EUV resist underlayer film-forming composition

Abstract

To provide a composition for forming a resist underlayer film that enables the formation of a desired resist pattern, and a method for producing a resist pattern and a method for producing a semiconductor device, each of which uses the composition for forming a resist underlayer film.SOLUTION: A composition for forming an EUV resist underlayer film having a basic organic group substituted with a protective group on a side chain of a (meth)acrylic polymer and further including a solvent, the composition not including a polymer other than the (meth)acrylic polymer. The organic group is an acyloxy group that has an amino group substituted with a protective group, or that has a nitrogen-containing heterocycle substituted with a protective group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition used in lithography processes in semiconductor manufacturing, particularly in cutting-edge lithography processes (ArF, EUV, EB, etc.), and also to a method for producing a substrate with a resist pattern using the resist underlayer film, and a method for producing a semiconductor device. [Background technology]

[0002] In the manufacture of semiconductor devices, microfabrication by lithography using a resist composition has traditionally been performed. This microfabrication process involves forming a thin film of a photoresist composition on a semiconductor substrate, such as a silicon wafer, irradiating the substrate with actinic rays such as ultraviolet light through a mask pattern bearing a device pattern, developing the film, and etching the substrate using the resulting photoresist pattern as a protective film, thereby forming fine irregularities on the substrate surface corresponding to the pattern. In recent years, the integration density of semiconductor devices has increased, and in addition to the conventionally used i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm), the practical use of EUV light (wavelength 13.5 nm) or EB (electron beam) is being considered for cutting-edge microfabrication. As a result, poor resist pattern formation due to influences from the semiconductor substrate and other factors has become a major problem. To address this issue, methods of providing a resist underlayer film between the resist and the semiconductor substrate have been widely investigated. To address this issue, methods of providing a resist underlayer film between the resist and the semiconductor substrate have been widely investigated. Patent Document 1 discloses an additive for a resist underlayer film-forming composition for increasing the adhesion of a resist pattern formed on a resist underlayer film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 058189 Summary of the Invention [Problem to be solved by the invention]

[0004] The properties required for the resist underlayer film include, for example, not intermixing with the resist film formed on top (being insoluble in a resist solvent) and having a faster dry etching rate than the resist film.

[0005] In lithography involving EUV exposure, the line width of the formed resist pattern is 32 nm or less, and the resist underlayer film for EUV exposure is formed thinner than conventional films. When forming such a thin film, pinholes and aggregation are likely to occur due to the influence of the substrate surface and the polymer used, making it difficult to form a uniform film without defects.

[0006] On the other hand, when forming a resist pattern, a method is sometimes adopted in which the unexposed portions of the resist film are removed in the development step using a solvent capable of dissolving the resist film, usually an organic solvent, and the exposed portions of the resist film are left as a resist pattern. In such a negative development process, improving the adhesion of the resist pattern is a major challenge.

[0007] There is also a demand for suppressing deterioration of LWR (Line Width Roughness) during resist pattern formation, forming resist patterns with good rectangular shapes, and improving resist sensitivity.

[0008] An object of the present invention is to provide a composition for forming a resist underlayer film that can solve the above-mentioned problems and that can form a desired resist pattern, and a method for forming a resist pattern that uses the resist underlayer film-forming composition. [Means for solving the problem]

[0009] The present invention encompasses the following. [1] An EUV resist underlayer film-forming composition comprising a (meth)acrylic polymer having a basic organic group substituted with a protecting group on a side chain thereof, and further comprising an organic solvent, An EUV resist underlayer film-forming composition that does not contain any polymer other than the (meth)acrylic polymer. [2] The EUV resist underlayer film-forming composition according to [1], wherein the organic group is an acyloxy group having an amino group substituted with a protecting group, or an acyloxy group having a nitrogen-containing heterocycle substituted with a protecting group. [3] The EUV resist underlayer film-forming composition according to any one of [1] and [2], wherein the protecting group is selected from a tert-butoxycarbonyl group, a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, a 2,2,2-trichloroethoxycarbonyl group, and an allyloxycarbonyl group. [4] The EUV resist underlayer film-forming composition according to any one of [1] to [3], wherein the (meth)acrylic polymer is a polymer having a unit structure represented by the following formula (1): [ka] (In formula (1), R1 represents a hydrogen atom or a methyl group, L represents a divalent linking group, and X represents an acyloxy group having an amino group substituted with a protecting group or an acyloxy group having a nitrogen-containing heterocycle substituted with a protecting group.) [5] The EUV resist underlayer film-forming composition according to any one of [1] to [4], further comprising a crosslinking catalyst. [6] The EUV resist underlayer film-forming composition according to any one of [1] to [5], further comprising a crosslinking agent. [7] An EUV resist underlayer film, which is a fired product of a coating film made of the EUV resist underlayer film-forming composition according to any one of [1] to [6]. [8] A method for producing a patterned substrate, comprising the steps of: applying the EUV resist underlayer film-forming composition according to any one of [1] to [6] onto a semiconductor substrate and baking the composition to form an EUV resist underlayer film; applying an EUV resist onto the EUV resist underlayer film and baking the composition to form an EUV resist film; exposing the EUV resist underlayer film and the semiconductor substrate coated with the EUV resist; and developing and patterning the exposed EUV resist film. [9] forming an EUV resist underlayer film on a semiconductor substrate, the EUV resist underlayer film being composed of the EUV resist underlayer film-forming composition according to any one of [1] to [6]; forming an EUV resist film on the EUV resist underlayer film; a step of forming an EUV resist pattern by irradiating the EUV resist film with light or an electron beam and then developing it; forming a patterned EUV resist underlayer film by etching the EUV resist underlayer film through the formed EUV resist pattern; processing a semiconductor substrate using the patterned EUV resist underlayer film; A method for manufacturing a semiconductor device, comprising: [Effects of the Invention]

