JPH07106349A - Manufacture of resin-molded semiconductor device - Google Patents

Abstract

PURPOSE:To enable the title power system resin molded semiconductor device to be composed of the totally automated line structure by a method wherein the assembling and finishing steps of the semiconductor device are connected by an automatical transfer system. CONSTITUTION:A chip is mounted on an island of a first hooped lead frame 1 and after wire-bonding, in order to secure the heat radiation capacity and the current capacity, a heat sink of a second lead frame is sticked on the island before the molding step 22 so that the thickness of the second lead frame may attain an equal or greater thickness of the conventional strip type lead frame.

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-molded semiconductor device, and more particularly to a method for manufacturing a power semiconductor device which requires heat dissipation because a semiconductor chip generates a large amount of heat.

[0002]

2. Description of the Related Art In a conventional lead frame used for manufacturing a power semiconductor device, the thickness of the island portion of the lead frame on which a chip is mounted is limited to 0.4 mm or more in order to secure heat dissipation and current capacity. Therefore, it is difficult to process the hoop of the lead frame, and the outer lead part is limited to about 0.5 mm in thickness due to the lead forming process and the mounting of the product. A strip-shaped deformed strip lead frame thickly processed to a required thickness was used. Figure 6
(A) to (c) are top views of the strip-shaped lead frame,
It is a front view and a side view.

In FIGS. 6A to 6C, a conventional strip-shaped lead frame 11 has an island 3A which also serves as a heat sink portion formed thicker than other leads 4A and the like. A case of manufacturing a semiconductor device using the strip-shaped lead frame 11 will be described with reference to the manufacturing line configuration diagram of FIG. 7 and the cross-sectional view of the semiconductor device of FIG.

First, the strip-shaped lead frame 11 is supplied from the magazine case 12 to the full auto mounter in the mounting step 20, the chip 7 is mounted, and the chip 7 is automatically transferred to the full automatic bonder in the bonding step 21.
The wire 8 is bonded to the electrode and the lead 4A.
The conveyance of the strip-shaped lead frame 11 to the next molding step 22, the setting in the molding die, and the like are performed by individual operations using a predetermined jig.

[0005]

As described above, in the conventional method for manufacturing a semiconductor device using a lead frame, since strip-shaped lead frames of different shapes having different thicknesses are partially used, the lead frame is processed. High cost.
In addition, since the upper and lower surfaces of the main plane pattern of the lead frame are integrally molded, it is difficult to perform resin molding by automatic conveyance after setting in the molding die. Therefore, there is a problem in that finishing processes such as outer lead plating, resin deburring, product mark, and tie bar cutting after the resin molding process must be individually processed. Although each of these steps itself is automated, it has been difficult to fully automate the entire line by using a strip-shaped lead frame of irregular shape.

[0006]

A method of manufacturing a resin-molded semiconductor device according to the present invention comprises a step of fixing a semiconductor chip to a surface of an island of a first lead frame having a hoop shape, an electrode of the semiconductor chip, and A step of connecting the leads of the first lead frame with a wire; and a step of adhering at least one heat sink portion provided on the hoop-shaped second lead frame to the back surface of the island to which the semiconductor chip is fixed. Is included.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a configuration diagram of a manufacturing line for explaining a first embodiment of the present invention, and FIGS. 2A and 2B are hoop-shaped first and second lead frames used in the first embodiment. FIG. 3 is a cross-sectional view of the resin mold type semiconductor device manufactured according to the first embodiment.

In FIGS. 2A and 2B, the first and second hoop-shaped lead frames 1 and 2 are 0.1 to 0.
It is made of a metal plate having a thickness of 35 mm, and the island 3 and the lead 4 are formed on the first lead frame.
A heat sink 5 is formed on the second lead frame 2. 6A is a positioning pin hole and 6B is a feed hole.

The plate thickness of the hoop-shaped lead frame is 0.1 m.
If it is less than m, a large number (4 or more) of lead frames need to be bonded to obtain the required plate thickness of the island part and the heat sink part, which complicates the assembly process of the product and increases the cost. . If the plate thickness of the hoop-shaped lead frame is 0.35 mm or more, the plate thickness becomes too thick and the inelasticity becomes strong, which makes it difficult to machine the hoop-shaped lead frame. Furthermore, since it is inelastically deformed by the hoop processing or an external force at the time of supplying to the assembly line, it is difficult to apply it to the assembly line. Hereinafter, description will be made with reference to FIGS.

First, the hoop-shaped first lead frame 1 is automatically supplied to the full automounter in the mounting step 20, and the chip 7 is AgPbS on the surface of the island 3.
After mounting with a soft solder made of n or the like, it is automatically conveyed to a fully automatic bonder in the bonding step 21, and an Al or Au wire 8 is bonded to the electrode of the chip 7 and the lead 4.

