JPWO2008081894A1 - Synthesis method of core-shell hyperbranched polymer - Google Patents

Abstract

In order to synthesize a core-shell hyperbranched polymer that can be used as a polymer material for nanofabrication centering on optical lithography, when synthesizing a core-shell hyperbranched polymer via living radical polymerization of monomers, A shell containing living radical polymerization using an initiator monomer having a functional group that becomes a radical by ultraviolet rays, a polymer synthesized by living radical polymerization as a core, and an acid-decomposable group and an acid group at the end of the core The core-shell hyperbranched polymer was synthesized by forming the part.

Description

  The present invention relates to a method for synthesizing a core-shell hyperbranched 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 32 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 a KrF excimer laser beam (wavelength 248 nm), a polymer having a novolac-type polyphenol as a basic skeleton (see, for example, Patent Document 1 below), and in an ArF excimer laser beam (wavelength 193 nm), a poly (meth) acrylate ester (for example, , Refer to Patent Document 2 below), or F2 excimer laser light (wavelength 157 nm), each of which proposes a resist composition containing a polymer into which a fluorine atom (perfluoro structure) is introduced (for example, refer to Patent Document 3 below). These polymers are based on a linear structure.

  However, when these linear polymers are applied to the formation of ultrafine patterns having a thickness of 32 nm or less, the unevenness of the pattern side wall with the line edge roughness as an index has become 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 is 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 a hyperbranched polymer, an example using atom transfer radical polymerization is known (see, for example, WO 2005/061566 pamphlet). .), Atom transfer radical polymerization (ATRP method) is a reversible transfer reaction of an atom or group from a dormant species (RX) to a transition metal catalyst, thereby the radical that initiates polymerization, and the oxidation state. There is a problem that a large amount of metal halide must be removed from the reaction system after polymerization because it is based on a reaction in which one advanced metal halide is generated.

  In the ATRP method, when an acid-decomposable group and an acid group are to be introduced at the same time, a carboxylic acid group as an acid group is coordinated with copper as a catalyst, reducing the activity of the catalyst. First, an acid-decomposable group is introduced, and then a part of the acid-decomposable group is converted into an acid group by acid decomposition to synthesize a corresponding resist polymer.

  In high-performance photoresist polymers, the amount of metal impurities must be significantly reduced, especially to avoid contamination during plasma processing and adverse effects on semiconductor electrical properties due to metal impurities remaining in the pattern. Therefore, aggressive metal addition as a catalyst is not desirable. Further, in order to simplify the process, it is desirable that the acid-decomposable group and the acid group can be introduced simultaneously.

  The present invention has been made in view of the above circumstances, and can be used as a polymer material for nanofabrication centered on photolithography, a core-shell hyperbranched polymer with improved surface smoothness and alkali solubility, It is an object of the present invention to provide a method for producing the core-shell hyperbranched polymer and a resist composition containing the core-shell hyperbranched polymer.

  In order to solve the above-described problems and achieve the object, a method for synthesizing a core-shell hyperbranched polymer according to the present invention is a method for synthesizing a core-shell hyperbranched polymer by synthesizing a core-shell hyperbranched polymer through living radical polymerization of monomers. A polymerization step of performing the living radical polymerization using an initiator monomer having a functional group that becomes a radical by ultraviolet light, and a copolymer synthesized by the living radical polymerization as a core portion, And a shell part forming step of forming a shell part containing an acid-decomposable group and an acid group.

  According to this invention, since living radical polymerization can be performed without using a metal catalyst, synthesis of a hyperbranched polymer for resist can be realized by an easy treatment. Moreover, since living radical polymerization can be performed without using a metal catalyst, the reaction system is uniform and stable production is possible. Furthermore, since an acid-decomposable group and an acid group can be simultaneously introduced into the shell portion, the process can be simplified.

  Further, the polymerization step in the method of synthesizing the core-shell hyperbranched polymer according to the present invention includes the living step according to a radical reaction using a reversible addition fragmentation chain transfer (RAFT) method of a thiocarbonyl compound and a radical. It is characterized by radical polymerization.

  The core-shell hyperbranched polymer according to the present invention is characterized by being synthesized according to the above-described method for synthesizing a core-shell hyperbranched polymer.

  According to this invention, it is possible to obtain a core-shell hyperbranched polymer in which the reaction proceeds uniformly in the entire reaction system.

  The resist composition according to the present invention includes the core-shell hyperbranched polymer described above.

  According to this invention, a resist composition containing the core-shell hyperbranched polymer synthesized by the synthesis method described above can be obtained stably.

  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.

