JPS6366953A - Polymer planar-metallization type semiconductor device and manufacture threrof - Google Patents

Abstract

PURPOSE:To improve the adhesive strength of a metallic frame and a molding resin, and to enhance heat-dissipating characteristics by forming irregularities on the radiating surface of the metallic frame while executing blast treatment. CONSTITUTION:In a semiconductor device having a shape that the radiating surface (the rear) of a metallic frame 1 on which a semiconductor chip 2 is mounted is electrically insulated by a resin 3, irregularities are formed to the radiating surface M of the metallic frame 1 while blast treatment is executed. The radiating surface M of the metallic frame 1 for a discrete power element is stamping-worked (irregularly-worked) on one surface in size of the square of 0.1mm depth and 0.5mm width, and roughened-surface working is executed to the surface of the radiating surface M through blast treatment. In this case, the working shape of irregularities may take a V shape, or a plane shape may take a striped, polygonal, circular or rectangular shape, etc.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a resin-insulated semiconductor device and a method for manufacturing the same, and is particularly used for improving the insulation characteristics and heat dissipation characteristics of large-sized devices. It is something that

(Prior Art) A schematic diagram of an insulated power transistor is shown in FIG. 4, for example. 1A is a plan view of the configuration, and FIG. 1B is a cross-sectional view of the same configuration, in which 1 is a metal frame, 2 is a chip, 3 is a resin, and 4 is a bonding wire.

Although not shown here, a plurality of frames 1 are normally arranged in a row in a row, and after being sealed with resin, the connecting portions are cut to form the shape as shown in FIG.

In the above-mentioned device, the transistor chip is usually fixed and the frame component, which is wired with thin wires such as Au or At, is sealed with a resin by transfer molding. This method is characterized in that the back surface (heat dissipation surface) of the frame 1 is also molded to be wrapped at the same time.

That is, this method is determined by the resin thickness and its thermal conductivity, and the resin material is λ = 40-60X10, which is called a high thermal conductive resin.
-'cal/crn-s/'c resin, for example, KE550T manufactured by Toshiba Chemical Co., Ltd., is used with a resin thickness t of about 0.5 to 0.6 cm. This method is highly suitable for mass production, and its thermal characteristics and dielectric strength characteristics have reached a practical level comparable to that of external insulation sheets (e.g., mica, mylar, etc.), and are mainly used in discrete power devices. It is used. In addition, in the manufacture of a composite element frame with separate frames, for example, as shown in FIG. 6, a structure in which heat dissipation fins 5 are added as shown in FIG. 5 is adopted especially from the viewpoint of structural strength.

(Problems to be solved by the invention) In these structures, cracks occur in the product due to the difference in thermal expansion coefficient (α) between the metal frame and the molded resin or metal plate, the molding shrinkage rate of the resin, etc. However, the external dimensions can be corrected sufficiently for practical purposes by bending the metal frame or metal plate in the opposite direction in advance. However,
Strain still remains between the metal and the resin, and if we try to develop a large-scale device with improved heat dissipation characteristics than ever before, the resin layer on the heat dissipation surface (back side) of the frame must be made even thinner, so this will increase. The strain increases, causing problems such as cracking or peeling of the resin layer.

The present invention has been made in view of the above circumstances, and is intended to increase the adhesive strength of the insulating resin layer of an insulated semiconductor device and improve the heat dissipation characteristics.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a semiconductor device in which the heat dissipation surface (back surface) of a metal frame is electrically insulated with a resin, in which unevenness is formed on the heat dissipation surface of the metal frame. By adding a rough surface to the metal frame and roughening it by blasting, the adhesive strength between the metal frame and the molded resin is improved, and as a result, the heat dissipation characteristics are improved.

(Example) An example of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view of the same embodiment. The concept is the same for element-separated devices such as composite devices, so to make the explanation easier to understand, we will use discrete devices as an example. In addition, parts corresponding to the conventional ones are given the same symbols and explanations are omitted.
I will explain the features. Here, the heat dissipation surface M of the metal frame 1 has dimensions of, for example, 0.1 m in depth and 0.5 m in width, and is engraved (irregularly processed) on one side, and furthermore, although it is not clear in the figure, the surface is blasted. It is characterized by a rough surface finish. Here, the processed shape of the unevenness may be V-shaped, and the planar shape may be striped, polygonal, circular, or rectangular, and the purpose is to increase the surface area.

Regarding the manufacturing method, it is also possible to adopt a so-called double molding method in which resin sealing is performed in two steps, which increases the number of manufacturing steps, but makes it easier to control the thickness of the insulating resin layer on the heat dissipation surface M side. , it is possible to manufacture products with a thin resin layer. When using such a manufacturing method, blasting is performed after the first resin sealing (molding of the upper side of the frame) and before the second resin sealing to prevent thin flakes and separation in the first resin seal. It is effective because mold oil can be removed at the same time.

FIG. 2 shows a modification of the present invention, in which metal radiation fins 5 are added, and the metal radiation fins may also be processed based on the same idea.

Figure 3 shows the results of a trial production using a frame with a heat dissipation area of 100s112. Here, the engraving shape is 0.1cm deep and 0.3cm wide.
0 - Mosaic, blasting media is made of rasp beads (
The processing conditions were a particle size of approximately 80 μm and a pressure of 5 kg 7 cm2. In Figure 3, A: no processing, B: blasting only, C: stamping only, D: stamping and blasting (invention), and the resin peeling strength (A) when A is set to "1". ,
This is comparative data of thermal resistance Rth (b). In terms of resin peel strength, A') compared to the non-marinated one, D, that is, the strength of the present invention is 5 to 8 times higher, and in comparison of thermal resistance Rth,
Approximately half the value was observed.

In addition, complete resin peeling phenomenon was observed in A and B, and there was some complete resin peeling in C, but about half of A and H (gap ~ 1
There was peeling of 0 μm).

This improvement in the heat dissipation characteristics of semiconductor devices is thought to be due to the fact that the increase in the thickness of the resin layer on the heat dissipation surface due to the uneven processing was kept to a minimum while maintaining negative characteristics, and the adhesive strength between the metal frame and the resin was increased. .

[Effects of the Invention] As explained above, according to the present invention, an insulated semiconductor device can be produced. ! , the adhesive strength of the edge resin layer can be increased and the heat dissipation properties can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view of another embodiment of the present invention, FIG. 3 is a characteristic diagram showing the effects of the embodiment of the present invention, and FIGS. FIG. 5 is a block diagram of a conventional resin-insulated semiconductor device, and FIG. 6 is a block diagram of a composite element frame. l...metal frame, 2...chip, 3...resin, 4...? 5...metal heat dissipation fin. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 BCO Figure 3 (a) (b) 4th Ward 5th Ward o OO 6th cause

Claims (2)

[Claims] (1) A semiconductor device in which the heat dissipation surface (back surface) of a metal frame on which a semiconductor chip is mounted is electrically insulated with resin, in which unevenness is provided on the heat dissipation surface of the metal frame and a blasting process is performed. A resin insulated semiconductor device characterized by: (2) In a method for manufacturing a semiconductor device in which the heat dissipation surface (back surface) of a metal frame on which a semiconductor chip is mounted is electrically insulated with resin, the resin molding is performed on the first
A resin-insulated semiconductor characterized in that, when resin molding and second resin molding on the heat radiating surface (back surface) of the metal frame are performed separately, a blasting process is performed after forming irregularities on the heat radiating surface and completing the first resin molding. Method of manufacturing the device.