Vertically phase-separated block copolymer layers

Abstract

Provided are: a layer including a block copolymer in which a microphase-separated structure of the block copolymer has been induced perpendicular to a substrate, this process being difficult in heating under atmospheric pressure; a method for producing the layer; and a method for producing a semiconductor device in which is used a vertically phase-separated block copolymer layer.　A vertically phase-separated block copolymer layer formed by heating at a pressure below atmospheric pressure and a temperature at which induced self-assembly can occur. The vertical phase separation preferably includes a cylinder-shaped portion. The cylinder-shaped portion preferably includes PMMA. The heating temperature is preferably 270°C or higher. It is furthermore preferable to have a layer that neutralizes the surface energy of the block copolymer beneath the block copolymer layer.

Description

[Technical Field]

[0001] The present invention relates to a vertically phase-separated block copolymer layer (e.g., a diblock copolymer layer, a triblock copolymer layer, or a tetrablock copolymer layer), preferably a layer containing vertically phase-separated polystyrene-block (hereinafter abbreviated as "b")-polymethyl methacrylate (PS-b-PMMA), which utilizes a block copolymer self-assembly technique in the field of semiconductor lithography; a method for producing the layer; and a method for producing a semiconductor device using the vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer. [Background technology]

[0002] In recent years, with the further miniaturization of large-scale integrated circuits (LSIs), there has been a demand for technologies for processing ever more delicate structures. In response to this demand, pattern formation technologies are being put into practical use to form ever finer patterns by utilizing phase-separated structures formed by the self-assembly of block copolymers, in which incompatible polymers are bonded together. For example, a pattern formation method has been proposed in which a self-assembled film containing a block copolymer, in which two or more polymers are bonded together, is formed on the surface of a substrate, the block copolymer is phase-separated in the self-assembled film, and at least one of the polymer phases constituting the block copolymer is selectively removed. Patent Document 1 discloses a composition for forming an underlayer film of a self-assembled film, which contains a polycyclic aromatic vinyl compound. Non-Patent Document 1 discloses a technique for induced self-assembly of a self-assembled film by reducing the oxygen concentration in the atmosphere. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 097993 [Non-patent literature]

[0004] [Non-Patent Document 1] Nathalie Frolet et al., “Expanding DSA process window with atmospheric control”, Proc. of SPIE Vol.11326 113261J-1~J-6(2020) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a layer containing a block copolymer, preferably PS-b-PMMA, in which a microphase-separated structure of the block copolymer, preferably PS-b-PMMA, is induced vertically to the substrate without causing alignment defects, which is difficult to achieve by heating under atmospheric pressure; a method for producing the same; and a method for producing a semiconductor device using a vertically phase-separated block copolymer (preferably PS-b-PMMA) layer. [Means for solving the problem]

[0006] The present invention encompasses the following. [1] Vertically phase-separated block copolymer layers formed by heating at temperatures where directed self-assembly can occur at subatmospheric pressure. [2] The block copolymer layer according to [1], wherein the block copolymer is PS-b-PMMA. [3] The vertically phase-separated block copolymer layer according to [1] or [2], wherein the vertical phase separation comprises cylindrical portions. [4] The vertically phase-separated block copolymer layer according to [3], wherein the cylindrical portion contains PMMA. [5] The vertically phase-separated block copolymer layer according to any one of [1] to [4], wherein the heating temperature is 270° C. or higher. [6] The vertically phase-separated block copolymer layer according to any one of [1] to [5], further comprising a layer for neutralizing the surface energy of the block copolymer below the block copolymer layer. [7] The vertically phase-separated block copolymer layer according to [6], wherein the neutralization layer contains a polymer having a unit structure derived from an aromatic compound. [8] The vertically phase-separated block copolymer layer according to [7], wherein the unit structure derived from the aromatic compound is contained in an amount of 50 mol % or more relative to the entire polymer. [9] The vertically phase-separated block copolymer layer according to [6], wherein the neutralization layer contains a polymer having a unit structure containing an aliphatic polycyclic structure of an aliphatic polycyclic compound in its main chain.

[10] The vertically phase-separated block copolymer layer according to [6], wherein the neutralization layer comprises a polysiloxane.

[11] The vertically phase-separated block copolymer layer according to any one of [6] to [8], wherein the neutralization layer contains a polymer having a reactive substituent at its terminal.

[12] The vertically phase-separated block copolymer layer according to any one of [1] to

[10] above, formed on a substrate.

[13] 1. A method for producing a vertically phase separated block copolymer layer, comprising: A method for producing a vertically phase-separated block copolymer layer, comprising the steps of forming a block copolymer layer on a substrate and then heating the substrate at a pressure less than atmospheric pressure.

[14] A method for manufacturing a semiconductor device, comprising the steps of: forming a block copolymer layer on a substrate; heating the substrate at a pressure less than atmospheric pressure; etching the vertically phase-separated block copolymer layer; and etching the substrate. [Effects of the Invention]

[0007] The vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, of the present application is prepared by heating a block copolymer layer, preferably a PS-b-PMMA layer, before phase separation at a pressure below atmospheric pressure, thereby inducing directed self-organization of the block copolymer, preferably PS-b-PMMA, and inducing a microphase-separated structure perpendicular to the substrate. The vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer (which may contain PS-b-PMMA but preferably contains only PS-b-PMMA), preferably a block copolymer layer having at least a cylindrical shape (i.e., containing one or more cylindrical shapes), preferably a PS-b-PMMA layer, is preferably a block copolymer layer having a cylindrical shape, preferably a PS-b-PMMA layer. By selectively etching the vertically phase-separated block copolymer layer, preferably the layer containing PS-b-PMMA, a semiconductor substrate can be processed to produce a semiconductor device. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram showing PS-b-PMMA-induced self-assembly. [Figure 2] FIG. 1 is a schematic diagram showing a substrate, an underlayer film layer (referred to as a neutralization layer in the present application), and a self-organization forming layer (referred to as a PS-b-PMMA layer in the present application). [Figure 3] 1 is an electron microscope photograph illustrating the "vertical alignment" and "misalignment" referred to in the present application. DETAILED DESCRIPTION OF THE INVENTION

[0009] Vertically phase-separated block copolymer layer The vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, of the present application can be formed by applying a known block copolymer layer, preferably a block copolymer layer-forming composition containing PS-b-PMMA, preferably a PS-b-PMMA layer-forming composition, onto a substrate and heating it at a pressure less than atmospheric pressure.

[0010] The vertical phase separation may occur in at least a portion of the block copolymer layer, preferably the PS-b-PMMA layer. Preferably, the vertical phase separation occurs throughout the entire block copolymer layer, preferably the PS-b-PMMA layer (the area of ​​vertical phase separation is 80% or more, more preferably 90% or more, even more preferably 95% or more, and most preferably 100% of the entire surface coated with the block copolymer layer, preferably the PS-b-PMMA layer). The area of ​​vertical phase separation can be determined from the average area of ​​vertical phase separation in the image obtained by electron microscopy from three or more locations on the top surface of a portion of the substrate surface after the phase separation step. As shown in the example of the electron micrograph in Figure 3, if there are areas of misalignment in the image obtained by electron microscopy from the top surface of a portion of the substrate surface after the phase separation step, this can be determined to be misaligned.

[0011] The diblock copolymer PS-b-PMMA can be produced by a known method, or a commercially available product may be used.

