JPH0695560B2 - Lead frame for semiconductor device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a lead frame for a semiconductor device, and is particularly used for facilitating the assembly work of the semiconductor device. The purpose of the present invention is to prevent the two lead frames from overlapping when assembling the semiconductor device.

(Prior Art) A cross-sectional shape of a raised portion of a semiconductor device lead frame formed by the prior art is shown in FIG. 3 in a state where three lead frames 1 are stacked.

That is, a plurality of lead frames are stacked at the time of assembly work, and a gap is required between adjacent lead frames in order to pick up one by one after that, but in order to form this gap, a protrusion 2 is formed on the lead frame surface. Is required. Usually, this protrusion is formed by stamping (half blanking) to obtain a required height H with respect to the plate thickness T of the lead frame. That is, a lead frame material having a material thickness T is punched (semi-blanking) with a punch (not shown) having a diameter D ₁ to form a protrusion 2 having a height H. At this time, the punch forming punch diameter D ₁ and the die diameter D ₂ were substantially the same. The gap C when the lead frames are stacked is the average of the protrusion heights H.
When it was 0.4 mm, the average was 0.3 mm.

(Problems to be Solved by the Invention) 1) In the semiconductor lead frame 1 shown in FIG.
There are 6 corners, but when the lead frames are stacked in the plate thickness direction as shown in FIG.
Fits into the hole (concave) 4 of the protrusion forming punch, and even if one lead frame is to be picked up by a suction cup or a claw, the lower one or two sheets are simultaneously There was a problem in that the workpieces were picked up and the work supply of the semiconductor device assembling machine was abnormal.

2) Further, the larger the number of stacked sheets, the larger the weight of the lead frame becomes. Furthermore, the protrusions are unlikely to fit in six joints, so even if you try to stack the lead frames horizontally to pick them up with suction cups or claws, the bottom lead frame will be flat due to the difference in the fit. Even in the state, the dozens of stacked uppermost lead frames had a problem that they could not be attracted by vacuum and could not be gripped by the claws because of the inclination more than the thickness of the lead frame.

3) If the protrusion diameter D ₂ is made larger than the hole diameter D ₁ to prevent fitting, the protrusion height becomes lower, and the stacking gap C required for gripping by the claw satisfies the standard value 0.3 mm minimum. There was a flaw that I could not do.

INDUSTRIAL APPLICABILITY According to the present invention, when the lead frames are stacked horizontally during the assembly work of the semiconductor device, each of the lead frames can be stacked horizontally, and when the top layer is picked up, one piece can be reliably picked up. The purpose is to

[Structure of the Invention] (Means and Actions for Solving the Problems) The present invention relates to a lead frame for a semiconductor device having a protrusion in the plate thickness direction of the lead frame, wherein the lead forming hole diameter of the lead frame is A lead frame for a semiconductor device, which is smaller than the diameter of the protrusion and has a recess near the center of the protrusion. Further, the present invention, the lead frame, provided with a protrusion in the plate thickness direction, a recess is provided in the vicinity of the center of the upper portion of the protrusion to spread the protrusion diameter,
The method for manufacturing a lead frame for a semiconductor device is characterized in that the diameter of the protrusion is set to be larger than the diameter of the recess formed at the time of the stamping and protrusion molding.

That is, according to the present invention, the fitting of the lead frame is enlarged by the recess provided at the center of the protruding portion to prevent the fitting of the lead frame to the recess for forming the protruding portion, and the lead frame is securely attached one by one. Can be picked up with a nail or a suction cup. In addition, by forming a dent for enlarging the diameter in the central portion of the protrusion and using a stamping process, the height of the protrusion can be accurately formed under pressure. The protrusions of the lead frame allow the lead frame to be held horizontally, and the standard value of the gap between the lead frames can be secured accurately.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 2 is a cross-sectional view showing a stacking state at the raised portions of the lead frame of the same embodiment, and FIG. 2 is a cross-sectional view of a die portion showing a state of formation of the raised portions of the lead frame. Since this is an example of a case corresponding to the above-mentioned conventional example, the same reference numerals are used for corresponding portions. The feature here is the lead frame 1
Diameter d ₁ of the recess for the protrusion forming 4 is in the relationship of the projections 2 ₁ diameter d ₂ and d ₁ <d _2, in order to have this relationship, that it has a recess 11 in the vicinity of the protrusion center is there.

