WO2013073505A1 - Self-organizing composition for pattern formation and pattern formation method - Google Patents

Abstract

The invention is a self-organizing composition for pattern formation comprising [A] a polymer with a heteroatom-containing group (α) on at least one end of the main chain, and [B] a polysiloxane. The heteroatom is preferably at least one kind selected from the group consisting of oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, tin atoms and silicon atoms. The group (α) is preferably represented by formula (1). The polymer [A] is preferably a styrene polymer. (1)

Description

Self-assembling composition for pattern formation and pattern forming method

The present invention relates to a self-assembling composition for pattern formation and a pattern forming method.

With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, pattern miniaturization in the lithography process is required. At present, it is possible to form a fine pattern with a line width of about 90 nm using, for example, an ArF excimer laser, but a finer pattern formation has been required.

In response to the above requirements, several pattern forming methods using so-called self-organized phase separation structures that spontaneously form ordered patterns have been proposed. For example, a method for forming an ultrafine pattern by self-assembly using a block copolymer obtained by copolymerizing a monomer compound having one property and a monomer compound having a different property is known. (See JP2008-149447, JP2002-519728, and JP2003-218383). According to this method, by annealing the composition containing the block copolymer, polymer structures having the same properties tend to gather together, so that a pattern can be formed in a self-aligning manner. Also known is a method of forming a fine pattern by self-organizing a composition containing a plurality of polymers having different properties (US Patent Application Publication No. 2009/0214823, Japanese Patent Application Laid-Open No. 2010-58403). reference).

However, it cannot be said that the conventional pattern formation method by self-organization is sufficient to make the pattern fine.

JP 2008-149447 A JP-T-2002-519728 JP 2003-218383 A US Patent Application Publication No. 2009/0214823 JP 2010-58403 A

The present invention has been made based on the circumstances as described above, and its object is to provide a self-assembling composition for pattern formation capable of forming a sufficiently fine pattern, and the self-organization for pattern formation. It is providing the pattern formation method using a chemical composition.

The invention made to solve the above problems is
[A] a polymer having a heteroatom-containing group (α) at at least one end of the main chain (hereinafter also referred to as “[A] polymer”), and [B] a pattern-forming self containing polysiloxane It is an organized composition.

The self-assembling composition for pattern formation contains [A] polymer and [B] polysiloxane, and [A] polymer has a group (α) containing a hetero atom at least at one end of the main chain. Since it becomes easy to carry out phase separation, a sufficiently fine pattern can be formed. Moreover, by having the group (α) containing a hetero atom, the pattern shape is stabilized, and variations in pattern size can be reduced. Here, the “terminal” in “at least one terminal of the main chain” refers to the carbon atom at the terminal end of the polymer main chain part formed when a polymer is synthesized by polymerizing monomers. .

The hetero atom is preferably at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a tin atom and a silicon atom. [A] When the polymer group (α) contains any of these heteroatoms, phase separation is more likely to occur.

The group (α) is preferably represented by the following formula (1).

(In Formula (1), R ¹ is a single bond or a divalent organic group having 1 to 30 carbon atoms. R ² is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms.)

In the self-assembling composition for pattern formation, the [A] polymer has a group (α) represented by the above formula (1) at least at one end of the main chain, thereby further facilitating phase separation. Therefore, a sufficiently fine and good pattern can be formed.

[A] The polymer is preferably a styrene polymer. [A] When the polymer is a styrenic polymer, phase separation is further facilitated, and thus the self-assembling composition for pattern formation can form a finer and better pattern.

[B] The polysiloxane is preferably a hydrolysis-condensation product of a hydrolyzable silane compound containing a compound represented by the following formula (2).

(In the formula (2), R ³ is an alkyl group having 1 to 8 carbon atoms or an organic group having 6 to 30 carbon atoms including an aromatic ring, provided that a part or all of the hydrogen atoms of the alkyl group are included. R ⁴ represents a chlorine atom or a monovalent group represented by —OR ^5. R ⁵ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms. Or an aryl group having 6 to 15 carbon atoms, provided that a part or all of the hydrogen atoms of the alkyl group, acyl group and aryl group may be substituted. Provided that when a is 2 or more, the plurality of R ³ may be the same or different, and when a is 2 or less, the plurality of R ⁴ may be the same or different. )

The self-assembling composition for pattern formation can form a finer pattern because [B] polysiloxane has the above specific structure, so that phase separation is more likely to occur.

In the self-assembling composition for pattern formation, the content of [B] polysiloxane with respect to 100 parts by mass of [A] polymer is preferably 20 parts by mass or more and 200 parts by mass. The self-assembling composition for pattern formation can form a fine and complicated desired pattern by containing the [A] polymer and the [B] polysiloxane in the specific ratio.

The pattern forming method of the present invention comprises:
(1) forming a self-assembled film having a phase separation structure on a substrate using the self-assembled composition for pattern formation of the present invention; and (2) removing a part of the phase of the self-assembled film. The process of carrying out is included.

In the pattern forming method of the present invention, since a self-assembled film is formed using the pattern-forming self-assembled composition, a sufficiently fine pattern can be formed.

The pattern forming method of the present invention comprises:
Before step (1) above,
(0-1) further comprising a step of forming a lower layer film on the substrate, and (0-2) a step of forming a pre-pattern on the lower layer film,
In the step (1), a method of forming a self-assembled film in a region on the lower layer film delimited by the pre-pattern is preferable.

When the pattern forming method of the present invention further includes a step of forming an underlayer film and a pre-pattern, the phase separation of the self-assembling composition for pattern formation is more precisely controlled, and the resulting pattern is finer can do.

The pattern obtained by the pattern forming method of the present invention is preferably a line and space pattern or a hole pattern. According to the pattern forming method, a finer desired line and space pattern or hole pattern can be formed.

The present invention can provide a self-assembling composition for forming a pattern capable of forming a sufficiently fine pattern and a pattern forming method using the same. Therefore, the self-assembling composition for pattern formation and the pattern forming method of the present invention are suitably used for lithography processes in the manufacture of various electronic devices such as semiconductor devices and liquid crystal devices that require further miniaturization.

In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a lower layer film | membrane on a board | substrate. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a pre pattern on a lower layer film. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after apply | coating the self-organizing composition for pattern formation to the area | region on the lower layer film | membrane divided by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a self-organization film | membrane in the area | region on the lower layer film pinched | interposed by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after removing the one part phase and pre pattern of a self-organization film | membrane.

