JP2006104347A - Method for producing p-hydroxystyrene-based polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a p-hydroxystyrene-based polymer, by which the p-hydroxystyrene-based polymer can simply be produced in a short time in a simple post treatment without causing a side reaction after the removal of a protecting groups. <P>SOLUTION: This method for producing the polymer containing p-hydroxystyrene-originated constituting units is characterized by dissolving or dispersing a polymer containing p-(1-ethoxyethoxy)styrene-originated constituting units in an organic solvent containing an alcohol in an amount of ≤90 wt.% and then selectively removing the 1-ethoxyethoxy groups with water and hydrochloric acid. By the production method, the 1-ethoxyethoxy groups can be released in the presence of small amounts of the water and the hydrochloric acid at a low temperature and in a short time without decomposing the ester skeletons in other constituting units. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a p-hydroxystyrene polymer. More specifically, by using p- (1-ethoxyethoxy) styrene, it is possible to selectively deprotect only the structural unit derived from p- (1-ethoxyethoxy) styrene with an acid. The present invention relates to a method for producing a styrene polymer.

With the recent high integration and high speed of LSI, fine pattern formation is required for the photoresist used in the lithographic process. Polymers of alkenylphenols such as poly-p-hydroxystyrene used in the lithographic process are used as useful chemical amplification resist materials, but copolymerize with various monomers such as acrylate and styrene. Thus, studies have been made to increase the resolution and developability.
Conventionally, in the production of a p-hydroxystyrene polymer, since p-hydroxystyrene is unstable and a phenolic hydroxyl group inhibits polymerization, it is necessary to polymerize a monomer in which the hydroxyl group is previously protected with a protecting group. Specifically, (1) p- (t-butoxy) styrene, (2) p-acetoxystyrene and other protective monomers are used to polymerize these monomers to obtain a polymer, and then the protective group is removed. A protection method has been employed (see Patent Documents 1 and 2).

In the method of (1) above, in order to deprotect the protecting group of p- (t-butoxy) styrene unit, it is necessary to react at 50 to 70 ° C. for 5 to 10 hours under an acid catalyst. In the case of a copolymer obtained by copolymerizing a monomer having a dissociable group, there is a drawback that the acid dissociable group is also deprotected.
In the method (2), since the protecting group of the p-acetoxystyrene unit is deprotected with a base catalyst, the acid-dissociable group is not deprotected as in (1), but alcohol exists at 50 to 70 ° C. It is necessary to react for the next 5 to 15 hours. Moreover, when a (meth) acrylic acid unit is contained in a polymerization system, there exists a fault that a base catalyst will make a salt.
On the other hand, a method for producing poly (p-hydroxystyrene) is also proposed in which p-methoxymethoxystyrene is subjected to living anion polymerization and then the methoxymethoxy group is deprotected (Patent Document 3). However, in the examples in this specification, it is not necessarily industrially advantageous as it is described that the deprotection reaction of methoxymethoxy group using hydrochloric acid is stirred at 60 ° C. for 8 hours. .
Furthermore, Patent Document 4 describes an example in which a deprotection reaction is performed with oxalic acid after obtaining a copolymer using p-ethoxyethoxystyrene, but this also takes 20 hours to complete the reaction. It takes time and cannot be said to be industrially advantageous.

Japanese Patent Laid-Open No. 05-132513 Japanese Patent Publication No. 07-096569 Japanese Patent Laid-Open No. 06-032818 JP 2002-234910 A

  For the reasons described above, an object of the present invention is to provide a p-hydroxystyrene-based polymer that does not cause a side reaction by deprotection, completes the deprotection reaction in a short time, and is simple in post-treatment after deprotection. It is to provide a manufacturing method.

As a result of diligent research to solve the above problems, the present inventors have found that a polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is mixed with water in an organic solvent containing 90% by weight or more of alcohol. It has been found that it is possible to selectively deprotect only the 1-ethoxyethoxy group by using hydrochloric acid, and therefore a p-hydroxystyrene polymer is produced without deprotecting the monomer having an acid dissociable group. The present inventors have found that this can be done and have completed the present invention.
That is, the present invention can be achieved by dissolving or dispersing a polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene in an organic solvent containing 90% by weight or more of alcohol and using water and hydrochloric acid. -A method for producing a polymer containing a structural unit derived from p-hydroxystyrene, wherein the ethoxyethoxy group is deprotected.

