the effect of this invention.

[Surfactant]
A surfactant is a component that exhibits an effect of improving coatability, striation and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. In addition to nonionic surfactants such as stearate, the following trade names are KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac F171, F173 (above, manufactured by Dainippon Ink & Chemicals), Fluorad FC430, FC431 ( As above, manufactured by Sumitomo 3M, Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, manufactured by Asahi Glass) ) And the like.

  Surfactants may be used alone or in combination of two or more. Moreover, the compounding quantity of surfactant can be suitably determined according to the objective.

<Preparation method of inorganic film forming composition for multilayer resist process>
The composition can be prepared, for example, by mixing [A] compound, [C] water, [D] cross-linking accelerator, and other optional components at a predetermined ratio in [B] organic solvent. The composition is usually prepared by dissolving in a solvent upon use and then filtering with a filter having a pore size of about 0.2 μm, for example.

<Pattern Forming Method (I)>
The pattern forming method (I) of the present invention comprises:
(1) A step of forming an inorganic film on the upper side of the substrate to be processed using the composition;
(2) a step of forming a resist film on the inorganic film using a resist composition;
(3) a step of exposing the resist film by irradiation with radiation through a photomask;
(4) a step of forming a resist pattern by developing the exposed resist film, and (5) a step of forming a pattern on the substrate to be processed by one or more dry etchings using the resist pattern as a mask. Have.

  According to the pattern formation method (I), even when the resist film is thinned, disappearance, shape loss, bending, and the like of the resist pattern can be suppressed, and faithful pattern transfer is possible. Accordingly, the present invention can be suitably applied to pattern formation that requires a finer processing size.

The pattern forming method is
(0) forming a resist underlayer film on the substrate to be processed;
Further comprising
In the step (1), an inorganic film is preferably formed on the resist underlayer film.

The resist composition in the step (2) is:
[Α] containing a polymer having an acid dissociable group that dissociates by the action of an acid,
It is preferable to perform development in the step (4) with an organic solvent developer to form a negative resist pattern.

  Since the composition provides an excellent etching selectivity between the organic material and the inorganic material, the resist underlayer film that is the inorganic film and the organic film is sequentially transferred to the resist pattern using a dry etching process. Can be done. Hereinafter, each process is explained in full detail.

[Step (1)]
In this step, an inorganic film is formed on the upper side of the substrate to be processed using the composition. Examples of the substrate to be processed include insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, and commercially available products such as black diamond (manufactured by AMAT), silk (manufactured by Dow Chemical), LKD5109 (manufactured by JSR), and the like. An interlayer insulating film such as a wafer coated with a low dielectric insulating film. As the substrate to be processed, a patterned substrate such as a wiring course (trench) or a plug groove (via) may be used. As a method for forming the inorganic film, a coating film of the composition is formed by coating on the surface of a substrate to be processed, and the coating film is cured by heat treatment, or irradiation with ultraviolet light and heat treatment. Can be formed. Examples of the method for applying the composition include spin coating, roll coating, and dipping. Moreover, as heating temperature, it is 150 to 500 degreeC normally, Preferably it is 180 to 350 degreeC. The heating time is usually 30 seconds to 1,200 seconds, preferably 45 seconds to 600 seconds. Furthermore, ultraviolet light irradiation may be performed after application of the composition. The film thickness of the inorganic film is usually about 5 nm to 50 nm.

[Step (0)]
Moreover, you may have the process of forming a resist underlayer film on a to-be-processed substrate before the said process (1). Examples of the resist underlayer film include an organic film formed using a resist underlayer film composition and a carbon film formed by a conventionally known CVD (Chemical Vapor Deposition) method. As the resist underlayer film forming composition, conventionally known compositions can be used, and examples thereof include NFC HM8005 (manufactured by JSR). As a method for forming the resist underlayer film, a coating film of the resist underlayer film forming composition is formed by coating on a substrate to be processed, and this coating film is subjected to heat treatment, or irradiation with ultraviolet light and heat treatment. It can be formed by curing. Examples of the method for applying the resist underlayer film forming composition include spin coating, roll coating, and dipping. Moreover, as heating temperature, it is 150 to 500 degreeC normally, Preferably it is 180 to 350 degreeC. The heating time is usually 30 seconds to 1,200 seconds, preferably 45 seconds to 600 seconds. The thickness of the resist underlayer film is usually about 50 nm to 500 nm.

