A system for regulating an etch process is provided. The system includes one or more light sources, each light source directing light to one or more features and/or gratings on a wafer. Light reflected from the features and/or gratings is collected by a measuring system, which processes the collected...http://www.google.com/patents/US7052575?utm_source=gb-gplus-sharePatent US7052575 - System and method for active control of etch process
