Abstract: A metal heat sink baseplate of a resin-encapsulated semiconductor power device, onto which the semiconductor die is bonded, is provided with one or more raised portions near the perimeter of the bound area of the semiconductor die, onto which ground wires may be welded in order to increase the reliability of wire connections realized between ground connecting pads and the metallic heat sink baseplate itself. The raised portions are preferably obtained by deep drawing the metal of the baseplate. A Single-In-Line semiconductor device is shown wherein the deep drawing of the metal heat sink baseplate for realizing a ridge on the assembly face, to be used for realizing wire ground connections is formed in a separation zone between a portion of the metallic baseplate which extends beyond the perimeter of the encapsulating resin body and onto which the fastening means of an external heat sink are arranged, and the remaining part of the baseplate onto which the semiconductor die is bonded.