JPS60195958A - Lead frame - Google Patents

Abstract

PURPOSE:To enhance the reliability and dimensional stability by forming the tab hanging lead connector of a frame in a recess shape of the prescribed width, thereby obtaining a range necessary to cut the tab hanging lead after molding. CONSTITUTION:A portion necessary to insert a tab hanging lead cutting jig is obtained in advance as a recess shape 7 formed on a frame 1, thereby cutting sufficiently the lead 2 even if the frame 1 except the portion required for inserting the jig is increased in width. Therefore, even if a semiconductor device made of a package of the size near the frame 1 as shown by two-dotted chain line is manufactured, the leads 2 are effectively cut after molding, and the cavity formed in a mold is the same as the package 8. Thus, a distance from the end of the frame can be very shortened. Accordingly, a resin flash occurred therebetween can be reduced extremely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technique that is generally effective in improving the reliability of semiconductor devices.

[Background Art] Usually, a resin molded semiconductor device is manufactured by attaching a pellet to the tab of a lead frame, and then making an electrical connection by wire bonding the bonding pad of the pellet to the lead. It is formed by molding with a resin such as epoxy resin using a mold, and then cutting and bending the leads.

The resin molding process described above involves injecting resin at a predetermined pressure into the cavity formed between the upper and lower molds while the lead frame is held between the upper and lower molds. This is done by

At that time, a so-called resin flash phenomenon occurs in which the resin pops out from the small gap created between the upper mold and the lower mold, but the resin (paris) that pops out due to this phenomenon acts as a dam to prevent the resin from flowing out. It reaches the frame portion of the lead frame (Japanese Unexamined Patent Publication No. 128466/1983).

On the other hand, in the tab suspension lead direction, since it is necessary to cut the tab suspension lead after resin molding, the frame is formed with enough room to insert a cutting mold. Therefore, the distance from the end of the cavity formed in the mold in the direction of the tab suspension lead to the frame, which is the dam, is
A possible problem is that the size is increased by the necessary size for insertion into the mold, and as a result, the resin flash that occurs during resin molding becomes large.

In addition, in semiconductor devices in which such a large resin flash has occurred, there is a problem in that the dimensional stability of the pancage is poor, which requires an extra so-called deburring process to remove the resin flash, and furthermore, in the deburring process, The inventors have discovered that the application of stress to the package portion causes problems such as defects such as pellet cracking within the puff cage.

[Object of the Invention] An object of the present invention is to provide a technique that is generally applicable and effective for improving the reliability of semiconductor devices.

Another object of the present invention is to provide a technique that is applicable and effective in manufacturing highly reliable semiconductor devices at low cost.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

That is, for a lead frame used when forming a resin molded semiconductor device, the tab suspension lead connection portion of the frame is made concave to secure a portion into which a tab suspension lead cutting jig is inserted. By increasing the width of the other frame parts and reducing the distance between the end of the mold cavity and the dam frame during resin molding, the width of the resin flash that occurs during resin molding can be reduced. It is something that can be reduced.

[Example] The figure shows a schematic plan view of a part of a lead frame for a DIP type semiconductor device, which is an example of the present invention. A commonly used frame has a shape shown in this figure as one unit, and a plurality of frames are connected in the left and right direction.

The lead frame shown in this embodiment has a skeleton formed by a frame 1, a tab suspension lead 2 directly connected to the frame 1, a dam 3, and a partition frame 4 formed between an adjacent unit. A tab 5 is fixed to the tip of the lead 2 at the center of the unit shape, and a lead 6 is formed approximately at the center of the lead 6, which is supported by a dam 3 and extends from a tie bar (partition frame) 4 to the vicinity of the tab 5. It is what it is.

In the lead frame according to this embodiment, the tab suspension lead connection portion of the frame 1 is formed with a predetermined concave shape 7, and the width of the frame l at other positions can be made sufficiently large. This part is almost the same as a commonly used lead frame.

When manufacturing a semiconductor device consisting of a resin-sealed package using the lead frame of this example, a concave shape 7 formed in the frame 1 is provided in advance to provide a portion necessary for inserting a tab suspension lead cutting jig. By doing so, even if the frame 1 is made wider than the portion required for inserting the cough jig, the tab hanging lead 2 can be sufficiently cut.

Therefore, even when manufacturing a semiconductor device consisting of a pancage of a size close to the frame l as shown by the two-dot chain line, the tab suspension lead 2 can be reliably cut after molding, and the mold Since the cavity formed in the mold is also the same as the pan cage 8, the distance from the end of the cavity to the frame can be made very short, so the resin flash that occurs during that time can also be made very small. .

As described above, the resin-sealed semiconductor device manufactured using the lead frame according to the present example can minimize the generated resin flash, thereby making it possible to provide a product consisting of a pancage with stable dimensions. Therefore, the so-called deburring process becomes unnecessary, and as a result, defects such as pellet cracking caused by stress applied to the pan cage in the deburring process can also be eliminated.

Furthermore, although the resin flash is larger by the amount of the recess in the concave portion 7 of the frame 1, the width is narrow enough to insert the tab hanging lead cutting jig, so the tab hanging lead can be cut after molding. Sometimes they can be removed at the same time.

The lead frame of this embodiment can be easily manufactured from a commonly used material such as 4270 or metal such as Kovar by a commonly used method such as press working or etching.

[Effects] (1) Regarding the lead frame used in a DIP type semiconductor device consisting of a resin-sealed package, by forming the tab-suspended lead connection portion of the frame in a predetermined concave shape, the tab-suspended lead after molding is Since the area necessary for cutting can be secured, resin molding can be performed with the end of the cavity formed in the molding die close to the frame.

(2) According to (1) above, the resin flash that occurs during resin molding can be reduced between the end of the cavity formed in the mold and the frame, so a pan cage with stable dimensions is formed. A semiconductor device can be provided.

(3) From (2) above, the deburring step can be omitted.

(4) According to (3) above, stress in the deburring process is not applied to the package, so it is possible to completely eliminate defects such as pellet cracking caused by the stress.

(5) According to +11 to (4) above, it is possible to provide a semiconductor device comprising a resin-sealed package with high reliability and good dimensional stability at a low cost.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, although the concave shape of the tab hanging lead connection part of the frame has been described as having a rectangular bottom, the concave shape is not limited to this, but any shape can be used as long as it is a shape that allows insertion of a cutting jig, such as an arc shape. There may be.

[Brief explanation of drawings]

The figure is a schematic plan view showing a part of a lead frame that is an embodiment of the present invention. 1...Frame, 2...Tab hanging lead, 3...
Dam, 4... Partition frame, 5... Tab, 6... Lead, 7... Concave shape, 8... Pan cage. Agent Patent Attorney Akio Takahashi

Claims (1)

[Scope of Claims] 1. A lead frame in which the tab suspension lead connection portion of the frame is formed in a predetermined concave shape. 2. The lead frame according to claim 1, wherein the width of the frame is substantially equal to the width of the frame at a position other than the concave shape.