JPS5996111A - Production of cyclized isoprene polymer - Google Patents

Abstract

PURPOSE:To obtain the titled cyclized polymer excellent in resolution and useful in the production of resist materials, by polymerizing isoprene monomer in the presence of an organometallic compound, and bringing the obtained polymer into contact with a catalyst containing a boron trifluoride/ether complex. CONSTITUTION:Isoprene monomer is dissolved in a polymerization solvent such as benzene and, after adding an organometallic compound of the general formula: RM (wherein R is an alkyl, aryl, or aralkyl and M is LI, Na, or K), e.g., butyllithium, as an initiator for living polymerization, the monomer is polymerized. The produced polymer is brought into contact with a boron trifuoride/ether complex or a catalyst comprising this complex and an organic halide of the formula: R'M (wherein R' is benzyl, t-butyl, or alkyl and X is a halogen), e.g., benzyl chloride, to obtain the titled cyclized polymer having a dispersion as defined by the weight-average MW to number-average MW ratio of below 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the ratio M of the weight average molecular weight tMw to the number average molecular weight MN.
The present invention relates to a method for producing a cyclized imprene polymer having a degree of dispersion defined by wAAN of 2 or less. More specifically, the isoprene monomer is polymerized in the presence of an organometallic compound represented by the general formula RM (R represents an alkyl, aryl, or aralkyl group, and M represents lithium, sodium, or potassium. small polymer,
Boron trifluoride ether complex or this complex and general 2R
'X'(R' represents benzyl, t-butyl or allyl group, X represents halogen. This is the way to do it.

Cyclized products of natural rubber or synthetic rubber are most widely used as raw materials for so-called negative resist materials, which are insolubilized in solvents by crosslinking between polymer chains upon irradiation with light.

Among the properties of resist materials, particularly important ones are sensitivity and resolution, but as the degree of integration of integrated circuits increases, the requirements for resolution have become stricter, and it is now possible to handle microfabrication of 1 μm or less (1 ftlJjl). materials are required.

However, the conventionally used rubber-based resist materials mentioned above have problems in terms of resolution, and are said to have a limit of about 3 to 6 μm, and the dimensional precision below this is considered to be the limit. It is difficult to support the required integrated circuit manufacturing process with a high degree of integration.

The present inventors have arrived at the present invention as a result of intensive research aimed at solving the problems seen in these conventional rubber-based resist materials, especially cyclized isoprene-based polymers.

Conventional rubber-based resist materials, regardless of whether they are natural rubber or synthetic rubber, have a very wide molecular weight distribution, with a weight average molecular weight Mw and a number average molecular 'fi'j: M
The degree of dispersion defined by the ratio Mw/Mx of N usually takes a value of 2 or 3 or more.

The purpose of the present invention is to focus on the molecular weight distribution of these conventional rubber resist materials, and to cyclize an in-prene polymer with a dispersity close to 1 under conditions that do not disrupt its molecular weight and distribution. The objective is to produce a cyclized isogrene polymer with excellent resolution.

The ninth feature of the present invention is that in the cyclization step of an isoprene-based polymer, cyclization can be achieved without substantially disturbing the A''<-uE polymer molecular weight distribution.

From Morai, as a method for cyclizing diene polymers, (1)
Method using sulfuric acid, sulfonic acid, (2) Friedel e-Craft catalyst such as 8nCl, TiC! 14. F
(3) A method using a hydrogen halide, such as an aqueous chloride system, (4) A method using a phosphorus compound, such as phosphorus pentachloride, phosphorus oxychloride, etc., (5) A method using a cationic polymerization initiator, such as diethyl aluminum chloride. Alternatively, a method using a catalyst consisting of ethylaluminum dichloride and trichloroacetic acid is known.

However, in conventional methods, reactions between polymers such as gelation proceed, and it is difficult to selectively achieve intramolecular reactions.

In the present invention, the isoprene monomer is converted to -ff formula RM (R
represents an alkyl, aryl or aralkyl group, M
indicates lithium, sodium or potassium. By living polymerization using an organometallic compound represented by the following as an initiator, a nearly monodisperse isoprene polymer with a degree of dispersion of 1.1 or less is produced, and the polymer is trifluorinated under mild conditions. The degree of dispersion can be increased by bringing the boron ether complex or the complex into contact with a catalyst consisting of an organic halide represented by 2R'X (R/ represents a benzyl, t-butyl, or allyl group, or a halogen). We have found a method for producing an isoprene electroconjugate cyclized product having a molecular weight of 2.0 or less.

