METHOD FOR CLEANING OPTICAL ELEMENT IN IMMERSION LITHOGRAPHY

摘要

PROBLEM TO BE SOLVED: To provide systems and methods for making maintenance of an optical element of an immersion lithography apparatus easier and thereby improve the useful lifetime of the optical element.SOLUTION: An immersion lithography apparatus 100 includes: a working stage arranged to retain a workpiece; a projection system for projecting an image pattern; a fluid-supplying unit 5 for providing an immersion liquid 7 into a gap defined between an optical element 4 of the projection system and the workpiece W during an immersion lithography process; and a cleaning device to clean the optical element during a cleaning process.SELECTED DRAWING: Figure 1