Brush material for self-assembled film

Abstract

Provided is a composition for brush formation that is used in order to induce phase separation of a block copolymer contained in a layer formed on a substrate, the composition containing a brush polymer, an organic base, and a solvent.

Description

Brush materials for self-assembled monolayers

[0001] The present invention relates to a brush-forming composition for forming a fine phase-separated pattern, a method for producing a phase-separated pattern of a block copolymer using the brush-forming composition, and a method for producing a semiconductor device.

[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 primer containing a resin component in which 20 mol % to 80 mol % of the constituent units of the entire component are constituent units derived from aromatic ring-containing monomers.

[0004] Patent Document 2 discloses an underlayer film-forming composition for 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.

[0005] International Publication No. 2012 / 036121 Pamphlet International Publication No. 2014 / 097993 Pamphlet

[0006] When these primers or underlayer film-forming compositions (hereinafter sometimes referred to as "brush-forming compositions") are applied to a substrate to form an underlayer film, the precursor film of the underlayer film is exposed to a solvent to remove film components (e.g., polymers) that have weak adhesion to the substrate. This is because if film components with weak adhesion remain in the underlayer film, the underlayer film will mix with the self-assembled film. Note that if there are many film components with weak adhesion to the substrate, the thickness of the underlayer film after exposure to the solvent will be thin. On the other hand, if the thickness of the underlayer film formed from the brush-forming composition is thin, its function as an underlayer film will be insufficient. Therefore, an underlayer film that is thick even when exposed to a solvent is required.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a brush-forming composition that can form a thick underlayer film even when exposed to a solvent. It is also an object of the present invention to provide a method for producing a phase-separated pattern of a block copolymer and a method for producing a semiconductor device using the brush-forming composition.

[0008] The present inventors conducted extensive research to solve the above-mentioned problems, and as a result, they discovered that by incorporating an organic base into a brush-forming composition, the thickness of the underlayer film after exposure to a solvent can be increased compared to a case where the organic base is not incorporated, and completed the present invention, which has the following gist. That is, the present invention encompasses the following: [1] A brush-forming composition used to phase-separate a block copolymer in a layer containing the block copolymer formed on a substrate, the brush-forming composition comprising a brush polymer, an organic base, and a solvent. [2] The brush-forming composition according to [1], in which the organic base has a nitrogen atom. [3] The brush-forming composition according to [1] or [2], in which the organic base has a nitrogen-containing ring. [4] The brush-forming composition according to any one of [1] to [3], in which the organic base is at least one of N-methylmorpholine, N,N-dimethyl-4-aminopyridine, and diazabicycloundecene. [5] The brush-forming composition according to any one of [1] to [4], wherein the content of the organic base is 0.1% by mass to 30% by mass relative to the brush polymer. [6] The brush-forming composition according to any one of [1] to [5], wherein the content of the organic base is 0.5% by mass to 15% by mass relative to the brush polymer. [7] The brush-forming composition according to any one of [1] to [6], wherein the brush polymer has a functional group capable of bonding to the substrate. [8] The brush-forming composition according to [7], wherein the functional group capable of bonding to the substrate is a hydroxy group, an amino group, or a sulfonic acid group. [9] The brush-forming composition according to any one of [1] to [8], wherein the brush polymer is an addition polymerization type polymer.

[10] The brush-forming composition according to any one of [1] to [9], wherein the brush-forming composition is an underlayer film-forming composition for forming an underlayer film for a layer containing the block copolymer.

[11] A substrate with an underlayer film, obtained by applying the brush-forming composition according to any one of [1] to

[10] onto a substrate, heating the composition, and exposing the resulting precursor film to a solvent.

[12] A method for manufacturing a substrate having a phase-separated pattern of a block copolymer, comprising: (1) a step of forming an underlayer film on a substrate using the brush-forming composition according to any one of [1] to

[10] , (2) a step of forming a layer containing a block copolymer on the underlayer film, and (3) a step of phase-separating the block copolymer.

[13] The manufacturing method according to

[12] , further comprising a step of forming an overlayer film on the layer containing the block copolymer between steps (2) and (3).

[14] The manufacturing method according to

[12] or

[13] , wherein step (1) comprises: a process of applying the brush-forming composition onto the substrate, a process of heating the brush-forming composition applied to the substrate to form a precursor film of the underlayer film, and a process of exposing the precursor film of the underlayer film to a solvent to obtain the underlayer film.

[15] A method for manufacturing a semiconductor device, comprising: (1) a step of forming an underlayer film on a substrate using the brush-forming composition according to any one of [1] to

[10] , (2) a step of forming a layer containing a block copolymer on the underlayer film, (3) a step of phase-separating the block copolymer, (4) a step of removing a portion of the phase-separated block copolymer, and (5) a step of etching the substrate.

[16] The manufacturing method according to

[15] , further comprising a step of forming an overlayer film on the layer containing the block copolymer between the steps (2) and (3).

[17] The manufacturing method according to

[15] or

[16] , wherein the step (1) comprises: a treatment of applying the brush-forming composition onto the substrate, a treatment of heating the brush-forming composition applied to the substrate to form a precursor film of the underlayer film, and a treatment of exposing the precursor film of the underlayer film to a solvent to obtain the underlayer film.

[0009] The present invention provides a brush-forming composition that can form a thick underlayer film even when exposed to a solvent. Another object of the present invention is to provide a method for producing a phase-separated pattern of a block copolymer and a method for producing a semiconductor device using the brush-forming composition.

[0010] (Brush-forming composition) The brush-forming composition of one embodiment of the present invention contains a brush polymer, an organic base, and a solvent, and may further contain other components as necessary. The brush-forming composition is used to cause phase separation of the block copolymer in a layer containing the block copolymer formed on a substrate. A film formed from the brush-forming composition is used as an underlayer film to cause phase separation of the block copolymer in a layer containing the block copolymer formed on a substrate.

[0011] The brush-forming composition is, for example, a composition containing polymer chains capable of directly bonding to the substrate surface. A film or layer in which polymer chains are arranged in a brush-like pattern on a substrate is sometimes called a brush layer. The brush-forming composition is, for example, a composition for forming an underlayer film for forming an underlayer film for a layer containing a block copolymer. Furthermore, a film formed from the brush-forming composition serves, for example, as a guide that controls the position of occurrence of a polymer phase formed by self-assembly. For example, a film formed from the brush-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-forming composition is a chemical guide (chemical-epitaxy) that is formed on an underlayer of a self-assembling material and controls the position of formation of a microphase-separated pattern based on the difference in surface energy.

[0012] <Organic Base> When the brush-forming composition contains an organic base, when the precursor film of the underlayer film obtained from the brush-forming composition is exposed to a solvent and then the underlayer film is formed, a thicker film can be obtained compared to when the brush-forming composition does not contain an organic base. In other words, a thick underlayer film can be obtained even when exposed to a solvent.