[0010] The EUV resist underlayer film-forming composition of the present invention is an EUV resist underlayer film-forming composition that has a basic organic group substituted with a protecting group in the side chain of a (meth)acrylic polymer and further contains an organic solvent, and is characterized by not containing a polymer other than the above (meth)acrylic polymer. The resist underlayer film produced using the composition of the present application has a basic organic group substituted with a protecting group in the side chain of the (meth)acrylic polymer. After the composition of the present application is applied to form a film and baked, amino groups are generated on the film surface. The adhesion to the resist is improved by these amino groups, so that a rectangular and good resist pattern can be created without so-called comet tailing or undercutting of the resist shape. By having such a configuration, the lithography resist underlayer film-forming composition of the present application can achieve suppression of deterioration of LWR and improvement of sensitivity during resist pattern formation. In particular, the EUV resist underlayer film-forming composition of the present application exhibits a more remarkable effect when an EUV exposure resist is used.

Brief Description of the Drawings

[0011] [Figure 1] It is a scanning microscope photograph from above the positive resist pattern for EUV of Example 1. [Figure 2] It is a scanning microscope photograph from above the positive resist pattern for EUV of Comparative Example 1. [Figure 3] It is a scanning microscope photograph from above the negative resist pattern for EUV of Example 1. [Figure 4] It is a scanning microscope photograph from above the negative resist pattern for EUV of Comparative Example 1.

Modes for Carrying Out the Invention

[0012] <EUV Resist Underlayer Film-Forming Composition> The EUV resist underlayer film-forming composition of the present application is an EUV resist underlayer film-forming composition that has a basic organic group substituted with a protecting group on the side chain of a (meth)acrylic polymer and further contains an organic solvent, and does not contain any polymer other than the (meth)acrylic polymer. In other words, the EUV resist underlayer film-forming composition of the present application contains only the polymer that has a basic organic group substituted with a protecting group on the side chain of the (meth)acrylic polymer, and does not contain any other polymers. The polymer contained in the EUV resist underlayer film-forming composition of the present application consists solely of the polymer that has a basic organic group substituted with a protecting group on the side chain of the (meth)acrylic polymer.

[0013] A (meth)acrylic polymer generally refers to a polymer having a unit structure derived from one or more monomers selected from (meth)acrylic acid, (meth)acrylic acid esters, and derivatives thereof. The (meth)acrylic polymer is preferably a vinyl polymer obtained by reacting an olefin or a (meth)acrylic polymer obtained by polymerizing a (meth)acrylate compound. In the present invention, a (meth)acrylate compound refers to both an acrylate compound and a methacrylate compound. For example, (meth)acrylic acid refers to acrylic acid and methacrylic acid. The polymer can be produced by a known method. The polymer may be linear or crosslinked, but is preferably linear.

[0014] 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, and cyclopentene. Examples of suitable solvents include hexane, 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 alone or in combination of two or more.

[0015] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, etc. are preferred, with propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate being particularly preferred.

[0016] The basic organic group referred to in the present invention refers to a monovalent saturated or unsaturated group containing carbon atoms, hydrogen atoms, and heteroatoms (e.g., at least one selected from the group consisting of oxygen atoms, sulfur atoms, and nitrogen atoms) and exhibiting basicity due to uneven distribution of electrons in the molecular structure caused by the heteroatoms. Preferably, the heteroatoms are at least two selected from the group consisting of oxygen atoms, sulfur atoms, and nitrogen atoms, or at least one selected from the group consisting of oxygen atoms and nitrogen atoms, and more preferably oxygen atoms and nitrogen atoms. Preferably, the organic group is an acyloxy group having an amino group substituted with a protecting group, or an acyloxy group having a nitrogen-containing heterocycle substituted with a protecting group.

[0017] The term "protecting group" as used herein refers to a group that binds to the amino group or nitrogen-containing heterocycle to prevent changes during a specific chemical reaction, and then is removed by a specific means to restore the original amino group or nitrogen-containing heterocycle. Suitable protecting groups include carbamate-based protecting groups such as t-butoxycarbonyl, benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl, and allyloxycarbonyl, sulfonamide-based protecting groups such as tosyl and nosyl, imide-based protecting groups such as phthaloyl, and trifluoroacetyl. For example, when the protecting group is a tert-butoxycarbonyl group, an acyloxy group having an amino group protected by the tert-butoxycarbonyl group or an acyloxy group having a nitrogen-containing heterocycle protected by the tert-butoxycarbonyl group can be represented, for example, by the following formulas (a) to (j): Here, the acyloxy group is represented by "-OC(=O)-R" (R represents an organic group having an amino group protected by a tert-butoxycarbonyl group or an organic group having a nitrogen-containing heterocycle protected by a tert-butoxycarbonyl group), and the tert-butoxycarbonyl group may be abbreviated as "t-Boc" or "Boc".

[0018] [ka]

[0019] The protecting group is preferably selected from the group consisting of a tert-butoxycarbonyl group, a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, a 2,2,2-trichloroethoxycarbonyl group, and an allyloxycarbonyl group, and among these, a tert-butoxycarbonyl group is preferred.

[0020] The (meth)acrylic polymer is preferably a polymer having a unit structure represented by the following formula (1).

[0021] [ka]

[0022] (In formula (1), R1 represents a hydrogen atom or a methyl group, L represents a divalent linking group, and X represents an acyloxy group having an amino group substituted with a protecting group or an acyloxy group having a nitrogen-containing heterocycle substituted with a protecting group.)

[0023] Preferably, the (meth)acrylic polymer of the present invention has a structural unit represented by the formula (1). The (meth)acrylic polymer may be a homopolymer in which one component monomer is polymerized, or a copolymer in which two or more component monomers are polymerized, but is preferably a homopolymer.

