JPS63148667A - Manufacture of lead frame - Google Patents

Abstract

PURPOSE:To densify an inner pattern part, by forming parts exclusive of the inner pattern part including an inner lead part by press working and then forming the inner pattern part by etching work. CONSTITUTION:Parts exclusive of an inner pattern part 8 including an inner lead part 2 are formed by press work, and then the inner pattern part 8 is formed by etching work, and hence both advantages of the press work and the etching work can be assembled. Namely, later processes such as etching work and assembly of semiconductor device are performed with high precision by the use of high-precision guide holes 6 on rail parts 5, and besides a multi-pin lead frame 10 with the inner pattern parts 8 densified can be easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a lead frame using a combination of pressing and etching.

(Prior Art) Current lead frame forming methods include etching and press working.

The method for manufacturing lead frames by etching involves forming a resist at the same position on both sides of a metal plate for lead frame manufacturing, and then treating it with an etching solution to simultaneously etch the areas without resist on both sides. . In this case, the etched portion is the lead spacing.

In press working, strip-shaped metal plates for lead frame production are sequentially punched out using a die.

Each of these processing methods has significant advantages.

For example, in press working, the precision of the guide holes in the rail section for feeding during lead frame processing is good. Further, the dam bar of the lead frame after molding can be easily cut, and no mold flash remains attached to the side surface of the external lead portion near the resin molded portion.

On the other hand, etching processing can realize miniaturization of inner pattern portions including internal leads in response to the demand for increased pin count in semiconductor devices.

(Problems to be Solved by the Invention) By adopting the advantages of the above-mentioned press working and etching process, it is possible to overcome the disadvantage of press working, which is that it is difficult to make the inner pattern part fine, and the disadvantage of etching process, which is the etching part. Because the sides cannot be formed into flat surfaces,
It is possible to eliminate the problem of mold flash adhering to the side surface of the external lead part near the resin mold part, making it impossible to perform necessary surface treatments such as plating.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for manufacturing a lead frame in which the outer lead portion of the lead frame is pressed and the inner lead portion is etched to achieve higher precision and higher density of the inner pattern portion. With the goal.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes the following configuration.

That is, the present invention is characterized in that after forming the parts other than the inner pattern part including the internal lead part by press working, the inner pattern part is formed by etching process.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows a part of a lead frame 10 used in a resin-sealed semiconductor device.

In the figure, reference numeral 9 denotes a stage portion, which is plated with a noble metal such as gold or silver, and is a portion to which a semiconductor element is fixed using a gold-silicon eutectic alloy or the like.

Reference numeral 2 denotes an internal lead section provided surrounding the stage section 9, the tips of which are similarly plated with a noble metal such as gold or silver, and connected to the semiconductor element mounted on the stage section 9 by wires. Moreover, the part surrounded by the broken line is the inner pattern part 8.

Reference numeral 3 designates an external lead portion following the internal lead portion 2 .

A dam bar 4 serves to dam the resin during resin sealing.

Reference numeral 5 denotes a rail portion, in which guide holes 6 are bored at predetermined positions.

First, the external lead part 3 other than the inner pattern part 8,
The dam bar 4, rail portion 5, and guide hole 6 are pressed and processed as shown in FIG. 1(a).

Thereafter, the inner pattern portion 8 is positioned with reference to the guide hole 6 formed by pressing, and the inner pattern portion 8 is etched to form a predetermined shape as shown in FIG. 1(b).

After that, plating treatment, bending and cutting, etc. are performed.

Note that although the shapes of the inner pattern portions 8 formed by etching are different, there are also lead frames in which the shapes of the outer lead portions 3, etc. are common, and in such cases, the common portions are processed by pressing, and the inner pattern portions are It is only necessary to etch each of them, and they can be suitably used. Further, the present invention can also be applied to a lead frame without a stage portion used in a low melting point glass-sealed semiconductor device.

(Effects of the Invention) As described above, in the present invention, parts other than the inner pattern part including the internal lead part are formed by press working, and then the inner pattern part is formed by etching process, so that the press work and the etching process can be combined. Benefits can be combined.

In other words, using the high-precision guide holes in the rail section, post-processes such as etching processing and semiconductor device assembly can be performed with high precision, and it is also possible to easily manufacture multi-pin lead frames with finer inner pattern shapes. can be manufactured.

Furthermore, when a semiconductor element or the like is resin-sealed using the lead frame manufactured in this way, the dam bar can be easily cut and the desired surface treatment can be applied to the side surface of the external lead part near the resin mold part. I can do it.

Furthermore, it is suitable for high-mix, low-volume production where the shapes of the inner pattern parts are different, but the pressed parts, such as the external lead parts, are common.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are partial perspective views of a lead frame showing processing steps for the lead frame, and FIG. 2 is a partial front view of the lead frame. 2... Internal lead part, 3... External lead part, 4
...Dam bar, 5...Rail part, 6...Guide hole, 8...Inner pattern part, 9...
Stage part, 10... Lead frame.

Claims (1)

[Claims] 1. A method for manufacturing a lead frame, which comprises forming parts other than the inner pattern part including the internal lead part by press working, and then forming the inner pattern part by etching process.