WO2018066716A1

WO2018066716A1 - Pattern formation method and composition

Info

Publication number: WO2018066716A1
Application number: PCT/JP2017/036708
Authority: WO
Inventors: 裕之小松; 岳彦成岡; 雅史堀; 仁視大▲崎▼; 智博小田
Original assignee: Jsr株式会社
Priority date: 2016-10-07
Filing date: 2017-10-10
Publication date: 2018-04-12
Also published as: JP7044976B2; JPWO2018066716A1

Abstract

The present invention pertains to a pattern formation method comprising: a step for forming a basic pattern on a front face side of a substrate; a step for filling, in a recess of the basic pattern, a first composition containing a solvent and a first polymer having at least two blocks; a step for subjecting a filling layer formed in the filling step to phase-separation; a step for partially removing a phase of the filling layer after having undergone phase separation; and a step for etching the substrate using, directly or indirectly, a fine pattern formed in the removal step, wherein the basic pattern formation step comprises a step for forming a resist pattern on the front face side of the substrate, and a step for forming a second polymer layer on at least a lateral surface of the resist pattern and forming a third polymer layer different from the second polymer on at least the front surface of the substrate or the front surface of another layer.

Description

Pattern forming method and composition

The present invention relates to a pattern forming method and a composition.

Today, with the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, there is a demand for pattern miniaturization in the lithography process. In response to such requirements, a phase separation structure formed by self-organization of a block copolymer formed by copolymerization of a monomer having one property and a monomer having a different property from this monomer. A method for forming a finer pattern by using the method has been proposed (see Japanese Patent Application Laid-Open Nos. 2008-149447, 2002-519728, and 2003-218383).

Using such a method, a composition containing a block copolymer is applied to a film on which a hole pattern is formed, and then a concentric cylindrical phase separation structure is formed, and a central phase of the phase separation structure is removed. Therefore, a method for forming a hole pattern having a smaller hole diameter than the above hole pattern has been studied (see US Patent Application Publication No. 2010/0297847).

However, in the above conventional hole pattern forming method, when the pattern is miniaturized and the hole diameter to be formed becomes small, a placement error in which the center position of the hole pattern varies becomes significant, and the residue at the bottom of the hole pattern The formation of a hole pattern with a good shape and arrangement on the substrate by etching or the like from this hole pattern because of the occurrence of defects or the low uniformity of the pattern size indicated by Critical Dimension Uniformity (CDU), etc. Has the disadvantage of becoming difficult.

JP 2008-149447 A JP-T-2002-519728 JP 2003-218383 A US Patent Application Publication No. 2010/0297847

The present invention has been made based on the above-described circumstances, and an object thereof is to provide a pattern forming method and a composition capable of forming a pattern having a good shape and arrangement on a substrate.

The invention made in order to solve the above problems includes a step of forming a basic pattern on the surface side of the substrate directly or via another layer (hereinafter also referred to as a “basic pattern forming step”), and a concave portion of the basic pattern. And a first composition (hereinafter referred to as “[A] polymer”) having at least two blocks and a solvent (hereinafter also referred to as “[S] solvent”). A step of filling the “composition (I)” (hereinafter also referred to as “filling step”) and a step of phase-separating the packed bed formed by the filling step (hereinafter also referred to as “phase separation step”). ), A step of removing a part of the packed bed after the phase separation step (hereinafter also referred to as “removal step”), and a fine pattern formed by the removal step is used directly or indirectly. Step of etching the substrate The basic pattern forming step is a step of forming a resist pattern on the surface side of the substrate (hereinafter also referred to as “resist pattern forming step”), and at least a side surface of the resist pattern. The layer of the second polymer (hereinafter also referred to as “[B] polymer”) (hereinafter also referred to as “[B] polymer layer”) is placed on the surface of at least the substrate or other layer. A step of forming a layer (hereinafter also referred to as “[C] polymer layer”) of a third polymer (hereinafter also referred to as “[C] polymer”) different from the coalescence (hereinafter referred to as “polymer layer forming step”). A pattern forming method (hereinafter also referred to as “pattern forming method (A)”).

Another invention made in order to solve the above-described problem is that a first functional group (hereinafter referred to as “functional group (1) that binds to at least one terminal of the main chain and forms a chemical bond with at least one of —COOH and —OH”. ) ”) And Si—H, Si—OH, Si═O and Si—NR ₂ (R each independently represents a carbon number of 1 to A polymer having a second functional group (hereinafter also referred to as “functional group (2)”) that forms a chemical bond with at least one of 20 monovalent organic groups) and a solvent. .

Still another invention made in order to solve the above problems includes a step of laminating a basic pattern on the surface side of a substrate directly or via another layer (hereinafter also referred to as “basic pattern laminating step”), and the above basic A step of applying a fifth composition (hereinafter, also referred to as “composition (V)”) to the side and bottom surfaces of the concave portions of the pattern (hereinafter, also referred to as “coating step”) and the above-described coating step. A step of heating the coated film (hereinafter also referred to as “heating step”) and a sixth composition (hereinafter also referred to as “composition (VI)”) in the concave portion of the basic pattern on which the coating film is laminated. ), A step of phase-separating the packed bed formed by the filling step (phase separation step), and a step of removing at least a part of the phase of the packed bed after the phase separation step. (Removal step) and formed by the above removal step A pattern forming method comprising a step (etching step) of etching the substrate one or more times using a thinned pattern, wherein the basic pattern comprises a polymer having an aromatic ring content of 50% by mass or more as a main component And a fourth polymer (hereinafter also referred to as “[A ′] polymer”) having the first structural unit (hereinafter also referred to as “structural unit (I)”) and a solvent. A first block (hereinafter also referred to as “block (A)”) comprising the second structural unit (hereinafter also referred to as “structural unit (II)”) and the structural unit (II). ) Having a second block (hereinafter also referred to as “block (B)”) composed of a third structural unit (hereinafter also referred to as “structural unit (III)”) having a higher polarity than that of [B ′] polymer ”) and a solvent. And the difference (| θ1-θ2 |) between the water contact angle θ1 on the side surface of the concave portion of the basic pattern and the water contact angle θ2 on the bottom surface in the coating film after the heating step is 5 ° or more. Is a pattern forming method (hereinafter also referred to as “pattern forming method (B)”).

Here, “chemical bond” is a concept including electrostatic attraction and hydrogen bond between molecules in addition to covalent bond, ionic bond, metal bond and coordination bond.

That is, the pattern forming methods (A) and (B) include a step of forming a basic pattern on the surface side of the substrate directly or via another layer, and a first having at least two blocks in the concave portion of the basic pattern. A step of filling a first composition containing a polymer and a solvent, a step of phase-separating the packed bed formed by the filling step, and removing a part of the phase of the packed bed after the phase separation step. And a step of etching the substrate directly or indirectly using the miniaturized pattern formed by the removing step, wherein the basic pattern has a first layer on at least a side surface of the recess, and the recess The pattern forming method has a second layer having a contact angle different from that of the first layer on the surface side of at least the substrate or other layer.

According to the pattern forming method and composition of the present invention, a pattern having a good shape and arrangement can be formed on a substrate. Therefore, these can be suitably used for lithography processes in manufacturing various electronic devices such as semiconductor devices and liquid crystal devices that are required to be further miniaturized.

It is typical sectional drawing which shows an example of the state after forming the resist pattern in the surface side of a board | substrate. FIG. 2 is a schematic cross-sectional view showing an example of a state after forming a [B] polymer layer and a [C] polymer layer on the side surface of the resist pattern and the surface of the substrate in FIG. 1. It is typical sectional drawing which shows an example after filling the recessed part of the basic pattern in FIG. 2 with composition (I). FIG. 4 is a schematic cross-sectional view illustrating an example of a state after phase separation of the packed bed in FIG. 3. FIG. 5 is a schematic cross-sectional view showing an example of a state after removing a part of the phase of the packed bed after the phase separation step in FIG. 4.

Hereinafter, embodiments of the pattern forming method of the present invention will be described in detail with reference to FIGS.

The pattern forming method includes a pattern forming method (A) and a pattern forming method (B). According to the pattern formation method (A), even when the pattern is fine, it is possible to form a fine pattern in which placement errors are suppressed and bottom residue is reduced. According to the pattern forming method (B), it is possible to form a fine pattern having excellent pattern size uniformity. According to the pattern forming method, a pattern having a good shape and arrangement can be formed on the substrate by using these excellent miniaturized patterns. Hereinafter, the pattern formation method (A) and the pattern formation method (B) will be described.

<Pattern formation method (A)>
The pattern forming method (A) includes a basic pattern forming step, a filling step, a phase separation step, a removing step, and an etching step. In the pattern forming method (A), the basic pattern forming step includes a resist pattern forming step and a polymer layer forming step.

The pattern forming method (A) includes the above steps, and has a resist pattern forming step and a polymer layer forming step in the basic pattern forming step, and at least a side surface of the resist pattern in the polymer layer forming step. By forming the [B] polymer layer and the [C] polymer layer on at least the surface of the substrate or other layer, even if the pattern is fine, placement errors are suppressed and the bottom residue is reduced. A fine pattern can be formed, and by using such an excellent fine pattern, a pattern having a good shape and arrangement can be formed on the substrate. Although the reason why the pattern forming method (A) has the above-described configuration provides the above-described effect is not necessarily clear, for example, it can be inferred as follows. That is, by having a resist pattern forming step and a polymer layer forming step, the [B] polymer layer is placed on the side surface of the resist pattern, that is, the side surface of the concave portion of the basic pattern, and the surface of the substrate or other layer, that is, the basic pattern. By forming the [C] polymer layer on the bottom surface of the recess, different layers are formed on the side surface and the bottom surface of the recess of the basic pattern. It is considered that the layer formed on the side surface and the bottom surface of the recess respectively causes the [A] polymer filling layer formed in the recess to be more appropriately phase-separated, and as a result, the pattern formed is fine. Even in this case, it is possible to form a pattern in which placement errors are suppressed and bottom residue is reduced. Hereinafter, each step will be described.

[Basic pattern formation process]
In this step, a basic pattern (hereinafter also referred to as “basic pattern (I)”) is formed directly on the surface side of the substrate or via another layer. The basic pattern forming step includes a resist pattern forming step and a polymer layer forming step. FIG. 1 shows a case where a resist pattern 2 is formed directly on the surface side of the substrate 1. FIG. 2 shows a case where the polymer layer 3 is formed in the concave portion of the resist pattern 2. In the polymer layer 3 of FIG. 2, the [B] polymer layer is formed on the side surface of the concave portion of the resist pattern, and the [C] polymer layer is formed on the bottom surface of the concave portion. Hereinafter, the process will be described.

As the substrate 1, for example, a conventionally known substrate such as a silicon (Bare-Si) wafer, a silicon substrate such as silicon nitride, or a wafer coated with aluminum can be used. Among these, a silicon substrate is preferable, and a silicon wafer is more preferable.

In addition, examples of other layers include a resist underlayer film, an SOG (Spin On Glass) film, and the like. The SOG film is a silicon-containing film.

Examples of the composition for forming the resist underlayer film include conventionally known organic underlayer film forming materials, and the like, for example, an underlayer film forming composition containing a crosslinking agent.

As the composition for forming the SOG film, a conventionally known SOG composition or the like can be used, and examples thereof include a composition containing an organic polysiloxane. Of these, the SOG film is preferable.

The method for forming the SOG film is not particularly limited. For example, the SOG composition is applied to one surface of the substrate or the surface of the lower layer opposite to the substrate 1 by a known method such as spin coating, and PB The method of hardening | curing the coating film obtained by performing irradiation of a radiation and / or heating after performing is mentioned. Examples of radiation to be irradiated include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays, and γ rays; particle beams such as electron beams, molecular beams, and ion beams. As a minimum of temperature of heating, 100 ° C is preferred, 150 ° C is more preferred, and 180 ° C is still more preferred. As an upper limit of the temperature of heating, 450 degreeC is preferable, 400 degreeC is more preferable, and 350 degreeC is further more preferable. The lower limit of the heating time is preferably 5 seconds, more preferably 10 seconds, and even more preferably 20 seconds. The upper limit of the heating time is preferably 1,200 seconds, more preferably 600 seconds, and even more preferably 300 seconds. The lower limit of the average thickness of the SOG film is preferably 10 nm, more preferably 15 nm, and still more preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm, and still more preferably 100 nm.