In addition, another lower layer film different from the resist lower layer film obtained by using the resist lower layer film forming composition may be formed on the surface of the substrate to be processed. The other lower layer film is a film provided with an antireflection function, coating film flatness, high etching resistance against a fluorine-based gas such as CF _{4, and the} like. As other lower layer films, for example, commercially available products such as NFC HM8005 (manufactured by JSR) can be used.

[Steps (2) to (4)]
In steps (2) to (4), a resist composition is applied on the inorganic film, and exposed, heated, and developed to form a resist pattern. As the resist composition, for example, a chemically amplified resist composition containing an acid generator and having an exposed portion soluble in an alkaline water-soluble developer and hardly soluble in an organic solvent developer. A chemically amplified resist composition having an acid generator and a crosslinking agent, and the exposed portion is hardly soluble in an alkali water-soluble developer, an organic solvent developer, an alkali-soluble resin, and a quinonediazide-based photosensitive agent. However, resist compositions that are soluble in an alkaline water-soluble developer may be used. Among these resist compositions, a chemically amplified resist composition containing an acid generator and having an exposed portion that is soluble in an alkaline water-soluble developer and hardly soluble in an organic solvent developer. Is preferred.

  The resist coating film is formed by volatilizing a solvent (that is, a solvent contained in the resist composition) in the coating film by pre-baking the coating film formed by applying the resist composition. Can do. The pre-baking temperature is appropriately adjusted according to the type of resist composition to be used, but is preferably 30 ° C to 200 ° C, more preferably 50 ° C to 150 ° C. The heating time is usually 30 seconds to 200 seconds, preferably 45 seconds to 120 seconds. In addition, you may provide another coating film on the surface of this resist film. The film thickness of the resist film is usually 1 nm to 500 nm, preferably 10 nm to 300 nm.

Next, the resulting resist coating film is selectively irradiated with radiation through a photomask to expose the resist coating film. The radiation is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, γ-ray, molecular beam, ion beam, etc., depending on the type of acid generator used in the resist composition. Is preferably far ultraviolet rays, and KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (wavelength 157 nm), Kr ₂ excimer laser (wavelength 147 nm), ArKr excimer laser (wavelength 134 nm), Extreme ultraviolet rays (wavelength 13.5 nm, etc.) are more preferable. Further, an immersion exposure method can also be employed. The immersion upper layer film may be formed on the resist film using the immersion upper layer film forming composition.

  Post-exposure baking (PEB) is performed to improve the resolution, pattern profile, developability, and the like of the resist film after exposure. The temperature of the PEB is appropriately adjusted according to the type of resist composition used, but is preferably 180 ° C. or lower, and more preferably 150 ° C. or lower. The heating time is usually 30 seconds to 200 seconds, preferably 45 seconds to 120 seconds.

  After PEB, the resist coating film is developed to form a resist pattern. The developer used for development can be appropriately selected depending on the type of resist composition used. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia water, primary amines such as ethylamine and n-propylamine, diethylamine, and di-n-propylamine Secondary amines, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, quaternary compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine and choline Alkaline aqueous solutions such as ammonium salts, cyclic amines such as pyrrole and piperidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene Can be mentioned. These alkaline aqueous solutions may be those obtained by adding an appropriate amount of a water-soluble organic solvent, for example, alcohols such as methanol and ethanol, and a surfactant.

