JPH10168132A - Alkenylphenol-based copolymer having narrow distribution and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject copolymer having a single peak and a narrow molecular weight distribution by polymerizing a specific protected phenol compound, subsequently block-copolymerizing the resultant product with a (meth)acrylic acid alkyl ester and further copolymerizing the resultant block-copolymer with a (meth)acrylic acid ester. SOLUTION: A compound of formula I (R1 is H or methyl; R6 is a 1-6C alkyl), in which the hydroxyl group of the phenol residue is protected with a saturated aliphatic protecting group, is homo-polymerized or copolymerized with a vinyl aromatic compound. Subsequently, the resultant product is block-copolymerized with a (meth) acrylic acid alkyl ester of formula II (R2 is H or methyl; R4 is a (substituted) 1-12C alkyl or a heterocycle]. Further subsequently, the resultant block-copolymer is copolymerized with a (meth)acrylic acid ester of formula III [R3 is H or methyl; R5 is a (substituted) 7-15C alicyclic group or an alkyl having the alicyclic group]. Then, the protecting group of formula I is removed to obtain the objective copolymer. The obtained copolymer consists of a structural unit of formula IV to formula VI and has a number average molecular weight of 1000-50,000, a ratio of a number average molecular weight (Mn ) to a weight average molecular weight (Mw ), Mw /Mn , is 1.00-1.50 and a ratio of formula V/formulae (V+VI) is 1/9 to 9/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a narrow-dispersion alkenylphenol-based copolymer, and more particularly to a copolymer having a number average molecular weight of 1,000 to 50,000, a number average molecular weight (Mn) and a weight average molecular weight. (Mw) and Mw / Mn
= 1.00 to 1.50, and a method for producing the same. The copolymer of the present invention is expected to be used as an excimer laser resist material.

[0002]

2. Description of the Related Art It is known that alkenylphenol homopolymers and copolymers represented by poly-p-hydroxystyrene are useful as chemically amplified excimer laser resist materials. Among copolymers, copolymers with (meth) acrylates have conventionally been produced by thermally polymerizing vinylphenol monomers and (meth) acrylate monomers.

[0003] High integration of LSIs is progressing year by year, and at the same time, miniaturization of patterns is required. Photolithography technology using light exposure is used for fine processing. As a next-generation technology, a 256 Mb DRAM that requires a 0.25 μm rule is expected to use excimer lithography using KrF excimer laser light. Recently, homopolymers of poly-p-hydroxystyrene and copolymers with styrene have begun to be used as base resins for KrF excimer laser resists. The latent image forming reaction of the chemically amplified resist includes an acid generating reaction (during exposure) and a catalytic reaction (post exposure bak).
ing-PEB). For this reason, the stability of the catalyst acid is a problem, and if the interval from exposure to PEB becomes long, it becomes impossible to form a T-top or form a pattern due to the influence of impurities in the air. Therefore, a so-called environmentally-stable resist is required, and the most promising ones are hydroxystyrene and (meth) acrylic acid esters which are easily decomposed by a photoacid generator (PAG) to generate a carboxylic acid, such as alkyl methacrylate. Are attracting attention.
However, since the conventional copolymer is manufactured by a thermal polymerization method, it is inevitable that unreacted monomers, low molecular weight substances,
Also obtained in the form of a mixture containing a homopolymer of each component,
Therefore, it was impossible to obtain a narrowly dispersed copolymer having a structure as set.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a (meth) acrylic compound which is monomodal, has a narrow molecular weight distribution, and has a controlled structure, and is easily decomposed by alkenylphenol and PAG to produce a carboxylic acid. An object of the present invention is to provide a copolymer with an acid ester and a method for producing the copolymer.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a compound in which the phenolic hydroxyl group of alkenylphenol is protected by a living anionic polymerization method with a saturated aliphatic protecting group alone. After polymerization or copolymerization with a vinyl aromatic compound, block copolymerization is carried out with (meth) acrylates which easily decompose by PAG to generate carboxylic acid, and further, a specific (meth) acrylate is copolymerized. Polymerization, and then the action of an acidic reagent causes only the saturated aliphatic protecting group to be eliminated, thereby blocking the alkenylphenol having a narrow molecular weight distribution and a controlled structure with the (meth) acrylates. They have found that a copolymer can be produced, and have completed the present invention.

