JP2001139626A - Alkenylphenol polymer and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ESCAP type polymer as a resist material for a chemical amplification type excimer laser, capable of selectively and partly separating and decomposing a protective group of a phenolic hydroxy group by an acid, having a controlled structure containing no carboxylic acid residue, a narrow dispersiveness and an excellent resolving capacity. SOLUTION: This alkenylphenol copolymer having a ratio (Mw/Mn) of weight average mol.wt. (Mw) to number average mol.wt. (Mn)of 1.00-1.05 and no carboxylic acid residue is synthesized first by obtaining a block copolymer comprising an alkenylphenol having a protected phenolic hydroxy, or the alkenyphenol and a vinyl aromatic compound, and a (meth) acrylic ester, by an anion polymerization, then a specific amount of a protective group of the phenolic hydroxy group is separated or decomposed using an acidic agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a narrowly-dispersed alkenylphenol-based copolymer and a method for producing the same, which have not been known. More specifically, the present invention relates to an alkenylphenol unit, an alkenylphenyl ether unit, and (meth)
The present invention relates to an alkenylphenol copolymer having an acrylic ester unit as an essential constituent unit, having a narrow dispersibility, and having a controlled structure, and a method for producing the same. The alkenylphenol-based copolymer of the present invention is expected to be used as a resist material for excimer laser.

[0002]

2. Description of the Related Art Hitherto, alkenylphenol copolymers useful as resist materials have been well known. For example, JP-A-4-21258 and JP-A-7-209
868, JP-A-7-49569, JP-A-9
-160244 and JP-A-11-125907
Japanese Patent Application Laid-Open Publication No. H10-157, describes a random copolymer containing a repeating unit represented by the general formula (I), the general formula (II), and the general formula (III). Also, JP-A-11-125907
Japanese Patent Application Laid-Open Publication No. H10-15083 discloses that (A) (a) an alkali-insoluble or hardly soluble resin protected by an acid-dissociable group, and a resin which becomes alkali-soluble when the acid-dissociable group is dissociated. A positive-type radiation-sensitive resin composition is described. As the resin component, the following formula (VI) (wherein R ₁₃ and R ₁₄ independently represent a hydrogen atom or a methyl group, and R ₁₅ represents hydrogen Atom, t-butoxy group, etc.) are described.

[0003]

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Japanese Patent Application Laid-Open No. Hei 10-265524 discloses a compound represented by the following general formula (VII) (wherein R represents a hydroxyl group or OR
₂₀ groups are shown, and R ₂₀ represents an acid labile group. )) The intramolecular and / or intermolecular structure obtained by reacting a part of the phenolic hydroxyl group and / or carboxyl group represented by R of the polymer compound having a repeating unit with an alkenyl ether compound or a halogenated alkyl ether compound. And the total amount of the acid labile groups and the cross-linking groups is more than 0 mol% and more than 80 mol% of the total average of the phenolic hydroxyl groups and carboxyl groups. Weight average molecular weight of 1,000
~ 500,000 high molecular compounds have been described.

[0005]

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Japanese Patent Application Laid-Open No. 10-53621 discloses a compound represented by the following general formula (VIII), wherein R ₂₁ represents a hydrogen atom or a lower alkyl group, and R ₂₃ and R ₂₄ are substituted with a hydrogen atom or a halogen. Represents an alkyl group or the like which may be
R ₂₅ represents an alkyl group or the like which may be substituted with a halogen, and R ₂₆ represents a carboxyl group or the like which may be substituted with an alkyl group. And a polymer having a dispersity of 1 or more and less than 1.5.

[0007]

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[0008]

Alkenylphenol homopolymers and copolymers represented by poly-p-hydroxystyrene and the like are useful as resist materials for chemically amplified excimer lasers. Is a so-called ESCAP type resist capable of achieving high resolution.

