JP4689216B2 - Alkenylphenol star polymer - Google Patents

Description

  The present invention relates to an alkenylphenol-based star polymer, and more particularly to a star polymer including a repeating unit derived from an acrylate derivative as a core portion and a repeating unit derived from an alkenylphenol derivative as an arm portion.

  Alkenylphenol homopolymers and copolymers represented by poly-p-hydroxystyrene are useful as chemically amplified excimer laser resist materials. Among them, acrylic ester or methacrylic ester [hereinafter referred to as “(meth) acrylic ester” A resist using a copolymer having t-butyl (meth) acrylate as a comonomer is known as a so-called ESCAP type resist capable of high resolution. And as a copolymer of p-hydroxystyrene and t-butyl (meth) acrylate, those obtained by thermal polymerization of a vinylphenol monomer and t-butyl (meth) acrylate, p-acetoxystyrene and t- A product obtained by copolymerizing butyl (meth) acrylate with a radical polymerization method and then selectively hydrolyzing only an acetoxy group using a small amount of an acidic reagent or an alkaline reagent is already commercially available.

  As for the alkenylphenol-based star polymer, for example, JP-A-2002-226513 discloses a star polymer having a p-hydroxystyrene-styrene copolymer or a p-hydroxystyrene-butadiene copolymer as an arm part. The core part was a divinylbenzene polymer in all synthesis examples.

On the other hand, as a star polymer having a core part other than divinylbenzene polymer, a polymer chain obtained by anionic polymerization of methyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate is dicumyl alcohol dimethacrylate, or 2,5- A synthesis example of a star-type polymer obtained by reacting dimethyl-2,5-hexanediol dimethacrylate has been reported (see Non-Patent Document 1). However, a star polymer having a hydroxystyrene skeleton in the arm portion and having a core portion made of an acrylic acid derivative has not been known so far.
JP 2002-226513 A L. Kilian et al. Polymer Science, Part A, 2003, p. 3083.

  An object of the present invention is to provide an alkenylphenol-based star polymer having preferable characteristics for a resist material. Another object of the present invention is to provide a method for synthesizing the star polymer which is a novel polymer compound. Still another object of the present invention is to provide a resist composition containing the star polymer.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a polymer of an acrylic acid derivative in the core portion, and the present invention has been completed.

That is, according to one aspect of the present invention, a star polymer including a core portion as a central core and an arm portion as a polymer chain connected to the central core,
The arm portion has the formula (I):

[Wherein R ¹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, R ² is a halogen atom or a C ₁ -C ₁₂ hydrocarbon group, R ³ is a hydrogen atom or a protecting group, and m is An integer of 0 to 4, R ² may be the same or different when m is 2 or more, n is 1 or 2, and when n is 2, R ³ may be the same or different , M + n is an integer from 1 to 5]
A polymer chain comprising a repeating unit derived from an alkenylphenol derivative represented by:
The core part has the formula (II):

[Wherein, R ⁴ and R ⁵ are a hydrogen atom or a C ₁ -C ₄ alkyl group, R ⁶ is a divalent or higher-valent hydrocarbon group having 2 or more carbon atoms that does not contain a quaternary carbon atom, and x Is an integer of 1 or more, and when x is 2 or more, R ⁴ may be the same or different.
The star polymer is provided which is a polymer derived from an acrylate derivative represented by:

According to another aspect of the present invention, the arm portion is a repeating unit derived from an alkenylphenol derivative represented by the above formula (I); and the formula (III):

[Wherein R ⁷ represents a hydrogen atom or a C ₁ -C ₄ alkyl group, R ⁸ represents a halogen atom or an organic group, and y represents an integer of 0 to 5]
A repeating unit derived from a styrene derivative represented by formula (IV):

[Wherein R ⁹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, and R ¹⁰ is a hydrogen atom or an organic group]
A star polymer which is a polymer chain of a copolymer having a repeating unit derived from an acrylate derivative represented by the formula: In one embodiment of the invention, the arm of the star polymer of the invention is derived from a polymer chain consisting of repeating units derived from an alkenylphenol derivative of formula (I), or from an alkenylphenol derivative of formula (I). And a polymer chain of a copolymer comprising a repeating unit derived from an acrylate derivative of the formula (IV). In yet another embodiment, the arm portion is composed of a repeating unit derived from an acrylate derivative of formula (IV) bonded to the core portion and a repeating unit derived from an alkenylphenol derivative of formula (I) bonded to the terminal thereof. This is a polymer chain of a block copolymer.

In one embodiment, x in the formula (II) is 1, R ⁶ is a — (CHR ¹¹ ) _p — group, p is an integer of 2 to 6, and each R ¹¹ is independently is a hydrogen atom or an alkyl group C ₁ -C _4. In addition, R ¹⁰ in formula (IV) may be a hydrogen atom, an organic group having an alicyclic skeleton, an organic group having a lactone ring, or a C _{1 to} C ₁₂ alkyl group.

