Patent ID: 6491757
Filing Date: 2002-12-10
Classification: C23C,H01L

Abstract:
Apparatus for processing a substrate comprising:a susceptor for supporting a substrate; an upper heat source spaced above the susceptor; a lower heat source spaced below the susceptor; and a controller providing power to said heat sources, a power ratio being defined as the power provided to the upper heat source divided by the power provided to the lower heat source, a heat ratio being defined as the amount of heat emitted from the upper heat source divided by the amount of heat emitted from the lower heat source, said controller being configured to vary said power ratio during a high temperature processing cycle of a substrate to thereby vary the heat ratio during the cycle, said controller being configured to reduce the power ratio just prior to a temperature ramp up portion of the cycle and increase the power ratio just prior to a temperature ramp down portion of the cycle.