Patent ID: 9104120
Filing Date: 2015-08-11
Classification: G01B,G01N,G03F

Abstract:
1. An apparatus suitable for contrast enhancement in a metrology tool, comprising: an illumination source; a spatial light modulator (SLM); a beam splitter configured to direct a portion of light emanating from the illumination source along an illumination path to a surface of the spatial light modulator (SLM); an aperture stop disposed substantially at a pupil plane of the illumination path, the aperture stop having an aperture configured to transmit at least a portion of light directed from the surface of the SLM to a surface of one or more specimens; and a metrology tool configured to measure one or more characteristics of one or more metrology target structures of the one or more specimens, the metrology tool comprising: wherein the SLM is configured to control a contrast level of the metrology tool by controlling an illumination pupil function of the illumination transmitted through the aperture, the illumination pupil function controlled by controlling a profile of illumination impinging on the surface of the SLM from the illumination source; and a computing system communicatively coupled to the detector of the metrology tool and configured to determine one or more overlay characteristics utilizing collected illumination data from the detector.