  In the star polymer of the present invention, the number average molecular weight is, for example, 1,000 to 1,000,000, and the molecular weight dispersity (weight average molecular weight / number average molecular weight) is, for example, 1.01 to 3.00. It is. The composition ratio of the polymer in the core part and the polymer chain in the arm part (core part / arm part) is, for example, 1/1000 to 1 / 0.1.

According to still another aspect of the present invention, a resist composition containing the above star polymer is also provided.
According to yet another aspect of the invention:
a) a step of obtaining a polymer chain by polymerizing the alkenylphenol derivative represented by the above formula (I); and b) a step of copolymerizing the polymer chain with an acrylate derivative represented by the above formula (II);
In the case where R ³ in formula (I) is a protecting group, there is also provided a method for producing the star polymer of the present invention, which may further comprise the step of removing the protecting group.

According to yet another aspect of the invention:
a) obtaining a polymer chain by polymerizing the alkenylphenol derivative represented by formula (I) according to claim 1;
b) polymerizing the polymer chain with the styrene derivative represented by formula (III) or the acrylate derivative represented by formula (IV) according to claim 2 to obtain a copolymer; and c) the copolymer Copolymerizing the polymer with an acrylate derivative represented by formula (II) according to claim 1;
In the case where R ³ in formula (I) is a protecting group, there is also provided a method for producing the star polymer of the present invention, which may further comprise the step of removing the protecting group.

  The core portion constituting the star polymer of the present invention is a polymer derived from a polyacrylate represented by the formula (II). In addition, when described as acrylate, both acrylic ester and methacrylic ester are included.

In formula (I), R ¹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, preferably a hydrogen atom or a methyl group. R ² is a halogen atom or a C _{1 to} C ₁₂ hydrocarbon group. Here, the hydrocarbon group means a functional group consisting of a carbon atom and a hydrogen atom. For example, a methyl group, an ethyl group, a -propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an s-butyl group, Isobutyl group, n-pentyl group, s-pentyl group, isopentyl group, neopentyl group, n-hexyl group, s-hexyl group, 1,1-dimethyl-n-hexyl group, n-heptyl group, n-decyl group, n- dodecyl group C _l -C ₂₀ alkyl group such as a vinyl group, an allyl group, a 2-butenyl group, 1-methyl-2-propenyl group, 4-alkynyl group C ₂ -C _20, such as octenyl group, ethynyl group, propargyl group, 1-methylcyclohexyl alkynyl group C ₂ -C _20, such as a propynyl group, a cyclopropyl group, cyclobutyl group, cyclopentyl group, 1-methylcyclopentyl group, 1-methyl C ₃ -C ₂₀ alicyclic hydrocarbon group such as cyclohexyl group, 1-adamantyl group, 1-methyladamantyl group, 2-adamantyl group, 2-methyl-2-adamantyl group, norbornyl group, phenyl group, 1- naphthyl group, and the like aromatic hydrocarbon radical of C ₆ -C _20, such as 9-anthracenyl group.

In the formula (I), R ³ is a hydrogen atom or a protecting group. Here, the protecting group is not particularly limited as long as it is a group known in the technical field that it can be used as a protecting group for a phenolic hydroxyl group. Examples of the protecting group include a methoxymethyl group, a 2-methoxyethoxymethyl group, a bis (2-chloroethoxy) methyl group, a tetrahydropyranyl group, a 4-methoxytetrahydropyranyl group, a tetrahydrofuranyl group, and a triphenylmethyl group. , Trimethylsilyl group, 2- (trimethylsilyl) ethoxymethyl group, t-butyldimethylsilyl group, trimethylsilylmethyl group, or a substituent represented by the following formula.

(Wherein k represents 0 or 1). In addition, the following formula:

Wherein R ³¹ represents a C ₁ -C ₂₀ unsubstituted or alkoxy substituted alkyl group, a C ₅ -C ₁₀ cycloalkyl group, or a C ₆ -C ₂₀ unsubstituted or alkoxy substituted aryl group, R ³² represents hydrogen or a C _{1 to} C ₃ alkyl group, and R ³³ represents hydrogen, a C _{1 to} C ₆ alkyl group, or a C _{1 to} C ₆ alkoxy group. Specific examples of such substituents include 1-methoxyethyl group, 1-ethoxyethyl group, 1-methoxypropyl group, 1-methyl-1-methoxyethyl group, 1- (isopropoxy group). ) An ethyl group etc. can be illustrated.

  The repeating unit derived from the alkenylphenol derivative represented by the formula (I) has the following formula (Ia):

[Wherein R ¹ , R ² , R ³ , m and n are as defined above]
Means a repeating unit represented by
In formula (II), R ⁴ and R ⁵ are a hydrogen atom or a C ₁ -C ₄ alkyl group, preferably a hydrogen atom or a methyl group. R ⁶ is a divalent or higher divalent hydrocarbon group having 2 or more carbon atoms and not containing a quaternary carbon atom, preferably a divalent or higher divalent hydrocarbon group having 2 to 20 carbon atoms and not containing a quaternary carbon atom. x is an integer greater than or equal to 1, Preferably it is an integer of 1-6. When x is an integer of 1 to 6, R ⁶ is a 2 to 7 valent hydrocarbon group. Preferable examples of R ⁶ include an alkylene group, a phenylene group, an alkylene group containing a phenylene group, and the like, and a group — (CHR ¹¹ ) _p — (wherein p is an integer of 2 to 6, and R ¹¹ is a hydrogen atom or an alkyl group of C ₁ -C ₄₎ are also included. Particularly preferred examples of R ⁶ include ethylene, propylene, butylene, phenylene, cyclohexylene and the like, and ethylene is particularly preferred. The “quaternary carbon atom” in the present specification means a carbon atom bonded to four carbon atoms, as is generally understood by those skilled in the art.

