JPH02198162A - Lead frame for semiconductor device and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a lead frame for semiconductor devices, and in particular is used to facilitate the assembly work of semiconductor devices. This is to prevent the lead frame from becoming two-piece when assembling a semiconductor device.

(Prior Art) FIG. 3 shows a cross-sectional shape of a convex portion of a lead frame for a semiconductor device formed by a conventional technique in a state where three lead frames 1 are stacked.

In other words, a plurality of lead frames are stacked during assembly, and in order to pick up each lead frame one by one, a gap is required between adjacent lead frames. Is required. Normally, these protrusions are formed by stamping or half punching in order to obtain a required height H relative to the plate thickness T of the lead frame. That is, with a punch having a diameter D1 of a press die (not shown),
A lead frame material with a thickness T is punched out (half punched) to form a protrusion 2 with a height H. At this time, the protrusion-forming punch diameter D and the die diameter D2 were approximately the same diameter. The gap C when lead frames are stacked is the protrusion height H
When the average distance was 0.4 mm, the average distance was 0.3 mm.

(Problem to be solved by the invention) ■) In the semiconductor lead frame 1 shown in FIG.
are arranged at six locations, but when the lead frames are stacked in the thickness direction as shown in Figure 3, the corners of the protrusions sag 3.
The lead frame fits into the hole (recess) 4 left by the protrusion forming punch, and even if you try to pick up one lead frame with a suction cup or nail, the lower one or two lead frames will fall at the same time. There was a problem in that the workpiece was picked up, causing an abnormality in the supply of workpieces to the semiconductor device assembly machine.

2) Furthermore, as the number of stacked lead frames increases, the weight of the lead frame increases, which causes the problem that the protrusions fit tightly together. Furthermore, the six protrusions rarely get stuck together, and even if you try to stack the lead frames horizontally to pick them up with a suction cup or claw, the bottom lead frame will not be horizontal due to the difference in how well they fit together. Even in this state, the top layer lead frames stacked up in tens of sheets have a slope that is greater than the thickness of the lead frame, causing problems such as being unable to be vacuum-sucked or gripped with nails.

3) Also, to prevent jamming, the convex diameter D2 is the hole diameter D1.
If it is made larger, the height of the protrusions becomes lower, and there is a drawback that the stacking gap C required for the claw to grip cannot satisfy the minimum standard value of 0.3 mm.

According to the present invention, when stacking lead frames horizontally during semiconductor device assembly work, each lead frame can be stacked horizontally one by one, and when one of the top layers is picked up, it is possible to reliably pick up one lead frame. The purpose is to make it similar.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a lead frame for a semiconductor device having a protrusion in the thickness direction of the lead frame, in which the diameter of the hole for forming the protrusion of the lead frame is This is a lead frame for a semiconductor device characterized by having a recess that is smaller in diameter than the protrusion and near the center of the protrusion. Further, the present invention provides a lead frame with a protrusion punched out in the thickness direction thereof, and a recess is provided near the center of the upper part of the protrusion to expand the diameter of the protrusion.
This method of manufacturing a lead frame for a semiconductor device is characterized in that the diameter of the protrusion is made larger than the diameter of the recess formed during the stamping and protrusion molding.

That is, the present invention prevents the lead frames from fitting into each other by enlarging the diameter of the protrusion using the recess provided at the center of the protrusion, thereby ensuring that each lead frame is fitted one by one. can be picked up with a claw or suction cup. In addition, by forming a diameter-enlarging recess in the center of the protrusion and at the same time using punching, the height of the protrusion can be press-formed with high precision. The protrusions of the lead frame can be held horizontally in a well-balanced manner, and the standard value of the gap between the lead frames can be maintained with high precision.

