JPS6233343Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention relates to a lead frame, and particularly to a structure in which each die stage of a double lead frame is formed close to a central portion where the double lead frames are connected.

(2) Technology background Resin-encapsulated semiconductor integrated circuit (plastic IC)
(also referred to as a lead frame) is manufactured using the lead frame shown in FIG. In the figure, 1 is a lead frame, 2 is a cradle, 3 is a pilot hole, 4 is a die stage, 5 is a lead, and 6 is a pinch. A semiconductor chip (hereinafter referred to as a chip) (not shown) is attached to the top of the die stage 4 (die attachment), and a wire is bonded to the electrode pad of the chip and the end of the lead 5 near the die stage to form a connection ( After that, mold resin is sealed in the area surrounded by dotted lines in the figure, the tie bars and pinches are cut, and the leads are bent to form a plastic IC. Such techniques are known and widely practiced. Although FIG. 1 only shows one die stage and the upper part of the die stage in lead arrangement, a number of die stages are arranged side by side on the lead frame, and the lower part of the die stage is shown in the figure. and symmetrical leads are arranged.

Recently, in order to reduce costs and improve workability,
Multiple lead frames are used, and two lead frames are generally used. The structure of such a double lead frame is shown in plan view in FIG. Note that in FIG. 2 and subsequent figures, the same parts as those already illustrated are designated by the same reference numerals. The portion designated by the reference numeral 7 in FIG. 2 is the central portion of the double lead frame described above.

(3) Prior Art and Problems The wiring between the electrode pads and leads of the chip described above, that is, wire attachment, can be completed within a very short time by bonding ultrafine electric wires using an automatic bonding machine. In the case of a double lead frame, once the wire has been attached to the chip on the upper die stage in the diagram, the bonding machine moves to the position on the die stage of the lower lead frame and attaches the wire in the same way as described above. , then move to the next position on the die stage and repeat the same process in sequence.

Technology for shortening the time required to attach wires between chips and leads has been developed to the point where it is almost impossible to expect that the time will be reduced any further than at present. On the other hand, mechanically, we are making as much improvement as possible to shorten the time required for the automatic bonding machine to move from a position on one lead frame to a position on the other lead frame (transfer time). The situation is such that there is almost no room for improvement in bonding machines for both wire attachment and wire movement.

However, in order to reduce costs and improve workability as described above, there is a demand for shortening the moving time of the bonding machine. This is because, even if the time saved is extremely short, since the number of lead frames to which wires are attached is large, the accumulated time will result in a considerable reduction in time.

(4) Purpose of the invention In view of the above-mentioned conventional problems, the object of the present invention is to provide a multi-lead frame that can shorten the time required for wire attachment.

(5) Structure of the invention According to the invention, this object is achieved by providing a structure in which the die stage of each lead frame is brought closer to the central part where the lead frames are connected in a double lead frame.

(6) Examples of the invention Hereinafter, examples of the invention will be described in detail with reference to the drawings.

FIG. 3 shows a conventional double frame, and FIG. 4 shows a plan view of an embodiment of the present invention. These double lead frames are for decimal pins (8 to 16 pins).

The distance between the inside of the cradle 2 and the center of the die stage 4, and the center of the die stage 4 and the central part 7
are equal in the embodiment of FIG. If this distance is a, the bonding machine must move a distance of 2a to move from a position on the upper die stage to a position on the lower die stage as seen in the figure.

In the double lead frame according to the present invention,
The stage 4 is placed closer to the central portion 7 than in the conventional example. Therefore, the distance a' from the center of the die stage to the central portion 7 is smaller than a in FIG. 3 (a>a'). Therefore, the movement distance 2a' of the bonding machine in the example of FIG. 4 is smaller than in the example of FIG.

As a result of shifting the die stage as described above, the arrangement of the leads 5 cannot be vertically and horizontally symmetrical as in the conventional example, but becomes vertically asymmetrical as shown in FIG. Therefore, only the left half of the leads is shown in FIG. 5 for the sake of simplicity). However, the arrangement of the leads as shown in the drawings can be easily accomplished using current lead frame manufacturing technology, and there are no particular difficulties in implementing the present invention. In addition, although a double lead frame is taken as an example in the above, the scope of application of the present invention is not limited to that case.
This applies to lead frames as well.

(7) Effects of the invention As explained in detail above, according to the invention, the moving distance of the bonding machine and therefore the moving time are shortened. Because of this, the accumulated time saved is significant, and the effect of cost reduction in the production of plastic ICs is significant.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional lead frame, Figure 2 is a plan view of a conventional lead frame.
The figure is a plan view of a double lead frame, Figures 3 and 4.
The figure is a plan view showing the positions of the die stages of the conventional example and the embodiment of the present invention, and FIG. 5 is a plan view of a part of the double lead frame of the present invention. 1...Lead frame, 2...Cradle, 4
...Die stage, 5...Lead, 7...Central part of double lead frame.

Claims (1)

[Scope of utility model registration request] A multi-lead frame used for a resin-sealed semiconductor integrated circuit, characterized in that a die stage is arranged close to a central portion where two lead frames are connected.