SEMICONDUCTOR PACKAGE AND METHOD OF FABRICATION

摘要

A transfer molded plastic package having a cavity for accommodating a semiconductor chip is disclosed. A leadframe assembly process is shown wherein the leadframe finger pattern (13) is provided with a resilient or elastic O-ring bead (15,15'). Top and bottom housing plates (11,14) which have dimensions that are larger than the bead form the upper and lower surfaces of the package. These plates can be formed of any suitably rigid material. The chip or chips are connected to the lead frame and, along with the top and bottom plates, is located in a transfer mold. The mold cavities include faces which press against the plates which are held apart by the O-ring bead so that the bead is compressed by the mold closure. A plastic encapsulant (12) is molded around the periphery of the plates so that the leadframe fingers are secured therein to become package pins. The mold faces being pressed against the two plates precludes encapsulant from their faces which then become the outer faces of the package. The O-ring bead precludes the encapsulant from coming into contact with the semiconductor chip during the molding operation thereby creating a cavity package.