num="0079">With respect to other information about this polymer, the corresponding disclosure of WO2020/071361 is incorporated herein by reference.

The polymer may have an end blocked by a compound containing an aliphatic ring that optionally has a carbon-carbon bond interrupted by a heteroatom and is optionally substituted with a substituent.

The aliphatic ring is preferably a monocyclic or polycyclic aliphatic ring having 3 to 10 carbon atoms. The polycyclic aliphatic ring is preferably a bicyclo ring or a tricyclo ring.

The aliphatic ring preferably has at least one unsaturated bond.

Specific examples of the carboxy group-containing compounds containing an aliphatic ring that optionally has a carbon-carbon bond interrupted by a heteroatom and is optionally substituted with a substituent include the compounds shown below.

[Image Omitted]

With regard to other details about the compound containing an aliphatic ring that optionally has a carbon-carbon bond interrupted by a heteroatom and is optionally substituted with a substituent, the corresponding disclosure of PCT/JP2020/018436 is incorporated herein by reference.

The polymer may be a polymer having at an end of the polymer chain a structure described in WO2020/071361 and represented by the following formula (31) or (32):

[Image Omitted]

- wherein, in formula (31) and (32), X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, R₁is a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, each of R₂and R₃is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms and optionally being substituted, or an aryl group having 6 to 40 carbon atoms and optionally being substituted, each of n1 and n3 is independently an integer of 1 to 12, and n2 is an integer of 0 to 11.

The compound having the partial structure represented by formula (31) above is, for example, represented by the following formula (1-1):

[Image Omitted]

- wherein X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, R₁is a halogen atom, an alkyl group having 1 to 40 carbon atoms, or an alkoxy group having 1 to 40 carbon atoms, n1 is an integer of 1 to 12, and n2 is an integer of 0 to 11.

Specific examples of the compounds represented by formula (1-1) above include the followings.

[Image Omitted]

The compound having the partial structure represented by formula (32) above is, for example, represented by the following formula (2-1):

[Image Omitted]

- wherein X is a divalent organic group, A is an aryl group having 6 to 40 carbon atoms, each of R₂and R₃is independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and optionally being substituted, an aryl group having 6 to 40 carbon atoms and optionally being substituted, or a halogen atom, and n3 is an integer of 1 to 12.

Specific examples of the compounds represented by formula (2-1) above include the followings.

[Image Omitted]

With respect to other information about the present terminal structure, the corresponding disclosure of WO2020/071361 is incorporated herein by reference.

The end of the polymer may be represented by the following formula (41) or (42):

[Image Omitted]

- wherein, in formula (41) and (42), R₁represents an alkyl group having 1 to 6 carbon atoms and optionally having a substituent, a phenyl group, a pyridyl group, a halogeno group, or a hydroxy group, R₂represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a halogeno group, or an ester group represented by —C(═O)O—X wherein X represents an alkyl group having 1 to 6 carbon atoms and optionally having a substituent, R₃represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a halogeno group, R₄represents a direct bond or a divalent organic group having 1 to 8 carbon atoms, R₅represents a divalent organic group having 1 to 8 carbon atoms, A represents an aromatic ring or an aromatic heterocycle, t represents 0 or 1, and u represents 1 or 2.

With respect to the detailed information about the description of formula (41) and (42) above, the corresponding disclosure of WO2015/163195 is incorporated herein by reference.

The terminal structure of the reaction product of compound (A) and compound (B), which is represented by formula (41) or (42) above, may be produced by reacting the above-mentioned polymer and a compound represented by the following formula (41a) and/or a compound represented by the following formula (42a):

[Image Omitted]

- wherein the meanings of the characters and numerals in formula (41a) and (42a) are as defined above for formula (41) and (42).

Examples of the compound represented by formula (41a) include the compounds represented by the following formulae.

[Image Omitted]

Examples of the compound represented by formula (42a) include the compounds represented by the following formulae.

[Image Omitted]

<Organic Solvent>

Examples of the organic solvent contained in the EUV resist underlayer film-forming composition of the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents may be used each alone or in combination of two or more thereof.

