Method and apparatus for balancing an electrostatic force produced by an electrostatic chuck

摘要

The disclosure relates to an electrostatic chuck containing apparatus, and a concomitant method, for balancing the electrostatic force that the chuck imparts upon a workpiece. More specifically, the electrostatic chuck (100) contains a chuck body (110) having a pair of coplanar electrodes (106) embedded therein and a wafer spacing mask (102) containing a plurality of conductive support members (118) deposited upon a support surface of the chuck body. The support members maintain a wafer, or other workpiece, in a spaced-part relation with respect to the support surface of the chuck body. Each electrode (106) within the chuck is respectively connected to a terminal dual voltage power supply (126) having a centre tap (132). The centre tap of the power supply is connected to the wafer spacing mask (102). As such, variations in the distance between the wafer and the electrodes due to variations in dielectric thickness, wafer backside roughness, chuck surface roughness, chuck surface conductivity or other physical variations that may cause changes in the electrostatic force are balanced by having the spacing mask connected to the centre tap of the power supply.