[0009] Advances in high resolution technology in this field are remarkable, and higher resolution is always required. The structure of the ESCAP type polymer desired to realize higher resolution is a structure having a protecting group which can be eliminated and decomposed by an acid generated upon exposure to a part of the alkenylphenol moiety, and What has a narrow molecular weight distribution and a controlled structure is desired. With such a structure, an unnecessary excessive diffusion of an acid generated from a photoacid generator in a resist composition is suppressed, and an effect of suppressing the solubility of a phenolic hydroxyl group or a carboxyl group in an excessive alkali developer is suppressed. Thus, it is expected that the resist material will contribute to higher resolution.

Many of the ESCAP-type polymers which have been reported so far with such a structure have been synthesized by radical polymerization and have a dispersity (Mw / Mn) of 1.50 or more, which is not satisfactory. Did not. Although JP-A-10-265524 describes an ESCAP-type polymer having a narrow molecular weight distribution and a controlled structure, an ester moiety as a protective group does not leave an acid such as a methyl group. Or a group having a carboxylic acid residue, and the structure of such an ester portion is difficult to realize a difference in solubility between an exposed portion and an unexposed portion in an alkali developing solution, and is not satisfactory. However, since the method of partially introducing the above-mentioned protecting group into a hydroxyl group or a carboxylic acid group later is employed, it is particularly difficult to completely protect the carboxylic acid portion in the polymer. I was

Although JP-A-11-125907 describes a random copolymer or a block copolymer, it does not disclose a method for synthesizing such a polymer or a molecular weight distribution. 10-53
Japanese Patent No. 621 discloses an ESCAP type polymer having a small degree of dispersion, but specifically describes only a random copolymer, which is not satisfactory as a high-resolution resist material. Was.

An object of the present invention is to provide a narrow-dispersion ES having a structure in which a protecting group for a phenolic hydroxyl group is selectively and partially eliminated and decomposed by an acid, and has a structure containing no carboxylic acid residue.
It is to provide a CAP type polymer.

[0013]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that alkenylphenols having a protected phenolic hydroxyl group or alkenylphenols and vinyl aromatic compounds, ) It has been found that a block copolymer composed of an acrylate ester can selectively and partially remove and decompose a protecting group for a phenolic hydroxyl group with an acid, and the molecular weight distribution is narrow from the block copolymer, and It has been confirmed that an alkenylphenol copolymer having a controlled structure can be synthesized, and the present invention has been completed.

That is, the present invention provides a compound represented by the general formula (I)

Embedded image (Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents
Represents a C1 to C5 alkyl group, m represents 0, 1 or 2, and when m is 2, R ₂ may be the same or different. ) And the general formula (II)

Embedded image (Wherein, R ₃ represents a hydrogen atom or a methyl group, and R ₄ is
Represents an acid release and decomposition group, R ₅ represents an alkyl group of C1 to C5, n is 0, 1 or 2, when n is 2, R ₅
May be the same or different. And a component (A) containing a repeating unit represented by the general formula (III)

Embedded image (Wherein, R ₆ represents a hydrogen atom or a methyl group, and R ₇ is t
-Represents an acid leaving / decomposing group having a butyl group. And the component (B) containing the repeating unit represented by (A)-(B)
In the copolymer block-bonded to the mold, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / M
n) is in the range of 1.00 to 1.50 and has no carboxylic acid residue, and an alkenylphenol-based copolymer characterized by having a weight average molecular weight of 1,000 to
The present invention relates to the above alkenylphenol copolymer having a molecular weight of 100,000.

Further, the present invention provides a compound represented by the following general formula (IV) wherein the hydroxyl group of a phenol residue is protected by an anionic polymerization method using an anionic polymerization initiator as a polymerization initiator.

