JP3052986B2 - Lead frame film pasting 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 film sticking device for a lead frame, and more particularly to a film sticking device capable of preventing burrs from occurring at a film punching stage before sticking.

[0002]

2. Description of the Related Art In a lead frame on which an IC or LSI is mounted, a film cut into a strip shape is generally adhered to the lead end of the lead frame in order to prevent a step or shift at the lead end. Yes, and LOC
In a (lead-on-chip) type, a lead and a chip are often attached.

Conventionally, an apparatus as shown in FIG. 4 has been used for attaching such a film. This device comprises a punch 2 lowered by an air cylinder 1.
And a die 3 on which a film 6 to be punched is mounted, and a heat plate 5 on which a lead frame 7 is mounted and which is disposed below. The film 6 is punched into a predetermined shape by the lowering of the punch 2. At the same time that the film 6 is supplied onto the lead frame 7, the punched film 6 is pressed against the lead frame 7 and thermocompression-bonded.

[0004]

However, in this type of sticking apparatus, the film 6 is punched by applying a shearing force between the tip 11 of the punch 2 and the upper part 12 of the die 3. Therefore, the film 6 receives a large compressive stress from the punch 2 and the die 3 at the time of punching. As a result, the punch 6 and the die 3 shown in FIG.
As shown in the enlarged view of FIG. 5, the large compressive stress generates cracks 9 in the cut-out portion of the film 6, which causes burrs such as elongated thread burrs and minute chips in the cut portion. Sometimes. Affixing the film with such burrs to the lead frame leads to scattered burrs adhering to the fine lead surface of the lead frame, resulting in an extremely large defect such as bonding failure. .

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a film sticking apparatus in which burrs are not generated on a punched film, so that burrs do not adhere to lead portions of a lead frame.

[0006]

[Means for Solving the Problems]

According to the present invention, in order to prevent burrs from being generated on a punched film, a buffer layer is provided on the surface of a die, and the film is placed on the buffer layer and punched out. Is provided.

[0008]

The buffer layer provided on the surface of the die relieves the compressive stress acting on the film at the time of punching, increases the tensile stress, and prevents the occurrence of cracks at the cut and cut portion of the film.

[0009]

FIG. 1 shows an apparatus for attaching a film to a lead frame according to an embodiment of the present invention. The apparatus comprises a punch 2 lowered by an air cylinder 1, a die 3 paired with the punch 2, a buffer layer 4 made of aluminum provided on the surface of the die 3 and having the same shape as the punched shape of the die 3. , A heat plate 5 disposed below the die 3, a film 6 to be punched on the buffer layer 4, and a lead frame 7 on the heat plate 5.

FIG. 2 is an enlarged view of the punch and die of another embodiment, and differs from the embodiment of FIG. 1 in that the edge 8 of the buffer layer 4 is formed in an arc shape. This arc shape is more effective and practical in the sense that the compressive stress acting on the film 6 at the time of punching is more smoothly alleviated.
It has been discovered in the course of the present invention that this arc shape is formed automatically by mounting the material constituting the buffer layer 4 on the die 3 and punching it out with the punch 2, but from the beginning it is made in this way. May be. As the material of the buffer layer 4, a non-ferrous metal such as aluminum or brass, or an elastic body such as hard rubber is used. Further, the same material as the film 6 generally made of a rigid resin is attached to the surface of the die 3. What is punched by the punch 2 can be used as it is as the buffer layer 4. It is of course conceivable to form the buffer layer 4 by coating with a paint.

The thickness of the film 6 is, for example, 30 to 100.
The thickness of the buffer layer 4 is preferably in the range of 1/5 to 5 times the thickness of the film 6, and below this, the effect of the buffer layer becomes difficult to obtain, and conversely, When it exceeds, variation in dimensions of the punched film is likely to occur.

In this apparatus, when the punch 2 is lowered by the operation of the air cylinder 1, the lowered punch 2 punches the film 6 placed on the buffer layer 4 on the surface of the die 3, and further releases the punched film 6. It is supplied onto a lead frame 7 placed on a heat plate 5. Then, the supplied film 6 is pressed by the punch 22 and is thermocompression-bonded to the lead frame 7 and attached.

In the above operation, as shown in FIG.
The presence of the buffer layer 4 reduces the compressive stress and increases the tensile stress, so that cracks do not occur.

[0014]

As described above, according to the film sticking apparatus of the present invention, since the buffer layer is provided on the surface of the die, the compressive stress applied to the film from the punch and the die can reduce the buffer stress. The layer is alleviated, and as a result, the occurrence of cracks at the cut and cut portions of the film due to excessive compressive stress, the occurrence of burrs due to this, and the bonding failure caused by this are prevented beforehand can do.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing another embodiment of the present invention.

FIG. 3 is a partially enlarged view showing the operation of the present invention.

FIG. 4 is a sectional view showing a conventional film sticking apparatus.

FIG. 5 is an enlarged cross-sectional view of a punching punch portion and a die portion in a conventional film sticking apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air cylinder 2 Punch 3 Die 4 Buffer layer 5 Heat plate 6 Film 7 Lead frame 8 Edge

Continuation of the front page (72) Inventor Ryuji Yonemoto 3550 Kida Yomachi, Tsuchiura-shi, Ibaraki Hitachi Systems, Ltd. System Materials Research Laboratories (56) References JP-A-4-196576 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/50 B26F 1/00-3/16 B21D 28/00

Claims (5)

(57) [Claims] 1. A film sticking apparatus for punching a film placed on a surface of a die into a predetermined shape by a punch, and sticking the punched film to a lower lead frame. A film sticking apparatus for a lead frame, wherein a layer is provided, a film is placed on the layer, and punching is performed. 2. An apparatus according to claim 1, wherein said buffer layer has an arc-shaped edge. 3. The apparatus according to claim 1, wherein said buffer layer has a thickness in the range of 1/5 to 5 times the thickness of the film to be punched. 4. The apparatus according to claim 1, wherein said buffer layer is made of a non-ferrous metal such as aluminum or brass. 5. The apparatus according to claim 1, wherein said buffer layer is made of an elastic material such as hard rubber.