  By adopting 1-ethoxyethoxy group as a protecting group for p-hydroxystyrene and hydrolyzing in alcohol, deprotection can be completed in a short time with a small amount of hydrochloric acid, and other acid-dissociable groups can be removed. It became possible to obtain a p-hydroxystyrene-based polymer without deprotecting the monomer having it.

（式II中、Ｒ¹は、水素原子、ヒドロキシル基、または直鎖もしくは分岐を有する炭素数１〜２０のアルキル基、シクロアルキル基、アルケニル基、アシル基、アルコキシ基から選ばれた少なくとも一種の基を表す。） Hereinafter, the present invention will be described in detail.
Specific examples of the polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene according to the present invention include, for example, a monomer represented by the following general formula (I) and the following general formula (II): The polymer obtained by superposing | polymerizing the mixture of the monomer which has 1 type, or 2 or more types of the monomer represented by this as a main component is mentioned.

(In Formula II, R ¹ is at least one selected from a hydrogen atom, a hydroxyl group, or a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an acyl group, or an alkoxy group. Represents a group.)

〔式III 中、Ｒ²は水素もしくはメチル基、Ｒ³は−ＣＯＯＲ⁴（Ｒ⁴は、水素原子、直鎖もしくは分岐を有する炭素数１から３０のアルキル基、シクロアルキル基、アルケニル基、ヒドロキシアルキル基から選ばれた少なくとも一種の基を表す。）を表す。〕 Furthermore, as the polymer of the present invention, a monomer represented by the general formula (I), a monomer represented by the general formula (II), and a monomer represented by the following general formula (III) The polymer obtained by superposing | polymerizing the mixture of the monomer which consists of 1 type (s) or 2 or more types of these is mentioned.

[In Formula III, R ² is hydrogen or a methyl group, R ³ is —COOR ⁴ (R ⁴ is a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group, an alkenyl group, a hydroxy group, Represents at least one group selected from alkyl groups). ]

  Examples of the monomer represented by the general formula (II) that can be used in the production of a polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene according to the present invention include styrene, p Examples include-(t-butoxy) styrene and p-acetoxystyrene, but are not particularly limited thereto.

  Examples of the monomer represented by the general formula (III) that can be used for the production of a polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene according to the present invention include, for example, acrylic Acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, octyl acrylate, 2-hydroxyethyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate Alkyl acrylates such as phenyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate; aryl acrylates such as phenyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, Benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate Glycidyl methacrylate Furfuryl methacrylate, alkyl methacrylates, such as tetrahydrofurfuryl methacrylate; but like, but is not particularly limited thereto. These can be used alone or in combination of two or more.

A preferred embodiment of the polymer containing structural units derived from p- (1-ethoxyethoxy) styrene in the present invention is a polymer containing 5% by weight or more of structural units derived from p- (1-ethoxyethoxy) styrene. is there. In addition to the monomers represented by the general formulas (I), (II) and (III), the polymer may be a copolymer of other monomers, and may be a ternary or multi-component copolymer. Even a polymer may be used. Moreover, a well-known method can be employ | adopted about the polymerization method of the polymer, There is no restriction | limiting in particular about polymerization methods, such as radical polymerization, anion polymerization, and cationic polymerization.
Examples of the polymerization initiator include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis (2-methylpropio). Azo compounds such as nate), organic peroxides such as benzoyl peroxide, and organic alkyl compounds such as n-butyllithium. Moreover, the addition amount of an initiator can be suitably selected according to the molecular weight of the target polymer.
Polymerization of the polymer in the present invention can be carried out in various solvents such as tetrahydrofuran, acetone, toluene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc. Then, alcohol solvents such as isopropyl alcohol and propylene glycol monomethyl ether are preferable. The monomer concentration at the time of polymerization is preferably selected from the range of 10 to 60% by weight, and the monomer concentration can be appropriately changed depending on the target molecular weight.

  In the present invention, the deprotection reaction of the 1-ethoxyethoxy group is performed by dissolving or dispersing the polymer in an organic solvent containing 90% by weight or more of an alcohol. Examples of the alcohol include primary alcohols such as methanol, ethanol, 1-propanol, isopropyl alcohol, and butyl alcohol; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene. Glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene Glycol monoethyl ether, propylene glycol monopropyl ether, glycol ether monoalkyl ethers such as propylene glycol monobutyl ether; but the like, propylene glycol monomethyl ether is preferred in view of inter alia deprotection reaction.

