JP2612129B2 - Laminated board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate having excellent dimensional stability, warpage and workability.

[0002]

2. Description of the Related Art At present, as a laminated board for a printed circuit, a laminated board obtained by impregnating an epoxy resin with a glass nonwoven fabric as an intermediate layer base material, a glass woven fabric as a surface layer base material, and impregnating the base material with heat and pressure (hereinafter, referred to as a laminate). Composite laminates) are used in large quantities. Laminates made of glass woven fabric only and impregnated with epoxy resin have excellent mechanical strength, dimensional stability, heat resistance, etc., and high reliability of through-hole plating. Is widely used in industrial electronic devices. However, the glass woven substrate laminate is actually drilled because punching is not possible in the hole making step, which is one of the printed circuit board processing steps. Further, even after the V-cut processing, the glass woven fabric base material is used, so that the foldability is poor because the glass woven fabric base material is used, and the fibers of the glass woven fabric become whiskers on the V-cut surface.

On the other hand, a composite laminate is economically less expensive than a laminate made of a glass woven base material, is capable of punching holes, has an excellent V-cut property, and has excellent workability. Although attracting attention, it was evaluated that the reliability, dimensional stability, and warpage of the through-hole plating were lower than those of the glass woven fabric base laminate. The reason is that the weight ratio of the epoxy resin, which is an organic substance, to the glass woven cloth, which is an inorganic substance, is about 40: 6.
0. In this case, it is considered that the epoxy resin mainly has excellent various electric properties, and the glass woven fabric has good mechanical performance such as bending strength and dimensional stability. Since a general composite laminate uses a glass non-woven fabric as a base material for the intermediate layer, distortion tends to occur during heating and pressing compared to a laminate using a woven base material, so that dimensional stability,
It is believed that the warpage is inferior.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a laminate having excellent dimensional stability and warpage when processing a laminate without losing the excellent punching workability and V-cut workability of the conventional composite laminate. To provide.

[0005]

According to the present invention, the surface layer is made of a woven glass cloth impregnated with a thermosetting resin, and the intermediate layer contains 10 to 200% by weight of a filler with respect to the thermosetting resin. In a laminate made of a glass nonwoven fabric impregnated with a resin, the ratio of the thickness of the glass nonwoven fabric layer forming the surface layer to the thickness of the glass nonwoven fabric layer forming the intermediate layer is 1.0 or more and 3.0.
It is a laminate characterized by being 0 or less.

As shown in FIG. 1, a conventional composite laminate uses a glass nonwoven fabric as a base material of an intermediate layer, and a glass woven fabric having a thickness of 0.2 mm on each side of a surface layer. Therefore, there is a problem that the dimensional stability and warpage in the laminate processing step are inferior to those of the laminate of the glass woven fabric base material. The present invention was made as a result of various studies to solve this problem, and the basic structure of the composite laminate according to the present invention is that the surface layer is the same as the glass woven fabric and the intermediate layer is the same as the glass nonwoven fabric. The ratio of the thickness of the glass woven fabric layer forming the layer to the thickness of the glass nonwoven fabric layer forming the intermediate layer is 1.0.
It is more than 3.0 or less. In the case of a composite laminate, the thickness ratio varies depending on the thickness of the composite laminate, but conventionally, the thickness ratio is 0.1.
25 (1.6 mm in thickness) to 0.7 (1.0 mm in thickness), whereas 1.6 mm in thickness has a glass woven fabric layer forming a surface layer versus an intermediate layer. The ratio of the thickness of the glass nonwoven fabric layer is preferably 1.0 or more and 2.0 or less.

