JPS62193159A - Insulating type semiconductor device and molding tool thereof - Google Patents

Abstract

PURPOSE:To improve packaging reliability, by increasing the thickness of a screw inserting hole part and a package part covering a chip, and partially decreasing the thickness of the package at the main surface of a header on the side of the screw inserting hole just like the package at the back surface of the header. CONSTITUTION:Leads 2 are protruded from a package 1. The other end part of the package 1 or the opposite side of said protruded part is made partially low by one step along the direction of the width. At the low part 3, resin is positively injected in the lower surface of a header when the resin is molded. Holes 4 are provided at the back surface of the low part 3 when the resin is molded. The holes 4 are filled with a hardened filler 5. A screw inserting hole 7 is provided at a part close to the low part 3 in the package. The hole 7 is used when an insulating type semiconductor device 6 is attached to an attaching plate. The resin at the package part is as thick as several mm. Therefore, even if a screw is inserted in the screw inserting hole and tightened with a large force when a power transistor is packaged, the resin part is not crushed with the tightening force. Cracks are not yielded and the resin is not peeled off. Thus the packaging reliability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulated semiconductor device and a mold type thereof.

[Conventional technology]

As a packaging technology for semiconductor devices, transfer resin molding technology, which is suitable for mass production, is often used. Regarding resin package type semiconductor devices, please refer to "Electronic Materials J, 1981, 1, published by Kogyo Research Association.
January issue, published November 1, 1980, described on pages 42 to 46.

This document describes the following: A TO-220 type semiconductor device is known as a resin package type semiconductor device. By the way, this To-2
When using a 20-inch semiconductor device mounted insulatively on a mounting plate, an insulator such as mica should be interposed between the header and the mounting plate, and an insulating tube should be inserted into the mounting hole provided in the header. Although the semiconductor device is fixed to the mounting plate by inserting mounting screws into the insulating tube, this structure requires a lot of time and effort during mounting. Therefore, insulated semiconductor devices have been developed in which the inner surface of the mounting hole is covered with insulating resin and the surface of the header is also covered with insulating resin so that the insulating tube does not need to be inserted. In addition, the resin thickness on the back side of the header in this insulated semiconductor device is desirably as thin as possible in order to improve heat dissipation while maintaining the desired dielectric breakdown voltage. For example, the thickness is 0.
It is approximately 35 to 0.45 mm.

[Problem that the invention seeks to solve]

In manufacturing the insulated semiconductor device, in order to ensure that the filling speed of the resin is the same on the main surface and the back surface of the header on which the chip is fixed, so that good packaging can be achieved, the main surface of the header is The resin thickness of the package is thick in the puff cage portion that covers the chip, and thin in the portion of the package where the screw insertion hole is provided.

However, the thinness of the resin in the parts that make up the screw insertion holes into which screws are inserted means that when securing an insulated semiconductor device to a mounting plate with screws, the screws must be tightened with great force or the screws must be tightened with great force. The inventors have revealed that when the board is warped, the thin resin part is crushed and cracks occur, or parts of the board peel off, resulting in a decrease in moisture resistance. For this reason, when mounting an insulated semiconductor device, care must be taken such as adjusting screw tightening, which makes the work cumbersome.

An object of the present invention is to provide an insulated semiconductor device with high mounting reliability.

Another object of the present invention is to provide an insulated semiconductor device with high dielectric breakdown voltage resistance.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in manufacturing the insulated semiconductor device of the present invention, the header is held in a floating state in a mold cavity, and resin is injected from one end of the cavity to coat the main and back surfaces of the header. When feeding resin into the header, the thickness of the package part where the screw insertion hole is provided and the package part that covers the chip etc. are both made to be X thick, and the main surface part of the header on the resin injection side is at least partially thickened. This ensures that the space on the back side of the header, which has a narrow thickness, is filled with resin.

[Effect]

According to the above means, the part of the package in which the screw insertion hole is provided is as thick as the part of the package that covers the chip, etc., so even if the tightening force of the screw inserted into the screw insertion hole is large, the resin The strength against crushing is improved, and the resin in the screw insertion hole does not break when an insulated semiconductor device is mounted, improving the reliability of mounting. In addition, during molding, the resin is squeezed on the main surface of the header on the resin injection side, so after or almost at the same time as the back side of the header is filled with resin, the main surface of the header is filled with resin. In the resin part on the back side of the header, where dielectric breakdown should not occur, there is no longer an abutting part where resin flows and collides and contacts each other, which improves the durability of insulated semiconductor devices. It becomes possible to manufacture an insulated semiconductor device with good reproducibility without reducing the dielectric breakdown voltage.

〔Example〕

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

FIG. 1 is a sectional view showing a resin mold state in manufacturing an insulated semiconductor device according to an embodiment of the present invention, and FIG. 2 is a perspective view similarly showing the insulated semiconductor device.

As shown in FIG. 2, the insulated semiconductor device (insulated power transistor) of this embodiment consists of a package l made of resin, and three ropes 2 protruding from one end surface of this package 1. It has become. Said package 1
The end opposite to the protruding end from which the lead 2 is protruded is partially lowered in the width direction. This lower part 3 will be the lower surface (back surface) of the header when resin molding is performed, which will be described later.
This is a result of ensuring that resin is injected into the area. In addition, there are holes 4 formed during resin molding on this low portion 3 and on the back surface of this low portion 3;
are filled with a filling material 5 that has been filled and hardened. Further, a screw insertion hole 7 is provided in a portion of the package 1 near the lower portion 3, which is used when attaching the insulated semiconductor device 6 (insulated power transistor 2, hereinafter also simply referred to as a transistor) to a mounting plate. There is.

Next, a method of molding this transistor 6 will be explained with reference to FIG.

Prior to molding this transistor 6, a metal lead frame 8 is prepared. This lead frame 8 is formed by patterning by cutting and forming a profiled material. In this embodiment, since the lead frame 8 is for assembling a To-3 type insulated power transistor, it includes a thick header 10 for fixing a chip (semiconductor element) 9 to its main surface, and a thick header 10 for fixing a chip (semiconductor element) 9 to its main surface. It has a collector lead 11 extending in a stepped manner from one end, and a small number of leads 2 extending parallel to both sides of the collector lead 11. Further, the side of the header 10 from which the collector lead 11 protrudes serves as a chip attachment area 12 for fixing the lug 9.

Further, a screw insertion hole forming hole 13 is provided at the end of the header away from the chip mounting area 2. This screw insertion hole forming hole 13 has a larger diameter than the screw insertion hole 7. Further, the screw insertion hole 7 is formed concentrically with the screw insertion hole forming hole 13.

A transistor 6 is made using such a lead frame 8.
When performing molding, the chip 9 is first fixed in the chip mounting area I2 of the lead frame 8, as shown in FIG. Next, the electrodes of the chip 9 and each lead 2 are connected with wires (not shown). Thereafter, this lead frame 8 is held between the upper die 15 and the lower die 16 of the mold die 14 and molded by resin injection. In this mold, a header 10 and leads 2 are placed in a cavity 17 formed by an upper mold I5 and a lower mold 16.
The inner edge etc. of will fit. The cavity 17 has a hole 13 on the end surface side of the header 10, that is, a hole 13 for forming a screw insertion hole.
Melted resin 19 is injected from a gate 18 provided on one end surface side as shown by dots.

In this resin mold, in the mold die 14, the upper die 15 and the lower die 16 are each provided with two protrusions 20, and these protrusions 20 form the header 10.
, so that the header 10 is lifted from the bottom surface of the cavity 17 by, for example, about 0.4 mm. As a result, after molding, a resin with a thickness of 0.4 mm is packaged on the back surface of the header 10, so that the transistor 6 can maintain a desired dielectric breakdown voltage. Furthermore, since the resin 19 must be reliably injected into the back side of the header 10, the portion of the upper mold 15 facing the gate 18 is lowered and a constricted portion 21 is formed. This constriction part 21 plays a role of adjusting the amount of resin 19 flowing into the main surface side of the package 1. That is, when injecting the resin, the main surface side of the header 10 is injected so that the resin 19 is not injected into the main surface side of the header 10 before the resin 19 fills the back surface side of the header 10, which has a narrow height of 9.4 mm. In order to prevent the poured resin 20 from flowing into the back side of the header 10,
The flow of the inflowing resin 19 is adjusted by the throttle section 21 so that the balance of the resin 19 does not collapse. Therefore, according to this mold 14, at the time when the resin 19 has flowed into the entire back surface side of the header 10, the resin 19 continues to flow into the main surface side of the header 10.

As a result, in the resin portion on the back side of the header 10, where dielectric breakdown should not occur, there is no abutting portion of the flowing resin 19, which is formed when the resin 19 flows into each other and collides with each other. The present inventor has clarified that the reliability of the insulation resistance is low in the part where the resin flow hits because macroscopically there is a gap at the collision interface.

On the other hand, a cylindrical body 22 is located in the cavity 17 at the end of the header 10. This cylindrical body 22 is molded into mold 1
4 (in this embodiment, the cylindrical body 22 is provided in the upper mold 15). The portion where this cylindrical body 22 is located becomes the screw insertion hole 7 after molding. Therefore, during molding, this cylindrical body 22 is attached to the spacing 10 so that a dielectric breakdown resistant layer is formed on the inner periphery of the screw insertion hole 7.
It is designed so that it does not come in contact with any part of the Also,
The separation distance is determined by the resin 1 formed on the back surface of the header 10.
The thickness is the same as or thicker than No. 9.

Next, after the molding is completed, the unnecessary portions of the lead frame 8 are cut and removed, and the transistor 6 as shown in FIG. 2 is manufactured.

According to such an embodiment, the following effects can be obtained.

(1) In the insulated power transistor of the present invention, the thickness of the resin in the package portion where the screw insertion hole is provided is several meters.
When mounting a power transistor, since it is as thick as approximately
Even if the screw inserted into the screw insertion hole is strongly tightened, the resin part will not be crushed by the tightening force, causing cranking or peeling of the resin, increasing the reliability of mounting. Effects can be obtained.

(2) Due to the above (1), when mounting the power transistor of the present invention, it is not necessary to pay much attention to tightening the screws, so that the workability of the mounting work can be improved.

(3) Due to the molded structure of the power transistor of the present invention, the resin part on the back side of the header, where dielectric breakdown should not occur, is covered with resin that flows into each other and collides with each other. Since there is no end point for the flow, pinholes and gaps will no longer occur.
The dielectric breakdown voltage can always be maintained high, resulting in higher reliability.

(4) According to the above (3), the power transistor of the present invention has no extremely small gap or the like in the resin portion on the back surface of the header, and therefore has the effect of increasing moisture resistance.

(5) According to the present invention, the constriction part for balancing resin injection is provided outside the chip mounting area of the header and outside the screw insertion hole, so the chip mounting area can be used effectively. , the effect is that chips of larger dimensions can be attached.

(6) According to the above (5), according to the present invention, since the chip mounting area can be effectively used in terms of area, the header can be miniaturized, or in other words, the transistor can be miniaturized. is obtained.

(7) According to (1) to (6) above, according to the present invention, it is possible to provide a power transistor that can fix a large chip, has excellent moisture resistance and insulation resistance, and has high mounting reliability. A synergistic effect can be obtained.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. For example, as shown in FIG. 3, the supporting protrusions 20 on the upper surface side of the header 10 for floating the header 10 from the bottom of the cavity 17 are made wide, and the presence of the protrusions 20 causes the resin 19 to Instead of flowing in the center of the header IO, the resin flow path may be narrowed and molding may be performed so that the resin flows on both sides of the header 10, as shown by the dashed line in FIG. In this case, as shown in FIG. 4, the thickness of the resin at the peripheral edge of the lower part 3 becomes thicker, and the mechanical strength of the edge of the package is improved. The area is filled with an insulator after molding.

The above explanation has mainly been about the case where the invention made by the present inventor is applied to the technology of insulated semiconductor devices, which is the background field of application, but the invention is not limited thereto. It can be applied to manufacturing technology for structured integrated circuit devices.

〔Effect of the invention〕

A brief description of the effects obtained by typical inventions disclosed in this application is as follows.

In the insulated semiconductor device of the present invention, the thickness of the package portion where the screw insertion hole is provided and the package portion that covers the chip etc. are both thick. Because it is thick like the package part that covers the screw insertion hole, even if the tightening force of the screw inserted into the screw insertion hole is large, the strength against resin crushing is improved, and the screw insertion hole part is thick when mounting an insulated semiconductor device. No damage to the resin occurs, improving mounting reliability. In addition, during molding in manufacturing the insulated semiconductor device of the present invention, the resin is squeezed on the main surface of the header on the resin injection side. In the resin part on the back side of the header, where the resin part on the back side of the header is filled with resin and there is no risk of dielectric breakdown, there is a contact area where the resin flows and collides with each other and comes into contact with each other. is no longer present, and the dielectric breakdown voltage strength is improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a resin mold state in manufacturing an insulated semiconductor device according to an embodiment of the present invention, FIG. 2 is a perspective view similarly showing an insulated semiconductor device, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view showing a state of resin molding in manufacturing an insulated semiconductor device according to an example, and FIG. 4 is a perspective view showing a product after resin molding. 1...Package, 2...Lead, 3...Low part,
4... Hole, 5... Filler, 6... Transistor,
7...Screw insertion hole, 8...Lead frame, 9...
- Chip, 10... Header, 11... Collector lead, 12... Chip mounting area, 13... Hole for forming screw insertion hole, 14... Mold mold, 15... Upper mold, 1
6... Lower mold, 17... Cavity, 18... Gate, 19... Resin, 20... Protrusion, 21... Squeezed part, 22... Cylindrical body. Figure 1 Figure 2 Figure 74 Figure 3 Figure 4! -High...17-Shi2-+Node3-Komezheng

Claims (1)

[Claims] 1. A package consisting of a header having a chip fixed to its main surface, a space region provided in the header for forming a screw insertion hole, and a resin covering the main surface and back surface of the header; The package includes a screw insertion hole provided in the package, and a lead extending inside and outside the package and having an inner end electrically connected to a corresponding electrode of the chip via a wire, and An insulated semiconductor device characterized in that the screw insertion hole is provided through the screw insertion hole forming space area without contacting the header, the package covering the screw insertion hole portion and the chip. An insulated semiconductor device characterized in that the thickness of the package on the main surface of the header on the screw insertion hole side is partially thinner, similar to the thickness of the package on the back side of the header. 2. A package consisting of a header with a chip fixed to its main surface, a space region provided in this header for forming a screw insertion hole, a resin covering the main surface and back surface of the insulating film header, and a package provided in this package. a screw insertion hole; a lead extending inside and outside the package and having an inner end electrically connected to a corresponding electrode of the chip via a wire;
A mold for manufacturing an insulated semiconductor device, wherein the screw insertion hole is provided through the screw insertion hole forming space region without contacting the header,
Both the chip covering part and the screw insertion hole forming part on the main surface of the header can be packaged thickly, and the main surface side of the header near the resin injection part is narrowed to increase resin flow resistance. A mold type characterized by having a section. 3. The area of the constricted portion is such that the resin that has flowed into the back surface of the header and the resin that has flowed into the main surface of the header do not meet on the back surface of the header. The mold according to claim 2.