Composition for forming inorganic film for multilayer resist process, and method for forming pattern

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

With the miniaturization of semiconductor devices and the like, the processing size using a multilayer resist process is being miniaturized in order to obtain a higher degree of integration. In this multilayer resist process, an inorganic film is formed using a silicon-based inorganic material, and then a resist composition is further applied to form a resist film which is an organic film having an etching selectivity different from that of the inorganic film, and then by exposure. A resist pattern is obtained by transferring the mask pattern and developing it with a developing solution. 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 to obtain a substrate having a desired pattern (Japanese Patent Laid-Open No. 2001). -Refer to JP-A-284209, JP-A-2010-85912 and JP-A-2008-39811).

On the other hand, in order to process the substrate to be processed more finely, it is necessary to thin the resist film. However, when the resist film is thinned by using a conventional inorganic material such as a silicon oxide film, there is a disadvantage that the resist pattern disappears, loses its shape, bends, and the like, making it difficult to transfer the desired pattern.

<p><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2001-284209</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2010-85912</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2008-39811</text></patcit></p>

<p> The present invention has been made based on the above circumstances, and an object of the present invention is excellent in formability and etching selectivity of a resist pattern formed on an inorganic film, and is faithful even when the resist film is thinned. It is an object of the present invention to provide an inorganic film forming composition for a multilayer resist process capable of pattern transfer, and a pattern forming method.</p>

<p> 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 hydrolyzate condensate of a metal compound having a hydrolyzable group. , [B] Organic solvent, as well [D] Crosslink accelerator An inorganic film-forming composition for a multilayer resist process containing The compound [A] contains at least one metal element (hereinafter, also referred to as "specific element") selected from the group consisting of Group 6 elements, Group 12 elements and Group 13 elements, and the above-mentioned first compound. The content ratio of at least one metal element selected from the group consisting of Group 6 elements, Group 12 elements and Group 13 elements is 50 with respect to the total amount of metal elements and semi-metal elements contained in the [A] compound. It is an inorganic film forming composition for a multilayer resist process, characterized in that it is in mol% or more.</p><p> The composition contains the [A] compound, and the content ratio of the specific element is within the above specific range, and the [D] cross-linking accelerator is contained, so that the [A] compound is treated by heating or the like. As a result, the etching selectivity between the formed inorganic film and the organic film can be improved.</p><p> The composition preferably further contains [C] water. The composition can promote the inorganic film forming reaction by further containing [C] water.</p><p> The pattern forming method of the present invention (hereinafter, also referred to as "pattern forming method (I)") is (1) A process 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 the resist composition. (3) A step of exposing the resist film by irradiating 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 a substrate to be processed by one or a plurality of dry etchings using the resist pattern as a mask. Have.</p><p> According to the pattern forming method (I), even when the resist film is thinned, the resist pattern can be suppressed from disappearing, losing its shape, bending, etc., and faithful pattern transfer becomes possible. As a result, the present invention can be suitably applied to pattern formation in which a finer processing size is required.</p><p> The pattern forming method is (0) A process of forming a resist underlayer film on a substrate to be processed, Have more In the step (1), it is also preferable to form an inorganic film on the resist underlayer film.</p><p> Since an excellent etching selectivity can be obtained between the organic material and the inorganic material in the composition, the resist pattern transfer is good by sequentially using the dry etching process on the inorganic film and the resist underlayer film having the organic film. Can be done.</p><p> The resist composition in the above step (2) is A polymer having an acid dissociative group that dissociates due to the action of [α] acid (hereinafter, also referred to as [α] polymer). Contains, It is preferable that the development in the above step (4) is carried out with an organic solvent developer to form a negative resist pattern.</p><p> As described above, with the above configuration, it is possible to suppress the film loss of the resist pattern. As a result, according to the pattern forming method, more faithful pattern transfer becomes possible.</p><p> Another pattern forming method of the present invention (hereinafter, also referred to as "pattern forming method (II)") is (1) A process of forming an inorganic film on the upper side of the substrate to be processed using the composition. (2') The step of forming a resist pattern on the inorganic film by the nanoimprint lithography method, and (5) A step of forming a pattern on a substrate to be processed by one or a plurality of dry etchings using the resist pattern as a mask. Have.</p><p> In addition, the pattern formation method (II) is (0) A process of forming a resist underlayer film on a substrate to be processed, Have more In the step (1), it is also preferable to form an inorganic film on the resist underlayer film.</p><p> According to the pattern forming method (II), faithful pattern transfer is possible through the formation of a resist pattern by the nanoimprint lithography method.</p>

<p> The present invention can provide an inorganic film forming composition for a multilayer resist process, which is excellent in resist pattern forming property and etching selectivity, and a pattern forming method. Therefore, in the multilayer resist process using the composition, even when the organic film is thinned, the resist pattern disappears, loses its shape, bends, and the like can be suppressed, and faithful pattern transfer becomes possible. Therefore, the present invention can be extremely suitably used for manufacturing LSIs, which are expected to be further miniaturized in the future, particularly for forming fine contact holes and the like.</p>

&lt;Inorganic film forming composition for multilayer resist process&gt; The inorganic film-forming composition for a multilayer resist process of the present invention contains [A] compound, [B] organic solvent and [D] cross-linking accelerator. In addition, [C] water can be contained as a suitable component. Furthermore, the composition may contain other optional components as long as the effects of the present invention are not impaired. The composition can form an inorganic film having excellent formability of a resist pattern formed on the inorganic film and resistance to dry etching, and can be suitably used for a multilayer resist process. Hereinafter, each component will be described in detail.