[0012] The block copolymer may also be a block copolymer obtained by combining a silicon-free polymer having as a constituent unit styrene or a derivative thereof which may be substituted with an organic group, or a silicon-free polymer having as a constituent unit a structure derived from lactide, with a silicon-containing polymer having as a constituent unit styrene substituted with a silicon-containing group. Among these, a combination of a silylated polystyrene derivative and a polystyrene derivative polymer, or a combination of a silylated polystyrene derivative polymer and polylactide is preferred.

[0013] Among these, a combination of a silylated polystyrene derivative having a substituent at the 4-position and a polystyrene derivative polymer having a substituent at the 4-position, or a combination of a silylated polystyrene derivative polymer having a substituent at the 4-position and polylactide is preferred. More preferred specific 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).

[0014] 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). The most preferred examples of the block copolymer include poly(4-methoxystyrene) / poly(4-trimethylsilylstyrene) copolymer and polystyrene / poly(4-trimethylsilylstyrene) copolymer. The entire disclosure of WO2018 / 135456 is incorporated herein by reference.

[0015] 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): [ka] (In formula (1-1c) or formula (1-2c), R 1 and R 2 each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms; R 3 ~R 5 each independently represents a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cyano group, an amino group, an amido group, or a carbonyl group.

[0016] The silicon-containing group may contain one silicon atom. The silicon-containing polymer may contain a unit structure represented by the following formula (2c): [ka] (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.

[0017] Furthermore, as the block copolymer, block copolymers described in JP-A-2019-507815, including the following [BCP1] to [BCP4], may be used. [BCP1] Block copolymer containing 5-vinylbenzo[d][1,3]dioxole. [BCP2] The block copolymer according to [BCP1], wherein the block copolymer further comprises a silicon-containing block. [BCP3] The block copolymer according to [BCP2], wherein the block copolymer further comprises pentamethyldisilylstyrene. [BCP4] The block copolymer according to [BCP3], wherein the block copolymer is poly(5-vinylbenzo[d][1,3]dioxole)-b-poly(pentamethyldisilylstyrene).

[0018] The synthesis of the above-described poly(5-vinylbenzo[d][1,3]dioxole-block-4-pentamethyldisilylstyrene) is shown in Scheme 1 below. [ka]

[0019] 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.

[0020] Also usable are block copolymers made of combinations of the following monomers: styrene, methyl methacrylate, dimethylsiloxane, propylene oxide, ethylene oxide, vinylpyridine, vinylnaphthalene, D,L-lactide, methoxystyrene, methylenedioxystyrene, trimethylsilylstyrene, and pentamethyldisilylstyrene.

[0021] 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.

[0022] 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, and 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.

[0023] Further examples include block copolymers formed from a combination of the organic polymers and / or metal-containing polymers described below.

[0024] 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(ethyl oxazoline), poly(alkyl acrylate), poly(acrylic acid), poly(methyl methacrylate ... Examples of suitable poly(N-alkylacrylamides) include, but are not limited to, 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.

[0025] 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).

[0026] 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-poly(DL-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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Examples of siloxane derivatives include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, and methylphenylsiloxane. Examples of the alkylene oxide include ethylene oxide, propylene oxide, isopropylene oxide, and butylene oxide.

[0031] 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, and styrene-polyacrylic acid block copolymer.

[0032] One method for synthesizing block copolymers is by living radical polymerization, living cationic polymerization, or living anionic 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 propagation activity during the polymerization reaction. By preventing chain transfer, a polymer (A) of uniform length can be obtained. By using the growing end of this polymer (A) to add a different monomer (b), polymerization can proceed in the presence of this monomer (b) to form a block copolymer (AB).

[0033] For example, when there are two types of blocks, A and B, the molar ratio of polymer chain (A) to polymer chain (B) can be 1:9 to 9:1, preferably 3:7 to 7:3.

[0034] The volume ratio of the block copolymer used in the present invention is, for example, 30:70 to 70:30. The homopolymer A or B is a polymerizable compound having at least one radically polymerizable reactive group (vinyl group or vinyl group-containing organic group).

[0035] The weight average molecular weight Mw of the block copolymer used in the present invention is preferably 1,000 to 100,000, or 5,000 to 100,000. If it is less than 1,000, the coating property onto the base substrate may be poor, and if it is 100,000 or more, the solubility in the solvent may be poor.

[0036] The polydispersity (Mw / Mn) of the block copolymer of the present invention is preferably 1.00 to 1.50, particularly preferably 1.00 to 1.20.

[0037] In one embodiment of the invention, the block copolymer is PS-b-PMMA.

[0038] The block copolymer layer-forming composition (preferably, the PS-b-PMMA layer-forming composition) of the present application may have a solids content of 0.1 to 10 mass %, 0.1 to 5 mass %, or 0.1 to 3 mass %. The solids content is the percentage remaining after excluding the solvent from the block copolymer layer-forming composition (preferably, the PS-b-PMMA layer-forming composition).

[0039] The proportion of the block copolymer in the solid content can be 30 to 100 mass %, or 50 to 100 mass %, or 50 to 90 mass %, or 50 to 80 mass %.

[0040] <Solvent> The solvent contained in the block copolymer layer-forming composition, preferably the PS-b-PMMA layer-forming composition, referred to herein, is not particularly limited as long as it can dissolve the block copolymer, preferably PS-b-PMMA. However, it is preferably an organic solvent used in semiconductor lithography processes. Specific examples include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cyclohexane, cyclohexane-1, cyclohexane-2, cyclohexane-3, cyclohexane-4, cyclohexane-5, cyclohexane-6, cyclohexane-7, cyclohexane-8, cyclohexane-9, cyclohexane-10, cyclohexane-11, cyclohexane-12, cyclohexane-13, cyclohexane-14, cyclohexane-15, cyclohexane-16, cyclohexane-17, cyclohexane-18, cyclohexane-19, cyclohexane-20, cyclohexane-21, cyclohexane-22, cyclohexane-23, cyclohexane-24, cyclohexane-25, cyclohexane-26, cyclohexane-27, cyclohexane-28, cyclohexane-29, cyclohexane-30, cyclohexane-31, cyclohexane-32, cyclohexane-33, cyclohexane-34, cyclohexane-35, cyclohexane-36, cyclohexane-37, cyclohexane-38, cyclohexane-39, cyclohexane-40, cyclohexane-41, cyclohexane-42, cyclohexane-43, cyclohexane-44, cyclohexane-45, cyclohexane-45, cyclohexane Examples of suitable solvents include cycloheptanone, 4-methyl-2-pentanol, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0041] Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, butyl acetate, methyl isobutyl ketone, and cyclohexanone are preferred, with propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate being particularly preferred.

[0042] Alternatively, the solvent contained in the block copolymer layer-forming composition, preferably the PS-b-PMMA layer-forming composition, 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.

[0043] The composition may contain 0.3 to 2.0% by weight of a high-boiling point solvent (B) based on the total amount of solvent contained in the composition.

[0044] Preferred examples of the low boiling point 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).

[0045] 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).

[0046] Two or more low-boiling point solvents (A) and two or more high-boiling point solvents (B) can be selected and mixed for use. In a preferred embodiment, the composition contains 0.3 to 2.0 wt % of the high-boiling point solvent (B) based on the total solvent content. Most preferably, the composition contains 0.5 to 1.5 wt % of the high-boiling point solvent (B).