(Substance used for the synthesis of core-shell hyperbranched polymer)
First, substances used for synthesizing the core-shell hyperbranched polymer synthesized using the core-shell hyperbranched polymer synthesis method will be described. In the synthesis of the core-shell hyperbranched polymer, a vinyl monomer having a functional group serving as a starting species for living radical polymerization, other monomers, and a solvent are used.

(monomer)
First, a vinyl monomer having a functional group that is a starting species of living radical polymerization used for the synthesis of the core-shell hyperbranched polymer and other monomers will be described. When synthesizing a core-shell hyperbranched polymer, it is roughly classified into a vinyl monomer having a functional group that becomes a starting species of living radical polymerization for synthesizing a core portion and a monomer for synthesizing a shell portion.

<Vinyl monomer having a functional group that is a starting species for living radical polymerization>
First, among the monomers used for synthesizing the core part of the core-shell hyperbranched polymer (hereinafter referred to as hyperbranched core polymer), a vinyl monomer having a functional group serving as a starting species for living radical polymerization will be described. The vinyl monomer having a functional group serving as an initiating species for living radical polymerization is derived from a monomer represented by the following formula (I).

  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, an —OCH ₂ — group, and an —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, the monomer corresponding to the above formula (I) is preferably, for example, a chlorine atom or a bromine atom among the halogen atoms described above.

  Specific examples of the monomer represented by the above formula (I) include chloromethylstyrene, bromomethylstyrene, p- (1-chloroethyl) styrene, bromo (4-vinylphenyl) phenylmethane, 1-bromo- 1- (4-vinylphenyl) propan-2-one, 3-bromo-3- (4-vinylphenyl) propanol, and the like. Of these, chloromethylstyrene, bromomethylstyrene, and p- (1-chloroethyl) styrene are preferable.

  A vinyl monomer having a functional group serving as a starting species for living radical polymerization is synthesized by introducing an N, N-diethyldithiocarbamate group that starts living radical polymerization when irradiated with ultraviolet rays.

  The group that is introduced into the initiator monomer and starts living radical polymerization when irradiated with ultraviolet rays is not limited to the N, N-diethyldithiocarbamate group. Examples of the group that is introduced into the initiator monomer and starts living radical polymerization when irradiated with ultraviolet rays include N, N-dimethyldithiocarbamate groups introduced by sodium N, N-dimethyldithiocarbamyl and N , N-dihydroxyethyldithiocarbamate group, N, N-dimethylphenyldithiocarbamate group, N-methyl, N-ethyldithiocarbamate group, N-methyl, N-hydroxyethyldithiocarbamate group, N-methyl, N-methylphenyl Examples thereof include a dithiocarbamate group, N-ethyl, N-hydroxyethyldithiocarbamate group, N-ethyl, N-methylphenyldithiocarbamate group, N-hydroxyethyl, N-methylphenyldithiocarbamate group, and the like.

<Monomer constituting the core>
As a monomer constituting the hyperbranched core polymer of the present invention, other monomers can be included in addition to the vinyl monomer having a functional group serving as a starting species of the living radical polymerization. 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 (meth) acrylic acid esters mentioned as other monomers capable of radical polymerization include, for example, tert-butyl acrylate, 2-methylbutyl acrylate, 2-methylpentyl acrylate, and acrylic acid. 2-ethylbutyl, 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, acrylic acid 2 -Ethyl-2-adamantyl, acrylic acid 3 Hydroxy-1-adamantyl, tetrahydrofuranyl acrylate, tetrahydropyranyl acrylate, 1-methoxyethyl acrylate, 1-ethoxyethyl acrylate, 1-n-propoxyethyl acrylate, 1-isopropoxyethyl acrylate, acrylic acid n-butoxyethyl, 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 phosphate, dimethyl-tert-butylsilyl acrylate, α- (acryloyl) oxy-γ-butyrolactone, β- (acryloyl) oxy-γ-butyrolactone, γ- (acryloyl) oxy-γ-butyrolactone, α-methyl- α- (Acroyl) 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- (Acroyl) oxy-δ-valerolactone, γ- (acryloyl) oxy-δ-valerolacto , Δ- (acroyl) oxy-δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, β-methyl-β- (acroyl) 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- (Acroyl) oxy-δ-valerolactone, γ-ethyl-γ- (acryloyl) oxy-δ-valerolactone, δ-ethyl-δ- (acryloyl) oxy-δ-valerolactone, 1-methyl acrylate Cyclohexyl, adamantyl acrylate, 2- (2-methyl) adamantyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, a 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane acrylate, glycidyl acrylate, benzyl acrylate, phenyl acrylate, naphthyl acrylate, tert-butyl methacrylate, 2-methylbutyl methacrylate 2-methylpentyl methacrylate, 2-ethylbutyl methacrylate, 3-methylpentyl methacrylate, 2-methylhexyl methacrylate, 3-methylhexyl methacrylate, triethylcarbyl methacrylate, 1-methyl-1-cyclopentyl methacrylate 1-ethyl-1-cyclopentyl methacrylate, 1-methyl-1-cyclohexyl methacrylate, 1-ethyl-1-cyclohexyl methacrylate, 1-methylnorbornyl methacrylate, methacrylic acid -Ethyl norbornyl, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, tetrahydrofuranyl methacrylate, tetrahydropyranyl methacrylate, 1-methacrylic acid 1- Methoxyethyl, 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-amyloxyethyl methacrylate, 1-ethoxy-n-propyl methacrylate, 1-cyclohexyloxyethyl methacrylate, methoxypropyl methacrylate, Ethoxypropyl tacrylate, 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- (Methacroyl) oxy-γ-butyrolactone, γ-methyl-γ- (methacloyl) oxy-γ-butyrolactone, α-ethyl-α- (methacloyl) oxy-γ-butyrolactone, β-ethyl-β- (methacloyl) oxy- γ-butyrolactone, γ-ethyl γ- (methacryloyl) 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- (Methacloyl) oxy-δ-valerolactone, δ-methyl-δ- (methacloyl) oxy-δ-valerolactone, α-ethyl-α- (methacloyl) oxy-δ-valerolactone, β-ethyl-β- (methacloyl) ) Oxy-δ-valerolactone, γ-ethyl-γ- (methacloyl) oxy-δ-valerolactone, δ-ethyl-δ- ( Tacroyl) oxy-δ-valerolactone, 1-methylcyclohexyl methacrylate, adamantyl methacrylate, 2- (2-methyl) adamantyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2-dimethylhydroxy methacrylate Examples include propyl, 5-hydroxypentyl methacrylate, trimethylolpropane methacrylate, glycidyl methacrylate, benzyl methacrylate, phenyl methacrylate, naphthyl methacrylate, and the like.