Hereinafter, embodiments of the self-assembling composition for pattern formation and the pattern forming method of the present invention will be described in detail.

<Self-assembled composition for pattern formation>
Self-organized (Directed Self Assembly) refers to a phenomenon of spontaneously constructing an organization or structure, not only due to control from an external factor. In the present invention, a film having a phase separation structure by self-organization (self-assembled film) is formed by applying a self-assembled composition for pattern formation onto a substrate, and a part of this self-assembled film By removing this phase, a pattern can be formed.

The self-assembling composition for pattern formation of the present invention comprises: [A] a polymer having a hetero atom-containing group (α) at at least one end of the main chain, and [B] a self-pattern forming composition containing polysiloxane. It is an organized composition. The self-assembling composition for pattern formation contains a [A] polymer and [B] polysiloxane, each having a terminal structure of at least one main chain having the above-mentioned specific structure. In comparison, phase separation is more likely to occur, and a pattern having a sufficiently fine microdomain structure can be formed. The self-assembling composition for pattern formation contains, in addition to the [A] polymer and [B] polysiloxane, optional components such as other polymers, solvents, and surfactants, as long as the effects of the present invention are not impaired. You may do it.
Hereinafter, each component will be described in detail.

[[A] polymer]
[A] The polymer is a polymer having a group (α) containing a hetero atom at at least one end of the main chain (except for [B] polysiloxane). [A] The polymer is not particularly limited as long as it is a polymer having a group (α) at at least one end of the main chain, but a styrene polymer obtained by polymerizing a styrene compound, (meth) acrylate Acrylic polymers obtained by polymerizing compounds and copolymers thereof are preferred. Particularly preferred is a styrene polymer. In this specification, the notation “(meth) acrylate” represents both methacrylate and acrylate.

[A] The polymer is polymerized, for example, by treating the polymerization terminal with an appropriate terminal treating agent and introducing the group (α) or using a polymerization initiator containing the group (α). Can be synthesized.
[A] Since the polymer has a structure having the group (α) at least at one end of the main chain, phase separation is more likely to occur. Therefore, the self-assembling composition for pattern formation has been conventionally used. Compared with the composition of, a pattern having a finer and better microdomain structure can be formed.

Although it does not specifically limit as a hetero atom in group ((alpha)) containing the said hetero atom, It is at least 1 sort (s) selected from the group which consists of an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a tin atom, and a silicon atom. Are preferred, oxygen atoms, nitrogen atoms and sulfur atoms are more preferred, oxygen atoms and nitrogen atoms are more preferred, and oxygen atoms are particularly preferred.

The group (α) is preferably a group represented by the above formula (1).

In the above formula (1), R ¹ is a single bond or a divalent organic group having 1 to 30 carbon atoms. R ² is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms.

Examples of the divalent organic group having 1 to 30 carbon atoms represented by R ¹ include, for example, an aliphatic chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and carbon. Examples thereof include aromatic hydrocarbon groups of several 6 to 30 and groups having a hetero atom such as an oxygen atom or a nitrogen atom between carbon-carbons of these hydrocarbon groups.

Examples of the aliphatic chain hydrocarbon group having 1 to 30 carbon atoms include a methylene group, an ethanediyl group, an n-propanediyl group, an i-propanediyl group, an n-butanediyl group, an i-butanediyl group, and an n-pentanediyl group. I-pentanediyl group, n-hexanediyl group, i-hexanediyl group and the like. Among these, a methylene group and an ethanediyl group are preferable, and a methylene group is more preferable from the viewpoint that the pattern-forming self-assembled composition is more likely to cause phase separation.

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, a cyclooctanediyl group, a norbornanediyl group, and an adamantanediyl group. Can be mentioned.

Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include a phenylene group, a naphthalenylene group, and an anthracenylene group.

Examples of the group containing a group having a hetero atom such as an oxygen atom or a nitrogen atom between carbon-carbon of these hydrocarbon groups include, for example, —O—, —CO— between the carbon-carbon of the hydrocarbon group. , A group containing a linking group having at least one hetero atom such as —COO—, —OCO—, —NO—, —NH— and the like.

R ¹ is preferably a single bond or an aliphatic chain hydrocarbon group having 1 to 30 carbon atoms, more preferably a methylene group, an ethanediyl group or a propanediyl group, and even more preferably an ethanediyl group or a propanediyl group.

Examples of the monovalent organic group having 1 to 30 carbon atoms represented by R ² include an aliphatic chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and carbon. Examples thereof include aromatic hydrocarbon groups of several 6 to 30 and groups having a hetero atom such as an oxygen atom or a nitrogen atom between carbon-carbons of these hydrocarbon groups.

Examples of the aliphatic chain hydrocarbon group having 1 to 30 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, n-pentyl group, i -Pentyl group, n-hexyl group, i-hexyl group and the like.

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a norbornyl group, and an adamantyl group.

Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include a phenyl group, a naphthalenyl group, and an anthracenyl group.

Examples of the group containing a group having a hetero atom such as an oxygen atom or a nitrogen atom between carbon-carbon of these hydrocarbon groups include -O-, -CO-, And groups containing a linking group having at least one heteroatom such as —COO—, —OCO—, —NO—, —NH— and the like.

Examples of R ² include a hydrogen atom, an aliphatic chain hydrocarbon group having 1 to 30 carbon atoms, and a group having —O— between carbon and carbon of the aliphatic chain hydrocarbon group having 1 to 30 carbon atoms. A group having —O— between carbon and carbon of a hydrogen atom, an aliphatic chain hydrocarbon group having 1 to 3 carbon atoms, and an aliphatic chain hydrocarbon group having 1 to 10 carbon atoms is more preferable.

Examples of the group (α) include a structure represented by the following formula.

In the above formula, R is a hydrogen atom or a monovalent organic group. Q is a divalent organic group. * In the [A] polymer, the site | part couple | bonded with the carbon atom of the principal chain terminal of a polymer is shown.

Of these, the groups represented by (1-1) to (1-7) which are groups represented by the above formula (1) are preferable, and (1-2), (1-3) and (1- The group represented by 4) is more preferable.