[0024] The (meth)acrylic polymer of the present invention may contain one or more polymers having a basic organic group substituted with a protecting group on the side chain of the (meth)acrylic polymer, but preferably contains no more than two types, and most preferably contains only one type.

[0025] The divalent linking group represented by L in formula (1) is not particularly limited, and examples thereof include a -C(=O)OR2- group and a phenylene group, in which R2 in the -C(=O)OR2- group represents an alkylene group having 1 to 10 carbon atoms, and some of the hydrogen atoms in the alkylene group may be substituted with a hydroxy group or a halogen atom.

[0026] Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, a cyclopropylene group, an n-butylene group, an isobutylene group, an s-butylene group, a t-butylene group, a cyclobutylene group, a 1-methyl-cyclopropylene group, a 2-methyl-cyclopropylene group, an n-pentylene group, a 1-methyl-n-butylene group, a 2-methyl-n-butylene group, a 3-methyl-n-butylene group, a 1,1-dimethyl-n-propylene group, a 1,2-dimethyl-n-propylene group, a 2,2-dimethyl-n-propylene group, and a 1-ethyl-n-propylene group. cyclopentylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-cyclobutylene, 1,2-dimethyl-cyclopropylene, 2,3-dimethyl-cyclopropylene, 1-ethyl-cyclopropylene, 2-ethyl-cyclopropylene, n-hexylene, 1-methyl-n-pentylene, 2-methyl-n-pentylene, 3-methyl-n-pentylene, 4-methyl-n-pentylene, 1,1-dimethyl-n-butylene, 1,2-dimethyl-n-butylene, 1,3-dimethyl-n-butylene, 2,2-dimethyl-n-butylene, 2,3-dimethyl-n-butylene, 3,3-dimethyl-n-butylene, 1-ethyl-n-butylene, 2-ethyl-n-butylene, 1,1,2-trimethyl-n-propylene, 1,2,2-trimethyl-n-propylene, 1-ethyl-1-methyl-n-propylene, 1-ethyl-2-methyl-n-propylene, cyclohexylene, 1-methyl-cyclopentylene, 2-methyl-cyclopentylene, 3-methyl-cyclopentylene, 1-ethyl-cyclobutylene, 2-ethyl-cyclobutylene group, 3-ethyl-cyclobutylene group, 1,2-dimethyl-cyclobutylene group, 1,3-dimethyl-cyclobutylene group, 2,2-dimethyl-cyclobutylene group, 2,3-dimethyl-cyclobutylene group, 2,4-dimethyl-cyclobutylene group, 3,3-dimethyl-cyclobutylene group, 1-n-propyl-cyclopropylene group, 2-n-propyl-cyclopropylene group, 1-isopropyl-cyclopropylene group, 2-isopropyl-cyclopropylene group, 1,2,2-trimethyl-cyclopropylene group, 1,2,3-trimethyl-cyclopropylene group, 2,2,Examples of the cyclopropylene group include a 3-trimethyl-cyclopropylene group, a 1-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-1-methyl-cyclopropylene group, a 2-ethyl-2-methyl-cyclopropylene group, a 2-ethyl-3-methyl-cyclopropylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, and an n-decanylene group.

[0027] Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0028] A meth(acrylic) polymer having a structural unit represented by the formula (1) can be obtained, for example, by reacting a (meth)acrylic polymer having an epoxy group at its terminal with a monomer that reacts with the epoxy group. Examples of such monomers include N-(tert-butoxycarbonyl)glycine, N-(tert-butoxycarbonyl)alanine, N-(tert-butoxycarbonyl)valine, N-(tert-butoxycarbonyl)leucine, N-(tert-butoxycarbonyl)isoleucine, N-(tert-butoxycarbonyl)methionine, N-(tert-butoxycarbonyl)serine, N-(tert-butoxycarbonyl)threon ... N-(tert-butoxycarbonyl)proline, N-(tert-butoxycarbonyl)-histidine, N-(tert-butoxycarbonyl)phenylalanine, N-(tert-butoxycarbonyl)tyrosine, N-(tert-butoxycarbonyl)tryptophan, O-benzyl-N-(tert-butoxycarbonyl)serine, N-(tert-butoxycarbonyl)aspartic acid 4-benzyl, N-(tert-butoxycarbonyl)glutamic acid 5-benzyl N-(tert-butoxycarbonyl)-N-benzyl cysteine, N-(tert-butoxycarbonyl)-O-benzyl threonine, N-(tert-butoxycarbonyl)-O-benzyl tyrosine, N-(tert-butoxycarbonyl)-O-tert-butyl tyrosine, N-(tert-butoxycarbonyl)-N-carbobenzoxylidine, N-(tert-butoxycarbonyl)-3, 4-difluorophenylalanine, N-(tert-butoxycarbonyl)-4-fluorophenylalanine, N-(tert-butoxycarbonyl)-N1-formyltryptophan, N-(tert-butoxycarbonyl)glutamine, N-(tert-butoxycarbonyl)-4-hydroxyproline, N-(tert-butoxycarbonyl)-4-nitrophenylalanine, N-(tert-butoxycarbonyl)-paratoluenesulfonylhistidine,

