JPH07273414A - Glass woven fabric for printed wiring board and printed wiring board - Google Patents

Abstract

(57) [Summary] [Purpose] A glass woven fabric that allows a printed wiring board with less dimensional change in the subsequent process and with substantially equal dimensional change in the warp and weft directions, and as a result, a printed wiring board, and its An object of the present invention is to provide a printed wiring board using a glass woven cloth. [Structure] The warp is an E glass fiber yarn, the weft is an S glass fiber yarn, the weft and the warp have the same count, the ratio of the number of the weft and the warp driven in is 0.65 to 0.80, and the weave design is a plain weave. A glass woven cloth for printed wiring boards, and a printed wiring board using the glass woven cloth as a reinforcing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board used in electronic devices, computers, communication devices, and a glass woven fabric useful as a base material thereof.

[0002]

2. Description of the Related Art Recently, automation has progressed in mounting components on a printed wiring board, and in particular, surface mounting technology for components has progressed, and it has been required to reduce warpage of the printed wiring board and improve dimensional stability. Although various factors affect the occurrence of warpage of the printed wiring board and the dimensional stability, it is said that the characteristics of the glass woven fabric have a great influence especially. Among the printed wiring boards, the composite board is one that has been rapidly increasing in production recently. In the case of a composite plate, warpage and twisting are likely to occur, which is a particularly serious problem. In response to such demands, proposals have been made to change the number of warp yarns and weft yarns of a glass woven fabric, change the weaving shrinkage ratio, and reduce the twist number of yarns. However, none of them have been sufficiently effective.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printed wiring board with less warpage and good dimensional stability, and a glass woven fabric that enables such a printed wiring board.

[0004]

According to the present invention, the warp yarns are E glass fiber yarns, the weft yarns are S glass fiber yarns, the weft yarns and the warp yarns have the same nominal count, and the ratio of the number of the weft yarns and the warp yarns per 25 mm is 0. It is found that the above problem can be solved by using a glass woven fabric for printed wiring boards having a weave design of plain weave. Also, in the above-mentioned glass woven cloth, ECG7
It has been found that the above problems can be solved by using 5 1/0 glass yarns and S glass fibers having a nominal count of 67.5tex as the weft yarns. It was found that the problem can be solved by using a glass woven fabric as a reinforcing material to form a printed wiring board. Examples of the E glass fiber yarn used for the warp of the glass woven fabric of the present invention include the E glass fiber yarn described in JIS R 3413, with a filament diameter of 5 to 11 μm and a yarn count of 5 to 100 tex. Can be used. ECG751 / 0 is also JIS R
3413 is an E glass fiber yarn having a diameter of 9 μm.
About 400 filaments are aligned and twisted. The nominal number of ECG75 1/0 is 67.5t
ex (weight per 1000 m is 67.5 g).

The ECG75 1/0 symbol will be briefly described. E: Glass fiber for electrical insulation C: Continuous fiber G: Filament diameter (G; 9 μm, E; 7 μ)
m, DE; 6 μm, D; 5 μm) 75; Represents glass yarn (in the case of 75, the yarn count is 67.5tex, in the case of 37, 135tex is indicated) 1/0; indicates a single yarn

Further, the glass yarn used as the weft yarn of the glass woven fabric of the present invention is an S glass fiber glass yarn, and the filament diameter and the yarn count are in the same range as the warp yarn. The twist number of the glass yarn used for the glass woven fabric of the present invention is 0.1 to 1.0 times / 25 mm, but a twisted yarn may be used depending on the case.

The above-mentioned glass yarns for warp and weft are spun and wound up by a conventional method. At this time, a sizing agent containing starch or an oil agent is applied in order to obtain the sizing property of the yarn. The wound glass strand is rewound while applying a certain twist to form a glass yarn. As the sizing agent, a plastic sizing agent may be used in addition to the starch sizing agent. The glass yarn for warp and weft thus obtained is woven by a loom. 25 mm of weft and warp
The ratio of the number of hits per hit is 0.65 to 0.80, and weaving is performed so that the weave design is a plain weave. The glass woven fabric thus obtained is subjected to a heat deoiling to remove the sizing agent and then surface-treated with a silane coupling agent to obtain the glass woven fabric for a printed wiring board of the present invention. At this time, the glass woven fabric has a thickness of about 25 to 200 μm and a mass of 30 to 240 g / m.
It is in the range of ² .

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.

[0009]

The most commonly used glass woven fabric for printed wiring boards is the 7628 type glass woven fabric. This glass woven fabric is ECG for both warp and weft.
Using 75 1/0 glass thread, the number of warp threads per 25 mm is 42 to 44, the number of weft threads is 32 to 34, the thickness is 180 μm, and the mass is 205 to 2
It is 10 g / m ² . This glass woven fabric is widely used for general-purpose printed wiring boards because it has a well-balanced number of warp threads, weft threads, thickness, mass, etc.
It is also used for the surface layer of EM-3 type composite plates. However, as the automation of component mounting progresses, the warp and twist of the board have become a problem.