[A] Examples of the polymer include a polymer obtained by polymerizing a compound such as a styrene compound or a (meth) acrylate compound. Examples of the styrene compounds include styrene, 2-methylstyrene, 4-methylstyrene, ethylstyrene, 4-methoxystyrene, 4-phenylstyrene, 2,4-dimethylstyrene, 4-n-octylstyrene, 4-n. -Decylstyrene, 4-n-dodecylstyrene, 4-t-butoxystyrene and the like. Of these, styrene, 2-methylstyrene, 4-methylstyrene, 4-methoxystyrene and 4-t-butoxystyrene are preferable, and styrene is more preferable. Examples of the (meth) acrylate compound include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and butyl (meth) acrylate; phenyl (meth) acrylate, benzyl Aryl (meth) acrylates such as (meth) acrylate, naphthyl (meth) acrylate, xylyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclooctyl (meth) acrylate, adamantyl (meth) acrylate, norbornyl Alicyclic (meth) acrylates such as (meth) acrylates are listed. Of these, phenyl (meth) acrylate, benzyl (meth) acrylate and butyl (meth) acrylate are preferred, and phenyl methacrylate, benzyl methacrylate and butyl methacrylate are more preferred.

[A] The polymer may be a homopolymer obtained by polymerizing one of the above compounds, or may be a copolymer obtained by polymerizing two or more compounds. Examples of such a copolymer include a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, and a styrene-acrylonitrile-butadiene copolymer. [A] The polymer is preferably a homopolymer, and more preferably a styrene homopolymer.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized by living anionic polymerization, living radical polymerization or the like, and among these, living anionic polymerization in which any terminal structure can be easily introduced is preferable. For example, monomers such as styrene and (meth) acrylate are polymerized in the presence of an arbitrary polymerization initiator, and the polymerization terminal is treated with an arbitrary terminal treatment agent, and the above group such as the group represented by the above formula (1) It can be synthesized by introducing the group (α).

As the above polymerization method, for example, it can be synthesized by a method such as a method of dropping a solution containing a monomer such as styrene into a reaction solvent containing a polymerization initiator to cause a polymerization reaction.

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;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, 2-butanone, 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 is usually −150 ° C. to 50 ° C., preferably −80 ° C. to 40 ° C. The reaction time is usually 5 minutes to 24 hours, preferably 20 minutes to 12 hours.

Examples of the initiator used for the polymerization include alkyllithium, alkylmagnesium halide, sodium naphthalene, alkylated lanthanoid compounds, and the like. When polymerizing using styrene or methyl methacrylate as a monomer, It is preferable to use an alkyl lithium compound.

Examples of the terminal treatment method include a method as shown in the following scheme when the [A] polymer is a polystyrene having a group (α) at the end of the main chain. That is, by adding a terminal treating agent such as 1,2-butylene oxide to the obtained polystyrene to modify the terminal and performing a metal removal treatment with an acid or the like, a group represented by the above formula (1) ( [A] polymer having α) at the terminal is obtained.

In the above scheme, m is an integer of 10 to 5,000.

Examples of the end treatment agent include epoxy compounds such as 1,2-butylene oxide, butyl glycidyl ether, propylene oxide, ethylene oxide, 2-ethylhexyl glycidyl ether, and epoxyamine;
Isocyanate compound, thioisocyanate compound, imidazolidinone, imidazole, aminoketone, pyrrolidone, diethylaminobenzophenone, nitrile compound, aziridine, formamide, epoxyamine, benzylamine, oxime compound, azine, pyrazone, imine, azocarboxylic acid ester, aminostyrene, vinyl Nitrogen-containing compounds such as pyridine, aminoacrylate, aminodiphenylethylene, and imide compounds;
Silane compounds such as alkoxysilane, aminosilane, ketinominosilane, isocyanate silane, siloxane, glycidylsilane, mercaptosilane, vinyl silane, epoxy silane, pyridylsilane, piperazylsilane, pyrrolidone silane, cyanosilane, and isocyanate silane;
Examples thereof include tin halide, silicon halide, carbon dioxide and the like. Of these, epoxy compounds are preferable, and 1,2-butylene oxide, butyl glycidyl ether, propylene oxide, and 2-ethylhexyl glycidyl ether are more preferable.

[A] The polymer can also be synthesized by polymerization using an initiator containing the group (α). Examples of such polymerization include radical polymerization using a radical polymerization initiator containing a group (α).

Examples of radical polymerization initiators containing the above group (α) include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis. (2-cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), dimethyl 2,2'-azobis Isobutyrate, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2, 2′-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide], 2,2′-azobis (N-butyl-2- Tyrpropionamide), 2,2′-azobis (N-cyclohexyl-2-methylpropionamide), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and other azo radicals Polymerization initiators: peroxide radical polymerization initiators such as bis (3-carboxypropionyl) peroxide, bis (4-tert-butylcyclohexyl) purge carbonate, didodecanoyl peroxide, and pivaloyl tert-butyl peroxide. Among these, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] and 2,2′-azobis [2- (2-imidazolin-2-yl) propane] are preferable. . In addition, you may use a radical initiator individually or in combination of 2 or more types.

Examples of the polymerization solvent used in the radical polymerization include those exemplified as the polymerization solvent used in the living anion polymerization and the like.

The reaction temperature in the radical polymerization may be appropriately determined depending on the initiator type. Usually, it is 30 ° C to 150 ° C, preferably 40 ° C to 150 ° C, and more preferably 50 ° C to 140 ° C. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, more preferably 1 hour to 5 hours. Further, the total reaction time including the dropping time varies depending on the conditions as in the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, and more preferably 1 to 10 hours.

The [A] polymer having a group (α) at the end of the main chain obtained by the above polymerization is 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.

[A] The weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC) is preferably 1,000 to 200,000, more preferably 3,000 to 120,000, and more preferably 3,500 to 100. Is more preferred. [A] By setting the Mw of the polysiloxane within the above specific range, the self-assembling composition for pattern formation can form a pattern having a finer microdomain structure.

[A] The ratio (Mw / Mn) of Mw and number average molecular weight (Mn) of the polymer is usually 1 to 5, preferably 1 to 3, more preferably 1 to 2, and more preferably 1 to 1.5. Is more preferable, and 1 to 1.2 is particularly preferable. By making Mw / Mn into such a specific range, the self-assembling composition for pattern formation can form a pattern having a finer and better microdomain structure.

Mw and Mn are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, or more from Tosoh), flow rate 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1.0 mass%, sample injection It was measured by gel permeation chromatography (GPC) using a monodisperse polystyrene as a standard, using a differential refractometer as a detector under analysis conditions of an amount of 100 μL and a column temperature of 40 ° C.