The present invention is also characterized in that water and hydrochloric acid are used for the deprotection reaction of the 1-ethoxyethoxy group. Although the deprotection reaction can proceed even if a weak acid such as oxalic acid is used, it takes a long time for the reaction to proceed, which is not industrially advantageous. Further, in an organic solvent containing 90% by weight or more of alcohol, even if a strong acid such as hydrochloric acid is used, the 1-ethoxyethoxy group is deprotected in a short time without hydrolyzing other acid dissociable groups. be able to.
The amount of hydrochloric acid used may be an amount such that deprotection of 1-ethoxyethoxy group is completed in a sufficiently short time and does not hydrolyze other acid-dissociable groups. The amount is preferably 0.01 to 0.1 equivalent, more preferably 0.02 to 0.10 equivalent. Moreover, 1-4 equivalent is preferable with respect to 1 equivalent of 1-ethoxyethoxy groups, and, as for the usage-amount of water, 2-4 equivalent is more preferable.
By adopting the above conditions, the deprotection reaction of the 1-ethoxyethoxy group can proceed at a moderate temperature of about 25 to 40 ° C. Although depending on the scale of the reaction system, the reaction can be completed in about 1 to 3 hours, and a polymer containing the target structural unit derived from p-hydroxystyrene can be obtained. The completion of the deprotection can be confirmed by disappearance of the methine peak of p- (1-ethoxyethoxy) styrene, which is seen in the vicinity of 5.3 ppm by proton nuclear magnetic resonance spectrum ( ¹ H-NMR) measurement.

Hereinafter, the present invention will be described more specifically with reference to examples and the like, but the present invention is not limited to these examples and the like.
The molecular weight, molecular weight distribution, and polymerization rate were measured by gel permeation chromatography (GPC) equipped with an RI detector under the following conditions, and calculated from the results. The completion of elimination of the 1-ethoxyethoxy group was confirmed by ¹ H-NMR, and the presence or absence of deprotection of other ester sites was confirmed by the infrared absorption spectrum (IR) measurement under the following conditions.
[GPC]
Equipment used: Shodex GPC-101 [manufactured by Showa Denko KK]
Column: KF-G-KF-805-KF-803-KF-802 [manufactured by Showa Denko KK]
Eluent: Tetrahydrofuran (THF)
Flow rate: 1 ml / min.
Liquid temperature: 35 ° C
[NMR]
Equipment used: AL-400 400 MHz, manufactured by JEOL Ltd.
Solvent: d-DMSO
[IR]
KBr method Device used: JASCO Corporation, FT / IR-420

[Example 1]
In a 1 liter reaction vessel equipped with a stirrer, a cooling tube and a nitrogen bubbling tube, 50.0 g of p- (1-ethoxyethoxy) styrene as a polymerization monomer, 45.8 g of p- (t-butoxy) styrene, and t-butyl methacrylate 73 .9 g, 254.6 g of propylene glycol monomethyl ether as a solvent and 10.2 g of 2,2′-azobis (isobutyronitrile) as a polymerization initiator, heated to 80 ° C. under nitrogen bubbling, and polymerized for 6 hours Went. As a result, the obtained copolymer had a weight average molecular weight of 11,000 and a molecular weight distribution of 2.31.
254.6 g of propylene glycol monomethyl ether and 17.7 g of water were added to the resulting polymerization solution, and 1.4 g of 35% hydrochloric acid (0.05 mol equivalent to p- (1-ethoxyethoxy) styrene) at 30 ° C. Was dripped.
One hour after the dropping, the methine peak of p- (1-ethoxyethoxy) styrene seen in the vicinity of 5.3 ppm by proton nuclear magnetic resonance spectrum measurement disappeared, and the deprotection reaction was completed, and t- It was confirmed that butoxy and t-butyl groups were not eliminated.

[Example 2]
In a 1 liter reaction vessel equipped with a stirrer, a cooling tube, and a nitrogen bubbling tube, 50.0 g of p- (1-ethoxyethoxy) styrene as a polymerization monomer, 45.8 g of p- (t-butoxy) styrene, and t-butyl methacrylate 37 0.0 g, 11.2 g of methacrylic acid, 216.0 g of propylene glycol monomethyl ether as a solvent, and 8.6 g of 2,2′-azobis (isobutyronitrile) as a polymerization initiator up to 80 ° C. under nitrogen bubbling The temperature was raised and polymerization was carried out for 6 hours. As a result, the obtained copolymer had a weight average molecular weight of 12900 and a molecular weight distribution of 2.33.
Propylene glycol monomethyl ether (164.2 g), methanol (95.1 g), and water (17.7 g) were added to the resulting polymerization solution, and at 30 ° C., 35% hydrochloric acid (1.4 g) (p- (1-ethoxyethoxy) styrene was reduced to 0.000). 05 mole equivalent) was added dropwise. One hour after the dropping, the methine peak of p- (1-ethoxyethoxy) styrene, which was observed at around 5.3 ppm by proton nuclear magnetic resonance spectrum measurement, disappeared, and the deprotection reaction was completed, t-butoxy It was confirmed that the t-butyl group was not eliminated.

