Patent ID: 7189973

Claim:
A reflectometer which operates at wavelengths that at least include some wavelengths below deep ultra-violet (DUV) wavelengths, the reflectometer comprising: a light source that creates light including wavelengths below DUV wavelengths, the light being utilized to create at least one light beam in the reflectometer; at least a first reflectometer chamber in which the light beam travels, the first reflectometer chamber sharing, at least at times, an environment with at least a portion of a process tool sample chamber so as to create a shared environment with the process tool sample chamber, the shared environment being sufficiently controlled so as to allow the transmission and measurement of light wavelengths below DUV wavelengths; and a detector configured to receive reflectance data from a sample in the process tool sample chamber, the detector detecting data for wavelengths at least below DUV wavelengths.