JPS615529A - Insulated semiconductor device - Google Patents

Abstract

PURPOSE:To improve the reliability of mounting without damage of a thin portion by a bending stress due to clamping of a screw at mounting time by forming a groove interrupted by a thick rib at both ends at a header main surface side package to partition a chip fixing side and a screw inserting hole forming side. CONSTITUTION:A package 2 made of resin is formed with a limited groove 9 at both ends in the intermediate. The groove 9 is formed along the widthwise direction of the package, and formed at the position to partition between a chip mounting (chip securing) region and a region formed with a screw inserting hole. The both ends of the groove 9 are formed thickly in the same manner as a chip mounting region, and a rib 12 is formed as a reinforced member. A screw inserting hole 4 is formed substantially at the center of the package portion 10 with screw mounting side. Thus, even if the screw is strongly clamped at mounting time of a power transistor, the resin is not crushed by the clamping force, not separated, thereby enhancing the reliability of mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an insulated semiconductor device that can be directly mounted without performing insulation treatment during experiments.

[Background technology]

BACKGROUND ART Conventionally, transfer resin molding (molding) technology, which has excellent mass productivity, has been widely used as a packaging technology for semiconductor devices. Electronic materials are also used as a type of resin packaged semiconductor device.

Insulated semiconductor devices are known, as discussed in the article entitled "Encapsulation Resin for Power Transistors" by Yokohama et al., November 1981, pages 42-46. This insulated semiconductor device is similar to the conventional one (TO2
This was developed to reduce the hassle of mounting work on 20-inch) semiconductor devices. In addition to covering the inner circumferential surface with resin, the back of the header is covered with resin in order to reduce the time and effort of fixing the semiconductor device to the mounting plate by interposing an insulating plate such as mica on the back of the header. ing. 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, its thickness is 0
．． It is about 35' to 0.45m. moreover.

This insulated semiconductor device is designed to cover as much of the header as possible with the resin to prevent the intrusion of oxidizing substances (moisture, oxygen, etc.) that invade through the interface between the header and the resin. It has a structure.

On the other hand, the present applicant has also developed a similar insulated semiconductor device, but in this case, as shown in FIG. In order to make good packaging by equalizing the filling speed of the chips, the resin thickness of the package 2 on the main surface side of the header 1 is made thicker in the part of the package that covers the chip 3 (for example, 2 m), and the thickness of the package at the part with the screw insertion hole 4 is thin < (0,
(around 6th cabinet) was formed. Note that -5 in the figure is a lead.

However, the thinness of the resin in the portion that constitutes the screw insertion hole 4 into which the screw 6 is inserted makes it difficult to mount an insulated semiconductor device on the mounting plate 7 using the screw 6 and nut 8. The inventor has found that when the screws 6 are tightened with a large force, the thin resin portions are crushed and cracks occur, and the resin parts are partially peeled off, resulting in a decrease in moisture resistance. Therefore, when mounting an insulated semiconductor device, care must be taken, such as adjusting screw tightening.

Therefore, as shown in FIG. 2, the applicant has decided to reduce the thickness of the resin in the part of the package 2 where the screw insertion hole 4 is provided, in order to prevent the resin from being damaged by tightening the screw 6 during mounting. We are developing an insulated semiconductor device with a thicker structure. In addition, in the package shown in the same figure, the header 1 is adjusted so that the flow rate of the injected resin on the back surface side and the main surface side of the header 1 during resin molding is the same.
Since a drawing part is provided on the main surface side of the mold,
After φ, a groove 9 is formed in the upper part of the package 2. 1. The screw insertion hole 4 is provided approximately at the center of the side package portion 10 for screw attachment. In addition, this screw attachment is carried out on the side package part 10 because of the support protrusion placed in the mold to make the header l float above the bottom of the cavity of the mold during molding. The hole 11 is present in the hole 11.

However, when such an insulated semiconductor device is used, the flatness of the mounting plate used during mounting is poor.

Since the thickness of the register ν on the main surface side of the header 1 corresponding to the km groove portion is thin, for example, 0.5 to 0.0 mm, by tightening the screw 6, the thickness of the registration ν on the main surface side of the header 1 corresponding to the groove 9 is thin. The inventor has clarified that the resin may crack, and the reliability of the mounting will be lowered.

[Purpose of the invention]

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

In addition to the above-mentioned θ, other objects and novel features of the present invention are 1
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

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

That is, in the insulated semiconductor device of the present invention, the screw mounting side package portion provided with the screw insertion hole has a thick resin, similar to the package portion covering the chip;
The screws are tightened to prevent the resin from being crushed and damaged, and the ends of the thin resin part that extends between the package part that covers the chip and the side package part are tightened to improve mechanical strength. Since the ribs are partially thickened, the thin portions are less likely to break due to the bending stress caused by tightening the screws during mounting, and the reliability of mounting can be improved.

〔Example〕

FIG. 3 is a perspective view of an insulated semiconductor device according to an embodiment of the present invention, FIG. 4 is a perspective view showing the manufacturing state of the insulated semiconductor device, and FIG. 25 is a partial view taken along the line ■-■ in FIG. FIG. 6 is a partial sectional view taken along the line -Vl in FIG. 4.

As shown in FIG. 3, the insulated semiconductor device (insulated power transistor) of this embodiment includes a package 2 made of resin, and a 3.
It consists of book board 5 and. The package 2 is provided with a groove 9 having finite ends at both ends. This groove 9 is provided along the width direction of the package 2, and is provided at a position that separates a chip attachment (chip fixing) area from an area where a screw insertion hole is provided, as will be described later. Further, both end portions of the groove 9 are formed to be thick like the chip mounting area, and constitute ribs 12 as reinforcing members. In addition, the screw installation is on the side package part 10.
A screw insertion hole 4 is provided approximately at the center of the shaft. Also,
For this screw attachment, there is a hole 11 in the side package part 10 that is created during molding. The holes 11 are formed when the protrusions supporting the header 1 during molding are removed after molding, and therefore are formed on the main surface and the back surface of the header 1, respectively. In the embodiment, there are two on each of the main surface and the back surface of the package 2.

Next, a method for manufacturing this transistor will be described with reference to FIGS. 4 to 6, and further details of the transistor will be described.

In assembling this transistor, a lead frame 13 as shown in FIG. 4 is used. This bonded frame 13 is made by etching or pressing a metal plate with excellent heat dissipation properties, such as iron-nickel alloy, copper alloy, etc., with a thickness of about 0.1 to 0.25 mm. It is obtained by forming into a desired pattern and press molding. That is, the lead frame 13 has a thin frame part 14 and three leads 5 extending in parallel from one side of the frame part 14. The three leads 5 are connected by a thin dam 15 extending parallel to the frame portion 14. This dam piece 15 serves as a reinforcing member when the frame 13 is handled, and serves as a dam to prevent the injected resin from flowing out during resin molding. The tip portions of both side glueds 5 slightly protrude on both sides and are wide, forming wire connection portions 16. The purpose of the overhang of the wire connection portion 16 is to prevent the overhang from biting into the resin portion of the package 2 and to prevent the leads 5 from coming off from the package 2.

On the other hand, the center ladder 5 is bent downward one step and connected to the wide ladder 1. The side of the header 1 connected to the leads 5 is a chip mounting area 17 for fixing the chip (semiconductor element) 3. Further, the other end portion of the header 1 has thin arms 18 from both ends thereof. This arm 18 extends one step higher from the middle in a step-like manner, and serves as a height regulating piece 19 that defines the mold height of the spatula 1 during molding. Note that the space between the pair of arms 18 is a space 20 for forming a screw insertion hole.

When assembling a transistor using such a lead frame 13, the chip 3 is first fixed in a chip mounting area (chip fixing area) 17 of the lead frame 13, as shown in FIG.

Next, the electrodes of the chip 3 and each lead 5 are connected with wires 21. After that, this lead frame 13
As shown in the figure and FIG. 6, the mold 22 is held between the upper mold 23 and the lower mold 24. Inside the cavity 25 formed by the upper die 23 and the lower die 24, there is a portion of the lead frame 13 that is distal to the dam piece 15, that is, a header 1. The wire connection portion 16 and the like are accommodated therein. Then, melted resin 27 is press-fitted into the cavity 25 through the gate 26 located at the end of the header 1. At this time, since it is necessary to reliably inject the resin 27 also into the back side of the header 1, the height regulating piece 19 extending from the header 1 is connected to the support protrusion 28 which protrudes from the upper mold 23 and the lower mold 24. '29
Supported by Bottom of cavity 25 and spatula 1
For example, the distance between the back surface of the
．． In addition, a cylindrical body 30 is located in the cavity 25 between the pair of arms 18.

This cylindrical body 30 is provided separately in one or both of the upper mold 23 and the lower mold 24 of the mold die 22 (in this embodiment, the cylindrical body 30 is provided in the upper mold 23).

,). The portion where this cylindrical body 30 is located becomes the screw insertion hole 4 after molding.

Therefore, during molding, the cylindrical body 30 does not come into contact with any part of the spatula 1 so that a dielectric breakdown resistant layer is formed on the inner periphery of the screw insertion hole 4.

Further, the separation distance is equal to or thicker than the thickness of the resin 27 formed on the back surface of the spatula l.

On the other hand, in this embodiment, as shown in FIG. 6, a constriction part 31 is provided in a portion of the cavity 25 corresponding to the center of the main surface side of the ladder 1 so as to increase flow resistance of the resin 27. The constricted portion 31 is formed by the tip (lower end) of a plate-shaped orifice plate 32Φ protruding from the upper mold 23 and the main surface of the ladder l. Also, as shown in FIG.

This orifice plate 32 is not provided on both sides of the cavity 25, for example, over several widths. The part where this orifice plate 32 is not provided is made of resin 27.
is injected to form the ribs 12. What is the opening height of the aperture section 31?

Since the space on the main surface side of the header l is much larger than the space on the back side of the header l, it is necessary to pour a large amount of resin 27 into the main surface side of the header 1. The height and thickness of the space is larger than 0.4 mm, but before the resin 27 has filled the back side of the header 1, the resin 2 has flowed into the main surface side of the header ■.
It is necessary to regulate the flow of the resin 27 flowing into the constriction portion 31 so that the resin 27 does not flow into the back side of the header 1.

Therefore, according to this mold 22, when the resin 27 has flowed into the entire back surface side of the header 1, the resin 27 continues to flow into the main surface side of the header 1. As a result, the header 1, which should not cause dielectric breakdown,
In the resin portion on the back surface side, there is no abutting portion of the flow of the resin 27, which is formed when the resin 27 flows and collides with each other and comes into contact with each other. Microscopically, the collision interface at the end of this flow of resin is a gap.
The reliability of insulation resistance is low due to the presence of
It has been made clear by the present invention that N.

Next, after the molding is completed, the unnecessary parts of the 1-node frame 13, namely 1, the dam piece 15, and the frame part 14, are cut and removed, and a transistor as shown in FIG. 3 is manufactured. Ru.

FIG. 7 shows a perspective view of another embodiment of the invention.

The characteristic feature in the figure is that the height of the rib 12 is connected to the bottom surface of the groove 9 and the top surface of the package 2 b).This results in the same effect as in the previous embodiment, that is, Resin cracks & strong exposure; Highly reliable transistors can be provided. It should be noted that by adjusting the height of the rib 12, the filling speed of the resin 27 that is filled into the upper part of the chip mounting area 17 in the cavity 25 can be adjusted to further improve reliability. You can obtain a high IA product power of 1.

In addition, in the embodiment described above, 1 knob 12
The shape of b is a cube or a rectangular parallelepiped, but is not limited thereto, and may be a trapezoidal arc shape.

