Abstract: An assembly for holding a substrate is provided. The substrate has a first surface, a second surface, opposite the first surface and an outer peripheral portion. The assembly includes a holding body having a support surface for supporting the substrate. The holding body has an aperture for passing therethrough a gas having a thermal conductivity. Additionally, the assembly includes a heat transferring seal having a first surface for frictionally engaging the second surface of the substrate. The heat transferring seal has a second surface, opposite the first surface, for frictionally engaging the support surface of the holding body. The heat transferring seal also has an inner peripheral portion defining an opening for receiving the gas. The heat transferring seal has a thermal conductivity closely matched with the first thermal conductivity of the gas for providing substantially uniform heat transfer across the substrate.