JPS61280640A - Semiconductor device - Google Patents

Abstract

PURPOSE:To simplify the installation of a resin film and to make the film thinner for the improvement of the heat-radiating efficiency by a method wherein the resin thin film is formed by the dip method and covers the resin section of a semiconductor device and the support for the substrate. CONSTITUTION:A heat-cured resin is caused to melt to be equipped with a prescribed viscosity and is accommodated in a container 10. A semiconductor device 1, provided with a semiconductor pellet 2 of the prescribed performance, a substrate support 3 mounted with the semiconductor pellet 2, an electrode lead 4 electrically connected to the semiconductor pellet 2, and a resin section 5 accomplishing resin-sealing with one surface of the substrate support 3 remaining exposed, is dipped in a solution 11 and is pulled out of the solution 11 at a prescribed rate. Thereafter, the resin is hardened for the formation of a resin thin film 6 covering the resin section 5 and the substrate support 3. The thickness of the resin film is dependent upon the solution viscosity, the rate of pulling up, and the conditions whereunder the hardening process is accomplished. By using this method, a resin thin film may be formed not thicker than several tens of micrometers.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a resin-sealed semiconductor device, and particularly relates to a resin-sealed semiconductor device for large and medium-sized power sources that generate heat.

(b) Conventional technology In general, resin-sealed semiconductor devices are superior to metal-sealed semiconductor devices in terms of product cost, processability, mass production, etc.
However, it is inferior in terms of heat dissipation. However, in recent years, resin-sealed semiconductor devices for large and medium-sized power sources with good heat dissipation properties have been devised.

For example, as shown in FIG. 2, in order to improve heat dissipation, the substrate support is directly exposed and connected to a heat dissipation plate through an insulating spacer (1) such as a thin mica plate.

However, it has the disadvantage that it is complicated to install and is prone to accidents such as short circuits.

In order to avoid the shortcomings of the first half, JP 57-147260
As shown in the publication (Figure 3), when the substrate is clamped in the mold, it is clamped so that a certain gap is created at the bottom of the substrate support (to),
A thin layer of resin was provided on the underside of the substrate support.

(c) Problems to be solved by the invention In the structure as described above, the resin (E) (X) provided under the substrate support (E) (X) is formed thin in order to improve heat dissipation. In addition, to ensure good insulation, the film must not have pinholes or the like. Furthermore, in order to eliminate variations in heat dissipation characteristics, the resin portion must be formed uniformly. Therefore, there is a limit to the method using gold in obtaining a membrane structure with such characteristics.

Means for Solving the Problems The present invention has been made in view of these drawbacks, and includes a thin resin film (
6) can be solved by forming it by a dipping method.

(e) Working resin is dissolved to a predetermined viscosity with an organic solvent or the like, and a thin resin film (6) is formed around at least the resin portion (5) and the substrate support (3) by dipping as shown in FIG. form. The thickness of the resin thin film (6) can be controlled by controlling the viscosity of the solution, the speed at which the semiconductor device (1) is lifted out of the solution during immersion, the curing conditions, etc.

(F) Example An example of the present invention will be described below with reference to FIGS. 1 and 4.

Semiconductor pellet (2) with a predetermined function as shown in Figure 1
, a substrate support (3) on which the semiconductor pellet (2) is mounted, an electrode lead (4) electrically connected to the semiconductor pellet (2), such as a gold wire or aluminum wire, and the substrate support. One surface of the body (3) is exposed and a thin resin film (6) is formed around at least the resin part (5) and the substrate support (3) by a dipping method.

The feature of the present invention lies in the resin thin film (6) formed by the above-mentioned dipping method. Here, in the dipping method, it is necessary to use a thermosetting resin with good properties such as moisture resistance and insulation. This resin is dissolved with an organic solvent or the like to set a predetermined viscosity, and the resin is placed in a predetermined container as shown in FIG. 4, for example. Then, the semiconductor device (1) is immersed in the solution (6) and pulled up at a predetermined speed. The resin is then cured by UV irradiation and heat treatment. Here, the film thickness of the resin can be determined by considering the viscosity, pulling speed, curing conditions, etc.

(G) Effects of the Invention As mentioned above, the present invention provides at least the resin portion (
5) and the resin thin film (6) around the substrate support (3).
By forming the resin film, the thickness of the resin film was limited to several hundred μm when made of gold, but with the present invention, it is possible to form the resin film to a thickness of several tens of μm or less.

Further, since the resin (6) is shaped to cover the entire surface, it is possible to prevent moisture from entering, for example, the interface between the substrate support (3) and the resin portion (5).

Furthermore, there is no need to mount an insulating plate such as a mica plate, making it possible to reduce costs and simplify mounting.

Furthermore, since the resin (6) thick film can be made thinner, heat dissipation can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor device which is an embodiment of the present invention.
Figures 2 and 3 are cross-sectional views of conventional semiconductor devices;
The figure is a schematic diagram when the semiconductor device of the present invention is immersed. Explanation of main figure numbers (1) is semiconductor device, (2) is semiconductor pellet, (
3) is a substrate support, (4) is an electrode lead, (5) is a resin, and (6) is a resin thin film. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A semiconductor pellet, a substrate support on which the semiconductor pellet is mounted, an electrode lead electrically connected to the semiconductor pellet, and a resin part sealed with resin so that one surface of the substrate support is exposed. 1. A semiconductor device comprising: a thin resin film formed at least around the resin portion and the substrate support by a dipping method.