The substrate and other layers preferably have at least one of Si—H, Si—OH, Si═O, and Si—NR ₂ on the top surface. Each R is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. “Organic group” refers to a group containing at least one carbon atom. Examples of the monovalent organic group include alkyl groups such as a methyl group and an ethyl group. R is preferably a hydrogen atom. That is, the upper part of the substrate and the other layers is preferably made of SiO ₂ or SiN. When other layers are used, silicon-containing films are preferable as the other layers.

(Resist pattern formation process)
As shown in FIG. 1, the resist pattern 2 may be directly formed on the surface side of the substrate 1, or another layer on the surface side of the substrate 1, for example, a lower layer film, an SOG film or the like on the substrate 1. These films may be formed on the surface opposite to the substrate 1 of these films. Of these, the resist pattern 2 is preferably formed directly on the surface side of the substrate because the pattern can be easily formed on the substrate by etching using the formed resist pattern as a mask.

Examples of the method of forming the resist pattern 2 include a method of forming the resist pattern by coating, exposing and developing a resist composition.

Examples of the resist composition include a resist composition containing a polymer having an acid dissociable group and a radiation sensitive acid generator, a polymer having a crosslinkable group, and a negative resist composition containing a radiation sensitive acid generator. Conventional resist compositions such as those may be mentioned. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as —COOH or —OH and is dissociated by the action of an acid. Examples of the acid dissociable group that substitutes a hydrogen atom of —COOH include a tertiary hydrocarbon group, a t-alkyl group such as a t-butyl group and a t-amyl group, and 1-ethylcyclopentane-1- And 2-alkylbicycloalkane-2-yl group such as 1-alkylcycloalkane-1-yl group such as yl group and 2-methyladamantan-2-yl group.

As a method for forming the resist pattern 2, first, a resist composition is applied to the surface of the substrate 1 or the surface of another layer, and then pre-baked (PB) to form a resist film. Next, exposure is performed through a mask pattern for forming a resist pattern 2 having a desired shape. Examples of radiation used for exposure include ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), electromagnetic waves such as X-rays, and charged particle beams such as electron beams and α rays. Among these, far ultraviolet rays are preferable, ArF excimer laser light and KrF excimer laser light are more preferable, and ArF excimer laser light is more preferable. As an exposure method, immersion exposure can also be performed. It is preferable to perform post-exposure baking (PEB) after exposure. Subsequently, development is performed using a developer such as an alkali developer such as an aqueous 2.38 mass% tetramethylammonium hydroxide solution or an aqueous tetrabutylammonium hydroxide solution, or an organic solvent developer such as butyl acetate or anisole.

The lower limit of the average thickness of the resist film is preferably 10 nm, more preferably 30 nm, and even more preferably 50 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm, and even more preferably 200 nm.

The shape of the resist pattern 2 can be appropriately selected according to the shape of the pattern finally formed on the substrate. For example, in a plan view, the shape is a circle (substantially perfect circle), an ellipse (oval), or a square. , Rectangular shape, bowl shape, trapezoidal shape, triangular shape and the like. Among these, a circular shape is preferable.

When the resist pattern 2 to be formed is circular, the lower limit of the average diameter is preferably 10 nm, more preferably 20 nm, still more preferably 30 nm, and particularly preferably 40 nm. The upper limit of the average diameter is preferably 200 nm, more preferably 100 nm, still more preferably 90 nm, and particularly preferably 80 nm.

The lower limit of the pitch of the resist pattern 2 to be formed is preferably 30 nm, more preferably 50 nm, still more preferably 70 nm, and particularly preferably 90 nm. The upper limit of the pitch is preferably 1,000 nm, more preferably 500 nm, still more preferably 200 nm, and particularly preferably 150 nm.

The resist pattern 2 preferably has at least one of —COOH and —OH on the side surface.

Such a resist pattern 2 having at least one of —COOH and —OH on its side surface is, for example, applied to a resist composition containing a polymer having an acid-dissociable group and a radiation-sensitive acid generator, exposure, and an organic solvent. It can be formed by development with a developer. In addition, after applying a resist composition containing a polymer having an acid-dissociable group and a radiation-sensitive acid generator, exposure and development with an alkali developer, the resulting resist film is heated or exposed. Thus, it can also be formed by dissociating the acid dissociable group in the resist film.

[Polymer layer forming step]
In this step, as shown in FIG. 2, the [B] polymer layer is formed on at least the side surface of the resist pattern 2, and the [C] polymer layer is formed on at least the surface of the substrate or another layer. This step includes a step [B] forming a polymer layer (hereinafter also referred to as “[B] polymer layer forming step”) and a step [C] forming a polymer layer (hereinafter referred to as “[C] These steps may be performed separately or at the same time.

([B] polymer layer forming step)
In this step, a [B] polymer layer is formed on at least the side surface of the resist pattern 2.

[B] As a method for forming a polymer layer, for example, a step of applying a composition (II) containing, for example, a [B] polymer and a solvent (hereinafter also referred to as “[S] solvent”) (hereinafter referred to as “B”). And a method of performing “composition (II) coating step”).

(Composition (II))
The composition (II) contains a [B] polymer and a [S] solvent. The composition (II) may contain other components in addition to the [B] polymer and the [S] solvent.

([B] polymer)
[B] The polymer preferably has a functional group (1) bonded to at least one terminal of the main chain and chemically bonded to at least one of —COOH and —OH. “Main chain” refers to the longest of the atomic chains of a polymer.

Examples of the functional group (1) include a hydroxyl group, an epoxy group (oxiranyl group), and an oxetanyl group. These functional groups form a covalent bond with —COOH and / or —OH.

Examples of the [B] polymer include a styrene polymer, a (meth) acrylic polymer, an ethylene polymer, and a copolymer combining these.

The styrene polymer has a structural unit derived from substituted or unsubstituted styrene.

Examples of the substituted styrene include α-methylstyrene, o-, m-, p-methylstyrene, pt-butylstyrene, 2,4,6-trimethylstyrene, p-methoxystyrene, pt-butoxystyrene, o-, m-, p-vinylstyrene, o-, m-, p-hydroxystyrene, m-, p-chloromethylstyrene, p-chlorostyrene, p-bromostyrene, p-iodostyrene, p-nitrostyrene , P-cyanostyrene and the like.

The (meth) acrylic polymer has a structural unit derived from (meth) acrylic acid or (meth) acrylic acid ester.

Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. ;
Cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 2-ethyladamantyl (meth) acrylate, 2- (adamantan-1-yl) propyl (meth) acrylate, etc. (Meth) acrylic acid cycloalkyl ester of
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and naphthyl (meth) acrylate;
(Meth) acrylic acid-substituted alkyl esters such as 2-hydroxyethyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, 3-glycidylpropyl (meth) acrylate, 3-trimethylsilylpropyl (meth) acrylate, etc. Is mentioned.

The ethylene polymer has a structural unit derived from substituted or unsubstituted ethylene.

Examples of the substituted ethylene include alkenes such as propene, butene, and pentene;
Vinylcycloalkanes such as vinylcyclopentane and vinylcyclohexane;
Cycloalkenes such as cyclopentene and cyclohexene;
Examples include 4-hydroxy-1-butene, vinyl glycidyl ether, vinyl trimethylsilyl ether, and the like.

[B] The lower limit of the weight average molecular weight (Mw) of the polymer is preferably 1,000, more preferably 3,000, still more preferably 5,000, and particularly preferably 5,500. The upper limit of Mw is preferably 100,000, more preferably 50,000, still more preferably 15,000, and particularly preferably 10,000.

[B] The upper limit of the ratio (dispersion degree) of the Mw to the number average molecular weight (Mn) of the polymer is preferably 5, more preferably 3, more preferably 2, and particularly preferably 1.3. The lower limit of the ratio is usually 1 and preferably 1.05.

Mw and Mn in this specification are GPC columns (two "G2000HXL", one "G3000HXL", one "G4000HXL" from Tosoh Corporation), a flow rate of 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration : Measured by gel permeation chromatography (GPC) using a monodisperse polystyrene as a standard using a differential refractometer as a detector under the analysis conditions of 1.0 mass%, sample injection amount: 100 μL, column temperature: 40 ° C. It is a thing.

[B] The lower limit of the content of the polymer is preferably 80% by mass, more preferably 90% by mass, and still more preferably 95% by mass with respect to the total solid content in the composition (II). As an upper limit of the said content, it is 100 mass%, for example. “Total solids” refers to the sum of components other than the [S] solvent.

([S] solvent)
[S] The solvent is not particularly limited as long as it is a solvent that can dissolve or disperse at least the [B] polymer and other components.

[S] Solvents include, for example, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl 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, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Linear ketone solvents such as di-iso-butyl ketone and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Polyhydric alcohol partial ether carbochelate solvents such as ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Lactone solvents such as γ-butyrolactone and valerolactone;
Carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate;
Diethyl acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of hydrocarbon solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

Of these, ester solvents are preferred, polyhydric alcohol partial ether carboxylate solvents are more preferred, and propylene glycol monomethyl ether acetate is even more preferred. Composition (II) may contain one or more [S] solvents.

(Other ingredients)
The composition (II) may contain, for example, a surfactant as other components. Composition (II) can improve the coating property to the resist pattern 2 by containing surfactant.

Examples of the coating method of the composition (II) include a spin coating method.

([C] polymer layer forming step)
In this step, a [C] polymer layer is formed on the surface of at least the substrate or other layer of the resist pattern.

[C] As a method for forming a polymer layer, for example, a step of applying a composition (III) containing a [C] polymer and a [S] solvent (hereinafter referred to as “composition (III) coating step”). And the like.

(Composition (III))
The composition (III) contains a [C] polymer and a [S] solvent. The composition (III) may contain components other than the [C] polymer and the [S] solvent.

([C] polymer)
[C] As the polymer, Si—H, Si—OH, Si═O and Si—NR ₂ bonded to at least one terminal of the main chain (R each independently represents a hydrogen atom or a carbon number of 1 to It is preferable to have a functional group (2) that forms a chemical bond with at least one of 20 monovalent organic groups.

Examples of the functional group (2) include a carboxy group, a hydroxyl group, and a halogen atom. These functional groups form covalent bonds with Si—H, Si—OH, Si═O and / or Si—NR ₂ .

Examples of the [C] polymer include a styrene polymer, a (meth) acrylic polymer, an ethylene polymer, and a copolymer combining these. Examples of these polymers include polymers similar to those exemplified as the [B] polymer.

[C] The lower limit of the weight average molecular weight (Mw) of the polymer is preferably 1,000, more preferably 3,000, still more preferably 4,000, and particularly preferably 5,000. The upper limit of the Mw is preferably 100,000, more preferably 50,000, still more preferably 20,000, and particularly preferably 10,000.

[C] The upper limit of the ratio (dispersion degree) of the Mw to the number average molecular weight (Mn) of the polymer is preferably 5, more preferably 3, more preferably 2, and particularly preferably 1.4. The lower limit of the ratio is usually 1 and preferably 1.1.

[C] The lower limit of the content of the polymer is preferably 80% by mass, more preferably 90% by mass, and still more preferably 95% by mass with respect to the total solid content in the composition (III). As an upper limit of the said content, it is 100 mass%, for example.

Examples of the [S] solvent and other components in the composition (III) include the same as those exemplified as the [S] solvent and other components in the composition (II).

Examples of the coating method of the composition (III) include a spin coating method.

In the polymer layer forming step, when the [B] polymer layer forming step and the [C] polymer layer forming step are simultaneously performed, the [B] polymer, the [C] polymer, and the [S] solvent are added. A step of applying a composition (hereinafter, also referred to as “composition (IV)”) (hereinafter, also referred to as “composition (IV) coating step”) may be performed.

