JPH04286355A - Lead frame - Google Patents

Abstract

PURPOSE:To enable resin, which is high in adhesive power to a lead frame and hard to remove from a runner in a semiconductor mounting resin sealed package assembly process, to be easily separated from the runner so as to protect the package against troubles which occur when resin is partially removed. CONSTITUTION:A through-hole 1 is provided to the runner of a lead frame 4, and a runner 2 is easily separated from the lead frame by pushing up a movable pin 5 from below through the through-hole when the runner 2 is separated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame used in a resin-sealed package for mounting a semiconductor.

0002

2. Description of the Related Art A product immediately after the sealing process is composed of three parts. As shown in FIG. 2, each part is a package part, a lead frame part, and a resin injection path (runner) part. The runner passes along an arbitrary path on the lead frame and always comes into close contact with the lead frame. Also,
The runner is connected to the package at the gate and must be removed in a subsequent process. Conventionally, the runner part was separated from the lead frame at the same time as the gate was cut with a cutter.

0003

[Problems to be Solved by the Invention] In resin-sealed packages, the lead frame is sealed with a resin such as epoxy, but the injected resin plays an important role in protecting the semiconductor device from the external environment. Therefore, close contact with the lead frame is important. The resin material injected into the mold passes through a runner on the lead frame and flows into the mold cavity through the gate hole. After filling, the resin hardens, and at the same time, the resin remaining inside the runner also hardens and adheres tightly to the lead frame. During the package assembly process, the resin remaining in the runner must be removed. However, recent resin materials tend to have low stress and high adhesion, and removal of these materials poses several problems. That is, the runner strongly adheres to the lead frame and is not easily peeled off using the conventional gate cutting method. If you try to remove it forcibly, the lead frame will be deformed, and sometimes burrs will remain at the gate cut portion. A particular problem arises when the resin in the runner is not sufficiently removed, resulting in problems such as breakage and abrasion of the processing mold for lead cutting and lead bending after gate cutting. The present invention solves the above problems and aims to provide a lead frame from which the runner can be sufficiently removed.

0004

SUMMARY OF THE INVENTION To achieve this object, the lead frame of the present invention has a through hole in the runner section near the gate. Furthermore, by utilizing this through hole, a movable pin is used to push up the runner from below the lead frame during gate cutting, thereby peeling the runner from the lead frame.

[0005]

[Function] The above structure reduces the adhesion area between the lead frame and runner resin, lowers the adhesion force, and improves the peelability.The structure and method of directly applying force to the runner from the through hole makes it easy to peel off the runner. can be realized.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a plan view of a conventionally used lead frame. FIG. 1 shows a lead frame used in the present invention. The through hole 1 seen in FIG. 1 coincides with the runner position. Figure 2 shows the state of the runner, and Figure 1
This corresponds to the through hole 1 of . FIG. 3 shows the action of the movable pin 5 for runner stripping of the first embodiment. By fixing the lead frame 4 and the package part 3 and pushing the movable pin 5 up from the through hole 1, the runner 2 and At the same time as the lead frame 4 is peeled off, the gate portion is cut, and gate cutting is performed.

FIG. 4 shows a second embodiment, in which a cutter 6 is used to cut the gate portion, and a movable pin 5 is pushed up from the through hole 1 to cut the gate. Although the boundary between the package and the runner is shaped to be easy to cut, this method is effective in improving the shape of the cut surface of the gate portion and preventing burrs from remaining.

[0008]

As described above, according to this embodiment, the movable pin can be pushed up using the through hole in the lead frame runner part to effectively peel off the resin that has adhered to the resin material with improved adhesive strength. It is effective for

[Brief explanation of the drawing]

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

[Fig. 2] A plan view of the lead frame of the present invention showing the shape of the runner after resin injection.

[Figure 3] Processing diagram showing an example of runner peeling using the lead frame of the present invention

[Fig. 4] Processing diagram showing a second example of runner peeling using the lead frame of the present invention.

[Figure 5] Plan view of conventional lead frame

[Explanation of symbols]

1 Through hole 2 Runner 3 Package 4 Lead frame 5 Movable pin 6 Cutter

Claims (1)

[Claims] 1. A lead frame, wherein the lead frame has a through hole in contact with a resin injection path formed on the lead frame in an assembly process of a resin-sealed package for mounting a semiconductor.