JPS60242649A - Resin sealed semiconductor device - Google Patents

Abstract

PURPOSE:To prevent resin from shrinking or expanding due to the temperature cycling thereof and to improve the strength against peeling, by providing a groove having projections on the inner walls thereof, in the direction intersecting with the line connecting a semiconductor pellet and a tightening hole. CONSTITUTION:A semiconductor pellet 3' is attached to a first main face 1a of a heat-conductive plate 1. A part of the first main face 1a and a second main face 1b are exposed, and a resin sealing body 6' is formed on the heat-conductive plate 1 so as to cover the semiconductor pellet 3'. On the semiconductor pellet 3, V-shaped grooves 4 are provided so as to surround the joint portion of the semiconductor pellet so that the resin penetrates into these grooves, while holes 5 are also provided for preventing the resin from expanding or shrinking. A groove 7 which is provided between these holes 5 is oriented in the direction intersecting with the line connecting a tightening hole 2 and the joint portion 3 of the semiconductor pellet. According to such construction, the resin on the side A1 is prevented from moving toward the side A2 due to thermal shrinkage thereof after sealing the device with the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a resin-sealed semiconductor device, particularly to a resin-sealed semiconductor device for output.

[Background Art] Resin-sealed semiconductor devices are mounted by sealing with resin after electrical connection between the electrodes of a semiconductor pellet connected to a substrate and external leads is completed, and it is used as an output semiconductor integrated circuit. In the case of a device, from the viewpoint of heat dissipation and improvement of moisture resistance, a heat dissipation plate as shown in FIGS. 1(a) to (c), for example, was considered as a substrate. Figure 1 (,) is a plan view of the heat sink, and Figure 1 (b) is At A2 in Figure 1 (,).
A cross-sectional view and FIG. 1(e) is B in FIG. 1(,).
-B is a sectional view. First, in Figure 1 (,), 1
2 is a thermally conductive plate material forming a heat dissipation plate, 2 is a hole for passing a tightening bolt, 3 is a semiconductor pellet connection part, and 4 is a resin biting part, which is used to cut the resin in the lateral direction near the semiconductor pellet connection part. Provided to prevent movement. The reason for providing the V-groove is that without it, the resin would not have any hooks to resist lateral movement, and the resin would expand and contract due to thermal cycles, making it easier for shear stress to be applied to the pellet. be. It is also provided to lengthen the path for water to enter the interface between the plate material and the resin. And 5 is a hole for more effectively preventing expansion and contraction of the resin due to thermal cycles. In FIG. 1(b), a region 6 surrounded by a broken line is a hole which is sealed with resin so as to cover the semiconductor pellet 3'.

In a resin-sealed semiconductor device using such a heat sink, the distance between the resin sealing part and the tightening hole is narrow, and as a result, the gap between the resin and the heat sink is likely to separate when tightened with bolts. , the problem is that gaps are likely to form, leading to a decrease in moisture resistance, and the resin expands and contracts more easily due to temperature cycles, which increases the shear stress applied to the pellet, causing cracks in the pellet and wire breakage. was there. In particular, on the A2 side, resin exists not only on the top surface of the heat sink but also on the side surfaces, and is strong against forces in the direction from A2 to A. The resin) is simply located on the heat dissipation plate and is extremely weak against the force in the direction from A to A2, and due to thermal cycles the semiconductor pellet will move from A1 to A2.
This is because the shearing stress directed toward 2 is applied. That is, since the expansion and contraction occurs not around the pellet part but around the A2 side surface, the shear stress that the pellet receives is unexpectedly strong. Also, Figure 1 (
As shown in a)=(c), the hole 5 has a straight structure, that is, it does not have a structure in which the resin is caught in the vertical direction, so the bolt tightening applied in the direction of the arrow is weak against the force W. Therefore, when the bolts are tightened, the resin and the heat dissipation plate are likely to separate, resulting in a gap. Therefore, the groove for biting in the resin could not be very effective in preventing the resin from moving in the lateral direction.

Note that the structure for restraining the resin surrounding the semiconductor pellet and the wire is disclosed in Japanese Patent Application Laid-open No. 52-1989! It is known from Publication No. 29379 (published on April 23, 1975).

However, in the resin-sealed semiconductor device disclosed in this publication, separation between the heat sink and the resin is likely to occur;
Insufficient moisture resistance.

The present invention has been achieved based on the recognition of the above problems.

[Objective of the Invention J] An object of the present invention is to provide a highly reliable resin-sealed semiconductor device with improved moisture resistance.

[Summary of the Invention] The present invention for achieving the above object is characterized by the following configuration.

A first main surface and a second main surface located on the opposite side to this main surface.
a thermally conductive plate material having a main surface; a semiconductor pellet attached to the first main surface; and a resin seal that covers the semiconductor pellet t so as to expose a portion of the first main surface and the second main surface. a groove provided adjacent to a portion of the first principal surface exposed in the resin-sealed body and having a projection on the inner wall; and a groove provided so as to surround the semiconductor pellet; A resin-sealed semiconductor device comprising: a groove shallower than the above-mentioned groove;

[Example] The present invention will be explained below using specific examples.

FIGS. 2(a) and 2(b) show a heat sink for a fat-sealed semiconductor device according to an embodiment of the present invention;
is a plan view, and Fig. 1(b) is A1- in Fig. 1(,).
A2 is a sectional view.

