Negative offset bipolar electrostatic chucks

摘要

A bipolar electrostatic chuck system having a bipolar electrostatic chuck for securely holding a wafer on the surface of the bipolar electrostatic chuck. The bipolar electrostatic chuck system includes a negative-offset power supply for providing a positive potential level and a negative potential level. The positive potential level is positively biased relative to a common reference voltage level by a first magnitude while the negative potential level is negatively biased relative to the same common reference voltage level by a second magnitude, which is larger than the first magnitude. Further, the bipolar electrostatic chuck includes a positive pole, which is coupled to the negative-offset power supply for biasing the positive pole at the positive potential level when the negative-offset power supply is turned on. Additionally, the bipolar electrostatic chuck includes a negative pole, which is coupled to the negative-offset power supply for biasing the negative pole at the negative potential level when the negative-offset power supply is turned on.