  Specific examples of the acrylate derivative represented by the formula (II) include the following compounds.

In formula (III), R ⁷ is a hydrogen atom or a C ₁ -C ₄ alkyl group, preferably a hydrogen atom or a methyl group. R ⁸ is a halogen atom or an organic group. Here, the organic group is a generic name for functional groups having at least one carbon atom, such as alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aryl groups, aralkyl groups, alkoxy groups, alkylamino groups, dialkylamino groups. Group etc. are included. Preferred examples of R ⁸ include an alkyl group. y is preferably 0.

  The repeating unit derived from the styrene derivative represented by the formula (III) has the following formula (IIIa):

[Wherein R ⁷ , R ⁸ and y are as defined above]
Means a repeating unit represented by
In formula (IV), R ⁹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, preferably a hydrogen atom or a methyl group, and R ¹⁰ is an organic group. The repeating unit derived from the acrylate derivative represented by the formula (IV) has the following formula (IVa):

[Wherein R ⁹ and R ¹⁰ are as defined above]
Means a repeating unit represented by Here, the organic group is a generic name for functional groups having at least one carbon atom, and preferred examples include organic groups having an alicyclic hydrocarbon skeleton and organic groups having a lactone ring.

As an organic group having an alicyclic hydrocarbon skeleton, the following formula (V):
-AB (V)
In the formula, A represents a single bond, —O—, —COO—, —OCO—, —CO—, an alkylene group, or a divalent combination thereof. And B represents any of the following formulas (V-1) to (V-6):

[In the above formulas (V-1) to (V-6), R ¹¹¹ represents a hydrogen atom or a C _{1 to} C ₅ alkyl group, and Z together with the carbon atom forms an alicyclic hydrocarbon group. R ^{112 to} R ¹¹⁶ are each independently a hydrogen atom, a C _{1 to} C ₄ alkyl group or an alicyclic hydrocarbon group, provided that at least one of R ^{112 to} R ¹¹⁴ And R ¹¹⁵ or R ¹¹⁶ is an alicyclic hydrocarbon group, and R ^{117 to} R ¹²¹ are each independently a hydrogen atom, a C _{1 to} C ₄ alkyl group, or an alicyclic hydrocarbon group. Yes, but at least one of R ^{117 to} R ¹²¹ is an alicyclic hydrocarbon group, and either R ¹¹⁹ or R ¹²¹ is a C _{1 to} C ₄ alkyl group or an alicyclic hydrocarbon group, and R ¹²² to R ¹²⁵ are each independently a hydrogen atom, a linear or may have a branched chain C ₁ -C ₄ alkyl group, Others are an alicyclic hydrocarbon group, provided that at least one of R ¹²² to R ¹²⁵ is an alicyclic hydrocarbon group.

  Specific examples of the alicyclic hydrocarbon group include skeletons represented by the following formula:

  In particular, a 2-substituted adamantyl group represented by the following formula (VI) can be preferably exemplified.

Wherein (VI), R ¹³⁰ is a hydrogen atom or an optionally substituted alkyl group, in each of R ¹³¹ to R ¹³³ independently, a hydroxyl group, a halogen atom, a carboxyl group, C ₁ -C ₆ alkyl Group, C ₃ -C ₈ cycloalkyl group, C ₂ -C ₇ alkenyl group, alkoxy group, alkoxycarbonyl group, and acyl group, p, q, and r are each independently an integer of 0 and 1-3 And when p, q, or r is 2 or more, R ^{131 s} , R ^{132 s} , and R ^{133 s} may be the same or different from each other.

  A specific example of A is a divalent group represented by the following formula:

[In the above formula, Ra and Rb each independently represent a hydrogen atom, a C ₁ -C ₆ alkyl group, a substituted C ₁ -C ₆ alkyl group, a halogen atom, a hydroxyl group, a C ₁ -C ₆ alkoxy group; Preferred examples include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. The substituent of the substituted C ₁ -C ₆ alkyl group, a hydroxyl group, a halogen atom, can be mentioned C ₁ -C ₆ alkoxy group, and the C ₁ -C ₆ alkoxy group, a methoxy group, an ethoxy group, a propoxy group And C ₁ -C ₄ alkoxy groups such as a butoxy group. As a halogen atom, a chlorine atom, a bromine atom, a fluorine atom, an iodine atom, etc. can be illustrated. r1 is selected from an integer of 1 to 10, and m is selected from an integer of 1 to 3.

