Abstract: A method of reflective lithography includes directing an asymmetric radiation (light) beam onto a reticle of a reflective lithography system. The asymmetry in the shape of the radiation beam may be used to compensate for a non-zero (non-normal) angle of incidence of the incident radiation. The radiation source shape may be configured to produce a substantially-symmetric output from the reticle. The shape of the radiation source may be configurable by any of a variety of suitable methods, for example by use of a configurable reflective device such as a fly's eye mirror, or by use of one or more suitable mirrors, lenses, and/or slits.

Abstract: Disclosed are a method of and a system for monitoring extreme ultraviolet (EUV) lithography mask flatness. An EUV mask, which is chucked to a chuck, can be scanned with a capacitance probe that generates elevation data for the EUV mask. From the elevation data, a first flatness profile can be generated. In one embodiment, the EUV mask can be rotated and rescanned.