&lt;[A] Compound&gt; 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 hydrolyzed condensate of a metal compound having a hydrolyzable group. It is a compound of the species. The [A] 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 Group 6 elements, Group 12 elements and Group 13 elements is the total amount of metal elements and semi-metal elements contained in the [A] compound. On the other hand, it is 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% or more.

As a specific element, for example Group 6 elements such as Cr (chromium), Mo (molybdenum), W (tungsten); Group 12 elements such as Zn; Group 13 elements such as Al (aluminum), Ga (gallium), In (indium), and Tl (thallium) can be mentioned.

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

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

<chemistry num="1"><img file="JP2012215877A_D0001.tif" /></chemistry>

In the above formula (1), M is an atom of a specific element. a is an integer from 1 to 7 corresponding to the valence of the atom M. R¹Is 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, R¹If there are multiple Rs¹May be the same or different.

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

<chemistry num="2"><img file="JP2012215877A_D0002.tif" /></chemistry>

In the above equation (2), R²Is R in the above equation (1)¹Is synonymous with.

R above²Examples of the compound represented by the above formula (2) when is an alkyl group or a cycloalkyl group include methanol, ethanol, 1-propanol, 2-propanol, n-butanol, sec-butanol, pentanol and cyclohexanol. And so on. R above²Examples of the compound represented by the above formula (2) in the case where is an alkyl group or a cycloalkyl group substituted with an alkoxy group include methoxymethanol, methoxyethanol, ethoxymethanol, ethoxyethanol, methoxypropanol, ethoxypropanol and propoxy. Examples include propanol.

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

<chemistry num="3"><img file="JP2012215877A_D0003.tif" /></chemistry>

In the above equation (3), M and a are synonymous with the above equation (1). R³Is an organic group. However, R³If there are multiple Rs³May be the same or different.

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

<chemistry num="4"><img file="JP2012215877A_D0004.tif" /></chemistry>

In the above formula (4), R⁴Is R in the above equation (3)³Is synonymous with.

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 thereof 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).

<chemistry num="5"><img file="JP2012215877A_D0005.tif" /></chemistry>

In the above equation (5), M and R¹Is synonymous with the above equation (1). R³Is synonymous with the above equation (3). b and c are independently integers from 0 to 7. However, b + c corresponds to the valence of the atom M. d is an integer from 0 to 7. R⁵Is an organic compound. However, R⁵If there are multiple Rs⁵May be the same or different.

R above⁵Examples of the organic compound represented by (6) include ethers represented by the following formula (6).

<chemistry num="6"><img file="JP2012215877A_D0006.tif" /></chemistry>

In the above formula (6), R⁶And R⁷Is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms which may have an oxygen atom in the skeletal chain. However, R⁶And R⁷May be coupled to each other to form a ring structure.

Examples of 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.

R above⁵Examples of the organic compound represented by the above include ketones represented by the following formula (7) or formula (8).

<chemistry num="7"><img file="JP2012215877A_D0007.tif" /></chemistry>

In the above equations (7) and (8), R⁸And R¹⁰Are saturated or unsaturated hydrocarbon groups having 1 to 10 carbon atoms, each of which may independently have a keto group in the skeletal chain. R⁹And R¹¹Are independently saturated or unsaturated hydrocarbon groups 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, and trimethyl nonanone. Acetonylacetone, mesityloxide, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), acetylacetone (2,4-pentandione), 2,4-trifluoropentandione, 2,4- Hexafluoropentandione, ethylacetacetate, 2,2,6,6-tetramethyl-3,5-heptandione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butandione, etc. Can be mentioned.

R above⁵Examples of the organic compound represented by (9) include esters represented by the following formula (9).

<chemistry num="8"><img file="JP2012215877A_D0008.tif" /></chemistry>

In the above equation (9), R¹⁴Is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms which may have a keto group, a hydroxy group or an alkoxy group. R¹⁵Is 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, and methoxybutyl. Examples thereof include acetate, diethyl oxalate and diethyl malonate.

The hydrolyzate is obtained by hydrolyzing the [A] compound. The hydrolyzed 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 hydrolyzed condensate is 50 mol% or more, preferably 70 mol% or more, based on the total amount of the metal element and the metalloid element contained in the hydrolyzed condensate. More preferably, it is 90 mol% or more. Hydrolysis is carried out 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. The amount of water used is usually 100 mol or less, preferably 5 mol to 50 mol, with respect to 100 mol of the [A] compound. Examples of the catalyst include inorganic acids such as hydrochloric acid, sulfuric acid and nitrate; acid catalysts such as organic acids such as acetic acid, propionic acid, butyric acid and maleic acid, sodium hydroxide, potassium hydroxide, ammonia, monoethanolamine and diethanolamine. Examples thereof include inorganic or organic alkaline catalysts such as tetramethylammonium hydroxide.

