Periphery exposing method and apparatus therefor

摘要

Prior to a periphery exposing operation, a light emitting unit and a light receiving unit are retracted to a position separate from a wafer, and a calibrating operation is conducted in the retracted position utilizing a light shield plate different from the wafer to be exposed, thereby obtaining a servo control reference signal for the exposure. At the exposure of the periphery portion of the wafer, the exposure width is controlled according to the reference signal. It is therefore rendered possible to achieve exact peripheral exposure, including the intensity and intensity distribution of the exposing light beam immediately before the irradiation of the peripheral portion of the wafer.