JPH05315515A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device in which a lead frame having no tie-bar is used. CONSTITUTION:Tie-bars are removed from the part between the inner edge 2b and the outer edge 2a of the adjacently located leads 2, and the remaining of cutting margin of the tie-bars is prevented. Besides, a part (dam barrier 1) of sealing resin is allowed to flow out to the outer edge 2a of the adjacent lead 2, and the dam barr 1 can be removed by a laser beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device using a lead frame without a tie bar.

[0002]

2. Description of the Related Art In a conventional semiconductor device, a semiconductor element mounted on an island of a lead frame 7 is sealed by a resin sealing portion 8 as shown in FIG. Adjacent lead 2 to prevent
The lead frame 7 having a structure in which the tie bars 5 are provided so as to be suspended from each other is used, and the excess resin that has flowed out to the tie bar 5 portion together with the tie bars 5 after resin sealing is cut and removed by a mold.

FIG. 7 is a diagram showing a state of the semiconductor device after cutting the tie bar. When the resin is sealed, the tie bar 5 exists at the position shown by the dotted line, and when the tie bar 5 is cut,
On both side edges of the lead 2, a cutting margin 6 is left overhanging in the lateral direction.

After cutting the tie bar, a resin (hereinafter, referred to as a thin burr) slightly flowing out onto the lead and a resin residue are removed by honing and solder plating is applied, and then the outer edge 2a of the lead 2 is connected to the lead. The semiconductor device is cut off from the frame 7 and the outer edge 2a of each lead is separately and independently cut off to undergo a process such as lead molding. FIG. 8 shows the state of the leads of the semiconductor device after the lead molding, but the tie bar cutting margin 6 remains in a form that travels more than the width of the lead 2.

[0005]

In the manufacturing of this conventional semiconductor device, a die is used to cut and remove the tie bar. As the pitch is reduced, it is becoming difficult to manufacture a die for cutting the tie bar.

Further, when a die is applied, it is worn quickly and requires a lot of man-hours for maintenance. Furthermore, even if the tie bar is cut, the dam burr is not reliably removed and the resin is unstable, and the resin flows to the next lead molding process, and the resin falls off during lead molding, causing dents on the leads. was there. In addition, in the case of cutting the tie bar with a mold, it is necessary to prepare a mold for each package, which requires a lot of man-hours for managing and maintaining the mold.

Further, since the tie bar cutting margin 6 remains as shown in FIG. 8 after the tie bar cutting, the strength of the lead 2 at the tie bar portion becomes larger than that of the other portions, and the bending of the lead is constant during lead molding. There was a problem that disappeared.

An object of the present invention is to provide a semiconductor device using a lead frame having no tie bar.

[0009]

In order to achieve the above object, a semiconductor device according to the present invention is a semiconductor device in which a semiconductor element mounted on an island of a lead frame is sealed with resin. The frame has a plurality of leads that are electrically connected to the electrodes of the semiconductor element on the island. The plurality of leads have outer edges integrated with the lead frame, and adjacent leads are independent of each other. The leads are formed into a comb-tooth shape that is cut off, and the plurality of comb-tooth-shaped leads extend to positions where the inner edge approaches the outer edge of the island of the lead frame.

[0010]

The tie bar is eliminated between the inner edge and the outer edge of the adjacent leads to prevent the tie bar cutting margin from remaining.

Further, a part of the sealing resin is allowed to flow to the outer edge of the adjacent lead, and the resin between the leads is removed by laser light.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings by taking a QFP package as an example.

FIG. 1 is a diagram showing a QFP package type semiconductor device according to an embodiment of the present invention, and FIG. 2 is a QFP package type device in which the outer edges of the leads are cut off from the lead frame and the leads are bent and formed in the present invention. FIG. 3 is a perspective view showing a state where the semiconductor device is completed, and FIG. 3 is a diagram showing a lead shape after the completion.

In the figure, this embodiment is a semiconductor device in which a semiconductor element mounted on an island of a lead frame 7 is sealed with a resin sealing portion 8.

The lead frame 7 has a plurality of leads 2 and 2 electrically connected to the electrodes of the semiconductor element on the island.
…have.