Of these solvents, for example, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred. Especially preferred are propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate.

Examples of the crosslinking agent contained as an optional component in the EUV resist underlayer film-forming composition of the present invention include hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine, 1,3,4,6-tetrakis(methoxymethyl)glycoluril (tetramethoxymethylglycoluril) (POWDERLINK [registered trademark] 1174), 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, and 1,1,3,3-tetrakis(methoxymethyl)urea.

Further, the crosslinking agent in the present invention may be a nitrogen-containing compound having per molecule 2 to 6 substituents bonded to a nitrogen atom, which is described in WO2017/187969 and represented by the following formula (51):

[Image Omitted]

- wherein R₁represents a methyl group or an ethyl group.

The nitrogen-containing compound having 2 to 6 substituents represented by formula (51) above per molecule may be a glycoluril derivative represented by the following formula (1A):

[Image Omitted]

- wherein each of four R₁'s independently represents a methyl group or an ethyl group, and each of R₂and R₃independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.

Examples of the glycoluril derivative represented by formula (1A) include the compounds represented by the following formulae (1A-1) to (1A-6).

[Image Omitted]

The compound represented by formula (1A) may be obtained by allowing a nitrogen-containing compound having per molecule 2 to 6 substituents bonded to a nitrogen atom and represented by the following formula (52) to react with at least one compound represented by the following formula (53), to produce a nitrogen-containing compound having per molecule 2 to 6 substituents represented by formula (51) above:

[Image Omitted]

- wherein, in formula (52) and (53), R₁represents a methyl group or an ethyl group, and R₄represents an alkyl group having 1 to 4 carbon atoms.

The glycoluril derivative represented by formula (1A) may be obtained by reacting a glycoluril derivative represented by formula (2A) below and at least one compound represented by formula (53) above.

The nitrogen-containing compound having 2 to 6 substituents represented by formula (52) above per molecule is, for example, a glycoluril derivative represented by the following formula (2A):

[Image Omitted]

- wherein each of R₂and R₃independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and each R₄independently represents an alkyl group having 1 to 4 carbon atoms.

Examples of the glycoluril derivative represented by formula (2A) include the compounds represented by the following formulae (2A-1) to (2A-4). Further, examples of the compound represented by formula (53) include the compounds represented by the following formulae (3-1) and (3-2).

[Image Omitted]

With regard to other details about the nitrogen-containing compound having per molecule 2 to 6 substituents bonded to a nitrogen atom and represented by formula (51), the corresponding disclosure of WO2017/187969 is incorporated herein by reference.

When the crosslinking agent is used, the amount of the crosslinking agent contained is, for example, within the range of 1 to 50% by mass, preferably 5 to 30% by mass, based on the mass of the polymer.

Examples of the crosslinking catalyst (curing catalyst) contained as an optional component in the EUV resist underlayer film-forming composition of the present invention include sulfonic acid compounds and carboxylic acid compounds, such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, pyridinium p-hydroxybenzenesulfonate (pyridinium p-phenolsulfonate), pyridinium trifluoromethanesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

When the crosslinking catalyst is used, the amount of the crosslinking catalyst contained is, for example, within the range of 0.1 to 50% by mass, preferably 1 to 30% by mass, based on the mass of the crosslinking agent.

In the resist underlayer film-forming composition of the present invention, for further improving the application properties to prevent the occurrence of pinhole or striation and uneven surface, a surfactant may be further incorporated into the composition. Examples of surfactants include nonionic surfactants, e.g., polyoxyethylene alkyl ethers, such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers, such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate, fluorine surfactants, such as EFTOP EF301, EF303, EF352 (trade name, manufactured by Tohchem Products Co., Ltd.), MEGAFACE F171, F173, R-30 (trade name, manufactured by DIC Corporation), Fluorad FC430, FC431 (trade name, manufactured by Sumitomo 3M), AsahiGuard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (trade name, manufactured by AGC Inc.), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of the surfactant incorporated is generally 2.0% by mass or less, preferably 1.0% by mass or less, based on the total mass of the solids in the resist underlayer film-forming composition of the present invention. These surfactants may be used each alone or in combination of two or more thereof.

