Underlayer film material for self-assembled materials

Abstract

Disclosed is a composition for forming an underlayer film for the formation of an underlayer film of a self-assembled film, the composition containing a polymer which has a unit structure (A) that has an alicyclic hydrocarbon group having a reactive group.

Description

Underlayer materials for self-organizing materials

[0001] The present invention relates to a composition for forming an underlayer film used to form an underlayer film of a self-assembled film, an underlayer film, and a method for manufacturing a semiconductor device using the composition and the underlayer film.

[0002]

[0003] In recent years, with the further miniaturization of large-scale integrated circuits (LSIs), there has been a demand for techniques for processing ever more delicate structures. In response to this demand, attempts have been made to form ever finer patterns by utilizing phase-separated structures formed by the self-assembly of block copolymers, in which mutually incompatible polymers are bonded. For example, a pattern formation method has been proposed, in which an underlayer film-forming composition is applied to a substrate to form an underlayer film made of the composition, a self-assembled film containing a block copolymer in which two or more polymers are bonded is formed on the surface of the underlayer film, the block copolymer in the self-assembled film is phase-separated, and at least one polymer phase of the polymers constituting the block copolymer is selectively removed.

[0003] Patent Document 1 discloses a composition for forming an underlayer film of a self-assembled film, which contains a polymer having 20 mol % or more unit structures of an aromatic vinyl compound, such as optionally substituted styrene, vinylnaphthalene, acenaphthylene, or vinylcarbazole, per total unit structures of the polymer, and having 1 mol % or more unit structures of a polycyclic aromatic vinyl compound per total unit structures of the aromatic vinyl compound.

[0004] International Publication No. 2014 / 097993

[0005] As the underlayer film of the self-assembled film, a base film that can be more easily oriented in a desired vertical pattern (that can form vertical orientation in the self-assembled film) is required to enable the formation of fine patterns using the self-assembled film.

[0006] The present invention provides a composition for forming an underlayer film that has good film-forming properties as an underlayer film for a self-assembled film and that can form an underlayer that can form a vertical alignment in the self-assembled film. The present invention also provides an underlayer film using the composition for forming an underlayer film, and a method for manufacturing a semiconductor device using the underlayer film.

[0007] The present inventors conducted extensive research to solve the above-mentioned problems, and as a result, found that the above-mentioned problems can be solved, and completed the present invention having the following gist. That is, the present invention includes the following: [1] A composition for forming an underlayer film for forming an underlayer film of a self-assembled monolayer, comprising a polymer, the polymer having a unit structure (A) having an alicyclic hydrocarbon group having a reactive group. [2] The composition for forming an underlayer film according to [1], wherein the unit structure (A) is a unit structure represented by the following formula (A-1): (In formula (A-1), R １ represents a hydrogen atom or a methyl group. １ represents a single bond, an ester group, or an amide group. １ represents a single bond or an alkylene group having 1 to 6 carbon atoms. Cy represents an alicyclic hydrocarbon group having a reactive group. [3] The composition for forming an underlayer film according to [1] or [2], wherein the polymer further has a unit structure represented by the following formula (B-1): (In formula (B-1), R １１ represents a hydrogen atom or a methyl group. １１ represents an aromatic group which may be substituted. １１ represents optionally substituted naphthalene, anthracene, phenanthrene, pyrene, triphenylene, chrysene, naphthacene, biphenylene, fluorene, or carbazole, or benzene having one or more hydrocarbon groups having 1 to 6 carbon atoms as substituents. [5] The composition for forming an underlayer film according to any one of [1] to [4], wherein the polymer further has a unit structure (C) having a monocyclic aromatic structure. [6] The composition for forming an underlayer film according to [5], wherein the unit structure (C) is a unit structure represented by the following formula (C-1): (In formula (C-1), R ２１ represents a hydrogen atom or a methyl group. ２１ represents an ester group or an amide group. ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. ２１ represents a single bond or an ether group.２１ represents optionally substituted benzene, naphthalene or anthracene. ２２ represents a halogen atom or an organic group having 1 to 10 carbon atoms which may be substituted. n represents an integer of 0 to 5. R ２２ When there are two or more, there are two or more R ２２ may be the same or different.) [7] The composition for forming an underlayer film according to any one of [1] to [6], wherein the polymer further has a unit structure (D) having a hydrocarbon group (excluding an alicyclic hydrocarbon group) having a reactive group. [8] The composition for forming an underlayer film according to [7], wherein the unit structure (D) is a unit structure represented by the following formula (D-1): (In formula (D-1), R ３１ represents a hydrogen atom or a methyl group. ３１ represents an ester group or an amide group. ３２represents a hydrocarbon group having 1 to 12 carbon atoms and having a reactive group (excluding alicyclic hydrocarbon groups). [9] The composition for forming an underlayer film according to any one of [1] to [8], wherein the molar ratio of the unit structure (A) to all unit structures of the polymer is less than 60 mol %.

[10] The composition for forming an underlayer film according to any one of [3] to [9], wherein the molar ratio of the unit structure (B-1) to all unit structures of the polymer is 45 mol % to 80 mol %.

[11] The composition for forming an underlayer film according to any one of [1] to

[10] , further comprising a crosslinking agent, the content of which is 20 mass % to 50 mass % of the polymer.

[12] The composition for forming an underlayer film according to any one of [1] to

[11] , wherein the self-assembled film is a film containing a block copolymer.

[13] The composition for forming an underlayer film according to any one of [1] to

[13] , which is a composition for forming an underlayer film that is used as an underlayer film for a resist film, either a photoresist film or an electron beam resist film, in lithography using the self-assembled film and the resist film, and is then used as an underlayer film for the self-assembled film.

[14] An underlayer film that is a fired product of a coating film of the composition for forming an underlayer film according to any one of [1] to

[13] .

[15] The underlayer film according to

[14] , wherein the underlayer film has a thickness of less than 10 nm.

[16] A method for manufacturing a semiconductor device, comprising: forming an underlayer film on a semiconductor substrate using the composition for forming an underlayer film according to any one of [1] to

[13] ; and forming a self-assembled film on the underlayer film.

[17] The method for manufacturing a semiconductor element according to

[16] , wherein in the step of forming a self-assembled film, the self-assembled film is formed on the patterned underlayer film, and further comprising the steps of: forming a resist film, which is either a photoresist film or an electron beam resist film, on the underlayer film; irradiating the resist film with light or an electron beam and then developing the resist film to obtain a resist pattern; and etching the underlayer film using the resist pattern as a mask to form the patterned underlayer film.

[18] The method for manufacturing a semiconductor element according to

[17] , further comprising a step of forming a brush layer in gaps in the pattern of the patterned underlayer film between the step of forming the patterned underlayer film and the step of forming the self-assembled film.

[19] The method for manufacturing a semiconductor element according to any one of

[16] to

[18] , wherein the self-assembled film is a film containing a block copolymer.

[20] The method for manufacturing a semiconductor element according to any one of

[17] to

[19] , further comprising a step of removing the resist pattern after the step of forming the patterned underlayer film.

[0008] According to the present invention, it is possible to provide a composition for forming an underlayer film that has good film-forming properties as an underlayer film of a self-assembled film and that enables the formation of a self-assembled film with good vertical alignment. The present invention also provides an underlayer film using the composition for forming an underlayer film, and a method for manufacturing a semiconductor device using the underlayer film.

[0009] FIG. 1A is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 1). FIG. 1B is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 2). FIG. 1C is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 3). FIG. 1D is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 4). FIG. 1E is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 5). FIG. 1F is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 6). FIG. 1G is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 7). FIG. 1H is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 8). FIG. 1I is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor element of the present invention (part 9). FIG. 2 is an electron microscope (SEM) photograph of a microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 1. Figure 3 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 2. Figure 4 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 3. Figure 5 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 4. Figure 6 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 5. Figure 7 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 6. Figure 8 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Example 7. FIG. 9 is an electron microscope (SEM) photograph of the microphase-separated structure of a self-assembled film formed on an underlayer film formed from the underlayer film-forming composition of Comparative Example 1.

[0010] (Underlayer film-forming composition) The underlayer film-forming composition of the present invention is a composition for forming an underlayer film of a self-assembled film. The underlayer film-forming composition contains a polymer. The polymer has a unit structure (A) having an alicyclic hydrocarbon group having a reactive group.

[0011] The composition for forming an underlayer film contains a polymer, and the polymer has a unit structure (A) having an alicyclic hydrocarbon group having a reactive group, so that an underlayer film that can form a vertical arrangement in the self-assembled film can be formed as the underlayer film of the self-assembled film.

[0012] <Polymer> The polymer has a unit structure (A) having an alicyclic hydrocarbon group having a reactive group. Hereinafter, this polymer may be referred to as a "specific polymer."

[0013] <<Unit Structure (A)>> The unit structure (A) is a unit structure having an alicyclic hydrocarbon group having a reactive group. Examples of the alicyclic hydrocarbon group in the unit structure (A) include a cyclohexyl group, an isobornyl group, a dicyclopentanyl group, an adamantyl group, a cyclopropyl group, a cyclobutyl group, and a cyclopentyl group, with a cyclohexyl group, an isobornyl group, a dicyclopentanyl group, and an adamantyl group being preferred. The alicyclic hydrocarbon group may also have a substituent other than the reactive group. The alicyclic hydrocarbon group preferably has 7 to 14 carbon atoms, and more preferably 8 to 12 carbon atoms.

[0014] Examples of reactive groups contained in the unit structure (A) include a hydroxy group, an epoxy group, an acyl group, an acetyl group, a formyl group, a benzoyl group, a carboxy group, a carbonyl group, an amino group, an imino group, a cyano group, an azo group, an azido group, a thiol group, a sulfo group, and an allyl group. Among these reactive groups, a hydroxy group is preferred. One or more reactive groups may be contained per alicyclic hydrocarbon group, and it is preferred that one reactive group be contained per alicyclic hydrocarbon group.

[0015] The unit structure (A) is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, a unit structure represented by the following formula (A-1) is preferred.

[0016] (In formula (A-1), R １ represents a hydrogen atom or a methyl group. １ represents a single bond, an ester group, or an amide group. １ represents a single bond or an alkylene group having 1 to 6 carbon atoms. Cy represents an alicyclic hydrocarbon group having a reactive group.

[0017] In formula (A-1), Y １ represents a single bond or a divalent alkylene group having 1 to 6 carbon atoms. Examples of the divalent alkylene group having 1 to 6 carbon atoms include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group, a pentylene group, and a hexylene group. In formula (A-1), X １ is an ester group, Y １ is preferably a single bond.

[0018] Cy represents an alicyclic hydrocarbon group having a reactive group, wherein the reactive group in Cy is preferably a hydroxy group, and the alicyclic hydrocarbon group is preferably an adamantyl group.

[0019] Examples of the unit structure represented by formula (A-1) include the following:

[0020]

[0021] The unit structure (A) in the polymer may be of one or more types, preferably one or two types.

[0022] <<Unit Structure (B)>> The polymer of the present invention may have a unit structure other than the unit structure (A). From the viewpoint of suitably obtaining the effects of the present invention, such a unit structure may be a unit structure represented by the following formula (B-1):

[0023] (In formula (B-1), R １１ represents a hydrogen atom or a methyl group. １１ represents an aromatic group which may be substituted.

[0024] In formula (B-1), Ar １１Examples of Ar include optionally substituted naphthalene, anthracene, phenanthrene, pyrene, triphenylene, chrysene, naphthacene, biphenylene, fluorene, and carbazole. １１ Examples of the substituent that Ar may have include a halogen atom, a hydroxy group, an alkyl group, an alkoxy group, a thiol group, a cyano group, a carboxy group, an amino group, an amide group, an alkoxycarbonyl group, and a thioalkyl group. １１ may be benzene having one or more hydrocarbon groups having 1 to 6 carbon atoms as substituents. １１ The hydrocarbon group in Ar may be linear, branched, or cyclic, and is preferably branched. １１ The hydrocarbon group in Ar is more preferably a t-butyl group. １１ The hydrocarbon group in formula (B-1) may be one or more. １１ The number of carbon atoms is preferably 6 to 20, and more preferably 6 to 14.

[0025] Examples of the unit structure represented by formula (B-1) include the following:

[0026]

[0027]

[0028]

[0029] The unit structure (B-1) in the polymer may be of one or more types, preferably one or two types.

