JPH036846A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To prevent lowering of humidity resistance effectively and to improve it greatly by forming a groove section having a sectional shape whose upper side width is narrower than its bottom side width. CONSTITUTION:A groove section 4 wherein resin part 3 is partially filled is formed in a specified position of a heat sink 2. The groove section 4 is formed in a sectional shape whose upper side width is narrower than its bottom side width. Since the resin part 3 which armor-seals a semiconductor chip is partially filled in the groove section, a junction distance between a heat sink along an inner periphery of the groove and a resin part is longer than a conventional one, thereby improving prevention function against penetration of humidity to the groove section.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to resin-encapsulated semiconductor devices (hereinafter referred to as semiconductor devices) such as power transistors and thyristors.
In particular, the present invention relates to a connection structure between a heat sink on which the semiconductor chip is mounted and a resin part in which the semiconductor chip is externally sealed.

[Conventional technology]

Conventionally, in this type of semiconductor device, a structure such as the TQ220 type power transistor,
That is, as shown in the partially cutaway side view in FIG. 3 and the external perspective view seen from the back side in FIG. A structure in which this semiconductor chip 1 is externally sealed with a resin part 3 made of epoxy resin is generally adopted. In this semiconductor device, a groove portion 4 filled with a portion of the resin portion 3 is formed in advance at a predetermined position on the heat dissipation plate 2 by stamping (pressing) or the like.
By connecting the heat dissipation plate 2 and the resin part 3 through a part of the resin part 3 filled in the groove part 4, the two are joined in a state in which they are in close contact with each other. The cross-sectional shape of the groove 4 is U-shaped or V-shaped, and the heat sink 2 and the resin part 3 are disposed along the inner surface of the groove 4.
As a result of extending the bonding distance between the two, it becomes difficult for moisture that has entered from the outside to reach the semiconductor chip l through the bonding interface between the two, and there is an advantage that the semiconductor device can have a certain degree of moisture resistance.

By the way, in the semiconductor device configured in this way, the heat generated in the semiconductor chip 1 when energized is transferred to the heat sink 2.
It has the advantage that a high current can be passed through the semiconductor chip l because it is dissipated to the outside through the semiconductor chip l.

[Problem to be solved by the invention]

However, depending on the groove portion 4 formed in the heat sink 2 constituting the semiconductor device with the conventional structure, there is a time period for the hot air that has entered from the bonding interface between the heat sink 2 and the resin portion 3 to reach the semiconductor chip 1. Although it is possible to delay its arrival, it is very difficult to prevent its arrival for a long time, and the durability of semiconductor devices is 1! It has become difficult to improve one's sexuality.

Furthermore, when this semiconductor device is attached to a printed wiring board (not shown) by soldering, far-infrared reflow, or a mounting method called paper phase, the heat generated by each of the heat sink 2 and the resin part 3 is Due to the difference in expansion coefficients, thermal stress acts in a direction that causes the heat sink 2 and the resin part 3 to be peeled off from each other, and as a result, the adhesion between the two deteriorates. 3 will come out, and the bonding interface between the heat sink 2 and the resin part 3 will open. Therefore, outside moisture will be absorbed through the gap formed between the heat sink 2 and the resin part 3. This would easily penetrate into the interior of the semiconductor device, resulting in a further decline in the moisture resistance of the semiconductor device.

This invention was devised in view of these inconveniences, and improves moisture resistance by improving the connection structure between the heat sink on which the semiconductor chip is mounted and the resin part in which the semiconductor chip is externally encapsulated. It is an object of the present invention to provide a semiconductor device that can effectively prevent the deterioration and significantly improve the deterioration.

[Means to solve the problem]

The present invention comprises a heat sink on which a semiconductor chip is mounted, and a resin part in which the semiconductor chip is externally sealed, and a groove part filled with a part of the resin part is provided at a predetermined position on the heat sink. The semiconductor device thus formed is characterized in that the cross-sectional shape of the groove portion is formed such that the width of the top surface thereof is narrower than the width of the bottom surface thereof.