Embedded image (Wherein, R ₈ represents a hydrogen atom or a methyl group, and R ₉ is
Represents an acid leaving / decomposing group, R ₁₀ represents a C1-C5 alkyl group, p represents 0, 1 or 2, and when p is 2, R _{10 represents}
May be the same or different. ), Or after copolymerizing a compound represented by the general formula (IV) with a vinyl aromatic compound, the following general formula (V)

Embedded image (Wherein, R ₁₁ represents a hydrogen atom or a methyl group, and R ₁₂ is
It represents an acid leaving / decomposing group having a t-butyl group. ), A phenolic hydroxyl-protecting group is desorbed and decomposed by a predetermined amount from a block copolymer obtained by copolymerizing with a (meth) acrylic acid ester represented by the formula (1) using an acidic reagent. The method for producing an alkenylphenol copolymer described above, and the step of removing and decomposing a phenolic hydroxyl-protecting group by a predetermined amount using an acidic reagent at a temperature of less than 60 ° C. The present invention relates to a method for producing a copolymer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the "repeating unit represented by formula (I)" of the present invention, in the formula, R ₁ represents a hydrogen atom or a methyl group. R ₂ represents a C1 to C5 alkyl group, and examples of the C1 to C5 alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-alkyl group.
Specific examples include a butyl group, a t-butyl group, and the like. m represents 0, 1 or 2, and when m is 2, R ₂ may be the same or different. In addition, hydroxyl groups (OH
Group) and the substitution position of R ₂ are not particularly limited, but the hydroxyl group is preferably a para-position or a meta-position of an alkenyl group.

In the "repeating unit represented by formula (II)" of the present invention, R ₃ represents a hydrogen atom or a methyl group. R ₄ represents an acid leaving / decomposing group, that is, a group capable of leaving and / or decomposing by an acid. Specific examples of the acid leaving / decomposing group include functional groups represented by the following formulas and the like. Can be.

[0018]

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R ₅ represents a C1 to C5 alkyl group. Examples of the C1 to C5 alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an n-alkyl group.
Specific examples include a butyl group, a t-butyl group, and the like. n represents 0, 1 or 2, and when n is 2, R ₅ may be the same or different. The substitution position of the alkoxy group (OR ₄ group) and R ₅ is not particularly limited, but the alkoxy group (OR ₄ group) is preferably in the para or meta position of the alkenyl group.

In the "repeating unit represented by formula (III)" of the present invention, R ₆ represents a hydrogen atom or a methyl group. R ₇ represents an acid elimination / decomposition group having a t-butyl group, and the acid elimination / decomposition group having a t-butyl group is represented by the following formula (where u represents 0 or 1) )) Can be specifically exemplified.

[0021]

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If necessary, the polymer of the present invention may contain a repeating unit other than the repeating units represented by formulas (I) to (III). The repeating unit is not particularly limited as long as it is a repeating unit obtained from a compound having a double bond copolymerizable with monomers corresponding to general formulas (I) to (III). Preferred is a repeating unit having no acidic substituent such as a carboxyl group or a phenolic hydroxyl group, and a monomer corresponding to the repeating unit includes a vinyl group-containing compound,
A (meth) acryloyl group-containing compound can be exemplified.

Examples of the vinyl group-containing compound include aromatic vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, 1,1-diphenylethylene, and stilbene; heteroatom-containing aromatic vinyl compounds such as vinylpyridine; Specific examples include vinyl ketone compounds such as ketone and ethyl vinyl ketone, vinyl ether compounds such as methyl vinyl ether and ethyl vinyl ether, and heteroatom-containing alicyclic vinyl compounds such as vinyl pyrrolidone and vinyl lactam.

The above (meth) acryloyl group-containing compound includes a compound represented by the following general formula (IX) (wherein R ₂₈ represents a hydrogen atom or a methyl group, R ₂₉ represents a C1 to C12 alkyl group, and a C3 or more A (meth) acrylate or (meth) represented by a hydrocarbon group having an alicyclic skeleton, a hydrocarbon group having a C2 or more alicyclic skeleton containing a hetero atom, or a heteroaryl group. Acrylonitrile and the like can be exemplified.

[0025]

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R ₂₉ in the general formula (IX) represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
Specific examples thereof include -butyl group, t-butyl group, n-octyl group, n-decyl group and the like, or a functional group represented by the following formula (where k represents 0 or 1). .