[0013] The atoms constituting the organic base are not particularly limited, and the organic base has, for example, a nitrogen atom. Examples of the atoms constituting the organic base include a carbon atom, an oxygen atom, a nitrogen atom, and an oxygen atom.

[0014] The organic base is, for example, an organic compound whose conjugate acid has a pKa of 6-50.

[0015] The organic base may or may not be a salt. The molecular weight of the organic base is not particularly limited, but may be, for example, 40 to 500. The organic base is, for example, a liquid or solid at 25°C.

[0016] The organic base may or may not have a nitrogen-containing ring, for example. The number of nitrogen atoms in the nitrogen-containing ring may be one, two, or three or more, but one or two is preferred. The nitrogen-containing ring has a nitrogen atom and a carbon atom as ring-constituting atoms, and may further have an oxygen atom. Here, the atoms constituting the ring refer to atoms that directly contribute to the ring structure. Taking morpholine as an example, one nitrogen atom, one oxygen atom, and four carbon atoms correspond to the atoms constituting the ring of morpholine, and hydrogen atoms do not qualify as ring-constituting atoms. The nitrogen-containing ring may or may not have a double bond. When the nitrogen-containing ring has a double bond, the double bond may be a carbon-carbon double bond or a carbon-nitrogen double bond. When the nitrogen-containing ring has a double bond, the number of double bonds is not particularly limited, and examples include one to three double bonds.

[0017] Examples of the organic base include compounds represented by the following formulas (I) to (V) and nitrogen-containing polycyclic compounds. [In formula (I), R １ ~R ３ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms. １ ~R ３ At least one of R is a group other than a hydrogen atom. ２ and R ３ may form a ring structure together with N. ２ and R ３ R, except when R is taken together with N to form a ring structure １ ~R ３In formula (II), the methylene group of the alkyl group having 1 to 6 carbon atoms and the hydroxyalkyl group having 1 to 6 carbon atoms may be substituted with —O—. １１ ~R １４ X each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. － represents a halogen anion or a hydroxy anion. ２１ ~R ２４ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms. L is an alkylene group having 1 to 5 carbon atoms. In formula (IV), Y is NR ３２ , O, or S. ３１ and R ３２ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms, or an alkyl sulfonate group having 1 to 4 carbon atoms. ４１ ~R ４３ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or —N(R ５１ ) (R ５２ ) (R ５１ and R ５２ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0018] Examples of compounds represented by formula (I) include the following compounds: (I-1) Primary amines: propylamine, butylamine, pentylamine, 2-methylbutylamine, 2-aminoethanol, 3-amino-1-propanol, aminoethoxyethanol, cyclohexylamine, cyclopentylamine (I-2) Secondary amines: diethylamine, dipropylamine, dibutylamine, dimethanolamine, diethanolamine, piperidine, pyrrolidine (I-3) Tertiary amines: triethylamine, tripropylamine, N-methyldiethylamine, trimethanolamine, triethanolamine

[0019] Examples of the compound represented by formula (II) include the following compounds: Tetramethylammonium hydroxide Triethylmethylammonium hydroxide Tetraethylammonium hydroxide Tetrapropylammonium hydroxide Tetrabutylammonium hydroxide Tetrabutylammonium fluoride Tetrabutylammonium chloride Tetrabutylammonium bromide Tetrabutylammonium iodide Tetrahexylammonium hydroxide Hexadecyltrimethylammonium hydroxide Choline Benzyltrimethylammonium hydroxide Benzyltriethylammonium hydroxide Tris(2-hydroxyethyl)methylammonium hydroxide

[0020] Examples of the compound represented by formula (III) include the following compounds: - Ethylenediamine - 1,2-Diaminopropane - 1,3-Diaminopropane - N,N,N',N'-Tetramethylethylenediamine - N,N,N',N'-Tetraethylethylenediamine - N,N,N',N'-Tetrapropylethylenediamine - N,N,N',N'-Tetraisopropylethylenediamine - N,N,N',N'-Tetrabutylethylenediamine - N,N,N',N'-Tetraisobutylethylenediamine - N,N,N',N'-Tetramethyl-1,2-propylenediamine - N,N,N',N'-Tetraethyl-1,2-propylenediamine - N,N,N',N'-Tetrapropyl-1,2-propylenediamine - N,N,N',N'-Tetraisopropyl-1,2-propylenediamine - N,N,N',N'-Tetramethyl-1,3-propylenediamine・N,N,N',N'-Tetraethyl-1,3-propylenediamine ・N,N,N',N'-Tetrapropyl-1,3-propylenediamine ・N,N,N',N'-Tetraisopropyl-1,3-propylenediamine ・N,N,N',N'-Tetraisobutyl-1,3-propylenediamine ・N,N,N',N'-Tetramethyl-1,2-butylenediamine ・N,N,N',N'-Tetraethyl-1,2-butylenediamine ・N,N-Dimethylaminoethylamine ・N,N-Diethylaminoethylamine ・N,N-Dimethylaminopropylamine ・N,N-Diethylaminopropylamine ・N-Methylaminoethylamine ・N-Ethylaminoethylamine ・N-(2-aminoethylamino)ethanol

[0021] Examples of the compound represented by formula (IV) include piperazine, 1-methylpiperazine, N,N'-dimethylpiperazine, 1-ethylpiperazine, N,N'-diethylpiperazine, 1-(2-hydroxyethyl)piperazine, 1,4-bis(2-hydroxyethyl)piperazine, N-(2-aminoethyl)piperazine, 1,4-bis(2-aminoethyl)piperazine, 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid, piperazine-1,4-bis(2-ethanesulfonic acid), morpholine, 4-methylmorpholine, 4-ethylmorpholine, 4-(2-aminoethyl)morpholine, 4-(2-hydroxyethyl)morpholine, 2-morpholinoethanesulfonic acid, and 3-morpholinopropanesulfonic acid.

[0022] Examples of the compound represented by formula (V) include pyridine, collidine, lutidine, 2-aminopyridine, 4-aminopyridine, 2,6-diaminopyridine, N,N-dimethyl-4-aminopyridine, and N,N-diethyl-4-aminopyridine.

[0023] The nitrogen-containing polycyclic compound is not particularly limited as long as it is a polycyclic compound having a nitrogen atom, and examples thereof include 1,8-diazabicyclo[5.4.0]undecene-7 (diazabicycloundecene, DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5,7-triazabicyclo[4.4.0]decene-5 (TBD), and 7-methyl-1,5,7-triazabicyclo[4.4.0]decene-5 (MTBD).

[0024] The content of the organic base in the brush-forming composition is not particularly limited, but from the viewpoint of suitably obtaining the effects of the present invention, it is preferably 0.1% by mass to 30% by mass, more preferably 0.3% by mass to 25% by mass, and particularly preferably 0.5% by mass to 15% by mass, relative to the brush polymer.

[0025] <Brush Polymer> The brush polymer is not particularly limited as long as it is a brush polymer used in forming the underlayer film.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The brush polymer is preferably an addition polymerization type polymer obtained by, for example, polymerizing one or more radically polymerizable monomers.