&lt;[B] Organic solvent&gt; In the present invention, the composition is obtained by dissolving or dispersing the [A] compound and the [D] cross-linking accelerator in the [B] organic solvent. [B] Examples of the organic solvent include alcohol-based solvents, ketone-based solvents, amide-based solvents, ether-based solvents, ester-based solvents, and mixed solvents thereof. These solvents may be used alone or in combination of two or more.

As an alcohol solvent, for example 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-heptadecyl alcohol, flufuryl alcohol, phenol, cyclohexanol, methylcyclo Monoalcohol-based solvents such as hexanol, 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-heptandiol, 2 -Polyhydric alcohol-based solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and 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 solvent such as dipropylene glycol monopropyl ether and the like.

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 thereof include ketone solvents such as butyl ketone, trimethylnonanonone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentandione, acetonylacetone, diacetone alcohol, and acetophenone.

Examples of the amide solvent include N, N'-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and the like. Examples thereof include N-methylpropionamide and N-methylpyrrolidone.

Examples of the ester solvent 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 and acetic acid. n-pentyl, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, acetoacetate Ethyl, 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 acetate Monopropyl ether, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, Examples thereof include diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

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

As for the content of the [B] 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. The amount is preferred.

&lt;[D] Crosslink accelerator&gt; [D] The cross-linking accelerator is a compound that generates an acid or a base by light or heat. When the composition contains the [D] cross-linking accelerator, the etching selectivity between the inorganic film and the organic film is improved. [D] Examples of the cross-linking accelerator include onium salt compounds and N-sulfonyloxyimide compounds. [D] As the cross-linking accelerator, a thermal cross-linking accelerator that generates an acid or a base by heat is preferable, and an onium salt compound is particularly preferable.

Examples of the onium salt compound include a sulfonium salt, a tetrahydrothiophenium salt, an iodonium salt, an ammonium salt and the like.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, and triphenylsulfonium 2-bicyclo [2.2.1] hept-2-. Il-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n- Octane Sulfonium, 4-Cyclohexylphenyl Diphenyl Sulfonium 2-Bicyclo [2.2.1] Hept-2-yl-1,1,2,2-Tetrafluoroethane Sulfonium, 4-Methanesulfonylphenyldiphenyl Sulfonium Trifluoromethane Sulfonium, 4-Methane Sulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1, Examples thereof include 1,2,2-tetrafluoroethanesulfonate and triphenylphosphonium 1,1,2,2-tetrafluoro-6- (1-adamantan carbonyloxy) -hexane-1-sulfonate.

Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium trifluoromethanesulfonate and 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium nona. Fluoro-n-butane sulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium Perfluoro-n-octane sulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Nium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (6-n-Butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butane sulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octane Sulfonate, 1- (6-n-butoxynaphthalen-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-butane sulfonate, 1- (3,, 5-Dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2 -Il-1,1,2,2-tetrafluoroethanesulfonate and the like can be mentioned.

Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butane sulfonate, diphenyliodonium perfluoro-n-octane sulfonate, and diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1, 1,2,2-Tetrafluoroethane sulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butane sulfonate, bis (4-t-butyl) Phenyl) iodonium perfluoro-n-octane sulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, etc. Be done.

Examples of the ammonium salt include ammonium formate, ammonium maleate, ammonium fumarate, ammonium phthalate, ammonium malate, ammonium succinate, ammonium tartrate, ammonium malate, ammonium lactate, ammonium citrate, ammonium acetate, ammonium propionate, etc. Ammonium butanoate, ammonium pentanate, ammonium hexanoate, ammonium heptate, ammonium octanate, ammonium nonanoate, ammonium decanoate, ammonium oxalate, ammonium adipate, ammonium sebacate, ammonium butyrate, ammonium oleate, ammonium stearate , Ammonium linoleate, ammonium linoleate, ammonium salicylate, ammonium benzenesulfonate, ammonium benzoate, ammonium p-aminobenzoate, ammonium p-toluenesulfonate, ammonium methanesulfonate, ammonium trifluoromethanesulfonate, trifluoroethanesulfone Examples include ammonium acid. 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. Ions, tripropylammonium ions, tetrapropylammonium ions, butylammonium ions, dibutylammonium ions, tributylammonium ions, tetrabutylammonium ions, trimethylethylammonium ions, dimethyldiethylammonium ions, dimethylethylpropylammonium ions, methylethylpropylbutylammonium ions Ammonium salts substituted with ions, ethanolammonium ions, diethanolammonium ions, triethanolammonium ions, etc. are listed. You can get rid of it. Further, 1,8-diazabicyclo [5.4.0] undeca-7-ene salt, 1,5-diazabicyclo [4.3.0] -5-nonene salt and the like can be mentioned. 1,8-diazabicyclo [5.4.0] undeca-7-ene salt is 1,8-diazabicyclo [5.4.0] undeca-7-enelate, 1,8-diazabicyclo [5.4.0] undeca-7- Enp-toluenesulfonic acid and the like can be mentioned.