That is, the present invention relates to the compounds represented by the general formulas (I), (II) and (III)

[0007]

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[0008]

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[0009]

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(R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a methyl group; R ₄ represents an optionally substituted alkyl group having 1 to 12 carbon atoms or a heterocyclic group; R ₅ represents a group having 7 to 15 carbon atoms which may have a substituent;
Or an alkyl group having the alicyclic group. ), The number average molecular weight is 1,000 to 50,000, and the ratio of the number average molecular weight (Mn) to the weight average molecular weight (Mw) is Mw / Mn = 1.00 to 1.00.
1.50 and repeating the structural unit of the general formula (I) and [the repeating of the structural unit of the general formula (II) + the general formula (II
Is a narrowly dispersed alkenylphenol-based copolymer having a ratio of 1/9 to 9/1, and a block copolymer.

In addition, an anion polymerization method using an alkali metal or an organic alkali metal as a polymerization initiator is carried out by the general formula (I)
V)

[0012]

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(R ₁ represents a hydrogen atom or a methyl group,
R ₆ represents an alkyl group having 1 to 6 carbon atoms. ), A compound in which the hydroxyl group of the phenol residue is protected by a saturated aliphatic protecting group is homopolymerized or copolymerized with a vinyl aromatic compound;

[0014]

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(R ₂ each independently represents a hydrogen atom or a methyl group, and R ₄ has 1 to 5 carbon atoms which may have a substituent.
12 represents an alkyl group or a heterocyclic group. Block copolymerization with alkyl (meth) acrylates represented by the formula (VI)

[0016]

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(R ₃ each independently represents a hydrogen atom or a methyl group, and R ₅ has 7 to 7 carbon atoms which may have a substituent.
15 represents an alicyclic group or an alkyl group having the alicyclic group. 2. The narrowly dispersed alkenyl phenol according to claim 1, wherein after the copolymerization with the (meth) acrylic acid ester represented by the formula (1), the saturated aliphatic protecting group of the general formula (IV) is eliminated. This is a method for producing a system block copolymer.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Examples of the compound represented by the general formula (IV) used in the present invention include pn-butoxystyrene, p-sec-butoxystyrene, p-tert-butoxystyrene,
-Tert-butoxy-α-methylstyrene, m-te
rt-butoxystyrene, m-tert-butoxy-α
-Methylstyrene and the like, which are used alone or as a mixture of two or more.

As the vinyl aromatic compound, styrene,
Examples include o-methylstyrene, p-methylstyrene, α-methylstyrene, p-tert-butylstyrene, 1,3-butylstyrene, and the like, and these are used alone or as a mixture of two or more.

Examples of the (meth) acrylate represented by the general formula (V) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate and n-methacrylate. Butyl acrylate, n-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isodecyl acrylate, isodecyl methacrylate, isooctyl acrylate, isooctyl methacrylate, lauryl acrylate, lauryl methacrylate, etc. Are exemplified, and the number of carbon atoms is 3
Examples of the (meth) acrylate having an alicyclic group or heterocyclic group of from 7 to 7 include cyclohexyl acrylate,
Cyclohexyl methacrylate, tetrahydrofuranyl acrylate, tetrahydrofuranyl methacrylate,
Examples thereof include tetrahydropyranyl acrylate, tetrahydropyranyl methacrylate, 3-oxocyclohexyl acrylate, and 3-oxocyclohexyl methacrylate, and these are used alone or as a mixture of two or more.

The (meth) acrylate represented by the general formula (VI) includes 1-adamantyl acrylate, 1-adamantyl methacrylate, and 2-methyl-2
-Adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 1-methylene adamantyl acrylate, 1-methylene adamantyl methacrylate,
1-ethylene adamantyl acrylate, 1-ethylene adamantyl methacrylate, 3,7-dimethyl-1-
Adamantyl acrylate, 3,7-dimethyl-1-adamantyl methacrylate, isobornyl acrylate, isobornyl methacrylate, tricyclodecanyl acrylate, tricyclodecanyl methacrylate, norbornane acrylate, norbornane methacrylate, menthyl acrylate, menthyl methacrylate,
Examples include dicyclopentenyl acrylate, dicyclopentenyl methacrylate, and the like.
Used as a mixture of more than one species.