[0030] <<Unit Structure (C)>> The polymer may have a unit structure other than the unit structure (A) and the unit structure (B). From the viewpoint of suitably achieving the effects of the present invention, an example of such a unit structure is the unit structure (C) having a monocyclic aromatic structure. The unit structure (C) is a unit structure different from the unit structures (A) and (B). For example, the unit structure (C) does not have an alicyclic hydrocarbon group having a reactive group, which the unit structure (A) has. Furthermore, the unit structure (C) does not have a benzene having, as a substituent, one or more hydrocarbon groups having 1 to 6 carbon atoms, which the unit structure (B) has.

[0031] The unit structure (C) is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, a unit structure represented by the following formula (C-1) is preferred.

[0032] (In formula (C-1), R ２１ represents a hydrogen atom or a methyl group. ２１ represents an ester group or an amide group. ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. ２１ represents a single bond or an ether group. ２１ represents optionally substituted benzene, naphthalene or anthracene. ２２ represents a halogen atom or an organic group having 1 to 10 carbon atoms which may be substituted. n represents an integer of 0 to 5. R ２２ When there are two or more, there are two or more R ２２ may be the same or different.)

[0033] X ２１ is preferably an ester group. ２２ The optionally substituted organic group having 1 to 10 carbon atoms in the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or an acyl group having 2 to 10 carbon atoms which may be substituted with a halogen atom. An example of an acyl group having 2 to 10 carbon atoms which may be substituted with a halogen atom is a benzoyl group. Usually, Y ２１When is a single bond, Z ２１ represents a single bond.

[0034] The unit structure represented by formula (C-1) preferably has 9 to 19 carbon atoms.

[0035] Examples of the unit structure represented by formula (C-1) include the following:

[0036]

[0037] The vinyl polymer may contain one or more types of unit structure (C), preferably one or two types.

[0038] <<Unit Structure (D)>> The polymer may have a unit structure other than the unit structure (A), the unit structure (B), and the unit structure (C). From the viewpoint of suitably achieving the effects of the present invention, such a unit structure may include a unit structure (D) having a hydrocarbon group (excluding alicyclic hydrocarbon groups) having a reactive group. The unit structure (D) is a unit structure different from the unit structure (A), the unit structure (B), and the unit structure (C). For example, the unit structure (D) does not have an alicyclic hydrocarbon group having a reactive group, which the unit structure (A) has.

[0039] The unit structure (D) is not particularly limited, but from the viewpoint of suitably achieving the effects of the present invention, a unit structure represented by the following formula (D-1) is preferred.

[0040] (In formula (D-1), R ３１ represents a hydrogen atom or a methyl group. ３１ represents an ester group or an amide group. ３２ represents a hydrocarbon group having 1 to 12 carbon atoms (excluding alicyclic hydrocarbon groups) having a reactive group.

[0041] Examples of the hydrocarbon group having 1 to 12 carbon atoms contained in the unit structure (D-1) include alkyl groups having 1 to 12 carbon atoms. In these alkyl groups, some of the hydrogen atoms may be substituted with a monocyclic aromatic hydrocarbon ring such as a benzene ring. Examples of the reactive group contained in the unit structure (D-1) include a hydroxy group, an epoxy group, an acyl group, an acetyl group, a formyl group, a benzoyl group, a carboxy group, a carbonyl group, an amino group, an imino group, a cyano group, an azo group, an azido group, a thiol group, a sulfo group, and an allyl group. Among these reactive groups, a hydroxy group is preferred. It is sufficient that one or two or more reactive groups are contained per hydrocarbon group, and it is preferable that one reactive group is contained per hydrocarbon group.

[0042] Examples of the unit structure represented by formula (D-1) include the following:

[0043]

[0044] The molar ratio of the unit structure (A) to all unit structures of the polymer is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, it is preferably less than 60 mol%, more preferably 50 mol% or less, and particularly preferably 45 mol% or less. The molar ratio of the unit structure (A) to all unit structures of the polymer is preferably 5 mol% or more, more preferably 10 mol% or more, and particularly preferably 15 mol% or more.

[0045] The molar ratio of the unit structure (B-1) to all unit structures of the polymer is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, it is preferably 45 mol% or more, more preferably 50 mol% or more, and particularly preferably 55 mol% or more. The molar ratio of the unit structure (B-1) to all unit structures of the vinyl polymer is preferably 80 mol% or less, more preferably 70 mol% or less, and particularly preferably 60 mol% or less.

[0046] When the polymer has the unit structure (C), the molar ratio of the unit structure (C) to all the unit structures of the polymer is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, it is preferably 5 mol% or more, more preferably 15 mol% or more, and particularly preferably 20 mol% or more. The molar ratio of the unit structure (C) to all the unit structures of the polymer is preferably 50 mol% or less, more preferably 40 mol% or less, and particularly preferably 30 mol% or less.

[0047] When the polymer has the unit structure (D), the molar ratio of the unit structure (D) to all unit structures of the polymer is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, it is preferably 5 mol% or more, more preferably 10 mol% or more, and particularly preferably 15 mol% or more. The molar ratio of the unit structure (D) to all unit structures of the polymer is preferably 50 mol% or less, more preferably 40 mol% or less, and particularly preferably 30 mol% or less.

[0048] The molar ratio of the unit structure (A) to the unit structure (B-1) in the polymer (unit structure (B-1) / unit structure (A)) is not particularly limited, but is preferably 1 to 9, and more preferably 1.5 to 5.

[0049] The distribution of the unit structures in the polymer is not particularly limited, and the polymer may be a block copolymer or a random copolymer.

[0050] The molecular weight of the polymer is not particularly limited, but the weight average molecular weight measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC) is preferably 1,500 to 100,000, and more preferably 2,000 to 50,000. The molecular weight of the polymer can be measured, for example, using a GPC apparatus (EcoSEC, HLC-8320GPC manufactured by Tosoh Corporation) and a GPC column (Shodex [registered trademark] Asahipak [registered trademark] manufactured by Showa Denko K.K.), at a column temperature of 40°C, using dimethylformamide as an eluent (elution solvent), and at a flow rate (flow rate) of 0.6 mL / min, using polystyrene (manufactured by Tosoh Corporation) as a standard sample.

[0051] <<Method for Producing Polymer>> The method for producing the specific polymer is not particularly limited, but for example, the specific polymer of the present embodiment can be obtained by reacting a carbon-carbon double bond contained in a monomer that provides unit structure (A), a carbon-carbon double bond contained in a monomer that provides any unit structure (B), a carbon-carbon double bond contained in a monomer that provides any unit structure (C), and a carbon-carbon double bond contained in a monomer that provides any unit structure (D).

[0052] As a polymerization method for the specific polymer, known polymerization methods such as radical polymerization, anionic polymerization, cationic polymerization, etc., and various known techniques such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization can be used.

[0053] The polymerization initiator used in the polymerization is not particularly limited, and examples thereof include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2 , 2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and 2,2'-azobis(2-methylpropionamidine)dihydrochloride, etc., can be used.

[0054] The solvent used during polymerization is not particularly limited, and examples thereof include dioxane, 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 monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, and butyl lactate. These may be used alone or in combination.

[0055] The reaction temperature is not particularly limited, but may be, for example, 20° C. to 150° C. The reaction time is not particularly limited, but may be, for example, 1 hour to 72 hours.

[0056] The resulting polymer-containing solution can be used as is for preparing an underlayer film-forming composition, or the polymer can be recovered and used by precipitating and isolating it in a poor solvent such as methanol, ethanol, isopropanol, or water, or a mixed solvent thereof.

[0057] The content of the specific polymer in the composition for forming an underlayer film is not particularly limited, but from the viewpoint of solubility, it is preferably 0.1% by mass to 50% by mass, and more preferably 0.1% by mass to 10% by mass, based on the entire composition for forming an underlayer film. Furthermore, the content of the specific polymer in the composition for forming an underlayer film is preferably 50% by mass to 95% by mass, more preferably 55% by mass to 90% by mass, and particularly preferably 60% by mass to 85% by mass, based on the film-constituting components. The film-constituting components refer to components other than the solvent contained in the composition.

[0058] <Crosslinking Agent> The underlayer film-forming composition preferably contains a crosslinking agent. The crosslinking agent has, for example, a functional group capable of reacting with the reactive group of the unit structure (A). The number of functional groups in the crosslinking agent is not particularly limited and may be one or two or more.

[0059] The functional group capable of reacting with the reactive group contained in the unit structure (A) is not particularly limited, and examples thereof include a hydroxy group, an epoxy group, an acyl group, an acetyl group, a formyl group, a benzoyl group, a carboxy group, a carbonyl group, an amino group, an imino group, a cyano group, an azo group, an azido group, a thiol group, a sulfo group, an allyl group, and a structure represented by the following formula (E): (In formula (E), R １０１ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxyalkyl group having 2 to 6 carbon atoms. * represents a bond.) The bond is bonded to, for example, a nitrogen atom or a carbon atom constituting an aromatic hydrocarbon ring.

[0060] When the reactive group contained in the unit structure (A) is a hydroxy group or a thiol group, examples of the functional group capable of reacting with the reactive group contained in the unit structure (A) include a structure represented by formula (E).

[0061] When the reactive group of the unit structure (A) is an epoxy group, examples of functional groups capable of reacting with the reactive group of the unit structure (A) include a carboxy group, an amino group, and a thiol group.

[0062] Examples of the crosslinking agent include compounds having two or more structures represented by the following formula (E).

[0063] R １０１ is preferably a hydrogen atom, a methyl group, an ethyl group or a group represented by the following structure. (In the structure, R １０２ represents a hydrogen atom, a methyl group, or an ethyl group. * represents a bond.

[0064] As the crosslinking agent, a melamine compound, a guanamine compound, a glycoluril compound, a urea compound, or a compound having a phenolic hydroxy group is preferred. These may be used alone or in combination of two or more.

[0065] The melamine compound is not particularly limited as long as it has a group capable of reacting with the reactive group (e.g., hydroxy group) of the unit structure (A). Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which one to six methylol groups of hexamethylol melamine are methoxymethylated, or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which one to six methylol groups of hexamethylol melamine are acyloxymethylated, or a mixture thereof.

[0066] The guanamine compound is not particularly limited as long as it has a group capable of reacting with the reactive group (e.g., hydroxy group) possessed by the unit structure (A). Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which one to four methylol groups of tetramethylolguanamine are methoxymethylated, or a mixture thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, a compound in which one to four methylol groups of tetramethylolguanamine are acyloxymethylated, or a mixture thereof.

[0067] The glycoluril compound is not particularly limited as long as it has a group capable of reacting with the reactive group (e.g., hydroxy group) of the unit structure (A). Examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound in which one to four methylol groups of tetramethylol glycoluril are methoxymethylated or a mixture thereof, and a compound in which one to four methylol groups of tetramethylol glycoluril are acyloxymethylated or a mixture thereof.

[0068] The glycoluril compound may be, for example, a glycoluril derivative represented by the following formula (1E). (In formula (1E), four R １ each independently represents a methyl group or an ethyl group, R ２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.

[0069] Examples of the glycoluril derivative represented by the formula (1E) include compounds represented by the following formulas (1E-1) to (1E-6).

[0070] The glycoluril derivative represented by formula (1E) can be obtained, for example, by reacting a glycoluril derivative represented by the following formula (2E) with at least one compound represented by the following formula (3d).

[0071] (In formula (2E), R ２ and R ３ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group; R ４ each independently represents an alkyl group having 1 to 4 carbon atoms.

[0072] (In formula (3d), R １ represents a methyl group or an ethyl group.

[0073] Examples of glycoluril derivatives represented by formula (2E) include compounds represented by formulas (2E-1) to (2E-4) below. Furthermore, examples of compounds represented by formula (3d) include compounds represented by formulas (3d-1) and (3d-2) below.

[0074] The urea compound is not particularly limited as long as it has a group capable of reacting with the reactive group (e.g., hydroxy group) of the unit structure (A). Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which one to four methylol groups of tetramethylol urea are methoxymethylated, or a mixture thereof, and tetramethoxyethyl urea.

