A cavity package is set forth along with a method of manufacturing thereof. According to one embodiment, the method comprises attaching a metal heat sink to a leadframe using an intermediate structure that is thermally conductive and electrically insulating; molding a plastic body around the heat sink and exposed leads of the leadframe to form a cavity, with partially and selectively exposed lead top surfaces, heat sink top surface, and heat sink bottom surface; attaching a semiconductor device die within cavity on to the exposed top surface of the heat sink using a thermal conductive material; wire bonding respective wire bond pads of the semiconductor device die to the exposed lead top surfaces and to the heat sink for grounding; and attaching a lid to the plastic molded body to protect the wire bonded device within cavity.