<[B] Polysiloxane>
[B] The polysiloxane contained in the self-assembling composition for pattern formation is not particularly limited as long as it is a hydrolyzed condensate of a hydrolyzable silane compound, but includes a compound represented by the above formula (2). It is preferably a hydrolysis condensate of a hydrolyzable silane compound.

In the above formula (2), R ³ is an alkyl group having 1 to 8 carbon atoms or an organic group having 6 to 30 carbon atoms including an aromatic ring. However, one part or all part of the hydrogen atom which this alkyl group has may be substituted. R ⁴ is a monovalent group represented by a chlorine atom or —OR ⁵ . R ⁵ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an acyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 15 carbon atoms. However, some or all of the hydrogen atoms of the alkyl group, acyl group and aryl group may be substituted. a is an integer of 1 to 3. However, when a is 2 or more, the plurality of R ³ may be the same or different. When a is 2 or less, the plurality of R ⁴ may be the same or different.

Examples of the alkyl group having 1 to 8 carbon atoms represented by R ³ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, and an n-hexyl group. Is mentioned.

Preferred examples of the organic group having 6 to 30 carbon atoms including the aromatic ring represented by R ³ include a group represented by the following formula (2-a).

In the above formula (2-a), R ⁶ is a single bond or a chain hydrocarbon group having 1 to 10 carbon atoms. R ⁷ is a fluorine atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. b is 0 or 1. c is an integer of 0 to 5. However, when c is 2 or more, the plurality of R ⁷ may be the same or different. * Shows the site | part couple | bonded with Si.

Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by R ⁶ include a methylene group, an ethanediyl group, a propanediyl group, a butanediyl group, and a pentanediyl group.
Among these, a methylene group, an ethanediyl group and a propanediyl group are preferable, a methylene group and an ethanediyl group are more preferable, and an ethanediyl group is more preferable.

R ⁶ is preferably a single bond, a methylene group or an ethanediyl group, more preferably a single bond or an ethanediyl group.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁷ include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

Examples of the alkoxy group having 1 to 6 carbon atoms represented by R ⁷ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group. Of these, a butoxy group is preferred.

R ⁷ is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably a butoxy group.

B is preferably 0, and c is preferably 0 to 2, more preferably 0 and 1.

Examples of the substituent that the alkyl group represented by R ³ may have include a fluorine atom, a hydroxyl group, and an acyl group.

R ³ is preferably an organic group having 6 to 30 carbon atoms including an aromatic ring from the viewpoint of easy phase separation of the self-assembling composition for pattern formation, and is represented by the above formula (2-a). Are more preferred.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁵ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a t-butyl group.

Examples of the acyl group having 1 to 6 carbon atoms represented by R ⁵ include an acetyl group, a propionyl group, and a butyryl group.

Examples of the aryl group having 6 to 15 carbon atoms represented by R ⁵ include a phenyl group and a naphthalenyl group.

Examples of the substituent that the alkyl group, acyl group, and aryl group represented by R ⁵ may have include a chain hydrocarbon group having 1 to 10 carbon atoms, a fluorine atom, and a hydroxyl group.

R ⁴ is preferably a monovalent group represented by —OR ⁵ , more preferably R ⁵ is an alkoxy group having 1 to 6 carbon atoms, and an ethoxy group is more preferable. .

A in the above formula (2) is an integer of 1 to 3. When a is 1, it is a trifunctional silane, when a is 2, it is a bifunctional silane, and when a is 3, it is a monofunctional silane. Among these, 1 and 2 are preferable as a, and 1 is more preferable.

Examples of the hydrolyzable silane compound represented by the above formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltri i-propoxysilane, methyltrin-butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, Ethyltri i-propoxysilane, ethyltri n-butoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyl Triethoxysilane, decyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypro Pyrtrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 4-t-butoxyphenethyltriethoxysilane, 1- (t-butoxyphenyl) ethyltriethoxysilane, t-butoxyphenyltriethoxysilane, p-hydroxyphenyl Trimethoxysilane, 1- (p-hydroxyphenyl) ethyltrimethoxysilane, 2- (p-hydroxyphenyl) ethyltrimethoxysilane, 4-hydroxy-5- (p-hydroxyphenylcarbonyloxy) pentyltrimethoxysilane, tri Fluoromethyltrimethoxysilane, trifluoromethyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-functional silanes such as 3-mercaptopropyltrimethoxysilane;
Bifunctional silanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiacetoxysilane, di-n-butyldimethoxysilane, and diphenyldimethoxysilane; monofunctional silanes such as trimethylmethoxysilane and tri-n-butylethoxysilane .

Among these, [B] polysiloxane is hydrolyzed having an aromatic ring from the viewpoint that the compatibility with [A] polymer and the ease of phase separation can be appropriately balanced. Silane compounds are preferable, and phenyltrimethoxysilane, phenyltriethoxysilane, 4-t-butoxyphenethyltriethoxysilane, 1- (t-butoxyphenyl) ethyltriethoxysilane, and t-butoxyphenyltriethoxysilane are more preferable. [B] The polysiloxane may be a hydrolysis condensate of one of these hydrolyzable silane compounds, or may be a hydrolysis condensate of two or more compounds. .

<[B] Polysiloxane Synthesis Method>
[B] As a method for synthesizing polysiloxane, for example, at least a part of the hydrolyzable silane compound represented by the above formula (2) is hydrolyzed to convert the hydrolyzable group (—R ⁴ ) into a silanol group. And as long as it causes a condensation reaction, it is not particularly limited, but can be carried out as follows as an example.

The water used for the hydrolytic condensation of the hydrolyzable silane compound represented by the above formula (2) is preferably water purified by a method such as reverse osmosis membrane treatment, ion exchange treatment or distillation. By using such purified water, side reactions can be suppressed and the reactivity of hydrolysis can be improved. The amount of water used is preferably from 0.1 to 3 mol, more preferably from 0.3 to 1 mol, based on 1 mol of the total amount of hydrolyzable groups of the hydrolyzable silane compound represented by the above formula (2). The amount is 2 mol, more preferably 0.5 to 1.5 mol. By using such an amount of water, the hydrolysis / condensation reaction rate can be optimized.

Although it does not specifically limit as a solvent which can be used for the hydrolysis condensation of the hydrolysable silane compound represented by the said Formula (2), Usually, the self-organization composition for pattern formation mentioned later is The thing similar to what was illustrated as a solvent to contain can be used. Of these solvents, ethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate, propionic acid esters are preferred, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, methyl 3-methoxypropionate, or diacetone alcohol is more preferable.