[0075] Examples of the compound having a phenolic hydroxy group include compounds represented by the following formula (111) or (112). (In formula (111) and formula (112), Q ２ represents a single bond or a divalent organic group. ８ , R ９ , R １１ and R １２ R represents a hydrogen atom or a methyl group. ７ and R １０ n represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. ９ is 1≦n ９ an integer ≦3, n １０ is 2≦n １０ an integer ≦5, n １１ is 0≦n １１ an integer ≦3, n １２ is 0≦n １２ an integer ≦3, 3≦(n ９ +n １０ +n １１ +n １２ ) represents an integer ≦6. １３ is 1≦n １３ an integer ≦3, n １４ is 1≦n １４ an integer ≦4, n １５ is 0≦n １５ an integer ≦3, n １６ is 0≦n １６ an integer ≦3, 2≦(n １３ +n １４ +n １５ +n １６ ) represents an integer of ≦5. m2 represents an integer of 2 to 10. ２In the above, the m2-valent organic group includes, for example, an m2-valent organic group having 1 to 4 carbon atoms.

[0076] Examples of the compound represented by formula (111) or formula (112) include the following compounds. The above compound is available as a product of Asahi Organic Chemicals Co., Ltd. and Honshu Chemical Industry Co., Ltd. An example of the product is TMOM-BP, a product name of Asahi Organic Chemicals Co., Ltd.

[0077] Among these, glycoluril compounds are preferred, specifically tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, tetramethylol glycoluril compounds in which one to four methylol groups are methoxymethylated or mixtures thereof, and tetramethylol glycoluril compounds in which one to four methylol groups are acyloxymethylated or mixtures thereof, with tetramethoxymethyl glycoluril being preferred.

[0078] The molecular weight of the crosslinking agent is not particularly limited, but is preferably 1,000 or less.

[0079] The content of the crosslinking agent in the composition for forming an underlayer film is not particularly limited, but is preferably 5% by mass to 60% by mass of the specific polymer, more preferably 10% by mass to 55% by mass, and particularly preferably 20% by mass to 50% by mass.

[0080] <Curing Catalyst> The curing catalyst contained as an optional component in the underlayer film-forming composition may be either a thermal acid generator or a photoacid generator, but it is preferable to use a thermal acid generator.

[0081] Examples of the thermal acid generator include sulfonic acid compounds and carboxylic acid compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonate (pyridinium-p-toluenesulfonic acid), pyridinium phenolsulfonic 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, hydroxybenzoic acid, N-methylmorpholine-p-toluenesulfonic acid, N-methylmorpholine-p-hydroxybenzenesulfonic acid, and N-methylmorpholine-5-sulfosalicylic acid.

[0082] Examples of the photoacid generator include an onium salt compound, a sulfonimide compound, and a disulfonyldiazomethane compound.

[0083] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0084] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0085] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0086] The curing catalyst may be used alone or in combination of two or more.

[0087] When a curing catalyst is used, the content of the curing catalyst is, for example, 0.1% by mass to 50% by mass, and preferably 1% by mass to 30% by mass, relative to the crosslinking agent.

[0088] <Other Components> A surfactant may be further added to the underlayer film-forming composition in order to prevent pinholes, striations, etc., and to further improve the coating properties for preventing surface unevenness.

[0089] Examples of surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylaryl 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 monolaurate, polyoxyethylene sorbitan monopalmitate; nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; fluorine-based surfactants such as Eftop EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.), Megafac F171, F173, and R-30 (trade names, manufactured by DIC Corporation), Fluorad FC430 and FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by AGC Inc.); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of these surfactants to be added is not particularly limited, but is usually 2.0% by mass or less, and preferably 1.0% by mass or less, based on the composition for forming the underlayer film. These surfactants may be added alone or in combination of two or more.

[0090] <Solvent> The underlayer film-forming composition may contain a solvent. As the solvent, an organic solvent generally used in chemical solutions for semiconductor lithography processes is preferred. Specifically, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cyclohexane, cyclohexane-1, cyclohexane-2, cyclohexane-3, cyclohexane-4, cyclohexane-5, cyclohexane-6, cyclohexane-7, cyclohexane-8, cyclohexane-9, cyclohexane-10, cyclohexane-11, cyclohexane-12, cyclohexane-13, cyclohexane-14, cyclohexane-15, cyclohexane-16, cyclohexane-17, cyclohexane-18, cyclohexane-19, cyclohexane-20, cyclohexane-21, cyclohexane-22, cyclohexane-23, cyclohexane-24, cyclohexane-25, cyclohexane-26, cyclohexane-27, cyclohexane-28, cyclohexane-29, cyclohexane-30, cyclohexane-31, cyclohexane-32, cyclohexane-33, cyclohexane-34, cyclohexane-35, cyclohexane-36, cyclohexane-37, cyclohexane-38, cyclohexane-39, cyclohexane-40, cyclohexane-41, cyclohexane-42, cyclohexane-43, cyclohexane-44, cyclohexane-45, cyclohexane-45, cyclohexane-46, cyclohexane-47, cyclohexane-48, cyclohexane-49, cyclohexane-51, Examples of suitable solvents include heptanone, 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.

[0091] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred, and propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are particularly preferred.

[0092] The content of the solvent in the underlayer film-forming composition is not particularly limited, but is preferably 80% by mass to 99.99% by mass, more preferably 90% by mass to 99.95% by mass, and particularly preferably 95% by mass to 99.9% by mass.

[0093] (Underlayer film) The underlayer film of the present invention is a fired product of a coating film of the above-described composition for forming an underlayer film. The underlayer film of the present invention is used as an underlayer film of a self-assembled film. The underlayer film of the present invention may be used as an underlayer film of a resist film in lithography using a resist film, either a photoresist film or an electron beam resist film, and a self-assembled film, and then further used as an underlayer film of the self-assembled film.

[0094] The underlayer film of the present invention can be produced, for example, by applying a composition for forming an underlayer film onto a semiconductor substrate and baking it.

[0095] Examples of semiconductor substrates onto which the 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.

[0096] 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 a polysilicon film, a silicon oxide film, a silicon nitride film, a BPSG (Boro-Phospho Silicate Glass) film, a titanium nitride film, a titanium nitride oxide film, a tungsten film, a gallium nitride film, and a gallium arsenide film.

[0097] The semiconductor substrate may have a silicon- and organic group-containing film. The silicon- and organic group-containing film is a film formed from a hydrolysis condensation product of a hydrolyzable silane (also called an organosilicon compound) having an organic group. The silicon- and organic group-containing film contains, for example, a hydrolysis condensation product of a hydrolyzable silane containing a compound represented by the following formula (A):

[0098] (In formula (A), R ａrepresents an alkyl group, an aryl group, a halogenated alkyl group, a halogenated aryl group, an alkoxyaryl group, an alkenyl group, an organic group having an epoxy group, an organic group having an acryloyl group, an organic group having a methacryloyl group, an organic group having a mercapto group, or an organic group having a cyano group; R ｂ represents an alkoxy group, an acyloxy group, or a halogen atom, and x represents an integer of 0 to 3.

[0099] The silicon- and organic group-containing film can be formed, for example, from a silicon-containing resist underlayer film-forming composition. Examples of such a silicon-containing resist underlayer film-forming composition include the silicon-containing resist underlayer film-forming composition described below. Patent Publication No. 2020-076999, WO2019 / 181873 pamphlet, WO2019 / 082934 pamphlet, WO2019 / 009413 pamphlet, WO2018 / 181989 pamphlet, WO2018 / 079599 pamphlet, WO2016 / 080217 pamphlet, WO2016 / 009965 pamphlet, WO2016 / 009939 pamphlet, WO2015 / 194555 pamphlet, WO2014 / 098076 pamphlet, WO2014 / 069329 pamphlet, WO2014 / 046055 pamphlet, WO2013 / 191203 pamphlet, WO2013 / 115032 pamphlet, WO2013 / 022099 pamphlet, WO2012 / 102261 pamphlet, WO2012 / 053600 pamphlet, WO2012 / 039337 pamphlet, WO2011 / 105368 pamphlet, WO2011 / 102470 pamphlet, WO2011 / 033965 pamphlet, WO2010 / 140551 pamphlet, WO2010 / 071155 pamphlet, WO2010 / 021290 pamphlet, WO2009 / 104552 pamphlet, WO2009 / 088039 pamphlet, WO2009 / 069712 pamphlet

[0100] The composition for forming an underlayer film of the present invention is applied to 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. A baking temperature of 120°C to 350°C and a baking time of 0.5 to 30 minutes are preferred, and a baking temperature of 150°C to 300°C and a baking time of 0.8 to 10 minutes are more preferred.

[0101] From the viewpoint of optimally achieving the effects of the present invention, the film thickness of the underlayer film is preferably less than 10 nm, more preferably 9 nm or less, even more preferably 8 nm or less, and particularly preferably 7 nm or less. Furthermore, the film thickness of the underlayer film may be 1 nm or more, 2 nm or more, or even 3 nm or more. Generally, when the film thickness of the resist underlayer film is reduced, it becomes difficult to obtain a film with a flat surface. If the surface is not flat, it is thought that the film thickness of the resist film formed on the underlayer film will fluctuate greatly, resulting in increased roughness of the resist pattern. By containing the vinyl polymer described above, the composition for forming an underlayer film of the present invention tends to obtain an underlayer film with excellent adhesion to the substrate and excellent film formability. Therefore, it is presumed that even if the film thickness of the underlayer film is less than 10 nm, a film with a flat surface can be formed, and the roughness (LWR and CDU) of the resist pattern can be improved. The LWR (Line Width Roughness) is primarily evaluated when the resist pattern is a line and space (wiring pattern). However, when the resist pattern is a contact hole (hole pattern), the underlayer film of the present application also exhibits an effect of improving CDU (Critical Dimension Uniformity, CD uniformity) (low hole diameter variation). The CDU can be evaluated, for example, by a method similar to that described in JP 2020-003678 A (paragraph

[0386] Evaluation of In-Plane Uniformity (CDU) of Pattern Dimensions). Furthermore, when a brush layer is formed in the gaps in the pattern of the patterned underlayer film, the brush layer becomes a thin layer (for example, about 1 nm). In order to minimize the difference in thickness from the brush layer, a thin underlayer film is preferable. In this regard, the underlayer film preferably has a thickness of less than 10 nm. Furthermore, by making the thickness of the underlayer film thin, the pattern of the patterned self-assembled film can be easily transferred to the underlayer film, and in this respect, the thickness of the underlayer film is preferably less than 10 nm.

[0102] The method for measuring the thickness of the underlayer film in this specification is as follows: Measurement device name: Ellipso film thickness measurement device RE-3100 (SCREEN Corporation) SWE (single wavelength ellipsometer) mode Arithmetic mean of 8 points (for example, measuring 8 points at 1 cm intervals in the X direction of the wafer)

[0103] (Method for manufacturing a semiconductor element) One embodiment of a semiconductor element of the present invention includes steps I and II. Step I: a step of forming an underlayer film on a semiconductor substrate using the composition for forming an underlayer film of the present invention. Step II: a step of forming a self-assembled film on the underlayer film.

[0104] Another embodiment of the method for manufacturing a semiconductor device of the present invention includes steps 1 to 5. Step 1: forming an underlayer film on a semiconductor substrate using the underlayer film-forming composition of the present invention; Step 2: forming a resist film, either a photoresist film or an electron beam resist film, on the underlayer film; Step 3: irradiating the resist film with light or an electron beam, and then developing the resist film to obtain a resist pattern; Step 4: etching the underlayer film using the resist pattern as a mask to form a patterned underlayer film; Step 5: forming a self-assembled film on the patterned underlayer film.

[0105] Another embodiment of the method for manufacturing a semiconductor device of the present invention, which includes steps 1 to 5, may further include step 6. Step 6: A step of forming a brush layer in gaps in the pattern of the patterned underlayer film. Note that step 6 is a step performed between steps 4 and 5.

[0106] <Step 1 and Step I> Step 1 and Step I are steps of forming an underlayer film on a semiconductor substrate using the composition for forming an underlayer film of the present invention. The method for forming the underlayer film is not particularly limited, and examples thereof include the methods described above. That is, the underlayer film can be produced, for example, by applying the composition for forming an underlayer film on a semiconductor substrate and baking it.

[0107] From the viewpoint of optimally obtaining the effects of the present invention, the thickness of the underlayer film is preferably less than 10 nm, more preferably 9 nm or less, even more preferably 8 nm or less, and particularly preferably 7 nm or less, and may be 1 nm or more, 2 nm or more, or 3 nm or more.

[0108] <Steps 2, 3, and 4> Step 2 is a step of forming a resist film, either a photoresist film or an electron beam resist film, on the underlayer film. Step 3 is a step of irradiating the resist film with light or an electron beam and then developing the resist film to obtain a resist pattern. Step 4 is a step of etching the underlayer film using the resist pattern as a mask to form a patterned underlayer film.

[0109] The thickness of the resist film to be formed is not particularly limited, but is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, and particularly preferably 80 nm or less. The thickness of the resist film is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more.

[0110] The resist formed by coating and baking on the underlayer film by a known method is not particularly limited as long as it responds to light or electron beam (EB) used for irradiation. Both negative and positive photoresists can be used. In this specification, resists that respond to EB are also sometimes referred to as photoresists. Examples of photoresists include positive photoresists composed of a novolak resin and a 1,2-naphthoquinone diazide sulfonic acid ester; chemically amplified photoresists composed of a binder having a group that decomposes in the presence of an acid to increase the alkaline dissolution rate and a photoacid generator; chemically amplified photoresists composed of a low molecular weight compound that decomposes in the presence of an 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 the presence of an acid to increase the alkaline dissolution rate, a low molecular weight compound that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator; and resists containing metal elements. Examples of such photoresists include V146G (trade name) manufactured by JSR Corporation, APEX-E (trade name) manufactured by Shipley 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).

[0111] 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, WO201 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 2010-18 1857, 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. Resist compositions, radiation-sensitive resin compositions, high-resolution patterning compositions based on organometallic solutions, and metal-containing resist compositions can be used, but are not limited to these.

[0112] Examples of the resist composition include the following compositions.

[0113] 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 the following general formula (21):

[0114] In the general formula (21), m represents an integer of 1 to 6. １ and R ２ each independently represents a fluorine atom or a perfluoroalkyl group. １ is -O-, -S-, -COO-, -SO ２ - or -SO ３ - represents. ２ represents an alkylene group which may have a substituent or a single bond. １ represents a cyclic organic group which may have a substituent. ＋ represents a cation.

[0115] 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.

[0116] A radiation-sensitive resin composition comprising: a polymer having a first structural unit represented by the following formula (31) and a second structural unit represented by the following formula (32) containing an acid-dissociable group; and an acid generator.

[0117] In formula (31), 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. ２ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ３ is a monovalent group having 1 to 20 carbon atoms 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.

[0118] A resist composition comprising: a resin (A1) containing a structural unit having a cyclic carbonate structure, a structural unit represented by the following formula, and a structural unit having an acid labile group; and an acid generator.

[0119] [In the formula, R ２ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom; X １ represents 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.]

[0120] Examples of the resist film include the following.

[0121] A resist film comprising a base resin comprising 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 a polymer main chain upon exposure:

[0122] (In formula (a1) and formula (a2), R Ａ are each independently a hydrogen atom or a methyl group. １ and R ２ are 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. 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.

[0123] Examples of resist materials include the following:

[0124] A resist material comprising a polymer having a repeating unit represented by the following formula (b1) or (b2):

[0125] (In formula (b1) and formula (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 some 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 contained 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 ５ are 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 amide 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 ２may be bonded to form a ring together with the sulfur atom to which they are attached.

[0126] A resist material comprising a base resin containing a polymer containing a repeating unit represented by the following formula (a):

[0127] (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-CH ２ - or -NH-. m is an integer of 1 to 4. u is an integer of 0 to 3. However, m+u is an integer of 1 to 4.

[0128] A resist composition that generates an acid upon exposure, and whose solubility in a developer changes due to the action of the acid, comprising: a base component (A) whose solubility in a developer changes due to the action of the acid; and a fluorine additive component (F) that exhibits decomposition in an alkaline developer, wherein the fluorine additive component (F) comprises a fluororesin component (F1) that has a structural unit (f1) that includes a base dissociable group, and a structural unit (f2) that includes a group represented by the following general formula (f2-r-1):

[0129] [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.

[0130] 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).

[0131] [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 that does not have an acid-dissociable site. A ａｒｙｌ represents a divalent aromatic cyclic group which may have a substituent. ０１ is a single bond or a divalent linking group. ２ are each independently an organic group having a fluorine atom.

[0132] Coatings, coating solutions, and coating compositions include, for example:

[0133] A coating comprising a metal oxo-hydroxo network having organic ligands with metal carbon and / or metal carboxylate bonds.

[0134] Inorganic oxo / hydroxo-based compositions.

[0135] a coating solution comprising an organic solvent; a first organometallic composition having the formula R ｚ SnO （２－（ｚ／２）－（ｘ／２）） (OH) ｘ (where 0<z≦2 and 0<(z+x)≦4), formula R′ ｎ SnX ４－ｎ wherein n=1 or 2, or mixtures 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 having the formula MX′ ｖ wherein 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.

[0136] an organic solvent and a solution of the formula RSnO （３／２－ｘ／２） (OH) ｘand a first organometallic compound of the formula: wherein 0<x<3, wherein the solution contains from about 0.0025M to about 1.5M tin, and R is an alkyl or cycloalkyl group having from 3 to 31 carbon atoms, the alkyl or cycloalkyl group being bonded to the tin at a secondary or tertiary carbon atom.

[0137] An aqueous inorganic patterning precursor solution comprising a mixture of water, metal suboxide cations, polyatomic inorganic anions, and radiation-sensitive ligands comprising peroxide groups.

[0138] The irradiation with light or electron beam is carried out, for example, through a mask (reticle) for forming a predetermined pattern. The wavelength of the light is not particularly limited. The underlayer film of the present invention is suitably applied to EB (electron beam) or EUV (extreme ultraviolet: 13.5 nm) irradiation, but is more preferably applied to EUV (extreme ultraviolet) exposure. The EB irradiation energy and EUV exposure dose are not particularly limited.

[0139] After irradiation with light or electron beams and before development, baking (PEB: Post Exposure Bake) may be performed. The baking temperature is not particularly limited, but is preferably 60° C. to 150° C., more preferably 70° C. to 120° C., and particularly preferably 75° C. to 110° C. The baking time is not particularly limited, but is preferably 1 second to 10 minutes, more preferably 10 seconds to 5 minutes, and particularly preferably 30 seconds to 3 minutes.

[0140] For example, an alkaline developer is used for development. The development temperature is, for example, 5°C to 50°C. The development time is, for example, 10 seconds to 300 seconds. Examples of alkaline developers that can be used include aqueous solutions of alkalis such as inorganic alkalis (e.g., sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia); primary amines (e.g., ethylamine and n-propylamine); secondary amines (e.g., diethylamine and di-n-butylamine); tertiary amines (e.g., triethylamine and methyldiethylamine); alcohol amines (e.g., dimethylethanolamine and triethanolamine); quaternary ammonium salts (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline); and cyclic amines (e.g., pyrrole and piperidine). Furthermore, the aqueous solutions of the alkalis may be used by adding an appropriate amount of alcohols (e.g., isopropyl alcohol) or a nonionic surfactant. Among these, preferred developers are aqueous solutions of quaternary ammonium salts, more preferably aqueous solutions of tetramethylammonium hydroxide and choline. Furthermore, surfactants and the like may also be added to these developers. Alternatively, development may be carried out with an organic solvent such as butyl acetate instead of an alkaline developer, and the portions of the photoresist where the alkaline dissolution rate is not improved may be developed.

[0141] The type of resist pattern to be formed is not particularly limited, and may be a line pattern or a hole pattern. When the resist pattern is a line pattern, the line width is not particularly limited, and may be, for example, 30 nm to 200 nm. When the resist pattern is a hole pattern, the diameter of the hole may be, for example, 30 nm to 200 nm.

[0142] Next, the underlayer film is etched using the formed resist pattern as a mask. The etching may be dry etching or wet etching, but dry etching is preferred.

[0143] After the fourth step, a step of removing the resist pattern may be included. The removal of the resist pattern is carried out, for example, by etching. The etching may be dry etching or wet etching. The removal of the resist pattern is usually carried out before the fifth step.

[0144] <Step 5 and Step II> Step 5 is a step of forming a self-assembled film on a patterned underlayer film. Step II is a step of forming a self-assembled film on the underlayer film. The self-assembled film can be formed, for example, by applying a composition for forming a self-assembled film and drying it. The self-assembled film is, for example, a film containing a block copolymer.

[0145] The thickness of the self-assembled film is not particularly limited, but is preferably 10 nm to 100 nm, more preferably 30 nm to 80 nm, and particularly preferably 40 nm to 60 nm.

[0146] <<Self-Assembled Film-Forming Composition>> The self-assembled film-forming composition contains, for example, a block copolymer. The self-assembled film-forming composition usually contains a solvent.

[0147] The solids content of the self-assembled film-forming composition can be 0.1 to 10% by mass, or 0.1 to 5% by mass, or 0.1 to 3% by mass. The solids content is the percentage remaining after removing the solvent from the film-forming composition. The proportion of the block copolymer in the solids content can be 30 to 100% by mass, or 50 to 100% by mass, or 50 to 90% by mass, or 50 to 80% by mass. The number of types of blocks present in the block copolymer can be two or three or more. The number of blocks present in the block copolymer can be two or three or more.

[0148] <<<Block Copolymers>>> Block polymers include combinations such as AB, ABAB, ABA, and ABC. Methods for synthesizing block copolymers include living radical polymerization and living cationic polymerization, in which the polymerization process consists only of an initiation reaction and a propagation reaction, and does not involve side reactions that deactivate the growing ends. The growing ends can maintain their propagation activity during the polymerization reaction. By preventing chain transfer, a polymer (PA) of uniform length can be obtained. By adding a different monomer (mb), the growing end of this polymer (PA) can be used to polymerize the monomer (mb) and form a block copolymer (AB).

[0149] For example, when there are two types of blocks, PA and PB, the molar ratio of the polymer chain (PA) to the polymer chain (PB) can be 1:9 to 9:1, preferably 3:7 to 7:3. The volume ratio of the block copolymer is, for example, 30:70 to 70:30. The homopolymer PA or PB is a polymer of a polymerizable compound having at least one radically polymerizable reactive group (vinyl group or vinyl group-containing organic group).

[0150] The weight average molecular weight Mw of the block copolymer is preferably 1,000 to 100,000, or 5,000 to 100,000. A molecular weight Mw of 1,000 or more provides excellent coatability onto the base substrate, while a molecular weight Mw of 100,000 or less provides excellent solubility in solvents. The polydispersity index (Mw / Mn) of the block copolymer is preferably 1.00 to 1.50, and more preferably 1.00 to 1.20.

[0151] Known block copolymers can be used in the present invention. Specific examples of block copolymers include a combination of a silicon-containing polymer chain and a silicon-free polymer chain, which is preferable because it can increase the difference in dry etching rate. Examples of silicon-containing polymer chains include silylated polystyrene derivatives. Examples of silylated polystyrene derivatives include polysilanes (e.g., polydihexylsilane), polysiloxanes (e.g., polydimethylsiloxane), poly(trimethylsilylstyrene), and poly(pentamethyldisilylstyrene). In particular, the silylated polystyrene derivatives are preferably poly(4-trimethylsilylstyrene) and poly(4-pentamethyldisilylstyrene), which have a substituent at the 4-position.

[0152] A preferred example of the block copolymer is a block copolymer obtained by combining a silicon-containing polymer having a structural unit of styrene, which may be substituted with an organic group, or a silicon-containing polymer having a structural unit derived from lactide, with a silicon-containing polymer having a structural unit of styrene substituted with a silicon-containing group. Among these, a combination of a silylated polystyrene derivative and a polystyrene derivative, or a combination of a silylated polystyrene derivative and polylactide is preferred. Among these, a combination of a silylated polystyrene derivative having a substituent at the 4-position and a polystyrene derivative having a substituent at the 4-position, or a combination of a silylated polystyrene derivative having a substituent at the 4-position and polylactide is preferred. More preferred examples of the block copolymer include a combination of poly(trimethylsilylstyrene) and polymethoxystyrene, a combination of polystyrene and poly(trimethylsilylstyrene), and a combination of poly(trimethylsilylstyrene) and poly(D,L-lactide). More preferred specific examples of the block copolymer include a combination of poly(4-trimethylsilylstyrene) and poly(4-methoxystyrene), a combination of polystyrene and poly(4-trimethylsilylstyrene), and a combination of poly(4-trimethylsilylstyrene) and poly(D,L-lactide). Most preferred specific examples of the block copolymer include a poly(4-methoxystyrene) / poly(4-trimethylsilylstyrene) block copolymer and a polystyrene / poly(4-trimethylsilylstyrene) block copolymer. The entire disclosure of WO2018 / 135456 is incorporated herein by reference.