  Examples of the organic solvent developer include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

As the alcohol solvent, for example,
Monoalcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol;
Polyhydric alcohol solvents such as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol;
Polyhydric alcohol partial ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether System solvents and the like.

As the ether solvent, for example,
Dialiphatic ethers such as dipropyl ether and dibutyl ether; diaromatic ethers such as diphenyl ether and ditolyl ether;
Examples thereof include aromatic-aliphatic ethers such as anisole and phenylethyl ether.

Examples of the ketone solvent include:
Acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl amyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone, trimethyl Aliphatic ketone solvents such as nonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone;
Aliphatic-aromatic ketone solvents such as acetophenone, propiophenone, tolylmethylketone;
Aromatic ketone solvents such as benzophenone, tolylphenyl ketone, and ditolyl ketone are listed.

As the amide solvent, for example,
N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N -Methylpyrrolidone and the like.

As the ester solvent, for example,
Methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, propion Monoester solvents such as iso-amyl acid, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate;
Diester solvents such as glycol diacetate, diethyl oxalate, di-n-butyl oxalate, diethyl malonate, dimethyl phthalate and diethyl phthalate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol monoether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Lactone solvents such as γ-butyrolactone and γ-valerolactone;
Examples thereof include carbonate solvents such as diethyl carbonate, dipropyl carbonate, ethylene carbonate, and propylene carbonate.

Examples of the hydrocarbon solvent include
Aliphatic carbonization such as n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, methylcyclohexane A hydrogen-based solvent;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents and the like.

  Of these, ether solvents, ketone solvents, and ester solvents are preferred. As the ether solvent, an aromatic-aliphatic ether solvent is more preferable, and anisole is more preferable. As the ketone solvent, an aliphatic ketone solvent is more preferable, and methyl amyl ketone is more preferable. As the ester solvent, a monoester solvent is more preferable, and butyl acetate is more preferable. These organic solvents may be used individually by 1 type, and may use 2 or more types together.

  The content of the organic solvent in the organic solvent developer is 80% by mass or more, preferably 100%. By setting the content of the organic solvent in the developer to 80% by mass or more, the contrast of the pattern depending on the presence or absence of exposure can be improved. As a result, a pattern having excellent development characteristics and lithography characteristics can be formed. it can. In addition, a basic compound such as amines can be added to the organic solvent developer for the purpose of adjusting the solubility of the exposed portion in the developer. It is preferable to wash the resist pattern with a rinsing solution after development.

[Step (5)]
In this step, a pattern is formed on the substrate to be processed by dry etching one or more times using the resist pattern as a mask. When the resist underlayer film is formed, the inorganic film, the resist underlayer film, and the substrate to be processed are sequentially dry-etched using the resist pattern as a mask to form a pattern. Dry etching can be performed using a known dry etching apparatus. The source gas during dry etching depends on the elemental composition of the object to be etched, but includes oxygen atoms such as O ₂ , CO, and CO ₂ , inert gases such as He, N ₂ , and Ar, Cl ₂ , chlorine gas such as BCl ₃ , fluorine gas such as CHF ₃ and CF ₄ , gas of H ₂ and NH ₃ , etc. can be used. In addition, these gases can also be mixed and used.

The resist composition in the step (2) is:
[Α] a polymer having an acid dissociable group that is dissociated by the action of an acid, and [β] an acid generator,
It is preferable to perform development in the step (4) with an organic solvent developer to form a negative resist pattern. The resist composition may contain a polymer other than the [α] polymer.

[[Α] polymer]
The [α] polymer is a polymer having an acid dissociable group that is dissociated by the action of an acid. As long as the [α] polymer is a polymer having an acid dissociable group that dissociates by the action of an acid, the specific structure is not particularly limited. For example, the polymer is represented by the following formula (10). It is preferable to have a structural unit (I) containing an acid dissociable group.

In said formula (10), ^Rp is an acid dissociable group.

