Patent ID: 8228658
Filing Date: 2012-07-24
Classification: H01L,H02N

Abstract:
1. A method for clamping and de-clamping a workpiece, the method comprising: providing an electrostatic clamp and a power source; placing the workpiece on a clamping surface of the electrostatic clamp; applying a clamping voltage at a first frequency to the electrostatic clamp via the power source, therein electrostatically clamping the workpiece to the electrostatic clamp with a first clamping force; halting the application of the clamping voltage at the first frequency and applying a second clamping voltage at a second frequency to the electrostatic clamp via the power source, wherein the second frequency is greater than the first frequency, therein electrostatically clamping the workpiece to the electrostatic clamp with a second clamping force, wherein one or more of the first frequency and second frequency of the clamping voltage are varied within a respective predetermined range during the respective application thereof; halting the application of the clamping voltage at the second frequency; and removing the workpiece from the clamping surface of the electrostatic clamp.