The hydrolysis / condensation reaction of the hydrolyzable silane compound represented by the above formula (2) is preferably an acid catalyst (for example, hydrochloric acid, sulfuric acid, nitric acid, formic acid, oxalic acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid). , Phosphoric acid, acidic ion exchange resins, various Lewis acids), basic catalysts (eg, nitrogen-containing compounds such as ammonia, primary amines, secondary amines, tertiary amines, pyridine; basic ion exchange resins; water) Conducted in the presence of a catalyst such as hydroxide such as sodium oxide; carbonate such as potassium carbonate; carboxylate such as sodium acetate; various Lewis bases] or alkoxide (eg, zirconium alkoxide, titanium alkoxide, aluminum alkoxide). Is called. For example, tri-i-propoxyaluminum can be used as the aluminum alkoxide. The amount of the catalyst used is preferably 0.2 mol or less, more preferably 0.00001 to 0.1 mol per mol of the hydrolyzable silane compound monomer from the viewpoint of promoting the hydrolysis condensation reaction. Is a mole.

The reaction temperature and reaction time in the hydrolytic condensation of the hydrolyzable silane compound represented by the above formula (2) are appropriately set. For example, the following conditions can be adopted. The reaction temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 150 ° C. The reaction time is preferably 30 minutes to 24 hours, more preferably 1 hour to 12 hours. By setting such reaction temperature and reaction time, the hydrolysis condensation reaction can be performed most efficiently. In this hydrolysis condensation, the reaction may be carried out in one step by adding the hydrolyzable silane compound, water and catalyst to the reaction system at one time, or the hydrolyzable silane compound, water and catalyst may be added in several steps. The hydrolysis condensation reaction may be carried out in multiple stages by adding it to the reaction system in batches. After the hydrolysis condensation reaction, water and the produced alcohol can be removed from the reaction system by adding a dehydrating agent and then subjecting it to evaporation. The dehydrating agent used at this stage is generally consumed or adsorbed by excess water, so that the dehydrating ability is completely consumed or removed by evaporation.

[B] The molecular weight of the polysiloxane can be measured as a weight average molecular weight (Mw) in terms of polystyrene using GPC (gel permeation chromatography) using tetrahydrofuran as a mobile phase. The Mw of the hydrolyzed condensate is usually preferably a value within the range of 500 to 10,000, more preferably a value within the range of 1,000 to 5,000. By setting the value of Mw of the hydrolysis-condensation product to 500 or more, the film formability of the self-assembled film can be improved. On the other hand, when the Mw value of the hydrolysis-condensation product is 10,000 or less, phase separation of the self-assembling composition for pattern formation is more likely to occur.

[Other polymers]
The self-assembling composition for pattern formation may further contain other polymers in addition to the [A] polymer and the [B] polysiloxane.

Examples of other polymers include (meth) acrylic polymers, polyvinyl acetal polymers, polyurethane polymers, polyurea polymers, polyimide polymers, polyamide polymers, epoxy polymers, novolac-type phenol polymers, polyester polymers, and the like. Can be mentioned. The polymer may be a homopolymer synthesized from one type of monomer compound or a copolymer synthesized from a plurality of types of monomer compounds.

The content ratio of the [A] polymer and [B] polysiloxane in the self-assembling composition for pattern formation is 20 parts by mass or more of [B] polysiloxane with respect to 100 parts by mass of the [A] polymer. The content is preferably 200 parts by mass or less, more preferably 50 parts by mass or more and 150 parts by mass or less, and further preferably 75 parts by mass or more and 125 parts by mass or less. By setting the content ratio of the [A] polymer and the [B] polysiloxane in the self-assembling composition for pattern formation within the specific range, a more complicated fine pattern can be formed.

[solvent]
The self-assembling composition for pattern formation usually contains a solvent. Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and mixed solvents thereof.

Examples of alcohol solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-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-heptadec Monoalcohol solvents such as 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, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl 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, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of the ether solvent include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether and the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n- And ketone solvents such as hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, etc. .

Examples of amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, Examples thereof include N-methylpropionamide and N-methylpyrrolidone.

Examples of ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec sec -Butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, acetoacetic acid Methyl, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate Mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate , Methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, methyl 3-methoxypropionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-lactate Examples include butyl, n-amyl lactate, diethyl malonate, dimethyl phthalate, and diethyl phthalate.

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

Of these, propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone and γ-butyrolactone are preferred, and propylene glycol monomethyl ether acetate (PGMEA) is more preferred. These solvents may be used alone or in combination of two or more.

[Surfactant]
The pattern-forming self-assembled composition may further contain a surfactant. When the self-assembling composition for pattern formation contains a surfactant, applicability to a substrate or the like can be improved.

<Method for Preparing Self-Assembled Composition for Pattern Formation>
The self-assembling composition for pattern formation can be prepared, for example, by mixing [A] polymer, [B] polysiloxane, surfactant and the like in a predetermined ratio in the above solvent. The self-assembling composition for pattern formation can be prepared and used in a state dissolved or dispersed in a suitable solvent.

<Pattern formation method>
The pattern forming method of the present invention comprises:
(1) forming a self-assembled film having a phase separation structure on a substrate using the self-assembled composition for pattern formation of the present invention; and (2) removing a part of the phase of the self-assembled film. It is a pattern formation method including the process to do.

Further, before the step (1), the method further comprises (0-1) a step of forming a lower layer film on the substrate, and (0-2) a step of forming a pre-pattern on the lower layer film. ) Step, it is preferable to form a self-assembled film in a region on the lower layer film delimited by the pre-pattern. If necessary, in the step (2), the pre-pattern may be removed in addition to a part of the phase of the self-assembled film.

Furthermore, it is preferable to further include (3) a step of etching the substrate using the formed pattern as a mask after the step (2). Hereinafter, each process is explained in full detail. Each step will be described with reference to FIGS.

[Step (0-1)]
This step is a step of forming a lower layer film on the substrate using the lower layer film forming composition. Thereby, as shown in FIG. 1, a substrate with a lower layer film in which the lower layer film 102 is formed on the substrate 101 can be obtained, and the self-assembled film is formed on the lower layer film 102. The phase separation structure (microdomain structure) of the self-assembled film is in addition to the interaction between the polymer such as [A] polymer and [B] polysiloxane contained in the self-assembled composition for pattern formation. Since it also changes due to the interaction with the lower layer film 102, the structure control is possible by having the lower layer film 102, and a desired pattern can be obtained. Further, when the self-assembled film is a thin film, the transfer process can be improved by having the lower layer film 102.