(Composition (IV))
The composition (IV) contains a [B] polymer, a [C] polymer, and a [S] solvent. The composition (IV) may contain components other than the [B] polymer, the [C] polymer, and the [S] solvent.

The [B] polymer, [C] polymer, [S] solvent and other components in the composition (IV) are the same as those exemplified as the [S] solvent and other components in the composition (II). And the like.

The lower limit of the total content of the [B] polymer and the [C] polymer is preferably 80% by mass, more preferably 90% by mass, and 95% by mass with respect to the total solid content in the composition (IV). Further preferred. As an upper limit of the said content, it is 100 mass%, for example.

[Method for synthesizing [B] polymer and [C] polymer]
The [B] polymer and the [C] polymer can be synthesized by polymerization such as anionic polymerization and radical polymerization, but living anionic polymerization in which any terminal structure can be easily introduced is preferable. According to living anionic polymerization, for example, a monomer such as styrene is polymerized, and the polymerization terminal is treated with an arbitrary terminal treating agent to introduce a functional group that is bonded to the terminal of the main chain of the polymer. Can do.

For example, when synthesizing a polymer composed of a polystyrene block having a functional group (1) or a functional group (2) at the terminal, it is first activated by polymerizing styrene in an appropriate solvent using an anionic polymerization initiator. A terminal styrene polymer is formed. Then, the polymer by which the functional group was introduce | transduced into the terminal of the principal chain of a polystyrene can be obtained by processing with the terminal processing agent which gives a functional group (1) or a functional group (2).

That is, examples of the terminal treatment method include a method as shown in the following scheme. That is, a terminal treatment agent such as 1,2-butylene oxide is added to the active terminal during polymerization to modify the terminal to obtain a polymer having a functional group bonded to the terminal of the main chain.

In the above scheme, n and m are integers of 10 to 5,000.

Examples of the terminal treatment agent that gives a hydroxyl group include epoxy compounds such as 1,2-butylene oxide, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, propylene oxide, ethylene oxide, styrene oxide, and epoxyamine.

Examples of the end treatment agent that gives a carboxy group include carbon dioxide.

Examples of the end treatment agent that gives an epoxy group include halogen atom-containing epoxy compounds such as epibromohydrin and epichlorohydrin.

Examples of the end treating agent that gives an oxetanyl group include halogen atom-containing oxetane compounds such as 3-chloromethyl-3-methyloxetane and 3-chloromethyl-3-ethyloxetane.

In addition, a polymer having a carboxy group at the terminal is, for example, a monomer such as styrene and methyl 4-cyano-4-[(dodecylsulfanylthiocarbonylsulfane) pentanoate or the like in a solvent such as anisole. It can be obtained by performing polymerization (Reversible Addition Fragmentation Chain Transfer Polymerization, reversible addition-fragmentation chain transfer polymerization).

The polymer having a halogen atom at the terminal is prepared by charging a monomer such as styrene, an amine compound such as copper (II) bromide and tris [(2-dimethylamino) ethyl] amine, and a solvent such as anisole. Further, it can be synthesized by atom transfer radical polymerization by adding a halogen compound such as 2-hydroxyethyl 2-bromoisobutyrate to this.

The [B] polymer and [C] polymer obtained above are preferably recovered by a reprecipitation method. That is, after completion of the terminal treatment reaction, the target copolymer is recovered as a powder by introducing the reaction solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like. The [B] polymer and the [C] polymer are preferably subjected to purification such as demetallation with an acid or the like.

[Method for Preparing Compositions (II) to (IV)]
In the compositions (II) to (IV), for example, the [B] polymer and / or the [C] polymer, the [S] solvent and other components as necessary are mixed at a predetermined ratio, and preferably the pore size is 0. It can be prepared by filtering with a high-density polyethylene filter of about 45 μm. The lower limit of the solid content concentration of the compositions (II) to (IV) is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 0.7% by mass. The upper limit of the solid content concentration is preferably 30% by mass, more preferably 10% by mass, and still more preferably 3% by mass.

(Order of each process in the basic pattern formation process)
When the basic pattern forming step includes a resist pattern forming step, a [B] polymer layer forming step, and a [C] polymer layer forming step, these steps can be performed in various orders as described below. . That is, the basic pattern forming step includes, for example: (1) resist pattern forming step, [B] polymer layer forming step, [C] polymer layer forming step in order (2) resist pattern forming step, [C] polymer layer (3) [C] Polymer layer forming step, resist pattern forming step, [B] polymer layer forming step, etc. Among these, the above (1) and (3) are preferable from the viewpoint of more reliably forming the [B] polymer layer and the [C] polymer layer.

When the basic pattern forming step includes a resist pattern forming step, a composition (II) coating step, and a composition (III) coating step, the order of performing these steps is, for example, (A) Resist pattern forming step The order of the composition (II) coating process, the composition (III) coating process (B) The resist pattern formation process, the composition (III) coating process, the order of the composition (II) coating process (C) The composition (III) coating step, the resist pattern forming step, the composition (II) coating step, and the like can be performed in this order. Among these, the above (A) and (C) are preferable from the viewpoint of more reliably forming the [B] polymer layer and the [C] polymer layer.

In the basic pattern forming step, when performing the composition (IV) coating step, the resist pattern forming step is performed from the viewpoint of more reliably forming the [B] polymer layer and the [C] polymer layer. It is preferable to perform a composition (IV) coating process later.

[Filling process]
In this step, the concave portion of the basic pattern (I) is filled with the composition (I) containing [A] a polymer and a solvent.

(Composition (I))
The composition (I) contains a [A] polymer and a solvent. The composition (I) can contain other components in addition to the [A] polymer and the solvent.

([A] polymer)
[A] The polymer is a polymer having at least two blocks. That is, the [A] polymer is a block copolymer.

[A] The polymer may be a diblock copolymer, a triblock copolymer, or a copolymer having four or more blocks. Among these, from the viewpoint of easy formation of the phase separation structure, a diblock copolymer and a triblock copolymer are preferable, and a diblock copolymer is more preferable. [A] The polymer may have a linking group between adjacent blocks.

[A] When the polymer is a diblock copolymer, it has a block (I) and a block (II). In the block (II), the polarity of the structural unit constituting the block (I) is higher.

(Block (I))
Examples of the block (I) include a polystyrene block. The polystyrene block is a block containing a structural unit derived from substituted or unsubstituted styrene. Among these, a block containing a structural unit derived from styrene is preferable.

(Block (II))
Examples of the block (II) include a poly (meth) acrylic acid ester block, a polyalkylene glycol block, a polyester block, a polyalkylene carbonate block, a polydialkylsiloxane block, and a poly (meth) acrylic acid alkylsilyl ester block. . The poly (meth) acrylate block is a block including a structural unit derived from (meth) acrylate. Among these, a poly (meth) acrylate block is preferable, a poly (meth) acrylate block is more preferable, a poly (meth) acrylate block is more preferable, and a polymethyl methacrylate block is particularly preferable.

(Linking group)
Examples of the linking group include a divalent organic group having 1 to 50 carbon atoms. Examples of the monomer that gives a linking group include diphenylethylene and stilbene. When diphenylethylene and stilbene synthesize the [A] polymer by anionic polymerization, the anion terminal produced in the middle can be stabilized. Thereby, the degree of dispersion (Mw / Mn ratio) of the obtained [A] polymer becomes smaller, and as a result, the variation in the dimension of the formed pattern can be made smaller. [A] The polymer may have one or more linking groups depending on the number of blocks, the target pattern shape, and the like.

[A] The lower limit of the weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC) is preferably 1,000, more preferably 10,000, and even more preferably 50,000. The upper limit of Mw is preferably 300,000, more preferably 200,000, and even more preferably 100,000. [A] By setting the Mw of the polymer in the above range, a contact hole pattern in which placement errors are further suppressed and bottom residue is further reduced can be formed.

[A] The upper limit of the ratio (Mw / Mn, dispersity) between the polymer Mw and the number average molecular weight (Mn) is preferably 5, more preferably 3, more preferably 2, and particularly preferably 1.5. 1.1 is more particularly preferable. The lower limit of the above ratio is usually 1 and preferably 1.01. By setting the Mw / Mn ratio in the above range, it is possible to form a contact hole pattern in which placement errors are further suppressed and bottom residue is further reduced.

[A] The lower limit of the content of the polymer is preferably 80% by mass, more preferably 90% by mass, still more preferably 95% by mass, and 99% by mass with respect to the total solid content in the composition (I). Particularly preferred. The “total solid content” of the composition (I) refers to the sum of components other than the solvent.

The lower limit of the concentration of the [A] polymer in the composition (I) is preferably 0.3% by mass, more preferably 0.7% by mass, further preferably 1.0% by mass, and 1.3% by mass. Is particularly preferred. On the other hand, the upper limit of the concentration is preferably 5% by mass, more preferably 3% by mass, still more preferably 2% by mass, and particularly preferably 1.7% by mass.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized by living anion polymerization, living radical polymerization or the like, but living anion polymerization is more preferable. For example, a polystyrene block, a polymethyl methacrylate block, and other blocks other than these can be linked while polymerizing in a desired order, and the polymerization terminal can be synthesized by treating with an arbitrary terminal treating agent.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloaliphatic hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. These solvents may be used alone or in combination of two or more.

The reaction temperature in the above polymerization may be appropriately determined according to the type of initiator, but the lower limit of the reaction temperature is preferably −150 ° C., more preferably −80 ° C. As an upper limit of the said reaction temperature, 50 degreeC is preferable and 40 degreeC is more preferable. As a minimum of reaction time, 5 minutes are preferred and 20 minutes are more preferred. The upper limit of the reaction time is preferably 24 hours, and more preferably 12 hours.

Examples of the initiator used for the polymerization include alkyl lithium, alkyl magnesium halide, sodium naphthalene, alkylated lanthanoid compounds, and the like. Among these, when polymerizing using styrene, methyl methacrylate or the like as a monomer, it is preferable to use an alkyl lithium compound.

As the above-mentioned end treatment method, an end treatment agent such as an alcohol such as methanol or an epoxy compound such as 2-ethylhexyl glycidyl ether is added to modify the end of the chain during the polymerization reaction. Coalescence can be obtained. The obtained block copolymer is preferably subjected to purification such as demetallation.

<Phase separation process>
In this step, the packed bed 4 formed by the above filling step is phase-separated. As a result, as shown in FIG. 4, the packed bed 4 is phase-separated into a block (α) phase 4a and a block (β) phase 4b.

As a method for phase-separating the packed bed 4, for example, an annealing method or the like can be given.

Examples of the annealing method include a heating method. Examples of the heating means include an oven and a hot plate. As a minimum of the temperature of heating, 80 ° C is preferred, 100 ° C is more preferred, and 150 ° C is still more preferred. As an upper limit of the temperature of heating, 400 degreeC is preferable, 350 degreeC is more preferable, and 300 degreeC is further more preferable. The lower limit of the heating time is preferably 10 seconds, more preferably 1 minute, and even more preferably 10 minutes. The upper limit of the heating time is preferably 120 minutes, more preferably 60 minutes, and even more preferably 30 minutes.

[Removal process]
In this step, a part of the phase of the packed bed after the phase separation step is removed. For example, the block (β) phase 4b, which is one phase of the packed layer after the phase separation step in FIG. 4, is removed, and as shown in FIG. 5, the resist pattern 2, the polymer layer 3, and the packed layer 4a that has not been removed. A miniaturized pattern is formed.

In the removing step, for example, as shown in FIG. 4, a part of the block (β) phase 4b in the phase separation structure of the packed bed 4 is removed. For example, the polymethyl methacrylate block phase 4b can be removed by etching using the difference in the etching rate of each phase separated. FIG. 5 shows a state after the polymethyl methacrylate block phase 4b in the phase separation structure is removed. In addition, you may irradiate a radiation before the said etching process as needed. As the radiation, when the phase to be removed by etching is a polymethyl methacrylate block phase, 172 nm radiation can be used. Since the polymethyl methacrylate block phase is decomposed by the radiation irradiation, etching becomes easier.

