JP3072189B2 - Heat dissipation board for semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation board for a semiconductor device on which a semiconductor chip can be mounted, and more particularly, to a heat dissipation board for a semiconductor device which can efficiently dissipate heat generated from the semiconductor chip.

[0002]

2. Description of the Related Art In recent electronic devices, the amount of heat generated by a semiconductor chip tends to increase due to the increase in the amount of information and the diversification of demand, and the heat generation of a semiconductor chip tends to increase. It is customary to attach various heat dissipation boards to the semiconductor device.

Conventionally, a substrate made of a ceramic material such as aluminum nitride, silicon nitride, or silicon carbide has been used as the heat dissipation substrate. However, these substrates have no bonding defects such as peeling due to the difference in thermal expansion with the semiconductor chip to be mounted, and although some progress can be seen,
It is necessary to improve the thermal conductivity (so-called heat dissipation) and the lightness, and it has not been able to sufficiently respond to the demand for higher density of the semiconductor device.

[0004] On the other hand, there have been proposed various heat radiating substrates in which the above-mentioned drawbacks of the ceramic substrate, that is, heat radiating property and lightness are improved. For example, a silicon carbide substrate having a fin structure (Japanese Patent Application Laid-Open No. 60-241239) and a ceramic substrate in which a plurality of pin-shaped members are joined (Japanese Patent Application Laid-Open No. 3-79064) are exemplified.

[0005] The conventional heat-dissipating substrates proposed in these publications have excellent heat-dissipating properties of the heat-dissipating substrate as compared with a heat-dissipating substrate having only a flat plate, since the heat-dissipating portions each have a fin structure. It is also excellent in lightness.

[0006]

However, in the case of the above-mentioned conventional heat radiation substrate, the silicon carbide substrate having a fin structure has a problem that its members are hard, brittle and extremely poor in workability due to its dense body. there were. On the other hand, a substrate in which a plurality of pin-shaped members are joined has excellent heat radiation compared to a case of only a flat plate, but there is a limit in obtaining heat radiation enough to cope with high density of a semiconductor device. .

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heat radiation board which can overcome the problems of the prior art, and in particular, can sufficiently cope with a high density of a semiconductor device while maintaining excellent light weight of a fin structure. Provided is a heat dissipation board for a semiconductor device having excellent heat dissipation and excellent workability.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned objects, and as a result, the above-mentioned object has been advantageously achieved by forming a heat-radiating substrate for a semiconductor device as follows. The present inventors have found out that they can be solved, and have arrived at the present invention.

That is, according to the present invention, in a heat dissipation board for a semiconductor device on which a semiconductor chip can be mounted, the surface on which the semiconductor chip is mounted is constituted by a flat plate made of a silicon carbide dense body, and the other surface is formed by a silicon carbide porous body. A heat dissipation board for a semiconductor device, comprising: a plurality of hollow pin-shaped members made of a solid body;

[0010]

The heat dissipation board for a semiconductor device according to the present invention is characterized in that it is composed of a flat plate made of a dense silicon carbide body and a heat dissipation fin having a large number of hollow pin-shaped members made of a porous silicon carbide body. It is in.

With this configuration, the airtightness of the semiconductor chip can be maintained and the weight thereof can be reduced, and the semiconductor chip has excellent heat dissipation that can sufficiently cope with the high density of the semiconductor device. It is possible to provide a heat dissipation board for a semiconductor device which is excellent in workability.

FIG. 1 is a view showing an example of a heat dissipation board for a semiconductor device according to the present invention. Reference numeral 1 in the drawing is a flat plate made of a dense silicon carbide body, which is a member on which a semiconductor chip is mounted. The reason why the material of the flat plate 1 is a silicon carbide dense body is that when the semiconductor chip is mounted, the semiconductor chip is prevented from coming into contact with air, and the airtightness of the semiconductor chip can be effectively maintained. In addition, on the semiconductor chip mounting surface of the flat plate 1, a Ni or Au plating layer 2 can be arbitrarily provided in order to improve the adhesion of the semiconductor chip to the substrate.

A radiation fin 3 made of a porous silicon carbide material having a porosity of 10 to 40% is joined to the flat plate 1 on the side opposite to the semiconductor chip mounting surface. This radiation fin 3
The reason why a porous material having a porosity of 10 to 40% is used is that the workability of the substrate can be greatly improved although the thermal conductivity is slightly lower than that of a dense material.

The radiating fin 3 comprises a base 3a and a number of hollow pin-shaped members 3b protruding from the base 3a. The reason why a large number of hollow pin-shaped members 3b are protruded is that the surface area of the radiation fins 3 is about twice as large as that of the conventional solid pin-shaped members, and the heat radiation of the substrate is improved by about 1.5 to 2.0 times. It is. The hollow pin-shaped member 3b may have any cross-sectional shape as long as it has a pin shape, and may have, for example, a triangular cross-section or a square cross-section. In particular, a square cross-section is preferable in consideration of extrusion moldability.

