Resin-sealed electronic apparatus for use in internal combustion engines

DETAILED DESCRIPTION It is therefore a primary objective of the present invention to provide a new and improved electronic apparatus capable of achieving enhanced durability (long life-time) at soldered portions of a power semiconductor device for use with internal combustion engines and also increasing stiffness of the entire structure thereof while offering increased resistance against bending or flexure stresses and yet reduced deformability and at the same time taking full advantage of such Sn--Sb alloy-based solder materials.
It is another object of the invention to accomplish the use of lead-less high-temperature solder materials for the overall structure of electronic apparatus in view of environmental problems.
(1) Electronic apparatus for use in internal combustion engines in accordance with the present invention is featured in that a substrate having a hybrid IC (referred to hereinafter as a "hybrid IC substrate") and a power semiconductor device are secured on a heat sink made of a metal, that said power semiconductor device is in contact with said heat sink by use of a soldering material comprised of an Sn--Sb alloy, and that this power semiconductor device and the hybrid IC substrate plus the heat sink as well as one or more input/output terminals are embedded in a package except for part of the input/output terminals, said package being made of epoxy at 70 to 90 weight percent of an inorganic filler material as machined by transfer mold techniques.
In accordance with another aspect of this invention, the power semiconductor device and the hybrid IC substrate plus the heat sink as well as part of input/output terminals are embedded in a transfer-molded epoxy package while this epoxy is preferably arranged so that the content amount of inorganic filler material thereof is specifically adjusted to permit its resultant linear expansion coefficient is midway in value between the linear expansion coefficient of said power semiconductor device and that of said heat sink.
In case an Sn--Sb alloy-based solder is employed as the solder material for use in contacting or coupling between the power semiconductor device (made of Si for example) and the heat sink (made of Cu for instance), effectuation of appropriate solder thickness management permits the Sn--Sb alloy-based solder to exhibit an action of suppressing thermal deformation (expansion, shrinkage) occurring due to linear expansion coefficient differences between Si and heat sink material