US Patent 7339661 Dark field inspection system

Apparatus for inspection of a sample includes a radiation source, which is adapted to direct optical radiation onto an area of a surface of the sample, and a plurality of image sensors. Each of the image sensors is configured to receive the radiation scattered from the area into a different, respective angular range, so as to form respective images of the area. An image processor is adapted to process at least one of the respective images so as to detect a defect on the surface.