JPS60214585A - Metal base printed circuit 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 [Technical Field] The invention relates to a metal-based printed wiring board, particularly a metal-based printed wiring board that can improve the connection between the base metal and the conductive layer in the through-hole in a multilayer wiring board. This invention relates to wiring boards.

[Background Art] When forming a plurality of through holes in a multilayer metal-based printed wiring board, conventionally, as shown in FIG. , the front and back surfaces of the metal plate 1 and the hole wall surfaces of the through holes 9 are coated with insulating (ζ) resin 10, and then a conductive layer 8 is formed in the through holes 9 by plating.
A circuit layer 11 is formed on the front and back surfaces of the circuit layer 11 on the front and back surfaces.
were electrically connected by a conductive layer 8. However, in this manufacturing method, since it is not possible to maintain an insulating distance between the conductive layer 8 formed in the through hole 9 and the base metal 1, the absolute M reliability is low, especially at a part of the through hole corner, and the stability is low. It was difficult to mass produce it. Therefore, the present applicant submitted a metal-based printed wiring board having a structure as shown in FIG. 5 in Japanese Patent Application No. 59-464. This metal base printed wiring board is manufactured by drilling a large hole in a metal plate 1 serving as a base as shown in FIG. 4, filling the hole 2 with insulating resin 10, and then
A metal foil 5 is laminated and integrated on the front and back surfaces of the board through an insulating layer 4 formed of prepreg or the like, and then a plurality of through holes 9 are formed on the front and back sides of the laminate 6 so as to pass through the insulating resin 10. A conductive layer is formed on the inner surface of each through hole 9, and the metal foils 5 on the front and back surfaces are electrically connected by the conductive layer. However, in this method, a resin diluted with a solvent is used as the insulating resin 10, and when the prepreg is heated and pressure molded, the insulating layer til
Since t10 is also cured at the same time, it is difficult for volatile matter to escape during curing, resulting in the disadvantage that air bubbles remain inside, and the insulation resistance is as low as 106 to 107 Ω.

[Object of the invention 1 The present invention has been made in view of the points mentioned in -I-,
Metal-based printed wiring that improves the insulation reliability between the base metal and the conductive layer, and J- that the solvent component does not volatilize, leaving no air bubbles or lowering the insulation resistance. Its main purpose is to provide a substrate.

[Disclosure 1 of the Invention That is, the metal-based printed wiring board of the present invention has the following features:
Then, a hole is drilled in the metal plate 1, and a cured resin with excellent electrical insulation properties is inserted into the hole 2 through t4/l. ri 5, +(!j
L, a plurality of through holes 7 opening 11 on the front and back sides are formed in this laminate 6 at a position 1d passing through the cured resin material 3, and r
It is characterized by forming a conductive layer 8 in a through hole 7, and by using a cured resin material 3 and forming a through hole 7 in this cured resin material 3, the above object is achieved. This has been achieved.

The present invention will be explained in detail below. The base metal plate 1 includes copper plate, iron plate, aluminum plate, stainless steel plate,
Nickel plates, brass plates, etc. can be used. f
As shown in Fig. t51, large holes are made in these metal plates 1, and the fat compound 3 is press-fitted into the holes 2. It is a plate-shaped material formed by curing 4-1 fat and 15 epoxy O (fat, unsaturated polyester resin, polyimide, etc.), but it has high heat resistance f1. and has little loss on heating. For example, epoxy (-1 fat, polyimide is preferable. Also,
As shown in the figure, it is better to taper the end surface of the metal plate 3 (Jll fat compound 3) to make it easier to insert the metal plate 1 into the hole 2. In this state, the insulating layer 4 is laminated, and the metal foil 5 is laminated on the upper surface of the insulating layer 4, and the metal foil 5 is integrally molded.Here, the insulating layer 4 is called prepreg, which is formed by impregnating a base material with resin and drying it. (A base material impregnated with -1 fat can be used. In this case, glass cloth, synthetic fiber cloth, paper, non-woven fabric, etc. are used as the base material, and glass cloth is particularly preferred, and as the resin, epoxy resin, phenol resin, unsaturated polyester resin, diallyl phthalate resin, polyimide,
Heptafluoride resins and the like can be used, and epoxy resins are particularly preferred. Also, as the metal foil 5 lj:&)L brass,
Aluminum, stainless steel, nickel, etc. can be used, and usually they are used as they are, but if even higher adhesive strength is required, an adhesive layer may be provided on the side facing the insulating layer 4.