Each step will be explained below.

In the process of combining imprene monomer with M, an organometallic compound represented by the general formula RM (R represents an alkyl, aryl, or aralkyl group, and M represents lithium, sodium, or potassium), which is a living polymerization initiator, is used as a living polymerization initiator. For example, butyllithium, sodium naphthalene, sodium anthracene, sodium biphenyl, phenylisopropyl potassium, α-methylstyrene tetramer potassium, etc. can be used, but butyllithium is preferable. Further, the selection of the polymerization solvent is extremely important in relation to the microstructure of the diene polymer to be produced. For example, when n-butyllithium is used as an initiator, hydrocarbon solvents such as hexane, cyclohexane, benzene, toluene, and xynonato are selective to 1.
Although 4-addition polymers are produced, it is known that 1,2- or 4-addition polymers can be produced in ether solvents such as tetrahydrofuran, tetrahydrobilane, and dioxane.

The solvent used in the present invention is -inoprene 1°4-
Hydrocarbon solvents from which addition polymers are selectively obtained, e.g.
Hexane, cyclohexane, benzene, toluene.

Although xylene and the like can be used, benzene, toluene, and xylene are preferably used.

Although there is no need to particularly limit the molecular weight of the inoprene polymer of the present invention, considering that the sensitivity of resist materials made from this polymer depends on the molecular weight, the molecular weight should be j 3000 or more, preferably 20000 or more. It is desirable to set the polymerization conditions so as to satisfy the above conditions.

Next, as a catalyst used in the cyclization step, the cyclization reaction of the polymer will proceed even if only a boron trifluoride ether complex is used, but the reaction system is generally 2R'X (R' is a benzyl, t-butyl or allyl group). or halogen.By coexisting with an organic halide represented by , the reaction is significantly improved. That is, compared to the case where the complex is used alone, the complex and the organic halide are When a catalyst consisting of these is used, the reaction time is shortened and the disturbance in the molecular weight distribution of the resulting polymer cyclized product is suppressed.The organic halides used here include benzyl chloride and t-butyl chloride. , allyl chloride.

Mention may be made of benzyl bromide, t-butyl bromide, allyl bromide, benzyl iodide, t-butyl iodide, and allyl iodide.

Examples of the solvent used in this step include aromatic hydrocarbons such as Eva,
It can reduce 741% of Hensen, toluene, xylene, etc.

The concentration of the isoprene polymer in the cyclization step depends on the molecular weight of the polymer, but it is preferably 0.5% by weight or more and 15% by weight or less, preferably 10% by weight or less. If it exceeds 15% by weight, gelation of the polymer will proceed during the reaction, which is not preferable.

If the concentration of the trifluoroboron ether complex is 1 mol % or more of the number of moles of the monomer of the polymer, this reaction will be carried out repeatedly, but from a practical point of view, It is preferably 6% or more of the unit mole number.

In addition, the organic].logenide used as a cocatalyst is 10 to 500 mol%, preferably 20 to 600 mol% of the complex.
It is mole%. In addition, when carrying out this reaction in the presence of a cocatalyst to produce the polymer cyclized product with a certain cyclization rate, it is possible to reduce the amount of catalyst 2 and to It is possible to save time.

The temperature at which the cyclization reaction is carried out is particularly important in relation to the molecular weight distribution of the resulting polymer cyclization product.

That is, at temperatures below 10°C, the molecule+n1 reaction and gelation proceed, and at temperatures above 80°C, a cyclized product with a wide molecular weight distribution is produced, which is undesirable. Therefore, it is desirable to carry out the cyclization reaction at a temperature of 1 u to 80°C, preferably 20 to 60°C. In addition, in the cyclization reaction step, 0.2
This reaction proceeds without any problem even if alcohols such as methanol, ethanol, etc. and phenol compounds such as BHT are contained as long as the amount is less than % by weight.

That is, in the polymerization process, for example, the polymer obtained by living polymerization of isoprene monomer using benzene as a solvent is added to the polymerization reaction system without forming a monomer.
The above-mentioned cyclization reaction can be achieved without any problem even if a solution containing a terminator such as ethanol and the like is added with a predetermined amount of benzene to adjust the concentration.

