JP2008163243A - Method for synthesizing star polymer - Google Patents

Abstract

A method for synthesizing a star polymer in an atmosphere containing oxygen is provided.
When synthesizing a star polymer through living radical polymerization of a monomer, divinyl containing an aromatic divinyl-based hydrocarbon during or after living radical polymerization in an oxygen-containing atmosphere using 9-BBN as an initiator. A monomer was added. Thereby, while simplifying the synthesis process of a star polymer in industrial mass production, the cost concerning synthesis can be reduced.
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Description

  The present invention relates to a method for synthesizing a star polymer.

  In recent years, optical lithography, which is regarded as promising as a microfabrication technology, has advanced design rule miniaturization due to the shortening of the wavelength of the light source, thereby realizing high integration of VLSI. EUV lithography is considered promising for design rules of 45 nm or less.

  For the resist composition, development of a base polymer having a chemical structure transparent to each light source is in progress. For example, in KrF excimer laser light (wavelength 248 nm), a polymer having a novolac polyphenol as a basic skeleton (see, for example, Patent Document 1 below), and in ArF excimer laser light (wavelength 193 nm), poly (meth) acrylate (for example, , Or refer to Patent Document 2 below), or F2 excimer laser light (wavelength 157 nm), respectively, a resist composition containing a polymer into which a fluorine atom (perfluoro structure) is introduced (for example, see Patent Document 3 below) is proposed. These polymers are based on a linear structure.

  However, when these linear polymers are applied to the formation of ultrafine patterns of 45 nm or less, the unevenness of the pattern side wall with the line edge roughness as an index has been a problem. Franco Cerrina, Vac. Sci. Tech. In B, 19, 2890 (2001), conventional resists mainly composed of PMMA (polymethyl methacrylate) and PHS (polyhydroxystyrene) are exposed to an electron beam or extreme ultraviolet light (EUV: 13.5 nm). It has been pointed out that controlling the surface smoothness at the nano level becomes a problem in order to form ultrafine patterns.

  Toru Yamaguchi, Jpn. J. et al. Appl. Phys. , 38, 7114 (1999), the unevenness of the pattern side wall is attributed to a polymer aggregate (cluster) constituting the resist. It is said that the decrease in line edge roughness due to clusters can be reduced by using a low molecular weight monodisperse polymer (see, for example, Patent Document 4 below). However, when a low molecular weight polymer is used, the Tg of the polymer decreases. However, since baking with heat becomes difficult, it lacks practicality.

  On the other hand, a branched polymer is known as an example in which line edge roughness is improved as compared with a linear molecule (Alexander R. Trimble, Processeds of SPIE, 3999, 1198, (2000)). However, in terms of adhesion to the substrate and sensitivity, those satisfying the requirements associated with miniaturization of design rules have not been achieved.

  From such a viewpoint, attempts have been made in recent years to use hyperbranched polymers as resist materials. According to the pamphlet of International Publication No. 2005/061566, a hyperbranch having an advanced branch (branch) structure as a core and an acid group (for example, carboxylic acid) and an acid-decomposable group (for example, carboxylic acid ester) at the molecular end. The polymer has less entanglement between the molecules found in the linear polymer, and the swelling by the solvent is smaller than the molecular structure that crosslinks the main chain, and as a result, the large molecular aggregate that causes the surface roughness on the pattern side wall. It has been reported that formation is suppressed.

  In addition, the hyperbranched polymer usually takes a spherical form. However, when an acid-decomposable group is present on the spherical polymer surface, in photolithography, a decomposition reaction occurs due to the action of an acid generated from the photoacid generator at the exposed portion, and hydrophilicity occurs. As a result of the formation of groups, it has been reported that a spherical micelle-like structure in which a large number of hydrophilic groups exist on the outer periphery of the polymer molecule can be taken. As a result, it was reported that the polymer was efficiently dissolved in an alkaline aqueous solution and removed together with the alkaline solution, so that a fine pattern could be formed and it could be suitably used as a base resin for a resist material. Has been. Furthermore, it has been clarified that the alkali solubility after exposure, that is, the improvement in sensitivity, can be achieved by coexistence at a certain ratio of the carboxylic acid ester group and the carboxylic acid group which are acid-decomposable groups. ing.

Japanese Patent Laid-Open No. 2004-231858 JP 2004-359929 A JP 2005-91428 A JP-A-6-266099

  As an example of synthesizing a resist polymer containing an acid-decomposable group and an acid group on the surface of the hyperbranched polymer, an example using atom transfer radical polymerization is known (see, for example, WO 2005/061566). In atom transfer radical polymerization (ATRP method), a reversible transfer reaction of an atom or group from a dormant species (RX) to a transition metal catalyst, thereby a radical that initiates polymerization, and an oxidation state advance by one. The polymerization is preferably carried out in a strictly degassed environment based on the reaction in which the metal halide is formed.

  Conventionally, in the radical polymerization, not limited to the ATRP method, it is known that oxygen in the air inhibits the reaction such as controlling the reaction as a biradical, and the reaction is not performed in an air atmosphere. However, the inert gas replacement step is not desirable because it not only complicates the process but also disadvantages in terms of cost, assuming industrial use.

  This invention is made | formed in view of the said situation, and it aims at providing the synthesis | combining method of the star polymer which synthesize | combines a star polymer in oxygen presence atmosphere.

  In order to solve the above-described problems and achieve the object, a method for synthesizing a star polymer according to the present invention is a method for synthesizing a star polymer through a living radical polymerization of a monomer, which comprises an acid-decomposable group. The arm part is synthesized by simultaneously polymerizing the monomer having the acid group and the monomer having an acid group, and adding a divinyl monomer containing an aromatic divinyl hydrocarbon to the arm part during or after the synthesis of the arm part. It is characterized by doing.

  In the synthesis method of the star polymer synthesis method according to the present invention, the copolymer is 9-borabicyclo [3.3.1] nonane (hereinafter referred to as 9-BBN) as a polymerization initiator in an oxygen-existing atmosphere. It is characterized by being synthesized by living radical polymerization.

  According to the present invention, it is possible to provide a star polymer synthesis method for synthesizing a star polymer in an oxygen-existing atmosphere.

  The method for synthesizing a star polymer according to the present invention is a method for synthesizing a star polymer by synthesizing a star polymer through living radical polymerization of a monomer in an oxygen-containing atmosphere using 9-BBN as an initiator. A divinyl monomer containing an aromatic divinyl hydrocarbon is added during or after polymerization of the polymer synthesized by the above process.

  The star polymer according to the present invention is characterized in that it is synthesized according to the above-described star polymer synthesis method.

  Moreover, the resist composition concerning this invention is characterized by including said star polymer.

  A semiconductor integrated circuit according to the present invention is characterized in that a pattern is formed by the resist composition described above.

  According to the present invention, it is possible to obtain a fine semiconductor integrated circuit having stable performance and corresponding to an electron beam, deep ultraviolet (DUV), and extreme ultraviolet (EUV) light source.

  A method for manufacturing a semiconductor integrated circuit according to the present invention includes a step of forming a pattern using the resist composition.

  According to the present invention, it is possible to manufacture a fine semiconductor integrated circuit having stable performance and corresponding to an electron beam, deep ultraviolet (DUV), and extreme ultraviolet (EUV) light source.

  Exemplary embodiments of a method for synthesizing a star polymer according to the present invention will be described below in detail with reference to the accompanying drawings.

(Substances used for star polymer synthesis)
First, a substance used for synthesizing a star polymer (hereinafter simply referred to as “star polymer”) synthesized using the method for synthesizing a star polymer according to the embodiment will be described. In the synthesis of the star polymer, a monomer, 9-BBN, a solvent, and a coordinating solvent are used.

(monomer)
First, the monomer used for the synthesis of the star polymer will be described. When synthesizing a star polymer, monomers used for synthesizing a star polymer are roughly classified into a monomer constituting an arm part and a monomer constituting a core part.

<Monomer composing arm part>
Next, among the monomers used for synthesizing the star polymer, the monomers constituting the arm part will be described. The shell portion of the star polymer constitutes the end of the star polymer molecule. The shell portion of the star polymer includes at least one of repeating units represented by the following formulas (II) and (III).

  The repeating units represented by the following formulas (II) and (III) generate an acid by the action of an organic acid such as acetic acid, maleic acid or benzoic acid or an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, preferably by light energy. It contains an acid-decomposable group that decomposes by the action of a photoacid generator. The ratio of the acid-decomposable group to the acid group in the shell part is preferably 95/5 to 5/95, although the optimum value varies depending on the ratio of the other monomer constituting the star polymer. The acid-decomposable group is preferably decomposed into a hydrophilic group.

R ¹ in the above formula (II) and R ⁴ in the above formula (III) represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Of these, R ¹ in the above formula (II) and R ⁴ in the above formula (III) are preferably a hydrogen atom and a methyl group. As R ¹ in the above formula (II) and R ⁴ in the above formula (III), a hydrogen atom is more preferable.

R ² in the above formula (II) represents a hydrogen atom, an alkyl group, or an aryl group. The alkyl group for R ² in the above formula (II) preferably has, for example, 1 to 30 carbon atoms. The more preferable carbon number of the alkyl group in R < ² > in said formula (II) is 1-20. The more preferable carbon number of the alkyl group in R ² in the above formula (II) is 1-10. The alkyl group has a linear, branched or cyclic structure. Specifically, examples of the alkyl group for R ² in the above formula (II) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, and a cyclohexyl group. It is done.

The aryl group for R ² in the above formula (II) preferably has, for example, 6 to 30 carbon atoms. The more preferable carbon number of the aryl group in R ² in the above formula (II) is 6-20. The more preferable carbon number of the aryl group in R ² in the above formula (II) is 6-10. Specifically, examples of the aryl group in R ² in the above formula (II) include a phenyl group, a 4-methylphenyl group, and a naphthyl group. Among these, a hydrogen atom, a methyl group, an ethyl group, a phenyl group, etc. are mentioned. As R ² in the above formula (II), one of the most preferred groups is a hydrogen atom.

R ³ in the above formula (II) and R ⁵ in the above formula (III) represent a hydrogen atom, an alkyl group, a trialkylsilyl group, an oxoalkyl group, or a group represented by the following formula (i). . The alkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) preferably has 1 to 40 carbon atoms. The carbon number of the alkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) is preferably 1-30.

The more preferable carbon number of the alkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) is 1-20. The alkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) has a linear, branched or cyclic structure. R ³ in the above formula (II) and R ⁵ in the above formula (III) are more preferably a branched alkyl group having 1 to 20 carbon atoms.