[0047] The atmospheric pressure is 760,000 mTorr. There are no particular limitations on the "lower than atmospheric pressure" as long as it is less than 760,000 mTorr, but it is preferably, for example, 500,000 mTorr or less, 300,000 mTorr or less, 100,000 mTorr or less, 50,000 mTorr or less, 30,000 mTorr or less, 20,000 mTorr or less, 10,000 mTorr or less, 9,000 mTorr or less, 8,000 mTorr or less, 7,000 mTorr or less, 6,000 mTorr or less, 5,000 mTorr or less, 4,000 mTorr or less, 3,000 mTorr or less, 2,000 mTorr or less, 1,000 mTorr or less, 900 mTorr or less, or 800 mTorr or less. For example, it is preferably 10,000 to 10 mTorr, 1,000 to 50 mTorr, or 800 to 50 mTorr.

[0048] The gas contained in the atmosphere (the atmosphere during the directed self-assembly of the block copolymer, preferably PS-b-PMMA) when the pressure is less than atmospheric pressure is not particularly limited. It may be air, an N2 / O2 mixed gas (any ratio), N2 only, or O2 only. Other gases that do not affect the directed self-assembly (vertical phase separation) of the block copolymer, preferably PS-b-PMMA, may also be contained.

[0049] The heating is a heat treatment performed on a film formed by applying a composition containing a block copolymer, preferably PS-b-PMMA, to the upper surface of a typically flat semiconductor substrate (such as a silicon wafer), as described in detail below. The heating is performed at a temperature at which directed self-assembly can occur. The heating temperature is typically between 230°C and 350°C, but preferably 270°C or higher. In another embodiment, the heating temperature is preferably between 260°C and 340°C, 270°C and 330°C, or 270°C and 320°C. The heating time is typically between 1 minute and 1 hour, but may be between 2 minutes and 30 minutes, or 3 minutes and 10 minutes.

[0050] For example, at high temperatures of 300°C or higher (300°C to 330°C), vertical phase separation is possible in a relatively short time such as 1 to 10 minutes, 1 to 5 minutes, or 1 to 3 minutes.

[0051] The vertical phase separation preferably includes cylindrical portions, which are also called columnar portions and are formed by self-assembly (self-organization) of blocks of a block copolymer that have a smaller weight-average molecular weight.

[0052] The weight-average molecular weights of PS and PMMA in the PS-b-PMMA are, for example, in the range of 20,000 to 100,000 for PS and 5,000 to 50,000 for PMMA. It is preferable to use PS with a higher weight-average molecular weight than PMMA. The weight-average molecular weight ratio of PS to PMMA (PS / PMMA ratio) is, for example, 20.0 to 1.1, 10.0 to 1.1, 5.0 to 1.1, or 3.0 to 1.1.

[0053] The cylindrical portion may contain either PS or PMMA, but preferably contains PMMA. When the weight-average molecular weight of PS is higher than that of PMMA, as described above, PMMA forms a cylindrical shape and PS self-assembles around it, forming a vertical phase-separated structure with PMMA cylinders scattered throughout. A schematic diagram is shown in Figure 1. In Figure 1, the cylindrical shape at the end of the arrow extending from the word "PMMA" indicates the cylindrical portion referred to in this application.

[0054] It is preferable to further have a surface energy neutralizing layer of the block copolymer layer, preferably PS-b-PMMA, below the block copolymer layer, preferably PS-b-PMMA.

[0055] The surface energy neutralization mentioned above refers to bringing the surface energy of the entire block copolymer, which has a hydrophilic portion (e.g., PMMA) and a hydrophobic portion (e.g., PS), close to or equal to the surface energy of the substrate or other surface in contact with the block copolymer, in order to achieve vertical phase separation of the block copolymer. When the surface energies of the two are close to or the same, a vertical phase-separated structure is formed. Therefore, for vertical phase separation of a block copolymer layer, preferably a PS-b-PMMA layer, it is common to perform this by forming a surface energy neutralization layer on the substrate surface (i.e., beneath the block copolymer layer, preferably the PS-b-PMMA layer). However, this does not apply if the substrate surface already has the same or similar surface energy as the entire block copolymer. This theory is described, for example, in Macromolecules 2006, 39, 2449-2451.

[0056] The neutralization layer may include a polymer having a unit structure derived from an aromatic compound.

[0057] The aromatic compound preferably contains an aryl group having 6 to 40 carbon atoms.

[0058] Examples of the aryl group having 6 to 40 carbon atoms include a phenyl group, an o-methylphenyl group, a m-methylphenyl group, a p-methylphenyl group, an o-chlorophenyl group, a 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, a 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, a phenyl group, an α-naphthyl group (=1-naphthyl group), or a β-naphthyl group (=2-naphthyl group) is preferred.

[0059] 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. The upper limit is, for example, 95 mol % or 90 mol %.

[0060] The polymer 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.

[0061] The polymer preferably contains 50 mol% or more of the aromatic compound-derived unit structure relative to the entire polymer. More preferably, the polymer 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 structure relative to the entire polymer.

[0062] The neutralization layer may be a neutralization layer derived from the underlayer film-forming composition for a self-assembled film described in WO2014 / 097993.

[0063] The neutralization layer may contain a polymer having a unit structure derived from a polycyclic aromatic vinyl compound, and may contain a polymer having 0.2 mol % or more of a unit structure of a polycyclic aromatic vinyl compound per total unit structure of the polymer.

[0064] The polymer may be a polymer having 20 mol % or more of unit structures of an aromatic vinyl compound per total unit structures of the polymer, and 1 mol % or more of unit structures of a polycyclic aromatic vinyl compound per total unit structures of the aromatic vinyl compound.

[0065] 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.

[0066] The aromatic vinyl compound may include an optionally substituted styrene, and an optionally substituted vinylnaphthalene, an optionally substituted acenaphthylene, or an optionally substituted vinylcarbazole, and the polycyclic aromatic vinyl compound may be vinylnaphthalene, an optionally substituted acenaphthylene, or an optionally substituted vinylcarbazole.

[0067] The aromatic vinyl compound may be 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, each of which may be substituted.

[0068] The aromatic vinyl compound may consist solely of a polycyclic aromatic vinyl compound, and the aromatic vinyl compound may be vinylnaphthalene, acenaphthylene, or vinylcarbazole, each of which may be substituted.

[0069] The polymer may have 60 to 95 mol % of unit structures of an aromatic vinyl compound per total unit structures of the polymer.

[0070] The polymer further has a unit structure having a crosslinking group, and the crosslinking group may be a hydroxy group, an epoxy group, a protected hydroxy group, or a protected carboxyl group.

[0071] The neutralization layer may be formed from a neutralization layer-forming composition. The neutralization layer-forming composition may contain a polymer having a unit structure derived from the aromatic compound and / or a polymer having a unit structure derived from the polycyclic aromatic vinyl compound, and examples of the embodiments of these polymers are the same as those described above for the neutralization layer. In this specification, the term "underlayer film" may be used synonymously with "neutralization layer," and the term "underlayer film-forming composition" may be used synonymously with "neutralization layer-forming composition." The neutralizing layer-forming composition of the present application may contain a crosslinking agent, an acid, or an acid generator.

[0072] <Crosslinking agent> Examples of crosslinking agents used in the neutralization layer-forming composition of the present application include melamine-based compounds, substituted urea-based compounds, and polymer-based compounds thereof. Crosslinking agents having at least two crosslink-forming substituents are preferred, specifically compounds such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, and methoxymethylated thiourea. Condensates of these compounds can also be used.