(Effects) 1. In the insulated power transistor of the present invention, the thickness of the resin at the rosette portion where the screw insertion hole 4 is provided is 21 mm.
When mounting a power transistor, even if the screw 6 is tightened strongly, the resin part will not be crushed by the tightening force and the resin will not crack or peel off, making it easy to mount the power transistor. This has the effect of increasing reliability.

2. From 1 above, when mounting the power transistor of the present invention, it is not necessary to pay much attention to tightening the screws, so that the effect of improving the workability of the mounting work can be obtained.

3. Due to the molded structure of the power transistor of the present invention, the resin 27 flows into the resin portion on the back side of the header l, where it is difficult to cause dielectric breakdown, and the resin 27 flows into each other and collides with each other, causing contact. Since there is no abutting part of the flow of the gin 27, the dielectric breakdown voltage can always be kept high, and the reliability of the dielectric strength can be improved.

4. From 3 above, 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 1, and therefore has the effect of increasing moisture resistance.

5. In the transistor of the present invention, the groove 9, which is inevitably generated during its manufacture, does not extend to both sides of the center of the package 2. Therefore, the thick resin portions at both ends of the groove 9, that is, the rib 12 portions act as mechanical reinforcing members.

The strength of the resin portion where the groove 9 is located is improved, the thin resin portion is not damaged even when the screw 6 is tightened during transistor mounting, and the reliability of the mounting is increased.

For example, if a piano wire with a diameter of 100 μm is placed on both sides of the lower surface of the package 2 in parallel with the lead 5, and the screw 6 is tightened with a torque of 10 kg-an, the part of the package 2 along the groove 9 is It has been confirmed through experiments that no cracks occur in the package (in the case of conventional products, cracks occurred in the 2 parts of the package along the groove 9 when tightening using piano wire with a diameter of 50 μm). .

6. According to the present invention according to 1 to 5 above, moisture resistance.

A synergistic effect can be obtained in that a power transistor with excellent insulation resistance and high mounting reliability can be provided.

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. Nor. For example, the present invention can be applied in the same manner as the mounting described above to an insulated semiconductor device having a structure in which the height regulating piece is cut at the surface portion of the package after molding, and similar effects can be obtained.

[Application field]

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 present invention is not limited thereto. It can be applied to manufacturing techniques for integrated circuit devices with a structure such as ``1''.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an outline of a conventional insulated semiconductor device, and FIG. 2 is a perspective view of an insulated semiconductor device developed by the applicant. 3 is a perspective view of an insulated semiconductor device according to an embodiment of the present invention, FIG. 4 is a perspective view showing the manufacturing state of the insulated semiconductor device, and FIG. 5 is a portion taken along the line ■-■ in FIG. 4. cross-sectional view. 6 is a partial sectional view taken along the line Vl--Vl in FIG. 4, and FIG. 7 is a perspective view of an insulated semiconductor device according to another embodiment of the present invention. 1... Header, 2... Package, 3... Chip, 4... Screw insertion hole, 5... Lead, 6... Screw, 7... Mounting plate, 8... Nut , 9... Groove, 10
...Screw installation is on the side package part, 11...hole, 1
2... Rib 513... Lead frame, 14...
Frame portion, 15... Dam piece, 16... Wire connection portion, 1
7... Chip attachment area, 18... Arm, 19...
・Height regulation piece, 20...Space for forming screw insertion hole, 21
...Wire, 22...Mold mold, 23...Upper mold, 24...Lower mold, 25...Cavity, 26...
Gate, 27...Resin, 28.29...Support protrusion, 30...Cylindrical body, 31...Aperture part, 32...Orifice plate.

Claims (1)

[Claims] 1. A package consisting of a header with a chip fixed to its main surface, a space area provided in this header for forming a screw insertion hole, a resin covering the main surface and back surface of the header, and a screw provided in this package. an insertion hole; 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 the screw insertion hole is connected to the header. This is an insulated semiconductor device characterized in that the header is provided through the space region for forming the screw insertion hole without contact, and the header is provided so as to separate the chip fixing side and the screw insertion hole forming side. An insulated semiconductor device characterized in that a front side package portion is provided with a groove whose both ends are blocked by thick ribs.