JP3065211B2 - Lead frame depressing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame depressing apparatus.

[0002]

2. Description of the Related Art A lead frame used for manufacturing a semiconductor device is composed of an inner lead, an outer lead, a tie bar, a pad for mounting an element, a support bar, and the like. Noble metal plating is performed on the tips and pads. At this time, in order for the upper surface of the semiconductor chip mounted on the pad in the mounted state and the tip of the inner lead connected thereto to be located on the same plane, the support bar is pushed and bent to raise the pad by a predetermined height. Depressing for displacing downward is performed.

[0003] Usually, a depress presses a predetermined portion of a support bar using a die. The depress die includes an upper die provided with a bending punch and a lower die having an opening corresponding to the amount of bending. And a support block disposed in the lower mold and urged in the direction of the bending punch.

[0004]

However, when depressing the pad using the mold according to the conventional example, the punch moves so that the punch and the support block are parallel to each other. When dimple processing is performed on the pad or when the pad has a plate thickness deviation, the pad may be deformed or the support bar may be bent unevenly. Further, in a unit frame in which a plurality of lead frames are continuously formed, when a plurality of pads are simultaneously depressed, it is difficult to depress each pad uniformly, and it is said that there is some variation. There was a problem.

Furthermore, since the depressing step is the final step of the lead frame manufacturing step, if a defect occurs here, not only the loss of material but also the steps up to that point are wasted, resulting in extremely serious loss. There was a problem of becoming. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lead frame depressing device that can prevent pad deformation and can perform uniform bending.

[0006]

According to the present invention, there is provided a semiconductor device comprising:
The lead frame depressing device described above is composed of an upper die and a lower die, and presses down a support bar of the lead frame to a predetermined position to displace a pad supported by the support bar downward. And a depress punch disposed on the upper die for bending a support bar into a desired shape, and a depress punch disposed on the lower die with a small gap, and paired with the depress punch. The apparatus includes a support block, a self-centering support member that supports the support block so as to be able to swing and move up and down, and a biasing unit that presses the support block in a depressing punch direction.

[0007]

In the depressing device for a lead frame according to the first aspect, the support block disposed in the lower mold is attached to the self-aligning support member so as to be able to swing up and down freely and to be supported by the urging means. Since the block is urged in the direction of the depress punch, even if there is dimple processing on the back surface of the pad of the lead frame or even if the block has a thickness deviation, the depress punch and the lead pressed from the top According to the thickness of the frame, the support block is inclined so that a load is applied to the pad substantially evenly. Accordingly, the pad and the support bar are not unduly deformed, and a uniform bending process is performed.

[0008]

EXAMPLES Next, examples embodying the present invention will be described to provide an understanding of the present invention. FIG. 1 is a cross-sectional view of a lead frame depressing apparatus according to an embodiment of the present invention.

As shown in FIG. 1, a lead frame depressing apparatus 10 according to one embodiment of the present invention includes a depressing punch 11 mounted on an upper die (not shown) and a lower die 12.
And a self-aligning roller bearing 14 which is an example of a self-aligning support member that supports the lower part of the support block 13 so as to swing and move up and down. Four equally arranged springs 15 for urging the support block 13 upward, and an example of the urging means;
3 and an air cylinder 16 mounted on the bottom.

Here, the air cylinder 16 is connected to the compressed air system and urges the pressing force of the spring 15 from below. In this case, the press fitting 17 at the tip of the air cylinder 16 and the bottom surface of the support block 13 are in contact with each other in a spherical state. The support block 13 is attached to the lower mold 12 in a loose fit state with a gap, and the lower part is supported by a self-aligning roller bearing 14 so as to be able to swing freely, and can swing its head in a minute angle range. .

The support block 13 is slidably mounted on the inner ring 18 of the self-aligning roller bearing 14, and four springs 15 are provided in the middle of the support block 13. The upper surface of the lower mold 12 and the surface of the support block 13 are generally substantially flush with each other. When the operation of the upper depress punch 11 is completed and the depress punch 11 is lifted, the bent lead frame is pushed up. In addition to the depress punch 11, a stripper and a punch holder (not shown) are attached to the upper die.

Next, a method of forming a lead frame by using the lead frame depressing apparatus 10 will be described. First, while forming the inner lead, outer lead, tie bar, pilot hole, pad and support bar of the desired shape on the strip material mainly composed of copper,
Dimple processing and the like are performed as necessary, and precious metal plating is performed as necessary.

When the lead frame 19 is mounted at a predetermined position using the pilot hole of the lower die 12 from the strip-shaped material thus processed, when the depress punch 11 is lowered, the support bar portion is bent, The pad is pushed down a predetermined distance. In this case, even if dimple processing is formed on the pad, or even if the thickness of the pad is somewhat uneven, since the lower support block 13 can swing and can move up and down, the lead frame It can respond freely according to the shape of 19.

In this way, inconveniences such as deformation of the pad and uneven bending of the support bar due to the unilateral pressing force of the depress punch can be prevented, and highly reliable depress processing can be performed. Become. Also,
When depressing multiple pads in one process,
Although there is a processing difference between the center and both ends, the support block 13 freely moves up and down and swings according to each pad so that uniform depressing is possible. Thereafter, when the depress punch 11 is raised, the support block 13 is raised, and the bent lead frame 1 is bent.
9 is taken out. If necessary, the air cylinder 16 is further operated to perform knockout.

In the above embodiment, if necessary, the air cylinder 16 can be further vacuum-sucked. In this case, the press fitting 17 is a hook fitting which is hooked to the support block 13. The air cylinder 16 may be omitted by appropriately adjusting the spring 15.

[0016]

According to the first aspect of the present invention, since the support block disposed in the lower mold can be swung freely, it abuts according to the shape of the pad. The pad can be prevented from being deformed, and the support bar can be uniformly bent.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lead frame depressing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Depress device of lead frame 11 Depress punch 12 Lower die 13 Support block 14 Self-aligning roller bearing 15 Spring 16 Air cylinder 17 Press fitting 18 Inner ring 19 Lead frame

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-58261 (JP, A) JP-A 55-66022 (JP, U) JP-A 5-53789 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) B21D 45 / 04,5 / 01 B30B 15/02 H01L 23/50

Claims (1)

(57) [Claims] 1. A depressing device comprising an upper die and a lower die, for depressing a support bar of a lead frame to a predetermined position to displace a pad supported by the support bar downward, A depressing punch disposed on the upper die to bend the support bar into a desired shape; a support block disposed on the lower die with a small gap, and a pair with the depressing punch; A lead frame depressing device, comprising: a self-aligning support member that supports a support block so as to be able to swing and move up and down; and a biasing unit that presses the support block in a depressing punch direction.