JP4844439B2 - Resin composition for forming fine pattern and method for forming fine pattern - Google Patents

Description

  The present invention relates to a fine processing technique using a photoresist, and relates to a resin composition for forming a fine pattern and a method for forming a fine pattern, which are used when a pattern is shrunk by heat treatment after patterning. More specifically, by using an alcohol solvent, wettability to a photoresist pattern is improved, and a pattern having a diameter of 100 nm or less can be easily coated without entraining bubbles, and the resin composition for forming a fine pattern The resin composition for forming a fine pattern that can be used as it is without using a new water-based coating cup or waste liquid treatment equipment, and without using a cup or waste liquid treatment equipment used when applying the lower layer film or photoresist, The present invention relates to a fine pattern forming method.

In recent years, with the progress of miniaturization of semiconductor elements, further miniaturization has been required in the lithography process in the manufacturing method. That is, in the lithography process, microfabrication of 100 nm or less is now required, and a fine pattern is formed using a photoresist material corresponding to short-wavelength irradiation light such as ArF excimer laser light and F ₂ excimer laser light. Various methods for forming the film have been studied.
In such a lithography technique, there is an unavoidable limitation in miniaturization due to the limitation of the exposure wavelength, so far, research has been conducted to enable the formation of a fine pattern exceeding the wavelength limit. I came. That is, after patterning an electron beam resist such as polymethyl methacrylate and applying a positive resist on the resist pattern, a heat treatment is performed to provide a reaction layer at the boundary between the resist pattern and the positive resist layer. A method of refining a resist pattern by removing non-reacted portions of the resist (Patent Document 1), and forming a reaction layer between the lower layer resist pattern and the upper layer resist using thermal crosslinking with an acid generator or acid (Patent Document 2), as an upper layer resist coating solution, a semiconductor device using a fine pattern forming material in which a photosensitive component is not contained and a water-soluble resin, a water-soluble crosslinking agent, or a mixture thereof is dissolved in a water-soluble solvent (Patent Document 3), a photosensitive layer made of a chemically amplified resist is provided on a substrate, and after image-exposure exposure, development processing is performed. A water-soluble resin such as polyvinyl acetal, a water-soluble cross-linking agent such as tetra (hydroxymethyl) glycoluril, a water-soluble nitrogen-containing organic compound such as amine, and the like. After applying a film-forming agent containing a fluorine-containing and silicon-containing surfactant, a heat treatment is performed to form a water-insoluble reaction layer at the interface between the resist pattern and the resist pattern refinement coating, and then with pure water A method (Patent Document 4) and the like for removing a non-reacted portion of a resist pattern refinement coating film have been proposed.

  These methods are preferable in that the pattern of the resist pattern (lower layer resist) can be easily refined beyond the wavelength limit of the photosensitive resist (upper layer resist). Cross-linking of the fine pattern forming material up to the unnecessary part of the bottom part, a skirted shape, the perpendicularity of the cross-sectional shape of the fine pattern forming material is poor, or the upper resist pattern size is cross-linked However, there is a problem that the pattern shape is influenced by mixing baking, which is a heating for heating, and it cannot be said that it is sufficiently satisfactory. In addition, these processes are highly dependent on heat of several tens of nm / ° C., and it is difficult to maintain a uniform temperature in the wafer surface when the substrate is enlarged and the pattern is miniaturized. There is a problem that the dimensional controllability of the lowering. Furthermore, the fine pattern forming material using the above water-soluble resin has a problem of low resistance to dry etching due to the limitation of solubility in water. When creating a semiconductor device, the pattern is transferred onto the substrate by dry etching using the resist pattern as a mask. However, if the dry etching resistance is low, there is a problem that the resist pattern cannot be accurately transferred onto the substrate.

  In addition, a so-called thermal flow process has been proposed in which a photoresist pattern is formed on a substrate and then subjected to heat or radiation to fluidize the photoresist pattern to make the pattern dimension smaller than the resolution limit ( Patent Document 5 and Patent Document 6).

  However, this method has a problem that it is difficult to control the flow of resist by heat or radiation, and a product having a constant quality cannot be obtained. Furthermore, as a method developed from this thermal flow process, a method of forming a photoresist pattern on a substrate and then providing a water-soluble resin film thereon to control the flow of the photoresist is proposed (Patent Document 7). However, the water-soluble resin such as polyvinyl alcohol used in this method has a drawback that it has insufficient solubility and stability over time required for removal with water, and a residue is generated.

Alternatively, when a fine resist pattern is formed by thermally shrinking a resist pattern formed using a photoresist, a coating formation agent on the resist pattern is provided, the resist pattern is thermally contracted by heat treatment, and removed by washing with water. A resist pattern refinement coating forming agent to be obtained and a method for efficiently forming a fine resist pattern using the same (Patent Document 8) have been proposed. In this method, the resist pattern refinement coating forming agent is an aqueous system. The coating on fine patterns such as contact holes with a diameter of 100 nm or less is insufficient, and since it is water-based, a dedicated cup is required at the time of coating, which increases the cost. In this case, there is a problem that freezing and precipitation occur.
In order to cope with the above problems, the present inventors can efficiently shrink a resist pattern by heat treatment and can be easily removed by subsequent alkaline aqueous solution treatment, and use this efficiently. An application has been filed for a fine pattern forming method capable of forming a fine resist pattern (Patent Document 9). However, there is a problem that the shrinkage rate is further improved and the pattern shape after shrinkage is required to be more stable, but the conventional technique is not sufficient.
Japanese Patent No. 2723260 JP-A-6-250379 Japanese Patent Laid-Open No. 10-73927 Japanese Patent Laid-Open No. 2001-19860 JP-A-1-307228 Japanese Patent Laid-Open No. 4-364221 JP 7-45510 A JP 2003-195527 A WO2005 / 1167676 A1

  The present invention has been made to cope with such a problem. When a fine pattern is formed by heat-treating a resist pattern formed using a photoresist, the fine-pattern is applied on the resist pattern, and the heat-treatment is performed by heat treatment. The present invention provides a resin composition that can smoothly and stably shrink a resist pattern and can be easily removed by subsequent alkaline aqueous solution treatment, and a fine pattern forming method that can efficiently form a fine resist pattern using the resin composition With the goal.