Next, referring to FIG. 2, an example of how to make the lead frame shown in FIG. 1 will be described. The lead frame material 1 is supplied to the upper surface of the die (convex side of the convex forming tool) 21, and the material forming 1 is strongly pressed against the die 21 by the stripper (concave side of the convex forming tool) 22. Push upwards. Next, the punch 24 for enlarging enlargement is pushed down from the upper side and pressed until it comes into close contact with the inner diameter d _{2 of the} stripper 22. The diameter of d ₂ is set to be larger than the diameter of the protrusion forming punch d ₁ . In the embodiment, d ₁ = 1.2 mm, d ₂ = 1.5 mm, and if the push-up amount h ₂ of the punch 23 is too large in order to increase the protrusion height h ₃ , the lead frame material 1 and the protrusion 2 are increased. _{Since 1} and will be broken, when the plate thickness t = 0.6 mm, the punch pushing amount h ₂ =
It was 0.4 mm. Further, the tip R and the angle θ of the protrusion enlarging punch 24 are set to R = 0.25 mm, θ = 60 °, and the indentation depth h ₁ = 0.45 mm so that the lead frame material 1 can be easily adhered to the inner diameter d _2. It was pushed in so that the dimension of the protrusion height h ₃ became stable. As a result, the convex height h ₃ dimension is 0.44 ± 0.02 mm,
The standard value of the clearance C, 0.3mm, could be sufficiently secured.

Figure 1, if as in the Fig. 2, 1) to spread sufficiently press the convex Okoshi径in protrusion expanding punch, be mate to TokitotsuOkoshi 2 ₁ dent 4 stacked lead frame I was able to prevent it.

2) Due to the fact that the dimension in the height direction of protrusion can be accurately formed,
There is little variation in the protrusions 1 at the six places, and when the lead frames are stacked, it is possible to maintain a horizontal state in which the suction cups or the claws can easily grasp, and it is possible to maintain the lead frame gap C at the standard value.

3) The operating rate of the semiconductor device assembly machine was improved by 5% due to the effects of 1) and 2) above.

4) Further, in the cleaning process after the semiconductor lead frame is pressed, the lead frame does not come into close contact with each other due to the protrusion, so that there is an attendant effect that the cleaning liquid sufficiently contacts the surface of the lead frame and can be cleaned well.

[Effects of the Invention] As described above, according to the present invention, it is possible to stack the lead frames horizontally during the assembling work of the semiconductor device and surely pick up one of the uppermost layers. I have.

[Brief description of drawings]

FIG. 1 is a sectional view showing a stacked state of an essential part of an embodiment of the present invention, FIG. 2 is a sectional view of a step of obtaining the same embodiment, and FIG. 3 is a sectional view showing a stacked state of a conventional lead frame. , 4th
FIG. 1A is a plan view of the lead frame, and FIG. 1B is a side view thereof. 1 ... lead frame, 2 ₁ ... protrusion, 4,11 ... recess, 21 ... die, 22 ... stripper, 23 ... protrusion forming punch, 24 ... protrusion expanding punch.

Claims (2)

[Claims] 1. A lead frame for a semiconductor device having a protrusion in a plate thickness direction of a lead frame, wherein a diameter of a protrusion forming hole of the lead frame is smaller than a diameter of the protrusion, and a recess is formed near a center of the protrusion. A lead frame for a semiconductor device, comprising: 2. A lead frame is provided with a protrusion in the plate thickness direction, a recess is provided in the vicinity of the center of the upper portion of the protrusion to widen the protrusion diameter, and the protrusion diameter is used to form the protrusion protrusion. A method for manufacturing a lead frame for a semiconductor device, characterized in that the diameter is larger than the diameter of a recess that is sometimes formed.