METHOD TO PROVIDE CONSISTENT ELECTROSTATIC CLAMPING THROUGH REAL TIME CONTROL OF ELECTROSTATIC CHARGE DEPOSITION IN AN ELECTROSTATIC CHUCK

An electrostatic clamp monitoring system has an electrostatic clamp configured to selectively electrostatically clamp a workpiece to a clamping surface associated therewith via one or more electrodes. A power supply is electrically coupled to the electrostatic clamp and configured to selectively sup...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: Reynolds, William P, McIntyre, Edward K
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:An electrostatic clamp monitoring system has an electrostatic clamp configured to selectively electrostatically clamp a workpiece to a clamping surface associated therewith via one or more electrodes. A power supply is electrically coupled to the electrostatic clamp and configured to selectively supply a clamping voltage at a clamping frequency to the electrostatic clamp. A data acquisition system measures a current supplied to the one or more electrodes, and a controller integrates the measured current over time, therein determining a charge value associated a clamping force between the workpiece and electrostatic clamp. The controller is further configured to selectively vary one or more of the clamping voltage and clamping frequency based on the determined charge value, thereby maintaining a desired clamping force between the workpiece and electrostatic clamp.