As the substrate 101, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used.

Moreover, as the composition for forming the lower layer film, for example, materials commercially available under trade names such as ARC66 (manufactured by Brewer Science), NFC HM8005 (manufactured by JSR), NFC CT08 (manufactured by JSR), and the like can be used.

The formation method of the lower layer film 102 is not particularly limited. For example, a coating film formed by applying a known method such as a spin coating method on the substrate 101 is cured by exposure and / or heating. can do. Examples of radiation used for this exposure include visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ-rays, molecular beams, and ion beams.
The temperature at which the coating film is heated is not particularly limited, but is preferably 90 ° C to 550 ° C, more preferably 90 ° C to 450 ° C, and further preferably 90 ° C to 300 ° C. The thickness of the lower layer film 102 is not particularly limited, but is preferably 50 nm to 20,000 nm, and more preferably 70 nm to 1,000 nm. The lower layer film 102 preferably includes an SOC (Spin on carbon) film.

[Step (0-2)]
In this step, as shown in FIG. 2, a prepattern 103 is formed on the lower layer film 102 using a composition for forming a prepattern. The pre-pattern 103 controls the phase separation of the self-assembling composition for pattern formation, and a desired fine pattern can be formed. That is, among the polymers contained in the self-assembling composition for pattern formation, a polymer having a high affinity with the side surface of the prepattern forms a phase along the prepattern, and a polymer having a low affinity is obtained from the prepattern. Form a phase at a remote location. Thereby, a desired pattern can be formed. Further, the phase separation structure formed by the self-assembling composition for pattern formation can be finely controlled by the material, length, thickness, shape and the like of the prepattern. The pre-pattern can be appropriately selected according to the pattern to be finally formed. For example, a line and space pattern, a hole pattern, a pillar pattern, or the like can be used.

As a method for forming the pre-pattern 103, a method similar to a known resist pattern forming method can be used. Further, as the pre-pattern forming composition, a conventional resist film-forming composition can be used. As a specific method for forming the pre-pattern 103, for example, a chemically amplified resist composition such as ARX2928JN (manufactured by JSR) is used and applied onto the lower layer film 102 to form a resist film. Next, immersion exposure is performed by irradiating a desired region of the resist film with radiation through a mask having a specific pattern. Examples of the radiation include ultraviolet rays, far ultraviolet rays, X-rays, and charged particle beams. Among these, far ultraviolet rays represented by ArF excimer laser and KrF excimer laser are preferable, and ArF excimer laser is more preferable. Next, post-exposure baking (PEB) is performed, and development is performed using a developer such as an alkali developer, so that a desired pre-pattern 103 can be formed.

The surface of the pre-pattern 103 may be subjected to a hydrophobic treatment or a hydrophilic treatment. As a specific treatment method, a hydrogenation treatment by exposing to hydrogen plasma for a certain period of time can be cited. By increasing the hydrophobicity or hydrophilicity of the surface of the pre-pattern 103, self-organization of the self-assembling composition for pattern formation can be promoted.

[(1) Process]
This step is a step of forming a self-assembled film having a phase separation structure on a substrate using the self-assembled composition for pattern formation. When the lower layer film and the pre-pattern are not used, the self-assembled composition for pattern formation is directly applied on the substrate to form a coating film, thereby forming a self-assembled film having a phase separation structure. Further, when using the lower layer film and the pre-pattern, a coating film is formed by applying the self-assembling composition for pattern formation to a region on the lower layer film delimited by the pre-pattern, and a phase separation structure is formed. A self-assembled film is formed. From the viewpoint that the phase separation structure of the self-assembled film can be precisely controlled, a method using the lower layer film and the prepattern is preferable.

The formation of the self-assembled film 105 follows the principle described in the report by Walheim et al. (Macromolecules, vol. 30, pp. 4995-5003, 1997). That is, by applying a solution containing two or more kinds of polymers incompatible with each other on a substrate and performing annealing or the like, polymers having the same properties accumulate to form an ordered pattern spontaneously. Self-organization can be promoted. As a result, a phase separation structure is formed on the substrate 101. This phase separation structure is preferably formed along the pre-pattern, and the interface formed by phase separation is more preferably substantially parallel to the side surface of the pre-pattern. For example, when the affinity between the prepattern 103, which is a line pattern, and [B] polysiloxane is high, a phase of [B] polysiloxane is formed along the prepattern 103 (105b), and [B] polysiloxane is formed. [A] The phase of the polymer incompatible with A is formed in the part farthest from the side of the pre-pattern, that is, the central part of the area delimited by the pre-pattern (105a), and the lamellar (plate-like) phase is formed An alternating lamellar phase separation structure is formed. When the prepattern is a hole pattern, a [B] polysiloxane phase is formed along the hole side surface of the prepattern, and [B] polysiloxane is incompatible with [B] polysiloxane at the center of the hole. A polymer phase is formed. Further, when the pre-pattern is a pillar pattern, a [B] polysiloxane phase is formed along the side surface of the pre-pattern pillar, and a [A] polymer phase is formed at a portion away from each pillar. Is done. A desired phase separation structure can be formed by appropriately adjusting the distance between the pillars of the pre-pattern and the blending ratio of each polymer of the self-assembling composition for pattern formation. Note that the phase separation structure formed in this step is composed of a plurality of phases, and the interface formed from these phases is usually substantially vertical, but the interface itself is not necessarily clear. Thus, the desired fine pattern can be obtained by precisely controlling the obtained phase separation structure by the blending ratio of each polymer, the pre-pattern, the lower layer film, and the like. By using the self-assembling composition for pattern formation in this step, phase separation is likely to occur, so that a finer phase separation structure (microdomain structure) can be formed.

The method for forming the coating film 104 by applying the self-assembling composition for pattern formation onto a substrate is not particularly limited. For example, the self-assembling composition for pattern formation to be used is applied by a spin coating method or the like. Methods and the like. Thereby, the self-assembling composition for pattern formation is applied between the prepatterns 103 on the substrate 101 or the lower layer film 102 to form a coating film.

As an annealing method, for example, a method of heating at a temperature of 80 ° C. to 400 ° C. by an oven, a hot plate or the like can be mentioned. The annealing time is usually 10 seconds to 30 minutes, preferably 30 seconds to 10 minutes. The film thickness of the self-assembled film 105 thus obtained is preferably 0.1 nm to 500 nm, and more preferably 0.5 nm to 100 nm.

