A method and an apparatus to determine characteristics of a film on a substrate in a processing chamber. An example of a method in accordance with one embodiment of the present invention includes impinging optical radiation upon the film, sensing optical radiation reflected from the film to form spectral...http://www.google.com.au/patents/US20030133126?utm_source=gb-gplus-sharePatent US20030133126 - Spectral reflectance for in-situ film characteristic measurements