Examples of the acrylate derivative of the formula (IV) in which R ¹⁰ is an alicyclic hydrocarbon group include compounds represented by the following formula.

Specific examples of the acrylate having an organic group having a lactone ring include butyrolactone acrylate, butyrolactone methacrylate, mevalonic lactone methacrylate, pantolactone methacrylate, and the like. The organic compound represented by the following formula (VII) The group can be preferably exemplified.
-AC (VII)
In the formula, A represents the same meaning as the divalent group described above, and C represents any one of the following formulas (VIII-1) to (VIII-5):

[In the formulas (VIII-1) to (VIII-5), X represents an oxygen atom, a sulfur atom or an alkylene group which may have a substituent, and ^R201 may have a substituent. good C ₁ -C ₆ alkyl group, a C ₃ -C ₈ cycloalkyl group, or C ₂ -C ₇ alkenyl group,, m1 is selected from integers of 0 and 1 to 5; when m1 is 2 or more, R ²⁰¹ may be the same or different from each other, and may be bonded to each other to form a ring.

  Specific examples of the acrylate having a lactone ring include compounds represented by the following formulae.

The arm part of the star polymer of the present invention may contain, in addition to the repeating unit derived from the acrylate described above, a repeating unit derived from the acrylate shown below, if necessary:
Acrylic acid esters : methyl acrylate, ethyl acrylate, propyl acrylate, t-butyl acrylate, amyl acrylate, cyclohexyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-ethoxyethyl acrylate, 2,2-dimethyl-3-ethoxypropyl acrylate, 5-ethoxypentyl acrylate, 1-methoxyethyl acrylate, 1-ethoxyethyl acrylate, 1-methoxypropyl acrylate, 1-methyl-1-methoxyethyl Acrylate, 1- (isopropoxy) ethyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc .;
Methacrylic acid esters : methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, t-butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-ethoxyethyl methacrylate, 4-methoxy Butyl methacrylate, 5-methoxypentyl methacrylate, 2,2-dimethyl-3-ethoxypropyl methacrylate, 1-methoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-methoxypropyl methacrylate, 1-methyl-1-methoxyethyl methacrylate, 1 -(Isopropoxy) ethyl methacrylate, furfuryl meta Relate, tetrahydrofurfuryl methacrylate and the like;
Crotonic acid esters : methyl crotonate, ethyl crotonate, propyl crotonate, amyl crotonate, cyclohexyl crotonate, ethyl hexyl crotonate, octyl crotonate, crotonic acid-t-octyl, chloroethyl crotonate, 2-ethoxyethyl crotonate 2,2-dimethyl-3-ethoxypropyl crotonate, 5-ethoxypentyl crotonate, 1-methoxyethyl crotonate, 1-ethoxyethyl crotonate, 1-methoxypropyl crotonate, 1-methyl-1-methoxy Ethyl crotonate, 1- (isopropoxy) ethyl crotonate, benzyl crotonate, methoxybenzyl crotonate, furfuryl crotonate, tetrahydrofurfuryl crotonate, etc .; and
Itaconic acid esters : dimethyl itaconate, diethyl itaconate, dipropyl itaconate, diamyl itaconate, dicyclohexyl itaconate, bis (ethylhexyl) itaconate, dioctyl itaconate, itaconic acid-di-t-octyl, bis (chloroethyl) itaconate Bis (2-ethoxyethyl) itaconate, bis (2,2-dimethyl-3-ethoxypropyl) itaconate, bis (5-ethoxypentyl) itaconate, bis (1-methoxyethyl) itaconate, bis (1-ethoxyethyl) Itaconate, bis (1-methoxypropyl) itaconate, bis (1-methyl-1-methoxyethyl) itaconate, bis (1- (isopropoxy) ethyl) itaconate, dibenzyl itaconate, bis (methoxybenzyl) Takoneto, difurfuryl itaconate, and di-tetrahydrofurfuryl itaconate.

   Particularly preferred are acrylates or methacrylates having an alkyl group having a tertiary carbon at the ester oxygen α-position, such as t-butyl acrylate, t-butyl methacrylate, 1,1-dimethylpropyl acrylate, 1,1-dimethyl methacrylate. be able to.

  In the present invention, two or more kinds of repeating units derived from two or more kinds of compounds represented by formulas (I) to (IV) may be contained. For example, in the case of the repeating unit derived from the alkenylphenol derivative represented by the formula (I), the repeating unit derived from the alkenylphenol derivative represented by the formula (I-1) and the formula (I-2) Both may be included.

[Wherein R ¹ , R ² , m and n are as defined above, R ³¹ is a hydrogen atom and R ³² is a protecting group, or R ³¹ is a protecting group and R ³² is Another protecting group].
In the arm portion of the star polymer of the present invention, the ratio of each repeating unit can be arbitrarily selected based on the ratio of monomers used in the reaction. For example, the content of the repeating unit derived from the alkenylphenol derivative represented by the formula (I) is 1 to 100 mol%, preferably 10 to 100 mol%, more preferably 30 in all the repeating units of the arm part. ˜100 mol%. The content of the repeating unit derived from the styrene derivative represented by the formula (III) is 0 to 99 mol%, preferably 0 to 90 mol%, more preferably 0 to 0 in all the repeating units of the arm part. 70 mol%. Further, the content of the repeating unit derived from the acrylate derivative represented by the formula (IV) is 0 to 99 mol%, preferably 0 to 90 mol%, more preferably 0 to 0 in all the repeating units of the arm part. 70 mol%.