  When the structural unit (I) has a group represented by the above formula (10), the solubility of the exposed portion of the resist film used in the pattern forming method in the developing solution can be reduced. Reduction can be suppressed.

  The structural unit (I) is preferably a structural unit represented by the following formula (11).

In said formula (11), R <^16> is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ^p has the same ^{meaning as} in the above formula (10).

  When the structural unit (I) has the above specific structure, the solubility of the resist film used in the pattern forming method in the exposed portion of the developing solution can be further reduced, and the film loss in the exposed portion can be further suppressed. it can.

The acid dissociable group represented by R ^p is preferably represented by the following formula (12).

In said formula (12), R ^<p1 > -R <^p3> is a C1-C4 alkyl group or a C4-C20 alicyclic hydrocarbon group. However, one part or all part of the hydrogen atom which the said alkyl group and alicyclic hydrocarbon group have may be substituted. R ^p2 and R ^p3 may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atoms to which R ^p2 and R ^p3 are bonded.

By making the acid dissociable group represented by R ^p in the above formulas (10) and (11) into a group having a specific structure represented by the above formula (12), the acid dissociable group is It is easily dissociated by the action of the generated acid. As a result, according to the pattern forming method, the solubility of the exposed portion of the resist film in the developing solution can be further reduced, and film loss can be further suppressed.

[[Β] acid generator]
The [β] acid generator generates an acid upon exposure and changes the solubility of the [α] polymer in the developer by, for example, dissociating an acid-dissociable group present in the [α] polymer. .

Examples of the [β] acid generator include onium salt compounds, N-sulfonyloxyimide compounds, halogen-containing compounds, diazoketone compounds, and the like.

Examples of the onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  Of these, onium salt compounds are preferred, sulfonium salts are more preferred, and triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate, triphenylsulfonium 2- (1- More preferred is adamantyl) -1,1-difluoroethanesulfonate. One or more [β] acid generators may be used.

  The content when the [β] acid generator is an acid generator is usually from 0 to 100 parts by mass of the [α] polymer from the viewpoint of ensuring the sensitivity and developability of the resist composition. 1 to 20 parts by mass, preferably 0.5 to 15 parts by mass.

  When the development in the step (4) is carried out with an organic solvent developer to form a negative resist pattern, the organic solvent is selected from the group consisting of ether solvents, ketone solvents and ester solvents. Preferably, it is at least one organic solvent. Thereby, the solubility with respect to the developing solution of an exposure part can further be reduced, and film | membrane reduction can further be suppressed.

<Pattern formation method (II)>
The pattern forming method (II) of the present invention comprises:
(1) A step of forming an inorganic film on the upper side of the substrate to be processed using the composition;
(2 ′) a step of forming a resist pattern on the inorganic film by nanoimprint lithography, and (5) a step of forming a pattern on a substrate to be processed by one or more dry etching using the resist pattern as a mask. Have

The pattern forming method (II) is:
(0) forming a resist underlayer film on the substrate to be processed;
Further comprising
In the step (1), an inorganic film is preferably formed on the resist underlayer film.

  According to the pattern formation method, it can be suitably applied also by a nanoimprint lithography method. The description in the above-mentioned pattern formation method (I) can be applied to the step (0), the step (1) and the step (5) of the pattern formation method (II). Hereinafter, the step (2 ′) will be described in detail.

[Step (2 ′)]
Step (2 ′) is a step of forming a resist pattern on the inorganic film by nanoimprint lithography. This resist pattern can be formed using, for example, a radiation-sensitive curable composition. Specifically, the pattern forming layer is formed by applying a radiation-sensitive curable composition on the substrate on which the inorganic film has been formed in the step (1), and the surface of the mold having the reverse pattern on the surface is hydrophobic. A step of pressurizing the surface of the mold subjected to the hydrophobic treatment, a step of pressing the surface of the mold against the pattern forming layer, a step of exposing the pattern forming layer in a state of pressing the mold, and an exposed pattern forming layer of the mold. And a step of peeling from the substrate.

