Abstract: A thermally enhanced BGA semiconductor device 10 having a heat sink 12 formed from a single piece of material with an expanded base and a pedestal in contact with a semiconductor chip 11. The pedestal is aligned through a window opening in a substrate 13 and the top surface of the base is adhered to the substrate. The heat sink 12 with an expanded base provides a path for rapid and efficient heat spreading and dissipation, a stand-off and an aid to improved package planarity during reflow to a PCB, and a long path for ingress of contaminants into the package. The device is amenable to high volume, low cost production.