JPS61117883A - Multilayer printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [I*Technical Field] The present invention relates to a multilayer printed wiring board substrate with excellent drillability.

[Background technology J] Previously, in manufacturing substrates used for multilayer printed wiring boards, metal foils such as copper foil were laminated on both the front and back sides of prepreg, which was formed by impregnating lath woven cloth with epoxy resin and drying it. A laminate was created using the H1 laminate, and then metal foil was loaded and pressed onto both the front and back sides of the H1 laminate via prepreg having the same structure as above to create a substrate for a multilayer printed wiring board.

In this way, conventional boards use prepreg, which is made by impregnating lath woven cloth with resin and drying it, as the inner layer core material, which makes it difficult to drill holes for through-holes. There were problems in that the life of the drilling blade was short, and the inner wall surface of the through hole was rough, resulting in poor quality.

[Objective of the Invention J The present invention has been made in consideration of the above points, and provides a substrate for a multilayer printed wiring board that can extend the life of a drill blade and improve the quality of the substrate. The purpose is to provide the following.

Disclosure 1 of the Invention That is, the substrate for a multilayer printed wiring board of the present invention has JK? It is characterized by one layer of outer layer material 8 with metal foil 7 provided on both sides of a laminate plate 3 formed by laminating 12.2, and a nonwoven fabric is used as the base material of the inner layer core material 1. By using this, the above purpose was achieved.

The present invention will be explained in detail below. The nonwoven fabric used for the base material is a cloth, nonwoven fabric, or mat made of inorganic fibers such as glass and asbestos, or composites of polyamide, polyester, etc. and natural fibers such as fat fibers and paper, alone or in a blend, and synthetic Ia fibers. This also includes those bound with resin binding and those that utilize entangled fibers. Further, as the resin, epoxy resin, polyimide, etc. can be used, and these resins can be used alone or in combination with an inorganic filler.

A prepreg 6 is formed by impregnating and drying these resins into the nonwoven fabric base material, and #I is applied to both sides of the prepreg 6.
A metal such as M [2] is laminated to create an 81-layer plate 3. Next, after forming a circuit on the front and back surfaces of this laminated plate 3, outer layers are formed on both the front and back sides of the laminated plate 3, respectively, as shown in FIG. An outer layer material 8 to which a metal M7.7 such as copper foil is adhered is placed via a prepreg 4.4, and is molded under heat and pressure to obtain a substrate for a multilayer printed wiring board. As the outer layer prepreg 4, a prepreg based on the nonwoven fabric used above may be used, but a prepreg formed by impregnating a lath woven fabric with a resin and drying it is mainly used.

Therefore, by using non-woven fabric as the base material for the core material 1 in lamination [3], it is superior in drilling workability compared to a laminated board formed using only woven fabric as a base material, and therefore, the multilayer printed wiring board The lifespan of the drilling blade of the drill for the PC board is long (
Also, the roughness of the inner wall surface of the drill has improved (the unevenness of the inner wall surface is small), and the through-hole plating is reliably glossy.
Furthermore, there is no possibility of poor connections between the inner layers of the through-hole portions, and the quality of the board can be improved. Further, by using the prepreg 6 made of nonwoven fabric as a base material, it is possible to reduce the cost of the inner layer core material 1. Furthermore, since the inner core material 1 has good hole-drilling properties, punching can be performed instead of drilling, and productivity can be improved.

In the above embodiment, the prepreg 6 made of a non-woven fabric as the base material was used as the inner layer core material 1, but the prepreg 5 made of a woven fabric and the prepreg 6 made of a non-woven fabric may be used together. In other words, as the base material of the inner layer core material 1, a layered material of a plus non-woven fabric and a lath woven fabric (also called ``Funbobut'') may be used. In this case, as shown in Fig. 3(a) As shown in FIG. 3(b), the inner layer core material 1 may be formed by stacking prepregs 5.5 formed using woven fabric as a base material on both sides of prepreg 6 formed using nonwoven fabric as a base material. The inner layer core material 1 may be formed by stacking prepregs 6.6 formed using a non-woven fabric as a base material on both sides of a prepreg 5 formed using a woven fabric as a base material. Moreover, a prepreg having a nonwoven fabric as a base material may be used for any inner layer core material 1 of a multilayer printed wiring board substrate having three or more layers.

