JPH05145207A - Flexible printed board - Google Patents

Abstract

PURPOSE:To obtain a heat-dissipating function from a simple structure without providing a heat dissipater such as metal heat-dissipating plate or fins separately in a flexible printed board for arranging wiring conductor and chip parts. CONSTITUTION:The title board is constituted by an alloy layer 2 composed of iron-chromium allay containing aluminum and by an aluminum dioxide layer 3 formed from the alloy layer 2 on the surface 2A of this alloy layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed board on which wiring conductors and chip parts are arranged.

[0002]

2. Description of the Related Art Recent electronic devices have been rapidly miniaturized, lightened, thinned, and highly integrated and mounted. 58-
A printed circuit board and a flexible printed circuit board disclosed in Japanese Patent No. 103161 are known.

4 and 5 show an example of this kind of flexible printed circuit board. As shown in the figure, a chip component 102 is mounted on a film substrate 101 made of a polyimide film made of resin, and a wiring conductor 103 made of copper foil is applied to a plurality of places by printing or the like. ing. Each wiring conductor 103 is connected to the chip component 102 by soldering.

[0004]

However, the wiring conductor 103 and the chip component 10 provided on the film substrate 101 are not provided.
The film substrate 101 is heated by the heat generated from No. 2, but since a polyimide film (resin) is used as the material of the film substrate 101, the heat dissipation function is insufficient. In order to supplement this heat dissipation function, the film substrate 1
It is necessary to attach a metal heat radiating plate to 01 with bolts or to dispose fins on the device. That is, there is a problem in that a cooling device having a heat dissipation function needs to be provided in a device case separately from the film substrate 101 or bonded together, which complicates the structure and increases the number of parts.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a heat dissipation function with a simple structure without separately providing a heat dissipation device such as a metal heat dissipation plate or fins. It is to provide a flexible printed circuit board that can have the following.

[0006]

The invention according to claim 1 is
It is characterized in that it is composed of an alloy layer made of an iron-chromium alloy containing aluminum and an aluminum oxide layer formed from the alloy layer on the surface of the alloy layer.

The invention according to claim 2 is composed of a metal layer formed by vapor-depositing aluminum on an iron-chromium alloy, and an aluminum oxide layer formed from the aluminum on the aluminum surface of the metal layer. It is characterized by

According to the third aspect of the present invention, an aluminum oxide layer is formed and coated on the surface of a granular body made of an iron-chromium alloy containing aluminum.

[0009]

According to the present invention, when an electric component such as a wiring conductor is provided on the aluminum oxide layer of the flexible printed board, the aluminum oxide layer is heated by the heat generated from the electric component. The heat is
It is transmitted from the aluminum oxide layer to the alloy layer, and the aluminum oxide layer is cooled.

In the invention described in claims 2 and 3, the same operation as that of the invention described in claim 1 occurs.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a flexible printed circuit board according to a first embodiment of the present invention.

In the figure, reference numeral 1 is a flexible printed circuit board. This flexible printed circuit board 1 has an alloy layer 2 made of a stainless steel alloy of aluminum 5%, iron 75% and chromium 20%, and a surface 2A of the alloy layer 2. And an aluminum oxide layer 3 formed from the alloy layer 2 on the top. Aluminum 5%, Iron 75%, Chrome 20
% Alloy layer 2 made of 100% stainless steel alloy
By heating in the above temperature range, the aluminum oxide layer 3 containing aluminum oxide as a main component is generated.

The chip component 4 is mounted on the aluminum oxide layer 3, and the wiring conductor 5 made of copper foil is also mounted.
Is applied to a plurality of places by means such as printing.
Each wiring conductor 5 is connected to the chip component 4 by soldering 6, 6.

In the present embodiment, however, the heat generated from the wiring conductor 5 and the chip component 4 applied to the aluminum oxide layer 3 heats the aluminum oxide layer 3, but the heat is generated. 3 to the alloy layer 2, and the aluminum oxide layer 3 is cooled.