[0029] N-(benzyloxycarbonyl)glycine, N-(benzyloxycarbonyl)alanine, N-(benzyloxycarbonyl)valine, N-(benzyloxycarbonyl)leucine, N-(benzyloxycarbonyl)isoleucine, N-(benzyloxycarbonyl)methionine, N-(benzyloxycarbonyl)serine, N-(benzyloxycarbonyl)threonine, N-(benzyloxycarbonyl)proline, N-(benzyloxycarbonyl)histidine, N-(benzyloxycarbonyl)phenylalanine, N-(benzyloxycarbonyl)tyrosine, N-(benzyloxycarbonyl)tryptophan, O-benzyl-N-(benzyloxycarbonyl)serine, N-(benzyloxycarbonyl)4-benzyl aspartate, N-(benzyloxycarbonyl)5-benzyl glutamate, N-(benzyloxycarbonyl) N-(benzyloxycarbonyl)asparagine, N-(benzyloxycarbonyl)-S-benzylcysteine, N-(benzyloxycarbonyl)-O-benzylthreonine, N-(benzyloxycarbonyl)-O-benzyltyrosine, N-(benzyloxycarbonyl)-O-tert-butyltyrosine, N-(benzyloxycarbonyl)-N-carbobenzoxylidine, N-(benzyloxycarbonyl)-3,4-difluorophenylalanine, N-(benzyloxycarbonyl)-4-fluorophenylalanine, N-(benzyloxycarbonyl)-N1-formyltryptophan, N-(benzyloxycarbonyl)glutamine, N-(benzyloxycarbonyl)-4-hydroxyproline, N-(benzyloxycarbonyl)-4-nitrophenylalanine, N-(benzyloxycarbonyl)-paratoluenesulfonylhistidine,

[0030] N-(9-Fluorenylmethyloxycarbonyl)glycine, N-(9-Fluorenylmethyloxycarbonyl)alanine, N-(9-Fluorenylmethyloxycarbonyl)valine, N-(9-Fluorenylmethyloxycarbonyl)leucine, N-(9-Fluorenylmethyloxycarbonyl)isoleucine, N-(9-Fluorenylmethyloxycarbonyl)methionine, N-(9-Fluorenylmethyloxycarbonyl)serine, N-(9-Fluorenylmethyloxycarbonyl)threonine, N-(9-Fluorenylmethyl O-benzyl-N-(9-fluorenylmethyloxycarbonyl)serine, N-(9-fluorenylmethyloxycarbonyl)aspartic acid 4-benzyl, N-(9-fluorenylmethyloxycarbonyl)glutamic acid 5-benzyl N-(9-fluorenylmethyloxycarbonyl)asparagine, N-(9-fluorenylmethyloxycarbonyl)-S-benzylcysteine, N-(9-fluorenylmethyloxycarbonyl)-O-benzylthreonine, N-(9-fluorenylmethyloxycarbonyl)-O-benzyltyrosine, N-(9-fluorenylmethyloxycarbonyl)-O-tert-butyltyrosine, N-(9-fluorenylmethyloxycarbonyl)-N-carbobenzoxylidine, N-(9-fluorenylmethyloxycarbonyl)- 3,4-difluorophenylalanine, N-(9-fluorenylmethyloxycarbonyl)-4-fluorophenylalanine, N-(9-fluorenylmethyloxycarbonyl)-N1-formyltryptophan, N-(9-fluorenylmethyloxycarbonyl)glutamine, N-(9-fluorenylmethyloxycarbonyl)-4-hydroxyproline, N-(9-fluorenylmethyloxycarbonyl)-4-nitrophenylalanine, N-(9-fluorenylmethyloxycarbonyl)-paratoluenesulfonylhistidine,

[0031] N-(2,2,2-trichloroethoxycarbonyl)glycine, N-(2,2,2-trichloroethoxycarbonyl)alanine, N-(2,2,2-trichloroethoxycarbonyl)valine, N-(2,2,2-trichloroethoxycarbonyl)leucine, N-(2,2,2-trichloroethoxycarbonyl)isoleucine, N-(2,2,2-trichloroethoxycarbonyl)methionine, N-(2,2,2-trichloroethoxycarbonyl)serine, N-(2,2,2-trichloroethoxycarbonyl)threonine, N-(2,2,2-trichloroethoxycarbonyl) N-(2,2,2-trichloroethoxycarbonyl)proline, N-(2,2,2-trichloroethoxycarbonyl)histidine, N-(2,2,2-trichloroethoxycarbonyl)phenylalanine, N-(2,2,2-trichloroethoxycarbonyl)tyrosine, N-(2,2,2-trichloroethoxycarbonyl)tryptophan, O-benzyl-N-(2,2,2-trichloroethoxycarbonyl)serine, N-(2,2,2-trichloroethoxycarbonyl)aspartic acid 4-benzyl, N-(2,2,2-trichloroethoxycarbonyl)glutamic acid 5-benzyl N-benzyl, N-(2,2,2-trichloroethoxycarbonyl)asparagine, N-(2,2,2-trichloroethoxycarbonyl)-S-benzylcysteine, N-(2,2,2-trichloroethoxycarbonyl)-O-benzylthreonine, N-(2,2,2-trichloroethoxycarbonyl)-O-benzyltyrosine, N-(2,2,2-trichloroethoxycarbonyl)-O-tert-butyltyrosine, N-(2,2,2-trichloroethoxycarbonyl)-N-carbobenzoxylidine, N-(2,2,2-trichloroethoxycarbonyl )-3,4-difluorophenylalanine, N-(2,2,2-trichloroethoxycarbonyl)-4-fluorophenylalanine, N-(2,2,2-trichloroethoxycarbonyl)-N1-formyltryptophan, N-(2,2,2-trichloroethoxycarbonyl)glutamine, N-(2,2,2-trichloroethoxycarbonyl)-4-hydroxyproline, N-(2,2,2-trichloroethoxycarbonyl)-4-nitrophenylalanine, N-(2,2,2-trichloroethoxycarbonyl)-paratoluenesulfonylhistidine,

