Composition for forming resist underlayer film for electron beam or extreme ultraviolet lithography, resist underlayer film for electron beam or extreme ultraviolet lithography, and method for producing semiconductor substrate

Abstract

The present invention provides: a composition that is used for the formation of a resist underlayer film which is used in electron beam or extreme ultraviolet light lithography, and on which a fine resist pattern is able to be formed, while being capable of forming a resist underlayer film which is easily removed; and the like. A composition for forming a resist underlayer film for electron beam or extreme ultraviolet light lithography, said composition containing a polysiloxane compound having a first structural unit that is represented by formula (1), and a solvent. In formula (1), X is a group represented by formula (2); a is an integer from 1 to 3; R1 is a monovalent organic group having from 1 to 20 carbon atoms, a hydroxy group or a halogen atom; and b is an integer from 0 to 2, provided that (a + b) is 3 or less. In formula (2), R2 is a monovalent hydrocarbon group having from 1 to 20 carbon atoms; n is 1 or 2; R3 is a hydrogen atom or a monovalent organic group having from 1 to 20 carbon atoms; and L is a single bond or a divalent linking group.

Description

[Technical field]

[0001] The present invention relates to a resist underlayer film forming composition for electron beam or extreme ultraviolet lithography, a resist underlayer film for electron beam or extreme ultraviolet lithography, and a method for producing a semiconductor substrate. [Background technology]

[0002] A multi-layer resist process may be used for pattern formation in the manufacture of semiconductor substrates. In the multi-layer resist process, for example, a resist film laminated on a substrate via a resist underlayer film such as an organic underlayer film or a silicon-containing film is exposed and developed to obtain a resist pattern, etc., which is then used as a mask to perform etching to form a patterned substrate (see International Publication No. WO 2012 / 039337).

[0003] Recently, as semiconductor devices have become more highly integrated, there has been a trend toward shorter wavelength exposure light, from KrF excimer lasers (248 nm) and ArF excimer lasers (193 nm) to extreme ultraviolet light (13.5 nm, EUV), in order to form finer patterns. Also, lithography using electron beams is sometimes used to form finer patterns. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 039337 Summary of the Invention [Problem to be solved by the invention]

[0005] In a multilayer resist process, it is required to form a resist pattern having excellent rectangular cross-sectional shape without defects such as residues on a silicon-containing film that is a resist underlayer film. However, even in conventional electron beam or extreme ultraviolet lithography, it is difficult to form a fine resist pattern with a good shape. In particular, the finer the resist pattern formed, the more likely the pattern collapses during development. In addition, in the manufacturing process of semiconductor substrates, etc., the resist underlayer film is removed using a removal solution. At this time, it is required to easily remove the resist underlayer film while suppressing damage to the substrate.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition which is used for forming a resist underlayer film in electron beam or extreme ultraviolet lithography, and which is capable of forming a resist underlayer film which can form a fine resist pattern on the resist underlayer film formed and which can be easily removed; a resist underlayer film formed from such a composition; and a method for manufacturing a semiconductor substrate using such a composition. [Means for solving the problem]

[0007] The invention made to solve the above-mentioned problems is a resist underlayer film-forming composition for electron beam or extreme ultraviolet lithography, which contains a polysiloxane compound having a first structural unit represented by the following formula (1) (hereinafter also referred to as "compound [A]") and a solvent (hereinafter also referred to as "solvent [B]"). [ka] In formula (1), X is a group represented by the following formula (2). a is an integer of 1 to 3. When a is 2 or more, multiple Xs are the same or different. R 1 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R 1 are the same or different, provided that a+b is 3 or less. [ka] (In formula (2), R 2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, multiple R 2 are the same or different. R 3 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent linking group. * indicates the bonding site with the silicon atom in the above formula (1).

[0008] Another invention made to solve the above problems is a resist underlayer film for electron beam or extreme ultraviolet lithography, which is formed from the resist underlayer film forming composition for electron beam or extreme ultraviolet lithography.

[0009] Still another invention made to solve the above problems is a method for producing a semiconductor substrate, comprising the steps of: applying a resist underlayer film-forming composition directly or indirectly to a substrate; heating the coating film formed by the resist underlayer film-forming composition application step; applying a resist film-forming composition directly or indirectly to the resist underlayer film formed by the heating step; exposing the resist film formed by the resist film-forming composition application step to an electron beam or extreme ultraviolet light; and developing the exposed resist film, wherein the resist underlayer film-forming composition is the resist underlayer film-forming composition for electron beam or extreme ultraviolet light lithography described above. Effect of the Invention

[0010] According to the present invention, it is possible to provide a composition which is used for forming a resist underlayer film in electron beam or extreme ultraviolet lithography, which is capable of forming a fine resist pattern on the resist underlayer film formed and which is capable of forming a resist underlayer film which can be easily removed, a resist underlayer film formed from such a composition, and a method for manufacturing a semiconductor substrate using such a composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The resist underlayer film-forming composition for electron beam or extreme ultraviolet lithography (hereinafter also referred to as "resist underlayer film-forming composition"), the resist underlayer film for electron beam or extreme ultraviolet lithography (hereinafter also referred to as "resist underlayer film"), and the method for producing a semiconductor substrate of the present invention will be described in detail below.

[0012] <Resist underlayer film forming composition> The resist underlayer film forming composition contains a compound [A] and a solvent [B]. The resist underlayer film forming composition may contain other optional components (hereinafter, also simply referred to as "optional components") within a range that does not impair the effects of the present invention.