Examples of a method for removing the polymethyl methacrylate block phase 4b in the phase separation structure include reactive ion etching (RIE) such as chemical dry etching and chemical wet etching; physical etching such as sputter etching and ion beam etching. There are known methods. Among these, reactive ion etching is preferable, chemical dry etching using CF ₄ , O ₂ gas, etc., and chemical wet etching (wet development) using a liquid etching solution such as an organic solvent or hydrofluoric acid is more preferable. Chemical wet etching is more preferable.

Examples of organic solvents used for chemical wet etching include alkanes such as n-pentane, n-hexane, and n-heptane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), methyl n-pentyl ketone;
Examples include alcohols such as methanol, ethanol, 1-propanol, isopropanol (IPA), and 4-methyl-2-pentanol. These solvents may be used alone or in combination of two or more. Among these, a mixed solvent with MIBK and IPA is preferable.

[Etching process]
In this step, the substrate is etched by directly or indirectly using the miniaturized pattern formed in the removing step. As shown in FIG. 5, the miniaturized pattern is formed of the basic pattern (I) 2, the polymer layer 3, and the block (α) phase that has not been removed in the removing step. By this step, a substrate pattern is formed. According to the pattern formation method (A), it is possible to obtain a substrate pattern in which a placement error is suppressed and the shape is good.

In this etching, when the basic pattern (I) 2 is directly formed on the surface side of the substrate 1 in the basic pattern forming step, the fine pattern is usually used directly, that is, the etching is performed once to form the substrate pattern. obtain. When the basic pattern (I) is formed on the surface side of the substrate 1 through another layer, the fine pattern is usually used indirectly, that is, the fine pattern is used to etch other layers, Etching is sequentially performed using the other layers after etching as a mask, that is, etching is performed a plurality of times to obtain a substrate pattern.

Examples of the substrate pattern to be obtained include a hole pattern.

As an etching method, for example, CF ₄ , O ₂ gas or the like is used, chemical dry etching using a difference in etching rate of each layer or the like, chemical wet etching using a liquid etching solution such as an organic solvent or hydrofluoric acid (wet type). There are known methods such as reactive ion etching (RIE) such as development) and physical etching such as sputter etching and ion beam etching. Among these, reactive ion etching is preferable, chemical dry etching and chemical wet etching are more preferable, and chemical dry etching is more preferable.

After completion of the patterning of the substrate, the portion used as a mask is removed from the surface side of the substrate by dissolution treatment or the like, and a substrate on which a pattern is finally formed can be obtained. The substrate obtained by the pattern forming method (A) is suitably used for a semiconductor element and the like, and this semiconductor element is widely used for LEDs, solar cells and the like.

<Pattern formation method (B)>
The pattern forming method (B) includes a basic pattern lamination step, a coating step, a heating step, a filling step, a phase separation step, a removal step, and an etching step.

The pattern formation method (B) comprises the above steps, and the pattern size is uniform by setting the difference in the contact angle between the side surface and the bottom surface of the concave portion of the basic pattern in the coating film after the heating step to the above value or more. A fine pattern having excellent properties can be formed, and by using such an excellent fine pattern, a pattern having a favorable shape and arrangement can be formed on the substrate. Although the reason why the pattern forming method (B) has the above-described configuration provides the above effect is not necessarily clear, it can be inferred as follows, for example. That is, since the side surface side and the bottom surface side of the concave portion of the basic pattern after the heating step have a difference in contact angle of the above value or more, the packed layer of [A ′] polymer formed in the concave portion after that is more It is considered that the phases are appropriately separated, and as a result, a miniaturized pattern having excellent pattern size uniformity can be formed. Hereinafter, each step will be described.

[Basic pattern lamination process]
In this step, a basic pattern (hereinafter also referred to as “basic pattern (II)”) is laminated directly or via another layer on the surface side of the substrate. As basic pattern (II), what is directly laminated | stacked on a board | substrate is preferable. This basic pattern (II) is mainly composed of a polymer having an aromatic ring content of 50% by mass or more. As a thing which has as a main component the polymer whose content rate of an aromatic ring is 50 mass% or more, a resist underlayer film etc. are mentioned, for example.

Examples of the method of laminating the basic pattern (II) include the following methods. A resist underlayer film is formed on the surface side of the substrate directly or via another layer. Next, if necessary, an SOG film may be formed on the surface of the resist underlayer film opposite to the substrate. A resist pattern is formed on the surface of the resist underlayer film or SOG film opposite to the substrate. Next, the SOG film and / or the resist underlayer film are sequentially etched using the resist pattern as a mask.

Examples of methods for forming the substrate, other layers, the resist underlayer film, the SOG film, and the resist pattern include those similar to those exemplified in the basic pattern forming step of the pattern forming method (A). The substrate is preferably made of silicon.

[Coating process]
In this step, the composition (V) is applied to the side surface and the bottom surface of the concave portion of the basic pattern (II).

(Composition (V))
The composition (V) contains a [A ′] polymer and a solvent ([S] solvent). The composition (V) may contain other components such as a surfactant in addition to the [A ′] polymer and the [S] solvent.

([A '] polymer)
[A ′] The polymer has the structural unit (I). As the structural unit (I), for example, a structural unit derived from substituted or unsubstituted styrene, a structural unit derived from (meth) acrylic acid or (meth) acrylic acid ester, or a structural unit derived from substituted or unsubstituted ethylene Etc. Examples of the substituted or unsubstituted styrene, (meth) acrylic acid ester, and substituted or unsubstituted ethylene include the same as those exemplified in the [B] polymer of the pattern forming method (A).

[A ′] The polymer preferably has a functional group that is bonded to at least one end of the main chain and chemically bonds to at least one of —COOH and —OH. Examples of such functional groups include the functional groups exemplified as the functional group (1) of the [B] polymer in the pattern forming method (A).

[A ′] Mw and Mw / Mn of the polymer, and a preferable range of the content of [A ′] polymer in the composition (V) include the [B] polymer and the composition in the pattern forming method (A). Same as (II).

Examples of the [S] solvent include the same solvents as those exemplified as the [S] solvent of the composition (II) in the pattern formation method (A).

[Method for Preparing Composition (V)]
The composition (V) is prepared, for example, by mixing the [A ′] polymer, the [S] solvent, and other components as necessary at a predetermined ratio, and preferably filtering through a membrane filter having a pore diameter of about 200 nm. can do. As a minimum of solid content concentration of composition (V), 0.1 mass% is preferred, 0.5 mass% is more preferred, and 0.7 mass% is still more preferred. The upper limit of the solid content concentration is preferably 30% by mass, more preferably 10% by mass, and still more preferably 3% by mass.

Examples of the coating method of the composition (V) include a spin coating method.

[Heating process]
In this step, the coating film formed by the coating step is heated. Means the absolute value of the difference (| θ1−θ2 |, (θ1−θ2)) between the water contact angle θ1 on the side surface of the concave portion of the basic pattern in the coated film after the heating step and the water contact angle θ2 on the bottom surface side. Is 5 ° or more. At this time, either of the values of θ1 and θ2 may be larger.

The lower limit of the difference between θ1 and θ2 is preferably 7 ° and more preferably 10 °. The upper limit of the difference between θ1 and θ2 is, for example, 30 °.

The lower limit of θ1 is preferably 50 °, more preferably 80 °. The upper limit of θ1 is preferably 90 ° and more preferably 88 °. The lower limit of θ2 is preferably 60 °, and more preferably 70 °. The upper limit of θ2 is preferably 85 ° and more preferably 80 °.

Examples of the heating means include an oven and a hot plate.

In the heating step, the temperature or time is controlled so that the difference between θ1 and θ2 is greater than or equal to the above value. The temperature and time in the heating step vary depending on, for example, the type of functional group of the [A ′] polymer of the composition (V).

The lower limit of the heating temperature is preferably 50 ° C, more preferably 100 ° C, further preferably 120 ° C, and particularly preferably 140 ° C. As an upper limit of the said temperature, 250 degreeC is preferable, 200 degreeC is more preferable, 180 degreeC is further more preferable, and 160 degreeC is especially preferable.

The lower limit of the heating time is preferably 10 seconds, more preferably 1 minute, further preferably 5 minutes, and particularly preferably 10 minutes. The upper limit of the time is preferably 10 hours, more preferably 1 hour, still more preferably 30 minutes, and particularly preferably 20 minutes.

[Filling process]
In this step, the concave portion of the basic pattern on which the coating film is laminated is filled with the composition (VI).

(Composition (VI))
The composition (VI) contains a [B ′] polymer and a solvent ([S] solvent). The composition (VI) can contain other components in addition to the [B ′] polymer and the [S] solvent.

([B ′] polymer)
[B ′] The polymer has a block (A) and a block (B). That is, the [B ′] polymer is a block copolymer. The block (A) is composed of the structural unit (II), and the block (B) is composed of the structural unit (III) having a higher polarity than the structural unit (II). [B ′] The polymer may be a diblock copolymer, a triblock copolymer, or a copolymer having four or more blocks. Among these, from the viewpoint of easy formation of the phase separation structure, a diblock copolymer and a triblock copolymer are preferable, and a diblock copolymer is more preferable. Moreover, the [B ′] polymer may have a linking group between adjacent blocks.

The block (A) is preferably a polystyrene block exemplified as the block (I) of the [A] polymer in the pattern formation method (A). That is, as the structural unit (II), a structural unit derived from substituted or unsubstituted styrene is preferable. Examples of the block (B) include the blocks exemplified as the block (II) of the [A] polymer. As the block (B), a poly (meth) acrylate block is preferable, and a polymethyl methacrylate block is more preferable. As the structural unit (III), a structural unit derived from a (meth) acrylic acid ester is preferable.

[B ′] Mw and Mw / Mn of the polymer, and the content and concentration of the [B ′] polymer in the composition (VI) are the [A] polymer and the composition of the pattern formation method (A) ( A range similar to that in I) is preferred.

[Phase separation process]
In this step, the packed bed formed by the above filling step is phase-separated. This step is the same as the phase separation step in the pattern forming method (A).

[Removal process]
In this step, at least a part of the phase of the packed bed after the phase separation step is removed. This step is the same as the removing step in the pattern forming method (A).

[Etching process]
In this step, the substrate is etched one or more times using the miniaturized pattern formed in the removing step. This step is the same as the etching step in the pattern forming method (A).

<Composition>
The composition includes a polymer having a functional group bonded to at least one end of the main chain and forming a chemical bond with at least one of —COOH and —OH, and bonded to at least one end of the main chain. , Si—OH, Si═O, and Si—NR ₂ (wherein R is each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms) that forms a chemical bond. A polymer having a group and a solvent are contained.

The composition is described as the composition (II) used in the pattern formation method (A).

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measuring method of each physical property value is shown below.

[Mw and Mn]
Mw and Mn of the polymer are measured by gel permeation chromatography (GPC) using Tosoh's GPC columns ("G2000HXL", "G3000HXL" and "G4000HXL") under the following conditions. did.
Eluent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[ ¹ H-NMR analysis]
¹ H-NMR analysis was performed using a nuclear magnetic resonance apparatus (“JNM-EX400” manufactured by JEOL Ltd.) and DMSO-d ₆ as a measurement solvent. The content ratio of each structural unit in the polymer was calculated from the area ratio of the peak corresponding to each structural unit in the spectrum obtained by ¹ H-NMR.

<Pattern formation method (A)>
<[A] Synthesis of polymer>
[Synthesis Example 1-1] (Synthesis of Polymer (a-1))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran (THF) that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to -78 ° C. Thereafter, 0.29 mL (0.256 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and thereafter, adsorption filtration with silica gel and distillation dehydration were performed to remove the polymerization inhibitor. 22.7 mL (0.197 mol) of styrene was added dropwise over 30 minutes, and the polymerization system was confirmed to be orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.11 mL (0.00077 mol) of 1,1-diphenylethylene and 1.02 mL (0.0005 mol) of 0.5N THF solution of lithium chloride were added to make the polymerization system dark red. I confirmed. Further, 10.6 mL (0.100 mol) of methyl methacrylate, which has been subjected to adsorption filtration with silica gel for removal of the polymerization inhibitor and distilled and dehydrated, is dropped into this solution over 30 minutes to make the polymerization system light yellow. After confirming that the reaction had occurred, the reaction was continued for 120 minutes. Thereafter, 1 mL of methanol as a terminal terminator was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. Next, 500 g of cyclohexane was poured to remove the polystyrene homopolymer, and the polymer was washed by dissolving the polystyrene homopolymer in cyclohexane. This washing was repeated 4 times, and the solid was collected again with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 24.1 g of a white polymer (a-1).

