US Patent 7508504 Automatic wafer edge inspection and review system

A substrate illumination and inspection system provides for illuminating and inspecting a substrate particularly the substrate edge. The system uses a light diffuser with a plurality of lights disposed at its exterior or interior for providing uniform diffuse illumination of a substrate. An optic and imaging system exterior of the light diffuser are used to inspect the plurality of surfaces of the substrate including specular surfaces. The optic can be rotated radially relative to a center point of the substrate edge to allow for focused inspection of all surfaces of the substrate edge.