Examples of the N-sulfonyloxyimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxyimide and N- (nonafluoro-n-butanesulfonyloxy) bicyclo. [2.2.1] Hept-5-ene-2,3-dicarboxyimide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] Hept-5-en-2,3-dicarboxyimide , N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxy Examples include imide.

Among these [D] cross-linking accelerators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalene-1-yl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalene-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, 1,8-diazabicyclo [5.4.0] undeca- 7-En salt is preferred.

These [D] cross-linking accelerators may be used alone or in combination of two or more. The amount of the [D] cross-linking accelerator used is preferably 10 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the [A] compound. [D] By setting the amount of the cross-linking accelerator to be used within the above-mentioned specific range, the etching selectivity can be improved.

&lt;[C] Water&gt; The composition preferably further contains [C] water as a suitable component. The composition can promote the inorganic film forming reaction by further containing [C] water. [C] Water is not particularly limited, and examples thereof include distilled water and ion-exchanged 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.

&lt;Other optional ingredients&gt; The inorganic film-forming composition may contain other optional components such as a surfactant as long as the effects of the present invention are not impaired.

[Surfactant] Surfactants are components that have the 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, and polyethylene glycol di. In addition to nonionic surfactants such as stearate, the following product names are KP341 (manufactured by Shinetsu Chemical Industry Co., Ltd.), Polyflow No.75, No.95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, and the same. EF352 (above, made by Tochem Products), Megafuck F171, F173 (above, manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surfron S-382, same Examples thereof include SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (all manufactured by Asahi Glass).

The surfactant may be used alone or in combination of two or more. In addition, the blending amount of the surfactant can be appropriately determined according to the purpose.

&lt;Method of preparing inorganic film forming composition for multilayer resist process&gt; The composition can be prepared, for example, by mixing [A] compound, [C] water, [D] cross-linking accelerator, and other optional components in a predetermined ratio in a [B] organic solvent. The composition is usually prepared by dissolving it in a solvent at the time of its use and then filtering it with a filter having a pore size of about 0.2 μm, for example.

&lt;Pattern formation method (I)&gt; The pattern forming method (I) of the present invention is (1) A process 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 the resist composition. (3) A step of exposing the resist film by irradiating 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 a substrate to be processed by one or a plurality of dry etchings using the resist pattern as a mask. Have.

According to the pattern forming method (I), even when the resist film is thinned, the resist pattern can be suppressed from disappearing, losing its shape, bending, etc., and faithful pattern transfer becomes possible. As a result, the present invention can be suitably applied to pattern formation in which a finer processing size is required.

In addition, the pattern formation method is (0) A process of forming a resist underlayer film on a substrate to be processed, Have more In the step (1), it is preferable to form an inorganic film on the resist underlayer film.

The resist composition in the above step (2) is Polymer with acid dissociative group dissociated by the action of [α] acid Contains, It is preferable that the development in the above step (4) is carried out with an organic solvent developer to form a negative resist pattern.

Since an excellent etching selectivity can be obtained between the organic material and the inorganic material in the composition, the transfer of the resist pattern is good by sequentially using the dry etching process on the inorganic film and the resist underlayer film which is an organic film. Can be done. Hereinafter, each step will be described in detail.

[Process (1)] In this step, the composition is used to form an inorganic film on the upper side of the substrate to be processed. Examples of the substrate to be processed include insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, as well as commercially available black diamonds (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 the low dielectric insulating film of the above can be mentioned. Further, as the substrate to be processed, a patterned substrate such as a wiring circuit (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 applying it to 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. It can be formed by making it. Examples of the method for applying the composition include a spin coating method, a roll coating method, a dip method and the like. The heating temperature is usually 150 ° C to 500 ° C, preferably 180 ° C to 350 ° C. The heating time is usually 30 seconds to 1,200 seconds, preferably 45 seconds to 600 seconds. Further, ultraviolet light irradiation may be performed after the composition is applied. The film thickness of the inorganic film is usually about 5 nm to 50 nm.

[Process (0)] Further, before the step (1), there may be a step of forming a resist underlayer film on the substrate to be processed. Examples of the resist underlayer film include an organic film formed by using a composition for a resist underlayer film, a carbon film formed by a conventionally known CVD (Chemical Vapor Deposition) method, and the like. As the resist underlayer film forming composition, conventionally known ones 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 applying it on a substrate to be processed, and this coating film is heat-treated, or irradiated with ultraviolet light and heat-treated. It can be formed by curing with. Examples of the method for applying the resist underlayer film forming composition include a spin coating method, a roll coating method, and a dip method. The heating temperature is usually 150 ° C to 500 ° C, preferably 180 ° C to 350 ° C. The heating time is usually 30 seconds to 1,200 seconds, preferably 45 seconds to 600 seconds. The film thickness of the resist underlayer film is usually about 50 nm to 500 nm.

Further, on the surface of the substrate to be processed, another underlayer film different from the resist underlayer film obtained by using the resist underlayer film forming composition may be formed. Other underlayers have antireflection function, coating film flatness, and CF.₄It is a film imparted with high etching resistance to fluorine-based gas such as. As the other underlayer film, for example, a commercially available product such as NFC HM8005 (manufactured by JSR) can be used.