This polymer (a-1) had Mw of 79,000, Mn of 77,000, and Mw / Mn of 1.03. As a result of ¹ H-NMR analysis, the polymer (a-1) contained 65 mol% and 35 mol% of structural units derived from styrene and structural units derived from methyl methacrylate, respectively. . The polymer (a-1) is a diblock copolymer.

[Synthesis Example 1-2] (Synthesis of Polymer (a-2))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.29 mL (0.256 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and thereafter, adsorption filtration with silica gel and distillation dehydration were performed to remove the polymerization inhibitor. 22.7 mL (0.197 mol) of styrene was added dropwise over 30 minutes, and the polymerization system was confirmed to be orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.11 mL (0.00077 mol) of 1,1-diphenylethylene and 1.02 mL (0.0005 mol) of 0.5N tetrahydrofuran solution of lithium chloride were added to make the polymerization system dark red. I confirmed. Further, 10.6 mL (0.100 mol) of methyl methacrylate, which has been subjected to adsorption filtration with silica gel for removal of the polymerization inhibitor and distilled and dehydrated, is dropped into this solution over 30 minutes to make the polymerization system light yellow. After confirming that the reaction had occurred, the reaction was continued for 120 minutes. Thereafter, 0.053 mL (0.256 mmol) of 2-ethylhexyl glycidyl ether was added as a terminal terminator, and then 1 mL of methanol was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. Next, 500 g of cyclohexane was poured to remove the polystyrene homopolymer, and the polymer was washed by dissolving the polystyrene homopolymer in cyclohexane. This washing was repeated 4 times, and the solid was collected again with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 24.1 g of a white polymer (a-2).

This polymer (a-2) had Mw of 78,000, Mn of 76,000, and Mw / Mn of 1.03. As a result of ¹ H-NMR analysis, the polymer (A-2) contained 65 mol% and 35 mol% of structural units derived from styrene and structural units derived from methyl methacrylate, respectively. . The polymer (a-2) is a diblock copolymer.

[Synthesis Example 1-3] (Synthesis of Polymer (a-3))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.28 mL (0.256 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and then, adsorption removal with silica gel and distillation dehydration were performed to remove the polymerization inhibitor. Styrene 26.0 mL (0.226 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.11 mL (0.00077 mol) of 1,1-diphenylethylene and 1.02 mL (0.0005 mol) of 0.5N tetrahydrofuran solution of lithium chloride were added, and the polymerization system was dark red It was confirmed that it became. Further, 9.5 mL (0.899 mol) of methyl methacrylate, which has been subjected to adsorption filtration with silica gel and distillation dehydration treatment for removing the polymerization inhibitor, was dropped into this solution over 30 minutes to make the polymerization system light yellow. After confirming that the reaction had occurred, the reaction was continued for 120 minutes. Thereafter, 1 mL of methanol as a terminal terminator was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. Next, 500 g of cyclohexane was poured to remove the polystyrene homopolymer, and the polymer was washed by dissolving the polystyrene homopolymer in cyclohexane. This washing was repeated 4 times, and the solid was collected again with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 23.8 g of a white polymer (a-3).

This polymer (a-3) had Mw of 77,000, Mn of 75,000, and Mw / Mn of 1.03. As a result of ¹ H-NMR analysis, the polymer (a-3) was found to contain 70 mol% and 30 mol% of structural units derived from styrene and methyl methacrylate, respectively. . The block copolymer (a-3) is a diblock copolymer.

<[B] Synthesis of polymer>
[Synthesis Example 1-4] (Synthesis of polymer (b-1))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 2.38 mL (2.31 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and thereafter, adsorption filtration with silica gel and distillation dehydration were performed to remove the polymerization inhibitor. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 1 mL of methanol was injected as a terminal terminator to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.7 g of a white polymer (b-1).

This polymer (b-1) had Mw of 5,600, Mn of 5,300, and Mw / Mn of 1.06.

[Synthesis Example 1-5] (Synthesis of Polymer (b-2))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. After that, 2.38 mL (2.30 mmol) of 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and then subjected to adsorption filtration with silica gel and distillation dehydration treatment to remove the polymerization inhibitor. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.27 mL (2.30 mmol) of styrene oxide as a terminal terminator and then 1 mL of methanol were injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.7 g of a white polymer (b-2).

This block copolymer (b-2) had Mw of 5,500, Mn of 5,100, and Mw / Mn of 1.08.

[Synthesis Example 1-6] (Synthesis of Polymer (b-3))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. After that, 2.38 mL (2.30 mmol) of 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and then subjected to adsorption filtration with silica gel and distillation dehydration treatment to remove the polymerization inhibitor. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, carbon dioxide was bubbled as a terminal terminator, and then 1 mL of methanol was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.3 g of a white polymer (b-3).

This polymer (b-3) had Mw of 5,200, Mn of 5,000, and Mw / Mn of 1.04.

[Synthesis Example 1-7] (Synthesis of Polymer (b-4))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 2.38 mL (2.30 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this THF, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.19 mL (2.30 mmol) of epibromohydrin was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.1 g of a white polymer (b-4).

This polymer (b-4) had Mw of 5,700, Mn of 5,200, and Mw / Mn of 1.10.

[Synthesis Example 1-8] (Synthesis of polymer (b-5))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 3.95 mL (3.84 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and then subjected to adsorption filtration with silica gel and distillation dehydration to remove the polymerization inhibitor. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.32 mL (3.84 mmol) of epibromohydrin was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.1 g of a white polymer (b-5).

This polymer (b-5) had Mw of 3,300, Mn of 3,100, and Mw / Mn of 1.06.

[Synthesis Example 1-9] (Synthesis of polymer (b-6))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 1.19 mL (1.15 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into this THF, and then, adsorption removal with silica gel and distillation dehydration were performed to remove the polymerization inhibitor. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.10 mL (1.15 mmol) of epibromohydrin was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.5 g of a white polymer (b-6).

This block copolymer (b-6) had an Mw of 11,600, an Mn of 10,400, and an Mw / Mn of 1.12.

[Synthesis Example 1-10] (Synthesis of Polymer (b-7))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 2.38 mL (2.30 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this THF, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. 13.3 mL (0.115 mol) of styrene was added dropwise over 30 minutes 6 and it was confirmed that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.25 mL (2.30 mmol) of 3-chloromethyl-3-methyloxetane was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 11.1 g of a white block copolymer (b-7).

This block copolymer (b-7) had Mw of 5,900, Mn of 5,300, and Mw / Mn of 1.11.

[Synthesis Example 1-11] (Synthesis of polymer (b-8))
After drying the 500 mL flask reaction vessel under reduced pressure, 120 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 2.38 mL (2.30 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this THF, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. The resulting 4-t-butylstyrene 21.2 mL (0.115 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.19 mL (2.30 mmol) of epibromohydrin was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated three times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained solid was dried under reduced pressure at 60 ° C. to obtain 17.7 g of a white polymer (b-8).

This block copolymer (b-8) had Mw of 6,000, Mn of 5,400, and Mw / Mn of 1.11.

<Synthesis of [C] polymer>
[Synthesis Example 1-12] (Synthesis of Polymer (c-1))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, anisole 40 g, styrene 16.7 g (0.160 mol), methyl methacrylate 3.00 g (0.030 mol), 2-hydroxyethyl methacrylate 1.30 g ( 0.01 mol), 0.29 g (2.00 mmol) of copper (II) bromide and 0.46 g (2 mmol) of tris [(2-dimethylamino) ethyl] amine were added, and the mixture was heated to 100 ° C. to give 2-bromoisobutyric acid. Ethyl 0.53 mL (3.6 mmol) was added, and the mixture was heated and stirred for 8 hours under a nitrogen flow. The obtained polymerization reaction liquid was filtered through Celite to remove the copper complex, and washing with 500 g of ultrapure water was repeated three times. The organic layer was collected and then concentrated, and 50 g of THF added to the resulting concentrate was added to 1,000 g of methanol / ultra pure water (mass ratio = 5/5) to obtain a precipitated and purified solid. . This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained solid was dried under reduced pressure to obtain 11.2 g of a white polymer (c-1).

This polymer (c-1) had Mw of 5,600, Mn of 4,600, and Mw / Mn of 1.22. As a result of ¹ H-NMR analysis, the content ratios of structural units derived from styrene, methyl methacrylate and 2-hydroxyethyl methacrylate were 80 mol%, 15 mol% and 5 mol%, respectively.

[Synthesis Example 1-13] (Synthesis of polymer (c-2))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel 0 and a thermometer, anisole 40 g, styrene 16.7 g (0.160 mol), methyl methacrylate 3.00 g (0.030 mol), methacrylic acid 0.86 g (0.01 mol) ), 0.29 g (2.00 mmol) of copper (II) bromide and 0.46 g (2 mmol) of tris [(2-dimethylamino) ethyl] amine, and heated to 100 ° C. 53 mL (3.6 mmol) was added, and the mixture was heated and stirred for 8 hours under a nitrogen flow. The obtained polymerization reaction liquid was filtered through Celite to remove the copper complex, and washing with 500 g of ultrapure water was repeated three times. After collecting the organic layer, it was concentrated, and the resulting concentrate with 50 g of THF added to 1,000 g of methanol / ultra pure water (mass ratio 5/5) was precipitated and purified to precipitate the polymer. This white solid was dissolved in 50 g of tetrahydrofuran, 5 g of 1N hydrochloric acid aqueous solution was added, and the mixture was heated and stirred at 80 ° C. for 2 hours to conduct a hydrolysis reaction. The reaction solution after hydrolysis was added to 1,000 g of methanol / ultra pure water (mass ratio 5/5) to obtain a solid that was purified by precipitation. This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained solid was dried under reduced pressure to obtain 11.0 g of a white polymer (c-2).

This polymer (c-2) had Mw of 5,500, Mn of 4,400, and Mw / Mn of 1.25. As a result of ¹ H-NMR analysis, the content ratios of structural units derived from styrene, methyl methacrylate and methacrylic acid were 80 mol%, 15 mol% and 5 mol%, respectively.

[Synthesis Example 1-14] (Synthesis of Polymer (c-3))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 40 g of anisole, 14.6 g (0.140 mol) of styrene, 6.00 g (0.060 mol) of methyl methacrylate, 4-cyano- [4-dodecyl (sulfanyl) Thio) carbonylsulfane] pentanoic acid 0.403 g (1 mmol) and azoisobutyronitrile 0.164 g (1 mmol) were added, and the mixture was heated and stirred at 80 ° C. for 8 hours. The obtained polymerization reaction liquid was added to 1,000 g of methanol / ultra pure water (mass ratio 5/5) to obtain a solid which was precipitated. This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained solid was dried under reduced pressure to obtain 11.5 g of a yellow polymer (c-3).

This polymer (c-3) had Mw of 8,400, Mn of 6,600, and Mw / Mn of 1.27. As a result of ¹ H-NMR analysis, the content ratios of structural units derived from styrene and methyl methacrylate were 70 mol% and 30 mol%, respectively.

[Synthesis Example 1-15] (Synthesis of Polymer (c-4))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 40 g of anisole, 14.6 g (0.140 mol) of styrene, 6.00 g (0.006 mol) of methyl methacrylate and 4-cyano-4-[(dodecylsulfanyl) 0.417 g (1.00 mmol) of methyl thiocarbonyl) sulfanyl] pentanoate was added, heated to 80 ° C., and stirred for 8 hours. The obtained polymerization reaction liquid was added to 1,000 g of methanol / ultra pure water (mass ratio 5/5) to obtain a solid which was precipitated. This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained yellow polymer had Mw of 8,600, Mn of 6,500, and Mw / Mn of 1.32.

