JP2874431B2 - Resin-sealed semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device for a power diode module or the like applied to a rectifier circuit.

[0002]

2. Description of the Related Art Taking the diode module mentioned above as an example,
2. Description of the Related Art An assembly structure of a resin-sealed semiconductor device as shown in FIGS. In each figure, 1
Is a semiconductor chip, 2 is a metal base also serving as a heat sink on which the semiconductor chip 1 is mounted, 3 is an external lead terminal, 4 is an envelope combined with the metal base 2, and 5 is the inside of the envelope 4. It is a gel filler.

In the configuration shown in FIG. 2, the external lead-out terminal 3 is mounted on the metal base 2 via an insulator 6 at a position distant from the semiconductor chip 1, and a bonding wire 7 is provided between the external lead-out terminal 3 and the semiconductor chip 2. And the inside of the envelope 4 is filled with a gel-like filler 5 such as silicone, for example, to seal the semiconductor chip 1, external lead-out terminals 3, bonding wires 7, and the like. On the other hand, in the configuration of FIG. 3, the joining end 3 a of the external lead-out terminal 3 bent into an L shape is directly joined to the upper surface of the semiconductor chip 1 by soldering or the like, and the inside of the envelope 4 is not shown. As in the case of 2, the semiconductor chip 1 and the external lead-out terminal 3 are filled with a gel filler 5 and resin-sealed.

[0004]

When the above-described diode module is applied to a rectifier circuit, a smoothing capacitor is generally connected to the DC output side of the diode module. For this reason, when the power supply of the rectifier circuit is turned on, a large inrush current flows to the semiconductor chip through the smoothing capacitor, thereby generating heat. For this reason, the semiconductor chip has not only the required amount of resistance to the inrush current but also the heat dissipation property enough to withstand the heat cycle due to the repetition of the inrush current, even in the assembly structure of the semiconductor device. , It is required to secure the bonding strength.

Considering the conventional structure shown in FIGS. 2 and 3 from this point of view, in the structure shown in FIG. 2, most of the heat generated in the semiconductor chip 1 is transferred only to the metal base 2 and radiated to the outside, so that the heat radiation effect is reduced. Low. Further, in the structure of FIG.
However, since the external lead-out terminal 3 itself is formed of a thin metal plate, the heat-radiating effect through the external lead-out terminal 3 can hardly be expected in practice.

Further, the semiconductor chip 1 and the external lead terminals 3
The solder joints and wire bonding parts between
When a heat cycle accompanying the repetition of the rush current is applied, the bonding strength gradually decreases, and the bonded portion is easily peeled. Moreover, the soft gel-like filler 5 filled inside the envelope 4 as a sealing resin as in the conventional structure shown in FIGS. 2 and 3 does not function to reinforce the joint, so that the heat When the deterioration of the bonding portion progresses due to the cycle, the bonding wire and the external lead-out terminal are easily peeled off from the semiconductor chip, resulting in an open breakdown.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a resin-encapsulated semiconductor device capable of solving the above-mentioned problems and improving heat dissipation and durability against heat cycles. Is to do.

[0008]

Among the above objects, a first object of improving heat radiation is to make the joining end of an external lead terminal surface-joined to a semiconductor chip according to the present invention thicker than other lead portions. This is achieved by forming the structure to have a large thickness. A second object of improving the durability is to fill the inside of the envelope with a hard resin according to the present invention and to harden the resin to form a semiconductor chip,
This is achieved by sealing the external lead-out terminal with resin. Preferably, an epoxy resin is used as the hard resin.

[0009]

In the above structure, the joining end of the external lead terminal which is surface-joined to the semiconductor chip is formed to be thicker than the other leads, so that the joining end is effective as a heat absorber for heat generated by the semiconductor chip. In particular, the transient heat generated due to the inrush current can be absorbed by the heat capacity of the junction end of the external lead-out terminal, and the heat dissipation of the semiconductor chip is improved.

On the other hand, the inside of the envelope is filled with a hard resin such as an epoxy resin and cured to seal the semiconductor chip and the external lead-out terminal with a resin, thereby sealing the joint between the semiconductor chip and the external lead-out terminal. Since it is firmly fixed from the surroundings by the resin, a joining structure having high durability against heat cycles can be obtained.

[0011]

FIG. 1 shows an embodiment of the present invention. In the figure, the same members corresponding to FIG. 3 are denoted by the same reference numerals. That is, the external lead-out terminal 3 bent into an L-shape to be joined to the upper surface of the semiconductor chip 1 in FIG. 1 has a lead portion 3b in which the thickness d of the joint end 3a at the tip thereof rises in advance from the joint end. The bonding end 3a is surface-bonded to the upper surface of the semiconductor chip 1 by soldering or the like. In addition, the inside of the envelope 4 is filled with a hard resin 8 such as an epoxy resin as a sealing resin and cured to seal the semiconductor chip 1 and the external lead-out terminals 3 with a resin. It is firmly fixed from the surroundings.

[0012]

As described above, according to the structure of the present invention, the junction end of the external lead-out terminal functions as a heat absorber, so that the heat dissipation to the semiconductor chip can be improved. In addition, by using a hard resin such as an epoxy resin as the sealing resin, the sealing resin firmly fixes a joint portion between the semiconductor chip and the external lead terminal from the periphery,
It is possible to prevent peeling of the joint portion caused by a heat cycle due to repetition of an inrush current or the like, thereby improving durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a configuration of a conventional resin-encapsulated semiconductor device.

FIG. 3 is a cross-sectional view of a configuration of a conventional resin-encapsulated semiconductor device different from FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Metal base 3 External lead-out terminal 3a Tip leg 3b Lead part 4 Enclosure 8 Hard resin (epoxy resin)

Claims (3)

(57) [Claims] 1. A resin-sealed semiconductor device in which an external lead-out terminal is joined to an upper surface of a semiconductor chip mounted on a metal base, and a sealing resin is filled inside an envelope combined with the metal base. 3. The resin-encapsulated semiconductor device according to claim 1, wherein the joining end of the external lead terminal which is surface-joined to the semiconductor chip is formed thicker than other lead portions. 2. The resin-encapsulated semiconductor device according to claim 1, wherein the inside of the envelope is filled with a hard resin and cured to seal the semiconductor chip and the external lead-out terminals. Resin-sealed semiconductor device. 3. The resin-sealed semiconductor device according to claim 2, wherein the hard resin is an epoxy resin.