Platen clamping surface monitoring

摘要

An ion implanter includes a platen having a clamping surface configured to support a wafer for treatment with ions, the platen also having at least one pair of electrodes under the clamping surface, a clamping power supply configured to provide an AC signal to the at least one pair of electrodes and a sensed signal representative of the AC signal, and a controller. The controller is configured to receive the sensed signal from the clamping power supply when no wafer is clamped to the clamping surface. The controller is further configured to monitor the sensed signal and determine if the sensed signal is representative of deposits on the clamping surface exceeding a predetermined deposit threshold.