[0032] N-(Allyloxycarbonyl)glycine, N-(allyloxycarbonyl)alanine, N-(allyloxycarbonyl)valine, N-(allyloxycarbonyl)leucine, N-(allyloxycarbonyl)isoleucine, N-(allyloxycarbonyl)methionine, N-(allyloxycarbonyl)serine, N-(allyloxycarbonyl)threonine, N-(allyloxycarbonyl)proline, N-(allyloxycarbonyl)histidine, N-(allyloxycarbonyl)phenylalanine, N-(allyloxycarbonyl)tyrosine, N-(allyloxycarbonyl)tryptophan, O-benzyl-N-(allyloxycarbonyl)serine, N-(allyloxycarbonyl)4-benzyl aspartate, N-(allyloxycarbonyl)5-benzyl glutamate, N-(allyloxycarbonyl)a Examples include sparagine, N-(allyloxycarbonyl)-S-benzylcysteine, N-(allyloxycarbonyl)-O-benzylthreonine, N-(allyloxycarbonyl)-O-benzyltyrosine, N-(allyloxycarbonyl)-O-tert-butyltyrosine, N-(allyloxycarbonyl)-N-carbobenzoxylidine, N-(allyloxycarbonyl)-3,4-difluorophenylalanine, N-(allyloxycarbonyl)-4-fluorophenylalanine, N-(allyloxycarbonyl)-N1-formyltryptophan, N-(allyloxycarbonyl)glutamine, N-(allyloxycarbonyl)-4-hydroxyproline, N-(allyloxycarbonyl)-4-nitrophenylalanine, and N-(allyloxycarbonyl)-paratoluenesulfonylhistidine.

[0033] Of these, N-(tert-butoxycarbonyl)glycine, N-(tert-butoxycarbonyl)alanine, N-(tert-butoxycarbonyl)leucine, N-(tert-butoxycarbonyl)methionine, N-(tert-butoxycarbonyl)serine, N-(tert-butoxycarbonyl)proline, and N-(tert-butoxycarbonyl)-4-hydroxyproline are preferred.

[0034] The weight average molecular weight of the (meth)acrylic polymer is, for example, 2000 to 50000. The weight average molecular weight can be measured, for example, by gel permeation chromatography as described in the examples below.

[0035] The content ratio of the (meth)acrylic polymer in the entire resist underlayer film-forming composition is 0.01% by weight to 1.00% by weight, preferably 0.01% by weight to 0.90% by weight, preferably 0.01% by weight to 0.80% by weight, preferably 0.01% by weight to 0.70% by weight, preferably 0.01% by weight to 0.60% by weight, preferably 0.01% by weight to 0.50% by weight, preferably 0.01% by weight to 0.49% by weight, preferably 0.01% by weight to 0.45% by weight, preferably 0.01% by weight to 0.4% by weight, preferably 0.01% by weight to 0.3% by weight, and preferably 0.01% by weight to 0.2% by weight.

[0036] Examples of crosslinking catalysts (curing catalysts) that may be included as an optional component in the 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-toluenesulfonic acid), pyridinium p-hydroxybenzenesulfonic acid (pyridinium p-phenolsulfonate salt), pyridinium trifluoromethanesulfonic acid, 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 above crosslinking catalysts are used, the content of the crosslinking catalyst is, for example, 0.1% to 50% by mass, and preferably 1% to 30% by mass, relative to the crosslinking agent. Examples of crosslinking agents that may be optionally included in the 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. When the above crosslinking agents are used, the content of the crosslinking agent is, for example, 1% to 50% by mass, and preferably 5% to 30% by mass, relative to the polymer.

[0037] In the resist underlayer film forming composition of the present invention, in order to prevent the occurrence of pinholes, striations, etc., and further improve the coating property with respect to surface unevenness, a surfactant can be further added. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl allyl 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; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; nonionic surfactants; fluorine - based surfactants such as F-Top EF301, EF303, EF352 (manufactured by Tocem Products Co., Ltd., trade name), Megafac F171, F173, R - 30 (manufactured by Dainippon Ink and Chemicals, Inc., trade name), Fluorad FC430, FC431 (manufactured by Sumitomo 3M Limited, trade name), Asahi Guard AG710, Surflon S - 382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd., trade name); and organosiloxane polymer KP341 (manufactured by Shin - Etsu Chemical Co., Ltd.). The blending amount of these surfactants is usually 2.0 mass% or less, preferably 1.0 mass% or less, based on the total solid content of the resist underlayer film forming composition of the present invention. These surfactants may be added alone or in combination of two or more kinds.

[0038] <EUV Resist Underlayer Film, Method for Producing EUV Resist Underlayer Film> The resist underlayer film according to the present invention can be produced by applying the above-described resist underlayer film-forming composition onto a semiconductor substrate and baking it.

[0039] Examples of semiconductor substrates to which the resist underlayer film-forming composition of the present invention can be applied include silicon wafers, germanium wafers, and wafers of compound semiconductors such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride.

[0040] When a semiconductor substrate having an inorganic film formed on its surface is used, the inorganic film can be formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum deposition, or spin-coating (spin-on-glass: SOG). Examples of the inorganic film include polysilicon film, silicon oxide film, silicon nitride film, BPSG (Boro-Phospho Silicate Glass) film, titanium nitride film, titanium nitride oxide film, tungsten film, gallium nitride film, and gallium arsenide film.

[0041] The resist underlayer film-forming composition of the present invention is applied onto such a semiconductor substrate by a suitable application method such as a spinner or coater. The composition is then baked using a heating means such as a hot plate to form a resist underlayer film. The baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 120°C to 350°C and the baking time is 0.5 to 30 minutes, and more preferably, the baking temperature is 150°C to 300°C and the baking time is 0.8 to 10 minutes.

[0042] The thickness of the EUV resist underlayer film to be formed may be, for example, 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), The thicknesses of the resist underlayer film are 0.004 μm (4 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), and 0.005 μm (5 nm) to 0.02 μm (20 nm). If the baking temperature is lower than the above range, crosslinking may be insufficient. On the other hand, if the baking temperature is higher than the above range, the resist underlayer film may be decomposed by heat.