[0027]

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These vinyl group-containing compounds and (meth) acryloyl group-containing compounds can be used as one kind or a mixture of two or more kinds. Compounds obtained from these vinyl group-containing compounds and (meth) acryloyl group-containing compounds can be used. The repeating unit to be obtained can be copolymerized with the repeating units represented by the general formulas (I) to (III) at random or in blocks to be contained in the alkenylphenol copolymer of the present invention. For example, as the component (A) containing the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II), a repeating unit corresponding to styrene, α-methylstyrene, or the like as a monomer Component (A) that also contains In the component (A), a repeating unit represented by the general formula (I), a repeating unit represented by the general formula (II) and styrene as a monomer, α
The molar ratio to the total of the repeating units corresponding to -methylstyrene or the like is preferably in the range of 99/1 to 50/50.

The alkenylphenol copolymer of the present invention is represented by the following general formula (III) and the component (A) containing the alkenylphenol repeating unit represented by the general formula (I) or (II). (A)-(B) block copolymerization with a component (B) containing a repeating unit of (meth) acrylic acid ester. Specific examples of the alkenylphenol copolymer of the present invention include the following.

Poly [pt-butoxystyrene / p-hydroxystyrene / t-butyl (meth) acrylate] Poly [pt-butoxy-α-methylstyrene / p-hydroxystyrene / t- (meth) acrylate -Butyl] poly [pt-butoxystyrene / p-hydroxy-α
-Methylstyrene / t-butyl (meth) acrylate] poly [mt-butoxystyrene / m-hydroxystyrene / t-butyl (meth) acrylate] poly [pt-butoxystyrene / p-hydroxystyrene / (T-butyl methacrylate / t-butyl acrylate) poly [pt-butoxystyrene / p-hydroxystyrene / t-butyl (meth) acrylate / isobonyl (meth) acrylate] poly [pt-butoxy] Styrene / p-hydroxystyrene / dicyclopentenyl (meth) acrylate / t-butyl (meth) acrylate] poly [p- (1-ethoxyethoxy) styrene / p-hydroxystyrene / t-butyl (meth) acrylate ] Poly [pt-butoxystyrene / p-hydroxystyrene / t-butoxycarbonylmethyl (meth) acrylate ] Poly [p- (tetrahydropyranyloxy) styrene / p-hydroxystyrene / t-butyl (meth) acrylate] poly [pt-butoxystyrene / p- (tetrahydropyranyloxy) styrene / p-hydroxystyrene /
T-butyl (meth) acrylate] poly [pt-butoxystyrene / styrene / p-hydroxystyrene / t-butyl (meth) acrylate]

The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) representing the degree of dispersion of the alkenylphenol copolymer of the present invention is in the range of 1.00 to 1.50, Preferably it is in the range of 1.00 to 1.20. The weight average molecular weight (Mw) is 1,000 to 1
It is preferably in the range of 00,000, especially 1,000 to 30,000. And the molar ratio of component (A) to component (B)
[(A) / (B)] is preferably in the range of 95/5 to 5/95, particularly preferably in the range of 95/5 to 70/30. The molar ratio of the alkenylphenol repeating unit represented by the general formula (I) and the alkenylphenol repeating unit represented by the general formula (II) constituting the component (A) is not particularly limited. 5 / 0.5 to 50/50, especially 95
/ 5 to 60/40 is preferred.

In the compound represented by the general formula (IV) used in the method for producing an alkenylphenol copolymer of the present invention, R ₈ represents a hydrogen atom or a methyl group, R ₉ represents an acid leaving / decomposing group, R ₁₀ represents a C1 to C5 alkyl group, p represents 0, 1 or 2, and when p is 2, R ₁₀ may be the same or different. R ₉ corresponds to R ₄ in the general formula (II), and R ₁₀ corresponds to R ₅ in the general formula (II), and specific examples are as described above.