[Process (2) ~ (4)] In steps (2) to (4), the resist composition is applied onto the inorganic film and exposed, heated and developed to form a resist pattern. The resist composition is a chemically amplified resist composition containing, for example, an acid generator, and the exposed portion exhibits solubility in an alkaline water-soluble developer and poor solubility in an organic solvent developer. The exposed part consists of an alkali-water-soluble developer, a chemically amplified resist composition that is sparingly soluble in an organic solvent developer, an alkali-soluble resin, and a quinonediazide-based photosensitizer. However, examples thereof include a resist composition showing solubility in an alkaline water-soluble developer. 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 sparingly soluble in an organic solvent developer. Is preferable.

The resist coating film is formed by prebaking the coating film formed by applying the resist composition to volatilize the solvent in the coating film (that is, the solvent contained in the resist composition). Can be done. The prebake temperature is appropriately adjusted according to the type of resist composition used and the like, 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, another coating film may be further provided 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 obtained 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 rays, far ultraviolet rays, X-rays, electron beams, γ-rays, molecular rays, ion beams, etc., depending on the type of acid generator used in the resist composition. However, it is preferably far ultraviolet light, and KrF excimer laser (248 nm), ArF excimer laser (193 nm), F.₂Excimer laser (wavelength 157 nm), Kr₂Excimer lasers (wavelength 147 nm), ArKr excimer lasers (wavelength 134 nm), and extreme ultraviolet rays (wavelength 13.5 nm, etc.) are more preferable. Moreover, the immersion exposure method can also be adopted. An immersion upper layer film may be formed on the resist film by using the immersion upper layer film forming composition.

Post-exposure baking (PEB) is performed after exposure to improve the resolution, pattern profile, developability, etc. of the resist film. The temperature of this PEB is appropriately adjusted according to the type of resist composition used and the like, but is preferably 180 ° C. or lower, 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, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n-propylamine and the like. Secondary amines, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, quaternary such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine and choline. Cyclic amines such as ammonium salts, pyrrole and piperidine, and alkaline aqueous solutions such as 1,8-diazabicyclo [5.4.0] -7-undecene and 1,5-diazabicyclo [4.3.0] -5-nonen can be mentioned. Further, these alkaline aqueous solutions may be those to which an appropriate amount of a water-soluble organic solvent, for example, alcohols such as methanol or ethanol, or a surfactant is added.

Examples of the organic solvent developing solution include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents, and the like.

Examples of the alcohol solvent include, for example. Monoalcoholic 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, and dipropylene glycol monoethyl ether. Examples include system solvents and the like.

Examples of the ether solvent include, for example. Dialiphatic ethers such as dipropyl ether and dibutyl ether; diaromatic ethers such as diphenyl ether and ditril ether; Aromatic-aliphatic ethers such as anisole and phenylethyl ether can be mentioned.

Examples of the ketone solvent include, for example. 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 An aliphatic ketone solvent such as nonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentandione, acetonylacetone, acetophenone; Aliphatic-aromatic ketone solvents such as acetophenone, propiophenone, trillmethylketone; Examples thereof include aromatic ketone solvents such as benzophenone, trilphenylketon, and ditrilketone.

Examples of the amide solvent include, 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 can be mentioned.

Examples of the ester solvent include, 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, methylpentyl acetate , 2-ethyl butyl acetate, 2-ethyl hexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl aceto acetate, ethyl aceto acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, propion Monoester solvents such as acid iso-amyl, 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, 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-based 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, for example. aliphatic hydrocarbons such as n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, methylcyclohexane, etc. Hydrocarbon solvent; Fragrances of benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene, etc. Examples thereof include group hydrocarbon-based solvents.

Among these, ether-based solvents, ketone-based solvents, and ester-based solvents are preferable. As the ether solvent, an aromatic-aliphatic ether solvent is more preferable, and anisole is further preferable. As the ketone solvent, an aliphatic ketone solvent is more preferable, and methyl amyl ketone is further preferable. As the ester solvent, a monoester solvent is more preferable, and butyl acetate is further preferable. These organic solvents may be used alone or in combination of two or more.

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 developing solution to 80% by mass or more, the contrast of the pattern depending on the presence or absence of exposure can be improved, and as a result, a pattern having excellent development characteristics and lithography characteristics can be formed. it can. 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. After development, it is preferable to wash the resist pattern with a rinsing solution.

[Process (5)] In this step, a pattern is formed on the substrate to be processed by one or a plurality of dry etchings 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 the pattern. Dry etching can be performed using a known dry etching apparatus. The source gas for dry etching depends on the elemental composition of the object to be etched, but O₂, CO, CO₂Gas containing oxygen atoms such as He, N₂, Ar and other inert gases, Cl₂, BCl₃Chlorine gas, CHF, etc.₃, CF₄Fluorine gas, H, etc.₂, NH₃Gas etc. can be used. In addition, these gases can also be mixed and used.

The resist composition in the above step (2) is Polymers with acid dissociative groups that dissociate by the action of [α] acid and [β] Acid generator Contains, It is preferable that the development in the above step (4) is carried out with an organic solvent developer to form a negative resist pattern. Further, the resist composition may contain a polymer other than the [α] polymer.

