Abstract: A mold is disclosed for semiconductor devices intended for surface mounting, being of a type which comprises a metal plate and a body of solidified plastic resin. It consists of two plates which delimit at least one hollow adapted to receive the plate and to contain resin for forming the device body. Two elements of the mold push the plate from opposed sides against the bottom of the hollow. The hollow has two side extensions which are delimited by the side surfaces of the plate edges, thereby solidified projections are formed thereon which separate readily after the molding process. Thus, a structure is obtained wherein the plate has its bottom surface and two side edge portions fully exposed to allow optimum and controllable soldering to a printed circuit board.