式（１）において、Ｒ¹は水素原子、メチル基、またはトリフルオロメチル基を表し、Ｒ²は水素原子、直鎖状アルコキシル基、または水酸基を表し、Ｒ²が水素原子または水酸基の場合、ｎは２〜８の整数であり、Ｒ²が直鎖状アルコキシル基の場合、ｎは２〜７の整数であり、該直鎖状アルコキシル基の炭素数を含めて、−（ＣＨ₂）ｎ−Ｒ²基の炭素数が２〜８である。
また、上記樹脂がフェノール類およびカルボン酸類に由来する水酸基から選ばれる少なくとも１つの水酸基を含む繰り返し単位（ＩＩ）を含むことを特徴とする。
また、上記樹脂が、下記式（２）で表される繰り返し単位（ＩＩＩ）を含有することを特徴とする。

式（２）において、Ｒ³は水素原子、炭素数１〜８の直鎖状もしくは分岐状のアルキル基、または炭素数１〜８の直鎖状もしくは分岐状のアルコキシル基を表す。 The resin composition for forming a fine pattern of the present invention is a resin composition for forming a fine pattern, which contains a resin, a crosslinking component that crosslinks the resin, and a solvent, and for refining a resist pattern. Contains the repeating unit (I) represented by the following formula (1). In particular, 3-30 mol% is contained with respect to all the monomers which comprise resin.

In Formula (1), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R ² represents a hydrogen atom, a linear alkoxyl group, or a hydroxyl group, and when R ² is a hydrogen atom or a hydroxyl group, n is an integer of 2 to 8, and when R ² is a linear alkoxyl group, n is an integer of 2 to 7, including the carbon number of the linear alkoxyl group, — (CH ₂ ) n -R < ² > group has 2-8 carbon atoms.
In addition, the resin includes a repeating unit (II) containing at least one hydroxyl group selected from hydroxyl groups derived from phenols and carboxylic acids.
Moreover, the said resin contains repeating unit (III) represented by following formula (2), It is characterized by the above-mentioned.

In the formula (2), R ³ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxyl group having 1 to 8 carbon atoms.

式（３）において、Ｒ⁴およびＲ⁵は、水素原子または下記式（４）で表され、Ｒ⁴およびＲ⁵の少なくとも１つは下記式（４）で表され；

式（４）において、Ｒ⁶およびＲ⁷は、水素原子、炭素数１〜６のアルキル基、炭素数１〜６にアルコキシアルキル基、またはＲ⁶およびＲ⁷が互いに連結した炭素数２〜１０の環を表し、Ｒ⁸は、水素原子、炭素数１〜６のアルキル基を表す。
また、本発明の微細パターン形成用樹脂組成物に用いられる溶媒が炭素数１〜８の１価アルコールであることを特徴とする。 The crosslinking component that crosslinks the resin used in the resin composition for forming a fine pattern of the present invention includes a compound containing a group represented by the following formula (3) and a compound containing two or more cyclic ethers as reactive groups. It is characterized by being at least one selected compound.

In the formula (3), R ⁴ and R ⁵ are represented by a hydrogen atom or the following formula (4), and at least one of R ⁴ and R ⁵ is represented by the following formula (4);

In Formula (4), R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, or 2 to 10 carbon atoms in which R ⁶ and R ⁷ are linked to each other. R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Moreover, the solvent used for the resin composition for forming a fine pattern of the present invention is a monohydric alcohol having 1 to 8 carbon atoms.

  The fine pattern forming method of the present invention includes a pattern forming step of forming a resist pattern on a substrate, a coating step of providing the above-described resin composition for forming a fine pattern of the present invention on the resist pattern, and the coating step It includes a step of heat-treating the subsequent substrate, and a step of removing the film with an alkaline aqueous solution and washing with water.

Since the resin composition for forming a fine pattern of the present invention contains a resin having the above formula (1) as a repeating unit, a crosslinking component, and a solvent, it has excellent coating properties for a fine resist pattern and has a cured film. Excellent dimensional control. Therefore, regardless of the surface state of the substrate, the pattern gap of the resist pattern can be effectively and accurately miniaturized, and the pattern exceeding the wavelength limit can be satisfactorily and economically reduced with few pattern defects. It can be formed in a state.
In particular, the resin composition for forming a fine pattern of the present invention has a large amount of shrinkage of the resin, low temperature dependence at the time of shrinkage, excellent shape after shrinkage, and low pitch dependence. The process window (also called Exposure Depth-Window), which is a margin, is wide. Moreover, it is excellent in etching resistance.
Furthermore, by performing dry etching using the fine resist pattern thus formed as a mask, a trench pattern and a hole can be formed with high precision on a semiconductor substrate, and a semiconductor device having a fine trench pattern and a hole can be easily obtained. In addition, it can be manufactured with good yield.

式（１）において、Ｒ¹は水素原子、メチル基、またはトリフルオロメチル基を表し、Ｒ²は水素原子、直鎖状アルコキシル基、または水酸基を表し、Ｒ²が水素原子または水酸基の場合、ｎは２〜８の整数であり、Ｒ²が直鎖状アルコキシル基の場合、ｎは２〜７の整数であり、該直鎖状アルコキシル基の炭素数を含めて、−（ＣＨ₂）ｎ−Ｒ²基の炭素数が２〜８である。 As a result of intensive research on a resin composition that can smoothly shrink a resist pattern by heat treatment and can be easily removed by subsequent alkaline aqueous solution treatment, the present inventors have found that it is not water-soluble resin but alcohol-soluble. It has been found that a fine pattern can be efficiently formed by using a resin composition containing a specific resin, a crosslinking component, and a solvent, and the present invention has been completed based on this finding.
The resin composition for forming a fine pattern of the present invention is a composition comprising a resin, a crosslinking component, and a solvent. The resin is a resin containing 3 to 30 mol%, preferably 8 to 12 mol%, of the repeating unit (I) represented by the following formula (1) with respect to all monomers constituting the resin. When the repeating unit (I) is less than 3 mol%, the shrinkage dimension amount does not increase, and when it exceeds 30 mol%, the shrinkage dimension amount increases excessively.

In Formula (1), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R ² represents a hydrogen atom, a linear alkoxyl group, or a hydroxyl group, and when R ² is a hydrogen atom or a hydroxyl group, n is an integer of 2 to 8, and when R ² is a linear alkoxyl group, n is an integer of 2 to 7, including the carbon number of the linear alkoxyl group, — (CH ₂ ) n -R < ² > group has 2-8 carbon atoms.

In the case where R ² is a hydrogen atom or a hydroxyl group, an integer linear alkyl group having n of 2 to 8 includes an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-heptyl group, An n-octyl group may be mentioned.
In the case where R ² is a linear alkoxyl group, examples of the linear alkoxyl group include a methoxyl group to a heptoxyl group, including the carbon number of the linear alkoxyl group, — (CH ₂ ) nR ^Two groups have 2 to 8 carbon atoms. That is, in the case of a methoxyl group, n is 2 to 7, and in the case of a heptoxyl group, n is 2.

