JPH0840751A - Method for manufacturing glass woven fabric for printed wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a method for manufacturing a glass fiber woven fabric that enables a printed wiring board having excellent punching workability and drilling workability. [Structure] A method for producing a glass woven fabric for a printed wiring board, which comprises subjecting a glass woven fabric to a boric acid treatment and then heating the glass woven fabric at a temperature of 200 ° C. or higher to reduce the strength of glass fibers constituting the glass woven fabric.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a glass woven cloth for printed wiring boards, and more particularly to a method for manufacturing a glass woven cloth which provides a printed wiring board having excellent drilling workability.

[0002]

2. Description of the Related Art There are various types of printed wiring boards used in computers, electronic devices, communication devices, etc.
Wiring boards using woven glass cloth as a reinforcing material are mainly used because of their excellent properties. A printed wiring board using glass woven fabric as a reinforcing material is superior to other printed wiring boards in terms of mechanical properties, electrical properties, heat resistance, chemical resistance, etc. Mainly used in the field. However, since the printed wiring board using the woven glass cloth as the reinforcing material also uses the inorganic glass fiber as the reinforcing material,
It has the drawback of poor drilling workability. This has been a problem in the industry for a long time, but recently there has been a strong demand for improvement in drilling workability.

As the density of printed wiring boards increases and the number of layers increases, the demand for circuit reliability becomes severe. One of the demands is for the inner wall roughness of the drill to have even better smoothness. Is becoming more common. In addition, since the density of printed wiring boards and the number of layers have increased, the wiring density of circuits has increased, and the IC and L
Chips such as SI have come to be surface-mounted. As a result, the diameter of the drill hole is becoming smaller, and it is necessary to improve the accuracy of the drill hole position. In addition, in the field of general-purpose products such as double-sided plates, in order to reduce the cost of drilling in response to the demand for cost reduction, the aim is to increase the number of layers to be stacked during drilling, and to study base materials with low drill wear. Has been done. For the above reasons, improvement in drilling workability of a printed wiring board using a glass woven fabric base material has become a big problem.

Various proposals have been made to solve these problems. For example, in Japanese Examined Patent Publication No. 63-5512, a glass karaka cloth is made by heating at high temperature for a long time in a state in which an alkoxysilane compound such as tetraalkoxysilane, trialkoxysilane and dialkoxysilane is attached. A method of reducing the mechanical strength of a woven fabric is disclosed. Printed wiring boards using woven glass fabric treated with alkoxysilanes have been shown to have improved drillability compared to conventional boards. In addition, the applicant of the present invention previously filed Japanese Patent Application No. 63-192.
No. 656, filed a method for reducing the strength of a glass woven fabric by continuously heat treating the glass woven fabric at a high temperature of 500 to 800 ° C.

According to Japanese Examined Patent Publication No. 63-5512, a method of heating a glass woven cloth treated with an alkoxysilane at a high temperature for a long time is adopted. For example, 400 ° C. in the embodiment,
An example of 20 hours is shown. The necessity of heating at such a high temperature for a long time has a problem in terms of energy cost and process control. Japanese Patent Application No. Sho 63-192656
Similarly, in the case of, since a high temperature of 500 to 800 ° C. is used, there is a problem that dedicated equipment for high temperature processing is required.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a glass woven fabric which enables a printed wiring board having good drilling workability while maintaining heat resistance and electrical characteristics.

[0007]

DISCLOSURE OF THE INVENTION According to the present invention, a glass woven fabric for printed wiring boards, which is treated with boric acid and then heated at a temperature of 200 ° C. or more to reduce the tensile strength of the glass fibers constituting the glass woven fabric. It is intended to solve the above-mentioned problems by using a woven fabric manufacturing method. A glass woven cloth is dipped in an aqueous solution of boric acid, squeezed with a mangle and dried. The adhesion rate of boric acid to the glass woven fabric is 0.1
It is 1.0%. If the adhesion rate is less than this range,
The strength of the glass woven cloth is not sufficiently reduced and good drilling workability cannot be obtained. When it is larger than this range, the mechanical strength of the glass woven fabric is excessively lowered, and problems such as surface treatment in a later step and cutting of the woven fabric at the time of prepreg occur. The squeezed glass woven fabric is dried. Drying temperature is 100-17
It is appropriately selected in the range of 0 ° C. depending on the drying speed, the kind of glass woven cloth and the like. Also, the drying time is appropriately selected within the range of 20 seconds to 10 minutes.

