Importance

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Abstract

Substrate inspection apparatus and methods, and illumination apparatus. The inspection apparatus and method includes memory for storing the desired features of the surface of the substrate, focussed illuminator for substantially uniformly illuminating a region of the surface of the substrate to be inspected. Additionally there is a sensor for imaging the region of the substrate illuminated by the illuminator, and a comparator responsive to the memory and sensor for comparing the imaged region of the substrate with the stored desired features of the substrate. The illumination apparatus is designed to provide substantially uniform focussed illumination along a narrow linear region. This apparatus includes first, second and third reflectors elliptically cylindrical in shape, each with its long axis substantially parallel to the long axes of each of the others. Fourth and fifth reflectors are also included with each being flat and mounted parallel to each other and at opposite ends of each of said first, second and third reflectors, and first, second and third linear light sources each mounted parallel to a corresponding one of said first, second and third reflectors with each of the light sources mounted so that it is at the first focus of the corresponding reflector and the illuminated linear region is at the second focus of each of the first, second and third reflectors. The questions raised in reexamination request No. 90/003,232, filed Oct. 29, 1993, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).

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First Claim