Method and apparatus for inspection of a substrate by use of a rotating illumination source

摘要

A method and apparatus for inspection of a substrate and a cover glass covering the substrate provides consistent detection of defects in the substrate such as cracks and cracks in the cover glass free of visual inspection of the substrate and the cover glass. An electromagnetic radiating source produces infrared radiation which illuminates the substrate and cover glass at a predetermined azimuth angle. The azimuth angle is varied such that the substrate and cover glass are illuminated at a plurality of azimuth angles. The substrate and the cover glass reflect portions of the incident electromagnetic radiation. A radiation detector collects portions of the reflected radiation and creates a plurality of images therefrom which include indicia representative of the defect in the substrate and the crack in the cover glass. <IMAGE>