JPH073645Y2 - Lead frame for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of Invention] (Field of Industrial Application) The present invention relates to a lead frame for a semiconductor device, and more particularly to marking for identifying the lead frame.

(Prior Art) For example, in a general IC, a semiconductor element is fixed to a die pad of a lead frame, and a bonding pad of this semiconductor element and an inner lead of the lead frame are connected by a gold wire or an aluminum wire bonding wire. It is manufactured by sealing these with resin.

The lead frame used here is a die pad 1 for mounting a semiconductor element, as shown in FIG.
The tip was extended so as to surround the die pad
Twelve inner leads 2, a dam bar (tie bar) 3 extending in a direction substantially orthogonal to the inner leads and integrally connecting the inner leads, and arranged outside the dam bar 3 so as to be connected to the respective inner leads. It is composed of external leads 4 and support bars 5 supporting the die pad 1. Reference numeral 6 is a side bar that constitutes an outer frame, and 7 is a tie bar that integrally supports the tips of the outer leads 4 and is supported by the side bar 6.

By the way, such a lead frame is formed into a desired shape by stamping or etching as shown in FIG. 3, and after the tips of the inner leads and the die pad are plated with a noble metal, the support bar is bent to form the die pad. A so-called depressing process for lowering the surface is performed, and taping is performed to prevent deformation of the internal leads in the case of a large number of leads.

The lead frame that has undergone the above-described processing steps is carefully inspected for deformation, scratches, burrs, plating rams, plating deviations, stains, and the like, and then packed and boxed.

However, in recent years, even in this field, there is a strong tendency for high-mix low-volume production, and lead frames of other types are mixed.
There are many human errors.

Such mistakes are unlikely to be mixed in a lead frame having a completely different shape, and even if they are mixed, they can be recognized at a glance. However, in order to reduce the manufacturing cost of the lead frame, of the stamping dies, only the die for punching out the vicinity of the pad should be compatible, the other parts should be shared, and other types of products with different pad sizes should be used. The way to get is common. For this reason, it is difficult to tell the difference between the product types at first glance, and when the product with the small pad size is mixed with the product with the large pad size, the product with the small pad size is hidden due to the difference in the pad size. It will be difficult to find.

In addition, even in the case of lead frames of the same type, the vertical direction may be wrong when packed.

Therefore, as shown in FIG. 4, a method has also been proposed in which an outer frame supporting a plurality of lead frame patterns is provided with a notch 8 which is different for each type of product, thereby identifying the mixing of different types of products.

(Problems to be solved by the invention) However, in this method, there are many problems such as another lead frame being caught in the notch and causing deformation, and the strength of the lead frame being reduced due to the reduction of the outer frame width due to the notch. There was a problem that it was not practical.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lead frame in which similar products can be easily identified and which is highly reliable.

[Constitution of device]

(Means for Solving the Problem) Therefore, in the lead frame of the present invention, the tie bar is provided with a marking formed by punching so that at least the shape or position of each type of lead frame is different.

(Operation) In the lead frame, the tie bar plays a smaller role than the outer frame in terms of strength. Therefore, even if the notch is formed and weakened, the strength of the lead frame as a whole does not decrease.

Further, the notch provided in the tie bar does not catch on another lead frame unlike the notch provided in the outer frame.

In addition, the mixture of different types can be seen at a glance when the lead frames are stacked, and the identification is extremely easy.

Furthermore, it is easy to distinguish lead frames that differ only in pad size.

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

The lead frame according to the embodiment of the present invention is, as shown in FIG.
Marking consisting of notches that indicate the type of lead frame on the tie bar 7 that integrally supports the tips of the external leads 4
18 is applied.

Other parts are the same as those of the lead frame of the conventional example shown in FIG. 3, and a square die pad 1 for mounting a semiconductor element, an inner lead 2, and a dam bar (which integrally connects the inner lead 2 with each other). Tie bar) 3, outer leads 4 extending from each inner lead 2, support bars 5 extending outward from the die pad 1 in two directions to support the die pad 1, side bars 6, and tips of the outer leads 4. It is composed of a tie bar 7 that is integrally supported.

According to this lead frame, since the tie bar 7 is marked, the type of the lead frame can be identified very easily without adversely affecting the strength of the lead frame.

Also, if the marking position or shape is asymmetric,
It is also possible to identify front / back inversion, 180 degree inversion, and the like.

Although the tie bar provided at the tip of the external lead is marked in the above embodiment, the tie bar (dam bar) 3 provided between the external lead and the internal lead is notched as shown in FIG. 28 markings may be provided.

(Effect of the Invention) As described above, according to the present invention, the tie bar of the lead frame is provided with the marking formed by the punching process so that at least the shape or position of each lead frame is different. Therefore, the type of product can be easily identified without adversely affecting the strength of the entire lead frame.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor device lead frame according to an embodiment of the present invention, FIG. 2 is a diagram showing a modification of the semiconductor device lead frame, and FIGS. 3 and 4 are conventional semiconductor devices. It is a figure which shows the lead frame for. 1 ... Die pad, 2 ... Internal lead, 3 ... Tie bar (dumb bar), 4 ... External lead, 5 ... Support bar, 6 ... Side bar, 7 ... Tie bar resin, 8, 18,
28: Notch (marking).

Claims (1)

[Scope of utility model registration request] 1. A lead frame comprising a plurality of inner leads, outer leads extending from the respective inner leads, and a tie bar integrally connecting the respective leads and supported by an outer frame. A lead frame for a semiconductor device, which is provided with a marking formed by punching so that at least the shape or position of each lead frame differs.