JPH0316195A - Printed wiring board - Google Patents

Abstract

PURPOSE:To set a metal layer as a terminal in the case of electrically plating a metal plate inserted into an insulating board by electrically connecting a metal layer to the plate with a conductive passage secured to the board. CONSTITUTION:An insulating board in which resin is immersed to a base material, dried and cured is employed as a resin board 1 for forming a printed circuit board. A metal layer 2 arranged on the surface of the board 1, holes 5 passed through the board 1 and the layer 2, and a conductive passage 7 for electrically connecting the layer 2 formed by solidifying adhesive having conductivity to a metal plate 6 between the plate 6 inserted to place an electric component into the hole 5 and the inner wall of the hole 5 are provided. Thus, a terminal necessary to electrically plate the plate 6 can be set on the layer 2 arranged on the board 1.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to printed wiring boards.

In particular, the present invention relates to a printed wiring board equipped with a metal plate having heat dissipation properties and suitable for mounting electronic components, and more specifically to a semiconductor chip carrier.

[Conventional technology]

Conventionally, as shown in FIGS. 5 and 6, for example, there has been known a printed wiring board in which a metal plate 6 is inserted into an insulating substrate vi1 for heat radiation. For rust prevention and bonding of semiconductor chips, metal +ffl 6 is plated with gold or silver, and electronic components, especially semiconductor chips, are directly mounted on top of this, and the heat generated from these is radiated. The electrical characteristics of electronic components can be made to function stably. That is, a part or all of the metal plate 6 is inserted into the first hole 3 in the insulating substrate 1.
The printed wiring board is inserted into a first hole 3 of a through hole 5 consisting of a second hole 4 which is smaller than the second hole 4, and the second hole 4 forms a recess for mounting an electronic component.

The metal plate 6 shown in FIG. 5 and the insulating substrate 1 are fixed with an insulating adhesive 9, and the metal plate 6 shown in FIG. It is done in manga resin. Therefore, in either case, the loaded metal plate 6 is electrically insulated from the metal layer 2 on the surface of the insulating substrate 1. For this reason, the terminals necessary for electroplating the metal plate 6 with gold or silver cannot be set to gold 171N2. Conventionally,
As a countermeasure against this, gold or silver electroplating is performed after electrically connecting the metal layer 2 on the surface of the insulating base it and the charged metal plate 6 with a through-hole plating layer formed by electroless plating. However, in such a structure, an extra process of through-hole plating is required to electrically connect the metal plate 6 charged for heat dissipation and the metal layer 2 serving as the terminal, and the plating solution used at this time requires an extra step of through-hole plating. Insulating substrate l, metal vi6, etc. are violated.

To prevent this, masking processing must be performed, which increases the number of steps and hinders rational production.

[Problems to be Solved by the Invention] To provide a printed wiring board for mounting electronic components in which terminals necessary for electroplating a loaded metal plate can be set on a metal layer provided on an insulating substrate. It is in.

[Means to solve the problem]

In order to solve the above-mentioned problems, a printed wiring board for mounting electronic components according to the present invention includes an insulating substrate made of resin, a metal layer disposed on the surface of the insulating substrate, and a metal layer that penetrates the insulating substrate and the metal layer. A conductive adhesive is solidified between a metal plate inserted into the hole to mount an electronic component and the inner wall of the hole, and the metal layer and the metal plate are electrically connected. It is characterized by being separated from the conductive path connected to the conductive path.

A detailed explanation will be given below based on the drawings. 1 and 2 show a printed wiring board according to one embodiment of the present invention, and FIG. 4 shows a printed wiring board according to another embodiment. Note that FIG. 3 is a sectional view of the original plate before the metal plate 6 constituting the printed wiring board of FIG. 2 is inserted. The resin substrate 1 constituting the printed wiring board shown in FIG. 2 is an insulating substrate obtained by curing a prepreg resin obtained by impregnating a base material with a resin and drying it. Here, the resin for the insulating substrate 1 is preferably a resin that has excellent heat resistance and moisture resistance, and has high purity, especially low ionic impurities. Specifically, epoxy resin, polyimide resin, fuso resin, modified PPO resin, etc. are suitable. As the base material for the insulating base temporary 1, an inorganic material such as glass fiber is preferable to paper because it has better moisture resistance and heat resistance. The thickness of the insulating substrate 1 is not particularly limited and may be any conventional thickness.

The metal layer 2 disposed on the surface of the insulating substrate 1 includes copper,
It can be suitably selected from aluminium, iron, nickel, stainless steel, etc., and among them, copper is preferred because of its excellent conductivity. The thickness of this metal layer 2 is also not particularly limited and may be any conventional thickness. When disposing this metal N2 on the surface of the insulating substrate 1,
For example, various methods such as electroless plating or adhesion of metal foil can be used.

The hole 5 penetrating the insulating substrate 1 and the metal layer 2 consists of a first hole 3 for inserting the metal plate 6 and a smaller second hole 4 following it, as shown in FIG. As shown in FIG. 1 and FIG. 3, each hole forms a square prism. The rectangular prism hole shape is superior in terms of the material yield of metal plates 6 and electronic components mounted using these holes, good handling, and high heat dissipation efficiency. is not particularly limited, and may be a cylinder or a truncated pyramid.