  In this case, the said curable composition can contain a hardening accelerator etc. Examples of the curing accelerator include a radiation-sensitive curing accelerator and a thermosetting accelerator. Among these, a radiation sensitive curing accelerator is preferable. The radiation-sensitive curing accelerator can be appropriately selected depending on the structural unit constituting the radiation-sensitive composition for nanoimprint, and examples thereof include a photoacid generator, a photobase generator, and a photosensitizer. In addition, a radiation sensitive hardening accelerator may use 2 or more types together.

  Examples of the coating method include an inkjet method, a dip coating method, an air knife coating method, a curtain coating method, a wire barcode method, a gravure coating method, an extrusion coating method, a spin coating method, and a slit scanning method.

  In the hydrophobic treatment process of the mold, the surface of the mold having a reverse pattern on the surface is subjected to a hydrophobic treatment with a release agent or the like. The mold needs to be made of a light transmissive material. Examples of the light transmissive material include a light transparent resin such as glass, quartz, PMMA, and polycarbonate resin; a transparent metal vapor deposited film; a flexible film such as polydimethylsiloxane; a photocured film; and a metal film.

  Examples of the release agent include a silicon release agent, a fluorine release agent, a polyethylene release agent, a polypropylene release agent, a paraffin release agent, a montan release agent, and a carnauba release agent. Is mentioned. In addition, a mold release agent may be used independently and may use 2 or more types together. Of these, silicon-based release agents are preferred. Examples of the silicon release agent include polydimethylsiloxane, acrylic silicone graft polymer, acrylic siloxane, and arylsiloxane.

  The pressing process is a process of pressing the hydrophobically treated mold onto the pattern forming layer. A mold concavo-convex pattern is formed in the pattern forming layer by pressing a mold having the concavo-convex pattern onto the pattern forming layer. The pressure at the time of pressing the mold is usually 0.1 MPa to 100 MPa, preferably 0.1 MPa to 50 MPa, and more preferably 0.1 MPa to 30 MPa. The pressing time is usually 1 second to 600 seconds, preferably 1 second to 300 seconds, and more preferably 1 second to 180 seconds.

  In the exposure step, the pattern forming layer is exposed while the mold is pressed. By exposing the pattern forming layer, radicals are generated from the photopolymerization initiator contained in the radiation-sensitive composition for nanoimprinting. Thereby, the pattern formation layer which consists of a radiation sensitive composition for nanoimprint hardens | cures in the state which the uneven | corrugated pattern of the mold was transcribe | transferred. By transferring the concavo-convex pattern, it can be used, for example, as a film for an interlayer insulating film of a semiconductor element such as LSI, system LSI, DRAM, SDRAM, RDRAM, or D-RDRAM, a resist film or the like when manufacturing the semiconductor element.

  In addition, when a curable composition is thermosetting, it is hardened by a heat curing process instead of the said exposure process. When thermosetting is performed, the heating atmosphere and the heating temperature are not particularly limited. For example, heating can be performed at 40 ° C. to 200 ° C. under an inert atmosphere or under reduced pressure. Heating can be performed using a hot plate, oven, furnace, or the like.

  Finally, the mold is peeled from the pattern forming layer. The peeling method is not particularly limited. For example, the base material may be fixed and the mold may be moved away from the base material, or the mold may be fixed and the base material may be moved away from the mold to be peeled off. Alternatively, both of them may be peeled by pulling in the opposite direction.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<[A] Compound>
The [A] compounds used in the synthesis examples, examples and comparative examples are as follows.
A-1: Tungsten (V) ethoxide A-2: Bis (2,4-pentanedionate) zinc A-3: Aluminum (III) 2,4-pentanedionate A-4: Indium (III) 2,4 -Pentandionate A-5: Tetramethoxysilane A-6: Titritrimethoxysilane A-7: Phenyltrimethoxysilane