[0013] The resist underlayer film-forming composition contains the compound [A] and the solvent [B], and thus in electron beam or extreme ultraviolet lithography, a fine resist pattern can be formed on the resist underlayer film formed. Furthermore, the resist underlayer film (silicon-containing film) formed by the resist underlayer film-forming composition has excellent removability (film removability) by a removal solution containing an acid. The reason why the resist underlayer film-forming composition exhibits the above-mentioned effects is not necessarily clear, but can be presumed, for example, as follows. When forming a resist underlayer film, the coating film of the resist underlayer film-forming composition is usually heated for the purpose of removing the solvent, curing, etc. During this heating, in the group represented by the above formula (2) possessed by the compound [A], the protecting group (R 2 ) and decarboxylation (CO2), i.e. -COOR 2The elimination of the group represented by occurs, resulting in the formation of a primary or secondary amino group. When these basic amino groups are present on the surface of the resist underlayer film, it is possible to capture the acid in the resist film in contact with the surface of the resist underlayer film, and therefore it is believed that even in fine resist patterns formed by electron beam or extreme ultraviolet lithography, the rectangularity of the cross-sectional shape is excellent. Specifically, for example, in the case of a positive type using an alkaline developer, the acid in the resist film is captured on the surface of the resist underlayer film in the unexposed portion, so that the cross-sectional shape of the bottom of the resist pattern is unlikely to be hollowed out, and the collapse of the resist pattern is also suppressed. In addition, in the case of a negative type using an organic solvent developer, it is believed that the acid in the resist film is captured on the surface of the resist underlayer film in the unexposed portion, so that residues are unlikely to remain during development, and a resist pattern with excellent rectangularity of the cross-sectional shape can be formed. From these reasons, it is presumed that the use of the resist underlayer film forming composition can form a fine resist pattern on the resist underlayer film. In addition, since the amino group is present in the resist underlayer film formed, it is believed that the solubility in a removal solution containing an acid is improved, and therefore the film removability can be improved.

[0014] Hereinafter, each component contained in the resist underlayer film-forming composition will be described.

[0015] [[A] compound] The compound [A] is a polysiloxane compound having a first structural unit (hereinafter also referred to as "structural unit (I)") represented by the following formula (1) described later. In this specification, the term "polysiloxane compound" means a compound containing a siloxane bond (-Si-O-Si-). The compound [A] may have structural units other than the structural unit (I) as long as the effects of the present invention are not impaired.

[0016] Each structural unit contained in the compound [A] will be described below.

[0017] (Structural unit (I)) The structural unit (I) is a structural unit represented by the following formula (1): The compound [A] can have one type or two or more types of the structural unit (I).

[0018] [ka]

[0019] In formula (1), X is a group represented by the following formula (2): a is an integer of 1 to 3. When a is 2 or more, multiple Xs are the same or different. R 1 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R 1 are the same or different, provided that a+b is 3 or less.

[0020] [ka]

[0021] In formula (2), R 2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, multiple R 2 are the same or different. R 3 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent linking group. * indicates the bonding site with the silicon atom in the above formula (1).

[0022] In this specification, the term "organic group" refers to a group containing at least one carbon atom, and the term "number of carbon atoms" refers to the number of carbon atoms constituting the group.

[0023] R 1Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the formula (I) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group containing a divalent heteroatom-containing group between the carbon-carbon bond of this hydrocarbon group (hereinafter also referred to as "group (α)"), a group in which some or all of the hydrogen atoms of the above-mentioned hydrocarbon group or the above-mentioned group (α) are substituted with a monovalent heteroatom-containing group (hereinafter also referred to as "group (β)"), and a group in which the above-mentioned hydrocarbon group, the above-mentioned group (α) or the above-mentioned group (β) is combined with a divalent heteroatom-containing group (hereinafter also referred to as "group (γ)"). 1 The monovalent organic group having 1 to 20 carbon atoms represented by the following formula does not include the group represented by the above formula (2).

[0024] In this specification, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" may be a saturated or unsaturated hydrocarbon group. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not include a cyclic structure and is composed only of a linear structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it is not necessary for the alicyclic structure to be composed only of the alicyclic structure, and it may include a linear structure as a part of the alicyclic structure. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, it is not necessary for the alicyclic structure to be composed only of the aromatic ring structure, and it may include a linear structure or an alicyclic structure as a part of the alicyclic structure.

[0025] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0026] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, iso-butyl, and tert-butyl; alkenyl groups such as ethenyl, propenyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0027] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group, a cyclohexyl group, etc.; polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group, etc.; monocyclic alicyclic unsaturated hydrocarbon groups such as a cyclopentenyl group, a cyclohexenyl group, etc.; and polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group, a tricyclodecenyl group, a tetracyclododecenyl group, etc.

[0028] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group, and aralkyl groups such as a benzyl group, a phenethyl group, a naphthylmethyl group, and an anthrylmethyl group.

[0029] Examples of heteroatoms constituting the divalent and monovalent heteroatom-containing groups include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, etc. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0030] Examples of the divalent heteroatom-containing group include -O-, -C(=O)-, -S-, -C(=S)-, -NR'-, and combinations of two or more of these, where R' is a hydrogen atom or a monovalent hydrocarbon group.

[0031] Examples of the monovalent heteroatom-containing group include a halogen atom, a hydroxy group, a carboxy group, a cyano group, an amino group, and a sulfanyl group.

[0032] R 1Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0033] R 1 is preferably a monovalent organic group having 1 to 20 carbon atoms, more preferably a monovalent chain hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent group in which some or all of the hydrogen atoms of a monovalent hydrocarbon group have been substituted with a monovalent heteroatom-containing group, more preferably an alkyl group or an aryl group, and further preferably a methyl group, an ethyl group, or a phenyl group.

[0034] R 2 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include the above-mentioned R 1 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula include the same groups as those exemplified above.

[0035] R 2 is preferably a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and more preferably a monovalent chain hydrocarbon group having 1 to 20 carbon atoms.

[0036] R 2 When R is a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, the chain hydrocarbon group is preferably bonded to an oxygen atom via a tertiary carbon atom. That is, the chain hydrocarbon group is preferably a tertiary chain hydrocarbon group. In addition, the chain hydrocarbon group is preferably an alkyl group. That is, R 2 When R is a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, this chain hydrocarbon group is more preferably a tertiary alkyl group, further preferably a tertiary alkyl group having 4 to 8 carbon atoms, even more preferably a tertiary alkyl group having 4 to 6 carbon atoms, and particularly preferably a t-butyl group. 2 Regardless of the type of hydrocarbon group, it is preferable that is bonded to an oxygen atom via a tertiary carbon atom, that is, it is a tertiary hydrocarbon group.

[0037] R 2 When R is such a tertiary hydrocarbon group, the R 2This efficiently causes elimination of the group, etc., and makes it easier for amino groups to be present on the surface of the resist underlayer film, thereby improving the rectangularity of the resist pattern formed on the resist underlayer film, the ability to suppress collapse of the resist pattern, and the removability of the resist underlayer film.

