JPH03108786A - Manufacture of copper-clad lamination board - Google Patents

Abstract

PURPOSE:To acquire a lamination board of a small dielectric constant and good punching processability which hardly causes thinning of a through-hole diameter by mixing polyethylene terephthalate fiber and glass fiber at a specified rate, by impregnating resin to form prepreg in a nonwoven fabric of a core layer and a woven fabric of a surface layer and by laminating a specified sheets of prepreg and a copper foil on one or both sides thereof. CONSTITUTION:Polyethylene terephthalate fiber and glass fiber are collected to form yarn (thread) as a base material of a surface layer, and woven fabric is manufactured. Varnish is impregnated into the base material to acquire prepreg. Then, polyethylene terephthalate fiber and glass fiber are mixed at a rate of 30 to 95wt.% against 70 to 5wt.% to manufacture nonwoven fabric. Varnish is impregnated into the base material to acquire prepreg. One sheet of surface layer prepreg is laminated on each of both sides of 6 sheets of core layer prepreg and a copper foil is further laminated. An epoxy resin copper-clad lamination board is obtained by heating and pressurizing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior to Industrial Use) The present invention relates to a low dielectric constant printed circuit board with excellent punching workability.

(Prior art) Conventionally, in order to lower the dielectric constant of printed circuit boards, a laminated layer was used in which a prepreg made of polyethylene terephthalate fiber nonwoven fabric was used as the core layer and a prepreg made of glass fiber cloth was used as the surface layer. The board is well known.

This laminate has problems in that, compared to a laminate made of a glass cloth base material, the wall surface is more likely to be chipped and fibers remain when punched, and the diameter of the through hole is more likely to become narrower after heat treatment.

In addition, in order to use a low dielectric constant laminate in a high frequency range, it is necessary to use a glass cloth base material with a high dielectric constant for the layer below the circuit in order to maintain the strength of the laminate. had its limits.

(Problems to be Solved by the Invention) Therefore, as a result of intensive studies to improve the above-mentioned drawbacks, the inventors of the present invention have found that by using a nonwoven fabric made of a mixture of polyethylene terephthalate fiber and glass fiber as the base material of the core layer. It has been found that it is possible to achieve both a low dielectric constant of the laminate and good punching workability.

(Means for Solving the Problems) The present invention provides polyethylene terephthalate fibers of 30 to 95
The core layer is a prepreg prepared by impregnating a non-woven fabric with resin and 70 to 5 weight percent of glass fiber, and the surface layer is a glass fiber woven fabric or a blended fabric of glass fiber and polyethylene terephthalate fiber. This is a distinctive method for manufacturing copper-clad laminates.

In the present invention, the base material used for the surface layer is a woven fabric in which glass fiber alone or yarn (thread) made of bundles of polyethylene terephthalate fiber and glass fiber is used as the warp and weft.

The feature of the present invention lies in the base material of the core layer. This base material is a nonwoven fabric made of a mixture of polyethylene terephthalate fiber and glass fiber.

Polyethylene terephthalate fiber has a thickness of 20 to 90μ
A thickness of 30 to 60μ is preferred.

Glass fibers with a thickness of 5 to 13 microns tend to become narrower in each hole, resulting in poor dimensional stability.

In the nonwoven fabric of the core layer and the woven fabric of the surface layer, the preferred blending ratio of side fibers is 30% polyethylene terephthalate fiber.
-60% by weight and 70-40% by weight of glass fiber.

The woven fabric thus obtained is impregnated with a resin to obtain a prepreg. The resin to be impregnated is not particularly limited, such as epoxy resin, phenol resin, unsaturated polyester resin, etc., but epoxy resin is preferable in order to fully exhibit the characteristics of this woven fabric.

Thereafter, according to a conventional method, a predetermined number of prepreg sheets and copper foil are superimposed on one or both surfaces thereof, and the prepregs are heated and press-molded to obtain a copper-clad laminate.

(Function) The feature of the present invention is that polyethylene terephthalate fiber and glass fiber are mixed in a specific ratio as a base material to give a peripheral group +1,
Polyethylene terephthalate non-fiber, 6-9μ
is preferred. The type of glass fiber is not particularly limited, but
E-glass is preferred.

These two types of fibers are produced by mixing and paper-making the ratio of 30 to 95 weight percent polyethylene terephthalate fiber and 70 to 5 weight percent glass fiber. If the proportion of polyethylene terephthalate fibers is less than 30% by weight, the dielectric constant will not be lowered very much, and if it is more than 95% by weight, the through-holes will tend to become narrower during a heat process or the like.

On the other hand, the base material used as the surface layer may be a glass fiber woven fabric, but a mixed woven fabric of polyethylene terephthalate fibers and glass fibers is preferable. In this case, these two types of fibers are usually 30 to 80% by weight of the former and 70 to 2% by weight of glass fiber.
It is bundled into yarn at a proportion of 0% by weight. A woven fabric is produced using this yarn as warp and weft threads. If the proportion of polyethylene terephthalate fibers is less than 30% by weight, the dielectric constant will not decrease so much, and furthermore, during punching,
The punching resistance is large, and cranks are likely to occur at yarn intersections. If the amount is more than 80% by weight, the strength of the core layer will be improved compared to a laminate with a core layer based on cloth that undergoes a heat process, etc., and it will be difficult to cut when only polyethylene terephthalate fiber is used during punching. Prevents fibers from remaining due to color. Furthermore, even if the polyethylene terephthalate fiber, which is a thermoplastic resin, softens during heating during the soldering process, the glass fiber maintains its strength, thereby preventing the polyethylene terephthalate fiber from shrinking and reducing the diameter of the through hole.

