JPH0418746A - Substrate for ic mounting - Google Patents

Abstract

PURPOSE:To obtain a light IC substrate with superior heat-resisting cycle characteristics by a method wherein the substrate is formed into a substrate for IC mounting use, which has a silicon carbide layer and Al layers which are respectively applied on both surfaces of this silicon carbide layer via each brazing metal layer. CONSTITUTION:Al layers 13A and 13B for circuit formation use are respectively applied on both surfaces of a silicon carbide layer 11 via brazing metal layers 12A and 12B. Moreover, Ni-plated layers 14A and 14B are respectively applied on each surface of the Al layers. As the layer 11 has a strong bonding strength to the brazing metal layers because of the nature of the material for the layer 11 and has a heat conductivity higher than that of the Al layers, a high heat dissipation property and a high bonding force are obtained by using the layer 11 as an insulating plate material. As the Al layers are used as a use for circuit formation or as a use for a base plate, a substrate is lightened as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to, for example, a high-output IC mounting board, and particularly to an IC mounting board with improved heat dissipation and reduced weight.

<Prior Art> Conventional IC mounting substrates of this type include, for example, an alumina substrate with Cu conductor thin plates adhered to the front and back surfaces. This problem can be solved by heating the Cu plate to a predetermined temperature after laminating the Cu plate onto the alumina substrate.
In mounting boards, Cu conductors are used as thin plate materials for circuit formation or base plates, so the weight of the board as a whole is large, and the coefficient of thermal expansion between the Cu conductors and the alumina board, etc. Because of the large difference, there was a problem in that the alumina substrate was prone to cracking in the thermal cycle test.

Therefore, an object of the present invention is to provide an IC mounting substrate that is lightweight and has excellent heat cycle resistance characteristics.

<Means for Solving the Problems> The present invention provides an I.
This is a board for C mounting.

<Function> Since the IC mounting board according to the present invention uses a thin aluminum plate instead of a thin Cu plate, the weight of the entire board can be reduced. In addition, since a silicon carbide substrate with high thermal conductivity is used and a thin aluminum plate is attached to this using a brazing material, stress caused by heating etc. can be alleviated, making it resistant to thermal cycle tests. It also has greater durability and a longer lifespan for the board.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an IC mounting board according to an embodiment of the present invention.

In this figure, 11 is a silicon carbide layer (S
iC substrate (for example, a silicon carbide-based sintered body plate), and an aluminum layer (or aluminum alloy N) 13A for forming a circuit on both sides of the silicon carbide [11] via brazing material layers 12A, 12B, 13B are respectively deposited.

This brazing filler metal is Al-5i type, Al-Ge type, Al
-Cu-based brazing material is used.

Furthermore, Ni plating N (or Cu plating layer) 14A, 1 is applied to each surface of these aluminum ji13A, 13B.
4B is coated.

In the thin substrate according to the above configuration, silicon carbide layer 11
has strong bonding strength with the Al-5i-based brazing pads 12A and 12B, and also has higher thermal conductivity than alumina (
The thermal conductivity of SiC is 35-270 W/mK, whereas that of Al2O3 is 15-20 W/rnK). Therefore, by using silicon carbide as the insulating plate material, high heat dissipation and high bonding strength can be obtained.

Also, Aluminum J! 13A and 13B are used for forming a circuit or for a base plate, and further contribute to reducing the weight of this board as a whole. For example, the aluminum layers 13A and 13B have a thickness of 0.2 to 0.4. m
m, and the aluminum density is 2.7 to 2.8 g/
The conventional Cu conductor density is about 8.cm3.
It is about 9 to 9.0 g/cm".

The brazing filler metals 112A and 12B can be plastically deformed even during a thermal cycle test, and the relative difference between the aluminum N15A and N13B and the silicon carbide layer 11 is based on the difference in thermal expansion coefficient. It absorbs and alleviates expansion and contraction. From this point of view as well, the heat cycle resistance characteristics are improved.

<Effects> As described above, according to the present invention, it is possible to reduce the weight of the entire board. Moreover, cracks and the like do not occur in the silicon carbide layer, and the heat cycle resistance characteristics of the entire substrate are improved. Further, the bonding strength between the aluminum layer and the silicon carbide layer is also increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic structure of an IC mounting board according to an embodiment of the present invention. 1t. 12A. 13A. 14A. 2B 3B 4B

Claims (1)

[Claims] 1. A substrate for IC mounting, comprising a silicon carbide layer and an aluminum layer deposited on both sides of the silicon carbide layer via a brazing material layer.