METHOD AND APPARATUS FOR CONTROLLING THE RADIAL TEMPERATURE GRADIENT OF A WAFER WHILE RAMPING THE WAFER TEMPERATURE

摘要

A method and apparatus for controlling the radial temperature gradients of a wafer (106) and a susceptor (102) while ramping the temperature of the wafer and susceptor using a first heat source (112) that is primarily directed at a central portion of the wafer, a second heat source (116) that is primarily directed at an outer portion of the wafer, a third heat source (122) that is primarily directed at a central portion of the susceptor, and a fourth heat source (126) that is primarily directed at an outer portion of the susceptor. Ramping of the wafer and susceptor temperature is accomplished by applying power to the first, second, third and fourth heat sources. During ramping, the ratio of the first and second heat source powers is varied as a function of the wafer temperature and the ratio of the third and fourth heat source powers is varied as a function of the susceptor temperature.