The EUV resist underlayer film of the present invention may be produced by applying the above-described EUV resist underlayer film-forming composition onto a semiconductor substrate and baking the applied composition.

Examples of semiconductor substrates to which the resist underlayer film-forming composition of the present invention is applied include a silicon wafer, a germanium wafer, and compound semiconductor wafers, such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride.

When a semiconductor substrate having an inorganic film formed on the surface thereof is used, the inorganic film is formed by, for example, an ALD (atomic layer deposition) method, a CVD (chemical vapor deposition) method, a reactive sputtering method, an ion plating method, a vacuum deposition method, or a spin coating method (spin on glass: SOG). Examples of the inorganic films include a polysilicon film, a silicon oxide film, a silicon nitride film, a BPSG (Boro-Phospho Silicate Glass) film, a titanium nitride film, a titanium nitride oxide film, a tungsten film, a gallium nitride film, and a gallium arsenide film.

The resist underlayer film-forming composition of the present invention is applied onto the above-mentioned semiconductor substrate by an appropriate application method, such as a spinner or a coater. Then, the applied composition is baked using a heating means, such as a hotplate, to form a resist underlayer film. Conditions for baking are appropriately selected from those at a baking temperature of 100 to 400° C. for a baking time of 0.3 to 60 minutes. Preferred conditions for baking are those at a baking temperature of 120 to 350° C. for a baking time of 0.5 to 30 minutes, and more preferred conditions are those at a baking temperature of 150 to 300° C. for a baking time of 0.8 to 10 minutes.

The thickness of the formed EUV resist underlayer film is, for example, within the range of 0.001 μm (1 nm) to 10 μm, 0.002 μm (2 nm) to 1 μm, 0.005 μm (5 nm) to 0.5 μm (500 nm), 0.001 μm (1 nm) to 0.05 μm (50 nm), 0.002 μm (2 nm) to 0.05 μm (50 nm), 0.003 μm (1 nm) to 0.05 μm (50 nm), 0.004 μm (4 nm) to 0.05 μm (50 nm), 0.005 μm (5 nm) to 0.05 μm (50 nm), 0.003 μm (3 nm) to 0.03 μm (30 nm), 0.003 μm (3 nm) to 0.02 μm (20 nm), or 0.005 μm (5 nm) to 0.02 μm (20 nm). When the temperature for baking is lower than the above-mentioned range, crosslinking becomes unsatisfactory. To the contrary, when the temperature for baking is higher than the above-mentioned range, the resist underlayer film is likely to be decomposed due to heat.

The method for producing a patterned substrate comprises the steps described below. Generally, a patterned substrate is produced by forming a photoresist layer on an EUV resist underlayer film. With respect to the photoresist formed on the EUV resist underlayer film by applying and baking by a known method, there is no particular limitation as long as it is sensitive to a light used in the exposure. Any of a negative photoresist and a positive photoresist can be used. They include, for example, a positive photoresist comprising a novolak resin and 1,2-naphthoquinonediazidosulfonate; a chemical amplification photoresist comprising a binder having a group which is decomposed due to an acid to increase the alkali solubility and a photo-acid generator; a chemical amplification photoresist comprising a low-molecular weight compound which is decomposed due to an acid to increase the alkali solubility of the photoresist, an alkali-soluble binder, and a photo-acid generator; a chemical amplification photoresist comprising a binder having a group which is decomposed due to an acid to increase the alkali solubility, a low-molecular weight compound which is decomposed due to an acid to increase the alkali solubility of the photoresist, and a photo-acid generator; and a resist containing a metal element. For example, they include trade name: V146G, manufactured by JSR Corporation, trade name: APEX-E, manufactured by Shipley Company, Inc., trade name: PAR710, manufactured by Sumitomo Chemical Co., Ltd., and trade name: AR2772, SEPR430, manufactured by Shin-Etsu Chemical Co., Ltd. Further, they include fluorine atom-containing polymer photoresists described in, for example, Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