[(2) Process]
This step is a step of removing the phase 105a and / or the pre-pattern 103 made of [B] polysiloxane in the phase separation structure of the self-assembled film 105 as shown in FIGS. The phase 105a and / or the pre-pattern 103 made of the [A] polymer can be removed by etching using the difference in the etching rate of each phase separated by self-organization. FIG. 5 shows a state after the phase 105a and the prepattern 103 made of the [A] polymer in the phase separation structure are removed.

As a method for removing the phase 105a composed of the polymer [A] or the prepattern 103 in the phase separation structure of the self-assembled film 105, for example, reactive ion etching (RIE) such as chemical dry etching or chemical wet etching. ); Known methods such as physical etching such as sputter etching and ion beam etching.
Of these, reactive ion etching (RIE) is preferable. Among these, chemical dry etching using CF ₄ , O ₂ gas, etc., organic solvents such as methyl isobutyl ketone (MIBK) and 2-propanol (IPA), hydrofluoric acid Chemical wet etching (wet development) using a liquid etching solution such as is more preferable.

[(3) Process]
In this step, after the step (2), patterning is performed by etching the lower layer film and the substrate using the pattern made of the phase 105b made of [B] polysiloxane which is a part of the block phase of the remaining phase separation film as a mask. It is a process. After the patterning on the substrate is completed, the phase used as a mask is removed from the substrate by dissolution treatment or the like, and a finally patterned substrate (pattern) can be obtained. As the etching method, the same method as in step (2) can be used, and the etching gas and the etching solution can be appropriately selected depending on the material of the lower layer film and the substrate. For example, when the substrate is a silicon material, a mixed gas of chlorofluorocarbon gas and SF ₄ or the like can be used. When the substrate is a metal film, a mixed gas of BCl ₃ and Cl ₂ or the like can be used. The pattern obtained by the pattern forming method is preferably used for a semiconductor element and the like, and the semiconductor element is widely used for an LED, a solar cell, and the like.

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. *

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) using Tosoh GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under the following conditions.
Eluent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[ ¹³ C-NMR analysis]:
^{The 13} C-NMR analysis was performed using JNM-EX400 manufactured by JEOL Ltd. and DMSO-d ₆ as the measurement solvent. The content 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 ¹³ C-NMR.

<[A] Synthesis of polymer>
[Synthesis Example 1]
After drying the 1 L flask reaction vessel under reduced pressure, 500 g of cyclohexane subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to 0 ° C. Thereafter, 4.40 mL of sec-butyllithium (cyclohexane solution: 1.8 mol / L) was injected, and 40 g of styrene subjected to distillation dehydration was added dropwise over 30 minutes. After completion of the dropping, the mixture was aged for 60 minutes, and 1 g of 1,2-butylene oxide was injected as a terminal treating agent to react. The reaction solution was warmed to room temperature, concentrated, and replaced with propylene glycol methyl ether acetate (PGMEA). Thereafter, 1,000 g of a 2% oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times, and after removing the lithium salt, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. This operation was repeated 3 times, and oxalic acid was removed. Then, the solution was concentrated and dropped into 500 g of n-hexane to precipitate a polymer. The polymer filtered under reduced pressure was washed twice with n-hexane and then dried under reduced pressure at 60 ° C. to obtain 10.5 g of a white polymer (A-1).
Mw of the polymer (A-1) was 5,000, and Mw / Mn was 1.13.

[Synthesis Examples 2 to 9]
Polymers (A-2) to (A-8) and (A-8) and (A-8) and (A) a-1) was synthesized. Mw and Mw / Mn of each polymer are shown in Table 1.

[Synthesis Example 10]
100 g of phenyl methacrylate as a monomer compound is dissolved in 200 g of 2-butanone, and VA-086 as a radical polymerization initiator (2,2′-azobis [2-methyl-N- (2-hydroxyethyl) manufactured by Wako Pure Chemical Industries, Ltd. ) Propionamide]) 7.10 g (5 mol% based on monomer compound) was added to prepare a monomer solution. A 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the monomer solution prepared above was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. This cooled polymerization reaction liquid was put into 1,500 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 300 g of methanol and then separated and dried at 50 ° C. for 17 hours to obtain 71.3 g of a white polymer (A-9).
Mw of the polymer (A-9) was 5,000, and Mw / Mn was 1.23. The structure of the radical polymerization initiator VA-086 is as shown in the following formula (i). The polymer (A-9) has a structure represented by the following formula (ii) at the end of the main chain.

In the above formula (ii), * indicates a site bonded to the carbon atom at the end of the main chain of the polymer.

[Synthesis Examples 11 to 12]
Polymers (A-10) and (A-11) were synthesized by the same method as in Synthesis Example 10 except that the types of the monomer compound and the radical polymerization initiator were as described in Table 2. Mw and Mw / Mn of each polymer are shown in Table 2. The structure of the radical polymerization initiator VA-061 (manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis [2- (2-imidazolin-2-yl) propane]) used in Synthesis Example 11 is represented by the following formula ( iii). The polymer (A-10) has a structure represented by the following formula (iv) at the end of the main chain, and the polymer (A-11) is represented by the above formula (ii) at the end of the main chain. It has the structure represented.

In the above formula (iv), * indicates a site bonded to the carbon atom at the end of the main chain of the polymer.

<[B] Synthesis of polysiloxane>
[B] Hydrolyzable silane compounds (M-1) to (M-3) used for the synthesis of polysiloxane were represented by the following formulae.

[Synthesis Example 13]
A maleic acid aqueous solution was prepared by dissolving 5 g of maleic anhydride in 100 g of water by heating. Next, 23.0 g of phenyltriethoxysilane (M-1), 34.0 g of 4-t-butoxyphenethyltriethoxysilane (M-2), and 500 g of propylene glycol monopropyl ether were placed in the flask. To this flask, the dropping funnel containing the maleic acid aqueous solution prepared in advance was set and heated at 60 ° C. in an oil bath, and then the maleic acid aqueous solution was slowly dropped and reacted at 60 ° C. for 4 hours. . After completion of the reaction, 1.0 g of concentrated hydrochloric acid was added and reacted at 60 ° C. for 1 hour. Next, after cooling the reaction solution, 500 g of PGMEA was added and set in an evaporator to remove methanol and ethanol generated during the reaction. Thereafter, 500 g of water was added to the reaction solution, and the acid was extracted, washed, and then concentrated by an evaporator to obtain a polymer (B-1). The polymer (B-1) had a solid content concentration of 15% by mass, Mw of 2,000, and Mw / Mn of 1.13. In the present specification, the “solid content” means a residue obtained by drying a sample on a hot plate at 175 ° C. for 1 hour to remove volatile substances.
Content rate (mol%) of structural units derived from phenyltriethoxysilane determined from ¹ H-NMR and FT-IR: Content (mol%) of structural units derived from 4-t-butoxyphenethyltriethoxysilane is 30 (mol%): 70 (mol%).