The preferable carbon number of each alkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) is 1-6, and more preferable carbon number is 1-4. The carbon number of the alkyl group of the oxoalkyl group in R ³ in the above formula (II) and R ⁵ in the above formula (III) is 4-20, and more preferably 4-10.

R ⁶ in the above formula (i) represents a hydrogen atom or an alkyl group. The alkyl group in R ⁶ of the group represented by the above formula (i) has a linear, branched, or cyclic structure. The number of carbon atoms of the alkyl group in R ⁶ of the group represented by the above formula (i) is preferably 1-10. The more preferable carbon number of the alkyl group in R < ⁶ > of the group represented by the said formula (i) is 1-8, and a more preferable carbon number is 1-6.

R ⁷ and R ⁸ in the above formula (i) are a hydrogen atom or an alkyl group. The hydrogen atom or alkyl group in R ⁷ and R ⁸ in the above formula (i) may be independent of each other or may form a ring together. The alkyl group in R ⁷ and R ⁸ in the above formula (i) has a linear, branched or cyclic structure. It is preferable that carbon number of the alkyl group in R < ⁷ > and R < ⁸ > in the said formula (i) is 1-10. The more preferable carbon number of the alkyl group in R ⁷ and R ⁸ in the above formula (i) is 1-8. The more preferable carbon number of the alkyl group in R ⁷ and R ⁸ in the above formula (i) is 1-6. As R < ⁷ > and R < ⁸ > in said formula (i), a C1-C20 branched alkyl group is preferable.

  Examples of the group represented by the above formula (i) include 1-methoxyethyl group, 1-ethoxyethyl group, 1-n-propoxyethyl group, 1-isopropoxyethyl group, 1-n-butoxyethyl group, 1-iso Butoxyethyl group, 1-sec-butoxyethyl group, 1-tert-butoxyethyl group, 1-tert-amyloxyethyl group, 1-ethoxy-n-propyl group, 1-cyclohexyloxyethyl group, methoxypropyl group, ethoxy Linear or branched acetal groups such as propyl group, 1-methoxy-1-methyl-ethyl group, 1-ethoxy-1-methyl-ethyl group; cyclic acetal groups such as tetrahydrofuranyl group, tetrahydropyranyl group, etc. Is mentioned. As the group represented by the above formula (i), among the above-mentioned groups, an ethoxyethyl group, a butoxyethyl group, an ethoxypropyl group, and a tetrahydropyranyl group are particularly preferable.

In R ³ in the above formula (II) and R ⁵ in the above formula (III), as the linear, branched or cyclic alkyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, tert-butyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, triethylcarbyl group, 1-ethylnorbornyl group, 1-methylcyclohexyl group, adamantyl group, 2- (2-methyl) adamantyl group, tert-amyl group Etc. Of these, a tert-butyl group is particularly preferred.

In R ³ in the above formula (II) and R ⁵ in the above formula (III), as the trialkylsilyl group, the carbon number of each alkyl group such as trimethylsilyl group, triethylsilyl group, dimethyl-tert-butylsilyl group, etc. 1-6 are mentioned. Examples of the oxoalkyl group include a 3-oxocyclohexyl group.

  As the monomer that gives the repeating unit represented by the above formula (II), vinyl benzoic acid, tert-butyl vinyl benzoate, 2-methylbutyl vinyl benzoate, 2-methylpentyl vinyl benzoate, 2-ethylbutyl vinyl benzoate, vinyl 3-methylpentyl benzoate, 2-methylhexyl vinylbenzoate, 3-methylhexyl vinylbenzoate, triethylcarbyl vinylbenzoate, 1-methyl-1-cyclopentyl vinylbenzoate, 1-ethyl-1-vinylbenzoate Cyclopentyl, 1-methyl-1-cyclohexyl vinylbenzoate, 1-ethyl-1-cyclohexyl vinylbenzoate, 1-methylnorbornyl vinylbenzoate, 1-ethylnorbornyl vinylbenzoate, 2-methyl-2 vinylbenzoate -Adamantyl, vinylbenzoic acid 2-d Lu-2-adamantyl, 3-hydroxy-1-adamantyl vinyl benzoate, tetrahydrofuranyl vinyl benzoate, tetrahydropyranyl vinyl benzoate, 1-methoxyethyl vinyl benzoate, 1-ethoxyethyl vinyl benzoate, vinyl benzoic acid 1 -N-propoxyethyl, 1-isopropoxyethyl vinylbenzoate, n-butoxyethyl vinylbenzoate, 1-isobutoxyethyl vinylbenzoate, 1-sec-butoxyethyl vinylbenzoate, 1-tert-butoxy vinylbenzoate Ethyl, 1-tert-amyloxyethyl vinyl benzoate, 1-ethoxy-n-propyl vinyl benzoate, 1-cyclohexyloxyethyl vinyl benzoate, methoxypropyl vinyl benzoate, ethoxypropyl vinyl benzoate, 1-vinyl benzoate 1- Meto Xyl-1-methyl-ethyl, 1-ethoxy-1-methyl-ethyl vinylbenzoate, trimethylsilyl vinylbenzoate, triethylsilyl vinylbenzoate, dimethyl-tert-butylsilyl vinylbenzoate, α- (4-vinylbenzoyl) oxy -Γ-butyrolactone, β- (4-vinylbenzoyl) oxy-γ-butyrolactone, γ- (4-vinylbenzoyl) oxy-γ-butyrolactone, α-methyl-α- (4-vinylbenzoyl) oxy-γ-butyrolactone , Β-methyl-β- (4-vinylbenzoyl) oxy-γ-butyrolactone, γ-methyl-γ- (4-vinylbenzoyl) oxy-γ-butyrolactone, α-ethyl-α- (4-vinylbenzoyl) oxy -Γ-butyrolactone, β-ethyl-β- (4-vinylbenzoyl) oxy-γ-butyl Lolactone, γ-ethyl-γ- (4-vinylbenzoyl) oxy-γ-butyrolactone, α- (4-vinylbenzoyl) oxy-δ-valerolactone, β- (4-vinylbenzoyl) oxy-δ-valerolactone, γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ- (4-vinylbenzoyl) oxy-δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β -Methyl-β- (4-vinylbenzoyl) oxy-δ-valerolactone, γ-methyl-γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ-methyl-δ- (4-vinylbenzoyl) oxy -Δ-valerolactone, α-ethyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-ethyl-β- (4-vinylbenzoyl) Oxy-δ-valerolactone, γ-ethyl-γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ-ethyl-δ- (4-vinylbenzoyl) oxy-δ-valerolactone, vinylbenzoic acid 1- Methylcyclohexyl, adamantyl vinylbenzoate, 2- (2-methyl) adamantyl vinylbenzoate, chloroethyl vinylbenzoate, 2-hydroxyethyl vinylbenzoate, 2,2-dimethylhydroxypropyl vinylbenzoate, 5-hydroxyvinylbenzoate Examples include pentyl, trimethylolpropane vinylbenzoate, glycidyl vinylbenzoate, benzyl vinylbenzoate, phenyl vinylbenzoate, and naphthyl vinylbenzoate. Of these, a copolymer of 4-vinylbenzoic acid and tert-butyl 4-vinylbenzoate is preferable.