Further, there may be used the resist composition, radiation-sensitive resin 15 composition, the so-called resist composition, e.g., a high resolution patterning composition based on an organometal solution, and metal-containing resist composition, which are disclosed in, for example, WO 2019/188595, WO 2019/187881, WO 2019/187803, WO 2019/167737, WO 2019/167725, WO 2019/187445, WO 2019/167419, WO 2019/123842, WO 2019/054282, WO 2019/058945, WO 2019/058890, WO 2019/039290, WO 2019/044259, WO 2019/044231, WO 2019/026549, WO 2018/193954, WO 2019/172054, WO 2019/021975, WO 2018/230334, WO 2018/194123, JP 2018-180525, WO 2018/190088, JP 2018-070596, JP 2018-028090, JP 2016-153409, JP 2016-130240, JP 2016-108325, JP 2016-047920, JP 2016-035570, JP 2016-035567, JP 2016-035565, JP 2019-101417, JP 2019-117373, JP 2019-052294, JP 2019-008280, JP 2019-008279, JP 2019-003176, JP 2019-003175, JP 2018-197853, JP 2019-191298, JP 2019-061217, JP 2018-045152, JP 2018-022039, JP 2016-090441, JP 2015-10878, JP 2012-168279, JP 2012-022261, JP 2012-022258, JP 2011-043749, JP 2010-181857, and JP 2010-128369, WO 2018/031896, JP 2019-113855, WO 2017/156388, WO 2017/066319, JP 2018-41099, WO 2016/065120, WO 2015/026482, and JP 2016-29498 and JP 2011-253185, but the resist is not limited to these compositions.

Examples of the resist compositions include the followings.

An active light-sensitive or radiation-sensitive resin composition, which comprises a resin A having a repeating unit having an acid decomposable group having a polar group protected by a protecting group capable of being eliminated by the action of an acid, and a compound represented by the following general formula (61):

[Image Omitted]

- wherein m represents an integer of 1 to 6,
- each of R₁and R₂independently represents a fluorine atom or a perfluoroalkyl group,
- L₁represents —O—, —S—, —COO—, —SO₂—, or —SO₃—,
- L₂represents an alkylene group optionally having a substituent, or a single bond,
- W₁represents a cyclic organic group optionally having a substituent, and
- M⁺represents a cation.

A metal-containing film-forming composition for extreme ultraviolet light or electron beam lithography, which comprises a compound having a metal-oxygen covalent bond, and a solvent, wherein the metal element constituting the compound belongs to Periods 3 to 7 of Groups 3 to 15 of the periodic table.

A radiation-sensitive resin composition, which comprises a polymer having a first structural unit represented by the following formula (71) and a second structural unit being represented by the following formula (72) and containing an acid dissociating group, and an acid generator:

[Image Omitted]

- wherein, in formula (71), Ar is a group obtained by removing (n+1) hydrogen atoms from an arene having 6 to 20 carbon atoms, R¹is a hydroxy group, a sulfanyl group, or a monovalent organic group having 1 to 20 carbon atoms, n is an integer of 0 to 11, wherein when n is 2 or more, more than one R¹are the same or different, and R²is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and
- wherein, in formula (72), R³is a monovalent group having 1 to 20 carbon atoms and containing the acid dissociating group, Z is a single bond, an oxygen atom, or a sulfur atom, and R⁴is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

A resist composition, which comprises a resin (A1) containing a structural unit having a cyclic carbonate structure, a structural unit represented by formula (II), and a structural unit having an acid destabilizing group, and an acid generator:

[Image Omitted]

- wherein R²represents an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom, a hydrogen atom, or a halogen atom, X¹represents a single bond, —CO—O—*, or —CO—NR⁴—* wherein * represents a bonding site with —Ar, R⁴represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Ar represents an aromatic hydrocarbon group having 6 to 20 carbon atoms and optionally having at least one group selected from the group consisting of a hydroxy group and a carboxyl group.

