JPS5958053A - Silicone resin solution and its preparation - Google Patents

Abstract

PURPOSE:To prepare a silicone resin solution useful as an insulating material for circuit layers such as semiconductors having improved shelf stability from which a very small amount of hydrochloric acid is removed, etc., by dissolving a polycondensate obtained by hydrolyzing a tetra-alkoxysilane and subjecting it to polycondensation in a specific organic solvent, treating it under reduced pressure. CONSTITUTION:A polycondensate obtained by hydrolyzing a tetra-alkoxysilane and subjecting it to polycondensation is dissolved in an organic solvent having >=110 deg.C boiling point, and treated under reduced pressure at <=5mm.Hg, preferably <=3mm.Hg, to give a resin solution having <=10ppm content of a hydrogen halide. The treatment under reduced pressure is carried out at <=40 deg.C, preferably at 5- 28 deg.C.

Description

[Detailed Description of the Invention] (]) Technical Field of the Invention The present invention relates to a silicone resin solution for coating and a method for producing the same, and more specifically, it can be used particularly as a protection material for semiconductors, bubble memories, etc. or as an interlayer insulating material for wiring. , relates to a spin-codable silicone resin and a method for producing the same.

(2) Technical Background, Prior Art, and Problems A solution of a hydrolyzed condensation polymer of alkoxysilane (hereinafter simply referred to as PDAS) is coated and heat-treated at S10. For example, it is used as an insulating material on the surface of semiconductor materials or between wiring layers.

Semiconductor or bubble metal devices are required to have a high degree of long-term reliability, and even if there is a trace amount of impurity in the insulating material used in the equipment, electrolytic corrosion defects will occur. It can cause

Furthermore, when used to protect thin films such as Te and permalloy Fe2O3 that are easily corroded by acids, the inclusion of a small amount of acid may be fatal. Therefore, the presence of even a trace amount of acid in the insulating material is not allowed.

Trace amounts of acid are present in the reaction steps described below.

That is, the tetraalkoxysilane 5l (O
R)4 [wherein R is an alkyl group] A hydrolysis condensation polymer solution of D is generally obtained according to the reaction of the following formulas (1) and (2): Si(OR)4+2H20→ Si(OR) z (OH)! +2ROM
(])ns i (OR)1 (OB) 2→0H
-(=St(OR), O+H+(n-1)H,O(2)
In addition to the reaction of formula (2), a membrane alcohol condensation reaction can also be obtained.

The polymer obtained by Towara's reaction contains many 5i-OH groups in addition to 5t-OR groups, so even the 1\ group is likely to cause a three-dimensional crosslinking reaction, so the reaction must be carried out in an alcohol solvent. Furthermore, equation (1) or (2)
0.05 to the silane monomer as a promoter for the reaction of formula
~05% acid is added. As the acid, hydrochloric acid, which can be removed by volatilization during heat treatment of the coating film, is often used. It appears that most of this hydrochloric acid has been evaporated and removed.
No corrosion of aluminum is observed even when applied directly onto aluminum wiring. However, when a long-term bias test was conducted, it was found that electrolytic corrosion defects occurred.

This was thought to be due to trace amounts of hydrochloric acid that could not be removed. This is because removing as much hydrochloric acid from the resin liquid as possible reduced electrolytic corrosion defects.

Generally, water-soluble impurities in the resin liquid are removed by washing with water. However, in the case of PDAS solution, it is difficult to fidget. Why is it that the 5i-OR group in PDAS is 5i-
It easily converts into OH groups, and when the amount of 5iOH increases, it turns into a gel.It loses its storage stability and turns into a gel. or,
This is because PDAS is distributed in the washing water layer, probably due to the organic solvent that dissolves in the water during washing to remove hydrochloric acid. When a water-miscible solvent such as ethanol is used as a liquid solvent, washing with water itself is impossible and gelation occurs immediately. PDA is mixed with water such as benzene.
It cannot be used because it does not dissolve S. Also, to remove volatile impurities, for example, when the solvent is aged (7 degrees Celsius, heating and distillation separation is used, but this method is also PI).
Not applicable to AS solutions. This is because as the molecular weight increases, it becomes easier to form a gelatin.

PDAS is thus unstable when used alone and gels and dissolves in a short period of time, so it must always be in a state of being dissolved in the visible solvent. The solvent must also have a vapor pressure such that a large amount remains after the hydrochloric acid is removed.

(3) Object and Structure of the Invention The object of the present invention is to provide a silicone resin solution that eliminates the conventional interruption point, removes trace amounts of hydrochloric acid, and is stable in storage, and a method for producing the same. shall be.

In other words, the silicone resin solution of the present invention has a lung point of 110
A hydrolyzed condensate of tetraalkoxysilane is dissolved in an organic solvent having a temperature of 1°C or higher to reduce the content of potassium and hydrogen halide to 1.
7 is special if it is 0 ppm or less, and a method for producing a silicone resin solution in another invention involves mixing a hydrolyzed condensation polymer clear liquid of tetraalcodisilane with an organic solvent having a boiling point of 110° C. or higher. The special feature is that the decompression treatment is performed under a pressure of 5 mmHg or less.

As the organic solvent used in the present invention, any solvent can be used as long as it dissolves PDAS and has a boiling point of 110° C. or higher, such as alcohol, cellosolve acetate, ketone, ether thread, and cellosolve.