According to the above-mentioned structure, the wiring conductor 5 and the chip component 4 are provided on the aluminum oxide layer 3 of the flexible printed circuit board 1, and the heat generated from the wiring conductor 5 and the chip component 4 causes the aluminum oxide to be formed. Although the layer 3 is heated, the alloy layer 2 has excellent thermal conductivity and has a large heat dissipation function. Therefore, in order to dissipate the heat of the aluminum oxide layer 3, a heat dissipation device such as a heat dissipation plate or fins as in the conventional example should be provided. Without having a simple structure, it can have a heat dissipation function. As a result, it is possible to achieve high integration of chip components including mounting of power semiconductors. Further, it is not necessary to attach a metal heat radiating plate to the film substrate with bolts or the like as in the conventional example, and the overall thickness can be reduced. In addition, manufacturing is easy and cost reduction can be achieved.

Further, the aluminum oxide layer 3 has a dense structure, and therefore has a high insulating property and makes it difficult to cause electrical leakage. And the aluminum oxide layer 3
Since is generated from the alloy layer 2 on the surface 2A of the alloy layer 2, it has high adhesiveness with the alloy layer 2 and is difficult to peel from the alloy layer 2.

In this embodiment, the case where the aluminum oxide layer 3 is formed from the alloy layer 2 on one surface of the alloy layer 2 has been described, but the aluminum oxide layers 3 and 3 are formed on both surfaces of the alloy layer 2. Can also be generated.

Further, in the present embodiment, the alloy layer 2 is
It is composed of a stainless steel alloy of aluminum 5%, iron 75%, and chromium 20%, but is not limited to such weight ratio.

FIG. 2 shows a flexible printed circuit board according to the second embodiment of the present invention. In the figure, reference numeral 11 is a flexible printed circuit board. This flexible printed circuit board 11 comprises an iron-chromium alloy 12 and an aluminum 13
Is formed on the aluminum surface 13A of the metal layer 14, and an aluminum oxide layer 15 produced from the aluminum 13 is formed on the aluminum surface 13A of the metal layer 14. Second
According to the embodiment, the same effect as that of the first embodiment is obtained.

FIG. 3 shows a flexible printed circuit board according to the third embodiment of the present invention. In the figure, reference numeral 21 is a flexible printed circuit board. This flexible printed circuit board 21 is made of aluminum 5%, iron 75%, and chromium 20%.
% Stainless steel alloy 22 produced by heating to a temperature above about 1200 ° C., aluminum 5
%, Iron 75%, and chromium 20%, the surface of the grain structure of the stainless steel alloy 22 is formed and coated with the aluminum oxide layer 23. According to the third embodiment, the same effect as the first embodiment is obtained.

In this embodiment, the alloy 22 is
The aluminum content is 5%, the iron content is 75%, and the chromium content is 20%, but the weight ratios are not limited to these.

[0022]

As described above, according to the first aspect of the present invention, when an electric component such as a wiring conductor is provided on the aluminum oxide layer of the flexible printed circuit board, it is oxidized by the heat generated from the electric component. Although the aluminum layer can be heated, the heat dissipation function of the alloy layer, which has high thermal conductivity, is excellent. There is an effect that a heat dissipation function can be provided with a simple structure without being provided separately from the flexible printed circuit board or being bonded together.

According to the inventions of claims 2 and 3, the same effect as that of the invention of claim 1 is achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a flexible printed circuit board according to a first embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a main part of a flexible printed circuit board according to a second embodiment of the present invention.

FIG. 3 is an enlarged explanatory view of a main part of a flexible printed circuit board according to a third embodiment of the present invention.

FIG. 4 is a plan view of a conventional flexible printed circuit board.

FIG. 5 is a cross-sectional view of a conventional flexible printed circuit board.

[Explanation of symbols]

 1 Flexible Printed Circuit Board 2 Alloy Layer 2A Surface 3 Aluminum Oxide Layer

Claims (3)

[Claims] 1. An alloy layer (2) made of an iron-chromium alloy containing aluminum, and an aluminum oxide layer (3) produced from the alloy layer (2) on the surface of the alloy layer (2). A flexible printed circuit board characterized by being configured. 2. A metal layer (14) formed by vapor-depositing aluminum (13) on an iron-chromium alloy (12) and an aluminum surface (13A) of the metal layer (14) formed from the aluminum. A flexible printed circuit board comprising an aluminum oxide layer (15). 3. A flexible printed circuit board in which an aluminum oxide layer (23) is formed and coated on the surface of a granular body made of an iron-chromium alloy (22) containing aluminum.