JPH03248451A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a lead from bending and to reduce short-circuiting between leads caused by solder scraps by forming a tie bar for connecting a plurality of outer leads mutually of soluble or elastic resin which is different from a material of the outer lead. CONSTITUTION:A number of outer leads 1 are connected mutually by a tie bar 2. The tie bar 2 is formed of soluble and insulating resin and connects leads with the same thickness at the lead, spaced slightly apart from package resin 5. In such a lead frame, a tie bar can be removed readily by dissolving the tie bar 2 after resin sealing. Thereby, resin burr is not developed even if a sealing gate of a die is put on a lead and the necessity of cutting of a tie bar can be eliminated. According to this constitution, it is possible to prevent cutting residue of dam resin and to improve quality of a semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead frame used for assembling a semiconductor device with leads, and particularly to a lead frame with improved quality and workability.

[Conventional technology]

FIG. 4 is a plan view of essential parts of a resin-sealed semiconductor device assembled using a conventional lead frame. In FIG. 4, a large number of external leads 1 in a lead frame made by etching or pressing thin metal sheets are connected to each other by divers 4 to maintain the shape of the lead frame.
In addition, the diver 4 also serves as a dam to prevent the package resin 5 from flowing out further toward the outer end of the external lead 1 as a dam resin 6 through the gap between the upper and lower molds during resin sealing. There is.

[Problem to be solved by the invention]

In the conventional lead frame described above, the diver is made of the same material as the outer lead of the lead frame. Therefore, the diver must be cut, and a diver cutting process is required. Furthermore, in resin sealing, when the gate of the resin sealing mold is brought over the leads, resin particles remain on the side surfaces of the leads, which deteriorates solderability. Further, there is a disadvantage that residual dam resin tends to remain after diver cutting, causing lead bending after lead molding, and that residual dam resin is crimped onto the lead, impairing solderability.

[Means to solve the problem]

In order to solve the above problem, in the lead frame of the present invention, a diver that connects a plurality of external leads to each other is made of a soluble or elastic resin different from the external leads.

〔Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a partial plan view showing a part of a semiconductor device in a resin-sealed state using a lead frame according to an embodiment of the present invention. In FIG. 1, a number of external leads 1 are connected to each other by divers 2. As shown in FIG. Diver 2 is a soluble insulating resin with the same thickness as the lead.
The leads are connected with a slight gap from the package resin 5. In such a lead frame, the diver 2 can be easily removed by melting the diver 2 after resin sealing, and therefore there is no occurrence of resin flakes caused by bringing the mold's encapsulation gate onto the lead. Since diver cutting is no longer necessary, it is possible to prevent dam resin from remaining uncut and improve the quality of semiconductor devices.

FIG. 2 is a partial plan view of a resin-sealed semiconductor device using a lead frame according to another embodiment of the present invention. In FIG. 2, the diver 3 that connects the external lead 1 is made of a resilient and insulating resin that is different from the metal external lead 1. When such a lead frame is used to attach the leads and then perform resin sealing, resin sealing can be performed such that a part of the diver 3 enters inside the resin package 5. Therefore, as shown in the partial perspective view of Fig. 3, it is possible to bend and form the lead 1 while leaving the diver 3 intact without cutting it. It can also prevent bending.

〔Effect of the invention〕

As explained above, in the present invention, the diver is made of a soluble or elastic resin and is insulating, so even if the mold's encapsulation gate is placed on the lead, resin particles will not appear on the side of the lead. This does not occur, and since dam resin removal and diver cutting are not necessary, there is no remaining dam resin, and it is possible to prevent deterioration of solderability due to resin debris adhering to the leads. Also, by eliminating the dam resin, lead bending can be prevented. Particularly when elastic resin is used, the diver is molded while holding the leads, which has the effect of preventing bending of the leads and reducing short circuits between the leads due to solder waste.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of a resin-sealed semiconductor device using a lead frame according to a first embodiment of the present invention before lead molding, and FIG. 2 is a partial plan view of a semiconductor device using a second embodiment of the present invention. 3 is a partial perspective view of the semiconductor device shown in FIG. 2 after lead molding; FIG. 4 is a partial plan view of the resin-sealed semiconductor device using a conventional lead frame before lead molding; FIG. be. 1... External lead, 2, 3.4... Diver 5... Package resin, 6...
Dumb resin.

Claims (1)

[Claims] A lead frame for a resin-sealed semiconductor device that includes a plurality of external leads and a diver that connects the external leads to each other, wherein the diver is made of resin. .