[0038] R 3 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (I) include the above-mentioned R 1 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the formula (I) include the same groups as those exemplified above. 3 The monovalent organic group having 1 to 20 carbon atoms represented by the formula: -COO-R 2 The group represented by the following formula is not included.

[0039] R 3 R is preferably a monovalent organic group having 1 to 20 carbon atoms, more preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, still more preferably a chain hydrocarbon group or an alicyclic hydrocarbon group, even more preferably a chain hydrocarbon group, and still more preferably an alkyl group. 3 The group represented by the following formula (1) preferably has 1 to 8 carbon atoms, and more preferably has 1 to 4 carbon atoms.

[0040] R 3 When R is such a group, the basicity of the group (amino group) generated by heating is increased, and the effects of the resist underlayer film forming composition, such as the rectangularity of the resist pattern formed on the resist underlayer film, the ability to suppress collapse of the resist pattern, and the removability of the resist underlayer film, are further improved. 3 When is a hydrocarbon group, the hydrophobicity of the resist underlayer film is increased, thereby improving adhesion between the resist underlayer film and the resist pattern, and particularly suppressing the occurrence of collapse of the resist pattern during alkaline development.

[0041] Examples of the divalent linking group represented by L include divalent organic groups having 1 to 20 carbon atoms. Examples of the divalent organic group having 1 to 20 carbon atoms include the above-mentioned R 1 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula (I) include a group in which one hydrogen atom has been removed from the monovalent organic groups exemplified as the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula (I):

[0042] L is preferably a divalent hydrocarbon group having 1 to 20 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 20 carbon atoms, and further preferably an alkanediyl group having 1 to 20 carbon atoms. The number of carbon atoms in the group represented by L is preferably 1 to 12, and more preferably 1 to 6. A more preferred form of the group represented by L is -(CH2) m -(m is an integer of 1 to 6).

[0043] As a, 1 or 2 is preferable, and 1 is more preferable.

[0044] b is preferably 0 or 1, and more preferably 0.

[0045] n is preferably 1. When n is 1, R 3 When is an organic group, the amino group generated by heating becomes a secondary amino group. In general, secondary amino groups are more basic than primary amino groups. The generation of such highly basic amino groups improves the rectangularity of the resist pattern formed on the resist underlayer film, the ability to suppress the collapse of the resist pattern, and the removability of the resist underlayer film. In addition, since secondary amino groups are generally more hydrophobic than primary amino groups, the adhesion between the resist underlayer film and the resist pattern is improved, and the occurrence of the collapse of the resist pattern, especially during alkaline development, is suppressed.

[0046] Examples of the structural unit (I) include structural units derived from compounds represented by the following formulas (1-1) to (1-19).

[0047] [ka]

[0048] The lower limit of the content of the structural unit (I) in the [A] compound is preferably 0.1 mol%, more preferably 1 mol%, even more preferably 2 mol%, and even more preferably 3 mol% based on the total structural units constituting the [A] compound. The upper limit of the content of the structural unit (I) is preferably 80 mol%, more preferably 50 mol%, and even more preferably 20 mol%. By having the content of the structural unit (I) within the above range, when forming a resist pattern on the resist underlayer film by electron beam or extreme ultraviolet lithography, a fine resist pattern with excellent cross-sectional rectangularity and less prone to collapse can be formed, and the film removability is also improved.

[0049] (Other structural units) Examples of the other structural unit include a second structural unit represented by the following formula (3) (hereinafter also referred to as "structural unit (II)") and a third structural unit represented by the following formula (4) (hereinafter also referred to as "structural unit (III)"). When the compound [A] has the structural unit (II), the storage stability and coatability of the resist underlayer film-forming composition can be improved. When the compound [A] has the structural unit (III), the oxygen gas etching resistance of the resist underlayer film formed by the resist underlayer film-forming composition can be improved.

[0050] [ka]

[0051] In the above formula (3), R 4 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. c is an integer of 1 to 3. When c is 2 or more, multiple R 4 are the same or different from each other.

[0052] R 4 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (I) include the above-mentioned R 1 Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the following formula include the same groups as those exemplified above.

[0053] R 4 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0054] R 4 R4 is preferably a hydrocarbon group, more preferably an alkyl group or an aryl group. The group represented by R4 preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms.

[0055] As c, 1 is preferable.

[0056] When the compound [A] has a structural unit (II) as another structural unit, the lower limit of the content of the structural unit (II) is preferably 0.1 mol%, more preferably 1 mol%, and even more preferably 2 mol%, 3 mol%, or 5 mol% based on the total structural units constituting the compound [A]. The upper limit of the content is preferably 40 mol%, more preferably 30 mol%, and even more preferably 20 mol%.

[0057] [ka]

[0058] When the compound [A] has the structural unit (III) as another structural unit, the lower limit of the content of the structural unit (III) is preferably 30 mol%, more preferably 40 mol%, and even more preferably 50 mol%, 60 mol% or 70 mol% based on the total structural units constituting the compound [A]. The upper limit of the content is preferably 95 mol%, more preferably 90 mol%, and even more preferably 85 mol%.

[0059] The lower limit of the total content of the structural unit (I), the structural unit (II) and the structural unit (III) relative to all structural units constituting the compound [A] is preferably 80 mol%, more preferably 90 mol%, and in some cases even more preferably 95 mol% or 99 mol%. The upper limit of the total content may be 100 mol%.

[0060] The lower limit of the content of the compound [A] in the resist underlayer film forming composition is preferably 0.1 mass%, more preferably 0.3 mass%, and even more preferably 0.5 mass%, based on the total components contained in the resist underlayer film forming composition. The upper limit of the content is preferably 10 mass%, more preferably 5 mass%, more preferably 3 mass%, and even more preferably 2 mass%.

[0061] The lower limit of the content of the compound [A] in the total solid content of the resist underlayer film forming composition is preferably 50 mass%, more preferably 70 mass%, and even more preferably 80 mass%, 90 mass%, or 95 mass%. The upper limit of the content is preferably 100 mass%, and may be 99 mass% or 95 mass%. The total solid content refers to all components other than the solvent [B] and water [D].

[0062] The compound [A] is preferably in the form of a polymer. In this specification, the term "polymer" refers to a compound having two or more structural units, and when two or more identical structural units are consecutive in a polymer, this structural unit is also referred to as a "repeating unit". When the compound [A] is in the form of a polymer, the lower limit of the weight average molecular weight (Mw) of the compound [A] in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 1,000, more preferably 1,200, and even more preferably 1,500. The upper limit of the Mw is preferably 10,000, more preferably 5,000, and even more preferably 3,000.

