JPH02294058A - Lead frame for ic - Google Patents

Abstract

PURPOSE:To prevent a lead from bending when an outer frame thereof is deformed, by making the connection part of the end portion of the tie ber of a lead frame and the outer frame narrower than the width of the tie bar of the linking part of outer leads. CONSTITUTION:In a resin body 1, an IC chip is mounted on an island and sealed. Cuter leads 4 led out from the resin body 1 foward the outside are linked by a tie bar 2 in the direction vertical to the outer leads 4. Width W of the tie bar 2 is narrower than the width W of the linking part of the outer leads 4. Both ends of the tie bar 2 are connected with an outer frame 3 by the connection parts of the tie bar 2 having the above mentioned width W. The twisting stress generating when the outer frame 3 is deformed by resin sealing is concentrated in the narrow connection part of the tie bar 2 connected with the outer frame 3, thereby absorbing the stress applied to the outer leads 4. Hence the generation of lead bending at the time of bending process of the outer lead 4 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IC lead frame used for a resin-sealed RC.

[Conventional technology]

As shown in Figure 2, the conventional IC lead frame has an I
The width of the typer 2, which connects the external leads 4 led out to the outside of the resin body 1 on which the C chip is mounted and sealed, and connects them to the outer frame 3, is equal to the width of the joint between the external leads 4. Width WI
The width W2 of the connection portion between both ends of the tieper 2 and the outer frame 3 was the same.

[Problem to be solved by the invention]

However, in the above-mentioned IC lead frame, when the outer frame 3 is deformed due to stress caused by resin sealing, torsional stress is applied to the outer lead 4 via the connection between the outer frame and the tie bar, and the outer lead is pushed away from the outer frame. When the lead is cut and bent, the lead bends at an angle θ as shown in FIG. 3, which is a drawback.

[Means to solve the problem]

The IC lead frame of the present invention has a connecting portion between the tie bar and the outer frame that is narrower than the width of the tie bar that connects the external leads. [Example] Fig. 1 is a partial plan view of an IC lead frame after resin sealing, showing an example of the present invention. As shown in the figure, I
A typer 2 connects the external leads 4 led out to the outside of the resin body 1 in which a C chip is mounted and sealed on an island in a vertical direction with the external leads 4, and the external leads of the typer 2 are connected to both ends of the typer 2. The tieper 2 is connected to the outer frame 3 by a connecting portion of the tieper 2 having a width W2 narrower than the width W1 of the connecting portion between the two.

Here, the torsional stress that occurs when the outer frame 3 is deformed due to resin sealing etc. is concentrated on the thin connection part of the tieper 2 connected to the outer frame 3, and the connection part is locally deformed. The stress applied to the lead 4 can be absorbed, and the lead bending angle θ when bending the external lead 4 is reduced.
It becomes possible to prevent the occurrence of IF.

〔Effect of the invention〕

As explained above, in the present invention, the connection portion between the end of the tie bar of the lead frame and the tie bar is made narrower than the width of the tie bar at the portion connecting between the external leads, so that the outer frame 3 is reduced by stress caused by resin sealing or the like. This has the effect of preventing lead bending during bending of the external lead in the event of deformation.

Further, the dimensional accuracy and shape of the leads can be maintained accurately, and it is possible to cope with the reduction in external lead width and increase in the number of pins accompanying the miniaturization of ICs.

[Brief explanation of drawings]

FIG. 1 is a partial plan view of an IC lead frame after resin sealing showing an embodiment of the present invention, and FIG. 2 is a partial plan view of an IC lead frame after resin sealing using a conventional lead frame. , FIG. 3 is a perspective view of the semiconductor device with the frame outer frame deformed. 1... Resin body, 2... Tie bar, 3... Outer frame, 4
...External lead, W,, W2...Tie bar width, θ
...External lead bending angle.

Claims (1)

[Claims] In a lead frame having an external lead and a tie bar that interconnects the external leads, the width of the connecting portion connecting both ends of the tie bar and the outer frame is greater than the width of the connecting portion between the external leads of the tie bar. An IC lead frame characterized by having a narrow width.