  Monomers that give the repeating unit represented by the above formula (III) include acrylic acid, tert-butyl acrylate, 2-methylbutyl acrylate, 2-methylpentyl acrylate, 2-ethylbutyl acrylate, and 3-methylpentyl acrylate. 2-methylhexyl acrylate, 3-methylhexyl acrylate, triethylcarbyl acrylate, 1-methyl-1-cyclopentyl acrylate, 1-ethyl-1-cyclopentyl acrylate, 1-methyl-1-cyclohexyl acrylate 1-ethyl-1-cyclohexyl acrylate, 1-methylnorbornyl acrylate, 1-ethylnorbornyl acrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, acrylic acid 3 -Hydroxy-1-adamantyl, Tetrahydrofuranyl acrylate, tetrahydropyranyl acrylate, 1-methoxyethyl acrylate, 1-ethoxyethyl acrylate, 1-n-propoxyethyl acrylate, 1-isopropoxyethyl acrylate, n-butoxyethyl acrylate, acrylic 1-isobutoxyethyl acid, 1-sec-butoxyethyl acrylate, 1-tert-butoxyethyl acrylate, 1-tert-amyloxyethyl acrylate, 1-ethoxy-n-propyl acrylate, 1-cyclohexyl acrylate Siloxyethyl, methoxypropyl acrylate, ethoxypropyl acrylate, 1-methoxy-1-methyl-ethyl acrylate, 1-ethoxy-1-methyl-ethyl acrylate, trimethylsilyl acrylate, triethylsilyl acrylate, acrylic Dimethyl-tert-butylsilyl, α- (acryloyl) oxy-γ-butyrolactone, β- (acryloyl) oxy-γ-butyrolactone, γ- (acryloyl) oxy-γ-butyrolactone, α-methyl-α- (acryloyl) oxy- γ-butyrolactone, β-methyl-β- (acryloyl) oxy-γ-butyrolactone, γ-methyl-γ- (acryloyl) oxy-γ-butyrolactone, α-ethyl-α- (acryloyl) oxy-γ-butyrolactone, β -Ethyl-β- (acryloyl) oxy-γ-butyrolactone, γ-ethyl-γ- (acryloyl) oxy-γ-butyrolactone, α- (acryloyl) oxy-δ-valerolactone, β- (acryloyl) oxy-δ- Valerolactone, γ- (Acroyl) oxy-δ-valerolactone, δ- (Acroyl) oxy-δ Valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-methyl-β- (acroyl) oxy-δ-valerolactone, γ-methyl-γ- (acroyl) oxy-δ -Valerolactone, δ-methyl-δ- (acryloyl) oxy-δ-valerolactone, α-ethyl-α- (acryloyl) oxy-δ-valerolactone, β-ethyl-β- (acryloyl) oxy-δ-valero Lactone, γ-ethyl-γ- (acryloyl) oxy-δ-valerolactone, δ-ethyl-δ- (acryloyl) oxy-δ-valerolactone, 1-methylcyclohexyl acrylate, adamantyl acrylate, 2- (acrylate) 2-methyl) adamantyl, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2,2-dimethylhydroxyacrylate Cypropyl, 5-hydroxypentyl acrylate, trimethylolpropane acrylate, glycidyl acrylate, benzyl acrylate, phenyl acrylate, naphthyl acrylate, methacrylic acid, tert-butyl methacrylate, 2-methylbutyl methacrylate, 2-methacrylic acid 2- Methylpentyl, 2-ethylbutyl methacrylate, 3-methylpentyl methacrylate, 2-methylhexyl methacrylate, 3-methylhexyl methacrylate, triethylcarbyl methacrylate, 1-methyl-1-cyclopentyl methacrylate, 1-methacrylic acid 1- Ethyl-1-cyclopentyl, 1-methyl-1-cyclohexyl methacrylate, 1-ethyl-1-cyclohexyl methacrylate, 1-methylnorbornyl methacrylate, 1-ethylnorbornyl methacrylate 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, tetrahydrofuranyl methacrylate, tetrahydropyranyl methacrylate, 1-methoxyethyl methacrylate, methacrylic acid 1-ethoxyethyl acid, 1-n-propoxyethyl methacrylate, 1-isopropoxyethyl methacrylate, n-butoxyethyl methacrylate, 1-isobutoxyethyl methacrylate, 1-sec-butoxyethyl methacrylate, methacrylic acid 1 -Tert-butoxyethyl, 1-tert-amyloxyethyl methacrylate, 1-ethoxy-n-propyl methacrylate, 1-cyclohexyloxyethyl methacrylate, methoxypropyl methacrylate, ethoxy methacrylate Propyl, 1-methoxy-1-methyl-ethyl methacrylate, 1-ethoxy-1-methyl-ethyl methacrylate, trimethylsilyl methacrylate, triethylsilyl methacrylate, dimethyl-tert-butylsilyl methacrylate, α- (methacryloyl) oxy- γ-butyrolactone, β- (methacryloyl) oxy-γ-butyrolactone, γ- (methacryloyl) oxy-γ-butyrolactone, α-methyl-α- (methacryloyl) oxy-γ-butyrolactone, β-methyl-β- (methacryloyl) Oxy-γ-butyrolactone, γ-methyl-γ- (methacryloyl) oxy-γ-butyrolactone, α-ethyl-α- (methacryloyl) oxy-γ-butyrolactone, β-ethyl-β- (methacryloyl) oxy-γ-butyrolactone , Γ-ethyl-γ- (metacroy ) Oxy-γ-butyrolactone, α- (methacryloyl) oxy-δ-valerolactone, β- (methacryloyl) oxy-δ-valerolactone, γ- (methacryloyl) oxy-δ-valerolactone, δ- (methacryloyl) oxy- δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-methyl-β- (methacloyl) oxy-δ-valerolactone, γ-methyl-γ- (methacloyl) oxy -Δ-valerolactone, δ-methyl-δ- (methacryloyl) oxy-δ-valerolactone, α-ethyl-α- (methacryloyl) oxy-δ-valerolactone, β-ethyl-β- (methacryloyl) oxy-δ -Valerolactone, γ-ethyl-γ- (methacloyl) oxy-δ-valerolactone, δ-ethyl-δ- (methacloyl) oxy -Δ-valerolactone, 1-methylcyclohexyl methacrylate, adamantyl methacrylate, 2- (2-methyl) adamantyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2-dimethylhydroxypropyl methacrylate, methacryl Examples include acid 5-hydroxypentyl, trimethylolpropane methacrylate, glycidyl methacrylate, benzyl methacrylate, phenyl methacrylate, naphthyl methacrylate, and the like. Of these, a copolymer of acrylic acid and tert-butyl acrylate is preferred.

  In addition, as a monomer which comprises an arm part, the copolymer of at least one of 4-vinyl benzoic acid or acrylic acid, and at least one of tert-butyl 4-vinyl benzoate or tert-butyl acrylate is also preferable. The monomer constituting the arm portion may be a monomer other than the monomer that gives the repeating unit represented by the above formula (II) and the above formula (III) as long as it has a structure having a radical polymerizable unsaturated bond. .

  Examples of the copolymerizable monomer that can be used include compounds having a radical polymerizable unsaturated bond selected from styrenes, allyl compounds, vinyl ethers, vinyl esters, crotonic acid esters and the like other than those described above. It is done.

  Specific examples of styrenes listed as copolymerizable monomers that can be used as monomers constituting the arm portion include styrene, tert-butoxystyrene, α-methyl-tert-butoxystyrene, 4- ( 1-methoxyethoxy) styrene, 4- (1-ethoxyethoxy) styrene, tetrahydropyranyloxystyrene, adamantyloxystyrene, 4- (2-methyl-2-adamantyloxy) styrene, 4- (1-methylcyclohexyloxy) styrene , Trimethylsilyloxystyrene, dimethyl-tert-butylsilyloxystyrene, tetrahydropyranyloxystyrene, benzylstyrene, trifluoromethylstyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, trichloro Styrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene, And vinyl naphthalene.

  Specific examples of allyl esters listed as copolymerizable monomers that can be used as monomers constituting the arm portion include, for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate , Allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, allyloxyethanol, and the like.

  Specific examples of the vinyl ethers listed as copolymerizable monomers that can be used as the monomer constituting the arm portion include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, and ethoxyethyl vinyl ether. , Chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl Vinyl ether, vinyl phenyl ether, vinyl Tolyl ether, vinyl chlorophenyl ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether, and the like.

  Specific examples of the vinyl esters that can be used as the monomer constituting the arm portion include vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl, and the like. Valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinylphenylacetate, vinylacetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate, etc. Can be mentioned.

  Specific examples of the crotonic acid esters that can be used as the monomer constituting the arm portion include, for example, butyl crotonate, hexyl crotonate, glycerin monocrotonate, dimethyl itaconate, Examples include diethyl itaconate, dibutyl itaconate, dimethyl maleate, dibutyl fumarate, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilonitrile and the like.

  Specific examples of the copolymerizable monomer that can be used as the monomer constituting the arm part include the following formulas (IV) to (XIII).

  Among the above-described formulas (IV) to (XIII), styrenes and crotonic acid esters are preferable as the copolymerizable monomer that can be used as the monomer constituting the arm portion. Among the above-mentioned formulas (IV) to (XIII), copolymer monomers that can be used as monomers constituting the arm are styrene, benzylstyrene, chlorostyrene, vinylnaphthalene, butyl crotonate, hexyl crotonate, and maleic anhydride. Acid is preferred.

  In the star polymer, the monomer giving the repeating unit represented by at least one of the above formula (II) or the above formula (III) is 10 to 90 at the time of charging relative to the total amount of monomers used for the synthesis of the star polymer. It is preferably contained in the range of mol%. It is more preferable that the monomer giving the above-mentioned repeating unit is contained in the range of 20 to 90 mol% at the time of charging with respect to the charging amount of the whole monomer used for the synthesis of the star polymer.

  It is more preferable that the monomer giving the above-mentioned repeating unit is contained in the polymer in the range of 30 to 90 mol% at the time of charging with respect to the charging amount of the whole monomer used for the synthesis of the star polymer. In particular, the repeating unit represented by the above formula (II) or the above formula (III) in the arm portion is 50 to 100 mol% at the time of charging, preferably with respect to the total amount of monomers used for the synthesis of the star polymer. It is preferable that it is contained in the range of 80 to 100 mol%.

  Lithography using a resist composition containing the star polymer when the monomer giving the repeating unit is within the above-mentioned range at the time of preparation with respect to the preparation amount of the whole monomer used for the synthesis of the star polymer. In this development step, the exposed portion is preferably dissolved and removed in the alkaline solution efficiently.

  When the star polymer arm part is a copolymer of a monomer that gives the repeating unit represented by the above formula (II) or the above formula (III) and another monomer, the above formula in all monomers forming the arm part The amount of (II) or at least one of the above formula (III) is preferably 30 to 90 mol%, more preferably 50 to 70 mol%. When the amount of at least one of the above formula (II) or the above formula (III) in all the monomers forming the arm portion is within the above-mentioned range, the etching resistance is not inhibited without inhibiting the effective alkali solubility of the exposed portion. It is preferable because functions such as wettability and glass transition temperature are increased.

  In addition, the amount of the repeating unit represented by at least one of the above formula (II) or the above formula (III) in the arm part and the other repeating unit is a charging ratio of the molar ratio at the time of introducing the arm part depending on the purpose. Can be adjusted.

<Monomer constituting the core>
Below, the monomer which can be used for formation of the core part of a star polymer is demonstrated. The core portion of the star polymer can be formed using monomers corresponding to the following (1) to (12). The monomer has two or more functional groups involved in the polymerization reaction in its molecular structure.

(1) Aromatic vinyl hydrocarbons (2) Vinyl hydrocarbons (3) Ester group-containing vinyl monomers (4) Sulfone group-containing vinyl monomers, vinyl sulfate monoesters and their salts ( 5) Phosphoric group-containing vinyl monomers (6) Hydroxyl group-containing vinyl monomers (7) Nitrogen-containing vinyl monomers (8) Halogen element-containing vinyl monomers (9) Carboxyl group-containing vinyl monomers Monomer and its salt (10) Silicon-containing vinyl monomer (11) Monomer included in the existing patents (12) Vinyl monomer in which an initiator site is introduced into the vinyl monomer structure

  Specific examples of the aromatic vinyl hydrocarbon in the above (1) include, for example, o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, divinyltoluene, 1,4-diisopropenylbenzene, tri And vinyl benzene. Examples of the vinyl hydrocarbon in the above (2) include isoprene, butadiene, 3-methyl-1,2-butadiene, 2,3-dimethyl 1,3-butadiene, pentadiene, hexadiene, octadiene, 1,3,5- Examples include hexatriene, cyclopentadiene, cyclohexadiene, and trivinylcyclohexane.

  Specific examples of the ester group-containing vinyl monomer in (3) above include, for example, diallyl maleate, diallyl phthalate, divinyl adipate, diallyl adipate, divinyl fumarate, divinyl maleate, and itaconic acid. Divinyl, vinyl cinnamate, vinyl crotonic acid, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meta ) Acrylate, glycerol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,2-cyclohexanediol di (meth) acrylate, 1,3-cyclohexanediol di (meth) acrylate Rate, 1,4-cyclohexanediol di (meth) acrylate, vinyl (meth) acrylate, polyethylene glycol (molecular weight 300) di (meth) acrylate, polypropylene glycol (molecular weight 500), such as diacrylate.

