Patent ID: 8164879

Claim:
A method for dechucking an electrostatic chuck, comprising: (a) holding a wafer with an electrostatic chuck, wherein a gas is located in a space between said wafer and said electrostatic chuck, wherein a repulsion applied on said wafer by said gas is less than an attraction applied on said wafer by at least a voltage of said electrostatic chuck; (b) reducing said voltage of said electrostatic chuck, such that said wafer is pushed away from said electrostatic chuck and at least a portion of said gas escapes; (c) increasing the voltage of said electrostatic chuck, such that a repulsion applied on said wafer by a residual gas is less than an attraction applied on said wafer by at least said voltage; (d) repeating steps (b) and (c) until a final residual gas located in said space has a final pressure value less than a threshold pressure value; and (e) moving said wafer away from said electrostatic chuck.