  The number average molecular weight Mn of the arm part is a polystyrene standard, preferably 1,000 to 300,000, more preferably 1,000 to 100,000, and still more preferably 2,000 to 20 by gel permeation chromatography. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably in the range of 1.01 to 3.00, more preferably 1.01 to 2.00, Is preferably in the range of 1.01-1.50.

The method for producing the star polymer of the present invention includes:
(1) In the presence of an anionic polymerization initiator, an arm portion is synthesized by anionic polymerization such as an alkenylphenol derivative represented by formula (I), and then an acrylate derivative represented by formula (II) is reacted. A method of forming the core;
(2) An anion such as an alkenylphenol derivative represented by formula (I) after forming a polyfunctional core by anionic polymerization of an acrylate derivative represented by formula (II) in the presence of an anionic polymerization initiator A method of forming an arm portion connected to the core portion by polymerization; and (3) synthesizing an arm portion by anionic polymerization of an alkenylphenol derivative represented by the formula (I) in the presence of an anionic polymerization initiator; Examples thereof include a method in which an acrylate derivative represented by the formula (II) is reacted to form a core portion and a monomer capable of anion polymerization is further reacted. The above methods (1) and (3) are preferable in that the reaction can be easily controlled and a star polymer having a controlled structure is produced.

  Examples of the anionic polymerization initiator used in the anionic polymerization method include alkali metals or organic alkali metals. Examples of the alkali metals include lithium, sodium, potassium, cesium, and the like. Examples of the alkali metal alkylates, allylates, arylates and the like include, specifically, ethyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, ethyl sodium, lithium Biphenyl, lithium naphthalene, lithium triphenyl, sodium naphthalene, α-methylstyrene sodium dianion, 1,1-diphenylhexyl lithium, 1,1-diphenyl-3-methylpentyl lithium and the like can be mentioned.

  The polymerization reaction for synthesizing the arm polymer in the above method (1) or (3) includes a method of dropping an anionic polymerization initiator in a monomer (mixed) solution, or a monomer (mixed) in a solution containing an anionic polymerization initiator. Any method of dropping the liquid can be used, but since the molecular weight and molecular weight distribution can be controlled, the method of dropping the monomer (mixed) liquid into the solution containing the anionic polymerization initiator is preferable. This arm polymer synthesis reaction is usually carried out in an organic solvent under an inert gas atmosphere such as nitrogen or argon at a temperature in the range of −100 to 50 ° C., preferably −100 to 40 ° C.

  Examples of the organic solvent used in the arm polymer synthesis reaction include aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons such as cyclohexane and cyclopentane, and aromatic carbonization such as benzene and toluene. In addition to ethers such as hydrogen, diethyl ether, tetrahydrofuran (THF) and dioxane, organic solvents usually used in anionic polymerization such as anisole and hexamethylphosphoramide can be mentioned. It can be used as a mixed solvent of more than one species. Of these, toluene, n-hexane, and THF can be preferably exemplified.

  Examples of polymerization forms when the arm part is a copolymer include random copolymers, partial block copolymers, and complete block copolymers in which each component is statistically distributed throughout the copolymer chain. These can be synthesized by selecting a method for adding monomers used for polymerization.

  In the reaction to form a star polymer by connecting the arm part thus obtained to the core part, an acrylate derivative represented by the formula (II) is further added to the reaction solution after completion of the synthesis reaction of the arm part. This can be done. This reaction is usually controlled by carrying out a polymerization reaction at −100 ° C. to 50 ° C., preferably −70 ° C. to 40 ° C. in an organic solvent under an inert gas atmosphere such as nitrogen or argon. In addition, a polymer having a narrow molecular weight distribution can be obtained. In addition, the star polymer formation reaction can be performed continuously in the solvent used to form the arm portion, and the composition is changed by adding a solvent or the solvent is replaced with another solvent. It can also be done. As such a solvent, a solvent similar to the solvent used in the arm portion synthesis reaction can be used.

  In the method for producing a star polymer of the present invention, the molar ratio [(P) / (D)] of the acrylate derivative (P) represented by the formula (II) and the active terminal (D) of the polymer chain of the arm part is 0. 1 to 10 is preferable, and 1 to 10 is more preferable. For the reaction between the arm polymer chain and the polyacrylate, either a method of adding a polyacrylate to an arm polymer chain having an active end or a method of adding an arm polymer chain having an active end to a polyacrylate can be employed. .