  Specific examples of the sulfone group-containing vinyl monomers, vinyl sulfate monoesters and salts thereof in (4) above include, for example, divinyl sulfide, divinyl sulfone, divinyl sulfoxide, diallyl disulfide. , Etc. Specific examples of the phosphate group-containing vinyl monomer in (5) described above include, for example, triallyl phosphate ester, tri (4-vinylphenyl) phosphate ester, tri (4-vinylbenzyl) phosphate ester, diallylmethyl. Examples include phosphoric acid ester, di (4-vinylphenyl) methyl phosphoric acid ester, di (4-vinylbenzyl) methyl phosphoric acid ester, diallylphenyl phosphate and the like.

  The hydroxyl group-containing vinyl monomer in (6) above. Divinyl glycol (1,5-hexadiene-3,4-diol), 1,2-divinyloxy-3-propanol, 1,3-divinyloxy-2-propanol and the like. (7) Specific examples of the nitrogen-containing vinyl monomer include diallylamine, triallylamine, diallyl isocyanurate, diallyl cyanurate, 1-cyanobutadiene, methylenebisacrylamide, bismaleimide, and the like.

  Specific examples of the halogen element-containing vinyl monomer in (8) described above include 1,4-divinylperfluorobutane, chloroprene, diallylamine hydrochloride, and the like. Specific examples of the above-mentioned (9) carboxyl group-containing vinyl monomers and salts thereof include carboxyl groups such as monoallyl maleate, monoallyl phthalate, monovinyl fumarate, monovinyl maleate, monovinyl itaconate, and the like. Examples thereof include vinyl-containing monomers, and alkali metal salts and alkaline earth metal salts thereof. Examples of the alkali metal salt include sodium salt and potassium salt. Examples of alkaline earth metal salts include calcium salts and magnesium salts.

  Specific examples of the silicon-containing vinyl monomer in (10) described above include, for example, divinyldimethylsilane, 1,3-divinyltetramethyldisiloxane, 1,1,3,3-tetramethyl-1, 3-divinyldisiloxane, and the like.

  Specific examples of the monomer in (11) described above include monomers described in WO 2005/061566, PCT / JP2006 / 308634, and the like.

Specific examples of the vinyl monomer obtained by introducing an initiator site into the vinyl monomer structure in (12) described above include 2- (2-bromopropionyloxy) ethyl acrylate, 2- (2 -Bromopropionyloxy) ethyl acrylate, 2- (2-bromopropionyloxy) butyl acrylate, 2- (2-bromopropionyloxy) ethyl methacrylate, 2- (2-bromopropionyloxy) ethyl methacrylate, m- (1 -Chloroethyl) styrene, monomers represented by the following formula (I), and the like.

Y in the above formula (I) represents a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms. The number of carbon atoms in Y is preferably 1-8. The more preferable carbon number in Y is 1-6. Y in the above formula (I) may contain a hydroxyl group or a carboxyl group.

Specific examples of Y in the formula (I) include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, an amylene group, a hexylene group, and a cyclohexylene group. . Y in the formula (I) is a group in which the above groups are bonded, or a group in which “—O—”, “—CO—”, or “—COO—” is interposed in each of the above groups. Is mentioned.

Among the groups described above, Y in the formula (I) is preferably an alkylene group having 1 to 8 carbon atoms. Among the alkylene groups having 1 to 8 carbon atoms, Y in the formula (I) is more preferably a linear alkylene group having 1 to 8 carbon atoms. More preferable alkylene groups include, for example, a methylene group, an ethylene group, a —OCH ₂ — group, and a —OCH ₂ CH ₂ — group. The monomer corresponding to the above formula (I) represents a halogen atom (halogen group) such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Specifically, as the monomer corresponding to the above formula (I), for example, among the halogen atoms described above, a chlorine atom and a bromine atom are preferable.

Among the vinyl monomers in which the initiator site is introduced into the vinyl monomer structure in (12) described above, as the monomer represented by the above formula (I), specifically, for example, chloromethylstyrene , Bromomethylstyrene, p- (1-chloroethyl) styrene, bromo (4-vinylphenyl) phenylmethane, 1-bromo-1- (4-vinylphenyl) propan-2-one, 3-bromo-3- (4 -Vinylphenyl) propanol, etc.

  As a monomer which comprises the core part of a star polymer, in addition to the monomer applicable to said (1)-(12), another monomer can be included. The other monomer is not particularly limited as long as it is a monomer capable of radical polymerization, and can be appropriately selected according to the purpose. Examples of other monomers capable of radical polymerization include (meth) acrylic acid and (meth) acrylic acid esters, vinyl benzoic acid, vinyl benzoic acid esters, styrenes, allyl compounds, vinyl ethers, and vinyl esters. And a compound having a radical polymerizable unsaturated bond selected from the above.

  Specific examples of the (meth) acrylic acid esters mentioned as other monomers capable of radical polymerization include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, and tert-acrylate. -Butyl, 2-methylbutyl acrylate, 2-methylpentyl acrylate, 2-ethylbutyl acrylate, 3-methylpentyl acrylate, 2-methylhexyl acrylate, 3-methylhexyl acrylate, triethylcarbyl acrylate, acrylic 1-methyl-1-cyclopentyl acrylate, 1-ethyl-1-cyclopentyl acrylate, 1-methyl-1-cyclohexyl acrylate, 1-ethyl-1-cyclohexyl acrylate, 1-methylnorbornyl acrylate, 1 acrylic acid -Ethylnorbornyl, acrylic acid 2- Tyl-2-adamantyl, 2-ethyl-2-adamantyl acrylate, 3-hydroxy-1-adamantyl acrylate, tetrahydrofuranyl acrylate, tetrahydropyranyl acrylate, 1-methoxyethyl acrylate, 1-ethoxyethyl acrylate 1-n-propoxyethyl acrylate, 1-isopropoxyethyl acrylate, n-butoxyethyl acrylate, 1-isobutoxyethyl acrylate, 1-sec-butoxyethyl acrylate, 1-tert-butoxyethyl acrylate 1-tert-amyloxyethyl acrylate, 1-ethoxy-n-propyl acrylate, 1-cyclohexyloxyethyl acrylate, methoxypropyl acrylate, ethoxypropyl acrylate, 1-methoxy-1-methyl-ethyl acrylate 1-ethoxy-1-methyl-ethyl acrylate, trimethylsilyl acrylate, triethylsilyl acrylate, dimethyl-tert-butylsilyl acrylate, α- (acryloyl) oxy-γ-butyrolactone, β- (acryloyl) oxy-γ-butyrolactone , Γ- (acryloyl) oxy-γ-butyrolactone, α-methyl-α- (acryloyl) oxy-γ-butyrolactone, β-methyl-β- (acryloyl) oxy-γ-butyrolactone, γ-methyl-γ- (acroyl) ) Oxy-γ-butyrolactone, α-ethyl-α- (acryloyl) oxy-γ-butyrolactone, β-ethyl-β- (acryloyl) oxy-γ-butyrolactone, γ-ethyl-γ- (acryloyl) oxy-γ- Butyrolactone, α- (acryloyl) oxy-δ-valerolactone, β- (a Cloyl) oxy-δ-valerolactone, γ- (acryloyl) oxy-δ-valerolactone, δ- (acryloyl) oxy-δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valero Lactone, β-methyl-β- (acryloyl) oxy-δ-valerolactone, γ-methyl-γ- (acryloyl) oxy-δ-valerolactone, δ-methyl-δ- (acryloyl) oxy-δ-valerolactone, α-ethyl-α- (acryloyl) oxy-δ-valerolactone, β-ethyl-β- (acryloyl) oxy-δ-valerolactone, γ-ethyl-γ- (acryloyl) oxy-δ-valerolactone, δ- Ethyl-δ- (acryloyl) oxy-δ-valerolactone, 1-methylcyclohexyl acrylate, adamantyl acrylate, 2- (2-methyl acrylate) Chill) adamantyl, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, glycidyl acrylate, benzyl acrylate, phenyl acrylate, naphthyl acrylate, methacrylic acid Methyl, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-methylbutyl methacrylate, 2-methylpentyl methacrylate, 2-ethylbutyl methacrylate, 3-methylpentyl methacrylate, methacrylic acid 2-methylhexyl, 3-methylhexyl methacrylate, triethylcarbyl methacrylate, 1-methyl-1-cyclopentyl methacrylate, 1-ethyl-1-cyclopentyl methacrylate, meta 1-methyl-1-cyclohexyl laurate, 1-ethyl-1-cyclohexyl methacrylate, 1-methylnorbornyl methacrylate, 1-ethylnorbornyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-methacrylic acid 2- Ethyl-2-adamantyl, 3-hydroxy-1-adamantyl methacrylate, tetrahydrofuranyl methacrylate, tetrahydropyranyl methacrylate, 1-methoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-n-propoxyethyl methacrylate, 1-isopropoxyethyl methacrylate, n-butoxyethyl methacrylate, 1-isobutoxyethyl methacrylate, 1-sec-butoxyethyl methacrylate, 1-tert-butoxyethyl methacrylate, 1-tert-methacrylate Miroxyethyl, 1-ethoxy-n-propyl methacrylate, 1-cyclohexyloxyethyl methacrylate, methoxypropyl methacrylate, ethoxypropyl methacrylate, 1-methoxy-1-methyl-ethyl methacrylate, 1-ethoxy-1-methacrylate Methyl-ethyl, trimethylsilyl methacrylate, triethylsilyl methacrylate, dimethyl-tert-butylsilyl methacrylate, α- (methacryloyl) oxy-γ-butyrolactone, β- (methacryloyl) oxy-γ-butyrolactone, γ- (methacryloyl) oxy- γ-butyrolactone, α-methyl-α- (methacryloyl) oxy-γ-butyrolactone, β-methyl-β- (methacryloyl) oxy-γ-butyrolactone, γ-methyl-γ- (methacryloyl) oxy-γ-butyrolacto , Α-ethyl-α- (methacloyl) oxy-γ-butyrolactone, β-ethyl-β- (methacroyl) oxy-γ-butyrolactone, γ-ethyl-γ- (methacloyl) oxy-γ-butyrolactone, α- ( Methacryloyl) oxy-δ-valerolactone, β- (methacryloyl) oxy-δ-valerolactone, γ- (methacryloyl) oxy-δ-valerolactone, δ- (methacryloyl) oxy-δ-valerolactone, α-methyl-α -(4-vinylbenzoyl) oxy-δ-valerolactone, β-methyl-β- (methacryloyl) oxy-δ-valerolactone, γ-methyl-γ- (methacryloyl) oxy-δ-valerolactone, δ-methyl- δ- (methacryloyl) oxy-δ-valerolactone, α-ethyl-α- (methacryloyl) oxy-δ-valerolactone, β- Til-β- (methacloyl) oxy-δ-valerolactone, γ-ethyl-γ- (methacloyl) oxy-δ-valerolactone, δ-ethyl-δ- (methacloyl) oxy-δ-valerolactone, methacrylic acid 1- Methyl cyclohexyl, adamantyl methacrylate, 2- (2-methyl) adamantyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2-dimethylhydroxypropyl methacrylate, 5-hydroxypentyl methacrylate, trimethylol methacrylate Examples include propane, glycidyl methacrylate, benzyl methacrylate, phenyl methacrylate, naphthyl methacrylate, and the like.

