Method and Apparatus for Combining EUV Sources

Abstract

An apparatus and method is provided, for combining two or more EUV (extreme ultra violet) sources for illumination of a reticle. According to the principles of the present invention two or more EUV sources are combined in a single illumination system, using multiple first mirror arrays, each of which is associated with a respective EUV source, and a single second mirror array defining a pupil, and configured to receive reflected EUV radiation from the plurality of first mirror arrays, and to illuminate the reticle. Preferably, the first mirror array associated with each EUV source has a fly's eye configuration, the single second mirror array has a fly's eye configuration, and a condenser is positioned between the single second mirror array and the reticle. The number of mirror elements in the second mirror array is equal to or greater than the total number of mirror elements in the first mirror array.

Dependencies are inferred from the claim text.