Specific examples of the compound represented by the general formula (IV) include pt-butoxystyrene, pt-butoxy-α-methylstyrene, mt-butoxystyrene and m-t-butoxystyrene.
-T-butoxy-α-methylstyrene, p- (tetrahydropyranyloxy) styrene, p- (tetrahydropyranyloxy) -α-methylstyrene, p- (1-ethoxyethoxy) styrene, p- (1-ethoxy) Ethoxy) -α-methylstyrene and the like can be exemplified, and these can be used alone or as a mixture of two or more.

The vinyl aromatic compound used in the method for producing an alkenylphenol copolymer of the present invention includes styrene, o-methylstyrene, p-methylstyrene, pt-butylstyrene, α-methylstyrene,
Examples thereof include 1,3-butylstyrene, 1,1-diphenylethylene, and stilbene, and these can be used alone or as a mixture of two or more.

The alkenylphenol copolymer of the present invention
Represented by the general formula (V) used in the production method
R in the (meth) acrylate₁₁Is a hydrogen atom
Or a methyl group represented by R₁₂Is t- which can be desorbed and decomposed by acid
Represents a group having a butyl group. R ₁₂Is in the general formula (III)
R₇And a specific example is as described above. one
Specific examples of the compound represented by the general formula (V) include (meth)
(T) t-butyl acrylate, t-butyl (meth) acrylate
Toxycarbonylmethyl, 1-methyl (meth) acrylate
Examples of tert-butoxycarbonylmethyl
Can be used alone or as a mixture of two or more.
Can be used.

In the production of the alkenylphenol-based copolymer of the present invention, first, the compound represented by the general formula (IV) alone or the compound represented by the general formula (IV) is used by using an anionic polymerization initiator as a polymerization initiator. Anion polymerization is carried out with the compound and a vinyl aromatic compound.
This is performed by a block copolymerization reaction in which a (meth) acrylate represented by the following formula is added. This reaction is usually performed in an organic solvent under an atmosphere of an inert gas such as nitrogen or argon at a temperature of -100 to 50 ° C, preferably at -100 to 0 ° C, more preferably at -100 to -20 ° C. Done.

Examples of the anionic polymerization initiator used in the above anionic polymerization method include alkali metals and organic alkali metals. Examples of the alkali metals include lithium, sodium, potassium, cesium and the like. Examples of the organic alkali metal include alkylated products, allylic products, and arylated products of the above-mentioned alkali metals. These anionic polymerization initiators can be used alone or in combination of two or more. Further, as the organic alkali metal, ethyl lithium,
n-butyllithium, sec-butyllithium, t-butyllithium, ethyl sodium, lithium biphenyl, lithium naphthalene, lithium triphenyl, sodium naphthalene, α-methylstyrene sodium dianion, 1,1-diphenylhexyllithium, 1,1
-Diphenyl-3-methylpentyllithium and the like can be specifically mentioned.

Examples of the organic solvent used in the above polymerization reaction include aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons with cyclohexane and cyclopentane, and aromatic hydrocarbons such as benzene and toluene. In addition to hydrogens, ethers such as diethyl ether, tetrahydrofuran, and dioxane, organic solvents commonly used in anionic polymerization such as anisole and hexamethylphosphoramide can be used, and these can be used alone or in combination of two or more. Can be used as a solvent. In particular, a combination of a polar solvent and a non-polar solvent is preferable, and a combination of an ether and an aromatic or aliphatic hydrocarbon is more preferable.

When the copolymerization is carried out by adding a (meth) acrylate, the polymerization reaction can be controlled by adding an alkali metal salt and / or an alkaline earth metal salt of a mineral acid. As the alkali metal salt and / or alkaline earth metal salt of a mineral acid, lithium chloride is particularly preferred.

