LITHOGRAPHIC APPARATUS AND METHOD FOR ILLUMINATION UNIFORMITY CORRECTION AND UNIFORMITY DRIFT COMPENSATION.

摘要

A lithographic apparatus including a uniformity correction system is disclosed. Fingers move into and out of intersection with a radiation beam to correct an intensity of the radiation beam. Actuating devices are coupled to the fingers. A width of a tip of each of the fingers is half that of a width of the actuating devices. Systems and methods compensate for uniformity drift. An illumination slit uniformity caused by system drift is measured. First positions of uniformity compensators are determined based on the uniformity. Uniformity compensators are moved to the first respective positions. A substrate is exposed.