  Specific examples of the vinyl benzoate esters mentioned as other monomers capable of radical polymerization include, for example, tert-butyl vinyl benzoate, 2-methylbutyl vinyl benzoate, 2-methylpentyl vinyl benzoate, and vinyl. 2-ethylbutyl benzoate, 3-methylpentyl vinylbenzoate, 2-methylhexyl vinylbenzoate, 3-methylhexyl vinylbenzoate, triethylcarbyl vinylbenzoate, 1-methyl-1-cyclopentyl vinylbenzoate, vinylbenzoate 1-ethyl-1-cyclopentyl acid, 1-methyl-1-cyclohexyl vinyl benzoate, 1-ethyl-1-cyclohexyl vinyl benzoate, 1-methylnorbornyl vinyl benzoate, 1-ethylnorbornyl vinyl benzoate, vinyl 2-methyl-2-adamanche benzoate , 2-ethyl-2-adamantyl vinyl benzoate, 3-hydroxy-1-adamantyl vinyl benzoate, tetrahydrofuranyl vinyl benzoate, tetrahydropyranyl vinyl benzoate, 1-methoxyethyl vinyl benzoate, 1-ethoxy vinyl benzoate Ethyl, 1-n-propoxyethyl vinylbenzoate, 1-isopropoxyethyl vinylbenzoate, n-butoxyethyl vinylbenzoate, 1-isobutoxyethyl vinylbenzoate, 1-sec-butoxyethyl vinylbenzoate, vinylbenzoate 1-tert-butoxyethyl acid, 1-tert-amyloxyethyl vinylbenzoate, 1-ethoxy-n-propyl vinylbenzoate, 1-cyclohexyloxyethyl vinylbenzoate, methoxypropyl vinylbenzoate, ethoxypropionate 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-vinyl Nzoyl) 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-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 1-methylcyclohexyl vinyl benzoate, adamantyl vinyl benzoate, 2- (2-methyl) adamantyl vinyl benzoate, chloroethyl vinyl benzoate, 2-hydroxyethyl vinyl benzoate, 2,2-dimethylhydroxypropyl vinyl benzoate, Examples thereof include 5-hydroxypentyl vinylbenzoate, trimethylolpropane vinylbenzoate, glycidyl vinylbenzoate, benzyl vinylbenzoate, phenyl vinylbenzoate, and naphthyl vinylbenzoate.

  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. It is done.

  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, and vinyl anthranyl ether.

  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 valate, vinyl caproate, Examples include vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinylphenylacetate, vinylacetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate and the like.

  Specific examples of the monomer used for the synthesis of the hyperbranched core polymer include (meth) acrylic acid, tert-butyl (meth) acrylate, 4-vinylbenzoic acid, tert-butyl 4-vinylbenzoate, and styrene. , Benzylstyrene, chlorostyrene, and vinylnaphthalene are preferred.

