JPS6248385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin-sealed semiconductor device, and more particularly to a resin-sealed semiconductor device having a container with an improved structure.

FIG. 1 shows a resin-sealed thyristor as a conventional example of a resin-sealed semiconductor device to which the present invention can be applied.

In FIG. 1, a semiconductor chip 1 having at least one pn junction is bonded to an anode electrode 2, a cathode electrode 3, and a gate electrode 4 via a brazing material (not shown), and each lead is connected to an anode lead 5, a cathode lead, and a cathode lead. 6. It is bonded to the gate lead 7 via a brazing material (not shown). The anode lead 5, cathode lead 6, and gate lead 7 are brazed to an insulating plate 9 made of Al ₂ O ₃ or the like having high thermal conductivity via a copper plate 8, and the insulating plate 9 prevents heat loss that occurs when electricity is applied. It is bonded via a brazing material 11 to a metal substrate 10 with excellent thermal conductivity for heat dissipation. Furthermore, a case 12 that covers the integrally brazed semiconductor chip, etc. is fitted into the annular groove 10a provided on the metal substrate 10, and is adhered with an adhesive 13 such as cyanoacrylate. The inside of the case 12 is molded with a resin 14 such as epoxy resin for mechanical protection.

FIG. 2 is an enlarged view of the portion indicated by A in FIG. 1.

In Fig. 2, the metal substrate 10 has a thickness of several mm to obtain mechanical strength, and there is a large difference in thermal expansion coefficient between the insulating plate 9 made of ceramic or the like and the metal substrate 10, ensuring thermal fatigue resistance. In order to do this, it is necessary to increase the thickness of the brazing filler metal 11. When the brazing material 11 is thickened, the brazing material 11a protrudes from the end of the insulating plate 9, and the protruding brazing material 11a enters the annular groove 10a provided for adhering the case 12, causing the case 12 and the metal to be bonded together. This has caused problems in engagement and adhesion with the substrate 10, and the intrusion of moisture from the outside has been a problem.

At the same time, the adhesive 13 used for engagement and adhesion between the case 12 and the metal substrate 10 may penetrate into the inside of the case 12 and impregnate the insulating plate 9, degrading the dielectric strength. .

An object of the present invention is to eliminate the above-mentioned drawbacks, and even when a brazing material for bonding an insulating plate to a metal substrate flows into the annular groove of the metal substrate, there is no problem in the engagement and adhesion of the case and the metal substrate. without causing
Prevents the adhesive used when bonding the case and metal substrate from penetrating inside the case.
An object of the present invention is to provide a resin-sealed semiconductor device having excellent moisture resistance.

The resin-sealed semiconductor device of the present invention that achieves the above object is characterized by: a metal substrate having an annular groove on one main surface; and a metal substrate surrounded by the annular groove on one main surface of the metal substrate. an insulating plate bonded via a brazing material on the part; and at least one
A semiconductor chip having a p-n junction and fixed to the insulating plate, a case whose cross section has approximately the same shape as the annular groove and which is engaged and bonded to the annular groove at one end, and the metal substrate and the case. a resin filled in a container formed by the semiconductor chip to at least cover the semiconductor chip, and a lead electrically connected to the semiconductor chip and protruding from the resin, A stepped portion is formed on the outer periphery of one end of the case to be engaged and bonded to the outer periphery of the opening of the annular groove, and the annular groove is connected to the one end of the case and the bottom surface of the annular groove in a state where the case is engaged and bonded. and the inner peripheral surface so as to have a gap therebetween.

In the present invention, the annular groove provided on one main surface of the metal substrate is not limited to an annular shape, but may be rectangular, a combination of annular and rectangular shapes, or endless. It can be anything you like.

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

FIG. 3 is an enlarged view of a portion corresponding to the portion A in FIG. 1 of a resin-sealed semiconductor device according to an embodiment of the present invention. In FIG. 3, a metal substrate 10
Except for the relationship between the upper annular groove 10a and the stepped portion 12a provided on the outer peripheral side of one end of the case 12, the structure is similar to that of the conventional type shown in FIG. 1 described above.

