JPH01227446A - Manufacture of wire plate - Google Patents

Abstract

PURPOSE:To mold a plate flatly, to plate the whole positively and to enable normal wire bonding by a method wherein the plate is punched molded into a state that a plurality of wire plates are connected mutually through a scribing line, shaped flatly and plated with silver, and each wire plate is detached. CONSTITUTION:When semiconductor chips placed onto a printed board, etc., are bonded, a plate is molded under the state, in which a plurality of wire plates 12 are mutually connected integrally through a scribing line 13 capable of being easily cut, by rapping the plate first. These wire plates 12 are shaped flatly by being flatly braided, the whole is plated with silver, etc., by being dipped in a plating bath, and respective wire plate 12 is detached along the scribing line 13. A rapped wire plate member 10 has each wire plate section 12 monolithic-molded at regular intervals on both sides of a central section 11 along the central section 11 extended in the longitudinal direction.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the manufacture of a wire plate that is placed adjacent to a semiconductor chip mounted on a printed circuit board etc. when performing wire bonding of the semiconductor chip. It is about the method.

[Conventional technology]

Generally, when mounting a semiconductor chip such as an LED chip on a printed circuit board, there is a gap between the top of the semiconductor chip and the top of the printed circuit board 3 formed on the printed circuit board with respect to the semiconductor chip mounted on the printed circuit board. The semiconductor chips are electrically connected by wire bonding with gold wires 5 or the like, but the semiconductor chips generate heat during operation.

For this reason, the semiconductor chip 1 is normally placed on a printed circuit board 3 with a metal heat sink 2 in between, as shown in FIG. For such a semiconductor chip l, a gold wire 5
If wire bonding is performed using a method such as the above, the heights of the top of the semiconductor chip 1 and the top surface of the printed circuit board 3 will be greatly different, so wire bonding using an automatic bonding machine is impossible. Therefore, in order to adjust the height of the bonding area of the printed circuit board 3 to the height of the top of the semiconductor chip 1, the wire plate 4 is fixed to the bonding area of the printed circuit board 3 with solder paste, and the upper surface of the wire plate 4 and the semiconductor chip Wire bonding is performed at approximately the same height as the top of the l, thereby making automatic bonding possible.

[Problem that the invention seeks to solve]

The wire plates 4 are usually formed by cutting out a flat plate, and the whole is immersed in a plating bath to give it a rough finish. However, since the wire plates 4 are very small in size, the wire plates 4 are formed into a ball-like shape. This may result in parts of the wire plate 4 not being silver-plated, making it virtually impossible to post-plating.Also, as shown in FIG. If a wire plate 4 deformed in this way is used, the wire plate will have a convex surface on one side and a concave surface on the other side due to the occurrence of cracks in the die cutting direction. Because of the convex and concave surfaces, there was a problem in that the gold wire 5 was not properly driven into the surface of the wire plate during bonding, making it impossible to perform normal wire bonding and lowering the bonding yield.

In view of the above points, the present invention' aims to provide a method for manufacturing a wire plate in which the wire plate can be formed flat, the entire wire plate can be reliably plated with silver, and normal wire bonding can be performed. The purpose is

[Means and actions for solving the problem] The above purpose is to
According to the present invention, in a method for manufacturing a wire plate that is placed adjacent to a semiconductor chip mounted on a printed circuit board or the like when bonding the semiconductor chip, a plurality of The wire plates are formed into a state in which they are integrally connected to each other via scribe lines that can be easily cut, and then these wire plates are flattened to form a flat shape, and the whole is immersed in a plating bath. This is accomplished by applying silver polishing or the like, and then cutting out each wire plate along the scribe line.

According to this invention, each wire plate is die-cut while being connected to each other, so that when immersed in a plating bath, each wire plate does not come into contact with each other and form a lump, and therefore, even after post-plating. This ensures that each wire plate is coated with silver plating, etc., and then each wire plate is easily separated from each other by folding along the scribe line, and during wire bonding, each wire plate is flattened after die cutting. Since the gold wire is shaped flat by hammering, the gold wire is reliably driven into the upper surface of the wire plate, and wire bonding is performed normally, improving the bonding yield.

〔Example〕

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows a wire plate member 10 cut out from a flat plate by the manufacturing method of the present invention. It has individual wire plate portions 12 integrally formed at equal intervals. Each wire plate portion 12 has a scribe line 1 as shown in FIG.
3 to the central portion 11, and can be easily separated from the central portion 11 by folding along the scribe line 13.

In the die-cut state, each wire plate portion 12 is
As shown in Figure 3, the die cutting direction (downward in the case shown)
The lower surface of the wire plate portion 12 has a concave surface, and the upper surface has a convex surface with an edge curved downward.

Here, the entire wire plate member 10 is flattened by flattening, whereby each wire plate portion 12 is shaped to be flat as shown in FIG. 4, that is, its upper and lower surfaces are flat. That will happen.

The wire plate member 10 flattened in this way is
The entire surface is immersed in a plating bath to be coated with silver plating, etc., and then the scribe line 13 described above is coated with silver.
By cutting off each wire plate portion 12 from the central portion 11 along the lines, each wire plate portion 12 constitutes an individual wire plate, thus completing the manufacture of the wire plate 12.

When the wire plate 12 manufactured in this way is used to wire bond a semiconductor chip as shown in FIG. 5, since the wire plate 12 is shaped flat, Wire bonding can now be performed reliably.

〔Effect of the invention〕

As described above, according to the present invention, when bonding a semiconductor chip mounted on a printed circuit board or the like, in a wire plate placed adjacent to the semiconductor chip, by first cutting out a flat plate, A plurality of wire plates are formed into a state in which they are integrally connected to each other via scribe lines that can be easily cut, and then these wire plates are flattened to form a flat shape, and the whole is immersed in a plating bath. After applying silver plating, etc., each wire plate is cut out along the scribe line, and the wire plates are cut out while being connected to each other. When immersed in water, each wire plate does not come into contact with each other and form a lump, so even after plating, each wire plate is reliably silver-plated, etc. By folding, the wire plates can be easily separated from each other. During wire bonding, each wire plate is shaped flat by flat punching after die cutting, so the gold wire is reliably driven into the top surface of the wire plate, and wire bonding can be performed correctly. As a result, the bonding yield is improved.

Thus, according to the present invention, by immersing each wire plate in a plating bath while connected to each other, the entire wire plate can be reliably silver plated, etc., and normal wire bonding can be performed by forming it flat. , an extremely superior wire plate can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a wire plate member cut out from a flat plate by the method of the present invention, FIG. 2 is a side view of the wire plate member in FIG. FIG. 4 is a sectional view of the wire plate portion after being punched out, and FIG. 4 is a sectional view of the wire plate portion after being flattened. FIG. 5 is a schematic cross-sectional view showing how a semiconductor chip is mounted using a conventional wire plate, and FIG. 6 is a cross-sectional view of the conventional wire plate. 1... Semiconductor chip; 2... Heat sink; 3...
Printed circuit board: 4...Wire plate: 10.
・・Wire plate member; 11 ・・Center part; 1
2...Wire plate part; 13...Scribe line.

Claims (1)

[Claims] In a method for manufacturing a wire plate that is placed adjacent to a semiconductor chip mounted on a printed circuit board etc. when bonding the semiconductor chip, a plurality of wire plates are easily cut by first cutting out a flat plate. These wire plates are formed into a state in which they are integrally connected to each other via scribe lines that can be used as a wire, and then these wire plates are flattened to form a flat shape, and the whole is immersed in a plating bath to be plated with silver, etc. After that, each wire plate is separated along the scribe line.