Patent ID: 7952851

Claim:
An electrostatic chuck, comprising: an electrostatic clamping power source; a clamping plate having a clamping surface configured to accept a workpiece for electrostatic clamping thereon, the clamping plate comprising one or more electrodes, wherein the one or more electrodes are electrically connected to the electrostatic clamping power source, and wherein a hole extends through the clamping plate from the clamping surface to a backside of the clamping plate; a workpiece grounding apparatus, comprising: an electrically insulative housing positioned within the hole in the clamping plate, wherein the electrically insulative housing is generally hollow and comprises an open end facing the clamping surface and an opposite closed end, therein defining a bore in the electrically insulative housing; an electrically conductive shell positioned within the bore of the electrically insulative housing, wherein the electrically conductive shell is generally hollow and comprises a radial lip associated with the clamping surface, and wherein the electrically conductive shell is electrically insulated from the clamping plate by the electrically insulative housing; a spring positioned within the electrically conductive shell; and an arc pin having a tip associated with the clamping surface and a barrel portion, wherein the arc pin is biased toward the clamping surface via the spring, and wherein the barrel portion of the arc pin is slidingly confined within the electrically conductive shell via the radial lip of the electrically conductive shell; and an arc pin power source selectively electrically connected to the arc pin via the electrically conductive shell.