As described above, the heat dissipation board for a semiconductor device of the present invention is provided with the heat dissipation fins having the above-described structure, and thus has excellent heat dissipation properties that can sufficiently cope with high density of the semiconductor device. Therefore, when a semiconductor chip is mounted on this substrate, heat generated from the semiconductor chip can be efficiently dissipated, and an error due to a rise in the temperature of the semiconductor chip can be reliably prevented.

Further, a heat dissipation board for a semiconductor device according to the present invention comprises:
Since the radiation fins of porous silicon carbide having a porosity of 10 to 40% are used, it is possible to reduce the weight of the radiation substrate, and it is easier to process than a dense body. Productivity can be greatly improved.

Next, the heat dissipation board for a semiconductor device of the present invention comprises:
For example, it can be manufactured by the following method (see FIG. 2). First, after adding and kneading a binder to silicon carbide powder, extrusion molding is performed to obtain a molded body having a predetermined shape (see FIG. 2A). As the silicon carbide powder, it is preferable to use a mixed powder of powders having an average particle diameter of 0.2 to 8 μm. This is because the porosity of the porous body can be variously controlled by mixing powders having different average particle sizes. As the binder, a known resin such as methylcellulose can be used.

Next, the compact is bonded to a flat plate made of a dense silicon carbide body, degreased in a firing furnace, and then fired to obtain a sintered body having a predetermined shape (see FIG. 2 (b)). . This bonding is performed, for example, by using silicon carbide powder (average particle size 0.2 to 8 μm).
m) to resin (α-terpineol and methylcellulose)
And using a paste having an appropriate viscosity.

Then, cuts are made in the vertical and horizontal directions in the portion where the heat radiation fins of the sintered body are formed, as shown in FIG. By this notch processing, a heat dissipation board for a semiconductor device having a shape in which a number of hollow pin-shaped members protrude from the heat dissipation fin portion can be obtained (see FIG. 2C).

The semiconductor chip bonding surface of the substrate obtained as described above may be subjected to Ni plating or Au plating as necessary to improve the adhesiveness of the semiconductor chip to the substrate. As a result, the reliability of the semiconductor device can be improved.

[0021]

[Example] After adding a binder to SiC powder (mixed powder of 0.2 μm and 8 μm in particle diameter) and kneading it, extrusion molding was performed, and 30 × 30 mm, length 200 mm, square 2 mm, wall thickness 0.3 m.
m was obtained. Next, the molded body was cut out at intervals of 15 mm, and a SiC flat plate (30
× 30 × 2 mm) and degreased and fired in a firing furnace. Then, a 10 mm deep cut for forming a pin-shaped member is made in the heat radiation fin forming portion (lattice portion), while Ni plating (film thickness 2 μm) and Au plating (film thickness 0.25 μm) to produce a heat dissipation substrate for a semiconductor device.

A semiconductor chip was bonded to the heat-radiating substrate for a semiconductor device with Ni and Au plating thus obtained, and its thermal characteristics were examined. As a result, heat dissipation is 1.
It was confirmed that it improved by 8 times.

Further, the time required for making a 10 mm deep cut in the lattice portion was measured to examine the workability of the heat dissipation substrate. As a result, while the processing time of the conventional substrate made of dense SiC was 21 hours and 20 minutes, the processing time of the substrate of the present invention was 1 hour and 4 minutes, and the workability of the substrate could be greatly improved. I understood.

Further, the weight of the radiating fin was measured to examine the weight reduction of the substrate. As a result, conventional SiC
The weight of the heat radiation fin of the present invention was 15.3 g, while the weight of the heat radiation fin made of a dense body was 21.9 g. Thus, it was found that the weight of the substrate could be reduced.

[0025]

As described above, the heat dissipation board for a semiconductor device according to the present invention is a heat dissipation fin having a flat plate made of a dense silicon carbide body and a large number of hollow pin-shaped members made of a porous silicon carbide body. , So that it is possible to maintain the airtightness of the semiconductor chip and to reduce the weight, and also has excellent heat dissipation that can sufficiently cope with the high density of the semiconductor device, and also to the workability. An excellent heat dissipation substrate for a semiconductor device can be provided.

[Brief description of the drawings]

FIG. 1 shows an example of a heat dissipation board for a semiconductor device of the present invention.
(a) is a front view and (b) is a sectional view.

FIG. 2 is a diagram illustrating an example of a method for manufacturing a heat dissipation board for a semiconductor device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat plate 2 Ni, Au plating layer 3 Heat radiation fin 3a Base 3b Hollow pin-shaped member

Claims (1)

(57) [Claims] In a heat dissipation board for a semiconductor device on which a semiconductor chip can be mounted, a surface on which the semiconductor chip is mounted is constituted by a flat plate made of a dense silicon carbide body, and the other surface is made of a porous silicon carbide body. A heat dissipation board for a semiconductor device, comprising: a plurality of hollow pin-shaped members formed by projecting heat dissipation fins.