[0038] 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.

[0039] <<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.

[0040] 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.

[0041] 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.

[0042] The polymer (P) is, for example, a random copolymer.

[0043] The polymer (P) may contain structural units other than the structural units (A) and (B).

[0044] 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-.

[0045] 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.

[0046] The structural unit (A) is a structural unit different from the structural unit (B), and therefore, the structural unit (A) does not have an aromatic ring.

[0047] The structural unit (A) in the polymer (P) may be of one type or of two or more types.

[0048] The structural unit (A) preferably contains a structural unit (A-1) represented by the following formula (1). (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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] Examples of the (meth)acrylic compound include compounds represented by the following formula (1-1). (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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] Examples of sulfonic acid group-containing (meth)acrylates include 2-sulfoethyl (meth)acrylate and 3-sulfopropyl (meth)acrylate.

[0058] Examples of hydroxy group-containing (meth)acrylamides include N-(hydroxymethyl)(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and N-(4-hydroxybutyl)(meth)acrylamide.

[0059] 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.

[0060] 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.

[0061] The structural unit (B) in the polymer (P) may be of one type or of two or more types.

[0062] The structural unit (B) preferably includes a structural unit (B-1) represented by the following formula (2): The structural unit (B) preferably includes a structural unit (B-2) represented by the following formula (3): (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.) (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.

[0063] 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-.

[0064] 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%.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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). (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.) (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.

[0070] 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.

[0071] <<Method for Producing Brush Polymers>> The method for producing brush polymers 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, desired monomers can be added to a solvent to which a polymerization initiator has been added to polymerize. 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.

[0072] 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.

[0073] <<<Polymerization Initiator>>> As the polymerization initiator, an organic peroxide or a diazo compound can be used.

[0074] 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.

[0075] 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).

[0076] 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.

[0077] 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.

[0078] <<<<Solvent>>> The solvent used in the polymerization is not particularly limited as long as it is inert to the polymerization reaction and is 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.

[0079] 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.

[0080] <Solvent> The solvent contained in the brush-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.

[0081] The content of the solvent in the brush-forming composition is not particularly limited, but is, for example, 90% by mass or more and 99.9% by mass or less.

[0082] <Other Components> The brush-forming composition preferably does not contain a crosslinking agent. In the present invention, by reacting the brush polymer with the substrate, the film obtained from the brush-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-forming composition does not need to contain a crosslinking agent. In the present invention, "not containing a crosslinking agent" can also include the presence 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-forming composition does not contain a crosslinking agent, the content of the crosslinking agent in the brush-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.

[0083] Examples of the crosslinking agent include nitrogen-containing compounds having 2 to 4 nitrogen atoms substituted with methylol groups or alkoxymethyl groups.

[0084] 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.

[0085] The brush-forming composition may contain a surfactant. The surfactant is an additive for improving the coating properties on 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-forming composition is, for example, 0.1% by mass to 5% by mass relative to the brush polymer.

[0086] In the brush-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-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.

[0087] The method for preparing the brush-forming composition is not particularly limited. For example, the brush-forming composition can be obtained by dissolving the brush polymer and additives added as needed in an appropriate solvent. After dissolving the brush polymer and additives added as needed in the solvent, it is preferable to filter the resulting composition through a microfilter, and more preferably, after dissolving in the solvent, it is preferable to filter the resulting composition through a microfilter with a pore size of 0.2 μm or less.

[0088] Furthermore, another embodiment of the brush-forming composition of the present invention may be a composition (x) that has low adhesion to an underlayer film (x) for inducing self-assembly of an upper-layer block copolymer, and is used in combination with the brush-forming composition of one embodiment of the present invention, but is different from the brush-forming composition of one embodiment of the present invention. The term "low adhesion" means that the thickness of the film adhered to the underlayer film (x), as evaluated by the method described in the Examples, is 20 nm or less, 10 nm or less, 5 nm or less, or 3 nm or less. The film-forming conditions for the underlayer film (x) are baking at 200 to 300°C (e.g., 240°C or 250°C) for 0.5 to 3 minutes (e.g., 1 minute).

[0089] The composition (x) may be an underlayer film-forming composition described in WO 2018 / 135455 pamphlet, which is used to phase-separate a layer containing a block copolymer formed on a substrate, the composition comprising a copolymer represented by the following formula: (A) a unit structure derived from a styrene compound containing a tert-butyl group, (B) a unit structure derived from an aromatic-containing vinyl compound that does not contain a hydroxy group, the unit structure being other than (A), (C) a unit structure derived from a compound that contains a (meth)acryloyl group and does not contain a hydroxy group, and (D) a unit structure derived from a cross-linking group-containing compound, wherein the copolymerization ratios of the units relative to the entire copolymer are (A) 25 to 90 mol %, (B) 0 to 65 mol %, (C) 0 to 65 mol %, and (D) 10 to 20 mol %, and the aromatic-containing unit structure accounts for 81 to 90 mol % of (A) + (B) + (C). The composition may be a composition (x) in which the unit structure (A) derived from the styrene compound containing a tert-butyl group is represented by formula (1). (In formula (1), R １ From R ３ One or two of the groups are tert-butyl groups.)

[0090] The unit structure (D) derived from the crosslinking group-containing compound may be a unit structure represented by formula (2-1), (2-2), (3-1) or (3-2). (In formulas (2-1) and (2-2), n Xs each independently represent a hydroxy group, a halogen atom, an alkyl group, an alkoxy group, a cyano group, an amide group, an alkoxycarbonyl group, or a thioalkyl group, and n represents an integer of 1 to 7.) (In formulas (3-1) and (3-2), R ４ represents a hydrogen atom or a methyl group, R ５ represents a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms which has a hydroxy group and may be substituted with a halogen atom, or a hydroxyphenyl group.

[0091] The unit structure (B) derived from the aromatic-containing vinyl compound not containing a hydroxy group and other than the unit structure (A) may be a unit structure represented by formula (4-1) or (4-2). (In formulas (4-1) and (4-2), n Ys each independently represent a halogen atom, an alkyl group, an alkoxy group, a cyano group, an amide group, an alkoxycarbonyl group, or a thioalkyl group, and n represents an integer of 0 to 7.)

[0092] The unit structure (C) derived from a compound containing a (meth)acryloyl group but not a hydroxy group may be a unit structure represented by formula (5-1) or (5-2). (In formulas (5-1) and (5-2), R ９ represents a hydrogen atom or a methyl group, R １０ each independently represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a benzyl group, or an anthrylmethyl group.) The contents of WO2018 / 135455 are incorporated herein by reference to the same extent as if fully set forth herein.

[0093] The composition (x) may contain a polymer (X-1) having a unit structure derived from an aromatic compound, as described in WO 2022 / 039187. The aromatic compound preferably contains an aryl group having 6 to 40 carbon atoms.

[0094] Examples of the aryl group having 6 to 40 carbon atoms include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, an o-chlorophenyl group, an m-chlorophenyl group, a p-chlorophenyl group, an o-fluorophenyl group, a p-fluorophenyl group, an o-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, a p-cyanophenyl group, an α-naphthyl group, a β-naphthyl group, an o-biphenylyl group, an m-biphenylyl group, a p-biphenylyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group. Among these, it is preferable that the aromatic compound contains a phenyl group, an α-naphthyl group (=1-naphthyl group), or a β-naphthyl group (=2-naphthyl group). The α-naphthyl group (=1-naphthyl group) or β-naphthyl group (=2-naphthyl group) is preferably contained in an amount of 40 mol % or more, 45 mol % or more, 50 mol % or more, 60 mol % or more, 70 mol % or more, or 80 mol % or more relative to the entire polymer (X-1). The upper limit is, for example, 95 mol % or 90 mol %.

[0095] The polymer (X-1) may be, for example, a polymer derived from 1-vinylnaphthalene, 2-vinylnaphthalene or benzyl methacrylate, preferably a polymer derived from 2-vinylnaphthalene or benzyl methacrylate.

[0096] The polymer (X-1) preferably contains 50 mol% or more of the aromatic compound-derived unit structures relative to all the unit structures of the polymer (X-1). More preferably, the polymer (X-1) contains, for example, 50 mol% to 99 mol%, 55 mol% to 99 mol%, 60 mol% to 99 mol%, 65 mol% to 99 mol%, 70 mol% to 99 mol%, 75 mol% to 99 mol%, 80 mol% to 99 mol%, 81 mol% to 99 mol%, 82 mol% to 98 mol%, 83 mol% to 97 mol%, 84 mol% to 96 mol%, or 85 mol% to 95 mol% of the aromatic compound-derived unit structures relative to all the unit structures of the polymer (X-1).

[0097] Furthermore, the composition (x) may be a composition for forming an underlayer film of a self-assembled film, characterized in that it contains a polymer (X-2) having 0.2 mol% or more of unit structures of a polycyclic aromatic vinyl compound per total unit structures of the polymer, as described in WO2014 / 097993.

[0098] The polymer (X-2) may be a polymer (X-2) having 20 mol % or more of unit structures of an aromatic vinyl compound per all unit structures of the polymer (X-2), and having 1 mol % or more of unit structures of a polycyclic aromatic vinyl compound per all unit structures of the aromatic vinyl compound. The aromatic vinyl compound may include vinylnaphthalene, acenaphthylene, or vinylcarbazole, each of which may be substituted, and the polycyclic aromatic vinyl compound may be vinylnaphthalene, acenaphthylene, or vinylcarbazole. The aromatic vinyl compound may include styrene, which may be substituted, and vinylnaphthalene, acenaphthylene, or vinylcarbazole, each of which may be substituted, and the polycyclic aromatic vinyl compound may be vinylnaphthalene, acenaphthylene, or vinylcarbazole. The aromatic vinyl compound may be an optionally substituted styrene and an optionally substituted vinylnaphthalene, acenaphthylene, or vinylcarbazole, and the polycyclic aromatic vinyl compound may be an optionally substituted vinylnaphthalene, acenaphthylene, or vinylcarbazole. The aromatic vinyl compound may consist solely of a polycyclic aromatic vinyl compound, and the aromatic vinyl compound may be an optionally substituted vinylnaphthalene, acenaphthylene, or vinylcarbazole. The polymer (X-2) may contain 60 to 95 mol% of aromatic vinyl compound unit structures per total unit structure of the polymer (X-2). The polymer (X-2) may further contain a unit structure having a crosslinking group. The crosslinking group may be a hydroxy group, an epoxy group, a protected hydroxy group, or a protected carboxyl group. Specific examples of the polymer (X-2) are shown below. (The structure of formula (1-10-1) is an example of the polymer terminal structure of formula (1-10).) The contents of WO2014 / 097993 are incorporated herein by reference to the same extent as if fully set forth herein.

[0099] (Substrate with Underlayer Film) The substrate with underlayer film of the present invention is obtained by applying the brush-forming composition of the present invention to a substrate, heating the composition, and exposing the resulting precursor film of the underlayer film to a solvent. Examples of a method for producing a substrate with an underlayer film include the following step (1).

[0100] (Method for manufacturing a substrate having a phase-separated pattern of a block copolymer) The method for manufacturing a substrate having a phase-separated pattern of a block copolymer of the present invention includes the following steps (1) to (3): Step (1): A step of forming an underlayer film on a substrate using the brush-forming composition of the present invention; Step (2): A step of forming a layer containing a block copolymer on the underlayer film; and Step (3): A step of phase-separating the block copolymer.

[0101] Furthermore, the method for producing a substrate having a phase-separated pattern of a block copolymer preferably includes, between steps (2) and (3), a step of forming an upper layer film on the layer containing the block copolymer.

[0102] <Step (1)> Step (1) is a step of forming an underlayer film on a substrate using the brush-forming composition of the present invention. The underlayer film is formed on the substrate to obtain neutral surface energy.

[0103] The substrate may be, for example, a substrate selected from the group consisting of silicon, silicon oxide, glass, surface-modified glass, plastic, ceramic, transparent substrate, flexible substrate, substrate used in roll-to-roll processing, and combinations thereof. Preferably, the substrate is a silicon wafer, quartz, glass, or plastic, more preferably a silicon wafer. The substrate is typically a silicon wafer, but an SOI (silicon-on-insulator) substrate or a compound semiconductor wafer such as gallium arsenide (GaAs), indium phosphide (InP), or gallium phosphide (GaP) may also be used. A substrate having an insulating film formed thereon, such as a silicon nitride film, a silicon oxide film, a nitrogen-containing silicon oxide film (SiON film), or a carbon-containing silicon oxide film (SiOC film), may also be used. In this case, the brush-forming composition according to the present invention is applied onto the insulating film.

[0104] Furthermore, the substrate before the underlayer film is formed with the brush-forming composition may have a silicon- and organic group-containing film. The silicon- and organic group-containing film is a film formed from a hydrolysis condensate 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 condensate of a hydrolyzable silane containing a compound represented by the following formula (A): (In formula (A), R ａ represents 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.

[0105] 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

[0106] The step (1) preferably includes the following treatments (1-1) to (1-3): (1-1) treatment: a treatment in which the brush-forming composition is applied onto a substrate; (1-2) treatment: a treatment in which the brush-forming composition applied onto the substrate is heated to form a precursor film of the underlayer film; and (1-3) treatment: a treatment in which the precursor film of the underlayer film is exposed to a solvent to obtain the underlayer film.

[0107] In the (1-1) treatment, the brush-forming composition can be applied to the substrate by a conventional method, for example, by a suitable application method such as a spinner or coater.

[0108] In the (1-2) treatment, the brush-forming composition applied to the substrate is heated to form a precursor film for the underlayer film. The heating temperature may be, for example, 80°C to 500°C, 80°C to 350°C, or 150°C to 300°C. The heating time may be, for example, 0.3 minutes to 60 minutes, or 0.5 minutes to 2 minutes. Preferably, the heating temperature is 150°C to 300°C, and the heating time is 0.5 minutes to 2 minutes.