[0073] The crosslinking agent of the present application may also be a nitrogen-containing compound described in WO2017 / 187969, which has 2 to 6 substituents bonded to nitrogen atoms and represented by the following formula (1d) per molecule. [ka] (wherein R1 represents a methyl group or an ethyl group).

[0074] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (1d) in one molecule may be a glycoluril derivative represented by the following formula (1E). [ka] (In the formula, four R1s each independently represent a methyl group or an ethyl group, and R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.)

[0075] Examples of the glycoluril derivative represented by the formula (1E) include compounds represented by the following formulae (1E-1) to (1E-6). [ka]

[0076] A nitrogen-containing compound having 2 to 6 substituents represented by the formula (1d) in one molecule, such as a compound represented by the formula (1E), can be obtained by reacting a nitrogen-containing compound having 2 to 6 substituents bonded to a nitrogen atom in one molecule, represented by the following formula (2d), with at least one compound represented by the following formula (3d). [ka] (In the formula, R1 represents a methyl group or an ethyl group, and R4 represents an alkyl group having 1 to 4 carbon atoms.)

[0077] The glycoluril derivative represented by the formula (1E) can be obtained by reacting a glycoluril derivative represented by the following formula (2E) with at least one compound represented by the formula (3d).

[0078] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (2d) in one molecule is, for example, a glycoluril derivative represented by the following formula (2E). [ka] (In the formula, R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R4 each independently represent an alkyl group having 1 to 4 carbon atoms.)

[0079] Examples of glycoluril derivatives represented by the formula (2E) include compounds represented by the following formulae (2E-1) to (2E-4): Furthermore, examples of compounds represented by the formula (3d) include compounds represented by the following formulae (3d-1) and (3d-2): [ka] [ka]

[0080] The nitrogen-containing compound having 2 to 6 substituents bonded to the nitrogen atom and represented by the following formula (1d) per molecule is similar to the content described in WO2017 / 187969.

[0081] The amount of the crosslinking agent added to the neutralization layer-forming composition of the present invention is 0.001 to 80% by mass, preferably 0.01 to 50% by mass, and more preferably 0.05 to 40% by mass, based on the total solid content. These crosslinking agents may cause a crosslinking reaction by self-condensation, but when crosslinkable substituents are present in the above-mentioned polymer of the present invention, they can cause a crosslinking reaction with the crosslinkable substituents.

[0082] <Acid or acid generator> The neutralization layer-forming composition of the present invention may contain an acid and / or an acid generator as a catalyst for accelerating the crosslinking reaction. Examples of acids include acidic compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate (=pyridinium-p-toluenesulfonate), salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid. Examples of acid generators include thermal acid generators such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters. The amount of these compounds to be added is 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 3% by mass, based on the total solids content of the neutralization layer-forming composition of the present invention.

[0083] The acid generator may be a photoacid generator in addition to the thermal acid generator. Examples of the photoacid generator contained in the neutralization layer-forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0084] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0085] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide. Examples of disulfonyldiazomethane compounds include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0086] The photoacid generators may be used singly or in combination of two or more. When a photoacid generator is used, the proportion thereof is 0.01 to 5 parts by mass, or 0.1 to 3 parts by mass, or 0.5 to 1 part by mass, per 100 parts by mass of the solid content of the neutralization layer-forming composition of the present invention.

[0087] Other details of the neutralization layer-forming composition for forming the neutralization layer, which contains a polymer having a unit structure derived from the polycyclic aromatic vinyl compound, other than those described in this specification, are similar to those described in the WO2014 / 097993 specification regarding the underlayer film-forming composition for self-assembled films.

[0088] Other examples of the neutralization layer include an underlayer film-forming composition described in WO2018 / 135455 that 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, other than the unit structure (A); (C) a unit structure derived from a compound containing a (meth)acryloyl group but not containing a hydroxy group; (D) a unit structure derived from a cross-linking group-containing compound, The underlayer film may be formed from an underlayer film-forming composition in which the copolymerization ratios 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).

[0089] The unit structure (A) derived from a styrene compound containing a tert-butyl group may be represented by formula (1). [ka] (In formula (1), R 1 From R 3 One or two of these are tert-butyl groups.)

[0090] The unit structure (D) derived from the cross-linking group-containing compound may be represented by formula (2-1), (2-2), (3-1) or (3-2). [ka] [ka] (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 amido group, an alkoxycarbonyl group, or a thioalkyl group, and n represents an integer of 1 to 7.) [ka] [ka] (In formulas (3-1) and (3-2), R 4 represents a hydrogen atom or a methyl group, R 5represents 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 represented by formula (4-1) or (4-2). [ka] [ka] (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 amido 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 represented by formula (5-1) or (5-2). [ka] [ka] (In formulas (5-1) and (5-2), R 9 represents a hydrogen atom or a methyl group, and 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.

[0093] The unit structure (B) other than the above (A), which is derived from the aromatic-containing vinyl compound not containing a hydroxy group, may be a unit structure derived from vinylnaphthalene.

[0094] Other details of the underlayer film-forming composition of the present invention other than those described in this specification are as described in the specification of WO2018 / 135455.

[0095] Other examples of the neutralization layer include a primer described in the specification of JP 2012-062365 A, which is used to phase separate a layer formed on a substrate and containing a block copolymer in which multiple types of polymers are bonded, and which is formed from a primer characterized by containing a resin component and in which 20 mol % to 80 mol % of the structural units of the entire resin component are structural units derived from aromatic ring-containing monomers.

[0096] The resin component may contain a structural unit derived from a non-aromatic ring-containing monomer.

[0097] The non-aromatic ring-containing monomer may be a vinyl compound or a (meth)acrylic acid compound containing at least one atom selected from the group consisting of N, O, Si, P, and S.

[0098] The aromatic ring-containing monomer may be selected from the group consisting of aromatic compounds having 6 to 18 carbon atoms and a vinyl group, aromatic compounds having 6 to 18 carbon atoms and a (meth)acryloyl group, and phenols that are constituent components of novolac resins. Further, a polymerizable monomer may be contained, or the resin component may contain a polymerizable group.

[0099] The term "(meth)acrylic acid" refers to either or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. The same applies to "(meth)acrylic acid ester," "(meth)acrylate," and "(meth)acryloyl."

[0100] Examples of aromatic compounds having 6 to 18 carbon atoms and a vinyl group include monomers having groups in which hydrogen atoms in an aromatic ring are substituted with vinyl groups, such as phenyl, biphenyl, fluorenyl, naphthyl, anthryl, and phenanthryl groups, and heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen, sulfur, and nitrogen atoms. These may have a substituent other than the vinyl group.

[0101] Examples thereof 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.

[0102] Examples of aromatic compounds having 6 to 18 carbon atoms and a (meth)acryloyl group include monomers having groups in which hydrogen atoms in an aromatic ring, such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group, have been substituted with a (meth)acryloyl group, and heteroaryl groups in which some of the carbon atoms constituting the ring of these groups have been substituted with heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. These may have a substituent other than the (meth)acryloyl group.

[0103] Examples include benzyl methacrylate, 1-(meth)acrylic acid-naphthalene, 4-methoxynaphthalene (meth)acrylic acid, 9-(meth)acrylic acid anthracene, phenoxyethyl (meth)acrylate, etc. Details of the above primers other than those described in this specification are subject to the content described in JP 2012-062365 A.

[0104] The weight average molecular weight of the polymer contained in the neutralization layer of the present invention is, for example, 1,000 to 50,000, or 2,000 to 30,000.

