CONTAMINANT DETECTION METROLOGY SYSTEM, LITHOGRAPHIC APPARATUS, AND METHODS THEREOF

摘要

A system (400) includes an illumination system (402), a detector (404), and a comparator (406). The illumination system includes a radiation source (408) and a spatial light modulator (410). The radiation source generates a beam of radiation (442). The spatial light modulator directs the beam toward a surface (436) of an object (428) and adjusts a spatial intensity distribution of the beam at the surface. The detector receives radiation (444) scattered at the surface and by a structure (434) near the surface. The detector generates a detection signal based on the received radiation. The comparator receives the detection signal, generates a first image based on the detection signal, and distinguishes between a spurious signal and a signal corresponding to a presence of a foreign particle on the surface based on the first image and the adjusted spatial intensity distribution.