[0043] <Method for manufacturing a patterned substrate, and method for manufacturing a semiconductor device> The manufacturing method for a patterned substrate involves the following steps. Typically, a photoresist layer is formed on an EUV resist underlayer film. The photoresist formed on the EUV resist underlayer film by coating and baking using a method known per se is not particularly limited as long as it is sensitive to the light used for exposure. Both negative and positive photoresists can be used. Examples of suitable photoresists include positive photoresists composed of a novolac resin and a 1,2-naphthoquinone diazide sulfonic acid ester; chemically amplified photoresists composed of a binder having a group that decomposes in acid to increase the alkaline dissolution rate and a photoacid generator; chemically amplified photoresists composed of a low-molecular-weight compound that decomposes in acid to increase the alkaline dissolution rate of the photoresist, an alkali-soluble binder, and a photoacid generator; chemically amplified photoresists composed of a binder having a group that decomposes in acid to increase the alkaline dissolution rate, a low-molecular-weight compound that decomposes in acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator; and resists containing metal elements. Examples include V146G (trade name) manufactured by JSR Corporation, APEX-E (trade name) manufactured by Shipley Chemical Co., Ltd., PAR710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and AR2772 and SEPR430 (trade names) manufactured by Shin-Etsu Chemical Co., Ltd. Further examples include fluorine-containing polymer photoresists such as those described in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0044] Also, WO2019 / 188595, WO2019 / 187881, WO2019 / 187803, WO2019 / 167737, WO2019 / 167725, WO2019 / 187445, WO2019 / 167419, WO2019 / 123842, WO2019 / 054282, WO2019 / 058945, WO2019 / 058890, WO2019 / 039290, WO2019 / 044259, WO2019 / 044231, WO2019 / 026549, WO2018 / 193954, WO2019 / 123842 9 / 172054, WO2019 / 021975, WO2018 / 230334, WO2018 / 194123, JP 2018-180525, WO2018 / 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 2010-181 857, JP 2010-128369, WO2018 / 031896, JP 2019-113855, WO2017 / 156388, WO2017 / 066319, JP 2018-41099, WO2016 / 065120, WO2015 / 026482, JP 2016-29498, JP 2011-253185, etc., radiation-sensitive resin compositions, so-called resist compositions such as high-resolution patterning compositions based on organometallic solutions, and metal-containing resist compositions can be used, but are not limited to these.

[0045] Examples of the resist composition include the following. An actinic ray-sensitive or radiation-sensitive resin composition comprising: resin A having a repeating unit having an acid-decomposable group in which a polar group is protected with a protecting group that is cleaved by the action of an acid; and a compound represented by general formula (1):

[0046] [ka]

[0047] In the general formula (11), m represents an integer of 1 to 6. R1 and R2 each independently represent a fluorine atom or a perfluoroalkyl group. L1 represents -O-, -S-, -COO-, -SO2-, or -SO3-. L2 represents an alkylene group which may have a substituent or a single bond. W1 represents a cyclic organic group which may have a substituent. M + represents a cation.

[0048] A metal-containing film-forming composition for extreme ultraviolet or electron beam lithography, comprising 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.

[0049] A radiation-sensitive resin composition comprising a polymer having a first structural unit represented by the following formula (1) and a second structural unit represented by the following formula (2) containing an acid-dissociable group, and an acid generator:

[0050] [ka]

[0051] In formula (21), Ar is a group obtained by removing (n+1) hydrogen atoms from an arene having 6 to 20 carbon atoms. 1 is 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. When n is 2 or more, multiple R 1 are the same or different. R2 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. In formula (22), R 3 is a monovalent group having 1 to 20 carbon atoms and containing the above acid-dissociable group. Z is a single bond, an oxygen atom, or a sulfur atom. R 4 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0052] A resist composition comprising: 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 labile group; and an acid generator.

[0053] [ka] [In formula (II), R 2 represents an alkyl group having 1 to 6 carbon atoms which may have one or more halogen atoms, a hydrogen atom, or a halogen atom; X 1 is a single bond, -CO-O-* or -CO-NR 4 -*, * represents a bond to -Ar, R 4 represents 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 which may have one or more groups selected from the group consisting of a hydroxy group and a carboxyl group.]

[0054] A resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, The composition contains a base component (A) whose solubility in a developer changes under the action of an acid, and a fluorine additive component (F) that is decomposable in an alkaline developer, The resist composition is characterized in that the fluorine additive component (F) contains a fluorine resin component (F1) having a structural unit (f1) containing a base dissociable group and a structural unit (f2) containing a group represented by the following general formula (f2-r-1):

[0055] [ka]

[0056] [In formula (f2-r-1), Rf 21 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, a hydroxyalkyl group, or a cyano group. n" is an integer of 0 to 2. * is a bond.

[0057] The resist composition described above, wherein the structural unit (f1) includes a structural unit represented by the following general formula (f1-1) or a structural unit represented by the following general formula (f1-2):

[0058] [ka]

[0059] [In formulas (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-dissociable site. A aryl X is a divalent aromatic cyclic group which may have a substituent. 01 R is a single bond or a divalent linking group. 2 are each independently an organic group having a fluorine atom.

[0060] Examples of the resist film include the following. A resist film comprising a base resin containing a repeating unit represented by the following formula (a1) and / or a repeating unit represented by the following formula (a2), and a repeating unit that generates an acid bonded to the polymer main chain upon exposure:

[0061] [ka]

[0062] (In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. 1 and R 2are each independently a tertiary alkyl group having 4 to 6 carbon atoms. 3 are each independently a fluorine atom or a methyl group, and m is an integer of 0 to 4. X 1 X is a single bond, a phenylene group, or a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing at least one selected from an ester bond, a lactone ring, a phenylene group, and a naphthylene group. 2 is a single bond, an ester bond, or an amide bond.