[0105] The neutralization layer-forming composition of the present invention preferably contains the polymer used in the neutralization layer and a solvent. Specific examples of the preferred solvent are the same as those contained in the block copolymer layer-forming composition (preferably, the PS-b-PMMA layer-forming composition) described above.

[0106] In one embodiment of the present invention, the neutralization layer may contain a polymer having a unit structure containing an aliphatic polycyclic structure of an aliphatic polycyclic compound in its main chain.

[0107] The polymer may be a polymer having a unit structure containing, in the main chain, an aliphatic polycyclic structure of an aliphatic polycyclic compound and an aromatic ring structure of an aromatic ring-containing compound. The polymer may be a polymer having a unit structure containing, in its main chain, a polymer chain derived from an aliphatic polycyclic structure of an aliphatic polycyclic compound and a vinyl group of a vinyl group-containing compound.

[0108] The polymer has the following formula (1a): [ka] (In formula (1a), X is a single bond, a divalent group having a vinyl structure derived from a vinyl group-containing compound as a polymer chain, or a divalent group having an aromatic ring-containing structure derived from an aromatic ring-containing compound as a polymer chain, and Y is a divalent group having an aliphatic polycyclic structure derived from an aliphatic polycyclic compound as a polymer chain.) The aliphatic polycyclic compound may be a diene compound having 2 to 6 rings. The aliphatic polycyclic compound may be dicyclopentadiene or norbornadiene. The vinyl group-containing compound may be an alkene, an acrylate, or a methacrylate. The aromatic ring-containing compound may be a monocyclic compound or a heterocyclic compound. The homocyclic compound may be an optionally substituted benzene or an optionally substituted naphthalene. The heterocyclic compound may be an optionally substituted carbazole or an optionally substituted phenothiazine.

[0109] The polymer represented by the above formula (1a) has, for example, unit structures represented by the following formulas (3-1a) to (3-12a). [ka]

[0110] Details of the neutralization layer containing a polymer having a unit structure containing an aliphatic polycyclic structure of the above aliphatic polycyclic compound in its main chain are as described in WO2015 / 041208.

[0111] The neutralization layer of the present application may comprise a polysiloxane. The polysiloxane may be a hydrolysis condensate of silanes including a phenyl group-containing silane.

[0112] The polysiloxane has formula (1b): [ka] (In the formula, R 1 represents an alkoxy group, an acyloxy group, or a halogen atom. 2 represents an organic group containing a benzene ring which may have a substituent and which is bonded to a silicon atom by a Si-C bond) in a proportion of 10 to 100 mol % of all silanes, but this proportion is preferably 80 to 100 mol %.

[0113] The polysiloxane may be a hydrolysis condensate of silanes, containing a silane represented by the above formula (1b), a silane represented by the following formula (2b), and a silane represented by the following formula (3b) in a ratio of silane represented by formula (1b):silane represented by formula (2b):silane represented by formula (3b) of 10-100:0-90:0-50 in mole % based on the total silanes. [ka] (In the formula, R 3 and R 5 represents an alkoxy group, an acyloxy group, or a halogen atom; R 4 represents an organic group containing a hydrocarbon which may have a substituent and which is bonded to a silicon atom via an Si-C bond. The polysiloxane may be a hydrolysis condensate of silanes containing the silanes represented by the formula (1b) and the silanes represented by the formula (2b) in a molar ratio of 10-100:0-90 based on the total silanes. The polysiloxane may be a hydrolysis condensate of silanes containing the silanes represented by the formula (1b) and the silanes represented by the formula (3b) in a molar ratio of 10-100:0-90 based on the total silanes. In the above formula (1b), R 2 In the above formula (2b), R may be a phenyl group. 4 may be a methyl group or a vinyl group. 5 may be an ethyl group. Details of the neutralization layer containing the polysiloxane are as described in WO2013 / 146600.

[0114] As the neutralization layer, a vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, may be formed using a brush agent.

[0115] For example, in the polymer brush method described in JP 2016-160431 A, a block copolymer underlayer (neutralized layer) may be formed by a method including disposing on a substrate a composition including: a block copolymer comprising a first polymer and a second polymer, wherein the first polymer and the second polymer of the block copolymer are different from each other and the block copolymer forms a layer-separated structure; an addition polymer including a bottle-brush polymer, wherein the bottle-brush polymer includes a polymer having a lower or higher surface energy than the block copolymer; and a solvent.

[0116] Alternatively, a method using a brush agent as described in Science 07 Mar 1997: Vol. 275, Issue 5305, pp. 1458-1460 may be used.

[0117] Preferred brush agents herein include polymers terminated with reactive substituents, i.e., in some embodiments herein, the neutralization layer includes a polymer terminated with reactive substituents. The reactive substituent is a substituent that can bond with silicon, SiN, SiON, a silicon hard mask, etc., and contributes to the block copolymer arrangement as a so-called brush agent. Examples of the reactive substituent include a hydroxy group, a 1,2-ethanediol group, a carboxy group, an amino group, a thiol group, a phosphate group, and a methine group. Specific examples of polymers having reactive substituents at their ends include polystyrene / poly(methyl methacrylate) random copolymers having terminal hydroxyl groups. The molar ratio of polystyrene to the entire random copolymer is preferably 60 mol% or more, 65 mol% or more, 70 mol% or more, 80 mol% or more, 81 mol% or more, 85% or more, or 90 mol% or more. The weight-average molecular weight of the polymer forming the brush agent is, for example, in the range of 5,000 to 50,000. The polydispersity (Mw / Mn) is preferably 1.30 to 2.00.

[0118] The silicon hard mask may be a known silicon hard mask (also referred to as a silicon-containing resist underlayer film), and examples thereof include the silicon hard masks (silicon-containing resist underlayer films) described in WO2019 / 181873, WO2019 / 124514, WO2019 / 082934, WO2019 / 009413, WO2018 / 181989, WO2018 / 079599, WO2017 / 145809, WO2017 / 145808, WO2016 / 031563, and the like.

[0119] <Substrate> A vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, is preferably formed on a substrate. The substrate may be a so-called semiconductor substrate, and examples thereof include silicon wafers, germanium wafers, and wafers of compound semiconductors such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride.

[0120] When a semiconductor substrate having an inorganic film formed on its surface is used, the inorganic film can be formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum deposition, or spin-coating (spin-on-glass: SOG). Examples of the inorganic film include polysilicon film, silicon oxide film, silicon nitride film, BPSG (Boro-Phospho Silicate Glass) film, titanium nitride film, titanium nitride oxide film, tungsten film, gallium nitride film, and gallium arsenide film.

[0121] A neutralization layer-forming composition is applied onto such a semiconductor substrate using an appropriate application method such as a spinner or coater. The composition is then baked using a heating means such as a hot plate to form a neutralization layer. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 to 60 minutes. A baking temperature of 120°C to 350°C and a baking time of 0.5 to 30 minutes are preferred, and a baking temperature of 150°C to 300°C and a baking time of 0.8 to 10 minutes are more preferred.

[0122] The thickness of the neutralized layer to be formed may be, for example, 0.001 μm (1 nm) to 10 μm, 0.002 μm (2 nm) to 1 μm, 0.005 μm (5 nm) to 0.5 μm (500 nm), 0.001 μm (1 nm) to 0.05 μm (50 nm), 0.002 μm (2 nm) to 0.05 μm (50 nm), 0.003 μm (3 nm) to 0.05 μm (50 nm), 0.004 μm (4 nm) to 0.05 μm (50 nm), 0.005 μm (5 nm) to 0.05 μm (50 nm), 0.003 μm (3 nm) to 0.03 μm (30 nm), 0.003 μm (3 nm) to 0.02 μm (20 nm), 0.005 μm (5 nm) to 0.02 μm (20 nm).

