JP3278861B2 - Method for manufacturing lead frame for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a lead frame for a semiconductor device, and more particularly to a method of manufacturing a lead frame for a semiconductor device in which the positions of internal leads are less shifted by a punching process.

[0002]

2. Description of the Related Art In general, a lead frame for a semiconductor device is formed through various punching, punching, and the like using a progressive die. When a lead frame is formed, the internal lead is shifted from a design position during punching as shown in FIG. 4 (an enlarged plan view of the internal lead portion of the lead frame). That is, the punched portion 14 is removed by punching to form the internal lead 12, but at this time, the side surface of the internal lead is shifted from the original design position shown by the dotted line to the position shown by the solid line. If the deviation from the design position is large, it will be an obstacle to wire bonding at the time of assembling the semiconductor. Therefore, an acceptance standard is set for a deviation from a design position of the internal lead (hereinafter referred to as a lead shift).

For this reason, conventionally, when the lead shift does not satisfy the acceptance standard, a correction step is provided near the last stroke of the progressive die for punching the lead frame, and the lead shift is corrected so as to approach the original design position. . This lead shift correcting step is, as shown in FIG. 5 (an enlarged plan view of the internal lead portion of the lead frame) and FIG. 6 (a cross-sectional view along line 6-6 in FIG. 5) after the formation of the internal lead. This is a step of performing plastic working with a convex jig so as to give a concave shape to a position where a lead shift is expected to be small. Therefore, the formed concave portion remains as a scratch on the internal lead.

[0004]

As described above, a lead shift generated in a lead frame by punching a progressive die can be empirically corrected by a conventional method. However, in the conventional correction method, the correction amount is large, it is difficult to make a minute correction, and deformation may be given in other directions, so that adjustment is difficult. Furthermore, there is a disadvantage that strength is reduced because concave scratches remain on the internal leads.
Furthermore, it is conceivable that the electrical characteristics change.

Accordingly, it is an object of the present invention to provide a novel method for manufacturing a lead frame for a semiconductor device which does not leave a concave scratch having the above-mentioned disadvantage.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a method for manufacturing a lead frame for a semiconductor device, comprising the steps of: A method of manufacturing a lead frame for a semiconductor device, comprising: a step of forming a groove in a root portion of an internal lead that becomes a waste; and a step of removing an extracted waste portion by punching to form an internal lead. To adopt.

Preferably, the groove has a V-shaped cross section.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of a method for manufacturing a lead frame for a semiconductor device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of the entire lead frame, and FIG.
FIG. 3 is a cross-sectional view taken along line 3-3 in FIG.

According to the present invention, a groove, preferably a groove 1 having a V-shaped cross section, is formed
6 is performed before punching. When such a groove is formed, the material in the vicinity of the groove is pushed out around the groove.
As a result, a distortion directed in the direction of arrow A is given in advance to the portion serving as the internal lead. On the other hand, when punching is performed without providing such a groove, the internal lead moves in the direction of arrow B.

[0010] Therefore, as described above, the distortion of the internal lead in the direction opposite to the direction of movement at the time of punching is applied to the internal lead in advance, thereby canceling the movement of the internal lead at the time of punching and, as a result, reducing the lead shift. The amount of distortion given in advance can be adjusted by the depth, width, etc. of the groove.

Incidentally, FIG. 1 shows a concave portion 12a in a conventional correction step.

Example 1 Next, an example using the manufacturing method of the present invention will be described. Using a 42-alloy alloy material with a thickness of 0.15 mm, the tip pitch of the inner lead
mm, a tip width of 0.13 mm, and a lead length of 13 mm, a cross section V having a depth of 80 μm and an angle of 60 ° is formed at a portion serving as a scrap at the root of an internal lead.
, And then internal leads were formed by punching. As a result, the deviation of the position of the lead tip was 0.07. In addition, as a result of forming the internal lead without forming the groove, the deviation of the leading end position of the lead was 0.125 mm. Therefore, when the groove is provided, the deviation of the lead tip position is reduced to about half.

[0013]

As described in detail above, the present invention provides
Since a groove is formed in advance in a portion where punching is to be performed, and the lead shift is canceled when the internal lead is formed later, it is possible to manufacture a lead frame with less lead shift and no damage to the internal lead.

[Brief description of the drawings]

FIG. 1 is a plan view showing an entire lead frame for a semiconductor device.

FIG. 2 is an enlarged plan view of an internal lead of the present invention.

FIG. 3 is a sectional view taken along lines 3-3 in FIG. 2;

FIG. 4 is an enlarged plan view showing an internal lead manufactured by a conventional method.

FIG. 5 is an enlarged plan view showing an internal lead subjected to a conventional repairing process.

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lead frame 12 Internal lead 14 Punched waste 16 Groove

Claims (2)

(57) [Claims] In a method of manufacturing a lead frame for a semiconductor device, before forming an internal lead in a punching step, a step of forming a groove in a root portion of the internal lead which becomes a scrap in a subsequent punching step; Forming a lead frame for a semiconductor device by removing a scrap portion by punching. 2. The method according to claim 1, wherein said groove has a V-shaped cross section.