  The ratio of the repeating unit derived from the monomer constituting the hyperbranched core polymer is preferably 10 to 90 mol% with respect to all repeating units constituting the core-shell hyperbranched polymer. -80 mol% is more preferable, and it is still more preferable that it is contained in the amount of 10-60 mol%.

  By adjusting the amount of the repeating unit derived from the monomer constituting the hyperbranched core polymer to be within the above range, for example, when the core-shell hyperbranched polymer is used as a resist composition, Appropriate hydrophobicity can be imparted to the developer of the polymer. As a result, using a resist composition containing a core-shell hyperbranched polymer with a hyperbranched core polymer as a core part, for example, when performing microfabrication of semiconductor integrated circuits, flat panel displays, printed wiring boards, etc., unexposed Since dissolution of a part can be suppressed, it is preferable.

  The hyperbranched core polymer may be composed of only a vinyl monomer having a functional group that becomes the starting species of the living radical polymerization, or can be radically polymerized with a vinyl monomer having a functional group that becomes the starting species of the living radical polymerization. It may be composed of other monomers.

  When the hyperbranched core polymer is a copolymer of a vinyl monomer having a functional group that serves as an initiating species for the living radical polymerization and other monomers, the living unit is used for all the repeating units constituting the hyperbranched core polymer. The ratio of the repeating unit derived from the vinyl monomer having a functional group serving as a radical polymerization initiation species is preferably 10 to 99 mol%, more preferably 20 to 99 mol%, and more preferably 30 to 99 mol%. % Is even more preferable.

  In the hyperbranched core polymer, when the ratio of the repeating unit derived from the vinyl monomer having a functional group that becomes the starting species of the living radical polymerization is within the above range, the hyperbranched core polymer takes a spherical form, It is preferable because it is advantageous for suppressing the entanglement between the layers and functions such as an increase in substrate adhesion and a glass transition temperature. In addition, the quantity of the vinyl monomer which has a functional group used as the start seed | species of the said living radical polymerization in a core part, and another monomer can be adjusted with the preparation amount ratio at the time of superposition | polymerization according to the objective.

<Monomer constituting the shell part>
Next, of the monomers used for the synthesis of the core-shell hyperbranched polymer, the monomer that constitutes the shell portion will be described. The shell part of the core-shell hyperbranched polymer constitutes the end of the core-shell hyperbranched polymer molecule. The shell portion of the hyperbranched polymer includes at least one of repeating units represented by the following formulas (II) and (III).

  The repeating unit represented by the following formulas (II) and (III) generates 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. When the acid-decomposable group and the acid group are simultaneously introduced into the shell part, the ratio of the acid-decomposable group and the acid group in the shell part is the ratio of the repeating unit derived from other monomers constituting the core-shell hyperbranched polymer. Although the optimum value varies depending on, it is preferably 95/5 to 5/95. 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. Among these, as R ¹ in the above formula (II) and R ⁴ in the above formula (III), a hydrogen atom and a methyl group are preferable. 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 preferable 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 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 1-30.

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. As R ³ in the formula (II) and R ⁵ in the formula (III), a branched alkyl group having 1 to 20 carbon atoms is more preferable.

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 to 20, and more preferably 4 to 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 following formula (i) has a linear, branched, or cyclic structure. It is preferable that carbon number of the alkyl group in R < ⁶ > of group represented by following formula (i) is 1-10. The more preferable carbon number of the alkyl group in R < ⁶ > of group represented by following 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 from 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. R ⁷ and R ⁸ in the above formula (i) are preferably a branched alkyl group having 1 to 20 carbon atoms.

  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), the trialkylsilyl group includes carbon atoms 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.

  Examples of the monomer that gives the repeating unit represented by the above formula (II) include 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, vinyl benzoate 2- Tyl-2-adamantyl, 3-hydroxy-1-adamantyl vinylbenzoate, tetrahydrofuranyl vinylbenzoate, tetrahydropyranyl vinylbenzoate, 1-methoxyethyl vinylbenzoate, 1-ethoxyethyl vinylbenzoate, vinylbenzoic 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- Toxi-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- 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-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-vinylbenzoy ) Oxy-δ-valerolactone, γ-ethyl-γ- (4-vinylbenzoyl) oxy-δ-valerolactone, δ-ethyl-δ- (4-vinylbenzoyl) oxy-δ-valerolactone, vinylbenzoic acid 1 -Methylcyclohexyl, adamantyl vinyl benzoate, 2- (2-methyl) adamantyl vinyl benzoate, chloroethyl vinyl benzoate, 2-hydroxyethyl vinyl benzoate, 2,2-dimethylhydroxypropyl vinyl benzoate, 5-vinyl benzoate 5- Examples thereof include hydroxypentyl, 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-adamanche , 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-acrylate Cyclohexyloxyethyl, methoxypropyl acrylate, ethoxypropyl acrylate, 1-methoxy-1-methyl-ethyl acrylate, 1-ethoxy-1-methyl-ethyl acrylate, trimethylsilyl acrylate, triethylsilyl acrylate, acrylic Dimethyl tert-butylsilyl phosphate, 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- (acryloyl) oxy-δ-valerolactone, δ- (acryloyl) oxy δ-valerolactone, α-methyl-α- (4-vinylbenzoyl) oxy-δ-valerolactone, 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, acrylic acid 2 -(2-methyl) adamantyl, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2,2-dimethyl acrylate Roxypropyl, 5-hydroxypentyl acrylate, trimethylolpropane acrylate, glycidyl acrylate, benzyl acrylate, phenyl acrylate, naphthyl acrylate, methacrylic acid, tert-butyl methacrylate, 2-methylbutyl methacrylate, 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 -Ethyl-1-cyclopentyl, 1-methyl-1-cyclohexyl methacrylate, 1-ethyl-1-cyclohexyl methacrylate, 1-methylnorbornyl methacrylate, 1-ethylnor methacrylate Nyl, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, 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, methacrylic acid 1-tert-butoxyethyl, 1-tert-amyloxyethyl methacrylate, 1-ethoxy-n-propyl methacrylate, 1-cyclohexyloxyethyl methacrylate, methoxypropyl methacrylate, ethyl methacrylate Xylpropyl, 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- (methac Yl) 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- (methacloyl) oxy-δ-valerolactone, α-ethyl-α- (methacloyl) oxy-δ-valerolactone, β-ethyl-β- (methacloyl) oxy- δ-valerolactone, γ-ethyl-γ- (methacloyl) oxy-δ-valerolactone, δ-ethyl-δ- (methacloyl) Xyl-δ-valerolactone, 1-methylcyclohexyl methacrylate, adamantyl methacrylate, 2- (2-methyl) adamantyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2-dimethylhydroxypropyl methacrylate, Examples include 5-hydroxypentyl methacrylate, 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 a shell part, the copolymer of at least one of 4-vinyl benzoic acid or acrylic acid and at least one of 4-vinyl benzoate tert-butyl or tert-butyl acrylate is also preferable. The monomer constituting the shell 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 the styrenes listed as copolymerizable monomers that can be used as the monomer constituting the shell 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 the allyl esters listed as copolymerizable monomers that can be used as the monomer constituting the shell 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 vinyl ethers listed as copolymerizable monomers that can be used as the monomer constituting the shell portion include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl 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 Tolyl ether, vinyl chlorophenyl ether, vinyl 2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether, and the like.

  Specific examples of the vinyl ester that can be used as a monomer constituting the shell portion include, for example, vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl 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 listed as copolymerizable monomers that can be used as the monomer constituting the shell 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 shell portion include the following formulas (IV) to (XIII).

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

  In the core-shell hyperbranched polymer, the monomer giving the repeating unit represented by at least one of the above formula (II) or the above formula (III) is charged relative to the total amount of monomers used for the synthesis of the core-shell hyperbranched polymer. In some cases, it is preferably contained in the range of 10 to 90 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 core-shell hyperbranched 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 total amount of the monomer used for the synthesis of the core-shell hyperbranched polymer. In particular, the repeating unit represented by the above formula (II) or the above formula (III) in the shell portion is 50 to 100 mol% at the time of charging with respect to the total amount of monomers used for the synthesis of the core-shell hyperbranched polymer. , Preferably in the range of 80 to 100 mol%.

  A resist composition containing the hyperbranched polymer when the monomer giving the repeating unit is within the aforementioned range at the time of charging with respect to the charged amount of the whole monomer used for the synthesis of the core-shell hyperbranched polymer. In the lithographic development process using, it is preferable because the exposed portion is efficiently dissolved and removed in the alkaline solution.

  When the shell part of the core-shell hyperbranched polymer is a copolymer of a monomer that gives a repeating unit represented by the above formula (II) or the above formula (III) and another monomer, all the monomers that form the shell part The amount of at least one of the above formula (II) or 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 shell portion is within the above-mentioned range, the etching resistance is not impaired without inhibiting the effective alkali solubility of the exposed portion. It is preferable because functions such as wettability and glass transition temperature are increased.

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

(solvent)
Next, the solvent used for the synthesis of the core-shell hyperbranched polymer will be described. The polymerization reaction of the core-shell hyperbranched polymer can be carried out without a solvent, but it is preferable to carry out the polymerization in various solvents shown below. The type of solvent used for the synthesis of the core-shell hyperbranched polymer is not particularly limited. For example, hydrocarbon solvents, ether solvents, halogenated hydrocarbon solvents, ketone solvents, alcohol solvents, nitrile solvents, Examples include ester solvents, carbonate solvents, amide solvents, and the like.