[Synthesis Example 1]
30.00 g of the above (A-1) and 60.00 g of propylene glycol monomethyl ether (PGME) were mixed and stirred at 25 ° C. for 10 minutes, then mixed with 10.00 g of water, heated to 60 ° C. and heated for 4 hours. Heating and stirring were performed. After completion of the reaction, the reaction mixture was cooled to room temperature, 30.00 g of propylene glycol monomethyl ether was added, and the low boiling point product was removed by an evaporator to obtain a solution of hydrolysis condensate (A-8). The solid content concentration of the solution (A-8) was 10.98% as a result of measurement by a firing method.

[Synthesis Examples 2 to 5]
Hydrolysis condensates (A-9) to (A-12) were synthesized in the same manner as in Synthesis Example 1 except that the types and amounts of the components shown in Table 1 were used.

[Synthesis Example 6]
An aqueous oxalic acid solution was prepared by dissolving 0.40 g of oxalic acid in 19.20 g of water by heating. A dropping funnel containing the cooling pipe and the prepared aqueous oxalic acid solution in a flask containing 9.46 g of (A-5), 3.02 g of (A-6), 0.88 g of (A-7) and PGME 67.04 g. And set. Subsequently, after heating to 60 degreeC with an oil bath, the oxalic acid aqueous solution was dripped slowly, and it was made to react at 60 degreeC for 4 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then set in an evaporator, and low-boiling substances were removed with an evaporator to obtain a solution of hydrolysis condensate (A-13). The solid content concentration of the solution (A-13) was 11.90% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 2,900.

<Preparation of inorganic film forming composition for multilayer resist process>
[B] Organic solvents and [D] cross-linking accelerators used in Examples and Comparative Examples are as follows.

<[B] Organic solvent>
B-1: Propylene glycol monomethyl ether B-2: Propylene glycol monoethyl ether

<[D] Cross-linking accelerator>
D-1: Diphenyliodonium trifluoromethanesulfonate D-2: 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate D-3: Tetramethylammonium acetate D-4: 1,8- Diazabicyclo [5.4.0] undec-7-ene p-toluenesulfonate

[Example 1]
[A] After dissolving 17.34 parts by mass of (A-8) as a compound in 46.50 parts by mass of (B-1) and (B-2) 31.06 parts by weight of [B] organic solvent , (C) 5.00 parts by mass, (D-2) 0.10 parts by mass, and then filtering this solution through a filter having a pore size of 0.2 μm to prepare an inorganic film forming composition for a multilayer resist process did.

[Examples 2 to 5 and Comparative Example 1]
Each inorganic film forming composition of the multilayer resist process was prepared in the same manner as in Example 1 except that each type and amount of components shown in Table 2 were used. “-” Indicates that the corresponding component was not used.

<Evaluation>
Various physical properties of each inorganic film forming composition of the multilayer resist process prepared as described above were evaluated as follows. The results are shown in Table 2.

[Resist pattern formability, alkaline aqueous solution development]
A resist underlayer film forming composition (NFC HM8005, manufactured by JSR) is applied onto a silicon wafer as a substrate to be processed by a spin coater, and dried on a hot plate at 250 ° C. for 60 seconds to thereby form a resist underlayer having a film thickness of 300 nm. A film was formed. Each inorganic film forming composition was applied onto the formed resist underlayer film by a spin coater and baked on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a thickness of 20 nm. A resist composition (ARX2014J, manufactured by JSR) was applied on the formed inorganic film and dried at 90 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. A liquid immersion upper layer film-forming composition (NFC TCX091-7, manufactured by JSR) was applied on the formed resist film and dried at 90 ° C. for 60 seconds to form a liquid immersion upper layer film having a film thickness of 30 nm. Thereafter, using an ArF excimer laser irradiation apparatus (S610C, manufactured by Nikon Corporation), the substrate was heated at 115 ° C. for 60 seconds after exposure treatment with a laser irradiation amount of 16 mJ / cm ² by a liquid immersion method. Next, the resist pattern was developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 30 seconds to form a resist pattern having a 50 nm line and space pattern in which the resist remaining on the silicon wafer and the width of the resulting groove were 50 nm each. Formed. The formed resist pattern is observed with a scanning electron microscope (manufactured by Hitachi High-Tech), and the resist pattern formability is good when the bottom shape of the resist pattern does not become a flared shape in a 50 nm line and space pattern (A ) And the case where the skirt spreads out is judged as poor (B) in resist pattern formability. Pattern transfer was performed by sequentially dry-etching the inorganic film and the substrate to be processed using the formed resist pattern as a mask using a dry etching apparatus (Telius SCCM, manufactured by Tokyo Electron).