  Specific examples of the vinyl benzoate listed as other monomers capable of radical polymerization include, for example, methyl vinyl benzoate, ethyl vinyl benzoate, propyl vinyl benzoate, n-butyl vinyl benzoate, and vinyl. Tert-Butyl benzoate, 2-methylbutyl vinylbenzoate, 2-methylpentyl vinylbenzoate, 2-ethylbutyl vinylbenzoate, 3-methylpentyl vinylbenzoate, 2-methylhexyl vinylbenzoate, 3-methylvinylbenzoate Hexyl, triethylcarbyl vinylbenzoate, 1-methyl-1-cyclopentyl vinylbenzoate, 1-ethyl-1-cyclopentyl vinylbenzoate, 1-methyl-1-cyclohexyl vinylbenzoate, 1-ethyl-1 vinylbenzoate -Cyclohexyl, vinylbenzoic acid 1- Tilnorbornyl, 1-ethylnorbornyl vinylbenzoate, 2-methyl-2-adamantyl vinylbenzoate, 2-ethyl-2-adamantyl vinylbenzoate, 3-hydroxy-1-adamantyl vinylbenzoate, tetrahydrofuranyl vinylbenzoate, Tetrahydropyranyl vinylbenzoate, 1-methoxyethyl vinylbenzoate, 1-ethoxyethyl vinylbenzoate, 1-n-propoxyethyl vinylbenzoate, 1-isopropoxyethyl vinylbenzoate, n-butoxyethyl vinylbenzoate, 1-isobutoxyethyl vinylbenzoate, 1-sec-butoxyethyl vinylbenzoate, 1-tert-butoxyethyl vinylbenzoate, 1-tert-amyloxyethyl vinylbenzoate, 1-ethoxy-n-propyl vinylbenzoate Vinyl repose 1-cyclohexyloxyethyl acid, methoxypropyl vinylbenzoate, ethoxypropyl vinylbenzoate, 1-methoxy-1-methyl-ethyl vinylbenzoate, 1-ethoxy-1-methyl-ethyl vinylbenzoate, trimethylsilyl vinylbenzoate, Triethylsilyl vinylbenzoate, dimethyl-tert-butylsilyl vinylbenzoate, α- (4-vinylbenzoyl) oxy-γ-butyrolactone, β- (4-vinylbenzoyl) oxy-γ-butyrolactone, γ- (4-vinylbenzoyl) ) Oxy-γ-butyrolactone, α-methyl-α- (4-vinylbenzoyl) oxy-γ-butyrolactone, β-methyl-β- (4-vinylbenzoyl) oxy-γ-butyrolactone, γ-methyl-γ- ( 4-vinylbenzoyl) oxy-γ-butyrolactone, α-ethyl-α- (4-vinylbenzoyl) oxy-γ-butyrolactone, β-ethyl-β- (4-vinylbenzoyl) oxy-γ-butyrolactone, γ-ethyl-γ- (4-vinylbenzoyl) oxy- γ-butyrolactone, α- (4-vinylbenzoyl) oxy-δ-valerolactone, β- (4-vinylbenzoyl) oxy-δ-valerolactone, γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ -(4-vinylbenzoyl) oxy-δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-methyl-β- (4-vinylbenzoyl) oxy-δ-valero Lactone, γ-methyl-γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ-methyl-δ- (4-vinylbenzoyl) oxy-δ-ba Lerolactone, α-ethyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-ethyl-β- (4-vinylbenzoyl) oxy-δ-valerolactone, γ-ethyl-γ- (4-vinyl Benzoyl) oxy-δ-valerolactone, δ-ethyl-δ- (4-vinylbenzoyl) oxy-δ-valerolactone, 1-methylcyclohexyl vinylbenzoate, adamantyl vinylbenzoate, 2- (2-methylvinylbenzoate) ) Adamantyl, chloroethyl vinylbenzoate, 2-hydroxyethyl vinylbenzoate, 2,2-dimethylhydroxypropyl vinylbenzoate, 5-hydroxypentyl vinylbenzoate, trimethylolpropane vinylbenzoate, glycidyl vinylbenzoate, vinylbenzoic acid Benzyl, phenyl vinyl benzoate, vinyl benzo Acid naphthyl, and the like.

  Specific examples of styrenes listed as other monomers capable of radical polymerization include, for example, styrene, benzyl styrene, trifluoromethyl styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, trichlorostyrene, and tetrachlorostyrene. , Pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene, vinylnaphthalene, etc. Can be mentioned.

  Specific examples of allyl compounds listed as other monomers capable of radical polymerization include, for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate. , Allyl acetoacetate, allyl lactate, allyloxyethanol, and the like.

  Specific examples of vinyl ethers listed as other monomers capable of radical polymerization include, for example, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1- Methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl Tril ether, vinyl chlorfe Ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether, and the like.

  Specific examples of vinyl esters listed as other monomers capable of radical polymerization include, for example, vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl barate, vinyl caproate, Examples include vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinylphenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexyl carboxylate, and the like.

  Among the monomers corresponding to the above (1) to (11), as monomers constituting the core of the star polymer, aromatic vinyl hydrocarbons, vinyl hydrocarbons, ester group-containing vinyl monomers, Hydroxyl group-containing vinyl monomers, carboxyl group-containing vinyl monomers and salts thereof, vinyl monomers in which an initiator site is introduced into the vinyl monomer structure, and the like are preferable. Among the other monomers capable of radical polymerization described above, monomers constituting the core of the star branch polymer include (meth) acrylic acid, (meth) acrylic acid esters, vinyl benzoic acid, and vinyl benzoic acid ester. , Vinyl ethers, vinyl esters and the like are preferable.

  The amount of the monomer represented by the above (1) to (12) in the star polymer is preferably 5 to 100 mol%, preferably 20 to 100 mol%, based on all monomers forming the core of the star polymer. More preferably, it is more preferably 50 to 100 mol%. If it exists in the range mentioned above, since the core part of a star polymer takes a spherical form advantageous to the entanglement suppression between the molecules which comprise the core part of a star polymer, it is preferable.

  The monomer corresponding to the core part is preferably contained in an amount of 10 to 99 mol% with respect to all monomers used in the synthesis of the star polymer.

(Polymerization initiator)
For the synthesis of the star polymer, 9-BBN is used as a polymerization initiator. When 9-BBN is used as a polymerization initiator, it is preferable that 9-BBN is mixed in a molar amount of 0.01 to 0.1 times with respect to the monomer.

(Solvent and coordination solvent)
Next, the solvent and the coordinating solvent used for the synthesis of the star polymer will be described. Examples of the solvent used for the synthesis of the star polymer include benzene, toluene, chlorobenzene, and the like. Examples of the coordinating solvent used for the synthesis of the star polymer include dioxane, THF, diethylene glycol dimethyl ether, p-chloroaniline, and the like. The coordinating solvent contributes to stabilization of the terminal dormant species by coordinating weakly to the vacant orbitals of boron atoms in 9-BBN.

Thereby, the coordinating solvent suppresses the polymerization reaction of the monomer described above. The coordinating solvent also contributes to the stabilization of 9-BBN itself. The ratio of the coordinating solvent to the solvent is preferably 1/9 to 9/1.
For example, when chloroaniline is used as the coordinating solvent, the amount of chloroaniline with respect to 9-BBN is preferably 0.5 to 5 equivalents, and more preferably 1 to 3 equivalents.

(Star polymer synthesis process)
Next, the synthesis process of the star polymer will be described. When synthesizing a star polymer, a predetermined monomer, a polymerization initiator, a solvent, and a coordinating solvent among the above-mentioned various monomers are mixed, and the monomer, the polymerization initiator, the solvent, and the coordinating solvent are mixed. The reaction system is heated to initiate living radical polymerization in the reaction system. Thereby, the arm part in a star polymer is formed. Living radical polymerization is carried out for 0.5 to 50 hours while maintaining the temperature of the entire reaction system at 20 to 150 ° C.
The concentration of the monomer constituting the arm part is desirably 1 to 100% by weight, more preferably 1 to 50% by weight, based on the total amount of the reaction.

Subsequently, divinyl monomer is added to the heated reaction system. As a result, in the reaction system, a star polymer is synthesized with the added divinyl monomer as the core part and the polymer synthesized by the above-mentioned living radical polymerization as the arm part.
The ratio of the monomer that constitutes the arm part to the monomer that constitutes the core part can be appropriately adjusted depending on the purpose and application, but the monomer constituting the arm part is 1 It is desirable that it is -100 times mol.

  After adding the divinyl monomer, the living radical polymerization is stopped within a predetermined time. Here, the predetermined time is a time required until the synthesis of the star polymer proceeds until the target molecular weight level is reached, and is a time that can be appropriately set according to the molecular weight of the target star polymer. The method for terminating the living radical polymerization is not particularly limited, and for example, a method such as cooling the reaction system during the living radical polymerization can be used.

  The above-mentioned star polymer has a weight average molecular weight (M) of preferably 500 to 200,000, more preferably 2,000 to 100,000, and most preferably 3,000 to 50,000. When the weight average molecular weight (M) of the star polymer is in such a range, the resist containing the star polymer has good film formability and has a shape of a processing pattern formed in the lithography process, and thus has a shape. Can keep. It also has excellent dry etching resistance and good surface roughness.

  The weight average molecular weight (M) of the above-mentioned star polymer was determined by measuring GPC and MALLS values.

(Molecular structure)
Next, the molecular structure of the above-described star polymer will be described. The shape of the star polymer is determined based on the difference between the GPC measurement value and the MALLS value by using the GPC measurement value and the MALLS value described above. When the value of GPC measurement and the value of MALLS differ greatly, it can be determined that the star polymer is spherical. The absolute molecular weight was measured by multi-angle light scattering (He-Ne laser, DAWN DSP-F, manufactured by Wyatt Technology) under the same conditions as those for GPC measurement.