Reference numeral 1 denotes a thermally conductive plate material, which has a first main surface 1a and a second main surface 1b located on the opposite side to this main surface, as shown in FIG. 2(b). 2 is a tightening hole, 3 is a semiconductor pair pellet connection part, 4 is a resin groove formed to surround the semiconductor plate/node connection part (1 is included), 5 is a hole for preventing resin expansion and contraction, 6 is a part to be sealed with resin, 7 is a groove provided between the holes 5 for preventing resin expansion and contraction, and 8 is a protrusion provided on the inner wall of this groove.This groove 7 connects the tightening hole 2 and the semiconductor pellet. The hole 5 is oriented in a direction intersecting the line connecting the connecting portion 3, and is provided so as to span between the two holes 5.

FIG. 2(c) shows a cross-sectional view of a resin-sealed semiconductor device assembled using a heat sink having the above-mentioned configuration, and in particular, FIG.
It is a figure corresponding to the At A2 view cross section in a). As shown in FIG. 2(c), in the resin-sealed semiconductor device of the present invention, a semiconductor pellet 3' is attached to the first principal surface 1b of the thermally conductive plate 1. And the first main surface 1a
A resin encapsulant 6' is formed on the thermally conductive plate 1 so as to expose a portion of the semiconductor pellet 3' and the second main surface 1b and cover the semiconductor pellet 3'. In addition, in FIG. 2(c), the external lead and the wire electrically connecting the external lead and the electrode of the semiconductor pellet are omitted.

According to the present invention explained above, the object is achieved for the following reasons.

In FIG. 2(c), A after being sealed with resin,
The resin on the side is prevented from moving toward the A2 side due to thermal contraction. In other words, even if there is a slight gap between the resin and the heat sink at that part due to bolt tightening, the groove 7
This prevents the resin from moving toward the A2 side, and reduces the stress applied to the semiconductor pellet portion due to the expansion and contraction of the resin.

As a result, the occurrence of semiconductor pellet cracks or wire breakage is prevented. In particular, since the groove 7 has a protrusion 8 on its inner wall, it is extremely effective in preventing the resin from moving toward the A2 side.

The protrusions also function to increase the strength in the peeling direction F. Therefore, the purpose of the shallow V-groove 4 for biting into the resin, which is provided to prevent the resin from moving in the lateral direction near the semiconductor pellet, can be fully achieved. Therefore, the combination of a groove with an internal protrusion and a shallower V-groove surrounding the semiconductor pellet is extremely effective in improving moisture resistance.

The above-mentioned groove with a protrusion on the inner wall is illustrated in FIG. 3(a), for example.
As shown in (b), it can be formed in two press steps.

The first pressing process has a width d2 and a height t2 (the thickness of the heat sink is 1).
．． >12) using the first press upper mold 9-1.

In the second step, a width d2 (dl<d2) and a lower height t than the first press upper die used in the first press step are formed.
This is carried out using the second press upper die 9-2 of i (h < h).

As a result, the ridge 7a of the groove 7 formed in FIG.

In this way, processing to prevent resin peeling can be easily achieved by two-step press processing from the first main surface side of the heat sink.

Note that the reason why this groove is not made into a through hole is to prevent the heat dissipation from becoming low. However, it goes without saying that this groove may be in the form of a through hole if a somewhat lower heat dissipation is not a problem.

Furthermore, since it is sufficient that the protrusion 8 is formed on the inner wall of the groove on the A2 side (that is, the Benz F side), the protrusion 8 may be formed only on the inner wall on the A2 side as shown in FIG. good.

As described above, according to the present invention, since the groove with the protrusion is formed on the inner wall in the direction intersecting the line connecting the semiconductor pellet and the tightening hole, the expansion and contraction due to the temperature cycle of the resin is prevented, and peeling is prevented. Strength also increases.

[Brief explanation of drawings]

Figures 1 (a) to (e) show examples of heat sinks for resin-sealed semiconductor devices that were conceived prior to the present invention; (a)
is a plan view, (b) is a sectional view of A,-A2, and (c) is B-
It is a sectional view from B. FIG. 2(a) is a plan view of a heat sink for a resin-sealed semiconductor device according to an embodiment of the present invention;
b) is a sectional view of A, -A2 in Fig. 2(a), Fig. 2(c)
) is a sectional view of a resin-sealed semiconductor device assembled using the heat sink shown in FIG. 2(,). #3 Figures (a) and (b) are sectional views of essential parts showing the pressing process for obtaining the heat sink shown in Figure 2 (,), and Figure 4 is a cross-sectional view of another heat sink applied to the present invention. It is a sectional view showing an embodiment. 1. Thermal conductive plate material, 2. Tightening hole, 3. Semiconductor pellet connection part, 3°... Semiconductor pellet, 4. V groove for resin biting, 5. Hole for preventing resin expansion and contraction. 6...Position to be sealed with resin, 6゛...Resin sealing body, 7...Groove, 8...
Projection, 9-1.9-2 No. 1 Figure 4 (b)

Claims (1)

[Claims] A first main surface and a second main surface located on the opposite side to this main surface.
a thermally conductive plate material having a principal surface; a semiconductor pellet attached to the first principal surface; and a resin sealing body covering the semiconductor pellet so as to expose a portion of the first principal surface and the second principal surface. a groove provided in the resin molded body in close proximity to a portion of the exposed first principal surface and having a protrusion on the inner wall; and the groove provided so as to surround the semiconductor pellet. A resin-sealed semiconductor device having a groove shallower than that of the semiconductor device.