[0109] In the (1-2) treatment, for example, functional groups in the brush polymer capable of bonding to the substrate are bonded to the substrate by heating. The surface of the substrate usually has functional groups such as hydroxyl groups. For example, the surface of a silicon wafer has -Si-OH groups. The surface of a silicon- and organic group-containing film has -Si-OH groups. In the (1-2) treatment, for example, functional groups in the brush polymer capable of bonding to the substrate are bonded to functional groups on the substrate surface by heating. In this way, a precursor film of the underlayer film is obtained on the substrate. The precursor film of the underlayer film has polymer chains bonded to the substrate.

[0110] In the (1-3) treatment, the precursor film of the underlayer film is exposed to a solvent to obtain the underlayer film. The precursor film of the underlayer film contains polymer chains that are not bonded to the substrate. In the (1-3) treatment, by exposing the precursor film of the underlayer film to a solvent, polymer chains that are not bonded to the substrate are removed from the precursor film of the underlayer film, thereby obtaining the underlayer film. In this case, since the brush-forming composition contains an organic base, a thicker underlayer film can be obtained compared to a film that does not contain an organic base. The solvent used is not particularly limited, and examples thereof include solvents used in the brush-forming composition. The method of exposing the precursor film of the underlayer film to a solvent is not particularly limited, and examples thereof include a method of immersing a substrate having a precursor film of the underlayer film in a solvent. The immersion time is not particularly limited.

[0111] The thickness of the underlayer film (after exposure to a solvent) is not particularly limited, but is preferably 2.0 nm to 10.0 nm, more preferably 2.5 nm to 8.0 nm.

[0112] <Step (2)> Step (2) is a step of forming a layer containing a block copolymer on the underlayer film. Hereinafter, the "layer containing a block copolymer" may be referred to as a "block copolymer layer." The block copolymer layer can be formed by a conventional method, for example, by applying a self-assembled film-forming composition containing a block copolymer to the underlayer layer by means of spin coating or the like to a predetermined film thickness, and then baking the applied composition.

[0113] The baking (heating) temperature is not particularly limited and may be, for example, 50° C. to 150° C., 70° C. to 130° C., or 80° C. to 120° C. The baking time is not particularly limited and may be, for example, 1 second to 10 minutes, 10 seconds to 5 minutes, or 30 seconds to 3 minutes.

[0114] The thickness of the layer containing the block copolymer to be formed is not particularly limited, and may be, for example, 5 nm to 200 nm, 10 nm to 130 nm, or 20 nm to 80 nm.

[0115] <<Self-Assembled Film-Forming Composition>> The self-assembled film-forming composition contains a block copolymer. The self-assembled film-forming composition usually contains a solvent.

[0116] 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.

[0117] <<<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).

[0118] 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).

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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): (In formula (1-1c) or formula (1-2c), R １ and R ２each 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.

[0123] The silicon-containing group may contain one silicon atom. The silicon-containing polymer may contain a unit structure represented by the following formula (2c): (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.

[0124] Furthermore, the block copolymer may be one described in JP-T-2019-507815 A, including the following [BCP1] to [BCP4]. The entire disclosure of JP-T-2019-507815 A is incorporated herein by reference. [BCP1] A block copolymer containing 5-vinylbenzo[d][1,3]dioxole. [BCP2] The block copolymer described in [BCP1], wherein the block copolymer further contains a silicon-containing block. [BCP3] The block copolymer described in [BCP2], wherein the block copolymer further contains pentamethyldisilylstyrene. [BCP4] The block copolymer described in [BCP3], wherein the block copolymer is poly(5-vinylbenzo[d][1,3]dioxole)-b-poly(pentamethyldisilylstyrene).

[0125] The synthesis of the above-described poly(5-vinylbenzo[d][1,3]dioxole-block-4-pentamethyldisilylstyrene) is shown in Scheme 1 below. Me represents a methyl group.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] Further examples include block copolymers formed from a combination of the organic polymers and / or metal-containing polymers described below.

[0131] 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.

[0132] Metal-containing polymers include, but are not limited to, silicon-containing polymers such as polydimethylsiloxane (PDMS), polyhedral silsesquioxane (POSS), or poly(trimethylsilylstyrene) (PTMSS) or polymers containing silicon and iron such as poly(ferrocenyldimethylsilane) (PFS).

[0133] Exemplary block copolymers include, but are not limited to, diblock copolymers such as 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 such as 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] Examples of siloxane derivatives include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, methylphenylsiloxane, etc. Examples of alkylene oxides include ethylene oxide, propylene oxide, isopropylene oxide, butylene oxide, etc.

[0138] Examples of the block copolymer include 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.

[0139] <<<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

[0140] 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.

[0141] 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.

[0142] 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).

[0143] 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).

[0144] Two or more low-boiling point solvents (A) and two or more high-boiling point solvents (B) may be selected and mixed for use.

[0145] 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.

[0146] <Step of forming upper layer film> The step of forming an upper layer film is a step between steps (2) and (3) in which an upper layer film is formed on a layer containing a block copolymer. Optionally, an upper layer film is formed on the block copolymer layer obtained above. The formation of the upper layer film can be performed by a well-known method, i.e., by applying an upper layer film-forming composition to the block copolymer layer and baking it.

[0147] The composition for forming an upper layer film is applied onto the block copolymer layer by a conventional means such as spin coating to form an upper layer film. The thickness of the formed upper layer film is not particularly limited, but is generally 3 nm to 100 nm, preferably 10 nm to 70 nm, and particularly preferably 20 nm to 60 nm. The composition for forming an upper layer film is preferably dissolved in a solvent or solvent mixture that does not damage, dissolve, or substantially swell the block copolymer.

[0148] <<Composition for Forming Upper Layer Film>> The composition for forming an upper layer film is a composition used to cause phase separation of the block copolymer in the layer containing the block copolymer. The composition for forming an upper layer film contains, for example, the following components (X) and (Y). Component (X): (x) a copolymer containing a structural unit derived from a maleimide structure and a structural unit derived from a styrene structure. Component (Y): an ether compound having 8 to 16 carbon atoms as a solvent.

[0149] The upper layer film formed from the composition for forming an upper layer film may be formed on a block copolymer layer, and the orientation of the block copolymer may be controlled by heating, and then removed. Even for a block copolymer layer that cannot be oriented by heating alone, orientation is possible by using an upper layer film formed from the present composition.

[0150] <<<Component (X): Copolymer (X)>>> The component (X) is copolymer (X). Copolymer (X) contains structural units derived from a maleimide structure and structural units derived from a styrene structure.

[0151] As used herein, the terms "maleimide structure" and "styrene structure" refer to chemical structures having maleimide and styrene as their skeletons, respectively. The term "structural unit derived therefrom" refers to a repeating unit constituting the main chain of a copolymer, which is derived from a compound having a maleimide structure or a styrene structure while maintaining the skeleton.

