JPH04326755A - Resin-sealed semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a resin-sealed semiconductor device and a method for manufacturing the same in which the frequency of misrecognitions in a visual inspection of an automatic soldering can be largely reduced after the device is mounted on a printed board. CONSTITUTION:A plated film 3 which is satisfactorily melted with a solder 4a is formed at an end 2a of a lead pin 2 for bringing an electronic circuit element formed on a semiconductor chip into an electrical continuity with an external circuit wiring.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device and a method for manufacturing the same.

0002

2. Description of the Related Art In recent years, electronic devices have become significantly smaller and lighter, and higher-density packaging technology is required. Among these, surface mounting technology is widely used as a means of relatively easily achieving high-density mounting. In semiconductor devices as well, surface mount packages are becoming significantly smaller and thinner, and the lead width and lead pitch of lead pins are becoming increasingly narrower. Along with this, it has become impossible to visually inspect the appearance of soldering after a semiconductor device is soldered to an external printed circuit board, and automation is progressing. In the automatic soldering appearance inspection method, the quality of soldering is inspected by checking the solder wet state of the tip of the lead pin of a resin-sealed semiconductor device, and it is essential that the tip of the lead pin be coated with solder.

A conventional resin-sealed semiconductor device and its manufacturing method will be explained below. FIG. 5 is a sectional view of a main part of a package in which a conventional resin-sealed semiconductor device is soldered onto a printed circuit board. In FIG. 5, 1 is a semiconductor chip (
(not shown) and a sealing resin that seals a part of the lead frame; 2 is a lead pin for establishing electrical continuity between an electronic circuit element (not shown) formed on the semiconductor chip and an external circuit; 2a is the tip of the lead pin 2, 3 is a solder plating film for making the solder easily fit onto the lead pin 2 during solder mounting, and 4 is a solder for connecting the lead pin 2 and the circuit terminal 5 on the printed circuit board 6. . As shown in FIG. 5, a solder plating film 3 is formed on the tip 2a of the lead pin 2.
There is no solder 4 left, so solder 4 is not attached.

FIG. 6A is a plan view of a main part of a conventional resin-sealed semiconductor device before lead frame processing, and FIG. 6B is a sectional view of a main part of the same resin-sealed semiconductor device. As shown in these figures, the lead pin 2 is fixed by a connecting portion 2b of the lead frame. Note that 7 is a dam bar that suppresses the flow of resin during the resin sealing process.

FIG. 7(a) is a plan view of the main parts for explaining the method for manufacturing a resin-sealed semiconductor device, and FIG. 7(b) is a plan view for explaining the method for manufacturing the resin-sealed semiconductor device. FIG. In these figures, 8 is an upper mold for bending and molding the lead, 9 is a lower mold for molding the lead in the same way, and 1
0 is a cutter that cuts the tip of the lead. In the conventional lead forming method used in the assembly process of resin-sealed semiconductor devices, after the semiconductor chip and part of the lead frame are sealed with resin, the lead pins 2 exposed from the sealing resin 1 are plated with solder, and then the dam bar 7 is plated with solder. After cutting, the lead pin 2 was fixed with the upper mold 8 and the lower mold 9, and the cutter 10 was moved in the direction indicated by A to cut the connecting portion 2b of the lead frame.

[0006]

However, the conventional structure described above has a problem in that the solder 4 is difficult to adhere to the tip portion 2a of the lead pin 2 when it is mounted on the printed circuit board 6 by solder.

The present invention solves the above-mentioned conventional problems, and provides a resin-encapsulated semiconductor device and a resin-encapsulated semiconductor device that can significantly reduce the rate of misrecognition during automatic soldering visual inspection of resin-encapsulated semiconductor devices mounted on printed circuit boards. The purpose is to provide a manufacturing method thereof.

[0008]

[Means for Solving the Problems] A resin-sealed semiconductor device of the present invention to achieve this object has a structure in which a plating film is left on the tip of a lead pin protruding from the sealing resin, In addition, the manufacturing method is such that the lead pin, excluding the side bar for fixing the lead pin whose tip is at least an open end, is sandwiched and fixed between a comb-shaped upper mold and a lower mold. The method includes the step of cutting the dam bar and the side bar using a cutter that fits into the gap between the molds.

[0009]

[Effect] This configuration allows a plating film to remain on the tip of the lead pin, making it easier for solder to adhere to the tip of the lead pin when mounted on a printed circuit board, and increasing the rate of misrecognition by automatic soldering visual inspection equipment. can be reduced.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part of a package in which a resin-sealed semiconductor device according to an embodiment of the present invention is soldered onto a printed circuit board. Note that the same parts as in the conventional example shown in FIG. 5 are given the same reference numerals, and detailed explanations are omitted. This embodiment differs from the conventional example in that a solder 4a is attached to the tip 2a of the lead pin 2.

