JPS63208253A - Semiconductor circuit device - Google Patents

Abstract

PURPOSE:To improve the yield rate in manufacturing, by providing a depletion part including a gap formed by the thermal deformation of a packaging case between the attaching and tightening part of the packaging case and heat radiating fins, and filling the depletion part and the gap with a resin through a narrow slit. CONSTITUTION:A depletion part 28, which is separated from an attaching hole 27, is provided in an attaching and tightening part 26 of a packaging case 23. The depletion part 28 is filled with a resin 24 through a resin injecting path 29, which is communicated to the inside of the case. The gap between the attaching and tightening part 26 of the packaging case 23 and heat radiating fins 21 is filled so as to withstand tightening pressure. Thus cracking of the packaging case 23 at the time of packaging is prevented. Since the resin injecting path 29 is made narrow, the pressure of the resin, which is inputted in the depletion part 28, is largely decreased in comparison with the pressure at the inlet port of the resin injecting path 29, i.e., the pressure of the resin at the inner wall of the case. Therefore the resin does not leak to the outside through the depletion part 28.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a circuit board (which also serves as a heat dissipation fin and an envelope bottom plate) on which circuit components made of semiconductor elements, etc. are mounted, and an envelope. This relates to a semiconductor circuit device that is fitted with a case and filled with resin and mainly requires heat dissipation, and the circuit is used when the heat dissipation fin (circuit board) of this semiconductor circuit device is attached to an external heat sink, etc. This relates to the structure of the device's mounting and tightening part, and is mainly used in power devices such as SSRs (solid state relays).

<Prior art> The envelope of a semiconductor circuit device used for electric power is generally made by fitting an envelope case to heat dissipation fins that also serve as the bottom plate of the envelope, and injecting epoxy resin etc. into the case. Many of them are in hardened form. Since such a circuit device is generally used by being attached to a support member such as an external heat radiator, a mounting and tightening portion is provided in the envelope. This mounting tightening part has two types: (a) the heat dissipation fin is covered with an envelope case, and (b)
It is said to consist only of heat dissipation fins that are not covered by a case. The semiconductor circuit device according to the present invention is related to the above item (A). FIGS. 4 and 5 are schematic cross-sectional views of such semiconductor circuit devices.

The radiation fin 1 serves as an envelope bottom plate and a circuit board, and has internal circuit components 2 and the like mounted thereon via an insulating film made of ceramic or the like. The envelope case 3 is fitted with the radiation fins 1, circuit components, external terminals 5, etc. are housed in the envelope case, and the epoxy resin 4 is injected and solidified. The enclosure case 3 is provided with a mounting fastening portion 6 shown by a dotted line, and the device is mounted to an external heat sink or the like with bolts or the like using a mounting hole 7.

The envelope of such a conventional semiconductor circuit device undergoes slight deformation in the envelope case 3 due to thermal processes during the manufacturing process, and in particular, the mounting and tightening portion 6 is slightly deformed, as shown in FIG. 5 or a partially enlarged view. As shown in FIG. 6, a gap is likely to be formed between the case 3 and the radiation fins 1. When using a case made of an organic material, deformation of the case is an unavoidable problem. If such a gap is created, when the semiconductor circuit device is attached to an external heat sink or the like, the envelope case often cracks because the screws are tightened.

(Problems to be Solved by the Invention) As mentioned above, in the case of a conventional semiconductor circuit device, the woofer is deformed due to heat processing, etc., and a gap is created between the case and the heat dissipation fin, which causes problems during installation. , the case tends to crack when the screws are tightened. This not only impairs the reliability of the circuit device, but also leads to destruction of the device in severe cases.

It is an object of the present invention to provide a semiconductor circuit device having a structure that eliminates the occurrence of cracks in the envelope case due to tightening when mounting the semiconductor circuit device, and prevents the filled resin from leaking to the outside. purpose.

[Structure 1 of the Invention (Means and Effects for Solving Problems) The present invention provides circuit components that are mounted on a circuit board that also serves as an envelope bottom plate and a heat dissipation fin, and that are fitted with an envelope case. In a semiconductor circuit device configured by filling resin inside the enclosure, a mounting hole is provided in the mounting tightening part of the envelope case, and a void space is isolated from the mounting hole. This is filled with resin to fill the gap between the mounting tightening part of the enclosure case and the heat radiation fins to withstand the tightening pressure, thereby preventing the enclosure case from cracking when the device is installed. be done.

In addition, since the resin inflow path is narrower than the depletion part, the pressure of the resin flowing into the depletion part is significantly lower than the pressure at the entrance of the resin inflow path, that is, the pressure of the resin on the inner wall of the case.
Resin does not leak to the outside through the depletion area. Even if the resin does not necessarily flow 100% into the void, or even if there are some cavities, the clamping pressure can be sufficiently withstood. However, it is desirable that the portion of the void portion to be filled with resin is filled to a point where the distance from the inner wall of the case is at least equal to the distance from the inner wall of the case to the center of the attachment hole.

(Example) As described above, in a semiconductor circuit device in which an envelope case is fitted to a radiation fin on which circuit components are mounted, and resin is filled and solidified,
A gap is created between the mounting fastening part of the case and the radiation fin due to thermal deformation of the case.