  The number of arms of the star polymer is determined by the amount of polyacrylate added, the reaction temperature, and the reaction time. Usually, the reactivity difference or steric hindrance between the end of the living polymer and the vinyl group of the acrylate derivative represented by formula (II) A plurality of star-shaped block copolymers having different numbers of arms are simultaneously generated under the influence of the above. Moreover, it is preferable that ratio (Mw / Mn) of the weight average molecular weight (Mw) and number average molecular weight (Mn) of the star polymer to produce | generate exists in the range of 1.01-3.00, and 1.01-2. 00, more preferably in the range of 1.01-1.50. The number average molecular weight of the produced star polymer is preferably 1,000 to 1,000,000, more preferably 3,000 to 1,000,000, still more preferably 5,000 to 500,000. The composition ratio of the polymer in the core part to the polymer chain in the arm part (core part / arm part) is preferably 1/1000 to 1 / 0.1, more preferably 1/100 to The range is 1 / 0.5, more preferably 1/50 to 1/1.

  An anion-polymerizable monomer is allowed to react with a core part (polyfunctional core) having an active end formed by reacting an arm polymer chain prepared in advance with an acrylate derivative represented by the formula (II). In the production method of (3) above in which a new arm polymer chain is formed, a star polymer having different types of arm polymer chains can be produced. The active terminal present in the central core can be reacted directly with a polymerizable monomer, but after reacting with a compound such as diphenylethylene or stilbene, an alkali metal or alkaline earth metal such as lithium chloride is also available. After adding the mineral acid salt, if the monomer is reacted, if a highly reactive monomer such as an acrylate derivative is reacted, the polymerization reaction can proceed slowly, and the entire star polymer produced It may be advantageous in controlling the structure. In addition, the above reaction can be continuously performed in the solvent used to form the central nucleus having an active end, the composition is changed by adding a solvent, or the solvent is replaced with another solvent. It can also be done. Examples of such a solvent include the same solvents as those used for the synthesis of the arm polymer. Also, two types of monomers are mixed as a polymer chain newly introduced as an arm part with respect to the active terminal present in the core part in the method (3), or as an arm polymer chain in the method (2). Thus, it is possible to obtain a polymer chain obtained by random copolymerization, or a block polymer chain by sequentially adding two kinds of monomers. Moreover, it is also possible to introduce a functional group at the terminal by adding carbon dioxide, epoxy or the like after the reaction is completed.

The reaction for removing the protecting group of the phenolic hydroxyl group from the copolymer thus obtained is not only the solvent exemplified in the polymerization reaction, but also alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, methyl In the presence of one or more mixed solvents such as polyhydric alcohol derivatives such as cellosolve and ethyl cellosolve, or water, hydrochloric acid, sulfuric acid, hydrogen chloride gas, hydrobromic acid, p-toluenesulfonic acid, 1, 1,1-trifluoroacetic acid, formula XHSO ₄ (wherein X represents an alkali metal such as Li, Na, K, etc.) as a catalyst at a temperature of room temperature to 150 ° C. Done. In this reaction, all or part of the protecting groups for the phenolic hydroxyl group can be removed by appropriately combining the type and concentration of the solvent, the type and addition amount of the catalyst, and the reaction temperature and reaction time.

  Moreover, when the repeating unit derived from the acrylate derivative represented by the formula (IV) is included in the arm part of the star polymer of the present invention, the ester group of the repeating unit is derived into a carboxyl group by hydrolysis. Can do. Hydrolysis can be carried out by a method known in the art, and can be carried out, for example, by acid hydrolysis under the same conditions as those for removing the protecting group. Preferably, the hydrolysis of the ester group is performed simultaneously with the removal of the phenolic hydroxyl group. A star polymer having an acrylic acid-based repeating unit in the molecule thus obtained is particularly preferable as a resist material because it has high alkali solubility.

  The star polymer of the present invention obtained by the above production method can be used without any particular purification, but may be purified if necessary. Although the said refinement | purification can be performed by the method normally used in the said technical field, it can be performed by the fractional reprecipitation method, for example. In the fractional reprecipitation method, it is preferable to perform reprecipitation using a mixed solvent of a polymer-soluble solvent and a low solvent. For example, a method of heating and dissolving the star polymer of the present invention in a mixed solvent and cooling, The product can be purified by dissolving the star polymer of the present invention in a solvent having high polymer solubility and then adding the solvent having low polymer solubility to precipitate the polymer.

  The present invention provides a star polymer that is useful for resist materials and the like, has a narrow molecular weight distribution, and a controlled structure.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, the scope of the present invention is not limited to an Example.
[Example 1]
Under a nitrogen atmosphere, 180 g of tetrahydrofuran (hereinafter abbreviated as THF) is maintained at −40 ° C., 7.7 g (10 mmol) of s-butyllithium in 11% cyclohexane (hereinafter abbreviated as SBL) is added, and the mixture is stirred. 4- (2-ethoxyethoxy) styrene (hereinafter abbreviated as PEES) 44.0 g (0.23 mol) was added dropwise over 30 minutes, and the reaction was continued for 30 minutes, followed by gas chromatography (hereinafter referred to as GC and GC). The completion of the reaction was confirmed. At this stage, a small amount was collected from the reaction system, and the reaction was stopped with methanol, followed by analysis by gel permeation chromatography (hereinafter abbreviated as GPC). As a result, the obtained polyPEES was Mn = 5,100, Mw / It was a monodisperse polymer with Mn = 1.06.