[0063] Examples of resist materials include the following: A resist material comprising a polymer having a repeating unit represented by the following formula (a1) or (a2):

[0064] [ka]

[0065] (In formulas (b1) and (b2), R A is a hydrogen atom or a methyl group. 1 is a single bond or an ester group. 2 is a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 10 carbon atoms, and a part of the methylene groups constituting the alkylene group may be substituted with an ether group, an ester group or a lactone ring-containing group; and X 2 At least one hydrogen atom in X is substituted with a bromine atom. 3 Rf is a single bond, an ether group, an ester group, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and some of the methylene groups constituting the alkylene group may be substituted with an ether group or an ester group. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 1 ~R 5are each 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, in which some or all of the hydrogen atoms may be substituted with a hydroxy group, a carboxy 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, and in which some of the methylene groups constituting these groups may be substituted with an ether group, an ester group, a carbonyl group, a carbonate group, or a sulfonate ester group. 1 and R 2 may be bonded to form a ring together with the sulfur atom to which they are attached.

[0066] A resist material comprising a base resin containing a polymer containing a repeating unit represented by the following formula (a):

[0067] [ka]

[0068] (In formula (a), R A is a hydrogen atom or a methyl group. 1 is a hydrogen atom or an acid labile group. 2 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, or a halogen atom other than bromine. 1 X is a single bond, a phenylene group, or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms which may contain an ester group or a lactone ring. 2 is -O-, -O-CH2- or -NH-. m is an integer of 1 to 4. n is an integer of 0 to 3.

[0069] Examples of metal-containing resist compositions include the following: A coating comprising a metal oxo-hydroxone network having an organic ligand by a metal-carbon bond and / or a metal carboxylate bond.

[0070] An inorganic oxo / hydroxo-based composition.

[0071] Examples of the coating solution include the following. A coating solution comprising an organic solvent; a first organometallic composition represented by the formula RzSnO(2-(z / 2)-(x / 2))(OH)x (where 0 < z ≤ 2 and 0 < (z + x) ≤ 4), the formula R’nSnX4-n (where n = 1 or 2), or a mixture thereof, where R and R’ are independently hydrocarbyl groups having 1 to 31 carbon atoms, and X is a ligand having a hydrolyzable bond to Sn or a combination thereof; and a hydrolyzable metal compound represented by the formula MX’v (where M is a metal selected from Groups 2 to 16 of the Periodic Table of the Elements, v is a number from 2 to 6, and X’ is a ligand having a hydrolyzable M-X bond or a combination thereof).

[0072] A coating solution comprising an organic solvent and a first organometallic compound represented by the formula RSnO(3 / 2 - x / 2)(OH)x (where 0 < x < 3), wherein the solution contains about 0.0025 M to about 1.5 M of tin, R is an alkyl group or cycloalkyl group having 3 to 31 carbon atoms, and the alkyl group or cycloalkyl group is bonded to tin at a secondary or tertiary carbon atom.

[0073] An inorganic pattern-forming precursor aqueous solution comprising water, a metal oxide cation, a polyatomic inorganic anion, and a mixture with a radiation-sensitive ligand containing a peroxide group. etc. are included.

[0074] The exposure is carried out through a mask (reticle) to form a predetermined pattern. For example, i-line, KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet), or EB (electron beam) is used. Preferably, the resist underlayer film-forming composition of the present application is used for EUV (extreme ultraviolet) exposure. An alkaline developer is used for development, and the development temperature is appropriately selected from 5°C to 50°C and the development time is appropriately selected from 10 seconds to 300 seconds. Examples of the alkaline developer include aqueous solutions of inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and cyclic amines such as pyrrole and piperidine. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant can be added to the aqueous alkali solution. Among these, preferred developers are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants can be added to these developers. Instead of using an alkaline developer, development can be performed with an organic solvent such as butyl acetate, and the portions of the photoresist where the alkaline dissolution rate is not improved can be developed. Through the above steps, a substrate having the resist patterned thereon can be produced.

[0075] Next, the resist underlayer film is dry-etched using the formed resist pattern as a mask. At this time, if the inorganic film is formed on the surface of the semiconductor substrate used, the surface of the inorganic film is exposed, and if the inorganic film is not formed on the surface of the semiconductor substrate used, the surface of the semiconductor substrate is exposed. Thereafter, the substrate is processed by a method known per se (e.g., dry etching), thereby manufacturing a semiconductor device. [Example]

[0076] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these.

[0077] The weight-average molecular weights of the polymers shown in the following Synthesis Example 1 and Comparative Synthesis Example 1 in this specification are the results of measurement by gel permeation chromatography (hereinafter abbreviated as GPC). For the measurement, a GPC device manufactured by Tosoh Corporation was used, and the measurement conditions etc. are as follows. GPC columns: Shodex KF803L, Shodex KF802, Shodex KF801 (registered trademark) (Showa Denko K.K.) Column temperature: 40℃ Solvent: tetrahydrofuran (THF) Flow rate: 1.0ml / min Standard sample: Polystyrene (manufactured by Tosoh Corporation)

[0078] <Synthesis Example 1> 15.00 g of polyglycidyl methacrylate (Maruzen Petrochemical Co., Ltd.), 22.78 g of N-(tert-Butoxycarbonyl)-beta-alanine (Tokyo Chemical Industry Co., Ltd.), and 0.56 g of ethyltriphenylphosphonium bromide (Across Corporation) were dissolved in 100.72 g of propylene glycol monomethyl ether acetate. After purging the reaction vessel with nitrogen, the reaction was carried out at 80°C for 24 hours to obtain a polymer solution. The polymer solution did not become cloudy even when cooled to room temperature, demonstrating good solubility in propylene glycol monomethyl ether acetate. GPC analysis revealed that the polymer in the resulting solution had a weight-average molecular weight of 15,000 and a polydispersity of 1.68, calculated as standard polystyrene. The polymer obtained in this synthesis example has a structural unit represented by the following formula (1a):

[0079] [ka]

[0080] <Comparative Synthesis Example 1> 10.00 g of t-butoxy methacrylate (Tokyo Chemical Industry Co., Ltd.), 6.10 g of 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.), and 0.96 g of azobisisobutyronitrile (Tokyo Chemical Industry Co., Ltd.) were added to and dissolved in 73.00 g of propylene glycol monomethyl ether. After replacing the atmosphere in the reaction vessel with nitrogen, the reaction was carried out at 80°C for 24 hours to obtain a polymer solution. The polymer solution did not become cloudy even when cooled to room temperature, indicating good solubility in propylene glycol monomethyl ether. GPC analysis revealed that the polymer in the obtained solution had a weight-average molecular weight of 3690 and a polydispersity of 2.25, calculated as standard polystyrene. The polymer obtained in this synthesis example has structural units represented by the following formulas (1b) and (2b).