A resist composition, which generates an acid by exposure and changes in the solubility in a developer due to the action of the acid,

- wherein the resist composition comprises a base component (A) which changes in the solubility in a developer due to the action of an acid, and a fluorine additive component (F) which has decomposition properties with respect to an alkaline developer,
- wherein the fluorine additive component (F) comprises a fluorine resin component (F1) having a constitutional unit (f1) containing a base dissociating group and a constitutional unit (f2) containing a group represented by the following general formula (f2-r-1):

[Image Omitted]

- wherein each Rf²¹is independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, a hydroxyalkyl group, or a cyano group, n″ is an integer of 0 to 2, and * is a bonding site.

The above-mentioned constitutional unit (f1) may contain a constitutional unit represented by the following general formula (f1-1) or a constitutional unit represented by the following general formula (f1-2):

[Image Omitted]

- wherein, in formula (f1-1) and (f1-2), each R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, X is a divalent linking group having no acid dissociating site, A_arylis a divalent aromatic cyclic group optionally having a substituent, X₀₁is a single bond or a divalent linking group, and each R²is independently an organic group having a fluorine atom.

The metal-containing resist composition includes, for example, a coating containing a metal oxo-hydroxo network having an organic ligand through a metal carbon bond and/or a metal carboxylate bond, and an inorganic oxo/hydroxo base composition.

Examples of the resist materials include the followings.

A resist material, which comprises a polymer having a repeating unit represented by the following formula (a1) or (a2):

[Image Omitted]

- wherein, in formula (a1) and (a2), R^Ais a hydrogen atom or a methyl group, X¹is a single bond or an ester group, X²is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, wherein part of the methylene group constituting the alkylene group is optionally substituted with an ether group, an ester group, or a lactone ring-containing group, and wherein at least one hydrogen atom contained in X²is replaced by a bromine atom, X³is a single bond, an ether group, an ester group, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, wherein part of the methylene group constituting the alkylene group is optionally substituted with an ether group or an ester group, each of Rf¹to Rf⁴is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, wherein at least one of Rf¹to Rf⁴is a fluorine atom or a trifluoromethyl group, and wherein Rf¹and Rf²are optionally bonded together to form a carbonyl group, and each of R¹to R⁵is independently a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, a linear, branched, or cyclic alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aryloxyalkyl group having 7 to 12 carbon atoms, wherein part of or all of hydrogen atoms of the above groups are optionally replaced by a hydroxy group, a carboxyl group, a halogen atom, an oxo group, a cyano group, an amido group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group, wherein part of the methylene group constituting the above groups is optionally substituted with an ether group, an ester group, a carbonyl group, a carbonate group, or a sulfonate group, and wherein R¹and R²are optionally bonded together with the sulfur atom to which R¹and R²are bonded, to form a ring.

A resist material, which comprises a base resin containing a polymer having a repeating unit represented by the following formula (81):

[Image Omitted]

- wherein R^Ais a hydrogen atom or a methyl group, R¹is a hydrogen atom or an acid destabilizing group, R²is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a halogen atom other than bromine, X¹is a single bond, a phenylene group, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms and optionally having an ester group or a lactone ring, X²is —O—, —O—CH₂—, or —NH—, m is an integer of 1 to 4, and n is an integer of 0 to 3.

Examples of the resist films include the followings.

A resist film, which comprises a base resin having a repeating unit represented by the following formula (91) and/or a repeating unit represented by the following formula (92), and a repeating unit bonded to a polymer principal chain, which generates an acid by exposure:

[Image Omitted]

- wherein, in formula (91) and (92), each R^Ais independently a hydrogen atom or a methyl group, each of R¹and R²is independently a tertiary alkyl group having 4 to 6 carbon atoms, each R³is independently a fluorine atom or a methyl group, m is an integer of 0 to 4, X¹is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing at least one member selected from an ester linkage, a lactone ring, a phenylene group, and a naphthylene group, and X²is a single bond, an ester linkage, or an amide linkage.

Examples of the coating solutions include the followings.

