Abstract: A workpiece holder for semiconductor workpieces during treatment with a substantially cylindrical casing shaped like a hockey puck having an upper surface for receiving a workpiece, a lower surface, at least one bore between the surfaces for applying a vacuum and a hollow interior for a heat absorbing composition preferably one which melts above ambient temperature but below temperatures which might damage workpieces. Suitable compositions include Glauber's salt, and calcium chloride hexahydrate. In one embodiment, curved, substantially radially extending vanes are preferably provided in the interior space for causing radial flow when the casing is rotated or oscillated. In a second embodiment, a plurality of bores extend between a manifold which extends radially and a plurality of circumferential grooves.