JPH07147367A - Lead frame and semiconductor integrated circuit device using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the strength of the dam bar of the lead frame and prevent deformation of the outer lead part during molding and transportation. [Structure] By making the width (A) of the dam bar 5 of the lead frame 1 at least twice the width (B) of the outer lead portion 4b, the strength of the dam bar 5 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a semiconductor integrated circuit device using the same, and more particularly to a QFP.
Multi-pin, narrow pitch LS like (Quad Flat Package)
The present invention relates to a technique effectively applied to a lead frame used for assembling an I package.

[0002]

2. Description of the Related Art A dam bar is provided on a lead frame used for assembling an LSI package. The dam bar is a member formed integrally with the lead in the middle of the lead, and when the semiconductor chip mounted on the lead frame is resin-sealed, the molten resin injected into the mold die from the gap between the leads and the die. It has a function as a support member for preventing the lead from being deformed as well as preventing the lead from flowing outside.

By the way, it is conceivable that the width of the dam bar (dimension in the extending direction of the lead) is designed to be substantially equal to the width of the outer lead portion. However, in such a case, in the case of a lead frame used for assembling a multi-pin, narrow-pitch LSI package such as QFP in recent years, the width of the dam bar becomes extremely narrow as the outer lead portion is miniaturized.

[0004]

However, when the width of the dam bar becomes extremely narrow, its strength decreases. Therefore, when the lead frame is mounted on the molding die and the semiconductor chip is resin-sealed, it is injected into the molding die. The pressure of the applied resin causes the dam bar to be easily deformed, which causes a problem that the outer lead portion integrally formed with the dam bar is deformed and a problem that the lead is easily deformed when the lead frame is transported. .

An object of the present invention is to provide a lead frame technique capable of preventing the deformation of the outer lead portion during molding or transportation by improving the strength of the dam bar.

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

[0007]

The typical ones of the inventions disclosed in the present application will be outlined below.

According to one aspect of the present invention, in a lead frame having a dam bar integrally formed with the lead in the middle of the lead, the width of the dam bar is set to be at least twice the width of the outer lead portion of the lead. is there.

[0009]

According to the above-mentioned means, since the strength of the dam bar is improved by widening the width of the dam bar, it is possible to prevent the outer lead portion from being deformed during molding or transportation.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a partially enlarged plan view showing an enlarged part (about 1/4 of the whole) of a lead frame which is an embodiment of the present invention.

The lead frame 1 is used, for example, in assembling a QFP, and has a die pad portion 2 on which a semiconductor chip is mounted, suspension leads 3 for supporting the die pad portion 2, and a plurality of lead frames arranged around the die pad portion 2. It is composed of a lead 4 of the book, a dam bar 5 and an outer frame 6 which are provided substantially in the middle of the inner lead portion 4a and the outer lead portion 4b of the lead 4. Lead frame 1
Is made of 42 alloy or Cu, and the above-mentioned members are integrally formed by pressing or etching.

In the lead frame 1 of this embodiment, the width of the dam bar 5 (the dimension of the lead 4 in the extending direction = A), which is generally almost equal to the width (B) of the outer lead portion 4b, is set to the outer lead portion 4b. The feature is that the width (B) is twice or more.

According to the above structure, the outer lead portion 4
Since it is possible to prevent the strength of the dam bar 5 from being lowered even if the width (B) of b or the pitch is reduced, as shown in FIG. 2, a part of the lead frame 1 (die pad portion 2 and inner lead portion 4a) is formed. When the resin is sealed with the resin 7, the pressure of the molten resin injected into the mold becomes uneven, and even if a strong pressure is applied to a part of the dam bar 5, the deformation of the dam bar 5 is prevented. It is possible to prevent deformation of the outer lead portion 4b integrally formed with the.
Further, the leads 4 are less likely to be deformed not only at the time of molding but also during the transportation of the lead frame 1, and the manufacturing yield of the QFP can be improved.

FIG. 3 shows a QFP 8 completed by molding the lead frame 1 of this embodiment and then cutting and removing the dam bar 5 with a press.

The invention made by the inventor of the present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above-described embodiment, the case where the present invention is applied to the lead frame having the dam bar formed integrally with the lead has been described. However, the present invention is applied to a so-called tape dam type lead frame in which the leads are fixed by an insulating tape instead of the dam bar. It is also possible to apply. In this case, as shown in FIG. 4, by increasing the width (A) of the tape dam 9, it is possible to obtain the same effect as that of the above embodiment.

[0018]

The effects obtained by the typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

According to the lead frame of the present invention in which the width of the dam bar is more than twice the width of the outer lead portion of the lead, the strength of the dam bar is improved, so that the outer lead portion is deformed when the lead frame is molded or transported. Can be prevented.

[Brief description of drawings]

FIG. 1 is a partially enlarged plan view of a lead frame that is an embodiment of the present invention.

FIG. 2 is a partially enlarged plan view of the lead frame after molding.

FIG. 3 is an overall plan view of a QFP that is an embodiment of the present invention.

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

[Explanation of symbols]

 1 Lead Frame 2 Die Pad Part 3 Suspended Lead 4 Lead 4a Inner Lead Part 4b Outer Lead Part 5 Dam Bar 6 Outer Frame 7 Resin 8 QFP 9 Tape Dam

Claims (3)

[Claims] 1. A lead frame having a dam bar formed integrally with the lead in the middle of the lead, wherein the width of the dam bar is at least twice the width of the outer lead portion of the lead. Lead frame to 2. A semiconductor integrated circuit device obtained by resin-sealing a semiconductor chip mounted on the lead frame according to claim 1. 3. The QFP according to claim 2, which is a QFP.
The semiconductor integrated circuit device described.