Patent ID: 7446876

Claim:
A method of collecting reflectance data from a sample utilizing a reflectometer, including collecting reflectance data that includes at least some wavelengths below deep ultra-violet (DUV) wavelengths, the method comprising: creating light wavelengths below DUV wavelengths, the light being utilized to create at least one light beam in the reflectometer; transmitting the light beam in a least one environmentally controlled chamber; controlling an environment within the at least one environmentally controlled chamber to allow transmission of wavelengths below DUV light; directing the light beam on a sample; receiving at least a portion of the light beam within a spectrometer after the light beam has been reflected from the sample; providing a spectrometer output, the spectrometer output including, at least in part, an output portion related to light outside of the expected spectral range of the light beam; receiving the spectrometer output with a detector, the detector detecting data for wavelengths including at least some wavelengths below DUV wavelengths; and providing spectral filtering to limit the data generated by the reflectometer to wavelengths of an expected spectral range of the reflectometer.