The process for producing a copolymer according to the present invention is characterized in that an alkali metal or an organic alkali metal is used as a polymerization initiator together with a compound represented by the above general formula (IV) and, if necessary, a vinyl aromatic compound to form an anion. After polymerization, the compound represented by the general formula (V) and the compound represented by the general formula (V
Block copolymerization is carried out by successively adding the compounds represented by I). This reaction is usually carried out in an organic solvent under an atmosphere of an inert gas such as nitrogen or argon in the range of -100 ° C to 5 ° C.
It is performed at a temperature of 0 ° C.

Examples of the alkali metal of the polymerization initiator include lithium, sodium, potassium, cesium and the like.
As the organic alkali metal, the alkyl, allylic compound and arylated compound of the alkali metal can be used. As these compounds, ethyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, ethyl sodium, lithium biphenyl, lithium naphthalene, lithium triphenyl, sodium biphenyl, sodium naphthalene, sodium triphenyl, 1,1
-Diphenylhexyllithium, 1,1-diphenyl-
3-methylpentyllithium and the like are exemplified.

Examples of the organic solvent include aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and cyclopentane; aromatic hydrocarbons such as benzene and toluene; diethyl ether; In addition to ethers such as tetrahydrofuran and dioxane, they are used alone or as a mixture of two or more of organic solvents usually used in anionic polymerization such as anisole and hexamethylphosphoramide.

The reaction for removing a saturated aliphatic protecting group from the obtained copolymer to form an alkenylphenol skeleton is carried out by using the solvents exemplified in the above polymerization reaction, alcohols such as methanol and ethanol, acetone, and the like. In the presence of ketones such as methyl ethyl ketone, cellosolves such as ethyl cellosolve, and halogenated hydrocarbons such as carbon tetrachloride, hydrochloric acid, hydrogen chloride gas, sulfuric acid, hydrobromic acid, 1,1,
The reaction can be carried out at room temperature to 150 ° C. using an acidic reagent such as 1-trifluoroacetic acid or p-toluenesulfonic acid as a catalyst. In this reaction, the ester substituent of the (meth) acrylate segment represented by the general formula (V) is changed to the stereochemistry of the bulky ester substituent of the (meth) acrylate segment represented by the general formula (VI). Hydrolysis does not occur due to the hindrance effect, and only the saturated aliphatic protecting group of the compound represented by the general formula (IV) is eliminated. As a result, an alkenylphenol copolymer having a narrow dispersion and a controlled structure according to the present invention is produced.

[0026]

The present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited by the following examples. In the examples, m is the total number of repeating units of alkenylphenol, n is the total number of repeating units obtained by polymerizing the (meth) acrylate represented by the general formula (V), and p is the general formula ( V
The total number of repeating units in which the (meth) acrylic acid ester represented by I) is polymerized is shown.

