Patent ID: 7195693

Claim:
A method of maintaining the temperature level of a semiconductor wafer substantially uniform across the surface of a wafer being supported on the top surface of a pedestal with the wafer being heated on its upper side, while the pedestal is cooled below the wafer, the method comprising the steps of: circulating a gaseous medium between the pedestal top surface and the wafer to extract heat from the heated wafer; maintaining a liquid sink of vaporizable liquid within the pedestal and below the the surface thereof, the liquid vaporizing at a selected temperature level; translating liquid by wicking action from the liquid sink upwardly through a plurality of wicking sites extending downwardly from the underside of the surface of the pedestal to below the surface of the vaporizable liquid and distributed below and throughout the area of the wafer; and condensing vapor generated because of localized heating at the underside of the pedestal surface at a plurality of condensing sites distributed throughout and spaced apart from the wicking sites, the condensing sites extending from within the liquid sink to above the liquid sink.