The repeating unit (I) represented by the formula (1) can be obtained by polymerizing a (meth) acrylic acid derivative as a monomer.
As a monomer which produces | generates the repeating unit (I) represented by Formula (1), ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) Acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 4-methoxybutyl ( (Meth) acrylate, 5-methoxypentyl (meth) acrylate, 6-methoxyhexyl (meth) acrylate, 7-methoxyheptyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate, 5- Toxipentyl (meth) acrylate, 6-ethoxyhexyl (meth) acrylate, 2-n-propoxyethyl (meth) acrylate, 3-n-propoxypropyl (meth) acrylate, 4-n-propoxybutyl (meth) acrylate, 5-n-propoxypentyl (meth) acrylate, 2-n-butoxyethyl (meth) acrylate, 3-n-butoxypropyl (meth) acrylate, 4-n-butoxybutyl (meth) acrylate, 2-n-pentoxy Ethyl (meth) acrylate, 3-n-pentoxypropyl (meth) acrylate, 2-n-heptoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxy-n-pentyl (meth) acrylate, hydroxy-n-butyl (Meta) Acrelay , Hydroxy -n- pentyl (meth) acrylate, hydroxy -n- hexyl (meth) acrylate, hydroxy -n- heptyl (meth) acrylate, hydroxy -n- octyl (meth) acrylate.
Among these, n-butyl methacrylate, n-hexyl methacrylate, n-octyl acrylate, 2-methoxymethyl acrylate, and hydroxybutyl acrylate are preferable.

  The resin that can be used in the present invention can contain a repeating unit (II) containing at least one hydroxyl group selected from hydroxyl groups derived from phenols and carboxylic acids, except for the hydroxyl group derived from the repeating unit (I). The repeating unit (II) can be obtained by copolymerizing a monomer having at least one hydroxyl group among a hydroxyl group derived from a carboxylic acid and a phenolic hydroxyl group.

Examples of the monomer containing a hydroxyl group derived from an organic acid such as carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, 2-succinoloylethyl (meth) acrylate, 2-malenoylethyl (meth) acrylate, 2 -Hexahydrophthaloylethyl (meth) acrylate, ω-carboxy-polycaprolactone monoacrylate, monohydroxyethyl acrylate phthalate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, t-butoxy methacrylate, t-butyl acrylate Monocarboxylic acids such as: (meth) acrylic acid derivatives having a carboxyl group such as dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid, and the like. Or 2 It can be used in combination or more. As a commercially available product of ω-carboxy-polycaprolactone monoacrylate, for example, Aronix M-5300 manufactured by Toagosei Co., Ltd., and as a commercially available product of acrylic acid dimer, for example, Aronix M-5600 manufactured by the same company, 2-hydroxy Examples of commercially available products of -3-phenoxypropyl acrylate include Aronix M-5700 manufactured by the same company.
Among these, acrylic acid, methacrylic acid, and 2-hexahydrophthaloylethyl methacrylate are preferable. These monomers are usually 5 to 90 mol%, preferably 10 to 60 mol%, based on all monomers constituting the resin.

  Examples of the monomer having a phenolic hydroxyl group include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, α-methyl-p-hydroxystyrene, α-methyl-m-hydroxystyrene, α-methyl-o-. Hydroxystyrene, 2-allylphenol, 4-allylphenol, 2-allyl-6-methylphenol, 2-allyl-6-methoxyphenol, 4-allyl-2-methoxyphenol, 4-allyl-2,6-dimethoxyphenol 4-allyloxy-2-hydroxybenzophenone and the like, among which p-hydroxystyrene or α-methyl-p-hydroxystyrene is preferable.

Ｒ⁹およびＲ¹¹は水素原子またはメチル基を表し、Ｒ¹⁰は、単結合または直鎖状または環状の２価の炭化水素基を表す。
Ｒ¹⁰としては、メチレン基、エチレン基、プロピレン基（１，３−プロピレン基、１，２−プロピレン基）、テトラメチレン基、ペンタメチレン基、ヘキサメチレン基、ヘプタメチレン基、オクタメチレン基、ノナメチレン基、デカメチレン基、ウンデカメチレン基、ドデカメチレン基、トリデカメチレン基、テトラデカメチレン基、ペンタデカメチレン基、ヘキサデカメチレン基、ヘプタデカメチレン基、オクタデカメチレン基、ノナデカメチレン基、インサレン基、１−メチル−１，３−プロピレン基、２−メチル−１，３−プロピレン基、２−メチル−１，２−プロピレン基、１−メチル−１，４−ブチレン基、２−メチル−１，４−ブチレン基、エチリデン基、プロピリデン基、２−プロピリデン基等の飽和鎖状炭化水素基、１，３−シクロブチレン基などのシクロブチレン基、１，３−シクロペンチレン基などのシクロペンチレン基、１，４−シクロヘキシレン基などのシクロヘキシレン基、１，５−シクロオクチレン基などのシクロオクチレン基等、炭素数３〜１０のシクロアルキレン基などの単環式炭化水素環基、１，４−ノルボルニレン基や２，５−ノルボルニレン基などのノルボルニレン基、１，５−アダマンチレン基や２，６−アダマンチレン基などのアダマンチレン基等の２ないし４環式の炭素数４〜３０の炭化水素環基などの架橋環式炭化水素環基を挙げることができる。
式（５）で表される単量体としては、ｐ−ヒドロキシメタクリルアニリドが好ましい。式（５）で表されるフェノール性水酸基を有する単量体は、樹脂を構成する全単量体に対して、通常３０〜９５モル％、好ましくは４０〜９０モル％である。 Moreover, the monomer represented by following formula (5) which has an amide group in a molecule | numerator as a preferable monomer which has a phenolic hydroxyl group is mentioned.

R ⁹ and R ¹¹ represent a hydrogen atom or a methyl group, and R ¹⁰ represents a single bond or a linear or cyclic divalent hydrocarbon group.
R ¹⁰ includes methylene group, ethylene group, propylene group (1,3-propylene group, 1,2-propylene group), tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene. Group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group, octadecamethylene group, nonacamethylene group, insalen Group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl- Saturated chain hydrocarbon group such as 1,4-butylene group, ethylidene group, propylidene group, 2-propylidene group, 1,3 Cyclobutylene groups such as cyclobutylene groups, cyclopentylene groups such as 1,3-cyclopentylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, and cyclooctylene groups such as 1,5-cyclooctylene groups A monocyclic hydrocarbon ring group such as a cycloalkylene group having 3 to 10 carbon atoms, a norbornylene group such as a 1,4-norbornylene group or a 2,5-norbornylene group, a 1,5-adamantylene group, Examples thereof include a bridged cyclic hydrocarbon ring group such as a bicyclic to tetracyclic hydrocarbon ring group having 4 to 30 carbon atoms such as an adamantylene group such as a 6-adamantylene group.
As the monomer represented by the formula (5), p-hydroxymethacrylanilide is preferable. The monomer having a phenolic hydroxyl group represented by the formula (5) is usually 30 to 95 mol%, preferably 40 to 90 mol%, based on all monomers constituting the resin.