  Next, the reaction system was cooled to −60 ° C., 120 g of THF containing 0.1 mol of lithium chloride was added, 5.9 g (29 mmol) of ethylene dimethacrylate (hereinafter abbreviated as EDMA) was added dropwise, and the reaction was further carried out. The reaction was completed by GC for 1 hour. The reaction solution was poured into a large amount of methanol to precipitate a polymer, filtered and washed, and then dried under reduced pressure at 60 ° C. for 5 hours to obtain 49 g of a white powdery polymer. The polymerization yield based on the total amount of monomers used was 99%.

  When this polymer was analyzed by GPC, the target star polymer was Mn = 42,000 and Mw / Mn = 1.11. Moreover, the unreacted arm polymer part was Mn = 5,100 and Mw / Mn = 1.15.

  Next, 49 g of the obtained polymer was dissolved in THF to make a 30% solution, 2 g of concentrated hydrochloric acid was added and reacted at room temperature for 1 hour, and then the reaction solution was poured into a large amount of water to precipitate the polymer. After filtration and washing, it was dried under reduced pressure at 60 ° C. for 5 hours to obtain 33 g of a white powdery polymer.

  When the GPC analysis of this polymer was conducted, the target star polymer was Mn = 36,000 and Mw / Mn = 1.37. The arm polymer portion had Mn = 3,600 and Mw / Mn = 1.15.

^{By 13} C-NMR (solvent: acetone-d ₆ ), a signal of the para-position carbon of the aromatic ring of the p-hydroxystyrene unit was observed at around 155 ppm, and a signal of the carbonyl carbon of the EDMA unit was observed at around 176 ppm. From the results, it was confirmed that the composition ratio of p-hydroxystyrene and EDMA was 9/1.

From the above, the reaction and the subsequent elimination reaction were carried out as intended, and it was confirmed that p-hydroxystyrene-EDMA star polymer was produced.
[Example 2]
In a nitrogen atmosphere, 200 g of THF was maintained at −40 ° C., 7.7 g (10 mmol) of SBL was added, 44.0 g (0.23 mol) of PEES was added dropwise over 30 minutes with stirring, and the reaction was further continued for 30 minutes. The completion of the reaction was confirmed by GC. A small amount was collected from the reaction system at this stage, and after the reaction was stopped with methanol, analysis by GPC revealed that the obtained polyPEES was a monodisperse polymer with Mn = 4900 and Mw / Mn = 1.06. .

  Next, the reaction system was cooled to −60 ° C., 120 g of THF containing 0.1 mol of lithium chloride was added, and 6.1 g (43 mmol) of t-butyl methacrylate (tBMA) was added dropwise over 30 minutes. The reaction was continued for 30 minutes and the completion of the reaction was confirmed by GC. A small amount was collected from the reaction system at this stage, the reaction was stopped with methanol, and analyzed by GPC. As a result, the obtained PEES / tBMA copolymer had Mn = 5,500 and Mw / Mn = 1.07. It was a monodisperse polymer.

  Next, 5.9 g (0.03 mol) of EDMA was added dropwise, and the reaction was further continued for 1 hour, and the completion of the reaction was confirmed by GC. The reaction solution was poured into a large amount of methanol to precipitate a polymer, filtered and washed, and then dried under reduced pressure at 60 ° C. for 5 hours to obtain 55 g of a white powdery polymer. The polymerization yield based on the total amount of monomers used was 99%.

  When this polymer was analyzed by GPC, the target star polymer was Mn = 38000 and Mw / Mn = 1.08. Moreover, the unreacted arm polymer part was a mixture of Mn = 5500 and Mw / Mn = 1.14.

  Next, 55 g of the obtained polymer was dissolved in THF to make a 30% solution, 2 g of concentrated hydrochloric acid was added and reacted at room temperature for 1 hour, and then the reaction solution was poured into a large amount of water to precipitate the polymer. After filtration and washing, it was dried under reduced pressure at 60 ° C. for 5 hours to obtain 33 g of a white powdery polymer.

  When the GPC analysis of this polymer was conducted, the target star polymer was Mn = 32000 and Mw / Mn = 1.27. Moreover, the arm polymer part was Mn = 3300 and Mw / Mn = 1.36.

^{By 13} C-NMR, the signal of the para-position carbon of the aromatic ring of the p-hydroxystyrene unit is around 155 ppm, the signal of the carbonyl carbon of the EDMA unit is around 176 ppm, and the tertiary carbon of the t-butyl group of the tBMA unit is around 80 ppm. A signal was observed, and from each integration ratio, it was confirmed that the composition ratio of p-hydroxystyrene, tBMA, and EDMA was 75/15/10.

