Charge integration based electrostatic clamp health monitor

摘要

An electrostatic clamp monitoring system has an electrostatic clamp configured to selectively electrostatically clamp a workpiece to a clamping surface via one or more electrodes. A power supply electrically coupled to the electrostatic clamp is configured to selectively supply a clamping voltage to the one or more electrodes. A data acquisition system is coupled to the power supply and configured to measure a current supplied to the one or more electrodes, therein defining a measured current. A controller integrates the measured current over time, therein determining a charge value associated a clamping force between the workpiece and electrostatic clamp. A memory stores the charge value associated with the clamping force over a plurality of clamping cycles, therein defining a plurality of charge values, and the controller determines a clamping capability of the electrostatic clamp based on a comparison of a currently determined charge value to the plurality of charge values.