JPH051115A - Production of polyhydroxystyrene - Google Patents

Abstract

PURPOSE:To obtain the polymer useful as a resist material having high resolving power for super LSI, having a narrow molecular weight distribution by subjecting tetrahydropyranyloxystyrene monomer to living anionic polymerization and eliminating tetrahydropyrancyl group. CONSTITUTION:p-Vinylphenol is made to react with dihydropyran in a solvent such as methylene chloride in the presence of pyridinium p-toluenesulfonate at room temperature to give tetrahydropyranyloxystyrene monomer shown by formula I. Then the monomer is polymerized in a solvent such as tetrahydrofuran by using n-butyllithium as an initiator at -78 deg.C to give a living polymer composed of a red solution. The reaction mixture is poured to mehanol, the formed polymer is precipitated, separated and dried to give a polymer consisting of a repeating unit shown by formula II, which is further treated with a small amount of conc. hydrochloric acid at 60 deg.C and tetrahydropyranyl group is eliminated to give the objective polyhydroxystyrene.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for producing a styrene derivative, and more particularly to a method for producing polyhydroxystyrene useful as a functional polymer.

[0002]

2. Description of the Related Art Conventionally, functional polymers have been widely used as high-resolution lithography resist materials used for LSIs. Particularly today, as the density is increased, resist materials are required to have high resolution and high developability. Therefore, in the case of a novolak resin which is a conventional type resist material, the molecular weight is controlled by a method called fractionation to improve the resolution and developability (Japanese Patent Laid-Open No. 12217542/1987). However, the method of separation has a drawback that the operation is complicated and takes time.

Here, it is theoretically known that a resist material having a narrow molecular weight distribution (narrow dispersibility) is preferable as a high-resolution resist material. In addition, the property that the molecular weight can be controlled to an arbitrary value is extremely effective when it is made compatible with other polymers as a polymer blending agent or as a precursor of a copolymer that forms a microphase-separated structure.

Therefore, as a resist material in the future, a styrene derivative whose molecular weight is relatively easy to control is considered to be promising, and polyhydroxystyrene, which is excellent in developability and plasma resistance, is being studied, but it is industrially used. It has not been used yet, and it is not yet known that it can sufficiently follow the demanding performance that becomes severe.

The above-mentioned polyhydroxystyrene has been conventionally synthesized by radical polymerization (Journal of Polymer Science (Part 1), Vol. 7, pages 2175-2.
184 (1969)), and narrowly dispersed polyhydroxystyrene are reported in JP-A-59-199705 and Proceedings of the Society of Polymer Science, Vol. 31, p. 1149.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies on the novel method for synthesizing the polyhydroxystyrene, and as a result, after performing living anionic polymerization of a tetrahydropyranyloxystyrene monomer, the tetrahydropyranyl group is eliminated. The inventors have found that by doing so, it is possible to synthesize polyhydroxystyrene which has a narrow molecular weight distribution and can be controlled to be a polymer having an arbitrary molecular weight, and has reached the present invention.

Therefore, the first object of the present invention is to provide a novel method for producing polyhydroxystyrene useful as a high-resolution resist material and having a narrow molecular weight distribution and capable of controlling a polymer having an arbitrary molecular weight. To do.

A second object of the present invention is to provide a novel method for producing polyhydroxystyrene which has a narrow molecular weight distribution and can be controlled to an arbitrary molecular weight, which is suitable as a polymer blending agent or a precursor of a copolymer. To do.

[0009]

The above objects of the present invention are characterized in that the tetrahydropyranyloxystyrene monomer represented by the following structural formula is subjected to living anionic polymerization and then the tetrahydropyranyl group is eliminated. Was achieved by the method for producing polyhydroxystyrene.

[Chemical 2]

The manufacturing method of the present invention will be described in detail below. In the living anionic polymerization of tetrahydropyranyloxystyrene in the present invention, a known anionic polymerization disclosing agent can be appropriately used, but in particular, n-butyllithium, sec-butyllithium, tert-butyllithium, sodium naphthalene, anthracene. It is preferable to use an organometallic compound such as an organic alkali metal such as sodium, potassium naphthalene, sodium α-methylstyrene tetrameride, cumyl potassium, cumylcesium. By using such an initiator, only the vinyl group of tetrahydropyranyloxystyrene is selectively polymerized.

The above polymerization is preferably carried out in an organic solvent. The organic solvent used in this case is a solvent such as an aromatic hydrocarbon, a cyclic ether, an aliphatic hydrocarbon (for example, benzene, toluene, tetrahydrofuran, dioxane, tetrahydropyran, dimethoxyethane, n-).
Hexane, cyclohexane, etc.), or a mixed solvent thereof.