The metal plate 6 is inserted into the first hole 3, and the metal plate 6
The shape may be such that a gap is created between the hole 3 and the inner wall surface of the l-th hole 3, and a portion thereof may protrude from the insulating group Fi1. The metal plate 6 has a hole, aluminum,
Metal materials such as zinc, iron, and nickel can be used, and copper and aluminum are preferable because they have high heat dissipation properties.

between the metal plate 6 and the opposing inner wall surface of the first hole;
The conductive path 7 formed over the entire length is a solidified conductive adhesive, and electrically connects the metal plate 6 and the metal layer 2 disposed on the surface of the insulating base material 1. It is set up to do so. At the same time, the metal plate 6 is fixed to the insulating base material l. Note that if the conductive path 7 is formed between the side surface of the metal plate 6 and the opposing inner wall surface of the first hole 3 and electrically connects the metal plate 6 and the metal layer 2, the shape can be improved. It is not limited to a certain location. As the conductive adhesive, a resin containing metal powder such as gold, silver, copper, or aluminum and having excellent heat resistance such as epoxy resin, polyimide resin, phenol resin, or silicone resin can be used as a binder. Particularly preferred is an epoxy resin adhesive containing resin because of its great adhesiveness and high conductivity.

The printed wiring board of FIG. 4, which is another example, is characterized by a circuit pattern 2a in which a circuit is formed of metal N2 disposed on an insulating substrate 1, which passes through the insulating substrate 1 and the circuit board 2a. First hole 3 of hole 5 followed by smaller hole 4
A conductive band 8 is formed on the inner wall surface of the insulating substrate 1, and is electrically connected to the circuit pattern 2a provided on the surface of the insulating substrate 1.

Therefore, the metal plate 6 inserted into the first hole 3 is fixed only at the bottom of the first hole 3 via the conductive path 7 formed by solidifying the conductive adhesive. When the conductive band 8 is formed on the inner wall surface of the through hole 5 in this way, the position of the conductive path 7 can be any location between the inner wall surface of the first hole 3 and the metal plate 6 facing each other. In comparison with the embodiment shown in FIG. 2, it is easier to charge and fix the metal VI6. Note that the conductive band 8 can be formed using a method such as electroless plating in the same process as the formation of the circuit pattern 2a.

(Function) In contrast to the conventional method of electrically connecting the metal plate inserted into the insulating substrate and the metal layer on the surface of the insulating substrate by through-hole plating, the present invention provides an electrical connection between the inserted metal plate 6 and the metal layer on the surface of the insulating substrate. For electrical connection with the metal layer 2 or circuit pattern 2a disposed on the surface of the substrate 1, the metal plate 5 to be loaded is connected to an insulating substrate vi. This is done at the same time as the fixing by means of a conductive path 7 made of a solidified conductive adhesive used for fixing to the substrate 1.

〔Effect of the invention〕

Conventionally, through-hole plating must be performed to electrically connect the loaded metal plate 6 and the metal layer 2 or circuit pattern 2a on the surface of the insulating substrate 1. In addition, the insulating substrate 1, metal plate 6, etc. are damaged by the plating solution at this time, which requires a masking process. Since the metal N2 and the metal plate 6 are electrically connected by the conductive path 7 which is fixed to the insulating substrate 1, the metal layer 2 is connected to the terminal when electroplating the metal plate 6. It can be set as .

[Brief explanation of the drawing]

FIG. 1 is a plan view of a printed wiring board according to an embodiment of the present invention, FIG. 2 is an AB sectional view of the printed wiring board of FIG. It has a metal layer! FIG. 4 is a cross-sectional view of another embodiment of the present invention, and FIGS. 5 and 6 are cross-sectional views of a conventional example of a printed wiring board into which a metal plate is inserted. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Metal layer, 2a... Circuit pattern, 3... First hole, 4...
2nd hole, 5... Through hole, 6... Metal plate, 7... Conductive path, 8... Conductive band, 9... Adhesive layer 1 Figure 13! Figure I4 Procedural Amendment (Method) Indication of the case Year 1999 Patent order No. 15666 Name of invention Name of printed wiring board amendment Relationship to the case Patent applicant address Name of 1048 Kadoma, Kadoma City, Osaka Prefecture
(583) Matsushita Electric Works Co., Ltd. Representative Toshio Miyoshi Contents of the amendment (1) "Printed wiring board" in the third line of page 1 of the specification was changed to "
Corrected to "Printed wiring board". June 26, 2nd year of the Heikai era (shipment date) Subject to amendment

Claims (3)

[Claims] (1) An insulating substrate made of resin, a metal layer disposed on the surface of this insulating substrate, a hole penetrating the insulating substrate and this metal layer, and a metal plate inserted into this hole for mounting electronic components. and a conductive path that electrically connects the metal layer and the metal plate, the conductive path being formed by solidifying a conductive adhesive between the inner wall of the hole and the inner wall of the hole. Printed wiring board for. (2) A printed wiring board for mounting electronic components according to claim 1, wherein the conductive path is formed over the entire length between the metal plate and the opposing inner wall surface of the hole. . (3) The printed wiring board for mounting electronic components according to claim 1, wherein the conductive path is formed between a side surface of the metal plate and an opposing inner wall of the hole.