Example 3
In a 1 liter reaction vessel containing a stirrer, 450.0 g of tetrahydrofuran as a solvent was charged and cooled to −60 ° C., and then 8.6 g of butyl lithium as a reaction initiator was charged, and p- (1-ethoxyethoxy as a polymerization monomer). ) A mixed liquid of 120.5 g of styrene, 25.73 g of p- (t-butoxy) styrene, and 4.22 g of styrene was dropped. Ten minutes after the dropping, 0.5 g of methanol was charged and the reaction was terminated. As a result, the obtained copolymer had a weight average molecular weight of 12400 and a molecular weight distribution of 1.08. The obtained polymerization liquid was distilled off under reduced pressure at 40 ° C., 300 g of tetrahydrofuran was distilled off, and 450.0 g of propylene glycol monomethyl ether was charged. Again, 40 g of the solvent was distilled off under reduced pressure, 150 g of tetrahydrofuran was distilled off, and 34.0 g of water was added to this substitution polymerization solution, and at 30 ° C., 5.2 g of 35% hydrochloric acid (based on p- (1-ethoxyethoxy) styrene). 0.1 molar equivalent) was added dropwise. One hour after the dropping, the methine peak of p- (1-ethoxyethoxy) styrene, which was observed at around 5.3 ppm by proton nuclear magnetic resonance spectrum measurement, disappeared, and the deprotection reaction was completed, t-butoxy It was confirmed that was not detached.

Example 4
Into a 1 liter reaction vessel containing a stirrer, 450.0 g of tetrahydrofuran as a solvent was charged and cooled to −40 ° C., and then 8.6 g of butyl lithium as a polymerization initiator was charged, and p- (1-ethoxyethoxy as a polymerization monomer). ) A mixed solution of 93.10 g of styrene and 56.90 g of p- (t-butoxy) styrene was dropped. Ten minutes after the dropping, 0.5 g of methanol was added to complete the reaction. As a result, the obtained copolymer had a weight average molecular weight of 12400 and a molecular weight distribution of 1.08.
The obtained polymerization liquid was distilled off under reduced pressure at 40 ° C., 300 g of tetrahydrofuran was distilled off, and 600.0 g of propylene glycol monomethyl ether was charged. Distillation under reduced pressure was again performed at 40 ° C., 150 g of tetrahydrofuran was distilled off, 34.0 g of water was charged into this substitution polymerization solution, and 5.05 g of 35% hydrochloric acid at 30 ° C. (based on p- (1-ethoxyethoxy) styrene). 0.1 molar equivalent) was added dropwise. One hour after the dropping, the methine peak of p- (1-ethoxyethoxy) styrene seen in the vicinity of 5.3 ppm by proton nuclear magnetic resonance spectrum measurement disappeared, and the deprotection reaction was completed. It was confirmed that it was not detached.
The composition ratio (molar ratio) of the obtained polymer was p-hydroxystyrene: styrene = 60: 40, which was consistent with the charged composition ratio.

[Comparative Example 1]
In a 1 liter reaction vessel equipped with a stirrer, a cooling tube, and a nitrogen bubbling tube, 140.8 g of p- (t-butoxy) styrene as a polymerization monomer, 28.4 g of t-butyl methacrylate, and 253.6 g of propylene glycol monomethyl ether as a solvent Then, 9.7 g of 2,2′-azobis (isobutyronitrile) as a polymerization initiator was charged, the temperature was raised to 80 ° C. under nitrogen bubbling, and polymerization was performed for 6 hours. As a result, the obtained copolymer had a weight average molecular weight of 12100 and a molecular weight distribution of 2.21. The obtained polymerization solution was charged with 403.5 g of propylene glycol monomethyl ether and 91.8 g of 35% hydrochloric acid, and after 6 hours at 60 ° C. in a sealed state, the peak of the butoxy group ether bond near 900 cm ⁻¹ disappeared completely by IR. This confirmed the completion of the reaction. However, the proton nuclear magnetic resonance spectrum measurement reduced the t-butyl group peak of t-butyl methacrylate and confirmed the elimination of the t-butyl group.