Tetrahydrofuran is particularly preferred in the present invention. The concentration of the monomer used for the polymerization is 1 to 30.
% Is preferred, and the reaction is preferably carried out under high vacuum or in an atmosphere of an inert gas such as argon or nitrogen, with stirring at a temperature between -78 ° C and the boiling point of the solvent used.
In particular, when a tetrahydrofuran solvent is used, it is -7
Polymerization is preferably carried out at 8 ° C. to 0 ° C. and at room temperature when a benzene solvent is used.

The reaction time is about 10 minutes to 5 hours, and when poly (tetrahydropyranyloxystyrene) has a desired molecular weight, a reaction inhibitor such as methanol, water or methyl bromide is reacted. The reaction is stopped by adding it to the system. Then, the poly (tetrahydropyranyloxystyrene) can be purified and isolated by crystallizing the polymer from the reaction solution in which the reaction has been stopped using a precipitating agent such as methanol and drying.

The molecular weight distribution of the poly (tetrahydropyranyloxystyrene) thus obtained is monodisperse (Mw / Mn = 1.05 to 1.50) and is represented by the following structural unit.

[Chemical 3]

In this case, the average molecular weight Mw can be easily calculated from the amount of the monomer used and the amount of the initiator,
The number average molecular weight Mn can be easily determined using a membrane osmometer.

The yield of the polymer compound in the above polymerization reaction is almost 100% based on the tetrahydropyranyloxystyrene monomer used in the reaction. Therefore, the average molecular weight of the target polymer compound can be easily adjusted by adjusting the weight of the tetrahydropyranyloxystyrene monomer compound used and the number of moles (number of molecules) of the living anion initiator.

The structure of the produced polymer compound was confirmed by infrared absorption (IR) spectrum and ¹ H-NMR.
The molecular weight distribution can be easily evaluated by gel permeation chromatography (GPC).

In the present invention, the following polyhydroxystyrene of interest is obtained by cleaving the ether bond of the tetrahydropyranyl group of the poly (tetrahydropyranyloxystyrene) thus produced.

[Chemical 4]

The ether bond cleavage reaction is carried out by dissolving poly (tetrahydropyranyloxystyrene) in a solvent such as dioxane, acetone, acetonitrile, benzene or a mixed solvent thereof, and then dissolving hydrochloric acid, hydrobromic acid or paratoluene sulfone. It can be easily carried out by dropping an acid such as an acid pyridinium salt. During the above reaction,
Since the main chain of the polymer of poly (tetrahydropyranyloxystyrene) is not cleaved or the intermolecular crosslinking reaction does not occur, it is possible to obtain polyhydroxystyrene having the originally designed molecular weight distribution and molecular weight. it can.

[0020]

As described above in detail, according to the present invention, polyhydroxystyrene useful as a photosensitive polymer material such as a high-resolution resist material necessary for the production of VLSI or as a blending material of polymers. The molecular weight distribution of can be easily narrowed and its molecular weight can be arbitrarily controlled.

[0021]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Example 1.

1.5 mol of dihydropyran with respect to p-vinylphenol was placed in a reaction vessel and reacted in the presence of 0.1 mol of pyridinium p-toluenesulfonate in a methylene chloride solvent at room temperature for 6 hours. It was Next, in order to remove the catalyst in the reaction product, it was washed with a saturated saline solution, and the product was distilled under reduced pressure to obtain tetrahydropyranyloxystyrene in a yield of 85%. The tetrahydropyranyloxystyrene had a boiling point of 120 ° C./0.1 mmHg.

In order to remove impurities such as water from the tetrahydropyranyloxystyrene monomer obtained as described above, it was distilled using CaH ₂ , further purified with purified sodium benzophenone, and then polymerized as follows.

700 ml of tetrahydrofuran as a solvent and 1 n-butyllithium initiator as a solvent in a 1 liter flask.
After charging 10 ³ mol of x10 ^-3 mol, 30 g of the above tetrahydropyranyloxystyrene diluted with 50 ml of tetrahydrofuran was added to the above mixed solution at -78 ° C and polymerized for 1 hour. As a result, this solution turned red. Polymerization was stopped by adding methanol to the reaction solution.

The reaction mixture is then poured into methanol,
After the obtained polymer was precipitated, it was separated and dried.
5 g of white polymer was obtained. ¹ H-NM of the obtained polymer
The result of measuring the R spectrum is as shown in FIG.
The GPC elution curve was as shown in FIG.

