US Patent 8002025 Containment of a wafer-chuck thermal interface fluid

A method includes circulating a heat transferring fluid in a substantially closed system including an interstice between a wafer and a chuck at a first pressure. The method further includes pumping the fluid out of the interstice and increasing the pressure of the fluid to a second pressure. The method further includes reducing the pressure of the fluid to the first pressure and returning the fluid to the interstice. In the system, the fluid in the interstice transfers heat from the wafer to the chuck, or vice versa, by conduction. The presence of a conducting fluid in the interstice thereby decreases the resistivity of the interface, and enables more efficient heat transfer from the wafer to the chuck.