A thin plate thermally coupled to a cooling tube is positioned between a heating plate and a substrate and is adapted to serve as a heating plate or a cooling plate for the substrate. The thin plate and heating plate may be positioned in a load lock for the expeditious heating and cooling of large-area substrates. The cooling tube may include a first conduit, a second conduit disposed inside the first conduit having substantially no contact with the first conduit and containing a working fluid, and an isolation region disposed between the first conduit and the second conduit. The working fluid may be thermally decoupled from the thin plate by evacuating the isolation region and thermally coupled to the thin plate by filling the isolation region with a heat-conducting gas.