A semiconductor wafer processing apparatus for processing semiconductor wafers comprises a semiconductor wafer processing chamber in which a semiconductor wafer is processed, a process gas source in fluid communication with the processing chamber adapted to supply process gas into the processing chamber, a vacuum source adapted to exhaust process gas and byproducts of the processing from the processing chamber, and an electrostatic chuck assembly. The electrostatic chuck assembly comprises a support surface in a layer of ceramic material on which the semiconductor wafer is supported during processing of the wafer in the chamber, at least one electrostatic clamping electrode embedded in the layer of ceramic material, the at least one electrostatic clamping electrode operable to apply an electrostatic clamping force to the wafer on the support surface when an electrostatic clamping voltage is applied to the clamping electrode, and at least one declamping electrode embedded in the layer of ceramic material above the at least one electrostatic clamping electrode operable to provide a path for draining any residual charge between the wafer and the support surface when the electrostatic clamping voltage is no longer applied to the clamping electrode.