[0123] Phase separation of the block copolymer layer can be achieved in the presence of the upper layer film by treatments that result in rearrangement of the block copolymer material, such as ultrasonic treatment, solvent treatment, thermal annealing, etc. In many applications, it is desirable to achieve phase separation of the block copolymer layer simply by heating or so-called thermal annealing. Thermal annealing can be carried out in air or in an inert gas under normal, reduced, or increased pressure conditions.

[0124] <Method for manufacturing vertically phase-separated block copolymer layers> The method for producing a vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, of the present application comprises the steps of forming a block copolymer layer, preferably a PS-b-PMMA layer, on a substrate and then heating the substrate at a pressure less than atmospheric pressure. The detailed conditions and the like are the same as those described above for the vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer.

[0125] Phase separation of a block copolymer layer, preferably a PS-b-PMMA layer, forms block copolymer domains oriented substantially perpendicular to the substrate or neutralization layer surface. The domain morphology may be, for example, lamellar, spherical, or cylindrical. The domain spacing may be, for example, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, or 10 nm or less. The method of the present invention makes it possible to form a vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, having the desired size, shape, orientation, and periodicity.

[0126] <Method of manufacturing a semiconductor device> The vertically phase-separated block copolymer layer, preferably a PS-b-PMMA layer, obtained by the above method can be further subjected to an etching step. Typically, a portion of the phase-separated block copolymer layer, preferably a PS-b-PMMA layer, is removed before etching. Etching can be performed by known means. This method can be used to manufacture semiconductor substrates.

[0127] That is, the method for manufacturing a semiconductor device according to the present invention includes the steps of (1) forming a neutralized layer on a substrate using the neutralized layer-forming composition according to the present invention, (2) forming a block copolymer layer, preferably a PS-b-PMMA layer, on the neutralized layer, (3) phase-separating the block copolymer layer, preferably a PS-b-PMMA layer, formed on the neutralized layer, (4) etching the phase-separated block copolymer layer, preferably a PS-b-PMMA layer, and (5) etching the substrate.

[0128] Gases that can be used for etching include, for example, tetrafluoromethane (CF), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride, difluoromethane, nitrogen trifluoride and chlorine trifluoride, chlorine, trichloroborane, and dichloroborane.

[0129] By utilizing the pattern of the vertically phase-separated block copolymer layer, preferably the PS-b-PMMA layer, according to the present invention, it is possible to impart a desired shape to a processing target substrate by etching, thereby fabricating a suitable semiconductor device. [Example]

[0130] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0131] [Example 1] (Preparation of Block Copolymer 1) 0.5 g of a block copolymer, polystyrene / poly(methyl methacrylate) copolymer (manufactured by POLYMER SOURCE INC., PS (Mw: 39,800, Mn: 37,500)-b-PMMA (Mw: 19,100, Mn: 18,000), polydispersity index = 1.06), was dissolved in 24.5 g of propylene glycol monomethyl ether acetate to give a 2% by mass solution, which was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a solution of self-assembled film-forming composition 1 containing block copolymer 1. The weight average molecular weight (Mw) of the polymers shown in the following synthesis examples was measured by gel permeation chromatography (GPC) using a GPC device manufactured by Tosoh Corporation under the following measurement conditions: Measuring device: HLC-8020GPC (product name) (manufactured by Tosoh Corporation) GPC columns: TSKgel G2000HXL (trade name): 2, G3000HXL (trade name): 1, G4000HXL (trade name): 1 (all manufactured by Tosoh Corporation) Column temperature: 40℃ Solvent: tetrahydrofuran (THF) Flow rate: 1.0ml / min Standard sample: Polystyrene (manufactured by Tosoh Corporation)

[0132] (Preparation of Block Copolymer 2) A solution of block copolymer 2 was prepared in the same manner as for block copolymer 1, except that polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 50,200, Mn: 46,100)-b-PMMA (Mw: 22,900, Mn: 21,000), polydispersity index = 1.09) was used instead of polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 39,800, Mn: 37,500)-b-PMMA (Mw: 19,100, Mn: 18,000), polydispersity index = 1.06).

[0133] (Preparation of Block Copolymer 3) A solution of block copolymer 3 was prepared in the same manner as for block copolymer 1, except that polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 59,900, Mn: 55,000)-b-PMMA (Mw: 23,900, Mn: 22,000), polydispersity index = 1.09) was used instead of polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 39,800, Mn: 37,500)-b-PMMA (Mw: 19,100, Mn: 18,000), polydispersity index = 1.06).

[0134] (Preparation of Block Copolymer 4) A solution of block copolymer 4 was prepared in the same manner as for block copolymer 1, except that polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 28,700, Mn: 26,800)-b-PMMA (Mw: 13,100, Mn: 12,200), polydispersity index = 1.09) was used instead of polystyrene / poly(methyl methacrylate) copolymer (POLYMER SOURCE INC., PS (Mw: 39,800, Mn: 37,500)-b-PMMA (Mw: 19,100, Mn: 18,000), polydispersity index = 1.06).

[0135] [Synthesis Example 1] Synthesis of Polymer 1 6.23 g of 2-vinylnaphthalene (85% by molar ratio relative to the total amount of polymer 1), 0.93 g of hydroxyethyl methacrylate (15% by molar ratio relative to the total amount of polymer 1), and 0.36 g of 2,2'-azobisisobutyronitrile were dissolved in 22.50 g of propylene glycol monomethyl ether acetate, and the solution was heated and stirred at 85°C for approximately 24 hours. This reaction solution was added dropwise to methanol, and the precipitate was recovered by suction filtration. Polymer 1 was recovered by drying under reduced pressure at 60°C. The weight average molecular weight Mw measured by GPC in terms of polystyrene was 6,000.

[0136] [Synthesis Example 2] Synthesis of Polymer 2 4.77 g of 2-vinylnaphthalene (60% by molar ratio relative to the total polymer 2), 1.34 g of hydroxyethyl methacrylate (20% by molar ratio relative to the total polymer 2), 1.03 g of methyl methacrylate (20% by molar ratio relative to the total polymer 2), and 0.36 g of 2,2'-azobisisobutyronitrile were dissolved in 22.50 g of propylene glycol monomethyl ether acetate, and the solution was heated and stirred at 85°C for approximately 24 hours. This reaction solution was added dropwise to methanol, and the precipitate was collected by suction filtration. Polymer 2 was then collected by drying under reduced pressure at 60°C. The weight-average molecular weight Mw measured by GPC in terms of polystyrene was 6,000.

[0137] [Synthesis Example 3] Synthesis of Polymer 3 2.57 g of 2-vinylnaphthalene (50% by molar ratio relative to the total polymer 3), 2.06 g of benzyl methacrylate (35% by molar ratio relative to the total polymer 3), 0.72 g of hydroxyethyl methacrylate (15% by molar ratio relative to the total polymer 3), and 0.33 g of 2,2'-azobisisobutyronitrile were dissolved in 22.50 g of propylene glycol monomethyl ether acetate, and the solution was heated and stirred at 85°C for approximately 24 hours. This reaction solution was added dropwise to methanol, and the precipitate was collected by suction filtration. Polymer 3 was then collected by drying under reduced pressure at 60°C. The weight-average molecular weight Mw measured by GPC in terms of polystyrene was 5900.

