The present invention is a method and apparatus for cooling a semiconductor heat source. In one embodiment a thermal spreader is provided and includes a substrate for supporting the semiconductor heat source and a heat sink coupled to the substrate. A channel is disposed between the heat sink and substrate. The channel has at least one wall defined by the heat sink. The surface area of the channel wall defined by the heat sink is about 10 to about 100 times the surface area of a bottom surface of the semiconductor heat source. A coolant, for example liquid metal, circulates within the channel.