Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – For plural devices
Reexamination Certificate
1999-02-10
2001-09-18
Whitehead, Jr., Carl (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
For plural devices
C257S724000, C257S725000
Reexamination Certificate
active
06291880
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a semiconductor device having a construction in which circuit components inclusive of a switching semiconductor device are molded by a resin mold.
Power semiconductor devices of this kind are heretofore described in JP-B-3-63822 and JP-B-6-80748. A switching semiconductor device is set on a lead frame with spaces of a predetermined gap and this lead frame is in turn set to a heat sink made of a metal. A resin is packed for integral molding to the entire exterior portion inclusive of the spaces so as to constitute a semiconductor device. Because a resin layer is interposed between a conductor layer to which the semiconductor device is fixed and the heat sink in this construction, a plurality of semiconductor devices can be mounted, and because the number of components is small, reliability is high. Nonetheless, this construction is not free from the following items.
As described above, the method packs the resin to the spaces in which the devices are set in advance. Therefore, voids are likely to be entrapped at the time of molding and the thickness of the resin layer is likely to fluctuate. Generally, the heat transfer rate of the resin layer of this kind is extremely low and even a slight error of the layer thickness results in great variance of a thermal resistance. In consequence, stable quality cannot be obtained easily in mass-production plants. It is difficult for the same reason to lower the thermal resistance by markedly reducing the thickness of the insulating layer (to not greater than 0.1 mm, for example).
Another item resides in that because conductor wiring is constituted by the lead frame, miniaturization is difficult to attain. For instance, it is very difficult to form wiring having complicated and very fine shapes for mounting a microcomputer which is to control a driver IC, for example.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a small-size power semiconductor device which can solve the difficulties of the methods described above and has a low thermal resistance but has high functional performance. In other words, the present invention provides a compact power semiconductor device capable of forming an insulating layer having a thin, uniform and stable film thickness and eventually, having a low thermal resistance, by applying a pre-molded sheet-like resin insulating layer made of a resin material different from a material of an exterior resin mold between a lead frame and a heat sink, that is, a base substrate.
It is another object of the present invention to provide with high reliability and at a low cost construction which can add high functional performance such as a driver IC for driving a switching semiconductor device, a microcomputer for controlling the driver IC and various protective circuits and communication circuits by incorporating a printed substrate capable of extending very small wiring.
To accomplish these objects, the present invention employs the following means.
In a semiconductor device including a main circuit part, a control circuit part, an exterior resin part, and a main terminal and a control terminal extended to the surface of the exterior resin part, the main circuit part has a construction in which a semiconductor device is fixed on an electrode plate and the electrode plate has a structure having a base substrate so disposed as to clamp a resin layer as an electric insulating layer; the control circuit part includes at least one circuit device on a substrate and the circuit device and the substrate are connected electrically and directly with each other; the main circuit part and the control circuit part are electrically connected; and at least a part of the base substrate is exposed substantially to the outer surface of the exterior resin part while other portions are integrally molded by the exterior resin part.
In a method of fabricating a semiconductor device including a main circuit part, a control circuit part, and a main terminal and a control terminal extended to a surface of an exterior resin part, the present invention provides a method of fabricating a semiconductor device which includes a step of fixing a semiconductor device as the main circuit part to a lead frame, a step of mounting at least one circuit device on a substrate as the control circuit part, a step of electrically connecting the semiconductor device and the substrate by electrically conductive wires, a step of connecting electrically the main circuit part and the control circuit part, an inspection step for selecting the control circuit part, a step of forming a resin layer on one of the surfaces of a base substrate, a step of mounting the lead frame on the resin layer and a step of molding them integrally by a resin.
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Okawa et al., “Amodel of Three Phase Inverter Hybrid IC with 60V/150A MOSFET”, 1995 IEEE, Aug. 10, 1995, pp. 898-903.
Gouda Masahiro
Ishii Makoto
Kamimura Noritaka
Ogawa Toshio
Saeki Junichi
Antonelli Terry Stout & Kraus LLP
Brophy Jamie L.
Hitachi , Ltd.
Jr. Carl Whitehead
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