FIG. 2(a) is a plan view of the main parts of a resin-sealed semiconductor device before lead frame processing according to an embodiment of the present invention, and FIG. 2(b) is a cross-sectional view of the main parts of the same resin-sealed semiconductor device. It is a diagram. The lead pin 2 protruding from the sealing resin 1 is provided with a dam bar 7 for preventing resin from flowing during the resin sealing process and a side bar 11 for fixing the lead pin 2. In the lead pin 2 having such a configuration, the tip portion 2a
Since the solder plating film 3 is formed to the extent that the resin-sealed semiconductor device is soldered to the external printed circuit board 6, the solder 4a easily adheres to the tip portion 2a.

FIG. 3(a) is a plan view of a main part for explaining a method of manufacturing a resin-sealed semiconductor device according to an embodiment of the present invention, and FIG. 3(b) is a plan view of the manufacturing method of the same resin-sealed semiconductor device. FIG. 3 is a sectional view of a main part for explaining the method. In these figures, 8 is an upper mold for bending and shaping the leads, 9 is a lower mold for molding the leads, and 10 is a cutter. Upper mold 8
, the lower die 9 and the cutter 10 are both provided with unevenness, and the unevenness of the upper die 8 and the lower die 9 match,
The convex portion of the cutter 10 is adapted to fit into the concave portion. In the manufacturing method of this embodiment, first, a semiconductor chip (not shown) is mounted on a predetermined area of a lead frame, and after connecting the electrodes of the semiconductor chip and lead pins 2, a part of the semiconductor chip and lead pins 2 are sealed with resin. Stop. Next, the lead pins 2 exposed from the sealing resin 1 are plated with solder, and then the dam bar 7 is cut. Next, the side bars 11 of the lead pins 2 are cut using the upper mold 8 and the lower mold 9 provided with projections and depressions, and the cutter 10. Note that the cutting direction may be such that the cutter 10 is moved from above to below as indicated by A, or may be cut from below to above. Note that solder plating may be performed after cutting the dam bar 7 and before cutting the side bar 11. As described above, according to this embodiment, the lead pin 2 can be molded while ensuring its flatness, and at the same time, the solder plating film can be left on the entire surface of the tip 2a of the lead pin 2 of the resin-sealed semiconductor device. Note that the same effect can be obtained even if the position and shape of the side bar 11 are changed as shown in FIGS. 4(a) to 4(e). In Fig. 4(a), the side bar 11 is connected to the lead pin 2.
When the side bar 11 is positioned near the tip of the lead pin 2, FIG.
c) shows the case where the side bar 11 is located in the lower half of the lead pin 2, and Fig. 4 (d) shows the case where the side bar 11 is made thinner.
When positioned at the center, FIG. 4(e) shows a case where the side bar 11 is in a vertically elongated shape.

[0013]

[Effects of the Invention] As described above, the present invention leaves a plating film on the tip of the lead pin, making it easier for solder to adhere to the tip, and greatly reducing the rate of misrecognition during automatic soldering visual inspection. This makes it possible to realize an excellent resin-sealed semiconductor device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a package in which a resin-sealed semiconductor device is soldered onto a printed circuit board according to an embodiment of the present invention.

FIG. 2(a) is a plan view of the main parts of a resin-sealed semiconductor device before lead frame processing according to an embodiment of the present invention; FIG.
) is a cross-sectional view of the main parts of the same resin-sealed semiconductor device.

[Figure 3] (a
) is a plan view of a main part for explaining a method for manufacturing a resin-sealed semiconductor device according to an embodiment of the present invention; (b) is a cross-sectional view of a main part for explaining a method for manufacturing a resin-sealed semiconductor device.

[Figure 4] (a) to (e) are diagrams showing the position and shape of the sidebar, respectively.

[Figure 5] A cross-sectional view of the main parts of a packaged body in which a conventional resin-sealed semiconductor device is soldered onto a printed circuit board.

FIG. 6 (a) is a plan view of the main parts of a conventional resin-sealed semiconductor device before lead frame processing; (b) is a cross-sectional view of the main parts of the same resin-sealed semiconductor device;

[Figure 7]
(a) is a plan view of the main parts for explaining the manufacturing method of the resin-sealed semiconductor device; (b) is a cross-sectional view of the main parts for explaining the manufacturing method of the resin-sealed semiconductor device.

[Explanation of symbols]

2 Lead pin 2a Tip 3 Solder plating film (plating film) 4 Solder 4a Solder

Claims (2)

[Claims] 1. A resin-sealed semiconductor device in which a plating film that is compatible with solder is provided at the tip of a lead pin for electrically connecting an electronic circuit element formed on a semiconductor chip and external circuit wiring. . 2. The tip of the lead pin protruding from the sealing resin is an open end, the tip has a plating film that is compatible with solder, and the lead pin is fixed near the tip. A lead frame provided with a side bar, at least an area excluding the side bar, is sandwiched and fixed between a comb-shaped upper mold and a lower mold, and a cutter is fitted into the gap between the upper mold and the lower mold. 1. A method for manufacturing a resin-sealed semiconductor device, the method comprising the step of cutting the side bar using a resin-sealed semiconductor device.