(Example) An example of the present invention will be described below with reference to the drawings. 1st
The figure is a cross-sectional view showing the stacked state of the lead frame at the protrusion part of the same embodiment, and FIG. 2 is a cross-sectional view of the mold part showing the concave part for forming the protrusion of the lead frame. Since this is an example corresponding to the conventional example, the same reference numerals are used for corresponding parts. The feature here is that the diameter d of the recess 4 for forming the protrusion on the lead frame 1 is the same as the diameter d2 of the protrusion 2 and dl.
In order to maintain this relationship, a recess 11 is provided near the center of the protrusion.

Next, referring to FIG. 2, an example of how to make the lead frame shown in FIG. 1 will be explained. The lead frame material 1 is supplied onto the upper surface of the die (convex side of the protrusion forming tool) 21, and the material 1 is strongly pressed against the die 21 by the stripper (concave side of the protrusion forming tool) 22, and the protrusion forming punch 23 is applied. push upward. Next, the protrusion enlarging punch 24 is pushed down from above and pressurized until it comes into close contact with the inner diameter d2 of the stripper 22.

The diameter of this d is set to be larger than the convexity forming punch diameter d1. In the example, dl-1, 2m+w, d2" 1
．． 5m+*, and if the push-up amount h2 of the punch 23 is made too large in order to increase the protrusion height h3,
Because the lead frame material 1 and the protrusion 2□ break, when the plate thickness is t-0.6 mm, the punch is pushed up m h
2-0, 4 m+s. Also, punch 2 for enlarging protrusions
4, the tip R and the angle θ are based on the inner diameter d of the lead frame material 1.
2, the R-0,25 angle, θ-60'', and the pushing depth were set to -0,45 inch, so that the height of the protrusion h3 was stabilized by pushing it in enough.As a result. The height of the protrusion 63 was 0.44±0.02 mm, and the minimum standard value of the gap C of 0.3 mm was sufficiently secured.

If you do it as shown in Figures 1 and 2, ■) The diameter of the protrusion is sufficiently expanded using the protrusion enlarging punch, so that when the lead frames are stacked, the protrusions 2 and 2 will fit into the recesses 4. It could have been prevented.

2) By being able to accurately form the height dimension of the protrusion,
There is little variation in the protrusions 1 at six locations, and when the lead frames are stacked, they can be kept in a horizontal state that is easy to grip with a suction cup or a claw, and the gap C between the lead frames can be maintained at a standard value.

3) The operating rate of the semiconductor device assembly machine is the same as 1) above.

Due to the effect of 2), it improved by 5%.

4) In addition, in the cleaning process after pressing the semiconductor lead frame, since the lead frame does not come into close contact with each other due to the protrusions, the cleaning liquid sufficiently hits the lead frame surface, resulting in the additional effect that the lead frame can be cleaned well.

[Effects of the Invention] As explained above, according to the present invention, lead frames can be stacked horizontally during assembly of semiconductor devices, and one of the top layers can be reliably picked up. It is something that you have.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a stacked state of essential parts of an embodiment of the present invention, FIG. 2 is a cross-sectional view of the process of obtaining the same embodiment, and FIG. 3 is a cross-sectional view showing a stacked state of conventional lead frames. , 4th
Figure (a) is a plan view of the lead frame, and figure (b) is a side view of the lead frame. 1...Lead frame, 2□...Protrusion, 4,11.
...dent, 21...die, 22...stripper
23... Punch for forming protrusions, 24... Punch for enlarging protrusions. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3 (a) (b) Figure 2 Figure 4

Claims (2)

[Claims] (1) In a lead frame for a semiconductor device having a protrusion in the thickness direction of the lead frame, the diameter of the hole for forming the protrusion in the lead frame is smaller than the diameter of the protrusion, and the protrusion has a recess near the center thereof. A lead frame for semiconductor devices characterized by the following. (2) Providing a punched convexity in the thickness direction of the lead frame, providing a recess near the center of the upper part of this convexity to push out the diameter of the convexity, and forming this convex diameter during the punching convexity forming process. A method for manufacturing a lead frame for a semiconductor device, characterized in that the diameter of the lead frame is larger than that of a recess.