Next, the obtained yellow solid was dissolved in dimethylformamide, 2.80 g (10 mmol) of 4,4′-azobis-4-cyanovaleric acid was added, heated to 80 ° C., and stirred for 3 hours. After the azo decomposition was completed, 1,000 g of methanol / ultra pure water (mass ratio 5/5) was added to obtain a precipitated solid. This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained solid was dried under reduced pressure to obtain 11.0 g of a yellow polymer (c-4).

This polymer (c-4) had an Mw of 8,400, an Mn of 6,200, and an Mw / Mn of 1.35. As a result of ¹ H-NMR analysis, the content ratios of structural units derived from styrene and methyl methacrylate were 70 mol% and 30 mol%, respectively.

[Synthesis Example 1-16] (Synthesis of Polymer (c-5))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 40 g of anisole, 14.6 g (0.140 mol) of styrene, 6.00 g (0.060 mol) of methyl methacrylate, 0.29 g of copper (II) bromide ( 2.00 mmol) and 0.46 g (2.0 mmol) of tris [(2-dimethylamino) ethyl] amine were added and heated to 100 ° C., and 0.53 (3.6 mmol) of ethyl 2-bromoisobutyrate was added with a syringe. In addition, the mixture was heated and stirred for 8 hours under a nitrogen flow. The obtained polymerization reaction liquid was filtered through Celite to remove the copper complex, and washing with 500 g of ultrapure water was repeated three times. After the organic layer was collected, it was concentrated, and a solid obtained by adding 50 g of THF to the resulting concentrate was added to 1,000 g of methanol / ultra pure water (mass ratio 5/5) and purified by precipitation. This solid was recovered with a Buchner funnel and washed with 50 g of methanol. The obtained solid was dried under reduced pressure to obtain 11.5 g of a white polymer (c-5).

This polymer (c-5) had Mw of 6,700, Mn of 5,800, and Mw / Mn of 1.16. As a result of ¹ H-NMR analysis, the structural units derived from styrene and methyl methacrylate were 70 mol% and 30 mol%, respectively.

<Preparation of composition>
[Preparation of Composition (I)]
[Preparation Example 1-1]
To 1.5 g of the synthesized [A] polymer (a-1), 69 g of propylene glycol monomethyl ether acetate and 29.5 g of ethyl lactate as the [S] solvent were added, stirred, and then 0.45 μm The mixture was filtered through a high-density polyethylene filter having pores to prepare composition (A-1).

[Preparation Examples 1-2 and 1-3]
[A] In the same manner as in Preparation Example 1-1 except that the same mass of (a-2) or (a-3) was used instead of the above (a-1) as the polymer, the composition ( A-2) and (A-3) were prepared.

[Preparation of Composition (II)]
[Preparation Example 1-4]
After 98.8 g of propylene glycol monomethyl ether acetate as a [S] solvent was added to 1.2 g of (b-1) as the synthesized [B] polymer and dissolved, a high pore having 0.45 μm pores was obtained. The mixture was filtered through a density polystyrene filter to prepare a composition (B-1).

[Preparation Examples 1-5 to 1-11]
[B] In the same manner as in Preparation Example 1-4 except that the same mass of (b-2) to (b-8) was used in place of (b-1) as a polymer, the composition ( B-2) to (B-8) were prepared.

[Preparation of Composition (III)]
[Preparation Example 1-12]
After 98.8 g of propylene glycol monomethyl ether acetate as the [S] solvent was added to 1.2 g of (c-1) as the synthesized [C] polymer and dissolved, a high pore having 0.45 μm pores was obtained. The mixture was filtered through a density polystyrene filter to prepare a composition (C-1).

[Preparation Examples 1-13 to 1-16]
[C] In the same manner as in Preparation Example 1-12 except that the same mass of (c-2) to (c-5) was used instead of the above (c-1) as the polymer, the composition ( C-2) to (C-5) were prepared.

[Preparation of Composition (IV)]
[Preparation Example 1-17]
The above synthesized [B] polymer (b-2) 0.6 g and [C] polymer (c-5) 0.6 g were added to [S] solvent propylene glycol monomethyl ether acetate 98.8 g. Was added and dissolved, followed by filtration with a high-density polystyrene filter having pores of 0.45 μm to prepare a composition (D-1).

[Preparation Examples 1-18 to 1-28]
Compositions (D-2) to (D-12) were prepared in the same manner as in Preparation Example 1-17, except that the respective polymers shown in Table 5 were used.

<Preparation of resist composition>
[Synthesis of polymer]
The monomer compounds used for the synthesis of the polymers (a1-1) and (a2-1) are shown below.

[Synthesis Example 1-17] (Synthesis of Polymer (a1-1))
12.9 g (50 mol%) of the compound (M-1) and 17.1 g (50 mol%) of the compound (M-2) were dissolved in 60 g of methyl ethyl ketone, and 2,2′-azobisisobutyronitrile was further dissolved. (AIBN) 1.77 g was added and dissolved to prepare a monomer solution. Next, a 200 mL three-necked flask charged with 30 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution was added over 3 hours using a dropping funnel. It was dripped. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water, cooled to 30 ° C. or lower, poured into 600 g of methanol, and the precipitated white powder was separated by filtration. The white powder separated by filtration was washed with 150 g of methanol twice in a slurry state, then filtered again and dried at 50 ° C. for 17 hours to obtain a white powder polymer (a1-1). (Yield 80%). Mw of the polymer (a1-1) was 6,900, and Mw / Mn was 1.35. As a result of ¹³ C-NMR analysis, the content ratios of structural units derived from (M-1) and (M-2) in the polymer (a1-1) were 49 mol% and 51 mol%, respectively. .

[Synthesis Example 1-18] (Synthesis of Polymer (a2-1))
10.4 g (30 mol%) of the compound (M-3) and 19.6 g (70 mol%) of the compound (M-4) are dissolved in 60 g of methyl ethyl ketone, and 2,2′-azobis (isobutyronitrile) is further dissolved. A monomer solution charged with 0.91 g (5 mol% based on the total amount of compounds) was prepared. Next, a 200 mL three-necked flask charged with 30 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution was added dropwise over 3 hours using a dropping funnel. did. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water, cooled to 30 ° C. or lower, poured into 600 g of methanol, and the precipitated white powder was separated by filtration. The white powder separated by filtration was washed twice with 150 g of methanol, and then filtered again and dried at 50 ° C. for 12 hours to obtain a white powder polymer (a2-1) ( Yield 68%). Mw of the polymer (a2-1) was 5,900, and Mw / Mn was 1.58. As a result of ¹³ C-NMR analysis, the content ratios of structural units derived from (M-3) and (M-4) in the polymer (a2-1) were 31 mol% and 69 mol%, respectively. .

[Preparation Example 1-29] (Preparation of resist composition (J-1))
100 parts by mass of the polymer (a1-1) synthesized above and 3 parts by mass of the polymer (a2-1),

triphenylsulfonium

1,1,2,2-tetrafluoro-6- ( 1-adamantane carbonyloxy) hexane-1-sulfonate 10.8 parts by weight, 4.3 parts by weight of triphenylsulfonium salicylate as an acid diffusion controller, and 2,185 parts by weight of propylene glycol monomethyl ether acetate as a solvent Then, 935 parts by mass of cyclohexanone and 30 parts by mass of γ-butyrolactone were mixed to prepare a resist composition (J-1).

<Formation of basic pattern>
[Formation of basic pattern (1)]
On the Bare-Si substrate, an underlayer film having an average thickness of 85 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. The obtained substrate was spin-coated with the composition (III) (compositions (C-1) to (C-5)) shown in Table 1 below at 1,500 rpm and baked at 220 ° C. for 60 seconds. The substrate after baking was rinsed with propylene glycol monomethyl ether acetate (PGMEA) for 4 seconds to remove unreacted substances and the like. Next, the resist composition (J-1) prepared above is applied to the substrate after removal of unreacted substances, etc. to form a resist film of 85 nm, exposed to ArF immersion exposure, developed using butyl acetate, A resist hole pattern having a size of 60 nm and a pitch of 150 nm was formed.

The obtained resist hole pattern was spin-coated with the composition (II) (compositions (B-1) to (B-8)) shown in Table 1 below at 1,500 rpm, and heated at 220 ° C. for 60 seconds. Baked. The substrate after firing was rinsed with propylene glycol monomethyl ether acetate (PGMEA) for 4 seconds to remove unreacted substances and the like, and basic patterns (P-1) to (P-12) were formed.

In the basic pattern (P-13), in the formation of the basic pattern (1), the composition (B-2) is used as the composition (III), and the composition (C-1) is used as the composition (II). It was formed by using.
The basic pattern (P-14) was formed by using the composition (B-2) as the composition (III) and the composition (II) in the formation of the basic pattern (1).
The basic pattern (P-15) was formed by using the composition (C-1) as the composition (III) and the composition (II) in the basic pattern formation (1).
The basic pattern (P-16) was formed without applying the composition (III) and the composition (II) in the formation of the basic pattern (1). ("-" In Table 1 indicates that compositions (II) and (III) were not applied.)

<Evaluation>
The static contact angle (unit: °) of water and the average thickness (unit: nm) of the coating film on the bottom and side surfaces of the recesses of the obtained basic patterns (P-1) to (P-16) are expressed as the contact angle. Measured by alternative evaluation using a coating film with the same surface condition as the basic pattern using a meter (“DSA10L2E” from KRUSS) and a high-speed spectroscopic ellipsometer (“M2000” from JA Woollam Japan) did. The evaluation results are shown in Table 1 below.

[Formation of basic pattern (2)]
On the Bare-Si substrate, an underlayer film having an average thickness of 85 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. The obtained substrate was spin-coated with the composition (III) (composition (C-1) or (C-2)) shown in Table 2 below at 1,500 rpm and baked at 220 ° C. for 60 seconds. The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted substances and the like. Next, a resist composition (“AIM5484JN” from JSR) is applied to the substrate after removal of unreacted substances, etc. to form a resist film of 85 nm, ArF immersion exposure, and 2.38 mass% tetrabutylammonium hydroxy The resist hole pattern was developed with an aqueous solution and baked at 180 ° C. to form a hole pattern with a hole size of 60 nm and a pitch of 150 nm.

The obtained resist hole pattern was spin-coated with a composition (II) (composition (B-4)) shown in Table 2 below at 1,500 rpm and baked at 220 ° C. for 60 seconds. The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted substances and the like, and basic patterns (P-17) and (P-18) were formed.

The static contact angle of water and the average thickness of the coating film on the bottom and side surfaces of the recesses of the basic patterns (P-17) and (P-18) formed above were measured according to the same method as described above. The evaluation results are shown in Table 2 below.

[Formation of basic pattern (3)]
On the Bare-Si substrate, an underlayer film having an average thickness of 85 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. The obtained substrate was spin-coated with the composition (III) (composition (C-1)) shown in Table 3 below at 1,500 rpm, and baked at 220 ° C. for 60 seconds. The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted substances and the like. Next, a resist composition (“AIM5484JN” from JSR) is applied to the substrate after removal of unreacted substances, etc. to form a resist film of 85 nm, ArF immersion exposure, and 2.38 mass% tetrabutylammonium hydroxy Development was performed using an aqueous solution of AlF, and the entire surface of ArF was exposed to form a resist hole pattern having a hole size of 60 nm and a pitch of 150 nm.

The obtained resist hole pattern was spin-coated with a composition (II) (composition (B-)) shown in Table 3 below at 1,500 rpm and baked at 220 ° C. for 60 seconds. The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted substances and the like, and basic patterns (P-19) and (P-20) were formed.

The static contact angle of water and the average thickness of the coating film on the bottom and side surfaces of the recesses of the formed basic patterns (P-19) and (P-20) were measured according to the same method as described above. The evaluation results are shown in Table 3 below.