[Comparative Example 2]
In a 1 liter reaction vessel containing a stirrer, 450.0 g of tetrahydrofuran as a solvent was charged and cooled to −40 ° C., and then 8.6 g of butyl lithium as a reaction initiator was charged, and p- (1-ethoxyethoxy as a polymerization monomer). ) A mixed liquid of 93.10 g of styrene and 56.90 g of p- (t-butoxy) styrene was dropped. Ten minutes after the dropping, 0.5 g of methanol was added to complete the reaction. As a result, the obtained copolymer had a weight average molecular weight of 12400 and a molecular weight distribution of 1.08. The obtained polymerization liquid was distilled off under reduced pressure at 40 ° C., 300 g of tetrahydrofuran was distilled off, and 600.0 g of propylene glycol monomethyl ether was charged. Into this substitution polymerization liquid (solvent weight ratio: tetrahydrofuran: 20%, propylene glycol monomethyl ether: 80%), 34.0 g of water was charged, and at 30 ° C., 5.05 g of 35% hydrochloric acid (based on p- (1-ethoxyethoxy) styrene). 0.1 molar equivalent) was added dropwise. One hour after the dropping, the methine peak of p- (1-ethoxyethoxy) styrene, which was observed at around 5.3 ppm by proton nuclear magnetic resonance spectrum measurement, did not disappear, and the deprotection reaction was not completed.

  According to the present invention, a polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is dissolved or dispersed in a solvent containing 90% by weight or more of alcohol, and 1-ethoxy is obtained by using water and hydrochloric acid. A method for producing a polymer containing a structural unit derived from p-hydroxystyrene by selectively deprotecting an ethoxy group can be provided, and the polymer is useful as a chemically amplified photoresist in a lithography process.

Claims (8)

  A polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is dissolved or dispersed in an organic solvent containing 90% by weight or more of alcohol, and 1-ethoxyethoxy group is formed by using water and hydrochloric acid. A method for producing a polymer containing a structural unit derived from p-hydroxystyrene, which is deprotected. A polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is a monomer represented by the following general formula (I) and a monomer represented by the following general formula (II): The production of a polymer containing a structural unit derived from p-hydroxystyrene according to claim 1, wherein the polymer is obtained by polymerizing a seed or a mixture of monomers mainly composed of two or more kinds. Method.

(In Formula II, R ¹ is at least one selected from a hydrogen atom, a hydroxyl group, or a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an acyl group, or an alkoxy group. Represents a group.) A polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is a monomer represented by general formula (I), a monomer represented by general formula (II), and the following general formula: It is obtained by polymerizing a monomer mixture consisting of one or more of the monomers represented by (III) and derived from p-hydroxystyrene according to claim 1 A method for producing a polymer containing a structural unit.

[In Formula III, R ² is hydrogen or a methyl group, R ³ is —COOR ⁴ (R ⁴ is a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group, an alkenyl group, a hydroxy group, Represents at least one group selected from alkyl groups). ]   The composition derived from p-hydroxystyrene according to any one of claims 1 to 3, wherein the alcohol is one or more selected from alcohols having 1 to 4 carbon atoms and glycol ethers. A method for producing a polymer containing units.   5. The amount of water used for deprotection is 1 to 4 equivalents per 1 equivalent of structural units derived from p- (1-ethoxyethoxy) styrene. 5. The manufacturing method containing the structural unit derived from p-hydroxy styrene of description.   The amount of hydrochloric acid used for deprotection is 0.01 to 0.1 equivalent to 1 equivalent of a structural unit derived from p- (1-ethoxyethoxy) styrene. A method for producing a polymer containing the structural unit derived from p-hydroxystyrene according to claim 1.   The polymer containing a structural unit derived from p- (1-ethoxyethoxy) styrene is a polymer having 5% by weight or more of a structural unit derived from p- (1-ethoxyethoxy) styrene. The manufacturing method of the polymer containing the structural unit derived from p-hydroxystyrene of any one of 1-6.   The average molecular weight of the polymer containing the structural unit derived from p- (1-ethoxyethoxy) styrene is 2000 to 30000, derived from p-hydroxystyrene according to any one of claims 1 to 7. A method for producing a polymer containing a structural unit.