[0153] The block copolymer may be a block copolymer obtained by bonding a non-silicon-containing polymer with a silicon-containing polymer having a structural unit of styrene substituted with a silicon-containing group, and the non-silicon-containing polymer may be a block copolymer containing a unit structure represented by the following formula (1-1c) or formula (1-2c):

[0154] (In formula (1-1c) or formula (1-2c), R １ and R２ each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms; R ３ ~R ５ each independently represents a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, an amino group, an amido group, or a carbonyl group.

[0155] The silicon-containing group may contain one silicon atom. The silicon-containing polymer may contain a unit structure represented by the following formula (2c):

[0156] (In formula (2c), R ６ ~R ８ each independently represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms.

[0157] Furthermore, the block copolymer may be one described in JP-T-2019-507815 A, including the following [BCP11] to [BCP14]. The entire disclosure of JP-T-2019-507815 A is incorporated herein by reference. [BCP11]: A block copolymer containing 5-vinylbenzo[d][1,3]dioxole. [BCP12]: The block copolymer described in [BCP11], wherein the block copolymer further contains a silicon-containing block. [BCP13]: The block copolymer described in [BCP12], wherein the block copolymer further contains pentamethyldisilylstyrene. [BCP14]: The block copolymer described in [BCP13], wherein the block copolymer is poly(5-vinylbenzo[d][1,3]dioxole)-b-poly(pentamethyldisilylstyrene).

[0158] The synthesis of the above-described poly(5-vinylbenzo[d][1,3]dioxole-block-4-pentamethyldisilylstyrene) is shown in Scheme 1 below.

[0159] Me represents a methyl group.

[0160] Preferably, the silicon-containing polymer or silicon-containing block is poly(4-trimethylsilylstyrene) derived from 4-trimethylsilylstyrene. Preferably, the silicon-containing polymer or silicon-containing block is poly(pentamethyldisilylstyrene) derived from pentamethyldisilylstyrene. The aryl group having 6 to 40 carbon atoms refers to a monovalent group of a monocyclic or polycyclic aromatic hydrocarbon having 6 to 40 carbon atoms, and specific examples include a phenyl group, a naphthyl group, and an anthryl group. The entire disclosure of WO2020 / 017494 is incorporated herein by reference.

[0161] Also, a block copolymer made of a combination of the following monomers may be used: styrene, methyl methacrylate, dimethylsiloxane, propylene oxide, ethylene oxide, vinylpyridine, vinylnaphthalene, D,L-lactide, methoxystyrene, methylenedioxystyrene, trimethylsilylstyrene, and pentamethyldisilylstyrene.

[0162] Useful block copolymers contain at least two blocks and may be diblock, triblock, tetrablock, etc. copolymers with distinct blocks, each of which may be a homopolymer or a random or alternating copolymer.

[0163] Typical block copolymers include polystyrene-b-polyvinylpyridine, polystyrene-b-polybutadiene, polystyrene-b-polyisoprene, polystyrene-b-polymethylmethacrylate, polystyrene-b-polyalkenyl aromatic, polyisoprene-b-polyethylene oxide, polystyrene-b-poly(ethylene-propylene), polyethylene oxide-b-polycaprolactone, polybutadiene-b-polyethylene oxide, polystyrene-b-poly(t-butyl (meth)acrylate), polymethylmethacrylate-b-poly(t-butyl methacrylate), polyethylene oxide-b-polypropylene oxide, polystyrene-b-polytetrafluoroethylene Examples of block copolymers include hydrofuran, polystyrene-b-polyisoprene-b-polyethylene oxide, poly(styrene-b-dimethylsiloxane), poly(methyl methacrylate-b-dimethylsiloxane), poly(methyl (meth)acrylate-r-styrene)-b-polymethyl methacrylate, poly(methyl (meth)acrylate-r-styrene)-b-polystyrene, poly(p-hydroxystyrene-r-styrene)-b-polymethyl methacrylate, poly(p-hydroxystyrene-r-styrene)-b-polyethylene oxide, polyisoprene-b-polystyrene-b-polyferrocenylsilane, or a combination comprising at least one of the foregoing block copolymers.

[0164] Further examples include block copolymers formed from a combination of the organic polymers and / or metal-containing polymers described below.

[0165] Typical organic polymers include poly(9,9-bis(6'-N,N,N-trimethylammonium)-hexyl)-fluorenephenylene) (PEP), poly(4-vinylpyridine) (4PVP), hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG), poly(ethylene oxide)-poly(propylene oxide) diblock or multiblock copolymers, polyvinyl alcohol (PVA), poly(ethylene-vinyl alcohol) (PEVA), polyacrylic acid (PAA), polylactic acid (PLA), poly(ethyloxazoline), poly(alkyl acrylate), poly(acrylic acid), poly(ethylene-vinyl alcohol ... Examples of suitable polyvinyl alcohols include, but are not limited to, polyvinyl amides, poly(N-alkylacrylamides), poly(N,N-dialkylacrylamides), polypropylene glycol (PPG), polypropylene oxide (PPO), partially or fully hydrogenated poly(vinyl alcohol), dextran, polystyrene (PS), polyethylene (PE), polypropylene (PP), polyisoprene (PI), polychloroprene (CR), polyvinyl ether (PVE), polyvinyl acetate (PVA), polyvinyl chloride (PVC), polyurethane (PU), polyacrylates, polymethacrylates, oligosaccharides, or polysaccharides.

[0166] Metal-containing polymers include, but are not limited to, silicon-containing polymers (e.g., polydimethylsiloxane (PDMS), polyhedral silsesquioxane (POSS), or poly(trimethylsilylstyrene) (PTMSS)) or polymers containing silicon and iron (e.g., poly(ferrocenyldimethylsilane) (PFS)).

[0167] Exemplary block copolymers include, but are not limited to, diblock copolymers [e.g., polystyrene-b-polydimethylsiloxane (PS-PDMS), poly(2-vinylpropylene)-b-polydimethylsiloxane (P2VP-PDMS), polystyrene-b-poly(ferrocenyldimethylsilane) (PS-PFS), or polystyrene-b-polyDL-lactic acid (PS-PLA)] or triblock copolymers [e.g., polystyrene-b-poly(ferrocenyldimethylsilane)-b-poly(2-vinylpyridine) (PS-PFS-P2VP), polyisoprene-b-polystyrene-b-poly(ferrocenyldimethylsilane) (PI-PS-PFS), or polystyrene-b-poly(ferrocenyldimethylsilane)-b-polystyrene (PS-PTMSS-PS)]. In one embodiment, the PS-PTMSS-PS block copolymer comprises a poly(trimethylsilylstyrene) polymer block composed of two chains of PTMSS connected by a linker containing four styrene units. Modified versions of block copolymers, such as those disclosed in U.S. Patent Application Publication No. 2012 / 0046415, are also contemplated.

[0168] Other block copolymers include, for example, a block copolymer in which a polymer having styrene or a derivative thereof as a constituent unit is bonded to a polymer having a (meth)acrylic acid ester as a constituent unit, a block copolymer in which a polymer having styrene or a derivative thereof as a constituent unit is bonded to a polymer having siloxane or a derivative thereof as a constituent unit, and a block copolymer in which a polymer having alkylene oxide as a constituent unit is bonded to a polymer having a (meth)acrylic acid ester as a constituent unit. Note that "(meth)acrylic acid ester" refers to either or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

[0169] Examples of (meth)acrylic acid esters include those in which a substituent such as an alkyl group or a hydroxyalkyl group is bonded to a carbon atom of (meth)acrylic acid. Examples of the alkyl group used as the substituent include linear, branched, or cyclic alkyl groups having 1 to 10 carbon atoms. Specific examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, benzyl (meth)acrylate, anthracene (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethane (meth)acrylate, and propyltrimethoxysilane (meth)acrylate.

[0170] Examples of styrene derivatives include α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, 2,4,6-trimethylstyrene, 4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene, vinylcyclohexane, 4-vinylbenzyl chloride, 1-vinylnaphthalene, 4-vinylbiphenyl, 1-vinyl-2-pyrrolidone, 9-vinylanthracene, and vinylpyridine.

[0171] Examples of siloxane derivatives include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, methylphenylsiloxane, etc. Examples of alkylene oxides include ethylene oxide, propylene oxide, isopropylene oxide, butylene oxide, etc.

[0172] Examples of the block copolymer include polystyrene / poly(methyl methacrylate) block copolymer, styrene-polyethyl methacrylate block copolymer, styrene-(poly-t-butyl methacrylate) block copolymer, styrene-polymethacrylic acid block copolymer, styrene-polymethyl acrylate block copolymer, styrene-polyethyl acrylate block copolymer, styrene-(poly-t-butyl acrylate) block copolymer, styrene-polyacrylic acid block copolymer, etc. The entire disclosure of WO2022 / 039187 is incorporated herein by reference.

[0173] <<<Solvents>>> Examples of solvents that can be used in the self-assembled film-forming composition include the following organic solvents: Aliphatic hydrocarbon solvents such as n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane, cyclohexane, and methylcyclohexane Aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i-propylbenzene, n-amylnaphthalene, and trimethylbenzene Methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, heptanol-3, n-octanol, 2-ethylhexanol, Monoalcohol solvents such as sec-octanol, n-nonyl alcohol, 2,6-dimethylheptanol-4, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethylcarbinol, diacetone alcohol, and cresol; Polyalcohol solvents such as ethylene glycol, propylene glycol, 1,3-butylene glycol, pentanediol-2,4, 2-methylpentanediol-2,4, hexanediol-2,5, heptanediol-2,4, 2-ethylhexanediol-1,3, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and glycerin.Ketone solvents such as acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl i-butyl ketone, methyl n-pentyl ketone, ethyl n-butyl ketone, methyl n-hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclohexanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, and fenchone Ethyl ether, i-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl Ether solvents such as ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran.Diethyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, di Ester solvents such as ethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, and diethyl phthalate. Nitrogen-containing solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, and N-methylpyrrolidone Sulfur-containing solvents such as dimethyl sulfide, diethyl sulfide, thiophene, tetrahydrothiophene, dimethyl sulfoxide, sulfolane, and 1,3-propane sultone

[0174] In particular, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monopropyl ether acetate are preferred in terms of storage stability of the solution of the composition.

[0175] Furthermore, the solvent contained in the composition for forming a self-assembled film may be a combination of a low-boiling point solvent (A) having a boiling point of 160°C or less and a high-boiling point solvent (B) having a boiling point of 170°C or more, as described in WO2018 / 135456.

[0176] Preferred examples of the low-boiling solvent (A) having a boiling point of 160°C or less include propylene glycol monomethyl ether acetate (boiling point: 146°C), n-butyl acetate (boiling point: 126°C), and methyl isobutyl ketone (boiling point: 116°C).

[0177] Preferred examples of the high-boiling solvent (B) having a boiling point of 170°C or higher include N-methylpyrrolidone (boiling point: 204°C), diethylene glycol monomethyl ether (boiling point: 193°C), N,N-dimethylisobutyramide (boiling point: 175°C), 3-methoxy-N,N-dimethylpropanamide (boiling point: 215°C), and γ-butyrolactone (boiling point: 204°C).

[0178] Two or more low-boiling point solvents (A) and two or more high-boiling point solvents (B) may be selected and mixed for use.

[0179] In a preferred embodiment, the composition contains 0.3 to 2.0 wt% of the high-boiling point solvent (B) relative to the total weight of the solvents contained in the composition. Most preferably, the composition contains 0.5 to 1.5 wt% of the high-boiling point solvent (B). The entire disclosure of WO2018 / 135456 is incorporated herein by reference.

[0180] <<Phase Separation of Self-Assembled Monolayers>> Phase separation of a self-assembled monolayer (e.g., a block copolymer film) can be achieved by a treatment that brings about rearrangement of the self-assembled monolayer, such as ultrasonic treatment, solvent treatment, or thermal annealing. In many applications, it is desirable to achieve phase separation of a self-assembled monolayer by simple heating or so-called thermal annealing. Thermal annealing can be performed in the atmosphere or in an inert gas under normal pressure, reduced pressure, or increased pressure. The conditions for thermal annealing are not particularly limited, but are preferably 180°C to 300°C in the atmosphere, more preferably 210°C to 280°C, and particularly preferably 230°C to 270°C. The treatment time is not particularly limited, but is usually 1 minute to 30 minutes, preferably 3 minutes to 10 minutes.