The present inventor realized that this problem might be due to the difference in the coefficient of thermal expansion between the warp direction and the weft direction of the substrate, and as a result of examination, the glass woven fabric of the present invention was obtained. It was found that when the weft yarn of the glass woven fabric is S glass fiber having a smaller coefficient of thermal expansion than E glass fiber, the thermal expansion coefficients of the warp direction and the weft direction of the substrate become similar and smaller. The warp of such a substrate was obviously smaller than that of a substrate using a 7628 type glass woven fabric. This is because by using S glass fiber as the weft of the glass woven cloth, even if it is subjected to a heat treatment in a later step, the warp of the substrate can be suppressed because the warp and the weft of the substrate have substantially the same thermal expansion coefficient. it can.

Since the 7628 type glass woven cloth has a difference in the number of warps and wefts, the substrate using this glass woven cloth has a difference in the coefficient of thermal expansion of the warps and the wefts, which is caused by a heat treatment in a later step. It is presumed that there is a difference in thermal expansion, which is a major cause of warpage and twist of the substrate. Generally, a glass woven fabric for a printed wiring board is designed so that the number of wefts is less than the number of wefts. The reason for this is not clear, but it is considered that the result is a balance between the productivity during the production of the woven fabric and the properties of the woven fabric. The glass woven fabric of the present invention can have the same warp and weft counts and the same number as that of the 7628 type, so that it can be made equivalent in productivity to the 7628 type, and when manufacturing a substrate. Can be easily replaced.

[0012]

【Example】

<Example 1> As a glass woven fabric, ECG75 1 was used as a warp.
/ 0 44 threads / 25mm, weft TCG75 1/0
[S glass fiber; Nitto Boseki Co., Ltd.] 32 pieces / 25 mm
Then, a plain weave glass woven fabric was woven. After deoiling by heating, treatment was carried out with a 0.7 wt% solution of a silane coupling agent, SZ-6032 [Toray Dow Corning Silicone Co., Ltd.]. Next, 100 parts by weight of unsaturated polyester resin, 40 parts by weight of styrene monomer, and 1 part by weight of cumene hydroperoxide were mixed to prepare a varnish. Glass woven cloth 2
Four pieces of glass paper [EPM-4050; Nippon Vilene Co., Ltd.] were sandwiched between the sheets to impregnate the varnish.
Further, it was sandwiched between two copper foils having a thickness of 35 μm and defoamed for 2 minutes, and then heated at 150 ° C. for 1 hour to obtain a 1.6 mm laminated plate.

<Embodiment 2> As a glass woven fabric, E was used as a warp.
42 / 25mm CG75 1/0, TCE7 for weft
A 5/0 32/25 mm plain weave glass woven fabric was woven. A laminated board was formed in the same manner as in Example 1 below.

<Comparative example> As a glass woven fabric, EC is used as a warp.
G75 1/0 44 threads / 25mm, weft thread ECG75
A plain weave glass woven fabric was woven with 1/0 at 32 pieces / 25 mm. A laminated board was formed in the same manner as in Example 1 below.

Regarding the laminated plates of Examples 1 and 2 and Comparative Example,
The warpage and the coefficient of thermal expansion of the laminated plate in the warp direction and the weft direction were measured and are shown in Table 1. The warpage is measured by cutting the laminated plate into a length of 400 mm x width of 340 mm, etching the copper foil, and drying at 130 ° C for 30 minutes, and measuring the maximum lift amount in the four corners of the laminated plate before and after etching as the amount of warpage. went. The thermal expansion coefficient is measured from 60 ° C to 1
It was determined from the slope of the coefficient of thermal expansion at 30 ° C. and measured using TMA / SS120C manufactured by Seiko Instruments Inc.

[0016]

[Table 1]

[0017]

The printed wiring board using the glass woven fabric of the present invention as a reinforcing material has a thermal expansion coefficient in the warp direction and that in the weft direction which are close to each other, and is smaller than that of the conventional board. Therefore, it is possible to obtain a substrate with a small dimensional change, and by setting the thermal expansion coefficients in the warp direction and the weft direction to be substantially close to each other, it is possible to obtain a printed wiring board with less warpage. Further, the substrate of the present invention is
Since the thermal expansion coefficients in the warp and weft directions are substantially the same, it is not necessary to consider the directionality of the substrate when designing the circuit or dividing the substrate, and a substrate having a greater degree of freedom can be obtained. Further, the glass woven fabric of the present invention can be made to have the same number of weft threads as the 7628 type, so that the characteristics can be improved without lowering the weaving efficiency.

Claims (3)

[Claims] 1. A warp is an E glass fiber yarn, a weft is an S glass fiber yarn, the weft and the warp have the same nominal count, and the ratio of the number of hammered threads per 25 mm of the weft and the warp is 0.65 to 0.
A glass woven fabric for printed wiring boards, which has a weave design of 80 and a plain weave. 2. The glass woven fabric according to claim 1, wherein the warp is ECG75 1/0 and the weft has a nominal count of 6
A glass woven fabric for a printed wiring board, which is an S glass fiber yarn having 7.5 tex. 3. A printed wiring board using the glass woven fabric according to claim 1 as a reinforcing material.