  Specific examples of the hydrocarbon solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include benzene and toluene. Specific examples of the ether solvent that is a solvent used in the synthesis of the hyperbranched polymer include diethyl ether, tetrahydrofuran, diphenyl ether, anisole, and dimethoxybenzene.

  Specific examples of the halogenated hydrocarbon solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include methylene chloride, chloroform, chlorobenzene, and the like. Specific examples of the ketone solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Specific examples of the alcohol solvent that is used for the synthesis of the core-shell hyperbranched polymer include methanol, ethanol, propanol, and isopropanol.

  Specific examples of the nitrile solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include acetonitrile, propionitrile, benzonitrile, and the like. Specific examples of the ester solvent that is a solvent used in the synthesis of the hyperbranched polymer include ethyl acetate and butyl acetate. Specific examples of the carbonate solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include ethylene carbonate and propylene carbonate.

  Specific examples of the amide solvent that is a solvent used for the synthesis of the core-shell hyperbranched polymer include N, N-dimethylformamide and N, N-dimethylacetamide. The various solvents described above as the solvent used for the synthesis of the core-shell hyperbranched polymer may be used alone or in combination of two or more.

(Synthesis process of core-shell hyperbranched polymer)
Next, a method for synthesizing the core-shell hyperbranched polymer will be described. In polymerization, for example, the reaction system is uniformly dispersed by stirring the reaction system. As specific stirring conditions for the polymerization, for example, the required power for stirring per unit volume is preferably 0.01 kW / m ³ or more.

  In the core polymerization, the concentration of the monomer is preferably 1 to 50% by mass with respect to the total amount of the reaction. A more preferable monomer concentration is 3 to 20% by mass with respect to the total amount of the reaction. Living radical polymerization is carried out for 0.5 to 100 hours with the reaction system kept at 20 to 150 ° C.

  In the core polymerization, a monomer (charged monomer) can be added later to a reaction vessel in which a polymerization reaction is performed to cause the reaction. Here, the mixing amount (addition amount) of the monomer per time with respect to the reaction vessel (reaction system) is set to be less than the total amount of monomers mixed in the reaction system.

  For example, by adding a monomer in a reaction system by dropping the monomer over a predetermined time, or by adding a constant amount of monomer that is divided into a plurality of times to the total amount of monomer mixed in the reaction system at regular intervals. Mixing the monomer into the reaction system according to the splitting system that mixes the monomer into the reaction system, etc., mixes the amount of monomer added (added) per reaction vessel (reaction system) to the reaction system. Less than the total amount of monomers to be treated.

  Further, for example, the monomer may be mixed into the reaction system by continuously dropping the monomer over a predetermined time. In this case, the mixing amount (addition amount) of the monomer mixed within a certain unit time with respect to the reaction system is less than the total amount of monomers mixed into the reaction system.

  When the monomer is mixed into the reaction system using a continuous system, the monomer dropping time is preferably, for example, 5 to 300 minutes. The more preferable dropping time of the monomer when mixing the monomer into the reaction system using a continuous system is 15 to 240 minutes. A more preferable dropping time in the case of mixing the monomer into the reaction system using a continuous system is 30 to 180 minutes.

  When mixing a monomer into a reaction system using a dividing formula, a single monomer is mixed and then a predetermined interval is opened to mix the next monomer. The predetermined time may be, for example, the time required for the mixed monomer to perform at least one polymerization reaction, or may be the time required for the mixed monomer to be uniformly dispersed throughout the reaction system. Alternatively, it may be the time required for the temperature of the reaction system changed by mixing the monomers to become stable.

  In addition, when the dripping time of the monomer with respect to the reaction system is too short, there is a possibility that a sufficient effect for suppressing a rapid increase in molecular weight may not be exhibited. In addition, if the dropping time of the monomer to the reaction system is too long, the total polymerization time from the start to the end of the synthesis of the hyperbranched core polymer becomes longer, which may increase the cost of synthesizing the hyperbranched core polymer. This is not preferable.

  After core polymerization, the hyperbranched core polymer synthesized by core polymerization is mixed with the monomer constituting the shell portion described above to perform shell polymerization. As a result, a core-shell hyperbranched polymer having the core synthesized by the core polymerization and the shell synthesized by the shell polymerization is synthesized.

  The concentration of the monomer in the shell polymerization is preferably 0.5 to 200 molar equivalents relative to the reactive site of the hyperbranched core polymer. The more preferable monomer concentration in the shell polymerization is 1 to 150 molar equivalents relative to the reactive site of the hyperbranched core polymer. The core / shell ratio can be controlled by appropriately controlling the monomer amount with respect to the reactive site of the hyperbranched core polymer.

