The present invention relates to a method and apparatus for remotely detecting impedance. It is specifically adapted for use on a polishing machine wherein the end point of polishing for removing a surface layer during the processing of semiconductor substrates is detected. A first, or stationary coil...http://www.google.de/patents/US5213655?utm_source=gb-gplus-sharePatent US5213655 - Device and method for detecting an end point in polishing operation