The phenolic hydroxyl-protecting group is eliminated and decomposed in a predetermined amount from the thus obtained copolymer using an acidic reagent to form an alkenylphenol skeleton. Examples of the solvent used in the elimination / decomposition reaction include, in addition to the solvents exemplified in the above polymerization reaction, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, and polyhydric alcohols such as methyl cellosolve and ethyl cellosolve. One or a mixture of two or more solvents such as derivatives and water can be exemplified.

The acidic reagent used is not particularly limited, but specific examples thereof include hydrochloric acid, sulfuric acid, hydrogen chloride gas, phosphoric acid, hydrobromic acid, p-toluenesulfonic acid, 1,1,1
- trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, in formula XHSO ₄ (wherein, X is Li,
Represents an alkali metal such as Na and K. )) And the like. The amount to be used is sufficient with the amount of the catalyst, but the average molecular weight of the entire polymer is usually determined from the molar fraction of each unit and the molecular weight of each unit, and the molar amount of each unit is determined from the total weight, average molecular weight, and molar fraction of the polymer. The number is determined, and it is in the range of 0.1 to 3 equivalents, preferably 0.1 to 1 equivalent based on the number of moles of the alkenylphenol unit.

The elimination reaction of the protecting group is usually carried out at room temperature to 150.
Performed at a temperature of ° C. However, at the time of deprotection of the phenolic hydroxyl group, in order to control the hydrolysis of the (meth) acrylate portion, the temperature is in the range of room temperature to less than 70 ° C, preferably room temperature to less than 60 ° C, more preferably 30 ° C to 50 ° C. Done in However, C is added to the (meth) acrylate part.
When the compound has a bulky substituent such as an alkyl group having 7 or more alicyclic groups or an alicyclic group, the hydrolysis of the ester moiety may be controlled even when the reaction is performed at 60 ° C. or more.

In the deprotection reaction, by appropriately combining the type and concentration of the solvent, the type and amount of the catalyst, and the reaction temperature and the reaction time, the hydrolysis of the (meth) acrylate portion and the phenolic hydroxyl group Deprotection can be controlled. For example, at the beginning of the reaction, the reaction is carried out while maintaining the temperature at 60 ° C., and after a predetermined amount of 80 to 90% is desorbed, the reaction temperature is lowered, and if necessary, water is added to adjust the acid concentration. The rate of the elimination reaction can be controlled, and as a result, the target product can be obtained with an accuracy of about ± 1% with respect to a predetermined amount.

In order to eliminate a desired predetermined amount of the protecting group, the reaction is monitored sequentially, and the reaction is stopped when the predetermined amount is eliminated. As a means for tracking the reaction, a method of measuring a change in the IR spectrum or the solubility of the polymer can be exemplified.

[0045]

The present invention will be described below in more detail with reference to examples. However, the scope of the present invention is not limited by the following examples.

Example 1 Tetrahydrofuran (THF) under a nitrogen atmosphere
While maintaining 1500 g at -60 ° C, 30 mol of n-butyllithium (NBL) was added, and 0.8 mol of pt-butoxystyrene (PTBST) and styrene (S
t) 0.2 mol of the mixture was added dropwise over 1 hour, and the reaction was further continued for 1 hour.
C) The completion of the reaction was confirmed. Next, 0.5 mol of t-butyl methacrylate (t-BMA) was added dropwise over 30 minutes, the reaction was further continued for 1 hour, the completion of the reaction was confirmed by GC, and the reaction was stopped by adding methanol to the reaction system. . The reaction solution was poured into a large amount of methanol to precipitate a polymer, which was filtered, washed, and dried under reduced pressure at 60 ° C. for 5 hours to obtain a white powdery polymer. The polymerization yield based on the total amount of the monomers used was 99.5%.

The polymer was subjected to gel permeation chromatography (GPC) analysis to find that Mn =
8,600, Mw / Mn = 1.17, and the copolymerization ratio determined by ¹³ CNMR was PTBS
T unit / St unit / t-BMA unit = 0.8 / 0.2 /
0.5 (molar ratio). From these facts, it was confirmed that the copolymerization reaction proceeded without any side reaction, and that the copolymer as set was obtained.