[Resist pattern formability, organic solvent development]
A resist underlayer film forming composition (NFC HM8005, manufactured by JSR) is applied onto a silicon wafer as a substrate to be processed by a spin coater, and dried on a hot plate at 250 ° C. for 60 seconds to thereby form a resist underlayer having a film thickness of 300 nm. A film was formed. Each inorganic film forming composition was applied onto the formed resist underlayer film by a spin coater and baked on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a thickness of 20 nm. A resist composition was applied on the formed inorganic film and dried at 90 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. A liquid immersion upper layer film-forming composition (NFC TCX091-7, manufactured by JSR) was applied on the formed resist film and dried at 90 ° C. for 60 seconds to form a liquid immersion upper layer film having a film thickness of 30 nm. Thereafter, using an ArF excimer laser irradiation apparatus (S610C, manufactured by Nikon Corporation), the substrate was heated at 115 ° C. for 60 seconds after exposure treatment with a laser irradiation amount of 16 mJ / cm ² by a liquid immersion method. Next, paddle development (30 seconds) was performed using butyl acetate as a developer, and rinsed with MIBC. A resist pattern having a 40 nm line / 80 nm line and space pattern was formed by spin-drying at 2,000 rpm for 15 seconds. The formed resist pattern is observed with a scanning electron microscope (manufactured by Hitachi High-Technologies), and the resist pattern formability is good when the bottom shape of the resist pattern does not become a flared shape in a 40 nm line and space pattern (A ) And the case where the skirt spreads out is judged as poor (B) in resist pattern formability. Pattern transfer was performed by sequentially dry-etching the inorganic film and the substrate to be processed using the formed resist pattern as a mask using a dry etching apparatus (Telius SCCM, manufactured by Tokyo Electron).

[Resist pattern formability, nanoimprint lithography]
A resist underlayer film forming composition (NFC HM8005, manufactured by JSR) is applied onto a silicon wafer as a substrate to be processed by a spin coater, and dried on a hot plate at 250 ° C. for 60 seconds to thereby form a resist underlayer having a film thickness of 300 nm. A film was formed. Each inorganic film forming composition was applied onto the formed resist underlayer film by a spin coater and baked on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a thickness of 20 nm. About 50 μL of the UV curable composition was spotted on the center of the experimental substrate on the formed inorganic film and placed on the work stage of a simple imprint apparatus (EUN-4200, manufactured by Engineering System). On the other hand, a quartz template (NIM-PH350, manufactured by NTT-ATN) coated with a release agent (trade name “HD-1100Z”, manufactured by Daikin Kasei Co., Ltd.) in advance by a predetermined method is used as a silicone rubber (thickness 0.2 mm). ) As an adhesive layer and attached to a quartz exposure head of a simple imprint apparatus. Next, after setting the pressure of the simple imprint apparatus to 0.2 MPa, the exposure head is lowered, the template and the experimental substrate are brought into close contact with each other via the photocurable composition for nanoimprint, and then UV exposure is performed for 15 seconds. did. After 15 seconds, the exposure stage was raised, and the template was peeled off from the cured shape transfer layer to form a pattern. The formed resist pattern is observed with a scanning electron microscope (manufactured by Hitachi High-Technologies). In a 50 nm line-and-space pattern, the resist pattern is not chipped and has a good resist pattern formability (A) It was determined that the resist pattern formability was poor (B) when there was pattern loss.