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

<chemistry num="9"><img file="JP2012215877A_D0009.tif" /></chemistry>

In the above equation (10), R^pIs an acid dissociative group.

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

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

<chemistry num="10"><img file="JP2012215877A_D0010.tif" /></chemistry>

In the above equation (11), R¹⁶Is a hydrogen atom, a methyl group or a trifluoromethyl group. R^pIs synonymous with the above equation (10).

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

R above^pThe acid dissociative group represented by is preferably represented by the following formula (12).

<chemistry num="11"><img file="JP2012215877A_D0011.tif" /></chemistry>

In the above equation (12), R^p1~ R^p3Is an alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group having 4 to 20 carbon atoms. However, some or all of the hydrogen atoms of the above alkyl group and alicyclic hydrocarbon group may be substituted. Also, R^p2And R^p3May 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 each is bonded.

R in the above equations (10) and (11)^pBy using the acid dissociative group represented by the above formula (12) as a group having a specific structure represented by the above formula (12), the acid dissociative group can be easily dissociated by the action of an acid generated in the exposed portion. 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 the film loss can be further suppressed.

[[β] Acid generator] The [β] acid generator generates an acid upon exposure, and the acid causes the acid present in the [α] polymer. The solubility of the [α] polymer in a developing solution is changed by dissociating a dissociative group or the like.

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

Examples of the onium salt compound include a sulfonium salt and a tetrahydrothiophenium salt. , Iodonium salt, phosphonium salt, diazonium salt, pyridinium salt and the like.

Of these, onium salt compounds are preferred, sulfonium salts are more preferred, triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate, triphenylsulfonium 2- (1-adamantyl). -1,1-difluoroethane sulfonate is more preferred. As the [β] acid generator, one kind or two or more kinds may be used.

When the [β] acid generator is an acid generator, the content is usually 0.1 mass by mass with respect to 100 parts by mass of the [α] polymer from the viewpoint of ensuring the sensitivity and developability of the resist composition. 2 parts or more and 20 parts by mass or less, preferably 0.5 parts by mass or more and 15 parts by mass or less.

When the development in the above step (4) is carried out with an organic solvent developing solution to form a negative type resist pattern, the organic solvent is selected from the group consisting of an ether solvent, a ketone solvent and an ester solvent. It is preferably at least one organic solvent. As a result, the solubility of the exposed portion in the developing solution can be further reduced, and the film loss can be further suppressed.

&lt;Pattern formation method (II)&gt; The pattern forming method (II) of the present invention is (1) A process of forming an inorganic film on the upper side of the substrate to be processed using the composition. (2') The step of forming a resist pattern on the inorganic film by the nanoimprint lithography method, and (5) A step of forming a pattern on a substrate to be processed by one or a plurality of dry etchings using the resist pattern as a mask. Have.

In addition, the pattern formation method (II) is (0) A process of forming a resist underlayer film on a substrate to be processed, Have more In the step (1), it is preferable to form an inorganic film on the resist underlayer film.

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

[Process (2')] The step (2') is a step of forming a resist pattern on the inorganic film by the nanoimprint lithography method. This resist pattern can be formed using, for example, a radiation-sensitive curable composition. Specifically, in step (1), a pattern forming layer is formed by applying a radiation-sensitive curable composition on a substrate on which an inorganic film is formed, and the surface of a mold having an inverted pattern on the surface is hydrophobic. A step of pressure-welding the surface of the hydrophobized mold to the pattern-forming layer, a step of exposing the pattern-forming layer with the mold pressed, and a step of exposing the mold to the exposed pattern-forming layer. It is a method including a step of peeling from.

In this case, the curable composition may contain a curing accelerator or the like. 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. Two or more types of radiation-sensitive curing accelerators may be used in combination.

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

In the hydrophobizing treatment step of the mold, the surface of the mold having an inversion pattern on the surface is hydrophobized with a mold release agent or the like. The mold needs to be made of a light transmissive material. Examples of the light-transmitting material include a phototransparent resin such as glass, quartz, PMMA, and polycarbonate resin; a transparent metal vapor deposition film; a flexible film such as polydimethylsiloxane; a photocurable film; and a metal film.

Examples of the release agent include a silicon-based release agent, a fluorine-based release agent, a polyethylene-based release agent, a polypropylene-based release agent, a paraffin-based release agent, a Montan-based release agent, a carnauba-based release agent, and the like. Can be mentioned. The release agent may be used alone or in combination of two or more. Of these, a silicon-based release agent is preferable. Examples of the silicon-based release agent include polydimethylsiloxane, acrylic silicone graft polymer, acrylicsiloxane, and arylsiloxane.

The pressure welding step is a step of pressing the hydrophobized mold onto the pattern forming layer. By pressing a mold having an uneven pattern on the pattern forming layer, a mold uneven pattern is formed in the pattern forming layer. The pressure at the time of pressure welding 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 pressure contact 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 pressure-welded. By exposing the pattern-forming layer, radicals are generated from the photopolymerization initiator contained in the radiation-sensitive composition for nanoimprint. As a result, the pattern forming layer made of the radiation-sensitive composition for nanoimprint is cured in a state where the uneven pattern of the mold is transferred. By transferring the uneven pattern, it can be used, for example, as an interlayer insulating film for semiconductor elements such as LSI, system LSI, DRAM, SDRAM, RDRAM, and D-RDRAM, and as a resist film for manufacturing semiconductor elements.