[Formation of basic pattern (4)]
On the Bare-Si substrate, an underlayer film having an average thickness of 85 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. An 85 nm resist film is formed by applying the prepared resist composition (J-1) to the obtained substrate, exposed to ArF immersion, developed using butyl acetate, and has a hole size of 60 nm and a pitch of 150 nm. A resist hole pattern was formed.

The obtained resist hole pattern was spin-coated at 1,500 rpm with the composition (II) (compositions ((B-1) to (B-8)) shown in Table 4 below, The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted materials, etc. Next, the composition (III) shown in Table 4 below (composition (C-1)) To (C-5)) were spin-coated at 1,500 rpm and baked for 60 seconds at 220 ° C. The substrate after baking was rinsed for 4 seconds using PGMEA to remove unreacted substances, etc. Base patterns (P-21) to (P-32) were formed.

In the basic pattern (P-33), in the formation of the basic pattern (4), the composition (C-1) is used as the composition (II), and the composition (B-2) is used as the composition (III). It was formed by using.

The static contact angle of water and the average thickness of the coating film on the bottom and side surfaces of the recesses of the basic patterns (P-21) to (P-33) formed above were measured according to the same method as described above. The evaluation results are shown in Table 4 below.

[Formation of basic pattern (5)]
On the Bare-Si substrate, an underlayer film having an average thickness of 85 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. An 85 nm resist film is formed by applying the prepared resist composition (J-1) to the obtained substrate, exposed to ArF immersion, developed using butyl acetate, and has a hole size of 60 nm and a pitch of 150 nm. A resist hole pattern was formed.

The obtained resist hole pattern was spin-coated with the composition (IV) (compositions (D-1) to (D-12)) shown in Table 5 below at 1,500 rpm, and heated at 220 ° C. for 60 seconds. Baked. The substrate after firing was rinsed with PGMEA for 4 seconds to remove unreacted substances and the like, and basic patterns (P-34) to (P-45) were formed.

The basic pattern (P-46) was formed by using the composition (B-2) as the composition (IV) in the formation of the basic pattern (5).
The basic pattern (P-47) was formed by using the composition (C-1) as the composition (IV) in the basic pattern formation (5).
“-” In Table 5 indicates that the composition used does not contain both the [B] polymer and the [C] polymer.

The static contact angle of water and the average thickness of the coating film on the bottom and side surfaces of the recesses of the basic patterns (P-34) to (P-47) formed above were measured according to the same method as described above. The evaluation results are shown in Table 5 below.

<Formation of fine pattern>
[Examples 1-1 to 1-54 and Comparative Examples 1-1 to 1-5]
Using the basic patterns (P-1) to (P-47) formed above, a miniaturized contact hole pattern was formed by performing a filling step, a phase separation step and a removal step according to the following procedure.

(Filling process and phase separation process)
The prepared basic patterns (P-1) to (P-47) are spin-coated with the composition (I) prepared above (compositions (A-1) to (A-3)) at 1,500 rpm. It was coated by. The substrate was phase-separated by thermal annealing at 220 ° C. for 60 seconds under nitrogen.

(Removal process)
The substrate after the above phase separation step was irradiated with 172 nm radiation at an intensity of 300 mJ / cm ² , and then in a mixed solution of methyl isobutyl ketone (MIBK) / 2-propanol (IPA) (2/8 (mass ratio)). For 5 minutes to dissolve and remove the phase composed of the poly (methyl methacrylate) block in the polymers (A-1) to (A-3), thereby forming a miniaturized contact hole pattern.

<Evaluation>
About the formed miniaturized contact hole pattern, a high-magnification (300K) image is acquired using a scanning electron microscope (“CG4000” of Hitachi High-Technology Co., Ltd.), and a periodicity using a calculation tool (Hitachi High-Technology Co., Ltd.). By analyzing, the average diameter (unit: nm) and the placement error (x direction and y direction, unit: nm) of the contact hole pattern were evaluated.
The placement error (x direction, y direction) can be evaluated as good when it is 3.5 nm or less, and poor when it exceeds 3.5 nm.

Further, a photosensitive SOG composition (“DS492Y” manufactured by JSR) was spin-coated at 1,500 rpm on the substrate after the development, and then soft-baked at 80 ° C. for 30 seconds, and then 200 mJ / second with a KrF exposure machine. After irradiation with cm ² , a sol-gel curing reaction was performed at 80 ° C. for 120 seconds. Thus, after embedding the miniaturized contact hole pattern, the average thickness (unit: nm) of the bottom residue was measured by cross-sectional SEM observation using a length measurement SEM.

Table 6 below shows the evaluation results of the average diameter of the miniaturized contact hole pattern, the placement error, and the average thickness of the bottom residue.

As can be seen from the results in Table 6, according to the pattern forming method (A), even when the hole diameter is small, it is possible to form a hole pattern in which placement errors are suppressed and bottom residue is reduced.

<Pattern formation method (B)>
<[A ′] Polymer Synthesis>
[Synthesis Example 2-1] (Synthesis of Polymer (A-1))
A 500 mL flask reaction vessel was dried under reduced pressure, and then 120 g of tetrahydrofuran (THF) that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 3.10 mL (3.00 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into the THF, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. 16.6 mL (0.150 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the polymerization reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, a mixture of 0.63 mL (3.00 mmol) of 2-ethylhexyl glycidyl ether and 1 mL of methanol was injected as a terminal terminator to terminate the polymerization terminal. The polymerization reaction solution was warmed to room temperature, concentrated, and then replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% by mass oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the resulting solution was concentrated and then added dropwise to 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained polymer was dried at 60 ° C. under reduced pressure to obtain 14.8 g of a polymer represented by the following formula (A-1) as a white solid. This polymer (A-1) had Mw of 6,100, Mn of 5,700, and Mw / Mn of 1.07.

[Synthesis Example 2-2] (Synthesis of Polymer (A-2))
The 500 mL flask reaction vessel was dried under reduced pressure, and then 120 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 3.10 mL (3.00 mmol) of a 1-N cyclohexane solution of sec-BuLi was injected into this tetrahydrofuran, and thereafter, 16.6 mL of styrene subjected to adsorption filtration with silica gel to remove the polymerization inhibitor and distillation dehydration. (0.150 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the polymerization reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, a mixture of 0.27 mL (3.00 mmol) of methyl glycidyl ether and 1 mL of methanol was injected as an end terminator to terminate the polymerization end. The polymerization reaction solution was warmed to room temperature, concentrated, and then replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and then added dropwise to 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained polymer was dried at 60 ° C. under reduced pressure to obtain 14.6 g of a white polymer represented by the following formula (A-2). This polymer (A-2) had Mw of 6,100, Mn of 5,600, and Mw / Mn of 1.09.

[Synthesis Example 2-3] (Synthesis of Polymer (A-3))
After drying the 500 mL flask reaction vessel under reduced pressure, 110 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 3.43 mL (3.33 mmol) of a 1-N cyclohexane solution of sec-BuLi was injected into this tetrahydrofuran, and thereafter, 16.6 mL of styrene subjected to adsorption filtration with silica gel to remove the polymerization inhibitor and distillation dehydration. (0.150 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the polymerization reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, 0.27 mL (3.33 mmol) of 3-bromopropionitrile as a terminal terminator was injected to terminate the polymerization terminal. The polymerization reaction solution was warmed to room temperature, concentrated, and then replaced with MIBK. Thereafter, 1,000 g of a 2% by mass aqueous solution of oxalic acid was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and then added dropwise to 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained polymer was dried at 60 ° C. under reduced pressure to obtain 14.8 g of a white polymer represented by the following formula (A-3). This polymer (A-3) had Mw of 4,900, Mn of 5,600, and Mw / Mn of 1.14.

[Synthesis Example 2-4] (Synthesis of Polymer (A-4))
The 500 mL flask reaction vessel was dried under reduced pressure, and then 120 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 3.43 mL (3.33 mmol) of a 1-N cyclohexane solution of sec-BuLi was injected into this tetrahydrofuran, and thereafter, 16.6 mL of styrene subjected to adsorption filtration with silica gel to remove the polymerization inhibitor and distillation dehydration. (0.150 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the polymerization reaction solution did not exceed -60 ° C. After completion of dropping, the mixture was aged for 30 minutes. Thereafter, a mixture of 0.54 mL (6.66 mmol) of an excess amount of epibromohydrin and 1 mL of methanol was injected as a terminal terminator to terminate the polymerization terminal. The polymerization reaction solution was warmed to room temperature, concentrated, and then replaced with MIBK. Thereafter, 500 g of a 0.2% by mass aqueous solution of oxalic acid was poured and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 500 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and then added dropwise to 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. The obtained polymer was dried at 60 ° C. under reduced pressure to obtain 14.6 g of a white polymer represented by the following formula (A-4). This polymer (A-4) had Mw of 5,100, Mn of 5,500, and Mw / Mn of 1.08.

[Synthesis Example 2-5] (Synthesis of Polymer (A-5))
In a 200 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 10 g of toluene, 5.60 g (54 mmol) of styrene, 4.40 g (43 mmol) of methyl methacrylate, 0.039 g of azoisobutyronitrile (AIBN) (0. 24 mmol), 0.088 g (0.24 mmol) of 2-methyl-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid was added, and the mixture was heated and stirred at 60 ° C. for 4 hours under a nitrogen flow. The resulting polymerization reaction solution was purified by precipitation into 100 g of methanol to precipitate a polymer. This solid was recovered with a Buchner funnel and washed twice with 20 g of methanol to remove components derived from the initiator. By drying under reduced pressure, 2.5 g of a polymer represented by the following formula (A-5) as a white solid was obtained. This polymer (A-5) had Mn of 5,200 and Mw / Mn of 1.17. As a result of ¹ H-NMR analysis, the content ratios of structural units derived from styrene and structural units derived from methyl methacrylate were 49 mol% and 51 mol%, respectively.

[Synthesis Example 2-6] (Synthesis of Polymer (Aa))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of THF that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.30 mL (0.27 mmol) of a 1N cyclohexane solution of sec-BuLi was injected into this THF, and thereafter, 17.7 mL of styrene subjected to adsorption filtration with silica gel for removal of the polymerization inhibitor and distillation dehydration treatment. (0.154 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the polymerization reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.11 mL (0.00081 mol) of 1,1-diphenylethylene and 1.08 mL (0.0005 mol) of a 0.5N THF solution of lithium chloride were added, and the polymerization system was dark red It was confirmed that it became. Further, 10.0 mL (0.094 mol) of methyl methacrylate subjected to adsorption filtration with silica gel for removing the polymerization inhibitor and distilled and dehydrated was dropped into the polymerization reaction solution over 30 minutes, and the polymerization system was thin. After confirming that the color was yellow, the reaction was allowed to proceed for 120 minutes. Thereafter, 1 mL of methanol as a terminal terminator was injected to terminate the polymerization terminal. The polymerization reaction solution was warmed to room temperature, concentrated, and then replaced with MIBK. Thereafter, 1,000 g of a 2% by mass oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer, and a solid was recovered with a Buchner funnel. Next, 500 g of heptane was poured to remove the polystyrene homopolymer, the polymer was washed, and the polystyrene homopolymer was dissolved in heptane. This operation was repeated 4 times, and the solid was collected again with a Buchner funnel. The obtained polymer was dried at 60 ° C. under reduced pressure to obtain 24.1 g of a white polymer (Aa) represented by the following formula (Aa). This polymer (Aa) had Mw of 79,000, Mn of 77,000, and Mw / Mn of 1.03. As a result of ¹ H-NMR analysis, the polymer (Aa) was found to have a content of 60.0% by mass (60.0 mol) of structural units derived from styrene and structural units derived from methyl methacrylate. %) And 40.0 mass% (40.0 mol%) of diblock copolymer.

[Synthesis Example 2-7] (Synthesis of Polymer (Ab))
In a 100 mL three-necked flask equipped with a condenser, a dropping funnel and a thermometer, 5.23 g (3.44 mmol) of tetramethoxysilane, 1.12 g (0.57 mmol) of 3-mercaptopropyltrimethoxysilane, tert-butyl-2- ( 9.69 g (2.98 mmol) of (3-trimethoxysilylpropyl) thio) propionate and 9.20 g of propylene glycol monoethyl ether were added and stirred at 60 ° C., 4.33 g of 10% oxalic acid aqueous solution, ultrapure 0.43 g of water was dropped from a dropping funnel over 20 minutes, and the mixture was heated and stirred for 4 hours.
The resulting condensate solution was concentrated and then propylene glycol monoethyl ether was added to prepare a solid concentration of 30% by mass.