Next, 1: Laminate plate 6 is inserted so as to penetrate through cured resin material 3.
A through hole 7 is bored in the through hole 7, and a conductive hole 8 is formed in the through hole 7 by plating, so that the metal foils 5 on the front and back surfaces are electrically connected by the conductive layer 8. Thereafter, a wiring pattern is formed on the metal foil 5 according to a conventional method.

Therefore, by providing the through hole 7 not in the metal plate 1 part of the base but in the O (fatty compound 3 part), a sufficient insulation distance between the conductive layer 8 formed in the through hole 7 and the metal plate 1 can be maintained. Even if a plurality of through holes 7 are provided, the insulation f reliability is improved.Furthermore, the cured resin material 3 is placed in the hole 2 formed in the metal plate 1 of the base. By press-fitting and having yc, the volatile components of many companies will not volatilize from the 444 resin cured product 3 in the heat molding 11 and v as in the past, and air bubbles will not accumulate inside the substrate. In addition, there is no possibility that dents will occur in those areas, which will hinder circuit formation or spoil the appearance of the wiring board.Furthermore, as shown in FIG. 1(a), the cured resin material 3 By attaching a taper to the peripheral end of the hole, the cured resin material 3 can be easily inserted.The through hole 7 may be used in the through holes 9 and 1 shown in the conventional example. However, as shown in Fig. 12, it may be used as the connector connection terminal part 13 or as a men's lead wire part.

Next, the present invention will be explained based on examples.

Example: A hole with a diameter of 3 mm is drilled in an aluminum plate with a thickness of 116 m, and a cured epoxy resin is filled into the hole without any gaps.Next, a 0.0 mm thick hole is formed on both the front and back of this aluminum plate.
1mm epoxy resin impregnated glass cloth and thickness 0.0:1
Copper foils of 5+n... were laminated in this order toward the outside, and the second layer was laminated and molded at 50 Kg/cn+2 at 170° C. for 60 minutes to obtain a laminate. Next, through-holes were drilled in this laminate at positions that passed through the cured resin, a conductive layer was formed in the through-holes, and the copper foils on the front and back were electrically connected with conductive I- to obtain an aluminum-based printed wiring board. Ta.

Temporary Example - An aluminum-based printed wiring board was obtained in the same manner as in the example except that the holes of the aluminum plate described in 1- were filled with an epoxy resin liquid having a resin content of 90%.

Next, the results of the appearance smoothness, the number of circuits in the through-hole portion, and the insulation resistance of the through-hole portion of the wiring board obtained in Example L and the comparative example and the conventional wiring board are shown.

As described above, the present invention involves laminating metal foil on the surface of a metal plate via an insulating layer, and forming a plurality of through holes in the laminated plate at positions passing through the cured resin. Since the conductive layer is formed on the base metal, even if 11 through holes such as multiple through holes are formed in the cured resin, the distance between the conductive layer and the base metal will be maintained by ensuring a sufficient insulation distance between the conductive layer and the base metal. This can improve insulation reliability, and since the cured resin is loaded into the holes in the metal plate, the solvent in the resin does not volatilize during molding, unlike conventional solvent-diluted resin. This can be avoided by preventing air bubbles from remaining and increasing the insulation resistance.

[Brief explanation of drawings]

1(,) to (e) are cross-sectional views of one embodiment of the present invention, 2
The figures are explanatory diagrams of other embodiments same as above, and Fig. 3(a)(b)(
c) is a sectional view of a conventional example, FIGS. 4(a) and 4(b) are a plan view and a sectional view of another conventional example, and FIG. 5 (aOb) is a plan view and a sectional view of the same. 1 is a metal plate, 2 is a hole, 3 is a cured resin, 4 is an insulating layer,
5 is a metal foil, 6 is a laminate, 7 is a through hole, and 8 is a conductive layer. Agent Patent Attorney Ishi 1) Chief 78- Figure 1 (b) (C) Figure 2 Cause 3 (0) (e)

Claims (1)

[Claims] (1) Drill a hole in the metal plate, load a cured resin with excellent electrical insulation into the hole, laminate metal foil on the surface of the metal plate via an insulating layer, and pass through the cured resin. A metal-based printed wiring board characterized in that a plurality of through holes opening to the front and back sides are formed in the laminate at certain positions, and a conductive layer is formed in the through holes.