[0152] <<<<<(x) Structural Units Derived from a Maleimide Structure and Structural Units Derived from a Styrene Structure>>>> Preferably, the structural unit derived from a maleimide structure is represented by formula (11). (In formula (11), R １１ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom.

[0153] Preferably, the structural unit derived from the styrene structure is represented by formula (12). (In formula (12), R １２ ~R １４ , R １７ and R １８ R each independently represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom. １７ and R １８ is preferably a hydrogen atom.

[0154] The molar ratio of the structural units represented by formula (11) and formula (12) to the entire copolymer (X) is preferably as follows: structural units of formula (11): 30 to 70 mol % structural units of formula (12): 20 to 50 mol % relative to the entire copolymer (X).

[0155] <<<<<Structural Units Derived from (y) (Meth)acrylic Groups>>>> Furthermore, the copolymer (X) can contain structural units derived from (y) (meth)acrylic groups in addition to the formulas (11) and (12).

[0156] Preferably, the structural unit derived from the (meth)acrylic group is represented by formula (13). (In formula (13), R １５ and R １６each independently represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom.

[0157] The molar ratio of the structural unit of formula (13) to the entire copolymer (X) is preferably 0.1 to 50 mol %, more preferably 0.1 to 30 mol %, even more preferably 0.1 to 20 mol %, and most preferably 0.1 to 10 mol %, based on the entire copolymer (X).

[0158] In the above formula (11), examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a benzyl group, and a naphthyl group.

[0159] The distribution of the structural units represented by formulas (11), (12), and (13) in copolymer (X) is not particularly limited. That is, in copolymer (X), the structural units represented by formulas (11) and (12) may be alternately copolymerized or randomly copolymerized. Furthermore, when a structural unit represented by formula (13) is also present, the structural units represented by formulas (11), (12), and (13) in copolymer (X) may each constitute a block or may be randomly bonded.

[0160] The number of repetitions of the structural units represented by formulas (11), (12), and (13) in copolymer (X) can be appropriately selected within the range of the mol% of each structural unit described above, and within the range that allows the weight average molecular weight Mw of copolymer (X) to be 5,000 to 500,000, preferably 10,000 to 100,000.

[0161] <<<<<Method for Producing Copolymer (X)>>>> The method for producing copolymer (X) includes, for example, a step of copolymerizing a monomer mixture containing a compound represented by formula (14) and a compound represented by formula (15). (In formula (14), R ２１ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom. (In formula (15), R ２２ ~R ２４ , R２７ and R ２８ R each independently represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom. ２７ and R ２８ is preferably a hydrogen atom.

[0162] The monomer mixture may optionally contain a compound represented by formula (16). (In formula (16), R ２５ and R ２６ each independently represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom.

[0163] The monomer mixture preferably contains the compounds represented by formula (14) and formula (15) in the following proportions relative to the monomer mixture: Compound represented by formula (14): 30 to 70 mol % Compound represented by formula (15): 20 to 50 mol %

[0164] When the compound represented by formula (16) is contained, the monomer mixture preferably contains the compound represented by formula (14): 30 to 70 mol % The compound represented by formula (15): 20 to 50 mol % The compound represented by formula (16): 0.1 to 40 mol % relative to the monomer mixture.

[0165] Specific examples of the compound represented by formula (14) include the following.

[0166] Specific examples of the compound represented by formula (15) include the following.

[0167] The copolymer (X) can be obtained by a known polymerization method, such as radical polymerization, anionic polymerization, or cationic polymerization. Various known techniques, such as solution polymerization, suspension polymerization, emulsion polymerization, or bulk polymerization, can also be used.

[0168] The polymerization initiator used in the polymerization includes 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(4-methyl ... Examples of compounds that can be used include bis(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.

[0169] Examples of solvents that can be used during polymerization 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.

[0170] The reaction is carried out under stirring conditions of 50° C. to 200° C. for 1 to 48 hours, whereby the copolymer (X) suitable for carrying out the present invention can be obtained.

[0171] The solution containing the copolymer (X) thus obtained can be used as it is for preparing a composition for forming an upper layer film, or the copolymer (X) can be recovered by precipitation and isolation in a poor solvent such as methanol, ethanol, isopropanol, or water, or a mixed solvent thereof, and then used.

[0172] After isolating copolymer (X), it may be redissolved in an ether compound having 8 to 16 carbon atoms as described below and used, or it may be dried before use. When drying, drying conditions are preferably 30 to 100°C for 6 to 48 hours in an oven or the like. After recovering copolymer (X), it is redissolved in an ether compound having 8 to 16 carbon atoms as described below to prepare a composition suitable for carrying out the present invention, which can be used as a composition for forming an upper layer film.

[0173] <<<Component (Y): Solvent>>> The solvent used in the composition for forming an upper layer film is an ether compound having 8 to 16 carbon atoms. More specifically, the ether compound having 8 to 16 carbon atoms (hereinafter, sometimes referred to as an "ether solvent") used as the solvent in the composition for forming an upper layer film is represented by the following formula (6): In formula (6), A １ and A ２ each independently represents an optionally substituted linear, branched or cyclic saturated alkyl group having 1 to 15 carbon atoms.

[0174] Among these, preferred solvents include dibutyl ether, diisobutyl ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, dioctyl ether, and cyclopentyl methyl ether, which have an excellent balance between the solubility of copolymer (X) and the insolubility of the block copolymer suitable for carrying out the present invention, and more preferred solvents are dibutyl ether, diisobutyl ether, and diisoamyl ether, with diisoamyl ether being particularly preferred. These ether solvents can be used alone or as a mixture.

[0175] For convenience of synthesizing the copolymer (X), the following organic solvents may be mixed with the ether solvent. Examples of such solvents include those listed in the section on the production method of the copolymer (X). The solvent other than the above ether solvent may be present in an amount of 0.01 to 13% by mass relative to the above ether solvent.

[0176] <<<Additives>>> The composition for forming the upper layer film may further contain additives such as a surfactant and a rheology adjuster.

[0177] Rheology modifiers are added primarily to improve the fluidity of the composition for forming an upper layer film. Specific examples include the following: phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically blended in an amount of less than 30% by mass relative to 100% by mass of the entire composition for forming an upper layer film.

[0178] The composition for forming the upper layer film may contain a surfactant to further improve the coating properties for preventing pinholes, striations, etc. and for preventing surface irregularities. Examples of the surfactant include the following.・Nonionic surfactants ・・Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether ・・Polyoxyethylene alkylaryl ethers such as polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether ・・Polyoxyethylene-polyoxypropylene block copolymers ・・Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate ・・Polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate Fluorine-based surfactants such as Eftop EF301, EF303, and EF352 (manufactured by Tochem Products Co., Ltd.), Megafax F171 and F173 (manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430 and FC431 (manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by Asahi Glass Co., Ltd.), and the Ftergent series (manufactured by Neos Corporation); and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The blending amount of these surfactants is usually 0.2% by mass or less, and preferably 0.1% by mass or less, per 100% by mass of the total composition for forming the upper layer film. These surfactants may be added alone or in combination of two or more.

