Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame
Reexamination Certificate
1995-10-04
2001-03-27
Potter, Roy (Department: 2872)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
C257S669000, C257S692000
Reexamination Certificate
active
06208017
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device in which a semiconductor chip and a lead frame bonded thereto via an insulating film are sealed with a resin and, more particularly, to a semiconductor device in which a semiconductor chip is mounted on the inner lead parts of a lead frame via an insulating layer.
Along with miniaturization and low profiling of semiconductor devices, lead frames with lead-on-chip (LOC) structure has been proposed. In the prior art LOC structure, a semiconductor chip is stuck on the rear surface of a lead frame using an insulating layer having an adhesive coating on both sides of an insulating film. A polyimide coating is given in the space between the semiconductor chip and the adhesive of the insulating layer. The semiconductor chip is electrically connected to the lead frame by means of bonding wires. The entire system is then sealed with a resin.
In the bonding part of the lead frame of this LOC structure, the lead frame is bonded onto the insulating layer, and the bonding part of the lead frame is electrically connected to the semiconductor chip by means of a bonding wire. In the bonding part of the prior art LOC structure as described above, the width of the inner lead is being enlarged in order to secure a wider area of bonding to the insulating layer.
In a semiconductor device employing a lead frame with the prior art LOC structure, there is a problem in that, during temperature cycling, peeling originates between the resin and the vicinity of the bonding part of the inner lead due to the difference in thermal expansion of various component members, and a crack developed with the peeling as the starting point reaches the bonding wire to break the bonding wire.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to provide a semiconductor device having a high bonding strength between a lead terminal bonded to a semiconductor chip via an insulating film.
A semiconductor device according to the present invention, comprises: a semiconductor chip; an insulating layer formed on said semiconductor chip; at least one lead provided for said semiconductor chip, said lead terminal frame having a bonding part adhered to a surface of said insulating film and an inner lead having first and second portions, said first portion of said inner lead connected to said bonding part and adhered to said surface of said insulating film, said first portion of said inner lead including a partially bent portion, said second portion of said inner lead being elongated from said first portion of said inner lead and apart from said insulating film; a bonding wire electrically connecting between said bonding part of said lead terminal and said semiconductor chip; and a mold sealing said semiconductor chip, said insulating film, said bonding part of said lead frame and said bonding wire.
In another aspect, a semiconductor device according to the present invention, comprises: a semiconductor chip; an insulating layer formed on said semiconductor chip; at least one lead terminal provided for said semiconductor chip, said lead terminal having an bonding part adhered to a surface of said insulating film and an inner lead elongated from said bonding part; a bonding wire electrically connecting between said bonding part of said lead terminal and said semiconductor chip; and a mold resin sealing said semiconductor chip, said insulating film, said bonding part of said lead frame and said bonding wire; said lead terminal further has an indented part including first and second portions, said first portion having narrower width than said bonding part, and said second portion having wider width than said first portion of and connected to said bonding part via said first portion.
In this invention, the bonding strength between the semiconductor chip and the lead terminal bonded thereto via the insulating film, and the bite of these components on the resin, can be improved, and the relative displacement of the component members can be reduced, by the formation of parts, with width narrower than that of the bonding parts, in the portions of the lead terminal where it is bonded to the insulating film, namely, by the formation of projected parts or indented parts on the tip of the inner leads and in the vicinity of the bonding parts halfway to the tips, of the lead terminal. In this way, breaking of the bonding wires due to temperature cycling can be prevented, and an excellent effect even compared with the conventional case of employing through holes can be obtained by giving narrow parts to the inner leads. In addition, this invention has an effect of preventing adverse effects of grown peelings on the bonding parts.
REFERENCES:
patent: 5137479 (1992-08-01), Ohikata et al.
patent: 5352139 (1994-10-01), Yaguchi et al.
patent: 5455200 (1995-10-01), Bigler et al.
patent: 1-135055 (1989-05-01), None
patent: 1-276655 (1989-11-01), None
patent: 2018956 (1990-01-01), None
patent: 4165661 (1992-06-01), None
NEC Corporation
Potter Roy
Young & Thompson
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