  The polymerization time for shell polymerization is preferably 0.1 to 300 hours depending on the molecular weight of the polymer.

  Thereafter, the synthesized core-shell hyperbranched polymer is purified. In purifying the synthesized core-shell hyperbranched polymer, unreacted monomers after shell polymerization are removed. Before shell polymerization, unreacted monomers after core polymerization may be removed and then shell polymerization may be performed to remove unreacted monomers after shell polymerization.

As a method for removing unreacted monomers, for example, the following methods (S-1) to (S-2) can be carried out singly or in combination.
(S-1) The polymer is precipitated by adding a poor solvent to the reactant dissolved in the good solvent.
(S-2) The polymer is washed with a mixed solvent of a good solvent and a poor solvent.

  In the above (S-1) to (S-2), examples of the good solvent include halogenated hydrocarbons, nitro compounds, nitriles, ethers, ketones, esters, carbonates, and mixed solvents containing these. . Specific examples include tetrahydrofuran, chlorobenzene, chloroform, and the like. Examples of the poor solvent include methanol, ethanol, 1-propanol, 2-propanol, water, or a solvent obtained by combining these solvents. The method for removing the unreacted monomer is not particularly limited to the method described above.

(Molecular structure)
Next, the molecular structure of the core-shell hyperbranched polymer described above will be described. The branching degree (Br) of the core part in the core-shell hyperbranched polymer is preferably 0.3 to 0.5. A more preferable degree of branching (Br) is 0.4 to 0.5. When the degree of branching (Br) of the core portion in the hyperbranched polymer is in the above range, it is preferable because entanglement between polymer molecules is small and surface roughness on the pattern side wall is suppressed.

Here, the branching degree (Br) of the core part in the core-shell hyperbranched polymer can be determined as follows by measuring ¹ H-NMR of the product. That is, it can be calculated by calculating the following formula (A) using the proton integration ratio H1 ° of the —CH ₂ S site proton and the proton integration ratio H2 ° of the —CHS site. When polymerization proceeds at both the —CH ₂ S site and the —CHS site and branching increases, the value of the degree of branching (Br) approaches 0.5.

  The weight average molecular weight (Mw) of the core part in the core-shell hyperbranched polymer is preferably 300 to 10,000, more preferably 500 to 10,000, and 1,000 to 10,000. Is most preferred. When the molecular weight of the core part is in such a range, the core part takes a spherical shape and is preferable because solubility in a reaction solvent can be secured in the acid-decomposable group introduction reaction. Further, it is preferable in the hyperbranched polymer having excellent film forming property and having an acid-decomposable group derived in the core part in the above molecular weight range because it is advantageous for inhibiting dissolution of the unexposed part.

  The polydispersity (Mw / Mn) of the core portion in the core-shell hyperbranched 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 weight average molecular weight (M) of the core-shell hyperbranched polymer is preferably 500 to 50,000, more preferably 2,000 to 50,000, and most preferably 3,000 to 50,000. When the weight average molecular weight (M) of the core-shell hyperbranched polymer is in such a range, the resist containing the hyperbranched polymer has good film formability, and the strength of the processing pattern formed in the lithography process is high. Therefore, the shape can be maintained. It also has excellent dry etching resistance and good surface roughness.

  Here, the weight average molecular weight (Mw) of the core part in the core-shell hyperbranched polymer is obtained, for example, by preparing a 0.5 mass% tetrahydrofuran solution and performing GPC (Gel Permeation Chromatography) measurement at a temperature of 40 ° C. Can do. In the measurement, tetrahydrofuran is used as a mobile solvent, polystyrene is used as a standard substance, and two TSKgel HXL-M (manufactured by Tosoh Corporation) are connected to a column using a GPC HLC-8020 type apparatus.

For the weight average molecular weight (M) of the core-shell hyperbranched polymer, the introduction ratio (configuration ratio) of each repeating unit of the polymer into which the acid-decomposable group was introduced was determined by ¹ H-NMR. Based on the weight average molecular weight (Mw) of the portion, it can be obtained by calculation using the introduction ratio of each structural unit and the molecular weight of each structural unit. The shape of the synthesized core-shell hyperbranched polymer can be judged to be spherical from the primary and secondary hydrogens by NMR.

  As described above, according to the embodiment, since living radical polymerization can be performed without using a metal catalyst, synthesis of a hyperbranched polymer for resist can be realized by easy processing. Moreover, according to the embodiment, since living radical polymerization can be performed without using a metal catalyst, the reaction system is uniform and stable production is possible.

  Moreover, according to the resist composition containing such a core-shell hyperbranched polymer, the photoresist can be subjected to patterning by developing after being exposed in a pattern.