Outer edges 2a of the plurality of leads 2 are formed integrally with the lead frame 7 and are formed in a comb shape in which adjacent ones are separated from each other independently.

The plurality of leads 2 having a comb-like shape are formed on the inner end edge 2.
b extends to a position approaching the outer edge of the island of the lead frame 7.

In this embodiment, since there is no tie bar, the resin 1 (hereinafter referred to as dam burr) that has flown out during resin sealing reaches the outer edge 2a of the lead 2 through the space between the adjacent leads 2.

Next, FIG. 4 is a diagram showing the manner of dam burr cutting and removal by the laser of the present invention. The laser beam 3 is narrowed down to about 50 μm, and the laser beam scanning speed is about 500 mm / s from the inner edge 2b of the lead 2 (or from the outer edge 2a of the lead 2) along the dam burr 1 to the outer edge 2a of the lead 2 ( Alternatively, up to the inner end edge 2b of the lead 2) is scanned by a scanning path such as 3a and 3b in FIG. 4 by a galvano mirror, a polygon mirror or the like (not shown), and the dam burr 1 is sequentially burned out.

After scanning to the lead end to burn out the dam burr 1, the next scan is performed again from the lead end so as to overlap the scanned range burned to the previous extent to some extent, and the resin between the leads is burned out. These scans are sequentially performed for each lead to remove dam burrs between all the leads of the semiconductor device.

In the lead frame from which the dam burrs have been removed, the resin (hereinafter referred to as thin burrs) slightly flowing out onto the leads and the resin residue are removed by honing as in the conventional case, and solder plating is performed. Then, the semiconductor device shown in FIGS. 2 and 3 is obtained through steps such as lead cutting and lead forming.

FIG. 5 is a diagram showing a state of dam burr cutting and removal by a laser according to another embodiment of the present invention. First, the laser beam is set larger than in the above-described embodiment, only the resin is burned off, and the output is set so as not to affect the lead portion.

Laser beam 3 for burning out only this resin
Is scanned on all surfaces on which lead and dam burrs are present on the resin-sealed lead frame in a scanning path such as 4a and 4b in the same manner as in the above-described embodiment, so that it slightly leaks onto the dam burrs and leads. The resin (hereinafter, referred to as thin burr) can be burned out. After removing the dam burr, the semiconductor device is completed through the same steps as conventional ones.

[0024]

As described above, according to the present invention, the lead frame having no tie bar is used. Therefore, by removing the dam burr by the laser, the lead pitch is narrower than the cutting and removal of the tie bar and the dam burr by the mold. It can also be applied to semiconductor devices, and also eliminates the need for maintenance due to die wear.

Further, since it is possible to cope with the type change by simply changing the laser irradiation position according to the data, it is not necessary to replace the mold each time the type is changed, unlike the conventional case.
The setup time can be greatly reduced.

If the scanning method shown in FIG. 5 is used,
This makes it possible to handle high-speed and easy switching of product types. Further, since there is no tie bar cutting margin in the lead forming process, the bending strength is constant throughout the lead, and the forming can be performed easily and accurately.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a completed state of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a lead shape after completion.

FIG. 4 is a diagram showing a state of dam burr cutting and removal by the laser of the present invention.

FIG. 5 is a diagram showing how dam burrs are cut and removed by the laser of the present invention.

FIG. 6 is a diagram showing a conventional semiconductor device.

FIG. 7 is a view showing a conventional tie bar cutting removal state.

FIG. 8 is a view showing a conventional lead shape after completion.

[Explanation of symbols]

 1 dam burr 2 lead 2a outer edge of lead 2b inner edge of lead 7 lead frame 8 resin sealing part

Claims (1)

[Claims] 1. A semiconductor device in which a semiconductor element mounted on an island of a lead frame is sealed with resin, wherein the lead frame has a plurality of electrodes electrically connected to electrodes of the semiconductor element on the island. The plurality of leads are formed in a comb-teeth shape in which outer edges are integrated with the lead frame and adjacent ones are separated from each other independently and independently. A semiconductor device, wherein the plurality of leads extend to a position where an inner edge approaches an outer edge of an island of a lead frame.