  Furthermore, a monomer having a functional group that can be converted into a phenolic hydroxyl group after copolymerization can be copolymerized. For example, p-acetoxystyrene, α-methyl-p-acetoxystyrene, p-benzyloxystyrene, p -Tert-butoxystyrene, p-tert-butoxycarbonyloxystyrene, p-tert-butyldimethylsiloxystyrene and the like. When these functional group-containing compounds are used, the obtained resin can be easily converted into a phenolic hydroxyl group by appropriate treatment, for example, hydrolysis using hydrochloric acid or the like. it can. The monomers before and after conversion to these phenolic hydroxyl groups are usually 5 to 90 mol%, preferably 10 to 80 mol%, based on all monomers constituting the resin.

  These monomers having an alcoholic hydroxyl group, a hydroxyl group derived from a carboxylic acid, or a phenolic hydroxyl group are within the above ranges with respect to all monomers constituting the resin. If the number of structural units having a hydroxyl group is too small, the number of reaction sites with the crosslinking component described later is too small to cause pattern shrinkage. On the other hand, if too large, there is a risk of swelling during development and filling the pattern. .

式（２）において、Ｒ³は水素原子、炭素数１〜８の直鎖状もしくは分岐状のアルキル基、または炭素数１〜８の直鎖状もしくは分岐状のアルコキシル基を表す。
好ましいＲ³としては、ｔｅｒｔ−ブチル基、アセトキシ基、１−エトキシエトキシ基であり、最も好ましくはｔｅｒｔ−ブチル基である。
繰り返し単位（ＩＩＩ）は、単量体としてスチレン誘導体を共重合することにより得られる。好ましい単量体はｔｅｒｔ−ブトキシスチレンである。
繰り返し単位（ＩＩＩ）を生成する単量体は樹脂を構成する全単量体に対して、通常１０〜８０モル％、好ましくは２０〜５０モル％である。１０モル％未満では収縮寸法が増加せず、８０モル％をこえると現像液に対する溶解性が悪くなる。 The resin that can be used in the present invention preferably further contains a repeating unit (III) represented by the following formula (2).

In the formula (2), R ³ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxyl group having 1 to 8 carbon atoms.
R ³ is preferably a tert-butyl group, an acetoxy group, or a 1-ethoxyethoxy group, and most preferably a tert-butyl group.
The repeating unit (III) can be obtained by copolymerizing a styrene derivative as a monomer. A preferred monomer is tert-butoxystyrene.
The monomer for forming the repeating unit (III) is usually 10 to 80 mol%, preferably 20 to 50 mol%, based on all monomers constituting the resin. If the amount is less than 10 mol%, the shrinkage dimension does not increase, and if it exceeds 80 mol%, the solubility in the developer deteriorates.

  In addition, other monomers can be copolymerized with the resin for the purpose of controlling the hydrophilicity and solubility of the resin. As other monomers, monomers other than the above components, such other monomers include (meth) acrylic acid aryl esters, dicarboxylic acid diesters, nitrile group-containing polymerizable compounds, Examples include amide bond-containing polymerizable compounds, vinyls, allyls, chlorine-containing polymerizable compounds, and conjugated diolefins. Specifically, dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate; (meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate; aromatic vinyl such as vinyltoluene , Methacrylic acid esters such as t-butyl (meth) acrylate, 4,4,4-trifluoro-3-hydroxy-1-methyl-3-trifluoromethyl-1-butyl (meth) acrylate; acrylonitrile Nitrile group-containing polymerizable compounds such as methacrylonitrile; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; fatty acid vinyls such as vinyl acetate; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; -Butadiene, isoprene, 1,4- It can be used conjugated diolefins such as methyl butadiene. These compounds can be used alone or in combination of two or more.

The above resin, for example, using a mixture of monomers, radical polymerization initiators such as hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, and the presence of a chain transfer agent if necessary Then, it can be produced by polymerization in an appropriate solvent.
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; cyclohexane, cycloheptane, cyclooctane, decalin, Cycloalkanes such as norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene; ethyl acetate Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate, methyl propionate, propylene glycol monomethyl ether acetate; alkyl lactones such as γ-butyrolactone; tetrahydrofuran, dimethoxyethanes, diethoxyethanes, etc. Ethers; alkyl ketones such as 2-butanone, 2-heptanone and methyl isobutyl ketone; cycloalkyl ketones such as cyclohexanone; 2-propanol, 1-butanol, 4-methyl-2-pentanol, propylene glycol monomethyl ether, etc. Alcohols and the like. These solvents can be used alone or in combination of two or more.

  Moreover, the reaction temperature in the said superposition | polymerization is 40-120 degreeC normally, Preferably it is 50-100 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours.

The resin preferably has a high purity, and not only the content of impurities such as halogen and metal is low, but the residual monomer and oligomer components are not more than predetermined values, for example, 0.1% by mass or less by HPLC analysis, etc. It is preferable that As a result, not only can the process stability, pattern shape, etc. of the resin composition for fine pattern formation of the present invention containing a resin be further improved, but there is no change over time such as foreign matter in liquid or sensitivity. A resin composition can be provided.
The following method is mentioned as a purification method of resin obtained by the above methods. As a method for removing impurities such as metals, a method in which a metal in a polymerization solution is adsorbed using a zeta potential filter, a metal is chelated and removed by washing the polymerization solution with an acidic aqueous solution such as oxalic acid or sulfonic acid. And the like. In addition, as a method of removing residual monomers and oligomer components below the specified value, liquid-liquid extraction method that removes residual monomers and oligomer components by combining water washing and an appropriate solvent, a specific molecular weight or less Refining method to remove residual monomers by coagulating resin in poor solvent by dripping polymerization solution into poor solvent And a purification method in a solid state such as washing with a poor solvent for the resin slurry separated by filtration. Moreover, you may combine these methods.

  The weight average molecular weight Mw of the resin thus obtained is usually 1,000 to 500,000, preferably 1,000 to 50,000, particularly preferably 1,000 to 20,000 in terms of polystyrene by gel permeation chromatography. It is. If the molecular weight is too large, there is a possibility that it cannot be removed with a developer after thermosetting, and if it is too small, a uniform coating film may not be formed after coating.

式（３）において、Ｒ⁴およびＲ⁵は、水素原子または下記式（４）で表され、Ｒ⁴およびＲ⁵の少なくとも１つは下記式（４）で表され；

式（４）において、Ｒ⁶およびＲ⁷は、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシアルキル基、またはＲ⁶およびＲ⁷が互いに連結した炭素数２〜１０の環を表し、Ｒ⁸は、水素原子、炭素数１〜６のアルキル基を表す。
上記架橋成分は上述した樹脂および／または架橋成分が相互に酸の作用により反応する架橋成分（硬化成分）として作用するものである。 The crosslinking component used in the present invention includes a compound containing a group represented by the following formula (3) (hereinafter referred to as “crosslinking component I”) and a compound containing two or more cyclic ethers as reactive groups (hereinafter referred to as “ Or a mixture of “crosslinking component I” and “crosslinking component II”.

