A technique and apparatus is disclosed for the optical monitoring and measurement of a thin film (or small region on a surface) undergoing thickness and other changes while it is rotating. An optical signal is routed from the monitored area through the axis of rotation and decoupled from the monitored...http://www.google.com.au/patents/US7024063?utm_source=gb-gplus-sharePatent US7024063 - In-situ real-time monitoring technique and apparatus for endpoint detection of thin films during chemical/mechanical polishing planarization
