JPS6147245A - Manufacture of metallic-base laminated plate - 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 present invention relates to a method for manufacturing a metal-based laminate used as a printed wiring board.

[Background Art 1] Recently, MtWi substrates for printed wiring boards used in electrical and electronic appliances, etc., are based on metal plates such as steel plates. This -*
The S-base laminate has excellent properties such as heat dissipation and magnetic shielding due to the base metal substrate.
It also has the advantage that the base metal substrate can be used as an mB case, allowing the device to be made smaller. However, in such a laminated board for a printed wiring board based on an IR substrate, since the metal substrate is a good conductor of electricity, a special method is taken to form the through holes. That is, as shown in FIG. 1(,), a through hole 2 is provided in a metal substrate 1, and a thermosetting resin 3 is filled into the through hole 2 and hardened as shown in FIG. Later, a metal foil 4 such as 114M is pasted on the metal substrate 1 using an insulating adhesive resin M6 as shown in FIG. 5 and through-hole plating at the through-hole.
So do it. In this way, since the through hole 5 is formed by the resin 3 portion, electrical insulation between the through hole 5 and the metal substrate 1 can be reliably obtained. However, the problem here is that when the resin 3 is filled into the through hole 2 of the metal substrate 1 and cured, air bubbles in the resin remain as they are, and when the resin is heated and cured, volatile matter remains as air bubbles.

As a result, air bubbles 7 are included in the resin 3 as shown in FIG. 2(a). If the air bubbles 7 exist in the resin 3 in this way, the air bubbles 7 will expand due to heating during lamination, etching, or soldering of the gold 14 M4, and the metal M4 will be expanded as shown in FIG. 2(c). If a bulge occurs in the through hole 5 or a bubble 7 appears in the through hole 5 as shown in Fig. 2(b).
This results in communication with the metal substrate 1, and when through-hole plating is applied to the through-holes 5, a problem arises in that the through-hole plating circuit becomes conductive with the metal substrate 1 and is shunted. .

[Object of the Invention J The present invention has been made in view of the above points, and provides a metal-based laminate that can prevent air bubbles from being included in the resin filling the through-holes of the metal substrate. The purpose is to provide a manufacturing method.

[Disclosure of the Invention] The method for producing a 4-base laminate according to the present invention is as follows:
A metal base is laminated by providing a through hole 2 in a metal substrate 1, filling the resin 3 into the through hole 2 and hardening it, pasting a metal foil 4 on the metal substrate 1, and then drilling a through hole 5 in the through hole 2. In manufacturing the plate, the resin 3 filled in the through hole 2 is heated and hardened under reduced pressure.The above object is achieved by heating and hardening the resin 3 under reduced pressure. Hereinafter, the present invention will be explained in detail by way of examples.

As the metal substrate 1, an iron plate such as a steel plate or a stainless steel plate,
An aluminum plate, a brass plate, a copper plate, a nickel plate, etc. can be used, and through holes 2 are bored in the portions where through holes 5 are required, as shown in FIG. Then, inside this through hole 2, thermosetting tMI such as epoxy resin or imide resin is applied! W3 is filled as shown in FIG. 1(b) and cured by heating. At this time, in the present invention, heat curing is performed under reduced pressure. In other words, thermosetting resin JIIt3 once melts to a low viscosity by heating, and then hardens by delatching.If the resin m3 is heated and hardened under reduced pressure in this way, when the resin 3 melts to a low viscosity, The air bubbles originally contained in the resin 3 and the air bubbles due to the volatile content of the resin 3 are deflated, and the resin 3 can be filled into the through hole 2 and hardened in a state in which no air bubbles are included. The degree of depressurization varies depending on the type of resin 3, melt viscosity, etc., but it is generally preferred to be 600-Ugly H or less.The through hole 2 of the metal substrate 1 is filled with the resin 3 in this way and cured. Thereafter, as shown in FIG. 1(c), the metal 14 is laminated and bonded to the surface of the metal substrate 1 via the electrically insulating adhesive tM fat layer 6 by hot pressing. Adhesive resin layer 6
Usually, a resin-impregnated base material is used.

Resin-impregnated base materials include epoxy resin, phenol resin, unsaturated polyester resin, diallyl 7-thale resin, polyimide resin, etc.
It is obtained as a prepreg by impregnating and drying a thermosetting resin such as a 7-fluoride resin, and among them, a prepreg prepared by impregnating a lath cloth with an epoxy resin is preferable. The metal N4 is laminated and bonded to the gold AfI plate 1 by heating and press-molding the metal N4 between the two. The metal N4 can be made of copper, brass, aluminum, stainless steel, nickel, etc., but if particularly high adhesion is required, #! on the back side of the gold aTi4. It is better to apply adhesive in advance.
14M4 is laminated, the metal foil 4 is etched to form a circuit pattern, and a through hole 5 is drilled in the resin 3 portion of the through hole 2 as shown in FIG. 1(d). Finish with through-hole plating.

Next, filling and hardening the resin 3 into the through hole 2 of the metal substrate 1 will be explained using a specific example.

Fill the through hole of Nagara Ran L am with epoxy resin to 500mmHH
The epoxy resin was cured by heating at 100° C. for 20 minutes under reduced pressure. In this thing, through hole 10
Of the 0 pieces, 0 pieces had bubbles.

A-ruled 1'' - Imide@f resin was filled into the through holes of the steel plate, and the imide resin was cured by heating at 130° C. for 20 minutes under reduced pressure of 30018H. In this thing, the through hole 100
Of these, 0 had air bubbles.

-81 Fill the through hole of the steel plate with epoxy resin and heat it under normal pressure (760
The epoxy resin was cured by heating at 100°C for 20 minutes. In this item, through hole 1
Out of 00 samples, 75 bubbles were present.

By heating and curing the resin under reduced pressure in this way,
It is confirmed that it is possible to prevent air bubbles from remaining in the If fat.

[Effects of the Invention] As described above, in the present invention, the resin filled in the through hole of the metal substrate is heated and cured under reduced pressure.
It is possible to prevent air bubbles from remaining in the resin due to defoaming by reducing the pressure, and there is no risk that the expansion of the air bubbles will cause bulges in the gold melon foil or that the air bubbles will damage the insulation properties of the through holes. It is something.

[Brief explanation of the drawing]

Figures 1 (a), (b), (c), and (d) are cross-sectional views showing each step in the production of metal-based laminates, Figure 2 (-), (b), and (c).
is a partially enlarged sectional view showing a problem in the conventional example. 1 is a metal substrate, 2 is a through hole, 3 is a resin, 4 is a metal tube, 5
is a through hole.

Claims (1)

[Claims] (1) Manufacture a metal base laminate by creating a through hole in a metal substrate, filling the through hole with resin and curing it, pasting metal foil on the metal substrate, and drilling a through hole in the through hole. A method for manufacturing a metal-based laminate, characterized in that the resin filled in the through holes is heated and cured under reduced pressure.