[0063] In this specification, the Mw of compound [A] is a value measured by gel permeation chromatography (GPC) using Tosoh Corporation's GPC columns (two "G2000HXL", one "G3000HXL" and one "G4000HXL") under the following conditions. Eluent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0064] The [A] compound can be synthesized by a conventional method using monomers that provide each structural unit. For example, the monomer that provides the structural unit (I) and, if necessary, monomers that provide other structural units can be synthesized by hydrolysis and condensation in a solvent in the presence of a catalyst such as oxalic acid and water. It is believed that each monomer is incorporated into the [A] compound regardless of its type through the hydrolysis and condensation reaction. Therefore, the content ratio of the structural unit (I) and other structural units in the synthesized [A] compound is usually equivalent to the ratio of the amount of each monomer used in the synthesis reaction.

[0065] [[B] Solvent] The solvent [B] is not particularly limited, and examples thereof include alcohol solvents, ketone solvents, ether solvents, ester solvents, and nitrogen-containing solvents. The solvent [B] is usually an organic solvent. The resist underlayer film-forming composition may contain one or more solvents [B].

[0066] Examples of the alcohol solvent include monoalcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, and iso-butanol, and polyhydric alcohol solvents such as ethylene glycol, 1,2-propylene glycol, diethylene glycol, and dipropylene glycol.

[0067] Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-butyl ketone, and cyclohexanone.

[0068] Examples of ether solvents include ethyl ether, isopropyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and tetrahydrofuran.

[0069] Examples of ester-based solvents include ethyl acetate, γ-butyrolactone, n-butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, ethyl propionate, n-butyl propionate, methyl lactate, and ethyl lactate.

[0070] Examples of nitrogen-containing solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0071] Among these, ether-based solvents or ester-based solvents are preferred, and ether-based solvents having a glycol structure or ester-based solvents having a glycol structure are more preferred because of their excellent film-forming properties.

[0072] Examples of ether solvents having a glycol structure and ester solvents having a glycol structure include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc. Among these, propylene glycol monomethyl ether acetate or propylene glycol monoethyl ether is preferred.

[0073] The lower limit of the content of the solvent [B] in the resist underlayer film-forming composition is preferably 90 mass%, more preferably 92.5 mass%, and even more preferably 95 mass%, based on all components contained in the resist underlayer film-forming composition. The upper limit of the content is preferably 99.9 mass%, more preferably 99.5 mass%, and even more preferably 99 mass%.

[0074] (optional ingredient) Examples of the optional components include an acid generator, a basic compound (including a base generator), a radical generator, a surfactant, colloidal silica, colloidal alumina, an organic polymer, water, etc. The resist underlayer film forming composition may contain one or more optional components.

[0075] In the case where the resist underlayer film-forming composition contains an optional component, the content ratio of the optional component in the resist underlayer film-forming composition can be appropriately determined according to the type of the optional component used, and within a range that does not impair the effects of the present invention.

[0076] [[C] Acid generator] When the resist underlayer film forming composition contains the acid generator (C), the curability of the resist underlayer film forming composition is improved and intermixing between the resist underlayer film and the resist film can be suppressed.

[0077] The acid generator [C] is a component that generates an acid upon exposure to light or heating. When the film-forming composition contains an acid generator, the curing reaction of the compound [A] can be promoted even at relatively low temperatures (including room temperature).

[0078] Examples of the acid generator that generates an acid upon exposure to light include the acid generators described in paragraphs

[0077] to

[0081] of JP-A-2004-168748.

[0079] Examples of acid generators that generate acid upon heating include onium salt-based acid generators exemplified as photoacid generators in the above-mentioned JP-A-2004-168748, 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkylsulfonates.

[0080] When the resist underlayer film forming composition contains an acid generator [C], the lower limit of the content of the acid generator [C] in the resist underlayer film forming composition is, for example, preferably 0.001 mass% and more preferably 0.01 mass% based on the total components contained in the resist underlayer film forming composition. The upper limit of the content is preferably 1 mass%, more preferably 0.5 mass%, and even more preferably 0.1 mass%. By setting the content of the acid generator [C] to the lower limit or more, it is possible to further increase the curability. By setting the content of the acid generator [C] to the upper limit or less, it becomes easier to keep the surface of the resist underlayer film basic, and the rectangularity of the resist pattern formed on the resist underlayer film, the ability to suppress collapse of the resist pattern, and the removability of the resist underlayer film are improved.

[0081] [[D]Water] When the resist underlayer film forming composition contains water [D], the compound [A] is hydrated, improving storage stability. In addition, when the resist underlayer film forming composition contains water [D], curing during the formation of the resist underlayer film is promoted, and a dense resist underlayer film can be obtained. Water [D] is not included in the solvent [B].

[0082] When the resist underlayer film forming composition contains water [D], the lower limit of the content of water [D] in the resist underlayer film forming composition is, for example, preferably 0.1 mass %, more preferably 0.2 mass %, based on all components contained in the resist underlayer film forming composition. The upper limit of the content is preferably 20 mass %, more preferably 5 mass %.

[0083] <Method for preparing resist underlayer film-forming composition> The method for preparing the resist underlayer film-forming composition is not particularly limited, and the composition can be prepared according to a conventional method. For example, the composition can be prepared by mixing a solution of the compound [A], a solvent [B], and an optional component as required in a predetermined ratio, and preferably filtering the resulting mixed solution through a filter having a pore size of 0.2 μm or less.

[0084] <Resist Underlayer Film> The resist underlayer film is a resist underlayer film for electron beam or extreme ultraviolet lithography formed by the resist underlayer film forming composition. The resist underlayer film can be used in electron beam or extreme ultraviolet lithography to form a fine resist pattern on the resist underlayer film. The resist underlayer film can be easily removed by a removal solution containing an acid, etc. The resist underlayer film can be formed by coating the resist underlayer film forming composition and heating the coating film, as described below.

