METHOD AND APPARATUS FOR DETECTING DEFECTS IN REPEATED MICROMINIATURE PATTERNS

A method of inspecting repeating pattern devices according to which an image of the patterns is aligned with an array of pixels in the image detection plane of an optical detector. The image is magnified to a scale so that features of patterns repeated in the image occupy corresponding pixels or groups of pixels repeated in the array. Data is resolved from selected pixels and directly compared either to data obtained from corresponding pixels or from a data base, whereby defective features are identified through well-known data comparison techniques.