A method and apparatus (110) for determining the endpoint (e.g., TC1) of an etching step in a plasma etching process (101) for use in semiconductor wafer manufacturing. In one embodiment, an optical bandpass filter (e.g., 1542) is used for detecting a wavelength of electromagnetic emissions from elements...http://www.google.es/patents/US5552016?utm_source=gb-gplus-sharePatente US5552016 - Method and apparatus for etchback endpoint detection
Method and apparatus for etchback endpoint detection