Example 1 In a nitrogen atmosphere, tetrahydrofuran (hereinafter referred to as T
HF) 35 mmol of n-butyllithium (hereinafter abbreviated as NBL) was added to 1500 g, and the mixture was stirred.
While maintaining at −40 ° C., 1.03 mol of p-tert-butoxystyrene (hereinafter abbreviated as PTBST) was added dropwise over 1 hour, the reaction was further continued for 1 hour, and gas chromatography (hereinafter abbreviated as GC). Indicated that the reaction was complete. At this stage, a small amount was collected from the reaction system and analyzed by gel permeation chromatography (hereinafter abbreviated as GPC) for a solution in which the reaction was stopped with methanol. The PTBST polymer had Mn = 5200, M
It was a monodisperse polymer with w / Mn = 1.08. Next, 1 mol of tert-butyl methacrylate (hereinafter abbreviated as t-BMA) was dropped into the reaction system over 1 hour, and the reaction was further continued for 1 hour, and the completion of the reaction was confirmed by GC. At this stage, when collection and GPC analysis were performed in the same manner as described above, it was a monodisperse polymer having Mn = 9400 and Mw / Mn = 1.12. Next, 0.2 mol of isobornyl methacrylate was added dropwise to the reaction system over 30 minutes, and the reaction was further continued for 1 hour, and the completion of the reaction was confirmed by GC. Next, methanol was added to the reaction system to stop the reaction, the reaction solution was poured into a large amount of methanol to precipitate a polymer, which was filtered, washed, dried at 60 ° C. for 15 hours, and dried to obtain a white powdery polymer. I got The polymerization yield based on the total amount of the monomers used was 99.5%. GPC
Upon analysis, Mn = 10700, Mw / Mn = 1.
Twelve monodispersed polymers. Next, 10 g of the obtained polymer was dissolved in ethanol to make a 30% solution, 3 g of concentrated hydrochloric acid was added, and the reaction was performed at 70 ° C. for 3 hours. Then, the reaction solution was poured into a large amount of water to precipitate the polymer. ,filtration,
After washing, the polymer was dried at 60 ° C. for 5 hours to obtain 8.4 g of a white powdery polymer. In this reaction, the infrared absorption spectrum of the polymer before and after the reaction (hereinafter abbreviated as IR) and ¹³ C NMR (hereinafter simply referred to as NMR) were compared. IR: absorption at 890 cm ^-1 derived from the t-butyl group of polyPTBST (not present in poly-t-BMA) disappeared after the reaction, and broad absorption derived from hydroxyl group was observed at around 3300 cm ^-1 . . NMR: t- of poly PTBST at around 29 ppm
The peak derived from the butyl group disappeared after the reaction, while
In the peak around 27 ppm derived from the t-butyl group of poly-t-BMA, the area ratio to benzene ring carbon did not change before and after the reaction. Further, the acid value of the produced polymer was measured.
The value was almost the same as that of the p-hydroxystyrene homopolymer. When GPC was measured on the produced polymer, it was a monodisperse polymer having Mn = 9000 and Mw / Mn = 1.12. The copolymerization ratio measured by NMR was as follows:
m / n / p = 29/29/6. From the above,
The copolymerization and the subsequent elimination reaction are carried out as set, and a narrowly dispersed alkenylphenol-based block copolymer having p-hydroxystyrene and t-BMA as main constituent segments and having an isobornyl methacrylate segment at a terminal is formed. I confirmed that I did.

Example 2 In a nitrogen atmosphere, NBL was added to 1500 g of THF.
50 mmol was added, and 1 mol of PTBST was added dropwise over 1 hour while maintaining the temperature at -40 ° C with stirring, and the reaction was further continued for 1 hour, and the completion of the reaction was confirmed by GC. The PTBST polymer at this stage has Mn = 3500, Mw /
It was a monodisperse polymer with Mn = 1.10. Next, 0.3 mol of methyl methacrylate, t-BMA were added to the reaction system.
0.3 mol of the mixture was added dropwise over 1 hour.
The reaction was continued for a while, and the completion of the reaction was confirmed by GC. The polymer at this stage has Mn = 5000, Mw / Mn = 1.1
3 was a monodispersed polymer. Next, 0.1 mol of tricyclodecanyl methacrylate was added dropwise to the reaction system over 30 minutes, and the reaction was continued for 1 hour, and the completion of the reaction was confirmed by GC. Next, the reaction solution was prepared in Example. Post-treatment was carried out in the same manner as in Example 1 to obtain a white powdery polymer.
The polymerization yield based on the total amount of the monomers used was 99.0%. GPC analysis of this polymer showed that Mn =
It was a monodisperse polymer having an Mw / Mn of 1.500 and Mw / Mn = 1.13. Next, 10 g of the obtained polymer was dissolved in ethanol, 0.5 g of concentrated sulfuric acid was added, and the reaction was carried out at 60 ° C. for 3 hours. Then, the reaction solution was poured into a large amount of water to precipitate the polymer, followed by filtration. After washing and drying at 60 ° C. for 5 hours, 7.9 g of a white powdery polymer was obtained. In this reaction, the IR and NMR of the polymer before and after the reaction were compared. IR: After the reaction, the absorption at 890 cm ^-1 disappeared, and 3
Broad absorption was observed at around 300 cm ^-1 . NMR: after the reaction, a peak around 29 ppm disappeared, 27
In the peak around ppm and the peak around 50 ppm derived from the methyl group of polymethyl methacrylate, the area ratio to benzene ring carbon did not change before and after. Further, the acid value of the produced polymer is 2.8 KOHm
g / g. In addition, GP
When C was measured, Mn = 4300, Mw / Mn = 1.1.
3, and the copolymerization ratio measured by NMR was m / n
/ P = 20/16/2. From the above, the copolymerization and the subsequent elimination reaction are carried out as set, and a p-hydroxystyrene segment, a methyl methacrylate segment, and a t-BMA segment are used as main constitutional units, and a tricyclodecanyl methacrylate segment is added to a terminal. It was confirmed that a narrow-dispersion block copolymer having the same was produced.