When the curable composition is thermosetting, it is cured by a heat curing step instead of the above exposure step. When thermosetting is performed, the heating atmosphere, heating temperature, and the like are not particularly limited, but for example, it can be heated at 40 ° C to 200 ° C in an inert atmosphere or under reduced pressure. Heating can be performed using a hot plate, an 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 for peeling, or the mold may be fixed and the base material may be moved away from the mold for peeling. Alternatively, both of them may be pulled in opposite directions to peel off.

<p> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.</p><p>&lt;[A] Compound&gt; The [A] compounds used in Synthesis Examples, Examples and Comparative Examples are as follows. A-1: Tungsten (V) ethoxide A-2: Bis (2,4-pentanionate) zinc A-3: Aluminum (III) 2,4-pentanionate A-4: Indium (III) 2,4-pentanegeonate A-5: Tetramethoxysilane A-6: Tilt remethoxysilane A-7: Phenyltrimethoxysilane</p><p>[Synthesis example 1] Mix 30.00 g of the above (A-1) and 60.00 g of propylene glycol monomethyl ether (PGME), stir at 25 ° C for 10 minutes, mix 10.00 g of water, raise the temperature to 60 ° C, and heat for 4 hours. Stirring was performed. After completion of the reaction, the mixture was cooled to room temperature, 30.00 g of propylene glycol monomethyl ether was added, and the low boiling point was removed with an evaporator to obtain a solution of the hydrolyzed condensate (A-8). The solid content concentration of the solution of (A-8) was 10.98% as a result of measurement by the firing method.</p><p>[Synthesis example 2 ~ 5] Hydrolyzed condensates (A-9) to (A-12) were synthesized in the same manner as in Synthesis Example 1 except that the types and amounts shown in Table 1 were used.</p><p>[Synthesis example 6] An aqueous solution of oxalic acid was prepared by heating and dissolving 0.40 g of oxalic acid in 19.20 g of water. Set the cooling tube and the dropping funnel containing the prepared oxalic acid aqueous solution in the flask containing 9.46 g of (A-5), 3.02 g of (A-6), 0.88 g of (A-7) and 67.04 g of PGME. did. Then, after heating to 60 ° C. in an oil bath, an aqueous oxalic acid solution was slowly added dropwise, and the mixture was reacted at 60 ° C. 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 the low boiling point substance was removed by the evaporator to obtain a solution of the hydrolyzed condensate (A-13). The solid content concentration of the solution of (A-13) was 11.90% as a result of measurement by the firing method. The weight average molecular weight (Mw) of the solid content was 2,900.</p><p><tables num="1"><img file="JP2012215877A_D0012.tif" /></tables></p><p>&lt;Preparation of Inorganic Film Forming Composition for Multilayer Resist Process&gt; The [B] organic solvent and [D] cross-linking accelerator used in Examples and Comparative Examples are as follows.</p><p>&lt;[B] Organic solvent&gt; B-1: Propylene glycol monomethyl ether B-2: Propylene glycol monoethyl ether</p><p>&lt;[D] Crosslink accelerator&gt; D-1: Diphenyliodonium trifluoromethanesulfonate D-2: 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium trifluoromethanesulfonate D-3: Tetramethylammonium acetate D-4: 1,8-diazabicyclo [5.4.0] Undeca-7-en p-toluenesulfonate</p><p>[Example 1] After dissolving 17.34 parts by mass of (A-8) as a compound in 46.50 parts by mass of (B-1) and 31.06 parts by mass of (B-2) as an organic solvent, (C) 5.00 parts by mass. After adding 0.10 parts by mass of (D-2), this solution was filtered through a filter having a pore size of 0.2 μm to prepare an inorganic film-forming composition for a multilayer resist process.</p><p>[Examples 2 to 5 and Comparative Example 1] Each inorganic film-forming composition of the multilayer resist process was prepared by the same operation as in Example 1 except that each component of the type and amount shown in Table 2 was used. In addition, "-" indicates that the corresponding component was not used.</p><p>&lt;Evaluation&gt; 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 also shown in Table 2.</p><p>[Resist pattern forming property, alkaline aqueous solution development] A resist underlayer film forming composition (NFC HM8005, manufactured by JSR) is applied on 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 obtain a resist having a film thickness of 300 nm. An underlayer film was formed. Each inorganic film-forming composition was applied onto the formed resist underlayer film by a spin coater and fired on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a film thickness of 20 nm. A resist composition (ARX2014J, manufactured by JSR) was applied onto the formed inorganic film and dried at 90 ° C. for 60 seconds to form a resist film having a film thickness of 100 nm. An immersion upper layer film forming composition (NFC TCX091-7, manufactured by JSR) was applied onto the formed resist film and dried at 90 ° C. for 60 seconds to form an immersion upper layer film having a film thickness of 30 nm. After that, using an ArF excimer laser irradiation device (S610C, manufactured by Nikon), 16 mJ / cm by immersion method.²After the exposure treatment with the laser irradiation amount of, the substrate to be processed was heated at 115 ° C. for 60 seconds. Then, it was developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 30 seconds to form a resist pattern of a 50 nm line-and-space pattern in which the resist remaining on the silicon wafer and the width of the formed groove were 50 nm each. did. The formed resist pattern is observed with a scanning electron microscope (manufactured by Hitachi High-Tech), and when the bottom shape of the resist pattern does not become a hem-spreading shape in a 50 nm line-and-space pattern, the resist pattern formability is good (A). ), And the resist pattern formability was judged to be poor (B) when the hem was widened. Using the formed resist pattern as a mask, the pattern was transferred by sequentially dry-etching the inorganic film and the substrate to be processed using a dry etching apparatus (Telius SCCM, manufactured by Tokyo Electron Limited).