An RF-driven semiconductor chip is die-bonded to the top face of a metal plate. The semiconductor chip and the metal plate are molded together with outer leads in a plastic package in the form of a rectangular parallelepiped. The metal plate is exposed at the back face of the plastic package. The metal plate is not protruding from the front and rear side faces of the plastic package. The front and rear side faces of the metal plate are flush with the front and rear side faces of the plastic package and partially exposed at the front and rear side faces of the plastic package. The front and rear portions of the plastic package are centrally formed with respective cutaway portions each in the form of a rectangular parallelepiped. The top face of the metal plate is exposed in the cutaway portions formed centrally in the front and rear portions of the plastic package to form solder portions.
