Releasing a workpiece from an electrostatic chuck

摘要

Method and apparatus for releasing a workpiece, such as a semiconductor wafer, from an electrostatic chuck. A "dechucking" voltage is applied to the chuck electrode having the same polarity as was used to retain the workpiece, but having a different magnitude selected to minimize the electrostatic attractive force between the workpiece and the chuck. There is an optimum value for the dechucking voltage which minimizes this force. The optimum value can be determined empirically, or it can be determined by a method based on the value of the current pulse produced when the workpiece is first mounted on the chuck.