JPH05259650A - Printed wiring board - Google Patents

Abstract

PURPOSE:To obtain a high heat radiation type printed wiring board that has a highly accurate and reliable function with simple processes. CONSTITUTION:A printed wiring board comprises a heat-radiation type metal support plate 1; rigid printed wiring board bodies 2 and 2' which are laminated and arranged on both main surfaces of the plate 1 in an integrated manner; and a flexible wiring plate 5, projecting from the peripheral edges of the bodies 2 and 2' and the support plate 1, for electrically connecting wiring layers 2a and 2b of the bodies 2 and 2'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board,
In particular, it relates to a printed wiring board having heat dissipation.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become lighter, thinner, shorter, and smaller, high-density wiring or multi-layer wiring structure has been attempted in printed wiring boards. Further, it is expected that the circuit function or the reliability will be improved, and it is also known that the printed wiring board is provided with heat dissipation as one means thereof. That is, as a high heat radiation type printed wiring board, a required circuit pattern layer (wiring layer) is formed on both main surfaces of a heat radiation metal supporting plate (metal plate) 1 as shown in FIG. Rigid printed wiring board bodies 2 and 2'having 2a and 2b respectively are integrally laminated and arranged, and circuit pattern layers 2a and 2b of both printed wiring board bodies 2 and 2'are through-hole connected 3 The configuration consists of Such a high heat radiation type printed wiring board is generally manufactured as follows. That is, the required area (position) of the heat-dissipating metal support plate 1
A through hole for forming a through hole is formed in advance, and a hard printed wiring board body 2, which has the required circuit pattern layers 2a and 2b on both main surfaces with the heat dissipation metal supporting plate 1 sandwiched therebetween. After aligning, stacking, and arranging the circuit element plates and prepregs that respectively constitute 2 ', they are heated and pressed to be integrated. Next, the areas (positions) of the printed wiring board bodies 2 and 2'which are laminated and integrated in correspondence with the through holes for forming through holes formed in the heat-dissipating metal supporting plate 1
Then, through holes are formed by, for example, drilling.
Then, for example, chemical plating and electroplating are selectively performed on the formed inner wall surface of the through hole to form a through hole connection 3 between the circuit pattern layers 2a and 2b to obtain a required high heat radiation type printed wiring board. There is.

[0003]

However, in the case of the high heat dissipation type printed wiring board having the above structure, there are the following inconvenient problems. First of all, it is necessary to form a through hole in a required area of the heat-dissipating metal supporting plate 1 so that the through-hole connecting portion 3 can be formed with a sufficient margin. Further, since Invar alloy (Fe-Ni) or the like having high heat dissipation is inferior in mechanical workability, it is difficult to form a through hole, and it is difficult to use it as the metal supporting plate 1. In particular, when a high heat dissipation type printed wiring board of this kind is formed with high density wiring or multi-layer wiring, the through holes are also made smaller in diameter, so that it is more difficult to form the through holes with high accuracy. .. Secondly, the printed wiring board bodies 2 and 2'must be positioned, laminated and arranged with high precision on both main surfaces of the metal support plate 1 having a heat radiation property, but this operation is also required. It is complicated and difficult to integrate in a highly accurately aligned state. Thirdly, when the printed wiring board bodies 2 and 2'are heated, pressed and integrated with the heat-dissipating metal supporting plate 1 sandwiched therebetween, the through hole inner wall surface region where the metal supporting plate 1 is bored is formed. (Fig. 3
In the area A), the resin does not sufficiently flow and voids are likely to occur, so it is necessary to apply resin or the like to the inner wall surface of the through hole in advance.

As described above, the conventional high heat radiation type printed wiring board is manufactured by the manufacturing means itself or by the manufacturing means.
In reality, there is a problem in terms of accuracy or functional reliability, and it is not practically satisfactory.

The present invention has been made in view of such circumstances, and an object thereof is to provide a high heat radiation type printed wiring board which is obtained by a simple process and which exhibits a highly accurate and highly reliable function. To do.

[0006]

SUMMARY OF THE INVENTION A printed wiring board according to the present invention comprises a heat-dissipating metal supporting plate and a rigid printed wiring board body integrally laminated and arranged on both main surfaces of the metal supporting plate. And a flexible wiring board projecting from the peripheral end faces of the printed wiring board body and the metal supporting plate to electrically connect the wiring layers of both printed wiring board bodies.

