Surface inspection system and method for using photo detector array to detect defects in inspection surface

摘要

A dark field surface inspection tool of the invention includes an illumination source for directing a light beam onto a work piece. The tool includes a scanning element for enabling selected inspection points on the work piece to be scanned by the light beam. During scanning, the light scattered by each inspection point generates light scattering patterns associated with the surface characteristics of the scanned inspection point. The tool includes a photo detector array having photosensitive elements arranged to receive light from the light scattering pattern, thereby capturing an image of the light scattering pattern for each inspection point. Comparison circuitry is included for comparing light scattering patterns with a reference image to enable the identification of defects at the inspection point. The invention also includes a dark field surface inspection method comprising illuminating an inspection surface with a light beam, capturing images of light scattered from the inspection surface and comparing those images with suitable reference images to detect defects in the inspection surface.