[0138] [Synthesis Example 4] Synthesis of Polymer 4 6.13 g of 2-vinylnaphthalene (85% molar ratio relative to the total amount of polymer 4), 1.01 g of hydroxypropyl methacrylate (15% molar ratio relative to the total amount of polymer 4), and 0.36 g of 2,2'-azobisisobutyronitrile were dissolved in 22.50 g of propylene glycol monomethyl ether acetate, and the solution was heated and stirred at 85°C for approximately 24 hours. This reaction solution was added dropwise to methanol, and the precipitate was collected by suction filtration. Polymer 4 was then collected by drying under reduced pressure at 60°C. The weight-average molecular weight Mw measured by GPC in terms of polystyrene was 6,200.

[0139] [Synthesis Example 5] Synthesis of Polymer 5 11.00 g of vinylcarbazole (80% by molar ratio to the total amount of polymer 5), 1.85 g of hydroxyethyl methacrylate (20% by molar ratio to the total amount of polymer 5), and 0.39 g of 2,2'-azobisisobutyronitrile were dissolved in 30.89 g of propylene glycol monomethyl ether acetate, and the solution was heated and stirred at 85°C for approximately 19 hours. The weight-average molecular weight Mw of the resulting polymer 5, measured by GPC in terms of polystyrene, was 6,950.

[0140] [Synthesis Example 6] Synthesis of Polymer 6 5.00 g of dicyclopentadiene epoxy resin (product name: EPICLON HP-7200H, manufactured by DIC Corporation), 3.58 g of 4-phenylbenzoic acid, and 0.17 g of ethyltriphenylphosphonium bromide were added to 34.98 g of propylene glycol monomethyl ether, and the mixture was heated under reflux for 16 hours under a nitrogen atmosphere. The weight-average molecular weight Mw of the resulting polymer 6, measured by GPC in terms of polystyrene, was 1,800.

[0141] [Synthesis Example 7] Synthesis of Polymer 7 5.50 g of dicyclopentadiene-type epoxy resin (product name: EPICLON HP-7200H, manufactured by DIC Corporation), 3.54 g of 4-tert-butylbenzoic acid, and 0.18 g of ethyltriphenylphosphonium bromide were added to 36.89 g of propylene glycol monomethyl ether, and the mixture was heated under reflux for 15 hours under a nitrogen atmosphere. The weight-average molecular weight Mw of the resulting polymer 7, measured by GPC in terms of polystyrene, was 2000.

[0142] [Synthesis Example 8] Synthesis of Polymer 8 16.85 g of phenyltrimethoxysilane (85 mol% of total silanes), 3.13 g of tetraethoxysilane (15 mol% of total silanes), and 28.84 g of acetone were placed in a 100 ml flask. While stirring the mixture with a magnetic stirrer, 5.47 g of 0.01 mol / L hydrochloric acid was added dropwise. After the addition, the flask was transferred to an oil bath adjusted to 85 °C and reacted under reflux for 4 hours. The reaction solution was then cooled to room temperature, and 72 g of propylene glycol monomethyl ether acetate was added to the reaction solution. The reaction by-products, methanol, ethanol, water, and hydrochloric acid, were removed under reduced pressure and concentrated to obtain a polymer solution. Propylene glycol monoethyl ether was added to the mixture, and the solvent ratio was adjusted to propylene glycol monomethyl ether acetate / propylene glycol monoethyl ether = 20 / 80. The weight average molecular weight Mw of the obtained polymer 8 was 1,200 as measured by GPC in terms of polystyrene.

[0143] (Preparation of Underlayer Film-Forming Composition 1) 0.39 g of the polymer obtained in Synthesis Example 1 was mixed with 0.10 g of tetramethoxymethyl glycoluril and 0.05 g of pyridinium-p-toluenesulfonate, and 69.65 g of propylene glycol monomethyl ether acetate and 29.37 g of propylene glycol monomethyl ether were added to dissolve the mixture, followed by filtration using a polyethylene microfilter with a pore size of 0.02 μm to prepare a solution of an underlayer film-forming composition for a self-assembled film.

[0144] (Preparation of Underlayer Film-Forming Compositions 2 to 5) Underlayer film-forming compositions 2 to 5 were prepared in the same manner as for preparing underlayer film-forming composition 1, except that the polymer obtained in Synthesis Example 1 was replaced with the polymers obtained in Synthesis Examples 2 to 5, respectively.

[0145] (Preparation of Underlayer Film-Forming Composition 6) 0.26 g of the polymer obtained in Synthesis Example 6 was mixed with 0.07 g of tetramethoxymethyl glycoluril and 0.007 g of pyridinium-p-toluenesulfonate, and 8.90 g of propylene glycol monomethyl ether acetate and 20.76 g of propylene glycol monomethyl ether were added and dissolved, followed by filtration using a polyethylene microfilter with a pore size of 0.02 μm to prepare a solution of underlayer film-forming composition 6 for self-assembled membranes.

[0146] (Preparation of Underlayer Film-Forming Composition 7) Underlayer film-forming composition 7 was prepared in the same manner as in the preparation of underlayer film-forming composition 6, except that the polymer obtained in Synthesis Example 7 was used instead of the polymer obtained in Synthesis Example 6.

[0147] (Preparation of Underlayer Film-Forming Composition 8) 1.33 g of the polymer obtained in Synthesis Example 8 was mixed with 0.006 g of maleic acid and 0.0012 g of benzyltriethylammonium chloride, and 0.68 g of propylene glycol monomethyl ether acetate, 0.79 g of propylene glycol monomethyl ether, 9.10 g of 1-ethoxy-2-propanol, and 1.30 g of ultrapure water were added to dissolve the mixture, and the mixture was then filtered using a fluororesin microfilter with a pore size of 0.1 μm to prepare a solution of underlayer film-forming composition 8 for self-assembled monolayers.

[0148] (Preparation of Underlayer Film-Forming Composition 9 Using Brush Material) 0.3 g of a polystyrene / poly(methyl methacrylate) random copolymer having terminal hydroxyl groups (manufactured by POLYMER SOURCE INC., molar ratio of polystyrene: 80%, molar ratio of poly(methyl methacrylate): 20%, Mw=14,500, polydispersity=1.40) was dissolved in 29.7 g of propylene glycol monomethyl ether acetate to prepare a 1% by mass solution, which was then filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a solution of underlayer film-forming composition 9 using a brush material.

[0149] [Example 2] (Evaluation of self-assembly of block copolymers) The self-assembled monolayer underlayer film-forming composition 1 obtained above was applied to a silicon wafer and heated on a hot plate at 240°C for 1 minute to form a 5-10 nm thick underlayer film (layer A). A self-assembled monolayer-forming composition containing block copolymer 1 was then applied to the silicon wafer using a spin coater and heated on a hot plate at 100°C for 1 minute to form a 40 nm thick self-assembled monolayer (layer B). The wafer coated with this self-assembled monolayer was then heated at 290°C for 15 minutes in an O2 / N2 mixed gas atmosphere (flow ratio: O2:N2 = 2:8) at 760 mTorr using a Lam Research etching system (Lam 2300 MWS) to induce a microphase-separated structure in the self-assembled monolayer.

