JPH0637227A - Method of manufacturing resin sealed semiconductor device and lead frame - Google Patents

Abstract

PURPOSE:To avoid the cracking in a sealing resin in the cutting off step by a method wherein the connecting parts of lead pieces of a lead frame and a tie bar are processed to be easily cut off and after finishing the resin molding step, the tie bar is removed to eliminate the large cutting off press for reducing the wear of a cutting off metallic mold. CONSTITUTION:A lead frame 1 is to be formed by cutting off lead pieces 2 and a tie bar 5 at the connecting part A to be force-fitted again into the original positions. Thus, the lead pieces 2 and the tiebar 5 are apparently coupled with one another in the state to be easlily separated from one another at the connecting part A. Next, semiconductor chips are mounted on a metal holding sheets 1 using such a lead frame so as to connect the other parts for the formation of sealing resin 6. Next, after finishing the resin molding step, the tie bar 5 and a side rail 3 are removed to be separated into indivivual semiconductor device. Accordingly, the tie bar 5 can be removed so easily by cutting off or pressing down the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a resin-encapsulated semiconductor device and a lead frame used therefor.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of a large number of resin-encapsulated semiconductor devices, required lead pieces are efficiently produced in a small number of steps, mass production is possible, and price reduction is achieved.
A manufacturing method using a lead frame is widely used.

FIG. 1 is a structural diagram of a conventional general lead frame. For example, a copper plate having a thickness of 0.5 m (2) m is manufactured by pressing, 1 is a metal supporting plate on which a semiconductor chip (not shown) is mounted, 2 is a lead piece for external connection, 3 is a side rail for connecting the lead pieces at their ends, 4 is a pilot hole which serves as a guide used during the lead frame processing and during the manufacture of the resin-sealed semiconductor device, and 5 is each reel of 2. -A tie bar that is located between the lead pieces and connects the lead pieces 2 together. The shapes and the numbers of the respective parts such as the metal supporting plate 1 and the lead piece 2 are merely examples, and the lead piece portion located above the lead piece 2, that is, above the tie bar 5 in the figure is selected. To mount a semiconductor chip,
A connector or the like is connected to the remaining portion.

FIG. 2 shows the structure of the lead frame after resin molding in which a semiconductor chip, a connector and the like are connected to predetermined positions on the lead frame of FIG. 1 and a sealing resin 6 is formed. It is a figure. The tie bar 5 functions to prevent the resin from flowing out at the time of resin molding by the transfer molding method or the like. The same reference numerals in the drawings represent the same parts. (The same shall apply to the following drawings.)

FIG. 3 shows a tie bar 5 of the lead frame after the resin molding shown in FIG. 2 by a dedicated cutting die not shown.
3 is a structural diagram after the side rail 3 is cut off and separated into individual resin-sealed semiconductor devices.

[0006]

In the process of cutting and removing the tie bar after the resin molding, a large cutting press is required, the wear of the cutting die is severe, and excessive stress at the time of cutting is caused. However, cracks are likely to occur in the sealing resin, which causes problems such as lack of reliability.

[0007]

SUMMARY OF THE INVENTION The present invention is a lead frame
In the method (3) for manufacturing a large number of resin-encapsulated semiconductor devices by using a frame, the connecting portion between the lead piece of the lead frame and the tie bar is processed in advance so that it can be easily separated. A manufacturing method characterized by removing the tie bar after the molding, and a lead frame therefor, further comprising a temporary fixing process for the connecting portion and a processing for forming a weak portion of the crystal structure. The dframe. By these, the above-mentioned problems are solved, and a method for manufacturing a resin-sealed semiconductor device, which is rich in mass productivity, and economical, and a lead frame are provided.

[0008]

FIG. 4 shows a lead frame according to an embodiment of the present invention.
FIG. 3 is a structural view of the frame, (a) is a plan view, (b) is a cross-sectional view of the lead piece 2 and the tie bar 5 when being cut, and (c) is a press-fit state of the lead piece 2 and the tie bar 5. It is an XX sectional view.

