JPH04255289A - Metal base wiring board - Google Patents

Abstract

PURPOSE:To enable a metal base wiring board to be more enhanced in degree of integration by a method wherein a wiring board is divided into a heat releasing electric component mounting region and an electric component mounting region where an electric component whose characteristics are susceptive to temperature rise is mounted, and a heat insulating means such as a slit-like hole or holes arranged in continuation is provided onto the wiring board between the regions concerned. CONSTITUTION:An electric component 6c of high power is soldered to wirings 3a and 3b provided onto a metal base wiring board 6. Slit-like holes 8a, 8b, and 8c are provided around a resistor 6b susceptible to temperature in resistance to serve as a heat insulating means. The heat released from an electric component 6c of high power is primarily diffused to the whole through the metal board 6, and the slit-like holes 8a, 8b, and 8c are made to prevent heat from diffusing, whereby the thermal effect of the heat released from the electric component of high power on the resistor 6b can be reduced to a minimum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board on which electronic components are mounted, and more particularly to a metal-based wiring board in which an insulating layer is formed on one or both sides of a metal plate.

0002

[Prior Art] In general, this type of wiring board has superior thermal conductivity and mechanical strength compared to wiring boards using ordinary resin printed circuit boards or alumina ceramic substrates, and is a power source for devices. It has come to be widely used as a control wiring board. FIGS. 3A and 3B are a plan view and a cross-sectional view taken along the line C-C of a metal wiring board showing an example of the conventional method.

Conventionally, as shown in the figure, this metal-based wiring board is made by coating the surface of a metal substrate 1a with an insulating material to form an insulating layer 2b, and coating the insulating layer 2b with a conductive material. Wiring 3, through hole 4, terminal 5 and resistor 6b
was forming. An electrical component 6a was mounted on the terminal 5 of this metal base wiring board.

0004

[Problems to be Solved by the Invention] This conventional metal-based wiring board allows high-power components to be mounted and used because the generated heat is diffused throughout the board and is not concentrated at a single point at a high temperature. It is. On the other hand, the temperature of the entire board rises, and it is necessary to avoid mounting electrical components that are sensitive to temperature on the same board, which is a difficult point in integrating circuits.

[0005] An object of the present invention is to provide a metal-based wiring board that eliminates such drawbacks.

[0006]

[Means for Solving the Problems] The metal-based wiring board of the present invention divides the board into an electrical component mounting area that generates heat and an electrical component mounting area whose characteristics are sensitive to temperature rise, and between these areas, For example, it is characterized in that a heat insulating means such as a slit-like hole, a plurality of holes arranged in series, or a band-like insulating layer with heat-insulating properties is formed on the substrate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are a plan view and a sectional view taken along the line AA of a metal base wiring board showing an embodiment of the present invention. As shown in the figure, this metal base wiring board is manufactured by pasting a ceramic plate 2a, which is an insulating material, on a metal substrate 1a, and using a screen printing method, wiring 3a, 3b, resistor 6b,
were formed sequentially. A high power electrical component 6c is soldered to the wirings 3a and 3b on this metal base wiring board. Another advantage is that slit-shaped holes 8a, 8b, and 8c, which serve as heat insulating means, are formed around the resistor 6b, whose resistance value is likely to be affected by temperature.

As described above, unless the slit-shaped holes 8a, 8b, and 8c are provided around the resistor 6b, the heat generated in the high-power electrical component 6c will mainly pass through the metal substrate 6 and be distributed throughout the body. However, the slit-shaped holes 8a, 8b, and 8c prevent the heat from spreading, and the resistor 6
b can minimize the influence of heat generated from the high-power electrical component 6c.

By the way, when this metal base wiring board was used to install a power transistor with a power consumption of about 1.2W as a high-power electrical component 6c, the board was installed vertically at a room temperature of 25°C in a windless state. When the temperature was measured, the surface temperature of the power transistor mold rose to 45°C. At this time, the PN junction temperature of the transistor has reached approximately 100°C. 26℃ in the resistor part
As a result, we were able to lower the temperature by 7°C compared to conventional methods. That is, assuming that the temperature coefficient of resistance of the resistor is 300 ppm/° C., this corresponds to a change in resistance value of 0.21% due to temperature change, which means that the stability has been improved by 0.21%.

In this example, the holes were formed in the shape of slits, but the same effect could be obtained even if the holes were formed side by side with the same diameter as the width of the slit.

FIGS. 2(a) and 2(b) are a plan view and a BB sectional view of a metal base wiring board showing another embodiment of the present invention. This metal base wiring board, as shown in the same figure,
An electrical component 6c that generates heat is formed on an insulating layer 2b made of polyester as a base material, for example, on an aluminum substrate 1b.
The high power section region 9 is divided into the control section region 7 where the electric components 6a, 6e and the resistor 6b whose characteristics are sensitive to temperature are mounted. This is because a slit-shaped hole 8d is formed. As a result, the same results as in the above-mentioned example could be obtained.

This embodiment can also be applied to cases where an insulating material is provided on both sides of the substrate, and furthermore, it can be applied to a case where an insulating material is provided on both sides of the substrate. If this slit-shaped hole is filled with the following, there is an advantage that the mechanical strength can be further improved.

[0014]

As explained above, the present invention provides heat shielding means between the high-power electrical component mounting area and the electrical component mounting area whose characteristics are sensitive to temperature.
This has the effect of providing a metal-based wiring board that can be more integrated.

[Brief explanation of the drawing]

FIG. 1 is a plan view and an AA cross-sectional view of a metal base wiring board showing an embodiment of the present invention.

FIG. 2 is a plan view and a BB sectional view of a metal base wiring board showing another embodiment of the present invention.

[Fig. 3] A plan view and C of a metal wiring board showing a conventional example.
-C sectional view.

[Explanation of symbols]

1a Metal substrate 1b Aluminum substrate 2a Ceramic plate 2b Insulating layer 3, 3a, 3b Wiring 4 Through hole 5 Terminal 6a, 6c, 6d Electrical component 6d Resistor 7 Control area 8a, 8b, 8c, 8d Slit hole 9
High power area

Claims (4)

[Claims] Claim 1: In a metal-based wiring board, in which an insulating layer is formed on the surface of the metal board, and a wiring pattern made of a conductive material, terminals for attaching electrical components, and through holes are formed on this insulating layer, the electricity generated 1. A metal-based wiring board, characterized in that the board is divided into a component mounting area and an electrical component mounting area whose characteristics are sensitive to temperature increases, and a heat insulating means is formed between the areas. 2. The metal-based wiring board according to claim 1, wherein the heat insulating means is a slit-like hole formed in the board. 3. The metal-based wiring board according to claim 1, wherein the heat insulating means are holes formed in a line in the board. 4. Claim 1, wherein the heat insulating means is a band-shaped insulating layer with heat insulating properties embedded in the substrate.
The metal-based wiring board described.