Abstract: The invention relates to a plastic package for an integrated electronic semiconductor device to be encapsulated within a plastic body, the plastic bodyes formed using the step of molding said plastic body so as to fully enclose a semiconductor element, on which an integrated electronic circuit has been formed and which is placed onto a metal leadframe connected electrically to said integrated electronic circuit and carrying a plurality of terminal leads for external electric connection. To compensate the outward bends uncontrollably undergone by the plastic body due to thermal stresses during the molding step, a mold is used which has a cavity delimited by perimeter walls which define a concave-shaped volume. Preferably, at least one of the large walls, a bottom wall and a top wall, has a curvature inwardly of said mold. cavity. The curvature values are predetermined to compensate any outward curvature undergone by corresponding surfaces of said plastic body during the molding step.

Abstract: The invention relates to a method for forming a plastic package for an integrated electronic semiconductor device to be encapsulated within a plastic body, being of the type which comprises the step of molding said plastic body so as to fully enclose a semiconductor element, on which an integrated electronic circuit has been formed and which is placed onto a metal leadframe connected electrically to said integrated electronic circuit and carrying a plurality of terminal leads for external electric connection. To compensate the outward bends uncontrollably undergone by the plastic body due to thermal stresses during the molding step, a mold is used which has a cavity delimited by perimeter walls which define a concave-shaped volume. Preferably, at least one of the large walls, a bottom wall and a top wall, has a curvature inwardly of said mold cavity. The curvature values are predetermined to compensate any outward curvature undergone by corresponding surfaces of said plastic body during the molding step.

Abstract: A package for semiconductor devices provided with an encased metallic heat sink, wherein an encapsulating body of resin extends beyond the perimenter of the heat sink to form two side extensions, diametrically opposite with respect to a central portion of the body and elastically de-coupled from such a central portion of the resin body containing the heat sink and the semiconductor chip, by means of at least a thinned out zone of the resin body determined by one or more pairs of opposite grooves. Fastening points contemplated in said lateral extensions, are efficiently elastically de-coupled from the central portion of the body and the package is essentially free to blend along said pairs of opposite grooves without inducing stresses on the encased metallic heat sink onto which rests the semiconductor chip.

Abstract: A semiconductor device, comprising a lead frame connected to an IC chip in a resinous block and a metallic strip projecting unilaterally from that block along a heat sink, is fastened to that heat sink by a screw traversing aligned holes in the projecting strip portion and in an overlying clamp. The latter has a body of resilient sheet metal, such as brass, bent into a casing around the projecting strip portion and a cantilevered tongue overlying the resinous block, a projection on that tongue bearing upon the block under pressure of the fastening screw.