[0181] Phase separation of the self-assembled monolayer forms domains oriented substantially perpendicular to the surface of the substrate or underlying film. The domains may have, for example, a lamellar, spherical, or cylindrical shape. The domain spacing is, for example, 50 nm or less.

[0182] <<Patterning of Self-Assembled Monolayers>> A pattern corresponding to the morphology of the domains can be obtained by selectively removing portions of a phase-separated self-assembled monolayer. Examples of methods for selectively removing portions of a phase-separated self-assembled monolayer include a method of subjecting the phase-separated self-assembled monolayer to oxygen plasma treatment or hydrogen plasma treatment.

[0183] <Sixth Step> The sixth step is a step of forming a brush layer in gaps between patterns of the patterned underlayer film. Note that the sixth step is a step performed between the fourth step and the fifth step.

[0184] The method for forming the brush layer is not particularly limited, but may be, for example, a method in which a brush layer-forming composition is applied and dried.

[0185] <<Brush Layer-Forming Composition>> The brush layer-forming composition contains, for example, a brush polymer and a solvent. The brush layer-forming composition is, for example, a composition containing polymer chains capable of directly bonding to the substrate surface. A film or layer formed by polymer chains arranged in a brush-like pattern on a substrate is sometimes called a brush layer. The brush layer-forming composition is, for example, a composition for forming an underlayer film for forming an underlayer film of a layer containing a block copolymer. Furthermore, a film formed from the brush layer-forming composition serves, for example, as a guide that controls the position of the polymer phase formed by self-assembly. For example, a film formed from the brush layer-forming composition has a concave-convex structure and serves as the sidewall of a recess in a physical guide (grapho-epitaxy) for forming a microphase-separated pattern in the recess. Furthermore, for example, a film formed from the brush layer-forming composition is, for example, a chemical guide (chemical-epitaxy) that is formed under a self-assembling material and controls the position of the microphase-separated pattern based on the difference in surface energy.

[0186] <<<Brush Polymer>>> The brush polymer is not particularly limited as long as it is a brush polymer used in forming the underlayer film.

[0187] An example of a brush polymer is a polymer having a neutral wetting bottom surface, as described in JP-A-2011-515537. Examples of such a polymer include a random copolymer as described in claim 15 of JP-A-2011-515537 and a grafted blend of multiple homopolymers as described in claim 16. The contents of JP-A-2011-515537 are incorporated herein by reference to the same extent as if expressly set forth in its entirety.

[0188] Another example of the brush polymer is the random copolymer described in JP-T-2011-518652. One example of the random copolymer described in JP-T-2011-518652 is the photocrosslinkable random PS-r-PMMA described in paragraph

[0028] . The contents of JP-T-2011-518652 are incorporated herein by reference to the same extent as if set forth in their entirety.

[0189] Another example of a brush polymer is a resin in which 20 mol % to 80 mol % of the total structural units are derived from aromatic ring-containing monomers. Such a resin is, for example, the resin component contained in the primer described in WO 2012 / 036121. The contents of WO 2012 / 036121 are incorporated herein by reference in their entirety.

[0190] Another example of the brush polymer is the random copolymer described in claim 1 of JP 2013-166934 A. The contents of JP 2013-166934 A are incorporated herein by reference in their entirety to the same extent as if set forth explicitly herein.

[0191] Another example of the brush polymer is a polymer having 0.2 mol% or more of a polycyclic aromatic vinyl compound unit structure per total unit structure. Examples of such polymers include the polymers contained in the underlayer film-forming composition described in International Publication No. 2014 / 097993. The contents of International Publication No. 2014 / 097993 are incorporated herein by reference in their entirety.

[0192] Another example of a brush polymer is the polymer contained in the brush backfill composition described in JP 2015-130496 A (e.g., poly(alkyl acrylate) having functional groups capable of reacting with semiconductor substrates), the contents of which are incorporated herein by reference in their entirety to the same extent as if set forth herein.

[0193] Another example of the brush polymer is the addition polymer described in claim 1 of JP 2016-148024 A. The contents of JP 2016-148024 A are incorporated herein by reference in their entirety to the same extent as if set forth explicitly herein.

[0194] Another example of the brush polymer is the polymer contained in the pinning material described in claim 1 of JP-T-2016-528713. Such a polymer is, for example, the polymer described in claim 3 of JP-T-2016-528713. The contents of JP-T-2016-528713 are incorporated herein by reference in their entirety to the same extent as if set forth explicitly herein.

[0195] Another example of a brush polymer is an acid-sensitive copolymer comprising an acid-decomposable group, an attachment group, and a functional group, as described in claim 1 of JP 2018-139007 A. The contents of JP 2018-139007 A are incorporated herein by reference in their entirety to the same extent as if set forth herein.

[0196] Another example of the brush polymer is the hydrophobic polymer brush precursor described in claim 1 of JP-T-2018-503241, the contents of which are incorporated herein by reference in their entirety to the same extent as if set forth herein.

[0197] The brush polymer preferably has a functional group capable of bonding to a substrate. Examples of functional groups capable of bonding to a substrate include a hydroxy group, an amino group, and a sulfonic acid group. The brush polymer may have the functional group capable of bonding to a substrate at the end of the polymer chain, or at a location other than the end of the polymer chain. There are no particular limitations on the method for introducing the functional group capable of bonding to a substrate into the end of the polymer chain. For example, in the case of an addition polymerization type polymer, a method may be used in which a compound having a functional group capable of bonding to a substrate is used as a polymerization initiator or chain transfer agent.

[0198] The brush polymer is preferably an addition polymerization type polymer obtained, for example, by polymerizing one or more radically polymerizable monomers.

[0199] The radical polymerizable monomer is not particularly limited, and examples thereof include (meth)acrylic compounds, aromatic group-containing vinyl compounds, etc. Examples of the (meth)acrylic compound include (meth)acrylic acid, (meth)acrylic acid esters, etc. Examples of the (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, and tert-butyl (meth)acrylate. Examples of aromatic group-containing vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, 2,4,6-trimethylstyrene, 4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene, vinylcyclohexane, 4-vinylbenzyl chloride, 1-vinylnaphthalene, 4-vinylbiphenyl, 1-vinyl-2-pyrrolidone, 9-vinylanthracene, and vinylpyridine.

[0200] <<<<<Polymer (P)>>>> The brush polymer is preferably a polymer (P) containing the following structural units (A) and (B), in that a microphase-separated structure of the block copolymer can be induced perpendicular to the substrate. Structural unit (A): a structural unit derived from a (meth)acrylic compound having a (meth)acryloyl group and a functional group capable of bonding to the substrate. Structural unit (B): a structural unit derived from an aromatic group-containing vinyl compound.

[0201] The molar ratio of the structural unit (A) to all structural units in the polymer (P) is more than 0% and not more than 5%. When the molar ratio of the structural unit (A) to all structural units in the polymer (P) is more than 0% and not more than 5%, a film can be formed in which a microphase-separated structure of the block copolymer is induced perpendicular to the substrate. When the molar ratio of the structural unit (A) to all structural units in the polymer (P) exceeds 5%, the arrangement of the microphase-separated structure of the block copolymer becomes disordered, and it is not possible to induce a microphase-separated structure of the block copolymer perpendicular to the substrate.

[0202] The polymer (P) is not particularly limited as long as it contains the structural units (A) and (B), but is preferably an addition polymer obtained by polymerizing a compound having a polymerizable unsaturated group. Examples of the polymerizable unsaturated group include an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group.

[0203] The polymer (P) is, for example, a random copolymer.

[0204] The polymer (P) may contain structural units other than the structural units (A) and (B).

[0205] The structural unit (A) is a structural unit derived from a (meth)acrylic compound. The (meth)acrylic compound has a (meth)acryloyl group. The (meth)acrylic compound has a functional group capable of bonding to a substrate. The (meth)acryloyl group is a notation that indicates an acryloyl group and a methacryloyl group. The acryloyl group is a CH ２ =CH-CO-, and a methacryloyl group is a group represented by CH ２ =C(CH ３ )-CO-.

[0206] The functional group capable of bonding to a substrate is not particularly limited, and examples thereof include a hydroxy group, an amino group, and a sulfonic acid group. The number of functional groups capable of bonding to a substrate in the structural unit (A) may be one or two or more, but is preferably one. The number of (meth)acryloyl groups in the (meth)acrylic compound may be one or two or more, but is preferably one.

[0207] The structural unit (A) is a structural unit different from the structural unit (B), and therefore the structural unit (B) does not have an aromatic ring.

[0208] The structural unit (A) in the polymer (P) may be of one type or of two or more types.

[0209] The structural unit (A) preferably contains a structural unit (A-1) represented by the following formula (1).

[0210] (In formula (1), X represents —O— or —NH—. Y represents a hydroxy group, an amino group, or a sulfonic acid group. R １ represents an alkylene group having 1 to 10 carbon atoms which may be substituted with a halogen atom. ２ represents a hydrogen atom or a methyl group.

[0211] The amino group is preferably a primary amino group or a secondary amino group. A primary amino group is a monovalent functional group (—NH ２ A secondary amino group refers to a monovalent functional group (-NHR (wherein R represents an organic group) formed by removing a hydrogen atom from a primary amine. R represents, for example, an alkyl group having 1 to 6 carbon atoms.

[0212] The alkylene group having 1 to 10 carbon atoms and optionally substituted with a halogen atom may be linear, branched, or cyclic. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The number of halogen atoms in the alkylene group having 1 to 10 carbon atoms and optionally substituted with a halogen atom may be one or two or more.

[0213] The alkylene group having 1 to 10 carbon atoms may be a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, a 1,3-propylene group (a trimethylene group), a 1-methylethylene group (a 1,2-propylene group), a 1,4-butylene group, a 1-ethylethylene group, a 1-methylpropylene group, a 2-methylpropylene group, a 1,5-pentylene group, a 1-methylbutylene group, a 2-methylbutylene group, a 1,1-dimethylpropylene group, a 1,2-dimethylpropylene group, a 1-ethylpropylene group, a 2-ethylpropylene group, a 1,6-hexylene group, a 1,4-cyclohexylene group, a 1,8-octylene group, a 2-ethyloctylene group, a 1,9-nonylene group, and a 1,10-decylene group.

[0214] The molar ratio of the structural unit (A) to all structural units in the polymer (P) is more than 0% and 5% or less, preferably 0.1% or more and 5% or less, more preferably 0.3% or more and 4.5% or less, and particularly preferably 0.5% or more and 4.0% or less.

[0215] Examples of the (meth)acrylic compound include compounds represented by the following formula (1-1).

[0216] (In formula (1-1), X represents —O— or —NH—. Y represents a hydroxy group, an amino group, or a sulfonic acid group. R １ represents an alkylene group having 1 to 10 carbon atoms which may be substituted with a halogen atom. ２ represents a hydrogen atom or a methyl group.

[0217] Examples of the (meth)acrylic compound include hydroxy group-containing (meth)acrylates, amino group-containing (meth)acrylates, sulfonic acid group-containing (meth)acrylates, hydroxy group-containing (meth)acrylamides, and sulfonic acid group-containing (meth)acrylamides.

[0218] Examples of hydroxy group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and 1,4-cyclohexanedimethanol mono(meth)acrylate.

[0219] Examples of amino group-containing (meth)acrylates include primary amino group-containing (meth)acrylates and secondary amino group-containing (meth)acrylates. Examples of primary amino group-containing (meth)acrylates include aminomethyl (meth)acrylate and aminoethyl (meth)acrylate. Examples of secondary amino group-containing (meth)acrylates include t-butylaminoethyl (meth)acrylate and t-butylaminopropyl (meth)acrylate.

[0220] Examples of sulfonic acid group-containing (meth)acrylates include 2-sulfoethyl (meth)acrylate and 3-sulfopropyl (meth)acrylate.

[0221] Examples of hydroxy group-containing (meth)acrylamides include N-(hydroxymethyl)(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and N-(4-hydroxybutyl)(meth)acrylamide.