</p><p>[Resist pattern forming property, organic solvent development] A resist underlayer film forming composition (NFC HM8005, manufactured by JSR) is applied on 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 obtain a resist having a film thickness of 300 nm. An underlayer film was formed. Each inorganic film-forming composition was applied onto the formed resist underlayer film by a spin coater and fired on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a film thickness of 20 nm. The resist composition was applied onto the formed inorganic film and dried at 90 ° C. for 60 seconds to form a resist film having a film thickness of 100 nm. An immersion upper layer film forming composition (NFC TCX091-7, manufactured by JSR) was applied onto the formed resist film and dried at 90 ° C. for 60 seconds to form an immersion upper layer film having a film thickness of 30 nm. After that, using an ArF excimer laser irradiation device (S610C, manufactured by Nikon), 16 mJ / cm by immersion method.²After the exposure treatment with the laser irradiation amount of, the substrate to be processed was heated at 115 ° C. for 60 seconds. Then, butyl acetate was used as a developer for paddle development (30 seconds) and rinsed with MIBC. A resist pattern with 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-Tech), and when the bottom shape of the resist pattern does not become a hem-spreading shape in a 40 nm line-and-space pattern, the resist pattern formability is good (A). ), And the resist pattern formability was judged to be poor (B) when the hem was widened. Using the formed resist pattern as a mask, the pattern was transferred by sequentially dry-etching the inorganic film and the substrate to be processed using a dry etching apparatus (Telius SCCM, manufactured by Tokyo Electron Limited).</p><p>[Resist pattern formability, nanoimprint lithography method] Resist underlayer film forming composition (NFC) on a silicon wafer as a substrate to be processed HM8005 (manufactured by JSR) was applied by a spin coater and dried on a hot plate at 250 ° C. for 60 seconds to form a resist underlayer film having a film thickness of 300 nm. Each inorganic film-forming composition was applied onto the formed resist underlayer film by a spin coater and fired on a hot plate at 250 ° C. for 60 seconds to form an inorganic film having a film thickness of 20 nm. Approximately 50 μL of the UV curable composition was spotted on the formed inorganic film in the center of the experimental substrate, and installed on the work stage of a simple imprint device (EUN-4200, manufactured by Engineering Systems Co., Ltd.). On the other hand, a quartz template (NIM-PH350, manufactured by NTT-ATN) pre-applied with a mold release agent (trade name "HD-1100Z", manufactured by Daikin Kasei Co., Ltd.) is applied to silicone rubber (thickness 0.2 mm). Was attached to a quartz exposure head of a simple imprinting apparatus as an adhesive layer. Next, after setting the pressure of the simple imprint apparatus to 0.2 MPa, the exposure head was lowered, the template and the experimental substrate were brought into close contact with each other via the photocurable composition for nanoimprint, and then UV exposure was performed for 15 seconds. .. After 15 seconds, the exposure stage was raised and the template was stripped 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-Tech), and the resist pattern formability is good when the resist pattern is not chipped and is rectangular in the 50 nm line-and-space pattern (A). It was judged that the resist pattern formability was poor (B) when there was a pattern loss.</p><p>[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 only 200 nm per minute. The second was etching under the condition that the silicon dioxide film was etched at 100 nm per minute. In any of the etchings, when the difference between the initial film thickness and the post-etching film thickness was less than 5 nm, the etching selectivity was judged to be good (A), and when the difference was 5 nm or more, it was judged to be defective (B). When it is judged that the etching selectivity is good, each of the above-mentioned inorganic film forming compositions functions well as a mask film when processing each film.</p><p><tables num="2"><img file="JP2012215877A_D0013.tif" /></tables></p><p> As is clear from the results shown in Table 2, the inorganic film-forming composition is excellent in etching selectivity, and when the inorganic film-forming composition is used, the resist pattern formed is excellent in resist pattern formability. I understood.</p>

The present invention can provide an inorganic film forming composition for a multilayer resist process, which is excellent in resist pattern forming property and etching selectivity, and a pattern forming method. Therefore, in the multilayer resist process using the composition, even when the organic film is thinned, the resist pattern disappears, loses its shape, bends, and the like can be suppressed, and faithful pattern transfer becomes possible. Therefore, the present invention can be extremely suitably used for manufacturing LSIs, which are expected to be further miniaturized in the future, particularly for forming fine contact holes and the like.