A coating solution, which comprises an organic solvent; a first organometallic composition, which is represented by the formula: R_zSnO_{(2-(z/2)-(x/2))}(OH)_x(wherein 0<z≤2 and 0<(z+x)≤4), the formula: R′_nSnX_4-n(wherein n=1 or 2), or a mixture thereof, wherein each of R and R′ is independently a hydrocarbyl group having 1 to 31 carbon atoms, and X is a ligand having a hydrolyzable bond for Sn or a combination thereof; and a hydrolyzable metal compound represented by the formula: MX′_v(wherein M is a metal selected from Groups 2 to 16 of the periodic table of elements, v is a number of 2 to 6, and X′ is a ligand having a hydrolyzable M—X bond or a combination thereof).

A coating solution, which comprises an organic solvent and a first organometallic compound represented by the formula: RSnO_(3/2-x/2)(OH)_x(wherein 0<x<3), wherein the solution contains tin in an amount of about 0.0025 to about 1.5 M, and R is an alkyl group or cycloalkyl group having 3 to 31 carbon atoms, wherein the alkyl group or cycloalkyl group is bonded to tin at a secondary or tertiary carbon atom.

They include, for example, an aqueous solution of an inorganic pattern forming precursor, which comprises a mixture of water, metal suboxide cations, polyatomic inorganic anions, and a radiation-sensitive ligand containing a peroxide group.

Exposure through a mask (reticle) for forming a predetermined pattern is conducted, and, for example, an i-line, a KrF excimer laser, an ArF excimer laser, an EUV (extreme ultraviolet light), or an EB (electron beam) is used, and the resist underlayer film-forming composition of the present invention is preferably used in the EUV (extreme ultraviolet light) exposure. In development, an alkaline developer is used, and conditions are appropriately selected from those at a development temperature of 5 to 50° C. for a development time of 10 to 300 seconds. As an alkaline developer may be used, for example, an aqueous solution of an alkali, e.g., an inorganic alkali, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, or aqueous ammonia; a primary amine, such as ethylamine or n-propylamine; a secondary amine, such as diethylamine or di-n-butylamine; a tertiary amine, such as triethylamine or methyldiethylamine; an alcohol amine, such as dimethylethanolamine or triethanolamine; a quaternary ammonium salt, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, or choline; or a cyclic amine, such as pyrrole or piperidine. Moreover, an alcohol, such as isopropyl alcohol, or a surfactant, such as a nonionic surfactant may be added to the above-mentioned aqueous alkali solution in an appropriate amount before use. Of these, a preferred developer is a quaternary ammonium salt, and further preferred are tetramethylammonium hydroxide and choline. Furthermore, for example, a surfactant may be added to the above developers. Instead of the method using an alkaline developer, may be used a method, in which development is conducted using an organic solvent, such as butyl acetate, to develop a portion not improved in its alkali dissolution rate of the photoresist. The substrate having the resist patterned may be produced through the above-described steps.

Then, using the formed resist pattern as a mask, the resist underlayer film is subjected to dry etching. In this instance, the surface of the inorganic film is exposed, when the above-mentioned inorganic film is formed on the surface of the semiconductor substrate used, and, the surface of the semiconductor substrate is exposed, when the inorganic film is not formed on the surface of the semiconductor substrate used. Then, the substrate is subjected to the step of processing a substrate by a known method (such as a dry etching method), producing a semiconductor device.

EXAMPLES

Hereinbelow, the present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention.

The weight average molecular weight of the polymer shown in the following Synthesis Example 1 and Comparative Synthesis Example 1 in the present specification is the result of the measurement by gel permeation chromatography (hereinafter, referred to simply as “GPC”). In the measurement, a GPC apparatus, manufactured by Tosoh Corp., was used, and the conditions for the measurement and others are as follows.

- GPC Column: Shodex KF803L, Shodex KF802, Shodex KF801 [registered trademark] (Showa Denko K.K.)
- Column temperature: 40° C.
- Solvent: Tetrahydrofuran (THF)
- Flow rate: 1.0 ml/minute