Abstract: An apparatus and method are described for sealing semiconductor packages made from a thermoplastic resin wherein a lead frame is positioned vertically at a center axis of the apparatus and a pair of mold parts having cavities for housing flat moldings are positioned symmetrically as to said center axis. With the described method and apparatus, sealed semiconductor packages with excellent sealing properties can be produced.

Abstract: A semiconductor package comprising a pair of flat moldings made from a thermoplastic resin, one of the flat moldings having in the cavity a projection which is welded to a rear side of a tab of lead frame mounting a semiconductor thereon by melt heating, is excellent in heat dissipation and reliability and provides no deformation nor cutting of wires connecting the semiconductor and lead frames.

Abstract: A semiconductor package having a special cap shell wherein a flat molding having a window space with at least one level difference around the window space at the inside thereof is fitted with an ultraviolet-light transmissible lid at the level difference and an adhesive which has excellent sealing properties covers the periphery of the lid and the molding along and across the fitted portion so as to fix the lid to the molding without causing peeling of the adhesive.

Abstract: A process for packaging semiconductors or integrated circuits including semiconductors involves positioning a lead frame on which semiconductors or an integrated circuit are mounted between two thermoplastic resin moldings, at least one of which moldings has a cavity for holding the semiconductors or the integrated circuit and thereafter integrally joining the thermoplastic resin moldings under heat and pressure to the lead frame. An uneven surface is provided on at least a part of the surfaces to be joined of either or both of the two thermoplastic resin moldings. This uneven surface is formed around the cavity in a thermoplastic resin molding having a cavity or on a surface of the thermoplastic resin molding having no cavity which corresponds to the surface to be joined to the other thermoplastic molding having a cavity.