[0179] The content of copolymer (X) in the solid content of the composition for forming an upper layer film is preferably 20% by mass or more, for example, 20 to 100% by mass, or 30 to 100% by mass. The solid content of the composition for forming an upper layer film is preferably 0.1 to 50% by mass, more preferably 0.3 to 30% by mass. Here, the solid content refers to the solid content obtained by removing the solvent from the composition for forming an upper layer film.

[0180] The composition for forming an upper layer film can be produced by mixing copolymer (X), an ether compound having 8 to 16 carbon atoms as a solvent, and, if necessary, the above-mentioned additives according to the composition, for example, by stirring and mixing at room temperature to 40°C.

[0181] <Step (3)> Step (3) is a step in which the block copolymer is phase-separated. Phase separation of the block copolymer can be achieved by a treatment that brings about rearrangement of the block copolymer, such as ultrasonic treatment, solvent treatment, or thermal annealing. In many applications, it is desirable to achieve phase separation of the block copolymer 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 a temperature of 180°C to 300°C in the atmosphere is preferred, 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.

[0182] Phase separation of the block copolymer results in the formation of block copolymer domains oriented substantially perpendicular to the surface of the substrate or underlying film. The domains may have, for example, lamellar, spherical, or cylindrical shapes. The domain spacing is, for example, 50 nm or less. The method of the present invention for producing a substrate having a phase-separated pattern of a block copolymer makes it possible to form a structure having a desired size, shape, orientation, and periodicity.

[0183] When a step of forming an upper layer film is performed between steps (2) and (3), the upper layer film can be peeled off after phase separation of the block copolymer. Peeling can be performed, for example, using a solvent or a mixture of solvents (peeling solvent) that does not damage, dissolve, or substantially swell the block copolymer. The peeled upper layer film can also be isolated and reused. Isolation can be performed by conventional means such as precipitation or distillation.

[0184] (Method for manufacturing a semiconductor device) The method for manufacturing a semiconductor device of the present invention includes the following steps (1) to (5): (1) step: forming an underlayer film on a substrate using the brush-forming composition of the present invention; (2) step: forming a layer containing a block copolymer on the underlayer film; (3) step: phase-separating the block copolymer; (4) step: removing a portion of the phase-separated block copolymer; and (5) step: etching the substrate.

[0185] Furthermore, the method for manufacturing a semiconductor device preferably includes, between steps (2) and (3), a step of forming an upper layer film on the layer containing the block copolymer.

[0186] Details of steps (1) to (3) and the step of forming the upper layer film are as explained in the method of the present invention for producing a substrate having a phase-separated pattern of a block copolymer.

[0187] <Step (4)> Step (4) is a step in which a portion of the phase-separated block copolymer is removed. The layer containing the phase-separated block copolymer has, for example, multiple phases each consisting of multiple types of blocks that constitute the block copolymer. In step (4), at least one of the multiple phases is selectively removed. Methods for selectively removing a phase consisting of blocks include a method of subjecting the layer containing the phase-separated block copolymer to oxygen plasma treatment or hydrogen plasma treatment. By performing step (4), a three-dimensional pattern corresponding to the morphology of the domains is formed from the layer containing the phase-separated block copolymer.

[0188] <Step (5)> Step (5) is a step of etching the substrate. In step (5), the substrate is selectively etched using the three-dimensional pattern obtained in step (4) as a mask. By utilizing the three-dimensional pattern obtained from the layer containing the phase-separated block copolymer, it is possible to impart a desired shape to the substrate to be processed by etching, thereby producing a suitable semiconductor device.

[0189] For etching, for example, tetrafluoromethane (CF ４ ), perfluorocyclobutane (C ４ F ８ ), perfluoropropane (C ３ F ８ Gases such as tetrafluoromethane (CF), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, chlorine trifluoride, chlorine, trichloroborane, and dichloroborane can be used. It is preferable to use a halogen-based gas, and it is more preferable to use a fluorine-based gas. As the fluorine-based gas, for example, tetrafluoromethane (CF ４ ), perfluorocyclobutane (C ４ F ８ ), perfluoropropane (C ３ F ８ ), trifluoromethane, difluoromethane (CH ２ F ２ ) etc.

[0190] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0191] The weight-average molecular weights of the polymers shown in Synthesis Examples 1 and 2 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: TSKgel Super-Multipore HZ-N (2 columns) Column temperature: 40°C Solvent: tetrahydrofuran (THF) Flow rate: 0.35 ml / min Standard sample: polystyrene (manufactured by Tosoh Corporation)

[0192] Synthesis Example 1 4.41 g of 2-vinylnaphthalene (47% by molar ratio to the total of Polymer 1), 4.88 g of 4-tert-butylstyrene (50% by molar ratio to the total of Polymer 1), 0.24 g of 2-hydroxyethyl methacrylate (3% by molar ratio to the total of Polymer 1), and 0.48 g of 2,2'-azobisisobutyronitrile were dissolved in 40.00 g of propylene glycol monomethyl ether acetate in a reaction vessel to obtain a solution. After replacing the atmosphere in the reaction vessel with nitrogen, the solution was heated and stirred at 140°C for approximately 18 hours. This reaction solution was added dropwise to methanol, 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 in terms of polystyrene by GPC was 9,200.

[0193] Synthesis Example 2 4.58 g of 2-vinylnaphthalene (49% by molar ratio to the total polymer 2), 4.86 g of 4-tert-butylstyrene (50% by molar ratio to the total polymer 2), 0.08 g of 2-hydroxyethyl methacrylate (1% by molar ratio to the total polymer 2), and 0.48 g of 2,2'-azobisisobutyronitrile were dissolved in 40.00 g of propylene glycol monomethyl ether acetate in a reaction vessel to obtain a solution. After replacing the atmosphere in the reaction vessel with nitrogen, the solution was heated and stirred at 140°C for approximately 18 hours. This reaction solution was added dropwise to methanol, 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 in terms of polystyrene by GPC was 10,500.

[0194] Example 1 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.002 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 9.999 g of propylene glycol monomethyl ether and 9.999 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 1.

[0195] Example 2 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.01 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 10.395 g of propylene glycol monomethyl ether and 10.395 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 2.

[0196] Example 3 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.02 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 10.890 g of propylene glycol monomethyl ether and 10.890 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 3.

[0197] Example 4 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.04 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 11.880 g of propylene glycol monomethyl ether and 11.880 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 4.

[0198] Example 5 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.01 g of N-methylmorpholine (NMM) were dissolved in 10.395 g of propylene glycol monomethyl ether and 10.395 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 5.

[0199] Example 6 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) and 0.01 g of N,N-dimethyl-4-aminopyridine (DMAP) were dissolved in 10.395 g of propylene glycol monomethyl ether and 10.395 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 6.