  The polydispersity (Mw / Mn) in the star polymer is preferably 1 to 5, and more preferably 1 to 3. If it is in such a range, there is no possibility of causing adverse effects such as insolubilization after exposure, which is desirable.

  The above-mentioned star polymer has a weight average molecular weight (M) of preferably 500 to 400,000, more preferably 2,000 to 200,000, and most preferably 3,000 to 100,000. When the weight average molecular weight (M) of the star polymer is in such a range, the resist containing the star polymer has good film formability and has a shape of a processing pattern formed in the lithography process, and thus has a shape. Can keep. It also has excellent dry etching resistance and good surface roughness.

(Use of star polymer)
Examples of the use of the star polymer described above include a photoresist. When the above-mentioned star polymer is used for a photoresist, specifically, for example, as an ultraviolet curable resin for producing printing plate making, hard coat agent, antireflection film, dental material, adhesive / adhesive agent, paint, etc. Is mentioned.

  The above-mentioned star polymer can be used, for example, as a dispersion of pigments, fine metal particles, organic EL, dye laser color filter resist, as a stabilizer, or as an optical material such as an optical fiber or an optical waveguide. , Etc.

(Resist composition)
Next, a resist composition using a star polymer will be described. When a star polymer is used as the resist composition, the metal is removed after the star polymer is polymerized.

(Metal removal)
Here, metal removal will be described. In removing the metal, a small amount of metal remaining in the polymer is reduced after the conversion of the terminal substituent described above. As a method for reducing a small amount of metal remaining in the synthesized star polymer, for example, the following methods (S-1) to (S-2) can be performed singly or in combination.

(S-1) Liquid extraction is performed with an aqueous solution of an organic compound having a chelating ability, an inorganic acid aqueous solution, and pure water.
(S-2) Adsorbent and ion exchange resin are used.

  Examples of the organic solvent used for liquid-liquid extraction in the above (S-1) include halogenated hydrocarbons such as chlorobenzene and chloroform, acetates such as ethyl acetate, n-butyl acetate and isoamyl acetate, methyl ethyl ketone, Ketones such as methyl isobutyl ketone, cyclohexanone, 2-heptane, 2-pentanone, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate glycol ether acetates such as ethylene glycol monomethyl ether acetate, toluene, xylene and the like Aromatic hydrocarbons are preferred.

  More preferably, examples of the organic solvent used for the liquid-liquid extraction in (S-1) include chloroform, methyl isobutyl ketone, and ethyl acetate. These solvents may be used alone or in combination of two or more. When liquid-liquid extraction is performed according to the above (S-1), the mass% of the star polymer with respect to the organic solvent is preferably about 1 to 30 mass%. Furthermore, the mass% of the resist polymer intermediate with respect to the preferable organic solvent is about 5 to 20 mass%.

  Examples of organic compounds having chelating ability used for liquid-liquid extraction in accordance with (S-1) above include organic carboxylic acids such as formic acid, acetic acid, oxalic acid, citric acid, gluconic acid, tartaric acid, and malonic acid. And amino carbonates such as nitrilotriacetic acid, ethylenediaminetetraacetic acid, and diethylenetriaminopentaacetic acid, and hydroxyaminocarbonate. Examples of the inorganic acid having chelating ability used for liquid-liquid extraction in the above (S-1) include hydrochloric acid and sulfuric acid.

  When liquid-liquid extraction is performed according to (S-1) above, the concentration of the organic compound having chelating ability and the inorganic acid in the aqueous solution is preferably 0.05 wt% to 10 wt%, for example. Note that the concentration of the organic compound having chelating ability and the inorganic acid in the aqueous solution during liquid-liquid extraction in the above (S-1) varies depending on the chelating ability of the compound.

  In the case of using an aqueous solution of an organic compound having a chelating ability and an inorganic acid aqueous solution for removing a metal, an aqueous solution of an organic compound having a chelating ability and an inorganic acid aqueous solution may be mixed and used. An aqueous solution and an inorganic acid aqueous solution may be used separately. When the aqueous solution of the organic compound having chelating ability and the aqueous inorganic acid solution are used separately, either the aqueous solution of the organic compound having chelating ability or the aqueous inorganic acid solution may be used first.

  When removing the metal, when using an aqueous solution of an organic compound having a chelating ability and an aqueous inorganic acid solution separately, it is more preferable to perform the aqueous inorganic acid solution in the latter half. This is because an aqueous solution of an organic compound having a chelating ability is effective for removing a copper catalyst and a polyvalent metal, and an inorganic acid aqueous solution is effective for removing a monovalent metal derived from a laboratory instrument or the like.

  Therefore, even when an aqueous solution of an organic compound having chelating ability and an inorganic acid aqueous solution are mixed and used, it is desirable to wash the shell portion using a single inorganic acid aqueous solution in the latter half. The number of extraction is not particularly limited, but it is desirable to perform the extraction 2 to 5 times, for example. In order to prevent mixing of metals derived from laboratory instruments and the like, it is preferable to use preliminarily cleaned laboratory instruments used particularly in a state where copper ions are reduced. The method of preliminary cleaning is not particularly limited, and examples thereof include cleaning with an aqueous nitric acid solution.

  The number of washings with the inorganic acid aqueous solution alone is preferably 1 to 5 times. Monovalent metals can be sufficiently removed by washing with an inorganic acid aqueous solution alone 1 to 5 times. Moreover, in order to remove the remaining acid component, it is preferable to perform an extraction process with pure water at the end to completely remove the acid. The number of washings with pure water is preferably 1 to 5 times. The remaining acid can be sufficiently removed by washing with pure water 1 to 5 times.

  The ratio of the reaction solvent containing the produced star polymer (hereinafter simply referred to as “reaction solvent”) to the aqueous solution of an organic compound having a chelating ability, the aqueous solution of an inorganic acid, and pure water at the time of washing in removing the metal is any The volume ratio is preferably 1: 0.1 to 1:10. A more preferable ratio is 1: 0.5 to 1: 5 in terms of volume ratio. By washing with a solvent having such a ratio, the metal can be easily removed at an appropriate number of times. Accordingly, the operation can be facilitated and the operation can be simplified, which is suitable for efficiently producing a star polymer. The weight concentration of the resist polymer intermediate dissolved in the reaction solvent is usually preferably about 1 to 30% by mass with respect to the solvent.

  When liquid-liquid extraction is performed in accordance with the above (S-1), for example, a mixed solvent (hereinafter simply referred to as “mixing”) in which an aqueous solution of an organic compound having chelating ability and an aqueous solution of an organic compound, an inorganic acid aqueous solution, and pure water are mixed. Solvent ”) is separated into two layers, and the aqueous layer to which the metal ions have been transferred is removed by decantation or the like. As a method of separating the mixed solvent into two layers, for example, an aqueous solution of an organic compound having a chelating ability, an inorganic acid aqueous solution, and pure water are added to the reaction solvent, and the mixture is sufficiently mixed by stirring and then allowed to stand. By doing. Further, as a method for separating the mixed solvent into two layers, for example, a centrifugal separation method may be used.

  The liquid-liquid extraction process in (S-1) is preferably performed at a temperature of 10 to 50 ° C., for example. The liquid-liquid extraction process in (S-1) is more preferably performed at a temperature of 20 to 40 ° C.

  The blend amount of the star polymer in the resist composition using the star polymer (hereinafter simply referred to as “resist composition”) is preferably 4 to 40% by mass, and 4 to 20% by mass with respect to the total amount of the resist composition. More preferred.

  The resist composition contains the above-described star polymer and a photoacid generator. The resist composition may further contain an acid diffusion inhibitor (acid scavenger), a surfactant, other components, a solvent, and the like, if necessary.

The photoacid generator contained in the resist composition is not particularly limited as long as it generates an acid when irradiated with ultraviolet rays, X-rays, electron beams, and the like, and various known photoacid generators can be used. It can be suitably selected from the inside according to the purpose. Specifically, examples of the photoacid generator include onium salts, sulfonium salts, halogen-containing triazine compounds, sulfone compounds, sulfonate compounds, aromatic sulfonate compounds, and sulfonate compounds of N-hydroxyimide.

  Examples of the onium salt contained in the above-mentioned photoacid generator include diaryl iodonium salts, triaryl selenonium salts, triaryl sulfonium salts, and the like. Examples of the diaryliodonium salt include diphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium hexafluoroantimonate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium tetrafluoroborate, Examples thereof include bis (4-tert-butylphenyl) iodonium hexafluorophosphate, bis (4-tert-butylphenyl) iodonium hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, and the like.

  Specific examples of the triarylselenonium salt contained in the onium salt described above include, for example, triphenylselenonium hexafluorophosphonium salt, triphenylselenonium borofluoride salt, triphenylselenonium hexafluoroantimonate salt, and the like. Is mentioned. Examples of the triarylsulfonium salt contained in the above onium salt include, for example, triphenylsulfonium hexafluorophosphonium salt, triphenylsulfonium hexafluoroantimonate salt, diphenyl-4 monothiophenoxyphenylsulfonium hexafluoroantimonate salt, diphenyl -4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate salt, and the like.

  Examples of the sulfonium salt contained in the photoacid generator include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4 -Methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenyl Sulfonium hexafluorophosph 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium hexafluoroantimonate, 1- (2-naphthoylmethyl) thiolanium trifluoroantimonate, 4-hydroxy Examples include -1-naphthyldimethylsulfonium hexafluoroantimonate and 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate.

  Specific examples of the halogen-containing triazine compound contained in the above-described photoacid generator include, for example, 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4,6 -Tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethylto-1,3,5-triazine, 2- (4-chlorophenyl) -4,6-bis ( Trichloromethyl) -1,3,5-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethylto-1,3,5-triazine, 2- (4-methoxy-1-naphthyl)- 4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3 , 5-Triazi 2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) ) -1,3,5-triazine, 2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (2,4-dimethoxystyryl)- 4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (2-methoxystyryl) 4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-butoxy Styryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-benzyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, Etc.

  Specific examples of the sulfone compound contained in the photoacid generator described above include diphenyldisulfone, di-p-tolyldisulfone, bis (phenylsulfonyl) diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, and bis (p -Tolylsulfonyl) diazomethane, bis (4-tert-butylphenylsulfonyl) diazomethane, bis (2,4-xylylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, (benzoyl) (phenylsulfonyl) diazomethane, phenylsulfonyl And acetophenone.