[0085] <Method of manufacturing semiconductor substrate> The method for producing a semiconductor substrate includes a step of directly or indirectly applying a resist underlayer film-forming composition to a substrate (hereinafter also referred to as a "resist underlayer film-forming composition application step"); a step of heating the application film formed by the resist underlayer film-forming composition application step (hereinafter also referred to as a "heating step"); a step of directly or indirectly applying a resist film-forming composition to the resist underlayer film formed by the heating step (hereinafter also referred to as a "resist film-forming composition application step"); a step of exposing the resist film formed by the resist film-forming composition application step to an electron beam or extreme ultraviolet light (hereinafter also referred to as an "exposure step"); and a step of developing the exposed resist film (hereinafter also referred to as a "development step"). In the method for producing a semiconductor substrate, the resist underlayer film-forming composition described above is used as the resist underlayer film-forming composition.

[0086] The method for producing a semiconductor substrate may further include, as necessary, a step of forming an organic underlayer film directly or indirectly on the substrate before the resist underlayer film-forming composition application step (hereinafter also referred to as an "organic underlayer film formation step").

[0087] The method for producing a semiconductor substrate may further include, as necessary, a step of removing the resist underlayer film (silicon-containing film) with a remover containing an acid (hereinafter also referred to as a "removal step").

[0088] The method for manufacturing a semiconductor substrate may further include a step of performing etching using the formed resist pattern or the like as a mask after the developing step (hereinafter, also referred to as an "etching step"). By this etching step, a fine pattern is formed on the substrate itself.

[0089] According to the method for producing a semiconductor substrate, the resist underlayer film forming composition described above is used to form a resist underlayer film, and exposure is performed with electron beams or extreme ultraviolet rays, so that a fine resist pattern can be formed on the resist underlayer film. In addition, the resist underlayer film formed has excellent removability and can be removed with a removal solution containing an acid. Therefore, according to the method for producing a semiconductor substrate, a semiconductor substrate having a fine pattern formed thereon can be efficiently produced. Note that the "semiconductor substrate" in this production method refers to a substrate used in a semiconductor device (semiconductor element), and is not limited to a substrate made of a semiconductor material.

[0090] The size of the resist pattern and substrate pattern (pattern formed on the substrate) formed in the manufacturing method preferably has a portion with a line width of, for example, 100 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, or 15 nm or less. The minimum line width of the formed resist pattern may be, for example, 2 nm, 5 nm, or 10 nm.

[0091] Each step of the method for manufacturing a semiconductor substrate will be described below.

[0092] [Resist underlayer film forming composition coating process] In this step, the resist underlayer film-forming composition is directly or indirectly coated onto a substrate. By this step, a coating film of the resist underlayer film-forming composition is formed directly or indirectly onto a substrate. In this step, the resist underlayer film-forming composition described above is used as the resist underlayer film-forming composition.

[0093] Examples of the substrate include insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, resin substrates, etc. The substrate may also be a substrate patterned with wiring grooves (trench), plug grooves (vias), etc.

[0094] The method for applying the resist underlayer film-forming composition is not particularly limited, and examples thereof include a rotational coating method.

[0095] Examples of the case where the resist underlayer film-forming composition is indirectly applied to the substrate include the case where the resist underlayer film-forming composition is applied onto another film formed on the substrate, etc. Examples of the other film formed on the substrate include an organic underlayer film formed by an organic underlayer film-forming step described below, an anti-reflection film, a low dielectric insulating film, etc.

[0096] [Heating process] In this step, the coating film formed in the resist underlayer film-forming composition coating step is heated. This heating causes the coating film to harden, forming a resist underlayer film. In addition, this heating generates amino groups from the groups represented by the above formula (2) in the compound [A], as described above, so that a resist underlayer film having amino groups on its surface is obtained.

[0097] The atmosphere in which the coating film is heated is not particularly limited, and may be, for example, air or nitrogen. Usually, the coating film is heated in air. The heating temperature, heating time, and other conditions for heating the coating film can be appropriately determined. The lower limit of the heating temperature may be, for example, 150°C, but is preferably 200°C, and more preferably 210°C or 220°C. By setting the heating temperature to the above lower limit or higher, amino groups can be sufficiently generated. The upper limit of the heating temperature is preferably 550°C, more preferably 450°C, and even more preferably 300°C. The lower limit of the heating time is preferably 15 seconds, and more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and more preferably 600 seconds.

[0098] When the resist underlayer film forming composition contains an acid generator, and the acid generator is an acid generator that generates an acid upon exposure to light, the formation of the resist underlayer film can be promoted by combining heating with exposure to light. Also, when the acid generator is an acid generator that generates an acid upon heating, the acid is generated by the above-mentioned heating, and the curing reaction can be promoted.

[0099] The lower limit of the average thickness of the resist underlayer film formed by this process is preferably 1 nm, more preferably 3 nm, and even more preferably 5 nm. The upper limit of the average thickness is preferably 300 nm, more preferably 100 nm, more preferably 50 nm, and even more preferably 20 nm. The average thickness of the resist underlayer film is a value measured using a spectroscopic ellipsometer (JAWOOLLAM's "M2000D").

[0100] [Resist film-forming composition application process] In this step, a resist film forming composition is applied directly or indirectly to the resist underlayer film formed in the heating step, and a resist film is formed directly or indirectly on the resist underlayer film by this step.

[0101] The method for applying the resist film-forming composition is not particularly limited, and examples thereof include a rotational coating method.

[0102] To explain this process in more detail, for example, a resist composition is applied so that the resist film to be formed has a predetermined thickness, and then the resist film is formed by volatilizing the solvent in the applied film through pre-baking (hereinafter also referred to as "PB").

[0103] The PB temperature and PB time can be appropriately determined depending on the type of resist film-forming composition used, etc. The lower limit of the PB temperature is preferably 30°C, more preferably 50°C. The upper limit of the PB temperature is preferably 200°C, more preferably 150°C. The lower limit of the PB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the PB time is preferably 600 seconds, more preferably 300 seconds.

[0104] The resist film-forming composition used in this step is not particularly limited, and a known resist film-forming composition can be used. Usually, the resist film-forming composition contains an acid generator (radiation-sensitive acid generator) that generates an acid upon exposure to electron beams or extreme ultraviolet rays. Examples of the resist film-forming composition include negative or positive resist film-forming compositions that contain a resin and the acid generator. The resin is preferably alkali-soluble. The resin also preferably has an acid-dissociable group.

