An illumination system for an extreme ultraviolet (EUV) lithography system may include multiple sources of EUV light. The system may combine the light from the multiple sources when illuminating a mask.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of and claims priority to U.S. patent application Ser. No. 10/339,789, filed Jan. 8, 2003 now U.S. Pat. No. 7,002,164.