In the formula (3), R ⁴ and R ⁵ are represented by a hydrogen atom or the following formula (4), and at least one of R ⁴ and R ⁵ is represented by the following formula (4);

In Formula (4), R ⁶ and R ⁷ are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, or 2 to 10 carbon atoms in which R ⁶ and R ⁷ are linked to each other. R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The crosslinking component functions as a crosslinking component (curing component) in which the above-described resin and / or crosslinking component react with each other by the action of an acid.

The compound represented by formula (3) (crosslinking component I) is a compound having an imino group, a methylol group, a methoxymethyl group or the like as a functional group in the molecule, and (poly) methylol melamine, (poly) methylol Examples thereof include nitrogen-containing compounds obtained by alkyl etherifying all or part of active methylol groups such as glycoluril, (poly) methylolated benzoguanamine, and (poly) methylolated urea. Here, examples of the alkyl group include a methyl group, an ethyl group, a butyl group, or a mixture thereof, and may contain an oligomer component that is partially self-condensed. Specific examples include hexamethoxymethylated melamine, hexabutoxymethylated melamine, tetramethoxymethylated glycoluril, and tetrabutoxymethylated glycoluril.
The commercially available compounds include Cymel 300, 301, 303, 350, 232, 235, 236, 238, 266, 267, 285, 1123, 1123-10, 1170, 370, 771, 272, 1172, 325, 327, 703, 712, 254, 253, 212, 1128, 701, 202, 207 (Japan) Made by Cytec Co., Ltd.), Nikarac MW-30M, 30, 22, 22X, Nikalac MS-21, 11, 001, Nikalac MX-002, 730, 750, 708, 706, 706, 042, 035, 45, 410, 302, 202, Nicarak SM-651, 652, 653, 551, 451, Nicarak SB-40 , The 355, the 303, the 301, the 255, the 203, the 201, NIKALAC BX-4000, the 37, the 55H, NIKALAC BL-60 (or more, manufactured by Sanwa Chemical Co., Ltd.) and the like. Preferably, one of R ¹ and R ² in Formula 1 is a hydrogen atom, that is, Cymel 325, 327, 703, 712, 254, 253, which are crosslinking components containing an imino group, 212, 1128, 701, 202, and 207 are preferable.

  A compound containing two or more cyclic ethers as a reactive group (crosslinking component II) is, for example, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl). -5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4 -Epoxy-6-methylcyclohexyl-3 ', 4'-epoxy-6'-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylene Bis (3,4-epoxycyclohexanecarboxylate), -Caprolactone-modified 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate, β-methyl-δ- Epoxycyclohexyl group-containing compounds such as valerolactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated Bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, Bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol di Glycidyl ethers, polypropylene glycol diglycidyl ethers; polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; Diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of higher aliphatic alcohols; phenol, cresol, butylphenol Or monoglycidyl ethers of polyether alcohols obtained by adding alkylene oxide to these; glycidyl esters of higher fatty acids, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′ -(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ) Ether, dicyclopentenyl bis (3-ethyl-3-oxetanylmethyl) ether, triethyleneglycol Rubis (3-ethyl-3-oxetanylmethyl) ether, tetraethyleneglycolbis (3-ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane Tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis ( 3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexa Kis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropanetetrakis (3-ethyl-3-oxetanylmethyl) ether, ethylene oxide ( EO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, propylene oxide (PO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) Ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F (3-ethyl-3 -Oxetane compounds having two or more oxetane rings in the molecule such as -oxetanylmethyl) ether.

Among these, as the crosslinking component II, 1,6-hexanediol diglycidyl ether and dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether are preferable.
The above-mentioned crosslinking component II can be used alone or in combination of two or more.

The compounding quantity of the crosslinking component in this invention is 1-100 weight part with respect to 100 weight part of resin, Preferably it is 5-70 weight part. If the blending amount is less than 1 part by weight, curing may be insufficient and the pattern may not shrink, and if it exceeds 100 parts by weight, curing may proceed excessively and the pattern may be buried.
The total amount of the resin and the crosslinking component is 0.1 to 30% by weight, preferably 1 to 20% by weight, based on the entire resin composition including the alcohol solvent described later. If the total amount of the resin and the cross-linking component is less than 0.1% by weight, the coating film may become too thin and the pattern-etched portion may be cut. If it exceeds 30% by weight, the viscosity becomes too high and the pattern is embedded in a fine pattern. There is a risk that it will not be possible.

The alcohol solvent that can be used in the present invention is a solvent that sufficiently dissolves the resin and the crosslinking component and does not dissolve the photoresist film and does not cause intermixing with the photoresist film when applied onto the photoresist film. Can be used.
Such a solvent is preferably a monohydric alcohol having 1 to 8 carbon atoms. For example, 1-propanol, isopropanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1- Butanol, 3-methyl-2-butanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3 -Methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 1-heptanol, 2- Examples include heptanol, 2-methyl-2-heptanol, 2-methyl-3-heptanol, 1-butanol, 2-butano Le, 4-methyl-2-pentanol are preferred. These alcohol solvents can be used alone or in combination of two or more.
The alcohol solvent can contain 10% by weight or less, preferably 1% by weight or less of water based on the total solvent. If it exceeds 10% by weight, the solubility of the resin having a hydroxyl group is lowered. More preferably, it is an anhydrous alcohol solvent containing no water.

The resin composition for forming a fine pattern of the present invention can be mixed with another solvent for the purpose of adjusting applicability when applied on a photoresist film. Other solvents have the effect of uniformly applying the resin composition for forming a fine pattern without eroding the photoresist film.
Other solvents include cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether Alkyl ethers of polyhydric alcohols such as diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate And alkyl ether acetates of polyhydric alcohols such as propylene glycol monomethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone , Ketones such as diacetone alcohol; ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, hydroxyacetic acid Ethyl, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, acetic acid Chill, esters such as butyl acetate, and water. Among these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, esters, and water are preferable.

  The blending ratio of the other solvent is 30% by weight or less, preferably 20% by weight or less in the total solvent. If it exceeds 30% by weight, the photoresist film may be eroded, causing problems such as intermixing with the resin composition for forming a fine pattern, and the resist pattern may be buried. In addition, when water is mixed, it is 10 weight% or less.