[0222] The structural unit (B) is a structural unit derived from an aromatic group-containing vinyl compound. The aromatic ring contained in the aromatic group-containing vinyl compound may be an aromatic hydrocarbon ring or an aromatic heterocycle, but an aromatic hydrocarbon ring is preferred. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. The aromatic group-containing vinyl compound does not have, for example, a functional group capable of bonding to a substrate. The aromatic group-containing vinyl compound does not have, for example, a hydroxy group, an amino group, or a sulfonic acid group.

[0223] The structural unit (B) does not have, for example, a functional group capable of bonding to a substrate, such as a hydroxy group, an amino group, or a sulfonic acid group.

[0224] The structural unit (B) in the polymer (P) may be of one type or of two or more types.

[0225] The structural unit (B) preferably contains a structural unit (B-1) represented by the following formula (2): The structural unit (B) preferably contains a structural unit (B-2) represented by the following formula (3):

[0226] (In formula (2), n Ys each independently represent a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, or a thioalkyl group, and n represents an integer of 0 to 7.)

[0227] (In formula (3), R ３ ~R ５ each independently represents a hydrogen atom or a tert-butyl group. ３ ~R ５ One or two of represents a tert-butyl group.

[0228] Examples of the halogen atom for Y in formula (2) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The alkyl group for Y in formula (2) is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 to 3 carbon atoms. The alkyl group may be linear, branched, or cyclic. The alkoxy group for Y in formula (2) is preferably an alkoxy group having 1 to 15 carbon atoms, more preferably an alkoxy group having 1 to 10 carbon atoms, even more preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably an alkoxy group having 1 to 3 carbon atoms. The alkyl group in the alkoxy group may be linear, branched, or cyclic. The alkoxycarbonyl group for Y in formula (2) is preferably an alkoxycarbonyl group having 2 to 15 carbon atoms, more preferably an alkoxycarbonyl group having 2 to 10 carbon atoms, even more preferably an alkoxycarbonyl group having 2 to 6 carbon atoms, and particularly preferably an alkoxycarbonyl group having 2 to 3 carbon atoms. The alkyl group in the alkoxycarbonyl group may be linear, branched, or cyclic. Examples of the thioalkyl group for Y in formula (2) include groups in which -O- of the above alkoxy group is replaced with -S-.

[0229] The molar ratio of the structural unit (B) to all structural units in the polymer (P) is not particularly limited, but is preferably 80% or more and less than 100%, more preferably 90% or more and less than 100%, and particularly preferably more than 95% and less than 100%.

[0230] The molar ratio of the structural unit (A) to the structural unit (B) in the polymer (P) (structural unit (A):structural unit (B)) is not particularly limited, but is preferably 1:200 to 1:10, and more preferably 1:150 to 1:20.

[0231] When the polymer (P) contains the structural unit (B-1) represented by formula (2), the molar ratio of the structural unit (A) to the structural unit (B-1) in the polymer (P) (structural unit (A):structural unit (B-1)) is not particularly limited, but is preferably 1:100 to 1:5, and more preferably 1:75 to 1:10.

[0232] When the polymer (P) contains the structural unit (B-2) represented by formula (3), the molar ratio of the structural unit (A) to the structural unit (B-2) in the polymer (P) (structural unit (A):structural unit (B-2)) is not particularly limited, but is preferably 1:100 to 1:5, and more preferably 1:75 to 1:10.

[0233] When the polymer (P) contains the structural unit (B-1) represented by formula (2) and the structural unit (B-2) represented by formula (3), the molar ratio of the structural unit (B-1) to the structural unit (B-2) in the polymer (P) (structural unit (B-1):structural unit (B-2)) is not particularly limited, but is preferably 1.0:0.1 to 0.1:1.0, more preferably 1.0:0.5 to 0.5:1.0, and particularly preferably 1.0:0.7 to 0.7:1.0.

[0234] Examples of the aromatic group-containing vinyl compound include a compound represented by the following formula (2-1) and a compound represented by the following formula (3-1).

[0235] (In formula (2-1), n ​​Ys each independently represent a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, or a thioalkyl group, and n represents an integer of 0 to 7.)

[0236] (In formula (3-1), R ３ ~R ５ each independently represents a hydrogen atom or a tert-butyl group. ３ ~R ５ One or two of represents a tert-butyl group.

[0237] The weight average molecular weight of the brush polymer measured by gel permeation chromatography (GPC) is not particularly limited, but is, for example, 1,000 to 50,000, and preferably 2,000 to 20,000, in terms of polystyrene.

[0238] <<<<<Method for Producing Brush Polymers>>>> The method for producing a brush polymer is not particularly limited. For example, when the brush polymer is an addition polymerization type polymer, it can be produced by polymerizing monomers by a conventional method, such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization. Solution polymerization is particularly preferred, and in this case, for example, polymerization can be carried out by adding the desired monomer to a solvent to which a polymerization initiator has been added. For example, when the brush polymer is an addition polymerization type random copolymer, it can be produced by copolymerizing various monomers to an appropriate molar ratio by a conventional method, such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization. Examples of such polymerization include radical polymerization. The brush polymer can also be produced by a polymerization method other than radical polymerization. For example, it can be produced by ionic (anionic or cationic) addition polymerization, polycondensation, or polyaddition reaction.

[0239] The polymer (P) can be produced, for example, by solution polymerization of a monomer mixture containing a (meth)acrylic compound having a (meth)acryloyl group and a functional group capable of bonding to a substrate, and an aromatic group-containing vinyl compound.

[0240] [Polymerization Initiator] As the polymerization initiator, an organic peroxide or a diazo compound can be used.

[0241] Examples of organic peroxides include diacyl peroxides, peroxydicarbonates, peroxyesters, and peroxysulfonates. Examples of diacyl peroxides include diacetyl peroxide, diisobutyl peroxide, didecanoyl peroxide, benzoyl peroxide, and succinic acid peroxide. Examples of peroxydicarbonates include diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diallyl peroxydicarbonate. Examples of peroxyesters include tert-butyl peroxyisobutyrate, tert-butyl neodecanoate, and cumene peroxyneodecanate. Examples of peroxysulfonates include acetylcyclohexylsulfonyl peroxide.

[0242] Examples of diazo compounds include 2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(4-methoxy-2,4-dimethoxyvaleronitrile), and 2,2'-azobis(2-cyclopropylpropionitrile).

[0243] When it is desired to complete the polymerization in a short time, it is preferable to use a polymerization initiator having a decomposition half-life of 10 hours or less at 80° C. As such a polymerization initiator, benzoyl peroxide and 2,2′-azobisisobutyronitrile are preferred, and 2,2′-azobisisobutyronitrile is more preferred.

[0244] The amount of the polymerization initiator used is, for example, 0.0001 to 0.2 equivalents, and preferably 0.0005 to 0.1 equivalents, based on the total amount of the monomers used.

[0245] [Solvent] The solvent used in the polymerization is not particularly limited as long as it is inert to the polymerization reaction and compatible with the resulting brush polymer. Examples of the solvent include aromatic hydrocarbons, alicyclic hydrocarbons, aliphatic hydrocarbons, ketones, ethers, esters, amides, sulfoxides, alcohols, and polyhydric alcohol derivatives. Examples of aromatic hydrocarbons include benzene, toluene, and xylene. Examples of alicyclic hydrocarbons include cyclohexane. Examples of aliphatic hydrocarbons include n-hexane and n-octane. Examples of ketones include acetone, methyl ethyl ketone, and cyclohexanone. Examples of ethers include tetrahydrofuran and dioxane. Examples of esters include ethyl acetate and butyl acetate. Examples of amides include N,N-dimethylformamide and N,N-dimethylacetamide. Examples of sulfoxides include dimethyl sulfoxide. Examples of alcohols include methanol and ethanol. Examples of polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc. These may be used alone or in combination of two or more.

[0246] The polymerization temperature is not particularly limited as long as it is within a temperature range in which side reactions such as transfer reactions and termination reactions do not occur and the monomer is consumed to complete the polymerization, but it is preferably carried out within a temperature range of -100°C or higher and the boiling point of the solvent or lower. The concentration of the monomer relative to the solvent is not particularly limited, but is usually 1 to 40% by mass, preferably 10 to 30% by weight. The polymerization reaction time can be appropriately selected, but is usually within a range of 2 to 50 hours.

[0247] <<<Solvent>>> The solvent contained in the brush layer-forming composition is not particularly limited as long as it dissolves the brush polymer. Examples of the solvent include propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monopropyl ether, methyl ethyl ketone, ethyl lactate, cyclohexanone, N,N-2-trimethylpropionamide, γ-butyrolactone, N-methyl-2-pyrrolidone, methyl 2-hydroxyisobutyrate, and ethyl 3-ethoxypropionate. These can be used alone or in combination of two or more.

[0248] The content of the solvent in the brush layer-forming composition is not particularly limited, but is, for example, 90% by mass or more and 99.9% by mass or less.

[0249] <<<Other Components>>> The brush layer-forming composition preferably does not contain a crosslinking agent. For example, by reacting the brush polymer with the substrate, the film obtained from the brush layer-forming composition becomes a film that is insoluble in the solvent contained in the self-assembled film-forming composition containing the block copolymer. Therefore, the brush layer-forming composition does not need to contain a crosslinking agent. In the present invention, "not containing a crosslinking agent" may also include the inclusion of a small amount of crosslinking agent to the extent that it does not fully function as a crosslinking agent. In an embodiment in which the brush layer-forming composition does not contain a crosslinking agent, the content of the crosslinking agent in the brush layer-forming composition is preferably less than 0.1% by mass, more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less, relative to the brush polymer.

[0250] Examples of the crosslinking agent include nitrogen-containing compounds having 2 to 4 nitrogen atoms substituted with methylol groups or alkoxymethyl groups.

[0251] Examples of crosslinking agents include hexamethoxymethylmelamine, tetramethoxymethylglycoluril, tetramethoxymethylbenzoguanamine, 1,3,4,6-tetrakis(methoxymethyl)glycoluril, 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.

[0252] The brush layer-forming composition may contain a surfactant. The surfactant is an additive for improving the coatability to the substrate. Known surfactants such as nonionic surfactants and fluorine-based surfactants can be used as the surfactant. The content of the surfactant in the brush layer-forming composition is, for example, 0.1% by mass to 5% by mass relative to the brush polymer.

[0253] In the brush layer-forming composition, if the components excluding the solvent are defined as the solid content, the solid content includes the brush polymer and additives added as needed. The concentration of the solid content in the brush layer-forming composition is not particularly limited, but is, for example, 0.1% by mass to 15% by mass, and preferably 0.1% by mass to 10% by mass.

[0254] An example of a method for manufacturing a semiconductor device of the present invention will be described with reference to the drawings. FIGS. 1A to 1I are schematic cross-sectional views illustrating an example of the method for manufacturing a semiconductor device of the present invention. An underlayer film 2 is formed on a semiconductor substrate 1 using an underlayer film-forming composition of the present invention ( FIG. 1A ). Next, a resist film 3 is formed on the underlayer film 2 ( FIG. 1B ). Next, the resist film 3 is irradiated with light or an electron beam, and then developed to obtain a resist pattern (patterned resist film 3) ( FIG. 1C ). Next, the underlayer film 2 is etched using the resist pattern (patterned resist film 3) as a mask to form a patterned underlayer film 2 ( FIG. 1D ). Next, the resist pattern (patterned resist film 3) is removed ( FIG. 1E ). Next, a brush layer-forming composition is applied to the semiconductor substrate 1 and the patterned underlayer film 2 to form a brush layer 4 ( FIG. 1F ). Next, portions of the brush layer 4 are removed, and the brush layer 4 is formed in the gaps in the pattern of the patterned underlayer film 2 ( FIG. 1G ). Next, a self-assembled film 5 is formed on the patterned underlayer film 2 and brush layer 4. The self-assembled film 5 is, for example, a film of a block copolymer having an A block and a B block. By phase-separating the self-assembled film 5, a microphase-separated structure having A block domains 5a and B block domains 5b is obtained ( FIG. 1H ). By selectively removing a portion of the microphase-separated self-assembled film 5 (e.g., B block domains 5b), a pattern corresponding to the morphology of the microphase-separated domains is obtained ( FIG. 1I ). Although not shown, further steps include processing the semiconductor substrate using the pattern corresponding to the morphology of the microphase-separated domains as a mask, or using the underlayer film 2 and brush layer 4 to which the pattern has been transferred as a mask.