[0200] [Example 7] 0.20 g of the polymer (Polymer 1) obtained in Synthesis Example 1 and 0.01 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 10.395 g of propylene glycol monomethyl ether and 10.395 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 7.

[0201] [Example 8] 0.20 g of the polymer (Polymer 2) obtained in Synthesis Example 2 and 0.01 g of diazabicycloundecene (DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene) were dissolved in 10.395 g of propylene glycol monomethyl ether and 10.395 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare brush-forming composition 8.

[0202] Example 9 The brush-forming composition 1 prepared in Example 1 was spin-coated onto a silicon wafer and heated on a hot plate at 150°C for 1 minute. The wafer was then immersed in propylene glycol monomethyl ether acetate at room temperature for 1 minute to remove any polymer not adhering to the silicon wafer, yielding a brush-adhered film. The thickness of the brush-adhered film after immersion was measured using an ellipsometric film thickness measuring device RE-3100 (SCREEN Corporation). The results are shown in Table 1.

[0203] [Examples 10 to 16] The thicknesses of the brush-adhered films prepared in the same manner as in Example 9 were measured, except that brush-forming compositions 2 to 8 prepared in Examples 2 to 8 were used instead of brush-forming composition 1. The results are shown in Tables 1 to 3.

[0204] Comparative Example 1: 0.20 g of hydroxyl-terminated polystyrene (manufactured by POLYMER SOURCE INC., Mw = 9500, polydispersity = 1.04) was dissolved in 9.90 g of propylene glycol monomethyl ether and 9.90 g of propylene glycol monomethyl ether acetate. The solution was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare Comparative Composition 1.

[0205] Comparative Example 2: 0.20 g of the polymer (Polymer 1) obtained in Synthesis Example 1 was dissolved in 9.90 g of propylene glycol monomethyl ether and 9.90 g of propylene glycol monomethyl ether acetate, and then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare Comparative Composition 2.

[0206] Comparative Example 3: 0.20 g of the polymer (Polymer 2) obtained in Synthesis Example 2 was dissolved in 9.90 g of propylene glycol monomethyl ether and 9.90 g of propylene glycol monomethyl ether acetate, and then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare Comparative Composition 3.

[0207] [Comparative Examples 4 to 6] Brush-attached films were prepared in the same manner as in Example 9, except that comparative compositions 1 to 3 prepared in Comparative Examples 1 to 3 were used instead of brush-forming composition 1. The thicknesses of the brush-attached films were then measured in the same manner as in Example 9. The results are shown in Tables 1 to 3.

[0208]

[0209]

[0210] In the tables, the amount (%) of additive added is mass % relative to the brush polymer. Table 1 shows the ratio of each deposited film thickness to the deposited film thickness of Comparative Example 4 as the deposited film thickness ratio. Table 2 shows the ratio of each deposited film thickness to the deposited film thickness of Comparative Example 5 as the deposited film thickness ratio. Table 3 shows the ratio of each deposited film thickness to the deposited film thickness of Comparative Example 6 as the deposited film thickness ratio.

[0211] As shown in Tables 1 to 3, the brush material of the present invention using the base component as an additive can increase the thickness of the film deposited on the substrate.

Claims

1. A brush-forming composition used to phase-separate a block copolymer in a layer containing the block copolymer formed on a substrate, comprising: A method for preparing a polymeric composition comprising the steps of: The brush-forming composition, wherein the organic base is at least one of the compounds represented by the following formulas (III) to (V), 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, 1,4-diazabicyclo[2.2.2]octane, 1,5,7-triazabicyclo[4.4.0]decene-5, and 7-methyl-1,5,7-triazabicyclo[4.4.0]decene-5. 【Chemistry 1】 In formula (III), R 21 to R 24 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms; and L represents an alkylene group having 1 to 5 carbon atoms. In formula (IV), Y represents NR 32 , O, or S. R 31 and R 32 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms, or a sulfonic acid alkyl group having 1 to 4 carbon atoms. In formula (V), R 41 to R 43 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or -N(R 51 )(R 52 ) (R 51 and R 52 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms).

2. 2. The brush-forming composition according to claim 1, wherein the organic base is at least one of N-methylmorpholine, N,N-dimethyl-4-aminopyridine, and 1,8-diazabicyclo[5.4.0]undecene-7.

3. The brush-forming composition according to claim 1, wherein the content of the organic base is 0.1% by mass to 30% by mass relative to the brush polymer.

4. The brush-forming composition according to claim 1, wherein the content of the organic base is 0.5% by mass to 15% by mass relative to the brush polymer.

5. The brush-forming composition of claim 1 , wherein the brush polymer has functional groups capable of bonding to the substrate.

6. The brush-forming composition according to claim 5 , wherein the functional group capable of bonding to a substrate is a hydroxy group, an amino group, or a sulfonic acid group.

7. The brush-forming composition according to claim 1 , wherein the brush polymer is an addition polymerization type polymer.

8. The brush-forming composition according to claim 1 , which is an underlayer film-forming composition for forming an underlayer film for a layer containing the block copolymer.

9. A brush-forming composition used to phase-separate a block copolymer in a layer containing the block copolymer formed on a substrate, the brush-forming composition containing a brush polymer, an organic base, and a solvent being applied to a substrate and heated to obtain a precursor film of the underlayer film, the substrate being obtained by exposing the precursor film to a solvent.

10. (1) A step of forming an underlayer film on a substrate using a brush-forming composition used for phase-separating a block copolymer in a layer containing the block copolymer formed on a substrate, the brush-forming composition including a brush polymer, an organic base, and a solvent; (2) forming a layer containing a block copolymer on the underlayer film; (3) phase separating the block copolymer; A method for producing a substrate having a phase-separated pattern of a block copolymer, comprising:

11. The method according to claim 10, further comprising a step between the steps (2) and (3), of forming an upper layer film on the layer containing the block copolymer.

12. The step (1) A process in which the brush-forming composition is applied onto the substrate; a treatment in which the brush-forming composition applied onto the substrate is heated to form a precursor film of an underlayer film; a treatment in which the precursor film of the underlayer film is exposed to a solvent to obtain the underlayer film; The method of claim 10, comprising:

13. (1) A step of forming an underlayer film on a substrate using a brush-forming composition used for phase-separating a block copolymer in a layer containing the block copolymer formed on a substrate, the brush-forming composition including a brush polymer, an organic base, and a solvent; (2) forming a layer containing a block copolymer on the underlayer film; (3) phase separating the block copolymer; (4) removing a portion of the phase separated block copolymer; (5) the substrate is etched; and A method for manufacturing a semiconductor device comprising the steps of:

14. The method according to claim 13, further comprising a step between the steps (2) and (3) of forming an upper layer film on the layer containing the block copolymer.

15. The step (1) A process in which the brush-forming composition is applied onto the substrate; a treatment in which the brush-forming composition applied onto the substrate is heated to form a precursor film of an underlayer film; a treatment in which the precursor film of the underlayer film is exposed to a solvent to obtain the underlayer film; The method of claim 13, comprising:

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