There is no need to particularly limit the cyclization rate of the polymer cyclide, but considering that the sensitivity of this resist material depends on the cyclization rate of the polymer cyclide, the cyclization rate should be from 40 to 40. 90%
, preferably 50% to 80%.

According to the present invention, isoprene monomer cyclized products with a narrow molecular weight distribution suitable as raw materials for negative-tone photoresists in the high-snow circuit manufacturing process can be produced in a simple manner under mild conditions.

Next is a real Mli example! - The present invention will be explained in more detail below.

Example 1 Rigorously dehydrated isoprene monomer 529 and benzene 515 are mixed under a vacuum of 10 m + 11 Hg and, without stirring, added to a hexane bath solution of n-butyllithium (a
4.45 ml of iO, 165 mol//) was added dropwise at room temperature.

Thereafter, stirring was continued for an additional 6 hours, and the reaction solution was precipitated in ethanol to recover the polymer. The polymerization rate was 100%. Microstructural NMR of treated isoprene polymer
As a result of evaluation by measurement, it was 1.4-. 44- and 1,
The 2-adducts were 94%, 6% and 0%, respectively.

The molecular weight of the polymer was determined to be 7.6x10' by light scattering measurement.
I was confused. Furthermore, as a result of evaluating the molecular weight distribution using an ultracentrifugal velocity method, the degree of dispersion (reduced w/Ml) was 1002, confirming that the polymer was close to monodisperse.

2v of the polymer was dissolved in 100% of benzene, and 4ml of a benzene solution of boron trifluoride ether complex (concentration 0.44 mo'v/l) was added at 25°C under a nitrogen stream, followed by stirring for 2 hours. . The reaction solution was precipitated in methanol to obtain a powdered isogrene polymer cyclized product. The cyclization rate of the cyclized product was evaluated by NMR measurement and was found to be 52%. However, as a result of evaluating the molecular weight distribution using the ultracentrifugal velocity method, the dispersion W<=φN) was 1.66. Furthermore, no formation of intermolecular reaction products or gels of the isoprene polymer was observed in measurements by gel permeation chromatography (hereinafter abbreviated as GPC).

Examples 2 to 7 A polymerization reaction solution polymerized by the same method as Example 1,
After adding methanol in an amount 5 times the molar amount of the initiator to stop the polymer solution, B of the 5-fold award part was added to the polymer solution for the 100-fold needle part of the polymerization.
Added HT. Add 80 m of benzene to 20 m of the polymer bath solution.
A cyclization reaction was carried out using a solution to which 1 was added. The results are shown in Table-1.

Table 1 Examples 8 to 10 Using a polymer solution prepared in the same manner as in Example 2 using a predetermined amount of butyl thirium, the ring of Example 1 was prepared except that 1.76 mmol of 1-butyl chloride was coexisting. The reaction was carried out in the same manner as the chemical reaction.

The results are shown in Table-2.

Table 2 Examples 11 to 18 Using the isoprene polymer solution polymerized in Example 9, cyclization reactions were carried out under various conditions. The results are shown in Table-3.

Table-3× * BF, 0Et2 was reduced by 6 mol % per 1 unit mol of monomer of the polymer.

Examples 19 to 2p A cyclization reaction was carried out in exactly the same manner as in Example 9 except that another organic halide was used instead of chlorinated t-butyl. The results are shown in Table 4.

Table 4 Comparative Examples 1 to 6 A cyclization reaction was carried out under the same conditions as in Example 9, except that the isoprene polymer solution polymerized in Example 9 was used and the cyclization catalyst was changed.

The results are shown in Table-5.

Table-5 Procedural amendment (method) % formula % 1 Indication of the case 1982 Patent Application No. 206048 2 Name of the invention Process for producing isoprene polymer cyclized product Person making the amendment Telephone number (585) 3311 4 Amendment order Date: February 2, 1982 (Shipping date: February 221, 1982)
6. Specifications subject to amendment 7. Reprint of the description of contents of amendment (no change in content)

Claims (1)

[Claims] (1) Imprene monomer is polymerized in the presence of an organic metal represented by general 2RM (R represents alkyl, aryl, or aralkyl, M represents lithium, sodium, or potassium), and the N polymer is added with boron trifluoride. % or the complex and the general 2 R'X(R'
represents benzyl, t-butyl or allyl group, and X represents halogen. ) A method for producing an isoprene polymer cyclized product having a dispersity defined by the ratio Mw/MN of N Sakaki average molecular weight iMw and number average molecular weight ηN of 2 or less. .