OPTICAL DIFFRACTION FOR INTEGRATED CIRCUIT LEAD INSPECTION

摘要

An apparatus and a technique for detecting damage of lead (113) arranged in a generally periodic pattern which comprises means for directing a coherent light beam (109) at a plurality of adjacent leads; means for detecting an image at a distance (110) from the leads (113) at which the light beam would form a diffraction image having substantially uniform pattern; means for moving the pattern of leads (113) and the light beam (111) with respect to each other; and means for detecting damage of leads from variation in intensity of the detected image.