[Etching resistance]
The inorganic film was etched by two methods using the etching apparatus. First, the resist underlayer film (NFC HM8005) was etched under the condition of etching by 200 nm per minute. Second, the silicon dioxide film was etched under the condition of etching by 100 nm per minute. In any etching, when the difference between the initial film thickness and the film thickness after etching was less than 5 nm, the etching selectivity was judged as good (A), and when the difference was 5 nm or more, it was judged as bad (B). When it is determined that the etching selectivity is good, each of the inorganic film forming compositions functions well as a mask film when processing each film.

  As is apparent from the results shown in Table 2, the inorganic film-forming composition has an excellent etching selectivity, and when the inorganic film-forming composition is used, the formed resist pattern has excellent resist pattern formability. I understood.

  INDUSTRIAL APPLICABILITY The present invention can provide an inorganic film forming composition for a multilayer resist process and a pattern forming method that are excellent in resist pattern formability and etching selectivity. Therefore, in the multilayer resist process using the composition, even when the organic film is thinned, disappearance of the resist pattern, deformation of the shape, bending, and the like can be suppressed, and faithful pattern transfer is possible. Therefore, the present invention can be used very suitably for the manufacture of LSI, which is expected to be further miniaturized in the future, particularly for the formation of fine contact holes and the like.

Claims (7)

[A] At least one compound selected from the group consisting of a metal compound having a hydrolyzable group, a hydrolyzate of a metal compound having a hydrolyzable group, and a hydrolysis condensate of a metal compound having a hydrolyzable group ,
[B] an organic solvent, and [D] an inorganic film forming composition for a multilayer resist process containing a crosslinking accelerator,
[A] The compound contains at least one metal element selected from the group consisting of Group 6 elements, Group 12 elements and Group 13 elements, and the Group 6 element, Group 12 element and Group The content ratio of at least one metal element selected from the group consisting of group 13 elements is 70 mol% or more based on the total amount of metal elements and metalloid elements contained in the compound [A]. Inorganic film forming composition for multilayer resist process.   [C] The inorganic film forming composition for a multilayer resist process according to claim 1, further comprising water. (1) A step of forming an inorganic film on the upper side of the substrate to be processed using the inorganic film forming composition according to claim 1 or 2;
(2) a step of forming a resist film on the inorganic film using a resist composition;
(3) a step of exposing the resist film by irradiation with radiation through a photomask;
(4) a step of forming a resist pattern by developing the exposed resist film, and (5) a step of forming a pattern on the substrate to be processed by one or more dry etchings using the resist pattern as a mask. A pattern forming method. (0) forming a resist underlayer film on the substrate to be processed;
Further comprising
The pattern formation method according to claim 3, wherein an inorganic film is formed on the resist underlayer film in the step (1). The resist composition in the step (2) is
[Α] containing a polymer having an acid dissociable group that dissociates by the action of an acid,
The pattern forming method according to claim 3 or 4, wherein the development in the step (4) is performed with an organic solvent developer to form a negative resist pattern. (1) A step of forming an inorganic film on the upper side of the substrate to be processed using the inorganic film forming composition according to claim 1 or 2;
(2 ′) a step of forming a resist pattern on the inorganic film by nanoimprint lithography, and (5) a step of forming a pattern on a substrate to be processed by one or more dry etching using the resist pattern as a mask. A pattern forming method. (0) forming a resist underlayer film on the substrate to be processed;
Further comprising
The pattern forming method according to claim 6, wherein an inorganic film is formed on the resist underlayer film in the step (1).