  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 core-shell hyperbranched polymer produced using the production method according to the present invention is suitable in various fields using a semiconductor integrated circuit produced using a light source that emits light having a short wavelength. Can be used.

  Further, in the semiconductor integrated circuit manufactured using the resist composition containing the hyperbranched polymer of the embodiment, when it is exposed and heated during manufacturing, dissolved in an alkali developer, and then washed by washing, There is almost no unmelted residue on the exposed 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, the above-described embodiment according to the present invention will be specifically clarified by using the following examples. In addition, this invention is not limited at all by the Example shown below.

(Synthesis of N, N-diethyldithiocarbamylmethylstyrene)
N, N-diethyldithiocarbamylmethylstyrene was synthesized by reacting chloromethylstyrene with sodium N, N-diethyldithiocarbamyl according to a method described in a known document (Macromolecules 2002, 35, 3781).

Example 1
67 g of benzene and 10 g of N, N-diethyldithiocarbamylmethylstyrene were placed in a 500 mL flask equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, and nitrogen gas was introduced from the nitrogen inlet tube while stirring. Thereafter, a 120 W high-pressure mercury lamp (Sen Special Light Source Co., Ltd., HB-101) equipped with a cooling jacket was irradiated with water at a distance of 5 cm for 48 hours.

  Subsequently, 133 g of benzene, 3.3 g of acrylic acid, and 25.8 g of t-butyl acrylate were added to the solution after irradiation with the high pressure mercury lamp, and a 120 W high pressure mercury lamp equipped with a cooling jacket (Sen Special Light Source Co., Ltd., HB-101) was irradiated for 200 hours at a distance of 5 cm while cooling with water. To the solution after irradiation with a high-pressure mercury lamp, 2000 mL of ultrapure water was added to the reaction mixture to cause reprecipitation, and the core-shell hyperbranched polymer of the example was obtained as a purified product. The yield of the core-shell hyperbranched polymer of Example 1 was 15.9 g (yield 40%), and the weight average molecular weight was 6,000. The degree of branching (Br) was 0.35.

(Example 2)
Polymerization was conducted in the same manner as in Example 1 except that 4.1 g of acrylic acid and 12.0 g of t-butyl acrylate were used, and the yield of the core-shell hyperbranched polymer of Example 2 was 11.0 g (yield 41%). The weight average molecular weight was 6,000. The degree of branching (Br) was 0.35.

(Example 3)
Polymerization was conducted in the same manner as in Example 1 except that 4.1 g of acrylic acid and 5.7 g of t-butyl acrylate were used, and the yield of the core-shell hyperbranched polymer of Example 3 was 8.7 g (yield 42%). The weight average molecular weight was 6,000. The degree of branching (Br) was 0.35.

Example 4
Polymerization was carried out in the same manner as in Example 1 except that 11.0 g of vinyl benzoic acid and 15.2 g of t-butyl vinyl benzoate were used, and the yield of the core-shell hyperbranched polymer of Example 4 was 8.2 g ( Yield 45%). The weight average molecular weight was 6,000. The degree of branching (Br) was 0.38.

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

(Metal cleaning)
In metal washing, a solution prepared by dissolving 6 g of the core-shell hyperbranched polymer described above in 100 g of methyl isobutyl ketone was combined with 50 g of a 3% by mass oxalic acid aqueous solution and 50 g of a 1% by mass hydrochloric acid aqueous solution, 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 hyperbranched polymer obtained in Examples 1 to 4 described above is 4.0% by mass of the hyperbranched polymer from which trace metals are removed, and triphenylsulfonium trifluoromethanesulfonate as a photoacid generator. Was prepared by filtering a propylene glycol monomethyl acetate (PEGMEA) solution containing 0.16% by mass 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 core-shell hyperbranched polymer obtained by the present invention exhibits good sensitivity.

Claims (6)

A core-shell hyperbranched polymer synthesis method for synthesizing a core-shell hyperbranched polymer via a living radical polymerization of monomers,
A polymerization step of performing the living radical polymerization using an initiator monomer having a functional group that becomes a radical by ultraviolet rays;
A shell part forming step in which a copolymer synthesized by the living radical polymerization is used as a core part, and a shell part including an acid-decomposable group and an acid group is formed at an end of the core part;
A method for synthesizing a core-shell hyperbranched polymer, comprising: The polymerization step includes
The method for synthesizing a core-shell hyperbranched polymer according to claim 1, wherein the living radical polymerization is performed according to a radical reaction utilizing a cross-chain reaction between a thiocarbonyl compound and a radical.   A core-shell hyperbranched polymer characterized by being synthesized according to the method for synthesizing a core-shell hyperbranched polymer according to claim 1 or 2.   A resist composition comprising the core-shell hyperbranched 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 4.