Pedestal with a thermally controlled platen

1. Field of Invention A workpiece support having dichotomy of thermal paths therethrough is provided for controlling the temperature of a workpiece support thereon. In one embodiment, a workpiece support includes a platen body having a plug centrally disposed in a workpiece support surface of the platen body. A lower surface of the plug defines a void between the plug and a bottom of the bore. The void creates a dichotomy of thermal paths through the platen body thus controlling the temperature of a wafer support surface. Alternatively, the plug and platen body may be fabricated from materials having different rates of thermal conductivity to created the dichotomy of thermal paths in addition to or in absence of the void.