[0105] [Exposure process] In this process, the resist film formed by the resist film-forming composition application process is exposed to electron beams or extreme ultraviolet rays (wavelength 13.5 nm, etc., also referred to as "EUV"). Specifically, the resist film is irradiated with electron beams or extreme ultraviolet rays, for example, through a mask having a predetermined pattern. This process causes a difference in solubility in a developer between exposed and unexposed areas of the resist film. The exposure conditions can be appropriately determined depending on the type of resist film-forming composition used, etc.

[0106] In this process, after the exposure, post-exposure baking (hereinafter also referred to as "PEB") can be performed to improve the performance of the resist film, such as resolution, pattern profile, and developability. The PEB temperature and PEB time can be appropriately determined depending on the type of resist film-forming composition used, etc. The lower limit of the PEB temperature is preferably 50°C, more preferably 70°C. The upper limit of the PEB temperature is preferably 200°C, more preferably 150°C. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the PEB time is preferably 600 seconds, more preferably 300 seconds.

[0107] [Development process] In this process, the exposed resist film is developed. Examples of the developer used in this development include an alkaline aqueous solution (alkaline developer) and an organic solvent-containing solution (organic solvent developer). For example, in the case of a positive type using an alkaline developer, the solubility of the exposed part of the resist film in an alkaline aqueous solution is increased, so that the exposed part is removed by performing alkaline development to form a positive resist pattern. In the case of a negative type using an organic solvent developer, the solubility of the exposed part of the resist film in an organic solvent is decreased, so that the non-exposed part, which has a relatively high solubility in an organic solvent, is removed by performing organic solvent development to form a negative resist pattern.

[0108] Examples of the alkaline aqueous solution (alkaline developer) include alkaline aqueous solutions in which at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved.

[0109] The lower limit of the content of the alkaline compound in the alkaline aqueous solution is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass, and the upper limit of the content is preferably 20% by mass, more preferably 10% by mass, and even more preferably 5% by mass.

[0110] As the alkaline aqueous solution, a TMAH aqueous solution is preferable, and a 2.38 mass % TMAH aqueous solution is more preferable.

[0111] The organic solvent contained in the organic solvent-containing liquid (organic solvent developer) may be any known organic solvent used in organic solvent development, such as the same as those exemplified as the solvent [B] in the resist film-forming composition.

[0112] The organic solvent is preferably an ester-based solvent, an ether-based solvent, an alcohol-based solvent, a ketone-based solvent and / or a hydrocarbon-based solvent, and more preferably an ester-based solvent.

[0113] The lower limit of the content of the organic solvent in the organic solvent-containing liquid is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass.

[0114] These developers may be used alone or in combination of two or more. After development, the film is generally washed and dried.

[0115] [Organic lower layer film formation process] In this step, an organic underlayer film is formed directly or indirectly on the substrate before the resist underlayer film-forming composition coating step. This step is an optional step. By this step, an organic underlayer film is formed directly or indirectly on the substrate. Note that "before the resist underlayer film-forming composition coating step" does not mean just before the resist underlayer film-forming composition coating step, but means a point upstream of the resist underlayer film-forming composition coating step. Therefore, any other optional step may be provided between this step and the resist underlayer film-forming composition coating step.

[0116] The organic underlayer film can be formed by coating an organic underlayer film-forming composition. Examples of methods for forming an organic underlayer film by coating an organic underlayer film-forming composition include a method in which the organic underlayer film-forming composition is directly or indirectly coated on a substrate, and the coated film is heated or exposed to light to cure the film. Examples of the organic underlayer film-forming composition include "HM8006" by JSR Corporation. Heating and exposure conditions can be appropriately determined depending on the type of organic underlayer film-forming composition used.

[0117] An example of a case where an organic underlayer film is formed indirectly on a substrate is a case where an organic underlayer film is formed on a low dielectric insulating film formed on a substrate.

[0118] [Removal process] In this step, the resist underlayer film is removed with a removal solution containing an acid. This step is an optional step. The resist underlayer film is removed from the substrate by this step. This step is not limited to being performed immediately after the resist underlayer film is formed, and may be performed at any time after the resist underlayer film is formed.

[0119] When this process is carried out before the resist film-forming composition application process, for example, when defects or the like are detected in the resist underlayer film before the resist film-forming composition application process, the resist underlayer film can be easily removed as a rework process.

[0120] In addition, when this step is performed after the etching step, the resist underlayer film residue after etching can be removed. In this manufacturing method, there is also an advantage that the remaining resist film can be removed at the same time.

[0121] Examples of the acid-containing removal liquid include a liquid containing acid and water, a liquid obtained by mixing acid, hydrogen peroxide, and water, etc. Examples of the acid include sulfuric acid, hydrofluoric acid, hydrochloric acid, etc. More specifically, examples of the acid-containing removal liquid include a liquid obtained by mixing hydrofluoric acid and water, a liquid obtained by mixing sulfuric acid, hydrogen peroxide, and water, a liquid obtained by mixing hydrochloric acid, hydrogen peroxide, and water, etc.

[0122] The method for removing the resist underlayer film is not particularly limited as long as it is a method that can bring the resist underlayer film into contact with the removal liquid, and examples thereof include a method of immersing a substrate in the removal liquid, a method of spraying the removal liquid, and a method of applying the removal liquid.

[0123] The conditions such as temperature and time when removing the resist underlayer film are not particularly limited, and can be appropriately determined depending on the film thickness of the resist underlayer film, the type of removal solution used, etc. The lower limit of the temperature of the removal solution is preferably 20°C, more preferably 40°C. The upper limit of the temperature is preferably 100°C, more preferably 80°C. The lower limit of the time is preferably 1 minute, more preferably 3 minutes, and in some cases more preferably 5 minutes or 10 minutes. The upper limit of the time is preferably 20 minutes, more preferably 10 minutes, and even more preferably 5 minutes.

[0124] In this step, after removing the resist underlayer film, washing and / or drying may be carried out.