The dried woven glass cloth is heated at a temperature of 200 ° C. or higher. The heating time can be determined according to the temperature and the attachment rate of boric acid, and according to the required degree of strength reduction. As the boric acid, trimethyl boric acid or a compound such as triethyl boric acid which can be dissolved in water and hydrolyzed to form boric acid can be used. The glass woven fabric used in the present invention is preferably deoiled, but is not necessarily limited thereto. Moreover, as the glass fiber used, E glass fiber, S glass fiber, and D glass fiber can be used. The weave structure of the glass woven fabric may be any weave structure such as plain weave, twill weave, and satin weave, and is not particularly limited.

The tensile strength of the glass woven fabric treated with boric acid of the present invention is reduced to 5% to 15% when the original glass woven fabric which has not been deoiled is 100. This value can be arbitrarily selected depending on the attachment rate of boric acid and heating conditions. If this value is too low, the workability in the surface treatment step or the prepreg step, which is a post step, will be inconvenient, and if it is too high, the effect will be insufficient. The boric acid-treated glass woven fabric is then subjected to a surface treatment with a usual surface treatment agent and provided as a glass woven fabric for a printed wiring board. The silane coupling agent used for the surface treatment is γ-glycidoxypropyltrimethoxysilane, γ
-Methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, N-β-
(N-Vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane-hydrochloride, N-phenyl-γ-
Aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, β- (3,
4-epoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned, and they are appropriately selected depending on the type of resin used. Generally, the tensile strength of glass woven fabric is 2 times that of the original tensile strength by deoiling treatment by ordinary heating.
Although it is reduced to 0 to 30%, it is recovered to about 40 to 60% by the surface treatment with a silane-based surface treatment agent. Also in the case of the present invention, the surface treatment recovers about 20% to 30%.

[0010]

Function: Glass fiber is a kind of tempered glass and has a very high strength as compared with plate glass. This is because when the glass fiber is spun, it is suddenly abruptly increased from a few thousand degrees to room temperature, and a large compressive stress remains on the surface. The reason why the boric acid-treated glass woven fabric of the present invention shows a large decrease in strength is that boric acid adhering to the glass fiber surface is dehydrated and condensed by heating, resulting in boric oxide (B ₂
It forms a thin film of O ₃ ). It is considered that some of them are also condensed with OH groups on the glass fiber surface to generate tensile stress that cancels the compressive stress remaining on the glass surface. By reducing the strength of the glass fiber within a certain range, the hole forming workability of the printed wiring board reinforced with the glass fiber is improved, and the hole forming process can be performed by the punching method. Also, the inner wall roughness of the hole by the drill method becomes good,
Through-hole A printed wiring board with high reliability can be obtained.

[0011]

[Examples] Glass woven cloth Deoiled WEA18W [manufactured by Nitto Boseki Co., Ltd.] Threads used Both warp and weft ECG75 1/0 density Warp 44 / 25mm Weft 34 / 25mm Mass 215g / m ² Dip them in 0.5%, 1.0%, and 2.0% boric acid aqueous solutions, squeeze with a mangle so that the pickup amount becomes 20%, and dry at 110 ° C for 5 minutes.
Three types of boric acid treated glass woven fabrics were obtained. The three types of glass woven fabrics treated with boric acid and the glass woven fabrics not treated with boric acid were heat-treated under the following conditions. 110 ° C./5 min 200 ° C./2 hr 400 ° C./2 hr heat-treated glass woven fabric is treated with a 1% aqueous solution of a cationic silane coupling agent SZ-6032 (manufactured by Toray Silicone Co., Ltd.), 110 ° C., 5 min Then, it was dried and the tensile strength was measured. The results of tensile strength are shown in Table 1.

[0012]

[Table 1]

FR the glass woven fabric surface-treated with
-4 type epoxy resin varnish is impregnated to make a prepreg, 8 sheets of this prepreg are piled up, 170 ° C., 90 mi
It heat-pressed on condition of n, and obtained the laminated board of thickness 1.6mm. The bending strength of this laminate was measured, and the results are shown in Table 2. Similarly, the solder heat resistance and insulation resistance of the laminated plate were measured, punching was performed, punching was performed, drilling was performed, and the state of the inner wall of the drill hole was observed. The results are shown in Tables 3 and 4, respectively. It shows in Table 5.

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

[0017]

[Table 5]

[0018]

The printed wiring board having a glass woven fabric as a base material, which is obtained by the manufacturing method of the present invention, has excellent punching workability and drilling as compared with a conventional printed wiring board having a glass woven fabric as a base material. It is possible to obtain a substrate that has workability and has good through-hole reliability. Further, the number of drilling processes can be increased, and the drilling cost can be reduced.

Claims (1)

[Claims] 1. A glass woven fabric for a printed wiring board, which is obtained by treating a glass woven fabric with boric acid and then heating it at a temperature of 200 ° C. or higher to reduce the tensile strength of glass fibers constituting the glass woven fabric. Production method.