Next, the heat sink 5 of the second lead frame 2 is laminated on the back surface of the island 3 of the first lead frame 1 which has undergone the bonding process so as to be overlaid with a metal paste 9 or a conductive adhesive. Next, the positioning pin holes 6A of the respective lead frames are aligned and conveyed and supplied to the mold die of the full auto molder in the molding step 22, and the epoxy resin 10 having high thermal conductivity is used for molding.

In the following finishing process, resin deburring, lead molding, lead plating, tie bar cutting, etc. are automatically performed to complete the resin mold type semiconductor device.

In the above embodiment, the case where one heat sink portion of the second lead frame is bonded to the island portion of the first lead frame has been described.
You may stick two or more heat sink parts together. Also, the first
It is also possible to use the island portion of the lead frame as the heat sink portion.

As described above, according to the first embodiment, the heat sink portion is attached to the island portion immediately before the resin molding, thereby forming the same plane pattern as that of the conventional strip lead frame shown in FIG. 3 and the heatsink 5 can be pasted up to the same thickness or more, and the assembly and finishing process from mounting to tie bar cutting can be connected by an automatic transfer line without lowering heat dissipation and current capacity. Can be configured. For this reason, the number of handling steps between steps is reduced, and the number of personnel required for the line can be reduced to 1/3 to 1/4.

The lead frame is thin (about 0.1 mm).
(~ 0.3mm) It can be used together with an assembly processing line for small signal semiconductor devices that use hoop-shaped lead frames, and it is expected to reduce equipment costs and floor area. Furthermore, the strip-shaped lead frame of irregularly-shaped strip that is partially different in thickness, which has been conventionally used, cannot be made with a simple material and requires special processing, which is costly. Since the frame can be made of simple material, the cost per product can be greatly improved.

FIGS. 4A and 4B are top views of the first and second lead frames for explaining the second embodiment of the present invention, and FIGS. The difference is that the heat sink 5A is changed in shape and used for a self-standing resin mold package.

5 (a) and 5 (b) are a plan view and a sectional view of a resin mold type semiconductor device manufactured by the second embodiment.

Also in the second embodiment, as shown in FIG. 1, after the chip 7 is mounted on the island 3 of the first lead frame 1 and the wire 8 is bonded,
The heat sink 5A is attached to the back surface of the island 3 and molded with the resin 10.

As described above, according to the second embodiment, by changing the main plane pattern of the lead frame to the structure of the printed circuit board insertion mounting type self-standing resin mold package, the semiconductor device of the self-standing resin mold package can also be used. It is possible to construct a fully automated continuous processing line that automatically connects from mounting to tie bar cutting.

In the second embodiment, the first and second
The lead frame of (1) is bonded via an insulator 13 of a high heat conduction type, and is thermally connected directly under the chip. Further, a part of the heat sink 5A is exposed from the resin 10 to the outside to improve heat dissipation.

[0021]

As described above, according to the present invention, a plurality of hoop-shaped lead frames are used, and in order to secure the heat dissipation and the current capacity, the resin is formed so that the chip mount island portion and the heat sink portion have a required thickness. By bonding and assembling these in the process before sealing, it is possible to automatically transfer between the assembly and finishing processes by automatically supplying the hoop lead frame, and a fully automated line that connects all processes with the hoop lead frame. It is possible to significantly reduce the number of man-hours required for handling between processes and the number of personnel required for the line.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a manufacturing line for explaining a first embodiment of the present invention.

FIG. 2 is a top view of first and second lead frames used in the first embodiment.

FIG. 3 is a cross-sectional view of the semiconductor device manufactured in the first embodiment.

FIG. 4 is a top view of first and second lead frames used in a second embodiment of the present invention.

5A and 5B are a plan view and a cross-sectional view of a semiconductor device manufactured in a second embodiment.

FIG. 6 is a top view, a front view, and a side view of a strip-shaped lead frame used for manufacturing a conventional resin-molded semiconductor device.

FIG. 7 is a configuration diagram of a manufacturing line for explaining a conventional manufacturing method.

FIG. 8 is a sectional view of a semiconductor device manufactured by a conventional manufacturing method.

[Explanation of symbols]

 1 First Lead Frame 2, 2A Second Lead Frame 3, 3A Island 4, 4A Lead 5, 5A Heat Sink 6A Positioning Pin Hole 6B Feed Hole 7 Chip 8 Wire 9 Metal Paste 10 Resin 11 Strip Leadframe 12 Magazine Case 13 Insulator 20 Mounting process 21 Bonding process 22 Molding process

Claims (2)

[Claims] 1. A step of fixing a semiconductor chip to a surface of an island of a hoop-shaped first lead frame, a step of connecting an electrode of the semiconductor chip and a lead of the first lead frame with a wire, Bonding at least one heat sink portion provided on the second hoop-shaped lead frame to the back surface of the island to which the chip is fixed, the method for manufacturing a resin-molded semiconductor device. 2. The method for manufacturing a resin-molded semiconductor device according to claim 1, wherein the plate thickness of the first and second lead frames is 0.1 to 0.35 mm.