Patent ID: 7061614
Filing Date: 2006-06-13
Classification: G01B,G01J,G01N

Abstract:
1. A method for evaluating a sample with a broadband optical wafer metrology tool employing a broadband illumination system arranged to illuminate the sample with broadband light spanning a plurality of wavelengths contained within a broadband spectrum, said broadband illumination interacting with the sample and further including a detection system for collecting at least a fraction of the light after interacting with the sample, said method comprising: separating the broadband spectrum into at least two sub-bands wherein the frequency width of each sub-band is a fraction of the total frequency bandwidth; providing a unique optical sub-path along at least a portion of the optical path between the illumination system and the detection system for each sub-band, said unique optical sub-path containing a sub-band optical system including at least one of a particular optical component or environmental controls selected to optimize performance over the frequency width of the associated sub-band; whereby the performance of the wafer metrology tool is improved over the total frequency bandwidth.