[0255] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0256] The weight-average molecular weights of the polymers shown in Synthesis Example 1 and Comparative Synthesis Example 1 below in this specification are the results of measurement by gel permeation chromatography (hereinafter abbreviated as GPC). A GPC device manufactured by Tosoh Corporation was used for the measurement, and the measurement conditions were as follows: GPC column: Shodex KF803L, Shodex (registered trademark) KF802, Shodex (registered trademark) KF801 (Showa Denko K.K.) Column temperature: 40°C Solvent: N,N-dimethylformamide (DMF) Flow rate: 0.6 ml / min Standard sample: polystyrene (manufactured by Tosoh Corporation)

[0257] Synthesis Example 1 2.12 g of 2-vinylnaphthalene (60% by molar ratio to the total polymer 1), 1.09 g of 3-hydroxy-1-methacryloyloxyadamantane (20% by molar ratio to the total polymer 1), 0.60 g of 2-hydroxyethyl methacrylate (20% by molar ratio to the total polymer 1), and 0.19 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover polymer 1. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 8,100. The structure present in polymer 1 is shown in the following formula.

[0258]

[0259] Synthesis Example 2 2.13 g of 2-vinylnaphthalene (60% by molar ratio to the total polymer 2), 1.09 g of 3-hydroxy-1-methacryloyloxyadamantane (20% by molar ratio to the total polymer 2), 0.66 g of 2-hydroxypropyl methacrylate (20% by molar ratio to the total polymer 2), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover polymer 2. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 7,100. The structure present in polymer 2 is shown in the following formula.

[0260]

[0261] Synthesis Example 3 1.92 g of 2-vinylnaphthalene (60% by molar ratio to the total mass of Polymer 3), 1.96 g of 3-hydroxy-1-methacryloyloxyadamantane (40% by molar ratio to the total mass of Polymer 3), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction liquid was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 3. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 8,900. The structure present in Polymer 3 is shown in the following formula.

[0262]

[0263] Synthesis Example 4 1.96 g of 4-tert-butylstyrene (60% by molar ratio to the total mass of Polymer 4), 1.93 g of 3-hydroxy-1-methacryloyloxyadamantane (40% by molar ratio to the total mass of Polymer 4), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction liquid was added dropwise to heptane, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 4. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 6,600. The structure present in Polymer 4 is shown in the following formula.

[0264]

[0265] Synthesis Example 5 1.88 g of 2-vinylnaphthalene (molar ratio to the total of Polymer 5: 55%), 1.01 g of benzyl methacrylate (molar ratio to the total of Polymer 5: 26%), 0.99 g of 3-hydroxy-1-methacryloyloxyadamantane (molar ratio to the total of Polymer 5: 19%), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 5. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 7,700. The structure present in Polymer 5 is shown in the following formula.

[0266]

[0267] Synthesis Example 6 1.84 g of 2-vinylnaphthalene (molar ratio to the total mass of Polymer 6: 55%), 1.07 g of 2-phenylethyl methacrylate (molar ratio to the total mass of Polymer 6: 26%), 0.97 g of 3-hydroxy-1-methacryloyloxyadamantane (molar ratio to the total mass of Polymer 6: 19%), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 6. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 7,600. The structure present in Polymer 6 is shown in the following formula.

[0268]

[0269] Synthesis Example 7 1.92 g of 2-vinylnaphthalene (molar ratio to the total of Polymer 7: 55%), 0.95 g of phenyl methacrylate (molar ratio to the total of Polymer 7: 26%), 1.01 g of 3-hydroxy-1-methacryloyloxyadamantane (molar ratio to the total of Polymer 7: 19%), and 0.12 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 7. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 6,800. The structure present in Polymer 7 is shown in the following formula.

[0270]

[0271] Comparative Synthesis Example 1 2.17 g of 2-vinylnaphthalene (60% by molar ratio relative to the total mass of Polymer 8), 1.03 g of 1-adamantyl methacrylate (20% by molar ratio relative to the total mass of Polymer 8), 0.61 g of 2-hydroxyethyl methacrylate (20% by molar ratio relative to the total mass of Polymer 8), and 0.19 g of 2,2'-azobisisobutyronitrile were added to 16.00 g of propylene glycol monomethyl ether acetate and dissolved to obtain a solution. This solution was heated and stirred at 145°C for approximately 3 hours. The resulting reaction solution was added dropwise to 2-propanol, and the precipitate was recovered by suction filtration and then dried under reduced pressure at 60°C to recover Polymer 8. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 7,100. The structure present in Polymer 8 is shown in the following formula.

[0272]

[0273] (Preparation of Underlayer Film-Forming Composition) (Example) The polymers, crosslinking agents, curing catalysts, and solvents obtained in Synthesis Examples 1 to 7 and Comparative Synthesis Example 1 above were mixed in the proportions shown in Table 1, and filtered through a 0.02 μm fluororesin filter to prepare compositions for forming underlayer films for self-assembled monolayers. The abbreviations in Tables 1 and 2 are as follows. The amount of each additive is shown in parts by mass. PL-LI: tetramethoxymethylglycoluril (manufactured by Nippon Cytec Industries Co., Ltd.) PyPTS: pyridinium-p-toluenesulfonic acid PGMEA: propylene glycol monomethyl ether acetate PGME: propylene glycol monomethyl ether

[0274]

[0275]

[0276] (Elution test in photoresist solvent) The compositions for forming underlayer films for self-assembled monolayers of Examples 1 to 7 and Comparative Example 1 were applied to silicon wafers using a spinner. The silicon wafers were baked on a hot plate at 240°C for 60 seconds to obtain films with a thickness of 8 nm. These underlayer films were immersed in a mixed solution of propylene glycol monomethyl ether (PGME) / propylene glycol monomethyl ether acetate (PGMEA) = 70 / 30, which is a solvent used in photoresists, and a change in film thickness of 2 Å or less was rated as "good" and a change in film thickness of more than 2 Å was rated as "poor". The results are shown in Table 3.

[0277] (Film Formability Test) The compositions for forming underlayer films for self-assembled monolayers of Examples 1 to 7 and Comparative Example 1 were applied to silicon wafers using a spinner. The silicon wafers were baked on a hot plate at 240°C for 60 seconds to obtain films with a thickness of 8 nm. The surface roughness (Sa) of these underlayer films was measured using an atomic force microscope (AFM), and a roughness of 3 Å or less was rated as "good" and a roughness of more than 3 Å was rated as "poor." The results are shown in Table 3.

[0278]

[0279] (Evaluation of self-assembly on compositions for forming underlayer films for self-assembled films) Each composition for forming an underlayer film for a self-assembled film was applied to a silicon wafer using a spinner. The silicon wafer was baked on a hot plate at 240°C for 60 seconds to obtain an underlayer film with a thickness of 8 nm. A self-assembled film (block copolymer) solution was spin-coated on the underlayer film and heated at 90°C for 60 seconds to form a self-assembled film. The laminated film was then heated at 90°C for 60 seconds to form a self-assembled film. ２ The sample was baked at 260°C for 900 seconds on a hot plate under atmospheric pressure to promote self-organization (microphase separation). The microphase-separated structure was then observed using a scanning electron microscope (CG4100, manufactured by Hitachi High-Technologies Corporation) to evaluate the vertical alignment. The vertical alignment was evaluated as "good" when the pattern obtained by self-organization was a hole shape (cylinder), and as "poor" when the pattern was a fingerprint-like pattern (fingerprint). The results are shown in Table 4.

[0280]

[0281] (Observation of Microphase Separation Structure) With regard to the alignment of the block copolymer, SEM images of the microphase separation structure of Examples 1 to 7 and Comparative Example 1 are shown in FIGS. 2 to 8 (good vertical alignment) and FIG. 9 (poor vertical alignment), respectively.

[0282] REFERENCE SIGNS LIST 1 semiconductor substrate 2 underlayer film 3 resist film 4 brush layer 5 self-assembled film 5a domain of A block 5b domain of B block

Claims

1. A composition for forming an underlayer film for forming an underlayer film of a self-assembled film, comprising a polymer, the polymer having a unit structure (A) having an alicyclic hydrocarbon group having a reactive group.

2. The composition for forming an underlayer film according to claim 1, wherein the unit structure (A) is a unit structure represented by the following formula (A-1): (In formula (A-1), R １ represents a hydrogen atom or a methyl group. １ represents a single bond, an ester group or an amide group. １ represents a single bond or an alkylene group having 1 to 6 carbon atoms. Cy represents an alicyclic hydrocarbon group having a reactive group.

3. The composition for forming an underlayer film according to claim 1, wherein the polymer further has a unit structure represented by the following formula (B-1): (In formula (B-1), R １１ represents a hydrogen atom or a methyl group. １１ represents an optionally substituted aromatic group.

4. In the formula (B-1), Ar １１ represents optionally substituted naphthalene, anthracene, phenanthrene, pyrene, triphenylene, chrysene, naphthacene, biphenylene, fluorene, or carbazole, or represents benzene having one or more hydrocarbon groups having 1 to 6 carbon atoms as a substituent.

5. The composition for forming an underlayer film according to claim 1, wherein the polymer further has a unit structure (C) having a monocyclic aromatic structure.

6. The composition for forming an underlayer film according to claim 5, wherein the unit structure (C) is a unit structure represented by the following formula (C-1): (In formula (C-1), R ２１ represents a hydrogen atom or a methyl group. ２１ represents an ester group or an amide group. ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. ２１ represents a single bond or an ether group. ２１ R represents optionally substituted benzene, naphthalene or anthracene. ２２ represents a halogen atom or an organic group having 1 to 10 carbon atoms which may be substituted. n represents an integer of 0 to 5. ２２ When there are two or more, there are two or more R ２２ may be the same or different.) 7. The composition for forming an underlayer film according to claim 1, wherein the polymer further has a unit structure (D) having a hydrocarbon group (excluding alicyclic hydrocarbon groups) having a reactive group.

8. The composition for forming an underlayer film according to claim 7, wherein the unit structure (D) is a unit structure represented by the following formula (D-1): (In formula (D-1), R ３１ represents a hydrogen atom or a methyl group. ３１ represents an ester group or an amide group. ３２ represents a hydrocarbon group having 1 to 12 carbon atoms (excluding alicyclic hydrocarbon groups) having a reactive group.

9. The composition for forming an underlayer film according to claim 1, wherein the molar ratio of the unit structure (A) to all unit structures of the polymer is less than 60 mol %.

10. The composition for forming an underlayer film according to claim 3, wherein the molar ratio of the unit structure (B-1) to all unit structures of the polymer is 45 mol % to 80 mol %.

11. The underlayer film forming composition according to claim 1, further comprising a crosslinking agent, the content of said crosslinking agent being 20% ​​by mass to 50% by mass of said polymer.

12. The underlayer film forming composition according to claim 1, wherein the self-assembled film is a film containing a block copolymer.

13. The composition for forming an underlayer film according to claim 1, which is a composition for forming an underlayer film which is used as an underlayer film for a resist film, either a photoresist film or an electron beam resist film, in lithography using the self-assembled film and the resist film, and which is then used as an underlayer film for the self-assembled film.

14. An underlayer film, which is a fired product of a coating film of the composition for forming an underlayer film according to any one of claims 1 to 13.

15. The underlayer film of claim 14, wherein the underlayer film has a thickness of less than 10 nm.

16. A method for manufacturing a semiconductor device, comprising: a step of forming an underlayer film on a semiconductor substrate using a composition for forming an underlayer film according to any one of claims 1 to 13; and a step of forming a self-assembled film on the underlayer film.

17. The method for manufacturing a semiconductor device according to claim 16, wherein in the step of forming the self-assembled film, the self-assembled film is formed on a patterned underlayer film, and further comprising the steps of: forming a resist film, which is either a photoresist film or an electron beam resist film, on the underlayer film; irradiating the resist film with light or an electron beam, and then developing the resist film to obtain a resist pattern; and etching the underlayer film using the resist pattern as a mask to form the patterned underlayer film.

18. The method for manufacturing a semiconductor element according to claim 17, further comprising the step of forming a brush layer in gaps in the pattern of the patterned underlayer film between the step of forming the patterned underlayer film and the step of forming the self-assembled film.

19. The method for producing a semiconductor device according to claim 16, wherein the self-assembled film is a film containing a block copolymer.

20. The method for manufacturing a semiconductor device according to claim 17, further comprising the step of removing the resist pattern after the step of forming the patterned underlayer film.

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