A surfactant may be added to the resin composition for forming a fine pattern of the present invention for the purpose of improving coating properties, antifoaming properties, leveling properties and the like.
Examples of such surfactants include BM-1000, BM-1100 (above, manufactured by BM Chemie), MegaFuck F142D, F172, F173, F183 (above, manufactured by Dainippon Ink & Chemicals, Inc.). ), FLORARD FC-135, FC-170C, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S- 141, S-145 (made by Asahi Glass Co., Ltd.), SH-28PA, -190, -193, SZ-6032, SF-8428 (above, made by Toray Dow Corning Silicone) Fluorosurfactants marketed by name can be used.
The blending amount of these surfactants is preferably 5% by weight or less with respect to 100 parts by weight of the resin.

A fine pattern is formed by the following method using the resin composition for forming a fine pattern.
(1) Formation of resist pattern An antireflection film (organic film or inorganic film) is formed on an 8-inch or 12-inch silicon wafer substrate by a conventionally known method such as spin coating. Next, a photoresist is applied by a conventionally known method such as spin coating, and prebaking (PB) is performed under conditions of, for example, about 80 ° C. to 140 ° C. and about 60 to 120 seconds. Then, exposure with ultraviolet rays such as g-line and i-line, KrF excimer laser beam, ArF excimer laser beam, X-ray, electron beam, etc., for example, post-exposure baking (PEB) under conditions of about 80 ° C to 140 ° C Then, development is performed to form a resist pattern.
(2) Formation of a fine pattern The resin composition for forming a fine pattern of the present invention is applied to a substrate on which the resist pattern is formed by a conventionally known method such as spin coating. The solvent may be volatilized only by spin coating to form a coating film. Moreover, if necessary, for example, prebaking (PB) is performed at about 80 ° C. to 110 ° C. for about 60 to 120 seconds to form a coating film of the resin composition for forming a fine pattern.
Next, the substrate on which the resist pattern is coated with the fine pattern forming resin composition is heat-treated. By the heat treatment, the acid derived from the photoresist diffuses from the interface with the photoresist into the resin composition layer for forming a fine pattern, and the resin composition for forming a fine pattern causes a crosslinking reaction. The cross-linking reaction state from the photoresist interface is determined by the material of the resin composition for fine pattern formation, the photoresist used, the baking temperature and the baking time. The heat treatment temperature and heat treatment time are usually about 90 ° C. to 160 ° C. and about 60 to 120 seconds.
Next, the coating film of the resin composition for forming a fine pattern is developed (for example, about 60 to 120 seconds) with an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) to form an uncrosslinked fine pattern. The coating film of the resin composition is dissolved and removed. Finally, a hole pattern, an elliptical pattern, a trench pattern, etc. can be made finer by washing with water.

出発原料としてｐ−ヒドロキシフェニルメタクリルアニリド（Ｐ−１−１）９２ｇ、ｐ−ｔ−ブトキシスチレン（Ｐ−１−２）４６ｇ、ｎ−ブチルメタクリレート（Ｐ−１−３）１２ｇ、およびアゾビスイソブチロニトリル１２．８ｇをイソプロパノール６００ｇに溶解し、還流条件（８２℃）にて６時間重合反応を行なった。反応容器を流水にて冷却した後、イソプロパノールを１５０ｇ加え、４５００ｇのメタノール中に攪拌しながら投入し、再沈後吸引ろ過を行なった。この再沈操作（ＩＰＡ投入〜吸引ろ過）を４回繰り返した後、５０℃にて真空乾燥した。その結果、ｐ−ヒドロキシフェニルメタクリルアニリド由来の繰り返し単位／ｔ−ブトキシスチレン由来の繰り返し単位／ｎ−ブチルメタクリレート由来の繰り返し単位＝５８／３２／１０（モル比）からなる共重合体１２１ｇ(収率８１％)を得た。繰り返し単位のモル比は、¹³Ｃ−ＮＭＲ測定により行なった。この共重合体を樹脂Ｐ−１とする。
樹脂Ｐ−１および以下の各合成例で得た各重合体のＭｗおよびＭｎの測定は、東ソー（株）社製ＧＰＣカラム（Ｇ２０００ＨＸＬ２本、Ｇ３０００ＨＸＬ１本、Ｇ４０００ＨＸＬ１本）を用い、流量１．０ミリリットル／分、溶出溶剤テトラヒドロフラン、カラム温度４０℃の分析条件で、単分散ポリスチレンを標準とするゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定した。測定の結果、樹脂Ｐ−１はＭｗ５，３００、Ｍｗ／Ｍｎ１．６であった。 The present invention will be described below with reference to examples, but the embodiments of the present invention are not limited to these examples. Hereinafter, synthetic examples of resins used in the examples will be described.
Synthesis example 1

As starting materials, 92 g of p-hydroxyphenyl methacrylanilide (P-1-1), 46 g of pt-butoxystyrene (P-1-2), 12 g of n-butyl methacrylate (P-1-3), and azobisiso 12.8 g of butyronitrile was dissolved in 600 g of isopropanol, and a polymerization reaction was performed for 6 hours under reflux conditions (82 ° C.). After cooling the reaction vessel with running water, 150 g of isopropanol was added, and the mixture was poured into 4500 g of methanol with stirring, followed by re-precipitation and suction filtration. This reprecipitation operation (IPA charging to suction filtration) was repeated four times, and then vacuum-dried at 50 ° C. As a result, 121 g (yield) of repeating unit derived from p-hydroxyphenyl methacrylanilide / repeating unit derived from t-butoxystyrene / repeating unit derived from n-butyl methacrylate = 58/32/10 (molar ratio). 81%). The molar ratio of repeating units was determined by ¹³ C-NMR measurement. This copolymer is referred to as a resin P-1.
Mw and Mn of resin P-1 and each polymer obtained in each of the following synthesis examples were measured using a GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation. Per minute, elution solvent tetrahydrofuran, and column temperature of 40 ° C. The analysis was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. As a result of the measurement, the resin P-1 was Mw 5,300 and Mw / Mn 1.6.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−２−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−２−２）、ｎ−へキシルメタクリレート（Ｐ−２−３）として、合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位／ｎ−へキシルメタクリレート由来の繰り返し単位＝５５／３４／１１（モル比）、Ｍｗ５，５００、Ｍｗ／Ｍｎ１．７からなる共重合体を得た。この共重合体を樹脂Ｐ−２とする。 Synthesis example 2

As in Synthesis Example 1, starting materials were p-hydroxymethacrylanilide (P-2-1), pt-butoxystyrene (P-2-2), and n-hexyl methacrylate (P-2-3). Repeating unit derived from p-hydroxymethacrylanilide / Repeating unit derived from pt-butoxystyrene / Repeating unit derived from n-hexyl methacrylate = 55/34/11 (molar ratio), Mw5,500, Mw / Mn1.7 A copolymer consisting of This copolymer is referred to as “resin P-2”.