Example 3 In a nitrogen atmosphere, a sodium-kerosene dispersion containing 40 mmol of sodium in 2500 g of THF was added, and the mixture was stirred at -60 ° C. while stirring at a temperature of p-tert.
-Butoxy-α-methylstyrene (hereinafter referred to as PTBMST)
A mixture of 1 mol and 0.2 mol of styrene is
The reaction was continued dropwise for 1 hour, and the reaction was completed by GC. The polymer at this stage is Mn
= 11500 and Mw / Mn = 1.22. Then, 1 mol of tetrahydropyranyl methacrylate was added dropwise to the reaction system over 1 hour, the reaction was further continued for 1 hour, and completion of the reaction was confirmed by GC. The polymer at this stage has Mn = 21000, Mw / Mn =
1.25 was a monodispersed polymer. Then, 0.1 mol of dicyclopentenyl methacrylate was added to the reaction system.
The reaction was added dropwise over 0 minutes, and the reaction was continued for another hour, and the completion of the reaction was confirmed by GC. Next, the reaction solution was prepared in Example. Post-treatment was carried out in the same manner as in Example 1 to obtain a white powdery polymer. The polymerization yield based on the total amount of the monomers used was 9
It was 8.7%. GPC analysis of this polymer showed a monodispersed polymer with Mn = 22000 and Mw / Mn = 1.25. Next, 10 g of the obtained polymer was dissolved in a mixed solvent of ethanol / toluene = 3/1 (weight ratio) to make a 20% solution, 3 g of concentrated hydrochloric acid was added, and the mixture was reacted at 70 ° C. for 3 hours. The liquid was poured into a large amount of water to precipitate a polymer, which was filtered, washed, and dried at 60 ° C. for 5 hours to obtain 8.6 g of a white powdery polymer. In this reaction, the IR and NMR of the polymer before and after the reaction
Were measured and compared. As a result, in the IR, 890c
The absorption at m ^-1 disappeared, a broad absorption was newly observed around 3300 cm ^-1 , and it was confirmed that the peak around 29 ppm disappeared in NMR. Further, the acid value of the produced polymer was 2.3 KOHmg / g. When GPC was measured for the produced polymer, it was a monodisperse polymer having Mn = 19,200 and Mw / Mn = 1.25, and the copolymerization ratio measured by NMR was:
m / n / p = 60/50/5. From the above, the copolymerization and the subsequent elimination reaction were carried out as set, and p
It was confirmed that a narrow-dispersion block copolymer having -hydroxy-α-methylstyrene-styrene segment and tetrahydropyranyl methacrylate segment as main constituent units and having a dicyclopentenyl methacrylate segment at a terminal was produced.

Comparative Example 1 Copolymerization and post-treatment were performed in the same manner as in Example 1 except that the third added copolymer component, isobornyl methacrylate, was not used, and Mn = 9300, Mw / M
A monodisperse copolymer with n = 1.11 was obtained. 10 g of the obtained polymer was dissolved in ethanol, and the elimination reaction to the post-treatment were performed in the same manner as in Example 1 to obtain 6.4 g of a white powdery polymer. In this reaction, IR and NMR of the polymer before and after the reaction were measured. IR: absorption at 890 cm ^-1 disappeared, and new
Broad absorption was observed around cm ^-1 . NMR: After the reaction, a peak around 29 ppm disappeared and 2
In the peak around 7 ppm, the area ratio to benzene ring carbon was reduced to 15% before the reaction. When the acid value of the produced polymer was measured, it was found to be 230 KOHmg / g.
Met. GPC measurement of the resulting polymer showed that the polymer was a monodisperse polymer having Mn = 6200 and Mw / Mn = 1.12. From the above, the copolymerization reaction proceeded as set, and at the time of the elimination reaction, the butoxy group of the polyPTBST segment was completely eliminated as planned.
Most of the ester portion of poly-t-BMA is also hydrolyzed,
P-hydroxystyrene segment as set, t-
No block copolymer consisting of BMA segments was obtained.