(Example) The present invention will be specifically explained using examples. In the formulation, "part j" and "%" indicate parts by weight and weight %.

(Preparation of festival) A festival with a resin content of 50% was produced using the following formulation.

Brominated bisphenol A type epoxy resin 100 parts (Evogishie equivalent: 480) Diaminodiphenylmethane 10 parts 2-ethyl-4-medylimidazole 0.15 parts Methyl ethyl ketone About 125 parts Example 1 Polyethylene terephthalate with a filament diameter of 30 μm was used as the base material for the surface layer. Fibers and 1 liter of glass (E glass) with a filament diameter of 9 μ are bundled in 50 parts to 501 W 1 combination to form yarn, number of vertical strokes: 42/25 mm, number of horizontal strokes: 32 wood/25 strokes, thickness. 0. Bi-woven fabric was manufactured. This base material was impregnated with the varnish to obtain a prepreg with a resin content of 40%.

Next, as a base material for the core layer, polyethylene terephthalate with a filament diameter of 30 μm and glass fiber (E glass) with a 9 μm diameter were mixed in a ratio of 50 parts by weight to 50 parts by weight to form a paper of 1.00 g/c+fl. A nonwoven fabric was produced. This base material was impregnated with the varnish to obtain a prepreg with a resin content of 68%.

8 prepregs for surface layer on both sides of 6 prepregs for core layer
One sheet was stacked on top of the other, and then a copper foil was stacked on top of the other, followed by heating and pressing to obtain an epoxy resin copper-clad laminate having a thickness of 1.6 mm.

Example 2 A polyethylene terrestrial fiber nonwoven fabric having a rectangle thickness of 0.2 mm was used, except that the sub-base of sugar and glass fibers was used as the opposing shaft portion of the material.

Hereinafter, as in Example 1, the varnish was used to obtain a thickness of 1.
A 6+um epoxy resin copper-clad laminate was obtained.

Comparative Example 2 As a base material, the glass fiber woven fabric used as the surface layer base material in Comparative Example 1 was used for all layers, and the varnish was used in the same manner as in Example 1 to form an epoxy resin copper with a thickness of 1.6 mm. A stretched laminate was obtained.

Comparative Example 3 The prepreg for the surface layer used in Example 1 was used.

Next, as a base material for the core layer, polyethylene terephthalate fibers with a filament diameter of 30 μm and glass fibers (E glass) with a filament diameter of 9 μm were mixed at a ratio of 98 parts by weight to 1 part of 2ffi to produce a nonwoven fabric of 100 g/cJ. .

The varnish was mixed with this base material to obtain a prepreg with a resin content of 68%.

Prepregs for the surface layer were placed on both sides of the six prepregs for the core layer by Q-filtering in the same manner as in Example 1 to obtain an epoxy resin copper-clad laminate having a thickness of 1.5 mI11.

Example 3 An epoxy resin copper-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Example 1.

Example 4 As the base material for the surface layer, glass fiber with a filament diameter of 7 μm was used, with the number of vertical strokes 42 pieces/25 mm and the number of horizontal strokes 58 pieces/25 m.
A glass fiber woven fabric of 40% was used, and this base material was impregnated with the varnish to obtain a prepreg with a resin content of 40%.

7 was used as prepreg for the core layer in Example 1.
A copper-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Example 1.

Comparative Example 1 The surface layer base material was glass fiber with a filament diameter of 9 μ, the number of vertical strokes was 42/25 mm, and the number of horizontal strokes was 32/25 mm.
A 25 mm glass fiber woven fabric was used, and as the core layer base material, one polyethylene tepreg with a filament diameter of 30ti was used.
Stack the sheets, then overlap the copper box, and heat and pressurize to a thickness of 1.
．． A 5 mm copper-clad laminate was obtained.

Comparative Example 4 The prepreg for the surface layer used in Example 1 was used.

Next, as the core layer base +1, polyethylene terephthalate fiber with a filament diameter of 30μ and a filament diameter of 9μ
A nonwoven fabric of 100 g/c+fl was manufactured by mixing and paper-making the glass fiber (E glass) in a ratio of 20 parts by weight to 80 parts by weight. This base material was impregnated with the varnish to obtain a prepreg having a resin content of 68%.

8 prepregs for surface layer on both sides of 6 prepregs for core layer
One sheet was stacked on top of the other, and then a copper foil was stacked on top of the other, and heated and pressed to obtain a copper-clad laminate having a thickness of 1.6 mm.

Regarding the copper-clad laminates obtained on each side, dielectric constant, punching workability, diameter of through holes after heat treatment, etc. were measured. The results obtained are shown in Table 1.

(Effects of the Invention) As is clear from the above effects, the copper-clad laminate of the present invention has a glass fiber woven fabric as the base layer +2, or a glass fiber woven fabric as the surface layer base material and a core layer base material. Compared to those using polyethylene terephthalate fiber nonwoven fabric as the material, the dielectric constant is the same or lower, the punching processability is excellent, and there is almost no thinning of the Surpore diameter.

Therefore, it is most suitable for circuit boards that require high frequency characteristics.

Claims (1)

[Claims] (1) The core layer is a prepreg prepared by impregnating a non-woven fabric made of 30-95% by weight of polyethylene terephthalate fibers and 70-5% by weight of glass fibers, and the surface layer is made of glass fiber woven fabric or glass fiber and polyethylene terephthalate. A method for manufacturing a copper-clad laminate, which comprises laminating a prepreg impregnated with a resin into a blended fabric with fibers, molding it on one side or placing copper foil on both sides, and heating and pressurizing the fabric.