出発原料をｐ−ヒドロキシアクリルアニリド（Ｐ−３−１）、ｎ−ブチルメタクリレート（Ｐ−３−２）として合成例１と同様にｐ−ヒドロキシアクリルアニリド由来の繰り返し単位／ｎ−ブチルメタクリレート由来の繰り返し単位＝７０／３０（モル比）、Ｍｗ５，７００、Ｍｗ／Ｍｎ１．５からなる共重合体を得た。この共重合体を樹脂Ｐ−３とする。 Synthesis example 3

The starting materials are p-hydroxyacrylanilide (P-3-1) and n-butyl methacrylate (P-3-2), and the same repeating unit as in Synthesis Example 1, derived from p-hydroxyacrylanilide / derived from n-butyl methacrylate. A copolymer composed of repeating units = 70/30 (molar ratio), Mw 5,700, and Mw / Mn 1.5 was obtained. This copolymer is indicated as a resin P-3.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−４−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−４−２）、オクチルアクリレート（Ｐ−４−３）として合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位／オクチルアクリレート由来の繰り返し単位＝５６／３６／８（モル比）、Ｍｗ５，９００、Ｍｗ／Ｍｎ１．９からなる共重合体を得た。この共重合体を樹脂Ｐ−４とする。 Synthesis example 4

The starting materials were p-hydroxymethacrylanilide (P-4-1), pt-butoxystyrene (P-4-2), and octyl acrylate (P-4-3) as in Synthesis Example 1 and p-hydroxymethacrylic. A copolymer comprising repeating unit derived from anilide / repeating unit derived from pt-butoxystyrene / repeating unit derived from octyl acrylate = 56/36/8 (molar ratio), Mw5,900, Mw / Mn1.9 is obtained. It was. This copolymer is indicated as a resin P-4.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−５−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−５−２）、２−エトキシエチルメタクリレート（Ｐ−５−３）として合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位／２−エトキシエチルメタクリレート由来の繰り返し単位＝５４／３４／１２（モル比）、Ｍｗ５，１００、Ｍｗ／Ｍｎ１．５からなる共重合体を得た。この共重合体を樹脂Ｐ−５とする。 Synthesis example 5

The starting materials were p-hydroxymethacrylanilide (P-5-1), pt-butoxystyrene (P-5-2), and 2-ethoxyethyl methacrylate (P-5-3). -Repeating unit derived from hydroxymethacrylanilide / repeating unit derived from pt-butoxystyrene / 2 repeating unit derived from 2-ethoxyethyl methacrylate = 54/34/12 (molar ratio), Mw5,100, Mw / Mn1.5 A copolymer was obtained. This copolymer is indicated as a resin P-5.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−６−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−６−２）、２−メトキシエチルアクリレート（Ｐ−６−３）として合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位／２−メトキシメチルアタクリレート由来の繰り返し単位＝５３／３５／１２（モル比）、Ｍｗ５，２００、Ｍｗ／Ｍｎ１．５からなる共重合体を得た。この共重合体を樹脂Ｐ−６とする。 Synthesis Example 6

The starting materials were p-hydroxymethacrylanilide (P-6-1), pt-butoxystyrene (P-6-2), and 2-methoxyethyl acrylate (P-6-3) as in Synthesis Example 1. -Repeating unit derived from hydroxymethacrylanilide / repeating unit derived from pt-butoxystyrene / 2 repeating unit derived from 2-methoxymethyl atacrylate = 53/35/12 (molar ratio), Mw5,200, Mw / Mn1. A copolymer consisting of 5 was obtained. This copolymer is indicated as a resin P-6.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−７−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−７−２）、ヒドロキシブチルアクリレート（Ｐ−７−３）として合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位／ヒドロキシブチルアクリレート由来の繰り返し単位＝５３／３６／１１（モル比）、Ｍｗ５，４００、Ｍｗ／Ｍｎ１．６からなる共重合体を得た。この共重合体を樹脂Ｐ−７とする。 Synthesis example 7

The starting materials were p-hydroxymethacrylanilide (P-7-1), pt-butoxystyrene (P-7-2), and hydroxybutyl acrylate (P-7-3) as in Synthesis Example 1, and p-hydroxy. Copolymer comprising repeating unit derived from methacrylanilide / repeating unit derived from pt-butoxystyrene / repeating unit derived from hydroxybutyl acrylate = 53/36/11 (molar ratio), Mw5,400, Mw / Mn1.6 Got. This copolymer is indicated as a resin P-7.

出発原料をｐ−ヒドロキシメタクリルアニリド（Ｐ−８−１）、ｐ−ｔ−ブトキシスチレン（Ｐ−８−２）として合成例１と同様にｐ−ヒドロキシメタクリルアニリド由来の繰り返し単位／ｐ−ｔ−ブトキシスチレン由来の繰り返し単位＝６０／４０（モル比）、Ｍｗ５，５００、Ｍｗ／Ｍｎ１．５からなる共重合体を得た。この共重合体を樹脂Ｐ−８とする。 Comparative Synthesis Example 1

The starting materials are p-hydroxymethacrylanilide (P-8-1) and pt-butoxystyrene (P-8-2), as in Synthesis Example 1, and the repeating unit derived from p-hydroxymethacrylanilide / pt- A copolymer composed of repeating units derived from butoxystyrene = 60/40 (molar ratio), Mw 5,500, and Mw / Mn 1.5 was obtained. This copolymer is indicated as a resin P-8.

Examples 1 to 9 and Comparative Examples 1 to 2
Add the above resin, cross-linking component, alcohol solvent and other additives at the ratio shown in Table 1, stir for 3 hours using a stirring blade, and then filter using a filter with a pore diameter of 30 nm for fine pattern formation. A resin composition was obtained.
The crosslinking components and alcohol solvents used in the examples and comparative examples are shown below.
Cross-linking component C-1: Nicalak MX-750 (manufactured by Nippon Carbide, trade name)
C-2: Dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether alcohol solvent S-1: 1-butanol S-2: 4-methyl-2-pentanol

In order to evaluate the obtained resin composition for forming a fine pattern, an evaluation substrate with a resist pattern was prepared by the following method.
After forming a coating film with a film thickness of 77 nm (PB205 ° C., 60 seconds) on a 8-inch silicon wafer by spin coating a lower antireflection film ARC29A (Brewer Science Co., Ltd.) with CLEAN TRACK ACT8 (Tokyo Electron Ltd.), Patterning of JSR ArF AR1244J (manufactured by JSR Corporation, alicyclic radiation-sensitive resin composition) is performed. AR1244J formed a coating film with a film thickness of 210 nm by spin coating, PB (130 ° C., 90 seconds) and cooling (23 ° C., 30 seconds) with the CLEAN TRACK ACT 8, and ArF projection exposure apparatus S306C (Nikon Corporation) ), NA: 0.78, Sigma: 0.85, 2/3 Ann (exposure amount 30 mJ / cm ² ), and PEB (130 ° C., 90 seconds) on the CLEAN TRACK ACT8 hot plate. ) After cooling (23 ° C., 30 seconds), 2.38 wt% TMAH aqueous solution is used as a developing solution with a development nozzle LD paddle development (60 seconds), rinsed with ultrapure water, and then shaken off at 4000 rpm for 15 seconds. Was spin-dried to obtain an evaluation substrate. The substrate obtained in this step is referred to as an evaluation substrate A. A plurality of evaluation substrates A prepared under the same conditions were prepared.
The obtained substrate for evaluation corresponds to a 100 nm diameter hole pattern and a 100 nm space mask pattern (bias +30 nm / 130 nm diameter pattern / 70 nm space on the mask) with a scanning electron microscope (S-9360 manufactured by Hitachi Keiki Co., Ltd.). The hole diameter of the resist pattern was measured.