When this device is attached to an external support member, the gaps can cause cracking of the envelope case due to clamping pressure. The present invention attempts to prevent the case from cracking by filling the gap between the mounting and tightening parts with resin. First, the void area including the area where a gap is expected to be formed is directly connected to the inside of the case in the mounting and tightening part of the case. and injected the resin. The void was filled with resin, which was effective in preventing the case from cracking, but the drawback was that resin pressure within the void made it relatively easy for resin to leak to the outside through the gap between the case and the heat dissipation fin. was there. Therefore, instead of directly connecting the depletion part and the inside of the case, for example, a slit-shaped resin inflow path is provided between the hands to increase the resin inflow resistance and reduce the resin pressure in the depletion part compared to the resin pressure on the inner wall of the case. In this way, the resin leakage was improved and the present invention was completed.

An embodiment of the semiconductor circuit device of the present invention will be described below with reference to the drawings. FIG. 1(a) is a schematic cross-sectional view of this semiconductor circuit device using polygonal lines Δ, ・A2 ・A3, and the same figure (
b) is a partially fragmented plan view thereof. The circuit board 21 also serves as a heat dissipation fin and becomes the bottom plate of the envelope (hereinafter referred to as the heat dissipation fin 21).

A wiring pattern is formed on the radiation fin 21 via a ceramic sprayed film, and internal circuit components 22 including semiconductor elements are mounted thereon. An envelope case 23 is fitted onto the radiation fins 21 and filled with epoxy resin 24 to form an envelope of the device. In order to attach the device to an external support member, the envelope case 23 is provided with a mounting fastening portion 26, and a mounting hole 27 is formed to pass through the mounting fastening portion 26 and the radiation fin 21. The device is attached to the external support member by inserting a bolt or the like into the attachment hole 27 and tightening it.

FIG. 2 is an enlarged cross-sectional view of the mounting and tightening portion 26, and FIG. 3 is an enlarged plan view of the case upper part of the mounting and tightening portion 26 broken away.

In the present invention, a recess 1 is provided on the surface of the mounting fastening part on the side that contacts the heat radiation fin, separated from the mounting hole, and a depletion part 28 is formed by this recess and the heat radiation fin. Furthermore, a resin inflow path (referred to as a slit 29) is provided as a passage for connecting the depletion part 28 and the inside of the case, and when filling the case with the epoxy resin 24, the resin is also supplied to the depletion part 28 through the slit 29. Let it flow. The slit 29 allows a required amount of resin to flow into the depletion part, and is made narrower than the depletion part to reduce resin inflow pressure in the depletion part and prevent resin leakage. Therefore, in the present invention, the shapes of the depletion portion and the slit and the amount of resin inflow are important.

These vary mainly depending on the viscosity of the resin, so in actual implementation, the filling resin must be determined first.

In this example, the viscosity of the epoxy resin was 60,000 cps.
The effective shape and dimensions of the depletion part and slit were determined through trials. For example, the depth d of the depletion portion 28 = 2.35 mm, and the depth d of the slit 29.

-2 mm and width 1=21, good results were obtained with no case cracking when the device was installed and no resin leakage to the outside. As mentioned above, the amount of resin flowing into the cavity 28 does not necessarily have to be 100%, or even if there are some cavities, it can sufficiently withstand the tightening pressure. It is desirable that at least a straight line 118-8 parallel to the inner wall of the case is filled. Furthermore, the width of the contact surface between the case and the radiation fin between the mounting hole and the cavity must be set to an appropriate value, since if it is too narrow, resin leakage may occur even if the resin pressure in the cavity is reduced.

[Effects of the Invention] In the semiconductor circuit device of the present invention, a void portion including a gap due to thermal deformation of the case is provided between the mounting tightening portion of the envelope case and the heat radiation fin, and the resin is inserted into this void portion through a narrow slit. It has a structure that allows it to be filled with As a result, the tightening pressure of the case increased, and the case no longer cracked due to tightening during use, which had a significant effect on improving the reliability of the product.

In addition, since the resin injection pressure in the depletion area was reduced, there was no possibility that the resin would flow out from the gap between the heat radiation fin and the case and cause the product to be defective, making it possible to significantly improve the manufacturing yield.

[Brief explanation of the drawing]

1(a) and (b) are schematic cross-sectional views and partially exploded plan views of the semiconductor circuit device of the present invention, and FIG. 2 is an enlarged sectional view of the mounting and tightening portion of the semiconductor circuit device of FIG. 1. , FIG. 3 is a partially fragmented enlarged plan view of the mounting tightening part, FIGS. 4 and 5 are schematic cross-sectional views of a conventional semiconductor circuit device, and FIG. 6 is an enlarged cross-section RA1 of the mounting tightening part. It is a diagram. 1.21...Circuit board, (radiating fin), 2゜22
... (internal circuit parts), 3.23 ... Envelope case, 4.24 ... Resin (epoxy resin), 6゜2
6...Mounting tightening part, 7. ．． 27...Mounting hole, 2
8... Depletion part, 29... Resin inflow path (slit)
. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A circuit board on which circuit components including semiconductor elements are mounted and which also serves as the bottom plate of the envelope, an envelope case that fits with this circuit board and has a mounting fastening part, and a mounting fastening part of this envelope case. and the circuit board, a recess provided on a surface of the mounting fastening part of the envelope case on the side that comes into contact with the circuit board and separated from the mounting hole, and the circuit board. and a resin inflow path that communicates with the interior of the envelope case, and the cavity is filled with resin between the interior of the envelope case and the circuit board and the cavity. A semiconductor circuit device characterized by: