A MULTIPLE WORKING DISTANCE HEIGHT SENSOR USING MULTIPLE WAVELENGTHS

A system is disclosed. The system includes a stage assembly configured to receive a specimen and maintain a height of the specimen at a first working distance height during a first characterization mode and an additional working distance height during an additional characterization mode. The system further includes an illumination source configured to generate an illumination beam. The system further includes an illumination arm including a set of optical elements configured to direct a portion of the illumination beam including illumination of a first wavelength to the specimen during the first characterization mode, and direct a portion of the illumination beam including illumination of an additional wavelength to the specimen during the additional characterization mode. The system further includes a detector assembly configured to receive illumination emanated from the specimen, and a controller configured to determine a specimen height value based on the illumination received by the detector assembly.