Scanning exposure apparatus in which light exposure is a function of the speed of the mask or substrate stage

Abstract

When the scanning of a mask stage and a substrate stage is started, an interferometer measures the position of the substrate stage, while an interferometer unit differentiates the output of the interferometer to give a speed signal on the substrate stage, and delivers this speed signal. A main control unit produces a target value for the amount of exposure light adapted to this speed signal. A light amount adjustment system adjusts the amount of exposure light from an exposure light source in response to the target value calculated by the main control unit. Thus, exposure with appropriate amount of light adapted to the speed of the substrate stage is performed over all of the time zones from the start of drive of the substrate stage in the scan direction until its standstill. Hence, the exposure time can be shortened, and the throughput can be increased, in comparison with exposure being performed only in the constant speed zone of the stage.

Dependencies are inferred from the claim text.