摘要 |
<p>Method and apparatus for retaining a semiconductor wafer upon a pedestal within semiconductor wafer processing equipment. An electrostatic chuck contains a wafer support having a surface. Embedded beneath the surface is a number of electrodes defining a number of chucking zones. The electrodes are energized by a number of non-zero voltages thereby creating a variable, non-zero chucking force in each of the chucking zones. The method of retaining a substrate to a substrate support consists of biasing at least one of the electrodes with a first voltage of a first magnitude and biasing each previously unbiased electrode with a voltage of unequal magnitude of the initially biased electrode and every other previously unbiased electrode such that a non-zero chucking force exists in every zone. Wafer chucking zones of differing force improve uniformity of heat transfer gas layer distribution.</p> |