JPH02220468A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To reduce a cost and to enhance an operation efficiency by a method wherein dummy outer leads are formed in such a way that a shape from a dam bar to a part coming into contact with a part punched with a metal mold for dam-bar cutting use is identical and that the number of output terminals is identical to the maximum number of output terminals. CONSTITUTION:In a lead frame for semiconductor device use in which a size of a resin-sealed package and a width and a pitch of output terminals 3 are identical and the number of output terminals is smaller than the maximum number, dummy outer leads 7 are formed in the same parts as those of the maximum number of output terminals. Accordingly, cut chips of a dum bar can be removed simultaneously when the outer leads are cut off or can be removed easily when a metal mold for dam-bar cutting use is cleaned by means of air. Thereby, it is not necessary to prepare metal molds for dam-bar cutting use corresponding to the number of the output terminals whenever they are required; it is possible to comply with this operation only by one kind of metal mold for dam-bar cutting use; a cost can be reduced and an operation efficiency can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a lead frame in a resin-sealed semiconductor device.

(Prior art) Conventionally, as a technology in this field, for example, a semiconductor element is bonded to a lead frame part with a conductive resin or the like, and the electrode part of the semiconductor element and the lead frame are connected with a thin metal wire. Afterwards, the periphery is sealed with a thermosetting resin such as epoxy resin, the dam bar connecting the outer lead is cut, the outer lead is soldered, and its shape is shaped like a gullwing J-type lead. Assembling was performed by machining it into the desired shape.

The structure of the lead frame is as shown in FIG. That is, the outer leads 3 are led out from the resin molded part l, and these outer leads 3 are connected in the middle by the dam bar 2, and
They are connected by a guide rail 4 (or section bar).

Here, to give an example of the dimensions of each part of the lead frame, the width 11 of the outer lead 3 is 0.311j, and the pinch width is 1t.
is o, estm, spacing l is 0.35 fin, mold part 1
The distance 14 between the dam bar 2 and the dam bar 2 is 0.8 mm, and the width 1 s of the dam bar 2 is 0.5 mm.

Therefore, when cutting the dam bar 2 of the outer lead 3 of the lead frame configured in this way, the third
As shown in the figure, set the dam bar cutting mold and
The dam bar 2 between each outer lead 3 was removed to separate each outer lead 3. Here, 5 is the punch portion of the dam bur cant mold.

(Problem to be Solved by the Invention) As described above, there is no problem when the outer lead 3 is led out to the end of the mold part 1, but as shown in FIG. If the end of the dam bar 2 is not drawn out and becomes empty,
When cut, the chips 6 are punched out by the punch portion (hatched portion) 5 of the dam bur cant mold and remain. In other words, even if the pancage dimensions and the pitch and width of the outer leads are the same, if a dam bar of a package with a small number of output terminals, that is, a small number of outer leads, is canted with a normal dam bar cutting die, the result will be as shown in Figure 4. Then, chips 6 are generated. Then, the dam bar 2 is punched out by the punch part 5 of the dam bar cutting mold.
The part is discharged from the discharge hole (not shown), but since there is no space in the part where the chips 6 remain, there is no space for them to escape.
Chips 6 remain on the punch portion 5 of the dam bar cutting die, and according to the above dimensions, these chips are Z, XZ, that is, 0.
Because of the small size of 35 m x 0.5 am, there was a possibility that it would get between the individual parts of the mold even if air cleaning was performed, for example. Furthermore, if the above-mentioned dam bar cutting mold is used for a long period of time, it may cause the mold to be damaged. I had to prepare a mold.

The present invention solves the above-mentioned problem that when the number of output terminals differs even if the pan cage dimensions and the width and pitch of the output terminals are the same, a mold for cutting a dam bar corresponding to the number of output terminals is required. Dam bars can be cut using one type of dam bar canting mold, regardless of the pan cage dimensions, the width and pitch of the output terminals, and the number of output terminals, reducing costs and improving work efficiency. The purpose of the present invention is to provide a lead frame for a semiconductor device obtained by the present invention.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the same package dimensions when resin-sealed, and the width and pitch of the output terminals are the same.
In a lead frame for a semiconductor device having a smaller number of output terminals than the maximum number of output terminals, a dummy outer lead (7) is provided at the same location as that of the lead frame having the maximum number of output terminals.

(Function) According to the present invention, as described above, since the dummy outer lead (7) is provided, when the dam bar is cut with the dam bar cutting mold, micro-sized chips are removed. If you leave it behind, even if you clean it with air, it will get between the individual parts of the dam bar cutting mold,
If the dam bar cutting mold is used for a long period of time,
This can cause damage to the mold, so even if the package external shape is the same, it is necessary to prepare a mold for the dam bar cant corresponding to the number of output terminals. can be removed at the same time as the outer lead is cut off, or easily removed when cleaning the dam bar cutting mold with air.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial plan view of a lead frame for a semiconductor device showing an embodiment of the present invention, and shows a state in which a mold for cutting a dam bar is inserted.

