Wafer heating chuck with dual zone backplane heating and segmented

Abstract

A wafer heating chuck includes a backplane for mounting the wafer thereon. A rear surface of the backplane includes an outer annular recess with an outer angled wall. An outer annular heater is located within the recess and has an outer surface complementarily angled with respect to the wall. An inner annular heater resides inside the outer heater, adjacent the rear surface. A clamping member secured to the backplane includes inner and outer retainers which separately clamp the inner and outer heaters, respectively, to the backplane to assure solid to solid contact for optimum heat transfer therebetween. Each inner retainer is held by a radially cantilevered segment so that tightening of one inner retainer does not affect clamping force applied by adjacent inner retainers. Similarly, the outer retainers operate on cantilevered segments to yield independent clamping forces. Sensors sense backplane temperature at the inner and outer regions. Sensors are mounted to the backplane proximate the inner and outer heaters to measure the temperature of the backplane. Coolant is directed through channels in the backplane and through channels in a cooling ring secured to a backplane to influence the temperature of the backplane. A controller connects to the heaters, the sensors and coolant supplies for temperature profiling to achieve temperature uniformity during processing for a wafer mounted to the backplane of the heating chuck.