[0125] [Etching process] This process is a process of performing etching using a resist pattern or the like as a mask. The number of times of etching may be one or more times, that is, etching may be performed sequentially using the pattern obtained by etching as a mask, but from the viewpoint of obtaining a pattern with a better shape, multiple times is preferable. When performing multiple etchings, for example, when the organic underlayer film is not present, etching is performed sequentially in the order of the resist underlayer film and the substrate, and when the organic underlayer film is present, etching is performed sequentially in the order of the resist underlayer film, the organic underlayer film, and the substrate. Examples of the etching method include dry etching and wet etching. Among these, dry etching is preferable from the viewpoint of improving the shape of the pattern of the substrate. As the etching gas, fluorine-based gas, oxygen-based gas, etc. are appropriately selected according to the material of the mask and the layer to be etched. For example, fluorine-based gas is usually used for dry etching of the resist underlayer film (silicon-containing film) using the resist pattern as a mask, and a mixture of oxygen-based gas and inert gas is preferably used. Oxygen-based gas is usually used for dry etching of the organic underlayer film using the resist underlayer film (silicon-containing film) pattern as a mask. For dry etching of the substrate using the organic underlayer film pattern as a mask, the same gases and the like as those for dry etching of the resist underlayer film (silicon-containing film) are used. After the above etching, a patterned substrate having a predetermined pattern is obtained. EXAMPLES

[0126] The following examples are provided to illustrate the present invention and are not intended to limit the scope of the present invention.

[0127] In the present examples, the weight average molecular weight (Mw) of the compound [A], the concentration of the compound [A] in solution, and the average thickness of the film were measured by the following methods.

[0128] [Measurement of weight average molecular weight (Mw)] The weight-average molecular weight (Mw) of the compound [A] was measured by gel permeation chromatography (GPC) using GPC columns (two "G2000HXL", one "G3000HXL" and one "G4000HXL" columns) manufactured by Tosoh Corporation under the following conditions. Eluent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0129] [[A] Concentration of compound in solution] 0.5 g of the solution of compound [A] was baked at 250°C for 30 minutes, and the mass of the residue obtained was measured. The mass of this residue was divided by the mass of the solution of compound [A] to calculate the concentration of the solution of compound [A] (unit: mass%).

[0130] [Average film thickness] The average thickness of the film was measured using a spectroscopic ellipsometer (JAWOOLLAM's "M2000D").

[0131] <Synthesis of [A] compound, etc.> In the following synthesis examples, unless otherwise specified, parts by mass refer to a value when the total mass of the monomers used is taken as 100 parts by mass. The monomers (hereinafter also referred to as "monomers (M-1) to (M-23)") used in the synthesis of the compound [A] etc. are shown below.

[0132] [ka]

[0133] [Synthesis Example 1] Synthesis of compound (A-1) In a reaction vessel, the above compounds (M-1), (M-4) and (M-5) (total 100 parts by mass) were dissolved in 91 parts by mass of propylene glycol monoethyl ether so that the molar ratio was 83 / 12 / 5 (mol%) to prepare a monomer solution. The temperature inside the reaction vessel was set to 5°C, and 46 parts by mass of a 9.1% by mass aqueous oxalic acid solution was added dropwise over 20 minutes while stirring. After completion of the dropwise addition, the reaction vessel was heated to 40°C, and the reaction was carried out for 4 hours. After completion of the reaction, 91 parts by mass of water was added, and stirring was carried out for 1 hour. After completion of the stirring, the reaction vessel was cooled to 30°C or lower. 447 parts by mass of propylene glycol monoethyl ether was added to the cooled reaction solution, and then an evaporator was used to remove water, alcohols produced by the reaction, and excess propylene glycol monoethyl ether to obtain a propylene glycol monoethyl ether solution of compound (A-1). The Mw of compound (A-1) was 1,600. The concentration of the compound (A-1) in the propylene glycol monoethyl ether solution was 20.0% by mass.

[0134] [Synthesis Examples 2 to 22 and Comparative Synthesis Examples 1 to 2] (Synthesis of Compounds (A-2) to (A-22) and Compounds (a-1) to (a-2)) Propylene glycol monoethyl ether solutions of compounds (A-2) to (A-22) and compounds (a-1) to (a-2) were obtained in the same manner as in Synthesis Example 1, except that the type and amount (mol %) of each monomer shown in Table 1 below was used. The Mw of the obtained [A] compound and the concentration (mass %) of [A] compound in the above-mentioned propylene glycol monoethyl ether solution are also shown in Table 1. In Table 1, "-" indicates that the corresponding monomer was not used.

[0135] [Table 1]

[0136] <Preparation of Resist Underlayer Film Forming Composition> The solvent [B] and the acid generator [C] used in the preparation of the resist underlayer film-forming composition are shown below.

[0137] [[B] Solvent] B-1: Propylene glycol monomethyl ether B-2: Propylene glycol monomethyl ether acetate [[C] Acid generator C-1: A compound represented by the following formula (C-1):

[0138] [ka]

[0139] [Example 1] 0.5 parts by mass of (A-1) as the compound [A] (excluding the solvent), 94.5 parts by mass of (B-1) as the solvent [B] (including (B-1) as the solvent contained in the solution of the compound [A]), and 5.0 parts by mass of (B-2) were mixed, and the resulting solution was filtered through a PTFE (polytetrafluoroethylene) filter having a pore size of 0.2 μm to prepare a composition (resist underlayer film-forming composition) (J-1).

[0140] [Examples 2 to 24 and Comparative Examples 1 and 2] Compositions (J-2) to (J-24) and (j-1) to (j-2) were prepared in the same manner as in Example 1, except that the components were used in the types and amounts shown in Table 2 below. In Table 2, "-" indicates that the corresponding component was not used.

[0141] <Preparation of resist composition> The resist composition was prepared as follows: Resist composition (R-1) was obtained by mixing 100 parts by mass of a polymer having a structural unit (1) derived from 4-hydroxystyrene, a structural unit (2) derived from styrene, and a structural unit (3) derived from 4-t-butoxystyrene (the content ratio of each structural unit is (1) / (2) / (3)=65 / 5 / 30 (mol%)), 1.0 part by mass of triphenylsulfonium trifluoromethanesulfonate as a radiation-sensitive acid generator, and 4,400 parts by mass of ethyl lactate and 1,900 parts by mass of propylene glycol monomethyl ether acetate as a solvent, and filtering the resulting solution with a PTFE filter having a pore size of 0.45 μm.

[0142] <Evaluation> Each of the prepared compositions (resist underlayer film-forming compositions) was evaluated for resist pattern collapse suppression ability and film removability by the following methods. The evaluation results are shown in Table 2.