The present invention will be specifically described below based on examples.

1DI As an inner layer core material, a prepreg of 700 g/2 weights was obtained by impregnating and drying an epoxy resin face into a lath nonwoven fabric weighing 75 g/2 weights. 0.07 on both sides of this prepreg
Place 0m5 @ foil, sandwich it between the metal plates and apply pressure 4
A copper-clad laminate with a thickness of 0.5-1 was formed by layer molding at 0 Kg/c so 2 and a temperature of 170° C. to form a copper-clad laminate (2), and a circuit was formed on the surface of this laminate.

On the other hand, a 200 g/s'' lath woven fabric was impregnated with epoxy resin in a booth and dried to obtain a 400 g/s'' resin-impregnated prepreg, and two sheets of each prepreg were stacked on both sides of the copper-clad laminate. Furthermore, #! foil with a thickness of 0.035 mm was layered on the outside thereof, and laminated and molded under the same conditions as the above laminate to obtain a 4-layer printed rice arranging board substrate with a thickness of t'1.4++.

Next, the heat resistance of the multilayer printed wiring board substrate obtained above and the roughness of the inner wall of the through hole when the hole was drilled were examined. As a result, there were no abnormalities during soldering at 260°C for 20 seconds and 70 seconds, and the inner wall surface of the inner layer core material had a height of 11.
It was 10μ in 00hi and g.

1. Epoxy on glass cloth of 200g/key 2 as inner layer core material! 400g of 1llffi Wanimata impregnated and dried
/ m' U (grease-impregnated prepreg was obtained. 0.070 mm copper foil was placed on both sides of these two prepregs, and a metal plate N11ll was sandwiched between the upper blades 40 K g/c.
m', laminated for 100 minutes at a temperature of 170°C to a thickness of 0.
No. 51 copper-clad laminates were obtained. For the dog, layer two sheets of the same N4rIt prepreg as above on both sides of this copper-clad laminate, and
Furthermore, layer 0.035m-thick t14M on the outside,
Laminate molded under the same conditions as the above laminate to a thickness of 1.41mm.
1! A substrate for a printed IIL board was obtained.

Next, the heat resistance of the conventional multilayer printed M board substrate and the roughness of the inner wall of the through hole when the hole was drilled were examined.

As a result, there was no abnormality in heat resistance, and the roughness of the inner wall surface of the inner core material was 15μ at 10,000 hits.

[Effects of the Invention] As described above, the present invention forms a laminate by laminating gold 1!4N on both sides of an inner layer core material whose base material is a nonwoven fabric impregnated with a phase-resistant material. Since the outer layer material is laminated with metal foil, it is possible to improve drilling workability without compromising the heat resistance of the board, prolonging the life of the drill bit, and making it possible to drill inside through-holes. The roughness of the wall surface is good (this makes it possible to improve the quality of the multilayer printed product #iI board).

[Brief explanation of the drawing]

FIG. 1 is a schematic exploded sectional view of an embodiment of the present invention, FIG. 2 is a partially cutaway sectional view of the same laminated plate, and FIGS. 3(a) and 3(b) are explanatory views of the core material. 1 is an inner layer core material, 2 is a metal foil, 3 is a laminate, 7 is a metal foil, and 8 is an outer layer material.

Claims (1)

[Claims] (1) It is characterized by laminating an outer layer material provided with metal foil on both sides of a laminate plate formed by laminating metal foil on both sides of an inner layer core material whose base material is a nonwoven fabric impregnated with resin. A substrate for multilayer printed wiring boards.