For example, n-butanol (117.7°C), n-I
Z alcohol (138,3℃), n-hexanol
.

(157,9℃), n-butyl ether (140,9℃
), shrimp chlorohydrin (117°C), methyl-〇-butyl ketone (127.2°C), and methyl cellosolve acetate (144.5-345.1°C). It is not at all incorrect to say that a solvent with a high boiling point has a low evaporation rate at room temperature. It is advantageous to use a solvent with a high boiling point as the solvent used in the present invention. For example, when comparing methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate, the boiling points are 1445-145.1°C and 15°C, respectively.
6°3°C, 1915°C (Solvent Handbook, edited by Asahara et al.)
Kodansha, Showa 51 weight board), 0.1% H
Solubility of PDAS containing ce in ethyl alcohol solution
When treated under reduced pressure to a level that is undetectable even using silver nitrate, the proportion of cellosolve acetate remaining 1 to the added cellosolve acetate was 48%, 76%, and 76%, respectively.
It was 98%. Of course, it is possible to supplement the swimming fraction by adding it. Solvents with too high a boiling point, such as 2-phenoxyethyl acetate (boiling point 2597
℃) may be advantageous during the first vacuum treatment, but it is possible that the solvent left in the film during coating and curing may form fine cavin holes.

In addition, in the present invention, it is also possible to use a mixed solvent,
For example, λ may be a solvent such as toluene or xylene which cannot dissolve PDAS when used alone, or may be used in combination with an alcoholic solvent such as n-butyl alcohol.

For example, in the case of n-butyl alcohol/xylene-based mixed solvent, it can be used in the # range of 1010 to 8/2 in the type 1 ratio, and in the case of n-butyl alcohol/toluene-based mixed solvent, it can be used in the range of 1010 to 6/4. be able to. However, the range varies somewhat depending on the sum of the PDAS stock solution. Although toluene can cover a wider range than xylene, this is not considered to be because it evaporates more during depressurization treatment.

The pressure during the reduced pressure treatment of the mixed resin solution in the present invention is small; the smaller the pressure, the more advantageous it is because the treatment can be carried out in a shorter time.
IHg or less is preferable. However, 0.05 mg or more can actually be used. If the temperature during the depressurization treatment is high, the treatment can be carried out in a short time, but it is necessary to perform the treatment at a temperature of 40° C. or lower to avoid deterioration of the PDAS. The temperature is preferably 28°C or lower and 5°C or higher.

The required vacuum treatment time depends on the amount of PDAS solution to be treated, P
It varies depending on the concentration of hydrochloric acid contained in the DA8 solution, so it cannot be generally specified, but it is usually 1~10cc for 10cc treatment.
It is 4 hours. The reduced pressure treatment can be carried out using, for example, a four-tally evaporator. In that case, the required processing time varies depending on the angle of the rotary evaporator, the rotation speed, the shape and size of the flask, etc.

By performing the depressurization process in this way, the PDA
It is possible to lower the hydrochloric acid concentration in the S solution to an undetectable level even by using silver nitrate, and it is estimated to be 1 ppm or less. In other words, at least the measurement limit is loppm.
It was not detected by certain analytical methods.

(4) Examples of the invention The present invention will be further explained below with reference to Examples.

Weight average molecular weight (w: converted value to standard polystyrene by gel perfusion chromatography) 5400
, containing 15.5 significant percent of PDAS whose functional groups are ethoxy and silanol in a molar ratio of about 1:1, and the solvent is ethyl alcohol and isopropyl alcohol in a mixing ratio of about 3 by weight: This eggplant-shaped flask containing 845 g of butyl cellosolve acetate was connected to a rotary evaporator and placed at a tilt of 45°C.
It was rotated at a rotation speed of 5 Qrpm. Next, put the flask in a water tank with a bath temperature of 25℃, and use a vacuum pump to 2.0++anHgK.
Acupuncture pressure was applied and wave pressure treatment was applied for 4 hours. 86.1 g of solvent was trapped in a trap using ethanol cooled with dry ice as a refrigerant, and the weight of the solution in the eggplant-shaped flask was 98.
It was 4g. Add 1. butyl cellosolve acetate to this.
'6 g was added to obtain a PDAS solution (■).

When Ig from PDAS solution (2) was taken into a test tube, 0.1% nitric acid aqueous solution 2 was added and stirred, a white gel-like substance eventually adhered to the tube wall in the organic layer, but the water layer The part took on the brownish color of a reduced pottery, but no white precipitate was formed.

The PDAS solution (1) was extracted and washed with water, and quantitative analysis of chlorine was performed. As a result, the concentration of chlorine was less than loppm1, while a total of 1g of PDAS solution T was added to the tube, 01
When one drop of % silver nitrate solution was added and the mixture was shaken, white turbidity occurred.

patent applicant Fujitsu Limited Patent agent Patent attorney Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yukio Uchida Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. A silicone resin solution containing hydrogen halide of 10 ppm or less, which can be obtained by dissolving a hydrolyzed condensation polymer of tetraalkoxysilane in an organic solvent having a boiling point of 110° C. or higher. 2 Hydrolyzed condensation polymer solution of tetraalkoxysilane and 1
Mixing an organic solvent with a boiling point of 10°C or higher, 5III
ff A method for producing a silicone resin solution that is patented in that it is subjected to reduced pressure treatment under a pressure of IHg or less.