[0007]

In the printed wiring board of the present invention, the electrical connection between the rigid printed wiring board bodies integrally laminated and arranged on both main surfaces of the heat-dissipating metal supporting plate is based on the so-called through-hole connection. Since it does not exist, problems such as complicated work, difficulty in highly accurate positioning, and the like, and problems such as deterioration of insulation due to existence / remaining voids can be easily solved. That is, the printed wiring board according to the present invention has good heat dissipation due to the metal supporting plate integrally provided with wiring layers on both sides, and the electrical connection between the wiring layers is made by a flexible wiring board. I am wearing Therefore, not only the complicated steps involved in forming the through-hole connection can be eliminated, but also the wiring density or the mounting density can be improved, and in addition, the reliability of the circuit function can be maintained.

[0008]

Embodiments of the printed wiring board according to the present invention will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view showing an example of the essential structure of a printed wiring board according to the present invention. Reference numeral 1 denotes a heat-dissipating metal support plate (metal plate) 1, for example, an invar having a thickness of about 1 to 2 mm. The alloy plates (Fe-Ni), 2 and 2'are integrally laminated on both main surfaces of the metal supporting plate 1 with an adhesive layer 4 interposed therebetween.
Rigid printed wiring board book, 2
a and 2b are circuit pattern layers (wiring layers) which form the main part of the front printed wiring board bodies 2 and 2 ', and 5 is a circuit pattern layer 2 which forms the main part of the printed wiring board bodies 2 and 2'.
It is a flexible wiring board that electrically connects the layers a and 2b. The flexible wiring board 5 has connection wiring regions 5a and 5b on one main surface independently of the signal wiring layer and the power wiring layer, as shown in plan view in FIG.
On the other main surface, the connection wiring regions 5a 'and 5b' are provided independently of the other signal wiring layers and power supply wiring layers, and the printed wiring board bodies 2 and 2'are formed. When each of the circuit pattern layers 2a and 2b forming the main part has four layers, one flexible wiring board 5 can be used for a required connection.

Such a high heat radiation type printed wiring board is generally manufactured as follows. That is, align the prescribed circuit board and prepreg.
After stacking and arranging, the flexible printed circuit board 5 is terminated by heating, pressurizing and integrating to form the hard printed wiring board bodies 2 and 2'having the required circuit pattern layers 2a and 2b, respectively. The side is the circuit pattern layer 2
Among a and 2b, they are arranged so as to be directly or through-hole connected to a required circuit pattern, and heated and pressurized to be integrated. In this way, the two rigid printed wiring board bodies 2 and 2 ′ first constitute the printed wiring board bodies 2 and 2 ′ which are connected and integrated by the flexible wiring board 5. Next, a metal on which one side of each of the printed wiring board bodies 2 and 2'connected / integrated by the flexible wiring board 5 is previously attached and formed with, for example, an epoxy resin adhesive layer 4 A desired printed wiring board can be obtained by aligning on the surface of the support plate 1 and heating and pressurizing to integrate them.

In the above, the case where the circuit pattern layers 2a and 2b of the printed wiring board bodies 2 and 2'each have four layers has been exemplified, but the circuit pattern layers 2a and 2b may have a further multilayer structure or a circuit pattern. The number of layers 2a, 2b need not be the same. Further, the structure of the flexible wiring board 5 for electrically connecting the circuit pattern layers 2a and 2b of the printed wiring board bodies 2 and 2'is not limited to the above-mentioned example, and may be a single-sided type or a multi-layered type. May be.

[0012]

As described above, the printed wiring board according to the present invention retains the high heat dissipation of a so-called metal core substrate, while at the same time, does not require complicated work operation and is highly reliable. Since the density wiring can be easily achieved, it can be said that the printed wiring board for mounting has many practical advantages in terms of downsizing the circuit device, improving the circuit function, and increasing the capacity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a main part of a heat dissipation type printed wiring board according to the present invention.

FIG. 2 is a plan view showing a wiring example of a flexible wiring board forming a connection portion of the heat dissipation type printed wiring board according to the present invention.

FIG. 3 is a cross-sectional view showing a main part configuration of a conventional heat radiation type printed wiring board.

[Explanation of symbols]

 1 ... Heat-dissipating metal supporting substrate 2, 2 '... Printed wiring board main body 2a, 2b ... Circuit pattern layer (wiring layer) 3 ... Through hole connecting portion 4 ... Adhesive layer 5 ... Flexible wiring board 5a: signal wiring layer 5b: power wiring layer

Claims (1)

[Claims] 1. A heat-dissipating metal support plate, a rigid printed wiring board body integrally laminated and arranged on both main surfaces of the metal support plate, and a periphery of the printed wiring board body and the metal support plate. A printed wiring board, comprising: a flexible wiring board projecting from an end face and electrically connecting wiring layers of both printed wiring board bodies.