In the figure, reference numeral 3 denotes an outer lead, in which two output terminals are missing at one end, and a dummy outer lead 7 whose molded side is cut is provided in this empty space.

Here, when the dam bar 2 of the lead frame is grease-sealed, the pan cage dimensions, output terminal width, and pinch are the same,
When the dam bar 2 is canted using the dam bar cutting mold of the puff cage that has the largest number of output terminals, the punch part 5 of the dam bar cutting mold allows the package dimensions, output terminal width, and pinch to be the same and the number of output terminals to be canted. As in the case of the package with the largest number of leads, the dam bar part 8 of the dummy outer lead 7 is also cut off. Since the outer end of the dummy outer lead 7 is connected to the guide rail 4 (or section bar) extending vertically from the dam bar 2, it is similar to the case where the lead frame shown in FIG. 4 is used. In addition, the punch portion 5 of the dam bar cutting die does not remain as chips.

Note that the dummy outer lead 7 protrudes a little from the dam bar 2 toward the mold part 1 side, but this does not mean that the dummy outer lead 7 protrudes from the line of the dam bar 2 to any position on the mold part l side as long as it does not enter the inside of the mold part l. There is no problem.

FIG. 5 is a partial plan view of a lead frame for a semiconductor device showing a second embodiment of the present invention, in which one end of a dummy outer lead 7 is not extended to the guide rail 4, but is extended from halfway toward the dam bar 2. It is bent and extended perpendicularly to the dam bar 2, and is connected to the dam bar 2 by taking a dimension that does not touch the punch portion 5 of the dam bar cutting die.

Next, FIG. 6 is a partial plan view of a lead frame for a semiconductor device showing a third embodiment of the present invention. Same as the output terminal, adjacent dummy outer leads are connected to the guide rail 4 (or section bar) from the part not hit by the punch of the dam bar cutting mold.

By configuring it in this way, it will not flap around.
A stable dummy outer lead can be obtained.

Next, FIG. 7 is a partial plan view of a lead frame for a semiconductor device showing a fourth embodiment of the present invention. Rail 4 (or section bar)
In other words, it is connected only by the dam bar 2, canting both the outside and the inside, and has a length of, for example, 1.
is set to a minimum of 21. When the dummy outer lead 7 is shaped like this, when the dam bar 2 is cut, the punch portion 5 of the dam bar cutting die is generated as chips, but this is at least 2-1. Since they are chips, they are large enough to be visually confirmed and can be easily removed by air cleaning.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, semiconductor devices having the same puff cage size, output terminal width and pitch when resin-sealed, and having a smaller number of output terminals than the maximum number of output terminals. Dummy outer leads are provided in the dam bar part of the lead frame at the same location as the one with the largest number of output terminals, so as long as the package dimensions, output terminal width, and pinch are the same, the number of output terminals can be reduced. A portion of the dam bar can be cut even in a lead frame for a semiconductor device having a smaller number of output terminals than that of a lead frame having a maximum number of output terminals using the dam bar cutting mold used for a lead frame having a maximum number of output terminals.

This eliminates the need to prepare molds for dam bar cuffs corresponding to the number of output terminals each time, and only one type of dam bar cutting mold can be used, reducing costs and improving work efficiency. You can improve your performance.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a lead frame for a semiconductor device showing an embodiment of the present invention, FIGS. 2 and 3 are partial plan views of a conventional lead frame for a semiconductor device, and FIG. 4 is a problem with the prior art. 5 is a partial plan view of a lead frame for a semiconductor device showing a second embodiment of the present invention, and FIG. 6 is a partial plan view of a lead frame for a semiconductor device showing a third embodiment of the present invention. FIG. 7 is a partial plan view of a lead frame for a semiconductor device showing a fourth embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Mold part, 2... Dam bar, 3... Outer lead, 5... Punch part of the dam bar cutting mold, 7... Dummy outer lead. Patent applicant Oki Electric Industry Co., Ltd. Agent Patent attorney Mamoru Shimizu (1 other person)
Fig. 5 Fig. 6 4th scale of Oishonko 1st lead frame seven-handed jump Fig. 7

Claims (1)

[Claims] In a lead frame for a semiconductor device having the same package dimensions, output terminal width and pitch, and a smaller number of output terminals than the maximum number, the shape between the dam bar and the punch part of the dam bar cutting die hits. A lead frame for a semiconductor device, characterized in that dummy outer leads are provided so that the number of output terminals is the same and the number of output terminals is the same as that of the largest number of output terminals.