JPH05235235A - Lead frame - Google Patents

Abstract

PURPOSE:To simply and effectively separate and remove slag from a lead frame by forming a cutout at a place corresponding to a runner through which melted resin for molding a semiconductor chip passes. CONSTITUTION:A slitlike cutout 6 is formed at a place corresponding to a runner 17 through which melted resin for molding a semiconductor chip of a lead frame 1 passes. After a molded form is formed, before punching of a lead 3 by a punching unit, slag cured in the runner 17 must be separated from the frame 1. Since a cured position of the slag is at the cutout 6, the slag does not adhere to the frame 1 at all or adheres thereto partly weakly, and hence can be simply separated from the frame 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame,
More specifically, the present invention relates to a lead frame structure capable of easily separating resin residue, which has been cured in a runner, from the lead frame when forming a mold body for molding a semiconductor chip mounted on the lead frame.

[0002]

2. Description of the Related Art For electronic parts such as ICs and LSIs, a semiconductor chip cut out from a wafer is mounted on a land of a lead frame, and then a lead of the lead frame and an electrode of the semiconductor chip are connected by a wire, followed by resin molding. It is manufactured by forming a mold body for molding a semiconductor chip by an apparatus and punching the leads of a lead frame by a punching apparatus.

Molding of a molded body by a resin molding device is
This is done as follows. After sealing the lead frame between the upper mold and the lower mold, the molten resin heated and melted by the heater is pressure-fed to the lead frame side through the runner formed in the lower mold to surround the semiconductor chip (cavity). Called). Next, after the molten resin is cured, the upper mold and the lower mold are opened, and the lead frame on the lower mold is taken out.

The mold body is molded as described above, but the lead frame taken out from the lower mold has the residue of resin (called cull, cold slag, etc.) cured inside the runner. However, this residue must be removed before the lead of the lead frame is punched by the punching device.

However, the residue remains firmly attached to the lead frame and is difficult to remove easily. Therefore, a residue removing means disclosed in Japanese Utility Model Publication No. 62-44528 is proposed. The features of this one are shown in FIG. 6 in particular, but the gist thereof will be explained in a more understandable manner with reference to FIGS. The code is
The same reference numerals as those in the above publication are attached.

In FIG. 5, 1 is a lead frame, 13
Is a molded body (resin molded body) formed by a resin molding device, and 3 is a residue (cold slag). In this device, the lead frame 1 is held by the pressure target body 8 and the lead frame 1 is bent as shown in the drawing, so that the residue 3 is forcibly separated from the lead frame.

[0007]

However, even with the above-mentioned conventional means, the residue 3 is not always completely peeled off from the lead frame 1, and as shown in FIG. There was a point. In particular, the adhesive force of the base end portion 3'of the residue 3 continuous with the mold body 13 is strong, and the residue 3 of the base end portion 3 'tends to remain as shown in FIG.

Therefore, an object of the present invention is to provide means for easily and surely separating and removing the residue from the lead frame.

[0009]

To this end, according to the present invention, a notch is formed at a portion corresponding to a runner through which a molten resin for molding a semiconductor chip passes.

[0010]

According to the above construction, since the portion of the lead frame corresponding to the runner is a notch, the molten resin does not adhere to the lead frame. Therefore, after the molten resin is cured, the cured residue remains. Can be separated and removed from the lead frame without difficulty.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a plan view of a lead frame set on a lower mold, and FIG. 2 is a sectional view of a main part of a resin molding device.
In this embodiment, two lead frames 1 are set on the lower die 12. The lead frame 1 is a metal plate,
The lands 2 are formed with a pitch. A semiconductor chip 5 is mounted on the land 2. Reference numeral 4 is a pin hole into which a feed pin (not shown) for feeding the lead frame 1 by pitch is inserted.

The upper die 11 is movable up and down with respect to the lower die 12, and when the upper die 11 descends onto the lower die 12, the lead frame 1 is sealed by the upper die 12 and the lower die 11 as shown in FIG. It A cavity 13 surrounding the semiconductor chip 5 is provided in the upper mold 11 and the lower mold 12, and a molten resin is pressed into the cavity 13. The lower mold 12 is formed with a hole 16 for accommodating a chip-shaped raw material resin (called a tablet) and a runner 17 communicating with the cavity 13 from the hole 16. Reference numeral 18 is a plunger that pushes up the resin 15, 19 is an ejector pin that pushes up the molded body cured in the cavity 13, 20 is a pressure-sensitive element that measures the internal pressure of the cavity 13, 21 is a base plate on which the pressure-sensitive element 20 is provided, 22 Is a push-up member of the base plate 21.

FIG. 3 is an enlarged view of portion A in FIG. 6
Is a slit-shaped notch formed in the lead frame 1, and is formed at a position corresponding to the runner 17.
In FIG. 2, resin 1 heated and melted by a heater (not shown)
5 is pushed up by the plunger 18 and is press-fitted into the cavity 13 through the runner 17. After the resin 15 is filled in the cavity 13, after the resin 15 is cured, the upper mold 11 and the lower mold 12 are opened, the push-up member 22 pushes up the base plate 21, and the ejector pin 19 is raised.
The lead frame 1 is taken out from the lower mold 11.

After forming the mold body in this way,
Prior to punching the lead 3 with a punching device, the residue hardened by the runner 17 has to be separated from the lead frame 1, but since the hardening part of the residue is the notch 6, the residue remains on the lead frame 1 at all. It is either not present or is only partially weakly attached, and thus can be easily separated from the lead frame 1.

The shape of the notch is not limited to the above-mentioned embodiment, and it may be locally formed near the base end (see FIG. 4) where the adhesive force is strong as described above. Forms a notch in the area corresponding to the runner 17,
It suffices that the residue does not adhere strongly to the lead frame 1.

[0016]

As described above, according to the present invention, since the notch is formed in the portion corresponding to the runner through which the molten resin for molding the semiconductor chip passes, the molten resin strongly adheres to the lead frame. Therefore, the resin residue can be separated and removed from the lead frame without difficulty.

[Brief description of drawings]

FIG. 1 is a plan view of a lead frame on a lower mold according to the present invention.

FIG. 2 is a sectional view of a main part of a resin molding device according to the present invention.

FIG. 3 is a partially enlarged view of a lead frame according to the present invention.

FIG. 4 is a partially enlarged view of a lead frame according to another embodiment of the present invention.

FIG. 5 is a side view of a residue removing means according to a conventional means.

FIG. 6 is a front view of a lead frame according to a conventional means.

[Explanation of symbols]

 1 lead frame 2 land 3 lead 5 semiconductor chip 6 notch 17 runner

Claims (1)

[Claims] 1. A lead frame formed by forming a lead on a side of a land on which a semiconductor chip is mounted, wherein a notch is formed at a location corresponding to a runner through which a molten resin for molding the semiconductor chip passes. A lead frame characterized by that.