JPS5840848A - Insulating type semiconductor device - Google Patents

Abstract

PURPOSE:To improve the reliability of an insulating type semiconductor device, providing projections approximately parallel with the main surface of a substrate in a groove of a case adhesion part provided on a metallic substrate. CONSTITUTION:A projection 17 is provided in a groove 16 of a metallic substrate 2. In such a constitution, cracks do not generate on the end part of an insulating plate 4 resulting in the prevention of the thermal fatigue of a solder 3. Therefore, the reliability of insulating withstand voltage and thermal fatigue withstand strength increases. Further, since a resin 13 on injection flows in the lower side of the projection 17, and the creepage distance to a chip 10 is long, out air interruption improves resulting in the imcrease of resisting force against tensile force from the outside. The metallic substrate 2 is pressed by a male mold 17a, a projection 18b is formed simultaneously with a mount hole 19 and the groove 16, and further the projection 18b is deformed by pressing by a male mold 17b, and thus the projection can be easily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Misfire 1jll relates to the structure of a metal substrate in an insulated semiconductor device.

Generally, an insulated semiconductor device includes a semiconductor chip and q! for energizing the semiconductor chip. R type terminal, a metal substrate for transmitting the heat loss generated in the semiconductor chip when energized to the external heat dissipation fin, and supporting the semi-integrated chip, and electrically connecting the metal substrate, the semiconductor chip, and each yuzu xiω. At t Os with high thermal conductivity to insulate
The insulating plates such as the above are integrated by brazing, etc., and a case that houses the integrally brazed semiconductor chips etc. is glued around the metal substrate, and electrical and mechanical parts are protected from the external atmosphere. The case is manufactured through a process in which the inside of the case is filled with resin such as epoxy resin for protection. This will be explained below using the drawings.

FIG. 1 shows an example of a conventional insulated semiconductor device.

In FIG. 1, inner leads 8.9 are brazed to two surfaces of the semiconductor chip 10 using brazing materials ita and iib, and the inner leads 8 and 9 are further connected to the cathode electrode 6c and It is connected to the gate I electrode 6b. The lower surface of the semi-integrated chip 10 is connected via the brazing material 7a,
It is bonded to the anode electrode 6a. Further, the cathode electrode 6c, anode electrode 5a, and gate electrode 61) are made of a brazing material 5c.

The insulating plate 4 is bonded to the metal substrate 2 via the brazing material 3 via the insulating plate 4 made of ceramic or the like.
is glued to. Note that the brazing portion of the insulating plate 4 is metallized.

The case 12 is bonded to the groove 16 on the metal substrate 2 with an adhesive, and the inside of the case is filled with resin 13.

In such a conventional one-layer structure, there is a large difference in linear expansion coefficient between the resin 13 and the metal substrate 2, so if heat cycles or the like are applied from the outside, the resin 13 may peel off between the metal substrate 2. This makes it easier for moisture, etc. to enter from the outside, and the barrier properties deteriorate. Therefore, there is an overhang 1 on the insulating plate 4.
5 and inserting the resin 13 therein may be considered to ensure the barrier property. The overhang portion 15 protrudes further to the periphery than the soldering hole 3, and therefore has a larger creepage length, so that the above-mentioned effect can be expected.

However, if this is done, the difference in linear expansion coefficient between the register 13 and the insulating plate 4 is even larger than that with the metal substrate, so cracks are likely to occur on the end face of the insulating plate due to thermal stress due to external heat cycles. There is a risk of deteriorating the withstand voltage. Furthermore, the brazing material 3 between the insulating plate 4 and the metal substrate 2 is
There was a risk that cracks and peeling would occur due to the insulating plate 4 being chipped upward due to thermal expansion of the resin directly under the over-knob portion I5. As described above, the conventional example has the disadvantage of extremely low reliability in terms of dielectric strength, thermal fatigue resistance, and isolation from the outside air.