Next, 10 g of the obtained polymer was added to THF /
Dissolve in a mixed solvent of ethanol = 4/1 (weight ratio) and add 2
After preparing a 5% solution and heating to 40 ° C., 3 g of concentrated hydrochloric acid was added to the reaction system to start a debutylation reaction. And successively,
A small amount was sampled from the reaction system, and the reaction was followed by measuring the IR spectrum. After confirming that the desorption reached a predetermined amount, the reaction system was quickly cooled in an ice water bath, and the reaction solution was poured into a large amount of water. The polymer was charged to precipitate the polymer, filtered, washed, and dried under reduced pressure at 60 ° C. for 5 hours to obtain 7.7 g of a white powdery polymer.

GPC analysis of this polymer revealed that it was a monodisperse polymer with Mn = 7900 and Mw / Mn = 1.16. The copolymerization ratio determined by ¹³ CNMR was:
PTBST unit / vinyl phenol (PHS) unit / S
t unit / t-BMA unit = 0.4 / 0.4 / 0.2 /
0.5 (molar ratio).

[0050]

According to the present invention, a copolymer of a hydroxyl-protected alkenylphenol and a (meth) acrylic acid ester is synthesized by an anionic polymerization method, and the phenol hydroxyl group is selectively eliminated. Synthesizing an ESCAP-type alkenylphenol copolymer having a structure-controlled, narrowly dispersible, partially protected phenolic hydroxyl group, and having a higher resolution than conventional KrF resists for shixima lasers. Can be.

Claims (4)

[Claims] 1. A compound of the general formula (I) (Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents
Represents a C1 to C5 alkyl group, m represents 0, 1 or 2, and when m is 2, R ₂ may be the same or different. And a repeating unit represented by the general formula (II): (Wherein, R ₃ represents a hydrogen atom or a methyl group, and R ₄ is
Represents an acid release and decomposition group, R ₅ represents an alkyl group of C1 to C5, n is 0, 1 or 2, when n is 2, R ₅
May be the same or different. And a component (A) containing a repeating unit represented by the general formula (III): (Wherein, R ₆ represents a hydrogen atom or a methyl group, and R ₇ is t
-Represents an acid leaving / decomposing group having a butyl group. And the component (B) containing the repeating unit represented by (A)-(B)
In the copolymer block-bonded to the mold, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / M
alkenylphenol-based copolymer, wherein n) is in the range of 1.00 to 1.50 and has no carboxylic acid residue. 2. The weight average molecular weight is 1,000 to 10.
The alkenyl phenol copolymer according to claim 1, wherein the alkenyl phenol copolymer is 000. 3. A compound represented by the following general formula (IV) in which a hydroxyl group of a phenol residue is protected by an anionic polymerization method using an anionic polymerization initiator as a polymerization initiator. (Wherein, R ₈ represents a hydrogen atom or a methyl group, and R ₉ is
Represents an acid leaving / decomposing group, R ₁₀ represents a C1-C5 alkyl group, p represents 0, 1 or 2, and when p is 2, R _{10 represents}
May be the same or different. ), Or after copolymerizing a compound represented by the general formula (IV) with a vinyl aromatic compound, the compound represented by the following general formula (V): (Wherein, R ₁₁ represents a hydrogen atom or a methyl group, and R ₁₂ is
It represents an acid leaving / decomposing group having a t-butyl group. ), A phenolic hydroxyl-protecting group is desorbed and decomposed by a predetermined amount from a block copolymer obtained by copolymerizing with a (meth) acrylic acid ester represented by the formula (1) using an acidic reagent. The method for producing an alkenylphenol-based copolymer according to claim 1 or 2. 4. A step of desorbing and decomposing a phenolic hydroxyl-protecting group by a predetermined amount using an acidic reagent at 60 ° C.
4. The method for producing an alkenylphenol-based copolymer according to claim 3, wherein the reaction is carried out at less than 10%.