[Effect]

According to the above configuration, since the #fr surface-shaped groove is formed in the heat sink, the width of the top surface is narrower than the width of the bottom surface,
The bonding distance between the heat sink and the resin part along the inner surface is longer than in the conventional example, which increases the function of preventing moisture from entering the groove. As a result, when this semiconductor device is mounted, thermal stress acts in a direction that causes the heat dissipation plate and the resin part to be peeled off from each other. Even if the bonding interface is opened, the adhesion between the two will not deteriorate and the bonding interface will not open.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partially cutaway side view showing the structure of a semiconductor device according to the present invention, and FIG. 2 is a sectional view showing an enlarged main part thereof. Note that the overall configuration of this semiconductor device is basically the same as the conventional example described above, except for the cross-sectional shape of the groove formed in the heat sink, so parts that are the same or equivalent to each other,
The same reference numerals are given to the parts, and detailed explanation thereof will be omitted here.

The semiconductor device according to this embodiment includes a heat sink 2 on which a semiconductor chip 1 is mounted, and a resin part 3 made of epoxy resin that externally encapsulates the semiconductor chip 1, and extends from the semiconductor chip 1 and the heat sink 2. The lead terminals 5 are connected to each other via internal lead wires 6. A groove 4 filled with a part of the resin part 3 is formed at a predetermined position on this radiation p'Fiz, and the cross-sectional shape of this groove 4 is as follows.
A shape where the top width is narrower than the bottom width, for example,
It is formed into a roughly trapezoidal shape that is called an ``arimizo''. Note that in order to form the groove 4 having such a cross-sectional shape, as shown in FIG. Similar U-shaped groove (indicated by reference numeral 4a in the figure)
In addition to forming the groove 4a, the upper outer edge of the groove 4a may be further bulged toward the inner side facing each other by a second stamping process. Another advantage is that the upper surface side portion of the material is work hardened, increasing its mechanical strength.

In the groove portion 4 having such a shape, the inner surface thereof is inclined so as to narrow from the bottom surface side to the upper surface side, so that the bonding between the heat dissipation plate 2 and the resin portion 3 along the inner surface is prevented. As the distance becomes longer, a part of the resin part 3 filled in the groove part 4 is firmly supported by the groove part 4 in a state where it cannot be removed.

〔Effect of the invention〕

As explained above, according to the semiconductor device of the present invention, a groove portion having a cross-sectional shape whose top width is narrower than its bottom width is formed at a predetermined position on a heat sink on which a semiconductor chip is mounted, and Since the groove is filled with a part of the resin part that externally encapsulates the semiconductor chip, the bonding distance between the heat sink and the resin part along the inner peripheral surface of the groove is longer than in the conventional example.
This increases the function of preventing hot air from entering the groove.

In addition, a part of the resin part filled in this groove is supported by the groove in a state that cannot be removed, so when this semiconductor device is mounted, thermal stress is applied in the direction of peeling off the heat sink and the resin part. Even if the bonding interface is opened, the adhesion between the two will not deteriorate and the bonding interface will not open. the result,
The excellent effect of effectively preventing a decrease in moisture resistance in a semiconductor device and significantly improving it can be obtained.

[Brief explanation of drawings]

1 and 2 relate to the present invention; FIG. 1 is a partially cutaway side view showing the configuration of a semiconductor device according to the present invention;
The figure is an enlarged sectional view of the main part. Also, the third
4 and 4 relate to a conventional example, FIG. 3 is a partially cutaway side view showing the configuration of a semiconductor device, and FIG. 4 is an external perspective view of the semiconductor device as seen from the back side. In the figure, reference numeral 1 is a semiconductor chip, 2 is a heat sink, 3 is a resin part, and 4 is a groove part. Note that the same reference numerals in the drawings indicate parts and portions that are the same or correspond to each other. Figure 1

Claims (1)

[Claims] (1) A heat dissipation plate mounted with a semiconductor chip and a resin part externally encapsulating the semiconductor chip, and a groove part filled with a part of the resin part is formed at a predetermined position on the heat dissipation plate. A resin-sealed semiconductor device comprising: a cross-sectional shape of the groove portion having a top width narrower than a bottom width thereof.