US Patent 9984958 Leadframe and semiconductor device

A semiconductor device includes a leadframe, a semiconductor chip, and an encapsulation resin encapsulating the leadframe and the semiconductor chip. The leadframe includes a first surface and a second surface facing away from the first surface. The semiconductor chip is mounted on the first surface of the leadframe. A part of the second surface of the leadframe is depressed toward the first surface to form a step surface. The step surface includes an uneven surface part where depressions are formed, and is covered with the encapsulation resin.