JPH08174761A - Copper-clad laminate and prepreg - Google Patents

Abstract

PURPOSE: To reduce a coefficient of linear expansion in one direction only of a printed wiring board without deteriorating electrical and other various properties by using glass fiber cloths wherein a ratio (warp/weft) of the density of warps to wefts of the glass fiber cloths is within a specific range. CONSTITUTION: A weaving method of a glass fiber cloth may be the same as that for producing an ordinary woven fabric, and examples thereof include Turkish satin weave. Also, a ratio of the density of warps to wefts is at least 1.5 and at most 2.5. In the case where the ratio is 1.5 or below, the effect of reducing a coefficient of linear thermal expansion in a lengthwise direction is insufficient, and, in the case of 2.5 or more, the effect of improving a coefficient of linear thermal expansion does not become more remarkable than that. Therefore, when the glass fiber cloths are formed into a laminate, warpage and the like of the laminate are apt to be caused. It is preferable for a low coefficient of linear thermal expansion that the density of the warps and wefts is at least 45 threads/25mm for the warps and at least 28 threads/25mm for the wefts. Further, a ratio of the preferable density is at least 1.7 and at most 2.2, and the density (threads/25mm) of the warps/wefts is, for example, 74/36, 52/30, 57/30, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board produced by a combination of a glass fiber base material thermosetting resin laminate and a prepreg by reducing the linear expansion coefficient in the longitudinal direction, or both sides or one side. When the printed wiring board is used by connecting it to a component such as mounted ICs or a substrate with a small linear expansion coefficient, such as a liquid crystal control board, by reducing the linear expansion coefficient in the vertical direction. It improves reliability.

[0002]

2. Description of the Related Art Glass fiber-based copper clad laminates and prepregs have a linear expansion coefficient of about 15 ppm / ° C. in the longitudinal and transverse directions, and are used in connection with a material having a small linear expansion coefficient such as a liquid crystal panel. In this case, the connection reliability was insufficient and practical application was difficult. Therefore, conventionally, a printed wiring board using an S glass cloth or a D glass cloth is used instead of the E glass cloth which is usually used to reduce the linear expansion coefficient and maintain the connection reliability. However, these are disadvantageous in that they are expensive and have poor drilling workability during the production of printed wiring boards. Was desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the linear expansion coefficient of a printed wiring board in only one direction without deteriorating electrical characteristics and other characteristics. To provide a laminated laminate and a prepreg.

[0004]

The present invention relates to a ratio of warp yarn density (threads / 25 mm) to weft density (threads / 25 mm) in a glass cloth used for a glass fiber-based copper clad laminate and a prepreg. A glass cloth having a warp / weft of 1.5 or more and 2.5 or less is used, and the glass cloth used is preferably E-glass. Thermosetting resin copper clad laminate and thermosetting The present invention relates to a resin-impregnated prepreg.

The method for weaving the glass cloth used in the present invention is not particularly limited, and any method can be used as long as it is a method normally used for producing a woven cloth, such as Turkish satin weave. The warp / weft density ratio is 1.5 or more and 2.5.
It is the following. When it is 1.5 or less, the effect of reducing the linear expansion coefficient in the longitudinal direction is small, and when it is 2.5 or more, the effect of improving the linear expansion coefficient does not increase any more, and warpage or the like is likely to occur when the laminate is used. The warp and weft density is 45 warp threads / 2
5 mm or more and 28 wefts / 25 mm or more are preferable for achieving a low linear expansion coefficient. The preferable density ratio is 1.7 or more and 2.2 or less, and the density of warp yarn / weft yarn (book / 25 m
As m), for example, 74/36, 52/30, 57
/ 30 etc. The resin content is preferably 30% by weight or more and 45% by weight or less in order to reduce the linear expansion coefficient and to keep the properties of the laminated plate good. To further reduce the linear expansion coefficient in the longitudinal direction, the warp yarn is It is preferable that the number of bundled monofilaments is large, and that the diameter of the warp monofilament is large. Since the thickness of the thread is limited, and the number of bundles of monofilaments and the diameter have a contradictory relationship, for example, when the diameter of monofilaments is 5 to 9 μm, the number of bundles of about 150 to 400 is preferable.

[0006]

EXAMPLES Examples of the present invention will be described below.

(Example 1) Density of warp yarn / weft yarn (book / 25
(mm) ratio is 74/36 (2.05), the glass cloth which consists of E glass is used, and the content of epoxy resin is 4
A prepreg of 0% by weight was produced. Eight prepregs were stacked and heat-pressed to prepare a copper-clad laminate. Table 1 shows the evaluation results as a printed wiring board.

(Example 2) A warp / weft density ratio of 52
Using E glass cloth of / 30 (1.96), a prepreg having an epoxy resin content of 40% by weight was prepared. Eight prepregs were stacked and heat-pressed to prepare a copper-clad laminate. Table 1 shows the evaluation results as a printed wiring board.

(Comparative Example 1) The warp / weft density ratio is 59.
Using E glass cloth of / 58 (1.02), a prepreg having an epoxy resin content of 40% by weight was prepared. Eight prepregs were stacked and heat-pressed to prepare a copper-clad laminate. Table 1 shows the evaluation results as a printed wiring board.

(Comparative Example 2) The warp / weft density ratio was 59.
Using S glass cloth of / 58 (1.02), a prepreg having an epoxy resin content of 40% by weight was produced. Eight prepregs were stacked and heat-pressed to prepare a copper-clad laminate. Table 1 shows the evaluation results as a printed wiring board.

[0011]

[Table 1]

The cost of the copper clad laminate obtained in Example 1 is 1.5 times that of the ordinary FR-4 epoxy resin laminate, and that of Example 2 is 1.6 times. 1 is 1.
The cost was 0 times and the cost was 5.0 times.

(Measurement Method) 1. Linear expansion coefficient: According to JIS C 6481 2. Connection reliability: MIL-STD-202F, 107D
By 3. Drill workability: rotation speed 60,000 rpm, feed rate 3
The wear rate (%) of the drill blade after 10,000 holes at m / min was determined.

[0014]

INDUSTRIAL APPLICABILITY The copper clad laminate or prepreg of the present invention has a connection reliability when it is used by connecting with a material having a small linear expansion coefficient such as a liquid crystal panel by reducing the linear expansion coefficient only in the vertical direction. The present invention provides a printed wiring board or a multilayer printed wiring board that maintains its properties and is inexpensive and excellent in workability.

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Claims (6)

[Claims] 1. Density of warp of glass cloth (book / 25 m
m) and weft density (thread / 25 mm) ratio (warp / weft)
A thermosetting resin copper-clad laminate characterized by using a glass cloth having a ratio of 1.5 to 2.5. 2. The thermosetting resin copper-clad laminate according to claim 1, wherein the glass cloth is made of E glass. 3. The thermosetting resin copper-clad laminate according to claim 1, wherein the resin content of the entire laminate is 30% by weight or more and 50% by weight or less. 4. Density of warp of glass cloth (book / 25 m
m) and weft density (thread / 25 mm) ratio (warp / weft)
A thermosetting resin-impregnated prepreg, characterized by using a glass cloth having a ratio of 1.5 to 2.5. 5. The thermosetting resin-impregnated prepreg according to claim 4, wherein the glass cloth is made of E glass. 6. The thermosetting resin-impregnated prepreg according to claim 4, wherein the resin content is 30% by weight or more and 50% by weight or less based on the whole laminated plate.