In the figure, with the case 12 engaged,
A gap is provided between one end of the case 12 and the bottom and inner circumferential surfaces of the annular groove 10a to allow the solder 11 to flow therein. The case 12 and the metal substrate 10 are bonded with a highly permeable adhesive 1 such as dianoacrylate.
3.

According to this embodiment, a brazing material 1 such as solder used to bond an insulating plate 9 to a metal substrate 10
1 flows into the annular groove 10a on the metal substrate, the brazing filler metal 11 flows into the gap between one end of the case 12 and the bottom and inner peripheral surface of the annular groove 10a.
There is no problem when the metal substrate 10 and the case 12 are engaged and bonded together.

Further, since the above-mentioned gap is provided, the adhesive 13 does not penetrate into the inside of the case 12.

The present inventors have found that when using a dianoacrylate adhesive, the adhesive 13 can be easily It was confirmed that there was no penetration into the interior of the case 12 due to capillary action.

Other embodiments of the present invention are shown in FIGS. 4 to 7.

The metal substrate 10 does not need to be on the same plane inside and outside the annular groove 10a, and there may be a step difference as shown in FIGS. 4 and 5.

Further, as shown in FIGS. 6 and 7, the annular groove 10a
The side surface of the metal substrate 10 does not need to be perpendicular to the main surface of the metal substrate 10 and may have an appropriate inclination, and furthermore, the bonding surface between the metal substrate 10 and the case 12 may be only one surface as shown in FIG. .

Furthermore, although the above description has been made using a thyristor as an example, the present invention is not limited to this, and can also be applied to resin-sealed semiconductor devices such as diodes and transistors.

As described above, according to the present invention, the annular groove of the metal substrate is formed so that there is a gap between one end of the case and the bottom and inner peripheral surface of the annular groove when the case is engaged and bonded. Even when the brazing material for bonding the insulating plate to the metal substrate flows into the annular groove of the metal substrate, there is no problem in the engagement and adhesion between the case and the metal substrate, and the engagement between the case and the metal substrate is maintained. It is possible to obtain a resin-sealed semiconductor device that has excellent moisture resistance and prevents the adhesive used in bonding from penetrating into the inside of the case.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional resin-sealed semiconductor device, FIG. 2 is an enlarged sectional view of the portion indicated by A in FIG. 1, and FIG. 3 is a resin-sealed semiconductor device according to an embodiment of the present invention. FIGS. 4 to 7 are enlarged cross-sectional views of a portion corresponding to the portion A in FIG. 1 of the sealed semiconductor device, and FIGS. It is an enlarged sectional view of a part corresponding to the part shown in A. DESCRIPTION OF SYMBOLS 1... Semiconductor chip, 2... Anode electrode, 3... Cathode electrode, 4... Gate electrode, 5... Anode lead, 6... Cathode lead, 7... Gate lead, 8
...Copper plate, 9...Insulating plate, 10...Metal substrate, 11...Brazing material, 12...Case, 13...Adhesive, 14...Resin.

Claims (1)

[Claims] 1 a metal substrate having an annular groove on one main surface;
an insulating plate bonded via a brazing material onto a portion of one main surface of the metal substrate surrounded by the annular groove; and a semiconductor chip having at least one pn junction and fixed to the insulating plate. a case having a cross section substantially the same shape as the annular groove and having one end engaged and bonded to the annular groove, and at least the semiconductor chip being covered within a container formed by the metal substrate and the case; and a lead electrically connected to the semiconductor chip and protruding outward from the resin, the opening outer periphery of the annular groove being located on the outer periphery side of one end of the case. forming a stepped portion that engages and adheres to the side;
The resin-sealed semiconductor device is characterized in that the annular groove is formed so as to have a gap between one end of the case and a bottom surface and an inner circumferential surface of the annular groove when the case is engaged and bonded.