[0150] (Observation of microphase separation structure) The silicon wafers with induced microphase-separated structures were etched for 3 seconds using a Lam Research etching system (Lam 2300 Versys Kiyo45) with O2 / N2 gas as the etching gas, to preferentially etch the poly(methyl methacrylate) regions. The morphology was then observed using an electron microscope (S-4800, Hitachi High-Technologies).

[0151] [Examples 3 to 5] The microphase-separated structure was observed in the same manner as in Example 2, except that underlayer film-forming compositions 2 to 4 were used instead of underlayer film-forming composition 1.

[0152] [Examples 6 to 7] The microphase-separated structure was observed in the same manner as in Example 2, except that heating was performed in N2 or O2 gas instead of in an O2 / N2 mixed gas atmosphere.

[0153] [Examples 8 to 9] The microphase-separated structure was observed in the same manner as in Example 6, except that heating was performed at 270°C or 300°C instead of 290°C.

[0154] [Examples 10 to 11] The microphase-separated structure was observed in the same manner as in Example 6, except that heating was performed at 50 mTorr and 10,000 mTorr instead of at 760 mTorr.

[0155] [Examples 12 to 13] The microphase-separated structure was observed in the same manner as in Example 6, except that heating was performed at 300°C for 3 or 5 minutes instead of at 290°C for 15 minutes.

[0156] [Example 14] The microphase-separated structure was observed in the same manner as in Example 2, except that instead of heating at 290°C for 15 minutes in an O / N mixed gas atmosphere (mixture ratio of O:N = 2:8 (flow ratio)) at subatmospheric pressure using a Lam Research etching apparatus (Lam 2300 MWS), heating was performed in a nitrogen atmosphere at 760 mTorr using an Ayumi Industries vacuum heating apparatus (VJ-300-S).

[0157] [Examples 15 to 21] The microphase-separated structure was observed in the same manner as in Example 14, except that underlayer film-forming compositions 2 to 8 were used instead of underlayer film-forming composition 1, respectively.

[0158] [Examples 22 to 25] The microphase-separated structure was observed in the same manner as in Example 14, except that heating was performed at 240°C, 260°C, 270°C, or 300°C instead of 290°C.

[0159] [Example 26] The microphase-separated structure was observed in the same manner as in Example 14, except that heating was performed at 320°C for 5 minutes instead of at 290°C for 15 minutes.

[0160] [Examples 27 to 28] The microphase-separated structure was observed in the same manner as in Example 14, except that heating was performed at a pressure of 250 mTorr or 5,000 mTorr instead of 760 mTorr. [Examples 29 to 31] The microphase-separated structures were observed in the same manner as in Example 14, except that solutions of block copolymers 2 to 4 were used instead of the solution of block copolymer 1. [Example 32] The microphase separation structure was observed in the same manner as in Example 14, except that instead of applying underlayer film forming composition 1 to a silicon wafer and heating it on a hot plate at 240°C for 1 minute, an underlayer film was prepared by applying underlayer film forming composition 9 to a silicon wafer, heating it on a hot plate at 200°C for 2 minutes, and then immersing it in propylene glycol monomethyl ether acetate to remove any polymer not adhering to the silicon wafer.

[0161] [Comparative Example 1] The microphase-separated structure was observed in the same manner as in Example 2, except that, instead of heating at 290°C for 15 minutes in an O2 / N2 mixed gas atmosphere at a pressure below atmospheric pressure using a Lam Research etching apparatus (Lam 2300 MWS), heating was performed on a hot plate at 290°C for 15 minutes in an air atmosphere at atmospheric pressure (760,000 mTorr).

[0162] Comparative Example 2 The microphase-separated structure was observed in the same manner as in Comparative Example 1, except that the heating temperature was changed from 290°C to 270°C for 15 minutes.

[0163] Comparative Example 3 The microphase-separated structure was observed in the same manner as in Comparative Example 1, except that heating was performed in an N2 atmosphere instead of an air atmosphere.

[0164] (Confirmation of block copolymer sequence) The alignment of the block copolymers prepared in Examples 2 to 13 and Comparative Examples 1 to 3 was confirmed. The results are shown in Table 1, and examples of the results of electron microscope observation are shown in FIG.

[0165] (Confirmation of block copolymer sequence 2) The sequence of the block copolymers prepared in Examples 14 to 32 was confirmed. The results are shown in Table 2. [Table 1] [Table 2]

[0166] As shown in Tables 1 and 2, the method of the present invention for inducing microphase separation by heating at subatmospheric pressure makes it possible to induce vertical alignment of block copolymers, particularly PS-b-PMMA block copolymers, in the temperature range where directed self-assembly can occur, preferably in the high temperature range (270°C or higher). [Industrial Applicability]

[0167] According to the present invention, it is possible to induce a microphase-separated structure of a layer containing a block copolymer perpendicular to the substrate over the entire surface of a coating film without causing poor alignment of the microphase separation of the block copolymer, which is extremely useful from an industrial perspective.

[0168] The disclosures of Japanese Patent Application No. 2020-091721 (filing date: May 26, 2020) and Japanese Patent Application No. 2020-133320 (filing date: August 5, 2020) are incorporated herein by reference in their entirety. All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing a vertically phase-separated block copolymer layer, comprising: A method for producing a vertically phase-separated block copolymer layer, comprising: forming a block copolymer layer on a substrate; and then heating the substrate at a pressure less than atmospheric pressure, wherein the heating temperature is 270°C or higher.

2. The method for producing a block copolymer layer according to claim 1, wherein the block copolymer is PS-b-PMMA.

3. The method for producing a vertically phase-separated block copolymer layer according to claim 1 or 2, wherein the vertical phase separation comprises cylindrical portions.

4. The method for producing a vertically phase-separated block copolymer layer according to claim 3 , wherein the cylindrical portion comprises PMMA.

5. A method for producing a vertically phase-separated block copolymer layer described in any one of claims 1 to 4, further comprising forming a layer for neutralizing the surface energy of the block copolymer below the block copolymer layer.

6. A method for producing a vertically phase-separated block copolymer layer as described in Claim 5, wherein the neutralization layer contains a polymer having a unit structure derived from an aromatic compound.

7. A method for producing a vertically phase-separated block copolymer layer as described in claim 6, wherein the polymer contains 50 mol% or more of unit structures derived from the aromatic compound relative to the entire polymer.

8. A method for producing a vertically phase-separated block copolymer layer as described in claim 5, wherein the neutralization layer contains a polymer having a unit structure containing an aliphatic polycyclic structure of an aliphatic polycyclic compound in its main chain.

9. A method for producing a vertically phase-separated block copolymer layer as described in claim 5, wherein the neutralization layer contains polysiloxane.

10. A method for producing a vertically phase-separated block copolymer layer described in any one of claims 5 to 7, wherein the neutralization layer comprises a polymer having a reactive substituent at its terminal end.

11. The method for producing a vertically phase-separated block copolymer layer according to claim 1, wherein the subatmospheric pressure is 10,000 to 10 mTorr.

12. A method for producing a vertically phase-separated block copolymer layer described in any one of claims 1 to 10, wherein the gas contained in the atmosphere of pressure less than atmospheric pressure is N 2 gas alone, O 2 gas alone, or an N 2 / O 2 mixed gas of any mixing ratio.

13. A method for manufacturing a semiconductor device, comprising the steps of forming a block copolymer layer on a substrate, heating the substrate at a pressure less than atmospheric pressure, etching the vertically phase-separated block copolymer layer, and etching the substrate, wherein the heating temperature is 270°C or higher.

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