From the above, the reaction and the subsequent elimination reaction were carried out as intended, and it was confirmed that p-hydroxystyrene-tBMA-EDMA star polymer was produced.
[Example 3]
Under a nitrogen atmosphere, a mixed solvent of 260 g of THF and 30 g of n-hexane was kept at −40 ° C., 8.5 g (20 mmol) of n-butyllithium (hereinafter abbreviated as NBL) was added, and pt− 43.7 g (0.25 mol) of butoxystyrene (hereinafter abbreviated as PTBST) was added dropwise over 30 minutes, and the reaction was further continued for 30 minutes, and the completion of the reaction was confirmed by GC. A small amount was collected from the reaction system at this stage, the reaction was stopped with methanol, and analyzed by GPC. As a result, the obtained poly PTBST was a monodisperse polymer with Mn = 2600 and Mw / Mn = 1.09. .

  Next, the reaction system was cooled to −60 ° C., 150 g of THF containing 0.1 mol of lithium chloride was added, and then 6.5 g (33 mmol) of 1-ethylcyclohexyl methacrylate (ECHMA) was added dropwise over 30 minutes to further react. For 30 minutes, and the completion of the reaction was confirmed by GC. A small amount was collected from the reaction system at this stage, and the reaction was stopped with methanol, and then analyzed by GPC. The obtained PTBST / ECHMA copolymer was a monodisperse of Mn = 2700 and Mw / Mn = 1.09. It was a polymer.

  Next, 9.8 g (50 mmol) of EDMA was added dropwise, and the reaction was further continued for 1 hour, and the completion of the reaction was confirmed by GC. The reaction solution was poured into a large amount of methanol to precipitate a polymer, filtered, washed, and dried under reduced pressure at 60 ° C. for 5 hours to obtain 59 g of a white powdery polymer. The polymerization yield based on the total amount of monomers used was 99%.

  When this polymer was analyzed by GPC, the target star polymer was Mn = 21000 and Mw / Mn = 1.15. Moreover, the unreacted arm polymer part was Mn = 2700 and Mw / Mn = 1.18.

  Next, 59 g of the obtained polymer was dissolved in toluene / ethanol (1/1) to make a 30% solution, 3 g of concentrated sulfuric acid was added, and the reaction was carried out at 70 ° C. for 3 hours. The polymer was deposited to precipitate, filtered, washed and dried under reduced pressure at 60 ° C. for 5 hours to obtain 43 g of a white powdery polymer.

  When the GPC analysis of this polymer was conducted, the target star polymer was Mn = 17,000 and Mw / Mn = 1.16. The arm polymer portion had Mn = 2,700 and Mw / Mn = 1.16.

^{By 13} C-NMR, a signal of the para-position carbon of the aromatic ring of the p-hydroxystyrene unit was observed near 155 ppm, and a signal of the carbonyl carbon of the EDMA unit was observed near 176 ppm, and the signal of the ECHMA unit near 85 ppm disappeared.

From the above, the reaction and the subsequent elimination reaction were carried out as intended, and it was confirmed that p-hydroxystyrene-methacrylic acid-EDMA star polymer was produced.

Claims (6)

A star polymer comprising a core part as a central core and an arm part as a polymer chain linked to the central core,
Formula (IV) where the arm portion is coupled to the core portion:

[Wherein R ⁹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, and R ¹⁰ is an organic group having an alicyclic skeleton]
And a repeating unit derived from an acrylate derivative represented by formula (I):

[Wherein, R ¹ is a hydrogen atom or a C ₁ -C ₄ alkyl group, R ² is a halogen atom or a C ₁ -C ₁₂ hydrocarbon group, R ³ is a hydrogen atom or a protecting group, and m is An integer of 0 to 4, R ² may be the same or different when m is 2 or more, n is 1 or 2, and when n is 2, R ³ may be the same or different , M + n is an integer from 1 to 5]
A polymer chain of a block copolymer comprising repeating units derived from an alkenylphenol derivative represented by:
The core part has the formula (II):

Wherein R ⁴ and R ⁵ are each independently selected from a hydrogen atom and a C ₁ -C ₄ alkyl group, x is 1, R ⁶ is a — (CHR ¹¹ ) _p — group, p Is an integer of 2 to 6, and each R ¹¹ is independently a hydrogen atom or a C _{1 to} C ₄ alkyl group]
The said star polymer which is a polymer derived from the acrylate derivative represented by these. The star polymer according to claim 1 , wherein the number average molecular weight is 1,000 to 1,000,000. The star polymer according to claim 1 or 2 , wherein the molecular weight dispersity (weight average molecular weight / number average molecular weight) is 1.01 to 3.00. The composition ratio (core part / arm part) of the polymer of the core part and the polymer chain of the arm part (1/1000 to 1 / 0.1) is according to any one of claims 1 to 3 . Star polymer. The resist composition containing the star polymer of any one of Claims 1-4 . a) obtaining a polymer chain by polymerizing the alkenylphenol derivative represented by formula (I) according to claim 1;
b) polymerizing the polymer chain with the acrylate derivative of formula (IV) according to claim 1 to obtain a copolymer; and c) the copolymer with the formula according to claim 1. A step of copolymerizing with the acrylate derivative represented by (II);
Hints, in the case of R ³ protecting groups in Formula (I), may include the step of further removing the protecting group, a method of producing a star polymer according to any one of claims 1 to 4 .