The lead frame used in the manufacturing method of the present invention is cut at the connecting portion A between the lead piece 2 and the tie bar 5 as shown in FIG. 4 (b), and then as shown in FIG. 4 (c). , Again so that it is formed so as to be pressed into the original position again. Therefore, although the lead piece 2 and the tie bar 5 are apparently joined at the connecting portion A,
Makes it easy to separate. Using a lead frame as shown in FIG. 4 (a), a semiconductor chip is placed on the metal supporting plate 1 and other components such as connectors are connected in the same manner as in the conventional case, and the sealing resin 6 is applied. Form. Then, after resin molding, tie bar
5 and the side rail 3 are removed to separate individual semiconductor devices as shown in FIG. According to the manufacturing method of the present invention, the removal of the tie bar 5 becomes extremely easy and can be realized by cutting or pressing with less stress, and the above-mentioned problems are solved.

FIGS. 5 and 6 are cross-sectional structural views of another embodiment of the lead frame of the present invention. In the connecting portion A in FIG. 5, the weak portion 10 of the metal crystal structure is formed between the lead piece 2 and the tie bar 5 by pressing or the like. Therefore, the lead frame can break the tie bar 5 with a slight stress. In order to make the connecting portion A into the weak portion 10, in addition to causing mechanical shear strain,
It can also be formed by a chemical corrosion method (4).

The connecting portion A in FIG. 6 is a thin portion formed by the notch 7 from above and below, and exhibits the same effect as in FIG.

Due to the progress of the manufacturing process, transportation of the lead frame,
It is a manufacturing obstacle that the connecting portion A is easily separated before the resin mold in moving or the like. Therefore, as shown in the plan view of the lead frame of FIGS.
By providing the uneven portion 8 (FIG. 7) or the caulking portion 9 on the connecting portion A (FIG. 8), temporary fastening processing for reinforcing the mechanical strength can be performed.

The structure of the embodiment of the present invention can be variously modified within the scope of the gist of the present invention. For example, when the semiconductor device is separated into individual semiconductor devices, the number of lead pieces to be led out to the outside is four. It is not limited to books. Also, a metal support plate in the sealing resin,
The shape of the lead piece or the like, the positional relationship, addition of parts, and the like can be arbitrarily selected according to the design needs. Further, the lead piece of the resin-encapsulated semiconductor device according to the present invention is as shown in FIG.
The present invention is not limited to the one derived from one surface of the sealing resin, and can be applied to the one derived from a plurality of surfaces.

[0014]

Industrial Applicability As described above, a method of manufacturing a resin-encapsulated semiconductor device, which is rich in mass productivity, and economical, and a reel.
The present invention is applied to the manufacture of semiconductor devices such as rectifying diodes, transistors, thyristors, and ICs because it provides a dframe, and its industrial application effect is extremely great.

[Brief description of drawings]

FIG. 1 is a structural diagram of a conventional lead frame.

FIG. 2 (5) is a structural diagram of a conventional lead frame after resin molding.

FIG. 3 is a structural diagram in which individual resin-encapsulated semiconductor devices are separated.

4A and 4B are structural views of a lead frame according to an embodiment of the present invention. FIG. 4A is a plan view, FIG. 4B is a sectional view when the tie bar is cut, and FIG. It is an X sectional view.

FIG. 5 is a sectional structural view of a lead frame according to another embodiment of the present invention.

FIG. 6 is a sectional structural view of a lead frame according to another embodiment of the present invention.

FIG. 7 is a plan view of a lead frame according to another embodiment of the present invention.

FIG. 8 is a plan view of a lead frame according to another embodiment of the present invention.

[Explanation of symbols]

 1 Metal support plate 2 Lead piece 3 Side rail 4 Pilot hole 5 Tie bar 6 Sealing resin 7 Notch 8 Uneven part 9 Caulking part 10 Weak part A Connecting part

Claims (4)

[Claims] 1. A semiconductor device is assembled by using a lead frame in which a plurality of lead pieces including a lead piece from a metal supporting plate on which a semiconductor chip is mounted are connected by a tie bar, and a resin mold is assembled.
In the method of manufacturing a resin-sealed type semiconductor device in which the tie bar is cut off after the assembly and separated into individual semiconductor devices, the connecting portion of the tie bar of the lead frame and the lead piece can be easily separated in advance. And the tie bar is removed after the resin molding. 2. A lead frame, wherein a connecting portion of the tie bar and the lead piece is processed in advance so as to be easily separated. 3. The lead frame according to claim 2, wherein the connecting portion is formed by press fitting or temporary fastening such as caulking. 4. The method according to claim 2, wherein the connecting portion is formed by processing to make a weak portion or a thin portion of the crystal structure.
Lead frame.