Comparative Example 2 Copolymerization and post-treatment were carried out in the same manner as in Example 3 except that the third added component, dicyclopentenyl methacrylate, was not used, and Mn = 21500, Mw /
A monodisperse polymer with Mn = 1.25 was obtained. The obtained polymer was subjected to elimination reaction to post-treatment in the same manner as in Example 3,
6.2 g of a white powdery polymer was obtained. In this reaction, the IR of the polymer before and after the reaction was measured.
90cm absorption of ^-1 disappeared, broad absorption was observed newly around 3300 cm ^-1, also, 1725 cm ^-1
The absorption derived from the ester significantly decreased and became a shoulder, and the absorption derived from a carboxylic acid was newly observed at 1700 cm ^-1 . When the acid value of the produced polymer was measured, it was 218 KOHmg / g. When GPC was measured for the produced polymer, Mn = 1290
0, Mw / Mn = 1.25.
From the above, the copolymerization reaction proceeded as set, and in the elimination reaction, the butoxy group of the polyPTBMST segment was completely eliminated as expected, while the ester portion of the poly-tetrahydropyranyl methacrylate segment was also eliminated. Most are hydrolyzed and p-hydroxy-
No block copolymer comprising an α-methylstyrene-styrene segment and a tetrahydropyranyl methacrylate segment was obtained.

[0032]

EFFECT OF THE INVENTION Copolymer of alkenylphenol having a monomodal, narrow molecular weight distribution and controlled structure, and a (meth) acrylate ester which is easily decomposed by PAG to form a carboxylic acid Thus, a narrowly dispersed alkenylphenol copolymer expected to be used as an excimer laser resist material could be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Matsumoto 12-54, Goi-minamikaigan, Ichihara-shi, Chiba Japan Soda Co., Ltd. Soda Co., Ltd.

Claims (3)

[Claims] 1. A compound of the general formula (I), the general formula (II) and the general formula (III) Embedded image Embedded image (R ₁ , R ₂ , and R ₃ each independently represent a hydrogen atom or a methyl group, and R ₄ has 1 to 5 carbon atoms which may have a substituent.
12 represents an alkyl group or a heterocyclic group;
₅ represents an alicyclic group having 7 to 15 carbon atoms which may have a substituent or an alkyl group having the alicyclic group. ) Having a number average molecular weight of 1,000
~ 50,000, the ratio of the number average molecular weight (Mn) to the weight average molecular weight (Mw) is Mw / Mn = 1.00 to 1.50, and repeating the structural unit of the general formula (I) [General formula (II) The repeating unit of the structural unit of formula (III) + the repeating unit of the general formula (III)] is 1/9 to 9/1. 2. The narrowly dispersed alkenylphenol copolymer according to claim 1, wherein the copolymer according to claim 1 is a block copolymer. 3. An anion polymerization method using an alkali metal or an organic alkali metal as a polymerization initiator by the general formula (IV): (R ₁ represents a hydrogen atom or a methyl group, and R ₆ represents an alkyl group having 1 to 6 carbon atoms.) The hydroxyl group of the phenol residue represented by the above formula is protected by a saturated aliphatic protecting group. The compound is homopolymerized or copolymerized with a vinyl aromatic compound, and then the compound of the general formula (V) (R ₂ each independently represents a hydrogen atom or a methyl group;
₄ represents an alkyl group having 1 to 12 carbon atoms which may have a substituent, or a heterocyclic group. ) (Meta)
Block copolymerization with an acrylic acid alkyl ester is performed, and then the compound represented by the general formula (VI): (R ₃ each independently represents a hydrogen atom or a methyl group;
₅ represents an alicyclic group having 7 to 15 carbon atoms which may have a substituent or an alkyl group having the alicyclic group. 2. The narrowly dispersed alkenyl phenol according to claim 1, wherein after the copolymerization with the (meth) acrylic acid ester represented by the formula (1), the saturated aliphatic protecting group of the general formula (IV) is eliminated. A method for producing a block copolymer.