Patent ID: 8654305
Filing Date: 2014-02-18
Classification: G03F

Abstract:
1. An immersion lithography apparatus, comprising: a projection optical system; a stage configured to move a substrate on which the substrate is placed; a showerhead including an immersion liquid supply device and an immersion liquid discharge device configured to produce a flow of liquid between the projection optical system and the substrate; and a cleaning device configured to clean a portion of the projection optical system having been contacted with the immersion liquid by means of a cleaning gas to remove solid deposits therefrom, the cleaning device comprising: wherein the gas supply and discharge device is configured to produce a flow of gas to dry the portion of the projection optical system having been contacted with the immersion liquid, and wherein, in use, said gas flows across the portion of the projection optical system from the gas supply vent to the gas discharge vent to dry the portion of the projection optical system having been contacted with the immersion liquid, and wherein the cleaning device comprises an energy source configured to expose a projection optical system element to ultra-violet light while cleaning gas flows between the proiection optical system and the stage so as to remove solid deposits formed on the projection optical system element, wherein after completing exposure of the projection optical system element to the ultraviolet light, the cleaning device is configured to supply the cleaning gas to flush away removed solid deposits from said space toward the gas discharge vent.