<Preparation of composition (V)>
Components other than the [A ′] polymer used for the preparation of the composition (V) are shown below.

[[S] solvent]
S1: Propylene glycol monomethyl ether acetate

[Preparation Example 2-1] (Preparation of composition (S-1))
[A ′] 100 parts by mass of (A-1) as a polymer and 9,900 parts by weight of (S1) as a [S] solvent are mixed, and the obtained mixed solution is filtered through a membrane filter having a pore size of 200 nm. A composition (S-1) was prepared.

[Preparation Examples 2-2 to 2-7] (Preparation of compositions (S-2) to (S-6) and (Sa))
Compositions (S-2) to (S-6) and (Sa) were prepared in the same manner as in Preparation Example 2-1, except that the components having the types and contents shown in Table 1 were used. .

<Formation of fine pattern>
[Examples 2-1 to 2-6 and Comparative Examples 2-1 and 2-2]
On the Bare-Si substrate, an underlayer film having an average thickness of 100 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. A positive resist composition (“AIM5484JN” manufactured by JSR) was applied to the obtained substrate to form a resist film having a thickness of 85 nm, ArF immersion exposure, organic solvent development, and a resist pattern were formed. Next, using this resist pattern as a mask, the SOG film was etched using a mixed gas of CF ₄ / O ₂ / Air. Next, using the obtained SOG film pattern as a mask, the lower layer film was etched with a N ₂ / O ₂ mixed gas to form a pre-pattern. A coating film is formed on the pre-pattern using the composition (V-1) shown in Table 8 below as the composition (V) and the temperature and time shown in Table 8 below. It baked on baking conditions and rinsed with PGMEA. “-” In Comparative Example 2-1 in Table 8 indicates that the composition (V) was not applied. Subsequently, a coating film was formed using (Sa) as the composition (VI) and baked at 220 ° C. for 20 minutes, and then the phase composed of the PMMA block in the polymer (Aa) with oxygen gas was formed. It removed and the refinement | miniaturization pattern was formed.

(Evaluation of substrate surface selectivity of composition (V))
An underlayer film having an average thickness of 100 nm was formed on a Bare-Si substrate using a composition for forming an underlayer film (“HM710” manufactured by JSR), and baked at 250 ° C. for 60 seconds and then 340 ° C. for 90 seconds. The surface layer of the lower layer film was etched with oxygen gas to prepare a substrate selectivity evaluation substrate (A). A coating film obtained by spin-coating (S-1) to (S-6) at 1500 rpm as a composition (V) on a substrate (A) and a Bare-Si substrate (hereinafter referred to as “substrate (B)”) After being formed, baked and rinsed with PGMEA, the water contact angle was measured. Bake conditions and contact angles are shown in Table 8 below. Note that a contact angle of 85 ° or more is regarded as a parent PS property surface, 74 ° to 78 ° as a neutral surface with respect to the PS block and PMMA block, and 70 ° or less as a parent PMMA surface. When the surface of the substrate (A) exhibits a PS property or a PMMA property and the surface of the substrate (B) exhibits neutrality, the substrate surface selectivity is considered good. As shown below, each of (S-1) to (S-6) was confirmed to have good substrate surface selectivity. The contact angle in the substrate (A) is considered to indicate the contact angle (θ1) of water on the side surface side of the concave portion of the basic pattern in the coating film after the heating step. The difference in contact angle between the substrate (A) and the substrate (B) in Comparative Example 2-1 was less than 5 °.

[Examples 2-7 and 2-8 and Comparative Examples 2-3 and 2-4]
On the Bare-Si substrate, an underlayer film having an average thickness of 100 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. A positive resist composition (“AIM5484JN” manufactured by JSR) was applied to the obtained substrate to form a resist film having a thickness of 85 nm, ArF immersion exposure, organic solvent development, and a resist pattern were formed. Next, using this resist pattern as a mask, the SOG film was etched using a mixed gas of CF ₄ / O ₂ / Air. Next, using the obtained SOG film pattern as a mask, the lower layer film was etched with a N ₂ / O ₂ mixed gas to form a pre-pattern. A coating film of (S-1) or (S-5) as a composition (V) was formed on the pre-pattern, baked under the baking conditions shown in Table 9 below, and rinsed with PGMEA. “−” In Comparative Example 2-4 of Table 9 below indicates that the composition (V) was not applied. Subsequently, a coating film of (Sa) was formed as a composition (VI) and baked at 220 ° C. for 20 minutes, and then the phase consisting of the PMMA block in the polymer (Aa) was removed with oxygen gas, A refined pattern was formed.

(Evaluation of coating film thickness uniformity of composition (VI))
The coating film thickness uniformity of the composition (VI) on the pre-pattern was evaluated by AFM. The evaluation results are shown in Table 9 below. When the selective modification process using the composition (V) was not applied, the film thickness locally increased due to the bimodal dispersion of the coating film thickness or the formation of the island pattern. On the other hand, when the selective modification process was applied, the formation of an island pattern was not observed, unimodal dispersion was exhibited, and good coating film thickness uniformity was confirmed.

[Example 2-9 and Comparative Example 2-5]
On the Bare-Si substrate, an underlayer film having an average thickness of 100 nm was formed using an underlayer film forming composition (“HM710” from JSR), and an SOG composition (“ISX302” from JSR) was formed on the underlayer film. ) Was used to form an SOG film having an average thickness of 30 nm. A positive resist composition (“EUVJ2121” from JSR) is applied to the obtained substrate to form a 50 nm resist film, exposed to EUV, and developed using an aqueous 2.38 mass% tetrabutylammonium hydroxide solution. Then, a resist pattern was formed. Next, using this resist pattern as a mask, the SOG film was etched using a mixed gas of CF ₄ / O ₂ / Air. Next, using the obtained SOG film pattern as a mask, the lower layer film was etched with a N ₂ / O ₂ mixed gas to form a pre-pattern. A coating film of (S-1) as a composition (V) was formed on the prepattern, baked under the baking conditions shown in Table 10 below, and rinsed with PGMEA. Subsequently, a coating film of (Sa) was formed as a composition (VI), baked at 220 ° C. for 20 minutes, and then the phase consisting of the PMMA block in the polymer (Aa) was removed with oxygen gas to obtain a fine Pattern was formed.

(Evaluation of pattern size uniformity (CDU))
CDU (nm) was evaluated by SEM for the fine hole pattern formed above. The evaluation results are shown in Table 10 below. Note that the smaller the value of CDU, the better. By applying the selective modification process using the composition (V), improvement in the uniformity of the pattern size indicated by CDU was confirmed.

As can be seen from the results in Table 10, according to the pattern formation method (B), by using the composition having excellent substrate surface selectivity, by forming a coating film having excellent film thickness uniformity, pattern size uniformity. Can be formed.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Resist pattern 3 Polymer layer 4 Packing layer 4a Block (α) phase 4b Block (β) phase

Claims

Forming a basic pattern on the surface side of the substrate directly or via another layer;
Filling the concave portion of the basic pattern with a first composition containing a first polymer having at least two blocks and a solvent;
A step of phase-separating the packed bed formed by the filling step;
Removing a part of the phase of the packed bed after the phase separation step;
Etching the substrate directly or indirectly using the miniaturized pattern formed by the removing step, and
The basic pattern forming process
Forming a resist pattern on the surface side of the substrate;
Forming a second polymer layer on at least a side surface of the resist pattern, and forming a third polymer layer different from the second polymer on at least the surface of the substrate or another layer.
The substrate and the other layers each have at least one of Si—H, Si—OH, Si═O, and Si—NR 2 on the upper surface, and each R is independently a hydrogen atom or a carbon number of 1 to 20 A monovalent organic group of
The resist pattern has at least one of -COOH and -OH on the side surface,
The second polymer has a first functional group bonded to at least one end of the main chain and forming a chemical bond with at least one of the -COOH and -OH;
The third polymer has a second functional group that is bonded to at least one end of the main chain and forms a chemical bond with at least one of Si—H, Si—OH, Si═O, and Si—NR 2. Pattern forming method.
The polymer layer forming step is
Applying a second composition containing the second polymer and a solvent;
The pattern forming method according to claim 1, further comprising: applying a third composition containing the third polymer and a solvent.
The pattern forming method according to claim 1, wherein the polymer layer forming step includes a step of applying a fourth composition containing the second polymer, the third polymer, and a solvent.
The pattern forming method according to claim 3, wherein the basic pattern forming step is performed in the order of the resist pattern forming step, the second composition coating step, and the third composition coating step.
The pattern forming method according to claim 3, wherein the basic pattern forming step is performed in the order of the third composition coating step, the resist pattern forming step, and the second composition coating step.
The pattern forming method according to claim 4, wherein the basic pattern forming step is performed by performing the resist pattern forming step, and the fourth composition coating step is performed after the step.
The resist pattern is formed by coating a resist composition containing a polymer having an acid-dissociable group and a radiation-sensitive acid generator, exposure, and development with an organic solvent developer. The pattern formation method of any one of Claims 1.
The resist pattern is formed by coating a resist composition containing a polymer having an acid dissociable group and a radiation-sensitive acid generator, exposure, development with an alkali developer and heating or exposure. Item 8. The pattern forming method according to any one of Items 7 above.
The pattern forming method according to claim 1, wherein the substrate or the other layer is made of SiO 2 or SiN.
The pattern forming method according to claim 1, wherein the other layer is a silicon-containing film.
The pattern forming method according to any one of claims 2 to 11, wherein the first functional group is a hydroxyl group, an epoxy group, or an oxetanyl group.
The pattern forming method according to any one of claims 2 to 11, wherein the second functional group is a carboxy group, a hydroxyl group, or a halogen atom.
The pattern forming method according to any one of claims 1 to 13, wherein the first polymer has two blocks, and the two blocks are a polystyrene block and a (meth) acrylate block.
The pattern formation method of any one of Claims 1-14 which forms a hole pattern.
A polymer having a functional group bonded to at least one end of the main chain and forming a chemical bond with at least one of -COOH and -OH;
Bonded to at least one end of the main chain, Si—H, Si—OH, Si═O and Si—NR 2 (R is each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms) A polymer having a functional group that forms a chemical bond with at least one of
A composition containing a solvent.
A step of laminating a basic pattern directly or via another layer on the surface side of the substrate;
Applying the fifth composition to the side and bottom surfaces of the concave portion of the basic pattern;
A step of heating the coating film formed by the coating step;
Filling the sixth composition into the concave portion of the basic pattern on which the coating film is laminated;
A step of phase-separating the packed bed formed by the filling step;
Removing at least a part of the phase of the packed bed after the phase separation step;
A step of etching the substrate one or more times using the miniaturized pattern formed by the removing step,
The basic pattern is mainly composed of a polymer having an aromatic ring content of 50% by mass or more,
The fifth composition contains a fourth polymer having a first structural unit and a solvent,
The sixth composition contains a fifth polymer having a first block composed of a second structural unit and a second block composed of a third structural unit having a higher polarity than the second structural unit, and a solvent,
The difference (| θ1-θ2 |) between the water contact angle θ1 on the side surface of the concave portion of the concave portion of the basic pattern and the water contact angle θ2 on the bottom surface in the coated film after the heating step is 5 ° or more. A pattern forming method.
The pattern forming method according to claim 17, wherein both the first structural unit and the second structural unit are derived from substituted or unsubstituted styrene.
In the above lamination process, the basic pattern is laminated directly on the surface side of the substrate,
The pattern forming method according to claim 17, wherein the substrate is made of silicon.
20. The pattern forming method according to claim 17, wherein the temperature or time is controlled in the heating step.
The pattern formation method according to claim 17, wherein the basic pattern is a hole pattern.