In the examples shown in Table 1 for the evaluation substrate with a resist pattern, the resin composition for forming a fine pattern was evaluated by the following method. Each evaluation result is shown in Table 2.
(1) Evaluation of shrinkage dimension and baking temperature dependency On the above-mentioned evaluation substrate A, a resin composition for forming a fine pattern described in Table 1 was applied by CLEAN TRACK ACT8 to a film thickness of 150 nm by spin coating. In order to react the pattern and the resin composition for forming a fine pattern, baking was performed under the shrinkage rate evaluation baking conditions shown in Table 1. Then, after cooling with a CLEAN TRACK ACT8 at 23 ° C. for 30 seconds, using a development cup, paddle development with a 2.38 wt% TMAH aqueous solution as a developer using an LD nozzle (60 seconds), rinsing with ultrapure water, Subsequently, it spin-dried by shaking off at 4000 rpm for 15 seconds. The substrate obtained in this step is referred to as an evaluation substrate B. Shrinkage measurement of pattern dimensions corresponds to a 100 nm diameter hole pattern, 100 nm space mask pattern (bias +30 nm / 130 nm diameter pattern / 70 nm space on the mask) with a scanning electron microscope (S-9360 manufactured by Hitachi Keiki Co., Ltd.) The pattern to be observed was observed, and the hole diameter of the pattern was measured.
Shrinkage dimension (nm) = φ1-φ2
φ1: Resist pattern hole diameter of evaluation substrate A (nm)
φ2: resist pattern hole diameter of evaluation substrate B (nm)
As the judgment of shrinkage, “◯” is shown when shrinkage is confirmed and the shrinkage dimension is 20 nm or more, and “X” is given when shrinkage is not confirmed or the pattern is collapsed or the shrinkage dimension is less than 20 nm. .
(2) Confirmation and evaluation of insoluble matter The substrate B for evaluation was scanned with a scanning electron microscope (S-4800, manufactured by Hitachi Sokki Co., Ltd.) with a 100 nm diameter hole pattern, a 100 nm space mask pattern (bias +30 nm / 130 nm diameter pattern on the mask). The cross section of the pattern corresponding to (/ 70 nm space) was observed. When there was no insoluble matter at the bottom of the opening, “◯” was indicated, and when insoluble matter was observed, “X” was assigned.
(3) Shape evaluation after pattern shrinkage In evaluation substrate A and evaluation substrate B, a scanning electron microscope (S-4800, manufactured by Hitachi Sokki Co., Ltd.) uses a 100 nm diameter hole pattern, a 100 nm space mask pattern (bias +30 nm / The cross section of the pattern corresponding to 130 nm pattern / 70 nm space on the mask and existing at the same position is observed. The cross-sectional shape is shown in FIG. The resist film thickness t in the evaluation substrate A (FIG. 1A) is set to 100, and the deteriorated portion t is changed into a pattern on the evaluation substrate B only in a portion from the substrate 1 where the resist film thickness tt ′ exceeds 80. Those where 'was recognized as good (FIG. 1 (b)), and others were bad (see FIG. 1). The evaluation results are shown in Table 2.

  The resin composition for forming a fine pattern according to the present invention can effectively and accurately miniaturize the pattern gap between resist patterns, and can form a pattern that exceeds the wavelength limit in a favorable and economical manner. It can be used very suitably in the field of microfabrication represented by the manufacture of integrated circuit elements, which are expected to progress.

Cross section of hole pattern

Explanation of symbols

1 Substrate 2 Hole pattern

Claims (7)

A resin composition for forming a fine pattern for making a resist pattern fine, comprising a resin, a crosslinking component for crosslinking the resin, and a solvent,
A resin composition for forming a fine pattern, wherein the resin contains a repeating unit (I) represented by the following formula (1).

(In the formula (1), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R ² represents a hydrogen atom, a linear alkoxyl group, or a hydroxyl group, and R ² represents a hydrogen atom or a hydroxyl group. , N is an integer of 2 to 8, and when R ² is a linear alkoxyl group, n is an integer of 2 to 7, including the carbon number of the linear alkoxyl group, — (CH ₂ ) n-R ² group has 2 to 8 carbon atoms.)   2. The resin composition for forming a fine pattern according to claim 1, wherein the repeating unit (I) is contained in an amount of 3 to 30 mol% with respect to all monomers constituting the resin.   The resin composition for forming a fine pattern according to claim 1, wherein the resin contains a repeating unit (II) containing at least one hydroxyl group selected from hydroxyl groups derived from phenols and carboxylic acids. The said resin contains the repeating unit (III) represented by following formula (2), The fine pattern formation resin composition of Claim 1, 2 or 3 characterized by the above-mentioned.

(In Formula (2), R ³ represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxyl group having 1 to 8 carbon atoms.) The cross-linking component is at least one compound selected from a compound containing a group represented by the following formula (3) and a compound containing two or more cyclic ethers as a reactive group. 1. The resin composition for forming a fine pattern according to 1.

(In the formula (3), R ⁴ and R ⁵ are each represented by a hydrogen atom or the following formula (4), and at least one of R ⁴ and R ⁵ is represented by the following formula (4);

In Formula (4), R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 1 to 6 carbon atoms, or 2 to 10 carbon atoms in which R ⁶ and R ⁷ are linked to each other. R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )   2. The resin composition for forming a fine pattern according to claim 1, wherein the solvent is a monohydric alcohol having 1 to 8 carbon atoms.   A pattern forming step of forming a resist pattern on the substrate; a coating step of forming a coating of the resin composition for forming a fine pattern on the resist pattern; a step of heat-treating the substrate after the coating step; The method for forming a fine pattern comprising the steps of removing water and washing with water, wherein the resin composition for forming a fine pattern is the resin composition for forming a fine pattern according to claim 1 .

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