[0081] [ka]

[0082] Example 1 0.11 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries Co., Ltd.) and 0.012 g of p-phenolsulfonic acid pyridinium salt (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed with 3.12 g of the polymer solution containing 0.047 g of the polymer obtained in Synthesis Example 1 above, and 263.41 g of propylene glycol monomethyl ether and 29.89 g of propylene glycol monomethyl ether acetate were added and dissolved. The mixture was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to obtain a resist underlayer film-forming composition for lithography.

[0083] <Comparative Example 1> 0.11 g of tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries Co., Ltd.) and 0.012 g of p-phenolsulfonic acid pyridinium salt (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed with 3.12 g of the polymer solution containing 0.047 g of the polymer obtained in Comparative Synthesis Example 1 above, and 263.41 g of propylene glycol monomethyl ether and 29.89 g of propylene glycol monomethyl ether acetate were added and dissolved. The mixture was then filtered using a polyethylene microfilter with a pore size of 0.05 μm to obtain a resist underlayer film-forming composition for lithography.

[0084] [Photoresist solvent elution test] The resist underlayer film-forming compositions of Example 1 and Comparative Example 1 were each applied onto a silicon wafer, which was a semiconductor substrate, using a spinner. The silicon wafer was placed on a hot plate and baked at 215°C for 1 minute to form a resist underlayer film (film thickness: 5 nm). These resist underlayer films were immersed in ethyl lactate and propylene glycol monomethyl ether, solvents used in photoresists, and were confirmed to be insoluble in these solvents.

[0085] [Formation of a positive resist pattern using an electron beam lithography system] The resist underlayer film-forming compositions of Example 1 and Comparative Example 1 were applied to a silicon wafer using a spinner. The silicon wafer was baked on a hot plate at 215°C for 60 seconds to obtain a resist underlayer film with a thickness of 5 nm. A positive EUV resist solution was spin-coated onto the resist underlayer film and heated at 100°C for 60 seconds to form an EUV resist film. The resist film was exposed under specified conditions using an electron beam lithography system (ELS-G130). After exposure, the resist film was baked at 110°C for 60 seconds (PEB), cooled to room temperature on a cooling plate, and developed with an alkaline developer (2.38% TMAH), forming a resist pattern with 25 nm lines and a 50 nm pitch. A scanning electron microscope (CG4100, manufactured by Hitachi High-Technologies Corporation) was used to measure the resist pattern. In forming the above resist pattern, the exposure dose at which 25 nm lines / 50 nm pitch (line and space (L / S=1 / 1)) were formed was defined as the optimum exposure dose.

[0086] The photoresist patterns thus obtained were observed from above and evaluated. A resist pattern that was well formed was rated as "good," and an unfavorable state in which the resist pattern was peeled off and collapsed was rated as "collapse."

[0087] The results obtained are shown in Table 1. Scanning microscope photographs (top of pattern) of the resist pattern using the composition of Example 1 and the resist pattern of the comparative example are shown in FIGS.

[0088] [Table 1]

[0089] [Formation of a negative resist pattern using an electron beam lithography system] The resist underlayer film-forming compositions of Example 1 and Comparative Example 1 were each applied onto a silicon wafer using a spinner. The silicon wafer was baked on a hot plate at 215°C for 60 seconds to obtain a resist underlayer film with a thickness of 5 nm. A negative EUV resist solution was spin-coated onto the resist underlayer film and heated at 100°C for 60 seconds to form an EUV resist film. The resist film was exposed under specified conditions using an electron beam lithography system (ELS-G130). After exposure, the resist film was baked at 110°C for 60 seconds (PEB), cooled to room temperature on a cooling plate, and developed with butyl acetate to form a resist pattern with 25 nm lines and 50 nm pitch. A scanning electron microscope (CG4100, manufactured by Hitachi High-Technologies Corporation) was used to measure the resist pattern. In forming the resist pattern, the exposure dose that formed 25 nm lines and a 50 nm pitch (line and space (L / S=1 / 1)) was defined as the optimal exposure dose.

[0090] The photoresist patterns thus obtained were observed from above and evaluated. Resist patterns that were well formed with the same exposure dose were rated as "good," while those with residual patterns between the resist patterns were rated as "defective."

[0091] The results obtained are shown in Table 1. Scanning microscope photographs (top of pattern) of the resist pattern using the composition of Example 1 and the resist pattern of the comparative example are shown in FIGS.

[0092] [Table 2] [Industrial Applicability]

[0093] The resist underlayer film-forming composition according to the present invention can provide a composition for forming a resist underlayer film capable of forming a desired resist pattern, as well as a method for producing a substrate having a resist pattern and a method for producing a semiconductor device using the resist underlayer film-forming composition.

Claims

[Claim 1] An EUV resist underlayer film-forming composition comprising a (meth)acrylic polymer having a basic organic group substituted with a protecting group at a side chain thereof, and further comprising an organic solvent, An EUV resist underlayer film-forming composition that does not contain any polymer other than the (meth)acrylic polymer.

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