[0143] [Resist pattern collapse prevention] On a 12-inch silicon wafer, an organic underlayer film forming material ("HM8006" by JSR Corporation) was applied by a spin coating method using a spin coater ("CLEAN TRACK ACT12" by Tokyo Electron Co., Ltd.), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. On this organic underlayer film, the composition (resist underlayer film forming composition) prepared above was applied, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist underlayer film with an average thickness of 10 nm. On the resist underlayer film formed above, a resist composition (R-1) was applied, heated at 130°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. Next, the resist film was irradiated with extreme ultraviolet rays by changing the exposure dose using an EUV scanner (ASML's "TWINSCAN NXE:3300B" (NA 0.3, sigma 0.9, quadrupole illumination, 1:1 line and space mask with a line width of 25 nm on the wafer). After irradiation with extreme ultraviolet rays, the substrate was heated at 110°C for 60 seconds, and then cooled at 23°C for 60 seconds. Then, development was performed by the paddle method using a 2.38 mass% TMAH aqueous solution (20 to 25°C). Then, the substrate was washed with water and dried to obtain an evaluation substrate on which a resist pattern was formed. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-6300") was used to measure and observe the resist pattern of the evaluation substrate. Resist pattern collapse suppression: If no collapse of the resist pattern of the 13 nm line width was observed, the result was "A" (very good). If collapse of the resist pattern of the 13 nm line width was confirmed, but collapse of the resist pattern of the 18 nm line width was not confirmed, the rating was "B" (better). If collapse of the resist pattern of the 18 nm line width was confirmed but collapse of the resist pattern of the 22 nm line width was not confirmed, the result was "C" (good). If collapse of the resist pattern of a line with a line width of 24 nm is confirmed, it is rated as "D" (failure). It was rated as follows:

[0144] [Membrane removability] The composition (resist underlayer film forming composition) prepared above was applied onto a 12-inch silicon wafer, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a film (resist underlayer film) with an average thickness of 10 nm. The obtained film-attached substrate was immersed in a removal solution (a mixed aqueous solution of 96% by mass sulfuric acid / 30% by mass hydrogen peroxide = 3 / 1 (volume ratio)) heated to 50°C for 5 minutes, washed with water, and dried to obtain a substrate for evaluation. Each of the film-attached substrates obtained above was immersed in a removal solution (a mixed aqueous solution of 96% by mass sulfuric acid / 30% by mass hydrogen peroxide = 3 / 1 (volume ratio)) heated to 50°C for 10 minutes, washed with water, and dried to obtain a substrate for evaluation. The cross section of each of the evaluation substrates obtained above was observed using a field emission scanning electron microscope ("SU8220" manufactured by Hitachi High-Technologies Corporation). If no resist undercoat film remains after immersion in the remover for 5 minutes, the rating is "A" (good). If the resist underlayer film remains after immersion in the remover for 5 minutes, but the silicon-containing film does not remain after immersion in the remover for 10 minutes, the sample is rated as "B" (fairly good). If the resist underlayer film remains after immersion in the removal solution for 5 and 10 minutes, it is rated as "C" (Fail). It was rated as follows:

[0145] [Table 2]

[0146] As is clear from the results in Table 2 above, each composition of the examples (resist underlayer film-forming composition) had good resist pattern collapse suppression properties, and a fine resist pattern could be formed on the resist underlayer film. Furthermore, the resist underlayer film formed from each composition of the examples had good film removability. [Industrial Applicability]

[0147] The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography of the present invention can be suitably used in the production of semiconductor substrates, etc.

Claims

1. A polysiloxane compound having a first structural unit represented by the following formula (1): Solvent and A resist underlayer film forming composition for electron beam or extreme ultraviolet lithography, comprising: 【Chemistry 1】 In formula (1), X is a group represented by the following formula (2). a is an integer of 1 to 3. When a is 2 or more, multiple Xs are the same or different. R １ is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R １ are the same or different, provided that a+b is 3 or less. 【Chemistry 2】 (In formula (2), R ２ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, multiple R ２ are the same or different. ３ is a monovalent organic group having 1 to 20 carbon atoms. L is a single bond or a divalent linking group. * indicates the bonding site with the silicon atom in the above formula (1).

2. R in the above formula (2) ２ The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to claim 1, wherein is a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

3. R in the above formula (2) ２ 3. The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to claim 2, wherein the chain hydrocarbon group represented by the following formula is bonded to an oxygen atom via a tertiary carbon atom.

4. 4. The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to claim 1, wherein n in the above formula (2) is 1.

5. R in the above formula (2) ３ The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to any one of claims 1 to 4, wherein the organic group represented by the formula (I) is a monovalent hydrocarbon group having 1 to 20 carbon atoms.

6. The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to any one of claims 1 to 5, wherein the linking group represented by L in the formula (2) is a divalent chain hydrocarbon group having 1 to 20 carbon atoms.

7. The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to claim 1 , wherein the polysiloxane compound further has a second structural unit represented by the following formula (3): 【Chemistry 3】 (In formula (3), R ４ is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. c is an integer of 1 to 3. When c is 2 or more, multiple R ４ are the same or different.)

8. The resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to claim 1 , wherein the polysiloxane compound further has a third structural unit represented by the following formula (4): 【Chemistry 4】

9. A resist underlayer film for electron beam or extreme ultraviolet lithography, formed from the resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to any one of claims 1 to 8.

10. A step of directly or indirectly applying a resist underlayer film forming composition for electron beam or extreme ultraviolet lithography according to any one of claims 1 to 8 to a substrate; a step of heating the coating film formed by the resist underlayer film-forming composition coating step; a step of directly or indirectly applying a resist film-forming composition to the resist underlayer film formed by the heating step; a step of exposing the resist film formed by the resist film-forming composition coating step to an electron beam or extreme ultraviolet light; developing the exposed resist film; A method for manufacturing a semiconductor substrate comprising the steps of:

11. The method for manufacturing a semiconductor substrate according to claim 10, wherein the heating step is performed at a heating temperature of 200° C. or higher.

12. Prior to the resist underlayer film-forming composition coating step, A step of forming an organic underlayer film directly or indirectly on the substrate. The method for manufacturing a semiconductor substrate according to claim 10 or 11, further comprising:

13. A step of removing the resist underlayer film with a removal solution containing an acid. The method for manufacturing a semiconductor substrate according to claim 10, 11 or 12, further comprising:

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