The glass woven fabric forming the surface layer has a thickness of 0.05 to 0.3 mm, preferably 0.1 to 0.2 mm.
It is. Further, the number of woven fabrics used for the surface layer is not limited to one, and any number of woven fabrics may be used as long as the configuration allows.
For example, FIG. 2 shows a case where two glass woven fabrics are used. The glass woven fabric is not particularly limited with respect to the monofilament diameter, the number of bundles, the number of punches, and the twist direction.
The glass nonwoven fabric forming the intermediate layer weighs 50 to 150 g per sheet, and the number of sheets is not particularly limited. However, in terms of punching workability and V-cut property,
Usually, the thickness of the intermediate layer is required to be 0.2 mm or more. The thermosetting resin used in the present invention includes a polyimide resin, a phenol resin, and a polyester resin in addition to the epoxy resin, and is not particularly limited. The filler used in the intermediate layer is aluminum hydroxide, silica, or the like, but is not particularly limited.

[0008]

【Example】

(Example 1) The composition of the epoxy resin varnish is as shown in Table 1.

[0009]

[Table 1]

The above materials were mixed to produce a uniform varnish. Next, for the surface layer, the varnish was impregnated and dried in a glass woven fabric (manufactured by Nitto Boseki) having a thickness of 0.2 mm so that the resin content was 42 to 45% to obtain a glass woven fabric prepreg.
Subsequently, a resin content of 1 was added to the varnish similarly blended for the intermediate layer.
25 parts of silica (Crystalite VX-3 manufactured by Tatsumori) as an inorganic filler and aluminum hydroxide (Al
70 parts of ₂ O ₃ · 3H ₂ O), ultra fine powder silica (manufactured by Shionogi Pharmaceutical Co., Ltd.)
Carplex) was added and mixed with stirring to produce an inorganic filler-containing varnish. This varnish containing an inorganic filler was impregnated and dried on a glass nonwoven fabric substrate (manufactured by Nippon Vileen Co., Ltd.) so that the content of the resin and the inorganic filler was 90% or more to obtain a prepreg. Two glass non-woven prepregs are used as an intermediate layer, and the glass woven prepregs are used for upper and lower surface layers, respectively.
Then, a copper foil was overlaid thereon, and heated and pressed to obtain a copper-clad laminate having a thickness of 1.6 mm. (Example 2) A copper-clad laminate having a thickness of 1.2 mm was obtained in the same manner as in Example 1 except that one glass nonwoven fabric prepreg as an intermediate layer was used. (Comparative Example 1) Glass woven prepregs of upper and lower surface layers were each 1
A glass-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Example 1 using three glass nonwoven prepregs as the intermediate layer. (Comparative Example 2) Glass woven prepregs of upper and lower surface layers were each 1
A glass-clad laminate having a thickness of 1.2 mm was obtained in the same manner as in Example 1 below, using two glass nonwoven prepregs of the intermediate layer. With respect to the obtained copper-clad laminate, a dimensional change rate, a warp, and a V-cut property in a processing step of a circuit board were measured. Table 2 shows the results.

[0011]

[Table 2] (Measurement method) Dimensional change rate: Measured in accordance with JIS C 6481 Warpage: Same as above V-cut property: A test piece having a width of 25 mm was prepared, and the glass nonwoven fabric layers on both surfaces were V-cut and the middle layer portion was cut off at 0. 5
mm. The bending strength was measured with a span of 50 mm, which was taken as the breaking strength.

[0012]

The laminate according to the present invention has greatly reduced dimensional shrinkage and warpage as compared with a conventional composite laminate, and is at the same level as a glass woven substrate laminate, and is used as an industrial printed circuit laminate. It becomes suitable.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a conventional composite laminate.

FIG. 2 is a schematic sectional view showing an example of a composite laminate of the present invention.

[Explanation of symbols]

 1 Copper foil 2 Glass woven prepreg 3 Glass nonwoven prepreg

Claims (1)

(57) [Claims] The surface layer is made of a glass woven fabric impregnated with a thermosetting resin, and the intermediate layer is made of a glass nonwoven fabric impregnated with a resin containing 10 to 200% by weight of a filler with respect to the thermosetting resin. A laminated plate, wherein the ratio of the thickness of the glass woven fabric layer forming the surface layer to the thickness of the glass nonwoven fabric layer forming the intermediate layer is 1.0 or more and 3.0 or less.