[Synthesis Examples 14 to 18]
Polymers (B-2) to (B-6) were obtained in the same manner as in Synthesis Example 13, except that the types and amounts of the monomers used were as shown in Table 3. The Mw and Mw / Mn of each polymer and the content of each structural unit are shown in Table 3.

<Preparation of self-assembling composition for pattern formation>
[Example 1]
Polymer (A-1) and polymer (B-1) were mixed at a mass ratio of 4: 6 to prepare a PGMEA solution having a concentration of 1% by mass. This solution was filtered through a membrane filter having a pore diameter of 200 nm to prepare a self-assembling composition for pattern formation, and a pattern was formed by the following method.

[Examples 2 to 17 and Comparative Example 1]
A self-assembling composition for pattern formation was prepared in the same manner as in Example 1 except that the type of polymer used was as shown in Table 4, and a pattern was formed by the following method.

<Pattern formation method>
A 12-inch silicon wafer was spin-coated with an underlayer film (ARC66, manufactured by Brewer Science) using CLEAN TRACK ACT12 (manufactured by Tokyo Electron), and then baked at 205 ° C. to form an underlayer film having a thickness of 77 nm. . On the formed lower layer film, ARX2928JN (manufactured by JSR) was spin-coated and then PB (120 ° C., 60 seconds) was formed to form a resist film having a thickness of 60 nm. Using an ArF immersion exposure apparatus (NSR S610C, manufactured by Nikon), exposure was performed through a mask pattern under optical conditions of NA: 1.30, CrossPole, and σ = 0.777 / 0.78. Thereafter, PEB was performed at 115 ° C. for 60 seconds, and then developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, washed with water, and dried to obtain a prepattern (60 nm hole / 120 nm Pitch). Subsequently, the prepattern was irradiated with ultraviolet light of 254 nm at 150 mJ / cm ^{2 and then} baked at 170 ° C. for 5 minutes to obtain an evaluation substrate.
Next, each self-assembling composition for pattern formation was applied on the evaluation substrate so as to have a thickness of 15 nm, and baked at 120 ° C. for 1 minute to cause phase separation to form a microdomain structure. Then, it was immersed in cyclohexane for 1 minute, the polystyrene part was removed, and the hole pattern was formed.

<Evaluation>
The pattern formed as described above is observed using a length measuring SEM (S9380, manufactured by Hitachi High-Technologies), and the diameter (nm) of the hole of the obtained pattern is subtracted from the diameter (nm) of the hole of the pre-pattern. The value was determined, and this value was defined as the shrink amount (nm).
The case where the shrink amount (nm) was 10 nm or more was judged good, and the case where it was less than 10 nm was judged as bad. The results are shown in Table 4.

As shown in Table 4, in the case of using the pattern forming self-assembling composition of the example, the hole diameter of the pattern can be made smaller than that of the comparative example, and the micro domain structure is sufficiently fine. Was found to be obtained.

According to the present invention, it is possible to provide a self-assembling composition for pattern formation that can form a pattern having a sufficiently fine microdomain structure, and a pattern forming method using the same. Therefore, the self-assembling composition for pattern formation and the pattern forming method of the present invention are suitably used for lithography processes in the manufacture of various electronic devices such as semiconductor devices and liquid crystal devices that require further miniaturization.

101. Substrate 102. Underlayer film 103. Pre-pattern 104. Coating film 105. Self-assembled film 105a. [A] Phase 105b consisting of polymer b. [B] Phase composed of polysiloxane

Claims (9)

1. [A] A polymer having a hetero atom-containing group (α) at at least one end of the main chain, and [B] a self-assembling composition for pattern formation, containing polysiloxane.
2. The self-assembled composition for pattern formation according to claim 1, wherein the heteroatom is at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a tin atom and a silicon atom.
3. The self-assembling composition for pattern formation according to claim 1, wherein the group (α) is represented by the following formula (1).
   

   

   (In Formula (1), R ¹ is a single bond or a divalent organic group having 1 to 30 carbon atoms. R ² is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms.)
4. The self-assembled composition for pattern formation according to claim 1, wherein the [A] polymer is a styrene polymer.
5. [B] The self-assembling composition for pattern formation according to claim 1, wherein the polysiloxane is a hydrolysis condensate of a hydrolyzable silane compound containing a compound represented by the following formula (2).
   

   

   (In the formula (2), R ³ is an alkyl group having 1 to 8 carbon atoms or an organic group having 6 to 30 carbon atoms including an aromatic ring, provided that a part or all of the hydrogen atoms of the alkyl group are included. R ⁴ represents a chlorine atom or a monovalent group represented by —OR ^5. R ⁵ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms. Or an aryl group having 6 to 15 carbon atoms, provided that a part or all of the hydrogen atoms of the alkyl group, acyl group and aryl group may be substituted. Provided that when a is 2 or more, the plurality of R ³ may be the same or different, and when a is 2 or less, the plurality of R ⁴ may be the same or different. )
6. The self-assembling composition for pattern formation according to claim 1, wherein the content of [B] polysiloxane with respect to 100 parts by mass of [A] polymer is 20 parts by mass or more and 200 parts by mass or less.
7. (1) A step of forming a self-assembled film having a phase separation structure on a substrate using the self-assembled composition for pattern formation according to claim 1, and (2) a part of the self-assembled film The pattern formation method including the process of removing a phase.
8. Before step (1) above,
   (0-1) further comprising a step of forming a lower layer film on the substrate, and (0-2) a step of forming a pre-pattern on the lower layer film,
   The pattern forming method according to claim 7, wherein in the step (1), a self-assembled film is formed in a region on the lower layer film delimited by the prepattern.
9. The pattern forming method according to claim 7, wherein the obtained pattern is a line and space pattern or a hole pattern.

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