  Specific examples of the aromatic sulfonate compound contained in the photoacid generator include α-benzoylbenzyl p-toluenesulfonate (commonly known as benzoin tosylate), β-benzoyl-β-hydroxyphenethyl p-toluenesulfonate. (Commonly known as α-methylol benzoin tosylate), 1,2,3-benzenetriyl trismethanesulfonate, 2,6-dinitrobenzyl p-toluenesulfonate, 2-nitrobenzyl p-toluenesulfonate, 4-nitrobenzyl p-toluene And sulfonates.

  Specific examples of the sulfonate compound of N-hydroxyimide contained in the above-described photoacid generator include N- (phenylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) succinimide, N- (p -Chlorophenylsulfonyloxy) succinimide, N- (cyclohexylsulfonyloxy) succinimide, N- (1-naphthylsulfonyloxy) succinimide, n- (benzylsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) naphth Ruimido, N-(10- camphorsulfonic sulfonyloxy) naphthalimide, and the like.

  Of the various photoacid generators described above, sulfonium salts are preferred. In particular, triphenylsulfonium trifluoromethanesulfonate; sulfone compounds, particularly bis (4-tert-butylphenylsulfonyl) diazomethane and bis (cyclohexylsulfonyl) diazomethane are preferred.

  The above-mentioned photoacid generators may be used alone or in combination of two or more. There is no restriction | limiting in particular as a compounding rate of a photo-acid generator, Although it can select suitably according to the objective, 0.1-30 mass parts is preferable with respect to 100 mass parts of star polymers of this invention. A more preferable blending ratio of the photoacid generator is 0.1 to 10 parts by mass.

  The acid diffusion inhibitor contained in the resist composition is a component that controls the diffusion phenomenon of the acid generated from the acid generator upon exposure in the resist film and suppresses an undesirable chemical reaction in the non-exposed region. There is no particular limitation. The acid diffusion inhibitor contained in the resist composition can be appropriately selected from known acid diffusion inhibitors according to the purpose.

  Examples of the acid diffusion inhibitor contained in the resist composition include a nitrogen-containing compound having one nitrogen atom in the same molecule, a compound having two nitrogen atoms in the same molecule, and three nitrogen atoms in the same molecule. Examples thereof include polyamino compounds and polymers, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds.

  Examples of the arsenic-containing compound having one nitrogen atom in the same molecule mentioned as the acid diffusion inhibitor include mono (cyclo) alkylamine, di (cyclo) alkylamine, and tri (cyclo) alkylamine. , Aromatic amines, and the like. Specific examples of the mono (cyclo) alkylamine include n-hexylamine, n-hexylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine, and the like.

  Examples of the di (cyclo) alkylamine contained in the nitrous acid compound having one nitrogen atom in the same molecule include di-n-butylamine, di-n-benzylamine, di-n-hexylamine, di- Examples include n-hebutylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, and the like.

  Examples of the tri (cyclo) alkylamine contained in the nitrous acid compound having one nitrogen atom in the same molecule include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-benzylamine, Examples include tri-n-hexylamine, tri-n-hexylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, cyclohexyldimethylamine, methyldicyclohexylamine, and tricyclohexylamine.

  Examples of the aromatic amine contained in the arsenic compound having one nitrogen atom in the same molecule include aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4 -Methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, and the like.

  Examples of the nitrogen-containing compound having two nitrogen atoms in the same molecule mentioned as the acid diffusion inhibitor include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexa Methylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4- Hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene Zen, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, and the like.

  Examples of the polyamino compound or polymer having 3 or more nitrogen atoms in the same molecule mentioned as the acid diffusion inhibitor include polyethyleneimine, polyallylamine, and N- (2-dimethylaminoethyl) acrylamide. Coalescence, etc.

  Examples of the amide group-containing compound mentioned as the acid diffusion inhibitor include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, and Nt-butoxy. Carbonyl di-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, N, N- Di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4, -diaminodiphenylmethane, N, N '-Di-t-butoxycarbonylhexamethylenediamine, N, N, N'N'-tetra t-butoxycarbonylhexamethylenediamine N, N′-di-t-butoxycarbonyl-1,7-diaminohexane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N ′ -Di-t-butoxycarbonyl-1,9-diaminononane, N, N, -di-t-butoxycarbonyl-1,10-diaminodecane, N, N, -di-t-butoxycarbonyl-1,12-diamino Dodecane, N, N, -di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt- Butoxycarbonyl-2-phenylbenzimidazole, formamide, N-methylformamide, N, N-dimethylformua De, acetamide, N- methylacetamide, N, N- dimethylacetamide, propionamide, benzamide, pyrrolidone, N- methylpyrrolidone, and the like.

  Specific examples of the urea compound mentioned as the acid diffusion inhibitor include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethyl. Examples include urea, 1,3-diphenylurea, tri-n-butylthiourea, and the like.

  Specific examples of the nitrogen-containing heterocyclic compound mentioned as the acid diffusion inhibitor include, for example, imidazole, 4-methylimidazole, 4-methyl-2-phenylimigzole, benzimidazole, 2-phenylbenze. Imidazole, pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinic acid Amide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, piverazine, 1- (2-hydroxyethyl) piverazine, pyrazine, pyrazole, viridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2- Propanediol, morpholy , 4-methylmorpholine, 1,4 Jimechipiberajin, 1,4-diazabicyclo [2.2.2] octane, and the like.

  Said acid diffusion inhibitor can be used individually or in mixture of 2 or more types. As a compounding quantity of said acid diffusion inhibitor, 0.1-1000 mass parts is preferable with respect to 100 mass parts of photo-acid generators. A more preferable blending amount of the acid diffusion inhibitor is 0.5 to 10 parts by mass with respect to 100 parts by mass of the photoacid generator. In addition, there is no restriction | limiting in particular as a compounding quantity of said acid diffusion inhibitor, According to the objective, it can select suitably.

  As the surfactant contained in the resist composition, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester nonionic surfactant, fluorine-based surfactant, Examples thereof include silicon-based surfactants. The surfactant contained in the resist composition is not particularly limited as long as it has a function of improving coatability, striation, developability, etc., and is appropriately selected from known ones according to the purpose. be able to.

  Specific examples of the polyoxyethylene alkyl ether listed as the surfactant contained in the resist composition include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl. Ether, etc. Examples of the polyoxyethylene alkylallyl ether listed as the surfactant contained in the resist composition include polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, and the like.

  Specific examples of the sorbitan fatty acid ester exemplified as the surfactant contained in the resist composition include sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, And sorbitan tristearate. Specific examples of nonionic surfactants of polyoxyethylene sorbitan fatty acid esters listed as surfactants included in the resist composition include polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monopalmitate. , Polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, and the like.

  Specific examples of the fluorosurfactant listed as the surfactant contained in the resist composition include F-top EF301, EF303, and EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), MegaFuck F171 and F173. , F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Florard FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC101, SX102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.).

  Examples of the silicon-based surfactant listed as the surfactant contained in the resist composition include organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The various surfactants described above can be used alone or in admixture of two or more. As a compounding quantity of the various surfactant mentioned above, 0.0001-5 mass parts is preferable with respect to 100 mass parts of star polymers produced | generated using the manufacturing method concerning this invention, for example. A more preferable blending amount of the various surfactants described above is 0.0002 to 2 parts by mass with respect to 100 parts by mass of the star polymer produced using the production method according to the present invention. In addition, there is no restriction | limiting in particular as compounding quantity of various surfactant mentioned above, According to the objective, it can select suitably.

  Other components included in the resist composition include, for example, a sensitizer, a dissolution controller, an additive having an acid dissociable group, an alkali-soluble resin, a dye, a pigment, an adhesion aid, an antifoaming agent, a stabilizer, And antihalation agents. Specific examples of sensitizers listed as other components contained in the resist composition include, for example, acetophenones, benzophenones, naphthalenes, biacetyl, eosin, rose bengal, bilenes, anthracenes, and phenothiazines. , Etc. As the above sensitizer, it absorbs radiation energy and transmits the energy to the photoacid generator, thereby increasing the amount of acid generated and improving the apparent sensitivity of the resist composition. If it has an effect, there will be no restriction | limiting in particular. Said sensitizer can be used individually or in mixture of 2 or more types.

  Specific examples of the dissolution control agent exemplified as the other component contained in the resist composition include polyketones and polyspiroketals. There are no particular limitations on the dissolution control agent listed as the other component contained in the resist composition as long as it can more appropriately control the dissolution contrast and dissolution rate when used as a resist. The dissolution control agents listed as other components contained in the resist composition can be used alone or in admixture of two or more.

  Specific examples of the additive having an acid-dissociable group listed as other components included in the resist composition include, for example, t-butyl 1-adamantanecarboxylate, t-butoxycarbonylmethyl 1-adamantanecarboxylate. 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, deoxycholic acid t- Butyl, deoxycholic acid t-butoxycarbonylmethyl, deoxycholic acid 2-fetoxyethyl, deoxycholic acid 2-cyclohexyloxyethyl, deoxycholic acid 3-oxocyclohexyl, deoxycholic acid tetrahydropyranyl, deoxycholic acid mevalonolactone Esters, lithocols tert-butyl, lithocholic acid t-butoxycarbonylmethyl, lithocholic acid 2-ethoxyethyl, lithocholic acid 2-cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester, etc. It is done. The above additives having various acid dissociable groups can be used alone or in admixture of two or more. The additive having various acid dissociable groups is not particularly limited as long as it further improves dry etching resistance, pattern shape, adhesion to the substrate, and the like.

  Specific examples of the alkali-soluble resin listed as the other component contained in the resist composition include poly (4-hydroxystyrene), partially hydrogenated poly (4-hydroxystyrene), and poly (3-hydroxy). Styrene), poly (3-hydroxystyrene), 4-hydroxystyrene / 3-hydroxystyrene copolymer, 4-hydroxystyrene / styrene copolymer, novolac resin, polyvinyl alcohol, polyacrylic acid and the like.

  The weight average molecular weight (Mw) of the alkali-soluble resin is usually 1000 to 1000000, preferably 2000 to 100000. Said alkali-soluble resin can be used individually or in mixture of 2 or more types. The alkali-soluble resin mentioned as the other component contained in the resist composition is not particularly limited as long as it improves the alkali-solubility of the resist composition of the present invention.

  The dyes or pigments listed as other components contained in the resist composition make the latent image in the exposed area visible. By visualizing the latent image of the exposed portion, it is possible to reduce the influence of halation during exposure. Moreover, the adhesion assistant mentioned as another component contained in a resist composition can improve the adhesiveness of a resist composition and a board | substrate.