The purpose of the present invention is to improve the drawbacks of the conventional example, and to improve the dielectric strength and
An object of the present invention is to provide an insulated semiconductor device with good thermal fatigue resistance and external air insulation.

A feature of the present invention is that, in an insulated semiconductor device, a protrusion that is substantially parallel to the main surface of the metal substrate is provided inside the case bonding portion 11f formed on the metal substrate.

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

FIG. 2 is a sectional view of a main part of an embodiment of the present invention.

The parts other than those shown in Figure 2 are the same as in Figure 1, so
Illustrations are omitted. The overhang portion of the insulating plate 4 has been removed and a protrusion 17 is provided inside the groove 16 of the metal substrate 2 instead! There is a time.

This eliminates the occurrence of cracking sounds at the ends of the insulating plate 4, and also prevents thermal fatigue of the brazing filler metal 3. As a result, the reliability of dielectric strength and thermal fatigue resistance can be improved. Furthermore, the resin 13 is applied to the bottom 1 of the protrusion 17 of the groove during injection.
116, and the creepage distance from the outside air to the semiconductor chip 10 can be increased, so that the insulation against outside air can also be improved. It is said that the time required for outside air to penetrate the gap between the resin and other members is proportional to the fourth power of the creepage distance. Furthermore, the protrusion 17 increases the resistance against external tensile force applied to the electrodes and the like.

The metal substrates of the two series of embodiments can be easily manufactured by press working. FIGS. 3 and 4 show an embodiment of the manufacturing process for the metal substrate 2 having protrusions.

FIG. 3 shows the first male press 417a having been pressed onto the metal dove board 2. Through press working, screw holes 19 for fixing the metal substrate 2 to an external support material and 4 of the metal substrate are formed.
At the same time as the mold 16 is formed, a protrusion 18I) is formed along the stub 18a of the male press mold 17a. Furthermore, as shown in FIG. 5, when the second press male die 17b is pressed against the metal substrate 2, the protrusion 18b is deformed and a scrap protrusion 17 is formed.

FIG. 5, FIG. 6, and FIG. 7 show main parts of other embodiments of the present invention. A feature of the embodiment shown in FIG. 5 is that the groove 16 has a trapezoidal cross section. In this way, even if the cross-sectional shape of the metal substrate is trapezoidal, there is no problem at all.

As shown in Figure 6, the resin 13 is
Even if the device is manufactured by injection or transfer molding, there will be no change in characteristics.

FIG. 7 shows an example of application of FIG. In FIG. 7, the protrusion 17 is located near the outer periphery of the chimney 16.

In this way, the protrusion of the groove can be located anywhere inside the load. In addition, the protrusion of % iFj is β
However, even if it is only part of the debris, there is no problem at all.

Although the above embodiments have been described with reference to individual semiconductor devices, the present invention can also be applied to hybrid ICs such as modules.

As detailed above, according to the present invention, an insulated semiconductor device having excellent dielectric strength, thermal fatigue resistance, and isolation from outside air can be easily provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a conventional insulated semiconductor device, FIG. 2 is a sectional view of an insulated semiconductor device according to an embodiment of the present invention, and FIGS. 3 and 4 are sectional views of an example of a conventional insulated semiconductor device. A cross-sectional view of the male bracelet and the metal substrate in the manufacturing process of the metal substrate used in the example,
FIG. 5, FIG. 6, and FIG. 7 are new views of one loaf of an insulated semiconductor device according to another embodiment of the present invention. 2... Metal substrate, 3... Brazing material, 4... Insulating plate,
12...1st figure half 2 figures

Claims (1)

[Claims] (2) At least one semiconductor chip electrically insulated from the metal substrate and an electrode lead electrically connected to the semiconductor chip are placed on a part of the surface of the metal substrate; In a structure in which the semiconductor chip and at least part of the electrode leads are coated with resin,
An insulated semiconductor device characterized by having a groove on the peripheral edge of the metal substrate and a protrusion inside the groove that protrudes from the groove.