From the results of IR spectrum and ¹ H-NMR spectrum, it was confirmed that the tetrahydropyranyl group bonded to the ether had no active terminal remaining and only the vinyl group in the styrene part was reacted. It was The number average molecular weight measured by the membrane osmotic pressure method was 3.0 × 1.
It was 0 ⁴ g / mol. Further, from the results of the GPC elution curve, it was found that the polymer has a very high monodispersity (narrow molecular weight distribution) in terms of molecular weight distribution.

10 g of the tetrahydropyranyloxystyrene obtained as described above was dissolved in 200 ml of acetone, a small amount of concentrated hydrochloric acid was added at 60 ° C., the mixture was stirred for 5 hours, and the reaction solution was poured into hexane to reprecipitate the polymer. Then, it was washed with water and dried.

The weight of the obtained polymer was 6.8 g. Further, it was found from the GPC elution curve (FIG. 3) that the number average molecular weight was 1.8 × 10 ⁴ g / mol, and the obtained polymer had extremely high monodispersity (narrow molecular weight distribution).
It was confirmed to be a polymer.

Furthermore, the peak derived from the tetrahydropyranyloxy group disappeared from the ¹ H-NMR spectrum, and a characteristic absorption band corresponding to polyhydroxystyrene appeared in the IR spectrum. From these results, it was confirmed that the obtained polymer was poly (p-hydroxystyrene) having a narrow molecular weight distribution.

Example 2 1 liter of tetrahydrofuran as a solvent and naphthalene potassium as a polymerization initiator in a 2 liter flask.
Tetrahydropyranyloxystyrene 5 purified in the same manner as in Example 1 was prepared by charging 5 × 10 ⁻⁴ mol.
0 g was added diluted with 100 ml benzene at 25 ° C,
After polymerizing for 3 hours, the solution turned red. The polymerization reaction was stopped by adding methanol to the reaction solution. Next, the reaction mixture was poured into methanol to precipitate the polymer, which was then separated and dried to obtain 24.5 g of white polymer poly (tetrahydropyranyloxystyrene).

IR spectrum and ¹ H of the obtained polymer
When the NMR spectrum was measured, characteristic absorption similar to that of Example 1 was obtained, and the GPC elution curve was very sharp as shown in FIG. 4, and the obtained polymer had a very high monodispersity. Was confirmed. The number average molecular weight of the obtained polymer was 10 × 10 ⁴ g / mol.

10 g of the above poly (tetrahydropyranyloxystyrene) was dissolved in 200 ml of acetone and the temperature was raised to 25 ° C.
After adding a small amount of p-toluenesulfonic acid pyridinium salt with and stirring for 5 hours, the reaction solution was poured into water to reprecipitate the polymer, and washing and drying were performed.

The weight of the obtained polymer was 6.8 g and the number average molecular weight was 5.5 × 10 ⁴ g / mol. Also, GP
Since the C elution curve was sharp as shown in FIG. 5, it was found that the polymer had a very high monodispersity.

The ¹ H-NMR spectrum of the obtained polymer does not show a peak derived from a tetrahydropyranyloxy group, while the IR spectrum shows a characteristic absorption band corresponding to poly (p-hydroxystyrene). It was From these results, it was confirmed that the obtained polymer was poly (p-hydroxystyrene) having a narrow molecular weight distribution.

[Brief description of drawings]

FIG. 1 shows the ¹ H-NMR spectrum of the polymer of Example 1.

FIG. 2 shows the GPC elution curve of the polymer of Example 1.

FIG. 3 shows a GPC elution curve of p-hydroxystyrene obtained in Example 1.

FIG. 4 shows a GPC elution curve of the polymer of Example 2.

FIG. 5 shows a GPC elution curve of p-hydroxystyrene obtained in Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motoyuki Yamada 100-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Kanagawa Science Park R & D Building A 12F Shin-Etsu Chemical Co., Ltd. Corporate Research Center (72) Inventor Fujio Yagihashi 100-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Kanagawa Science Park R & D Building A 12 F Shin-Etsu Chemical Co., Ltd., Corporate Research Center (72) Minoru Takamizawa 100, Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa -1 Kanagawa Science Park R & D Building A 12 F Shin-Etsu Chemical Co., Ltd. Corporate Research Center

Claims (1)

Claims: 1. The following structural formula: A method for producing polyhydroxystyrene characterized in that the tetrahydropyranyloxystyrene monomer represented by is subjected to living anionic polymerization and then the tetrahydropyranyl group is eliminated.