  Specific examples of the solvent listed as the other component contained in the resist composition include ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionates, alkyl 3-alkoxypropions, Other solvents are mentioned. Solvents listed as other components contained in the resist composition are not particularly limited as long as the other components contained in the resist composition can be dissolved, for example, although those that can be used safely in the resist composition. It can be suitably selected from the inside.

  Specific examples of ketones contained in the solvents listed as other components contained in the resist composition include methyl isobutyl ketone, methyl ethyl ketone, 2-butanone, 2-pentanone, 3-methyl-2-butanone, Examples include 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone, 2-hebutanone, and 2-octanone.

  Specific examples of the cyclic ketone contained in the solvent mentioned as the other component contained in the resist composition include cyclohexanone, cyclopentanone, 3-methylcyclopentanone, 2-methylcyclohexanone, and 2,6. -Dimethylcyclohexanone, isophorone, etc. are mentioned.

  Specific examples of the propylene glycol monoalkyl ether acetate contained in the solvent mentioned as the other component contained in the resist composition include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono- n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol mono-i-butyl ether acetate, propylene glycol mono-SeC-butyl ether acetate, propylene glycol mono-t-butyl ether And acetate.

  Specific examples of the alkyl 2-hydroxypropionate contained in the solvent listed as the other component contained in the resist composition include, for example, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxy N-propyl propionate, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, sec-butyl 2-hydroxyarobionate, t-hydroxy-2-hydroxypropionate Butyl, etc.

  Examples of the alkyl 3-alkoxypropionate contained in the solvent mentioned as the other component contained in the resist composition include methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3 -Ethyl ethoxypropionate, etc.

  Examples of the other solvent included in the solvent listed as the other component included in the resist composition include n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol, and ethylene glycol. Monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol Monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n- Propyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy- Methyl 3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl propylate, ethyl acetate, n-acetate -Propyl, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, Diethyl ether, di-n-hexyl ether, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, γ-ptyrolactone, toluene, xylene, caproic acid, caprylic acid, octane, decane, 1-octanol, 1-nonanol, benzyl alcohol, Examples include benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, ethylene carbonate, propylene carbonate, and the like. Said solvent can be used individually or in mixture of 2 or more types.

  As described above, according to the star polymer synthesis method of the embodiment, a star polymer synthesis method for synthesizing a star polymer in an oxygen-existing atmosphere can be provided. According to the resist composition containing such a star polymer, after being exposed to a pattern in a photoresist, it can be developed and patterned.

  The resist composition can correspond to electron beams, deep ultraviolet (DUV), and extreme ultraviolet (EUV) light sources whose surface smoothness is required on the nano order, and can form fine patterns for manufacturing semiconductor integrated circuits. . Thus, the resist composition containing the star polymer produced by using the production method according to the present invention is preferably used in various fields using semiconductor integrated circuits produced using a light source that emits light having a short wavelength. Can do.

  In addition, in a semiconductor integrated circuit manufactured using a resist composition containing the star polymer of the embodiment, exposure and heating are performed during manufacturing, and after dissolving in an alkaline developer and washing with water or the like, exposure is performed. There is almost no unmelted surface, and a substantially vertical edge can be obtained. As a result, the performance is stabilized, and a fine semiconductor integrated circuit corresponding to an electron beam, a deep ultraviolet (DUV), and an extreme ultraviolet (EUV) light source can be obtained.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to the following examples. In addition, this invention and embodiment concerning this invention are not limited at all by the Example shown below.

(Weight average molecular weight (Mw))
First, the weight average molecular weight (Mw) of the star polymer of an Example is demonstrated. The weight average molecular weight (Mw) of the star polymer of the Examples is prepared by preparing a 0.05% by mass tetrahydrofuran solution, using a GPC HLC-8020 type apparatus manufactured by Tosoh Corporation and a column of TSKgel HXL-M (made by Tosoh Corporation) 2 The books were connected and determined by GPC (Gel Permeation Chromatography) measurement at a temperature of 40 ° C.

  Tetrahydrofuran was used as a mobile solvent for GPC measurement. Polystyrene was used as a standard substance for GPC measurement. Under the same conditions, the absolute molecular weight was measured by multi-angle light scattering (He-Ne laser, DAWN DSP-F manufactured by Wyatt Technology).

(Synthesis of star polymer)
Next, the synthesis of the star polymer of the example will be described. When synthesizing the star polymer of the example, first, 35 g of toluene, 0.1 g of acrylic acid, 1.03 g of t-butyl acrylate, 0.33 g of 9-BBN, p- Chloroaniline 0.34 g was added and heated in an oil bath at 80 ° C. for 300 minutes.

  Subsequently, 1.3 g of divinylbenzene and 1.07 g of ethylstyrene were added to the flask after heating for 300 minutes, and heated in an oil bath at 80 ° C. for 120 minutes. To the reaction mixture after heating, 100 g of methanol was added to reprecipitate the solid content, and the solid content obtained by reprecipitation was purified. As a result, the star polymer of Example 1 was obtained as a purified product. The yield of the star polymer of Example 1 was 1.2 g (35% yield). The weight average molecular weight by GPC was 13,000, and the absolute molecular weight by MALLS was 50,000.

(Example 2)
Polymerization was conducted in the same manner as in Example 1 except that 0.13 g of acrylic acid and 0.48 g of t-butyl acrylate were used. The yield of the star polymer of Example 2 was 1.0 g (34% yield). )Met. The weight average molecular weight by GPC was 13,000, and the absolute molecular weight by MALLS was 50,000.

(Example 3)
Polymerization was conducted in the same manner as in Example 1 except that 0.1 g of acrylic acid and 0.26 g of t-butyl acrylate were used. The yield of the star polymer of Example 3 was 0.96 g (35% yield). )Met. The weight average molecular weight by GPC was 11,000, and the absolute molecular weight by MALLS was 30,000.

Example 4
Polymerization was carried out in the same manner as in Example 1 except that 0.7 g of vinyl benzoic acid and 0.61 g of t-butyl vinyl benzoate were used. The yield of the star polymer of Example 4 was 1.5 g (yield 40%). The weight average molecular weight by GPC was 16,000, and the absolute molecular weight by MALLS was 62,000.

(Preparation of resist composition)
Preparation of the resist composition using the star polymer obtained in Examples 1 to 4 described above will be described. First, trace metals in the polymer are removed from the star polymers obtained in Examples 1 to 4 by the following method.

(Metal cleaning)
In the metal washing, a solution prepared by dissolving 6 g of the above-mentioned star polymer in 100 g of MIBK, 50 g of a 3% by mass oxalic acid aqueous solution, and 50 g of a 1% by mass hydrochloric acid aqueous solution were combined and vigorously stirred for 30 minutes. After stirring, the organic layer was taken out from the stirred solution, and 50 g of a 3% by mass oxalic acid aqueous solution and 50 g of a 1% by mass hydrochloric acid aqueous solution were again combined with the taken out organic layer and stirred vigorously for 30 minutes. After repeating this operation 5 times in total, the operation of combining the organic layer and 100 g of ultrapure water and stirring vigorously for 30 minutes was repeated 3 times. The solvent was distilled off from the finally obtained organic layer, and the amount of contained metal was measured by atomic absorption. As a result, the content of copper, sodium, iron, and aluminum in any polymer was 10 ppb or less.

(Preparation of resist composition)
The resist composition using the star polymer obtained in the above-described Examples 1 to 4 is 4.0% by mass of the star polymer from which trace metals have been removed, and 0% of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator. A propylene glycol monomethyl acetate (PEGMEA) solution containing .16% by mass was prepared by filtering with a filter having a pore diameter of 0.45 μm.

  The adjusted resist composition is spin-coated on a silicon wafer, and the silicon wafer coated with the adjusted resist composition is heat-treated at 90 ° C. for 1 minute to evaporate the solvent contained in the adjusted resist composition. Then, a thin film having a thickness of 100 nm was formed on the silicon wafer after evaporation of the solvent.

(UV irradiation sensitivity)
Next, the ultraviolet irradiation sensitivity of the thin film formed on the silicon wafer will be described. The ultraviolet irradiation sensitivity of the thin film formed on the silicon wafer was measured by the following method. When measuring the ultraviolet irradiation sensitivity, a discharge tube type ultraviolet irradiation device (manufactured by Ato Co., Ltd., DF-245 type DonaFix) was used as a light source.

In measuring the ultraviolet irradiation sensitivity, a sample thin film having a thickness of about 100 nm formed on a silicon wafer was irradiated with ultraviolet rays having a wavelength of 245 nm. The ultraviolet rays were applied to a rectangular portion of 10 mm long × 3 mm wide of the thin film formed on the silicon wafer. At the time of irradiation of ultraviolet rays, changing the amount of energy of ultraviolet light irradiated in the range from 0 mJ / cm ² of 50 mJ / cm ^2.

  The silicon wafer after ultraviolet irradiation was heat-treated at 100 ° C. for 4 minutes, and the silicon wafer after heat treatment was immersed in a 2.4% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) at 25 ° C. for 2 minutes. And developed. After development, the silicon wafer was washed with water and dried. The film thickness after drying was measured with a thin film measuring apparatus F20 manufactured by Filmetics Co., Ltd., and the irradiation energy value (sensitivity) at which the film thickness after development was zero was measured. The results are shown in Table 1.

  As shown above, it can be seen that the star polymer obtained according to the present invention exhibits good sensitivity.

Claims (6)

A method for synthesizing a star polymer by synthesizing a star polymer through living radical polymerization of monomers,
The arm part is synthesized by simultaneously polymerizing the monomer having an acid-decomposable group and the monomer having an acid group by the living radical polymerization, and an aromatic divinyl hydrocarbon is added to the arm part during or after the synthesis of the arm part. A method for synthesizing a star polymer, comprising adding a divinyl monomer. The copolymer is
2. The method for synthesizing a star polymer according to claim 1, wherein 9-borabicyclo [3.3.1] nonane is synthesized by living radical polymerization in an oxygen-existing atmosphere using an initiator as an initiator.   A star polymer synthesized according to the method for synthesizing a star polymer according to claim 1.   A resist composition comprising the star polymer according to claim 3.   A semiconductor integrated circuit, wherein a pattern is formed by the resist composition according to claim 4.   A method for producing a semiconductor integrated circuit, comprising a step of forming a pattern using the resist composition according to claim 5.