A surface mount semiconductor device is assembled by positioning an array of semiconductor dies with an array of metallic ground plane members between and beside the semiconductor dies. The arrays of dies and ground plane members are encapsulated in a molding compound. A redistribution layer is formed on the arrays of dies and ground plane members. The redistribution layer has an array of sets of redistribution conductors within a layer of insulating material. The redistribution conductors interconnect electrical contacts of the dies with external electrical contact elements of the device. As multiple devices are formed at the same time, adjacent devices are separated (singulated) by cutting along saw streets between the dies. The molding compound is interposed between tie bars of the ground plane members and the insulating material of the redistribution layer in the saw streets, and at the side surfaces of the singulated devices.