Patent ID: 9081149
Filing Date: 2015-07-14
Classification: G02B,G03F

Abstract:
1. An auto-focusing system for wafer edge exposure, comprising: an optical module, comprising: a second mask with a second aperture; a photodetector, wherein the second aperture of the second mask and the first aperture of the first mask are arranged in mirror symmetry with respect to a semi-reflecting surface of the first optics and are of a same size, and wherein the light reflected from the wafer edge passes through the second optics and then is directed to the second mask by the first optics, and the photodetector is arranged on a side of the second mask opposite to the side on which the first optics is arranged, for collecting the light entering the second aperture of the second mask and then outputting a corresponding light intensity signal, a control module for outputting a control signal when the light intensity signal outputted from the photodetector is lower than the first light intensity signal; and an optical path adjusting module, comprising: