US Patent 7189140 Methods using eddy current for calibrating a CMP tool

Methods and apparatus are provided for calibrating a chemical mechanical polishing (“CMP”) tool having a polishing station with a platen, an eddy current probe disposed within the platen, a polishing pad coupled to the platen, and a metal element disposed within the polishing station and configured to be selectively moved proximate the polishing pad. The method includes the steps of determining a thickness measurement of the polishing pad and adjusting at least one tool parameter based, in part, upon the determined thickness measurement of the polishing pad.