Abstract: An extreme ultraviolet lithography system may have a spatial filtering system in projection optics that reduce flare. A flare filter may be provided at the pupil plane to pass the required diffraction orders (at minimum 0th and +1 or 0th and ?1 orders) of the light from the mask, while blocking the effects of scattering from various mirrors used in the projection optics. By reducing flare, process window and critical dimension variation can be improved.

Abstract: In one embodiment of the present invention, thermal deformation or bending of membranes in a transition radiation emitting structure can be reduced by providing flex regions in the membranes or the membrane support structures. In a second embodiment, deformation of membranes is compensated for by fabricating the membranes to cooperatively bend in a similar manner and direction. In a third embodiment, deformation of the membrane is reduced by fabricating the membranes with an intrinsic tensile or compressive stress.

Abstract: A technique for introducing variable phase delay across portions of a spatially coherent light beam, such as a laser, without changing the focal length of the portions of the beam. A fly's-eye lens array is utilized to distribute the light for a more uniform illumination, but different length air gaps are introduced in the lens elements to provide a variable delay of portions of the beam. In a second scheme, a set of prisms is positioned in the path of the laser beam, in which the shape of the prism introduces variable phase delay across the cross-section of the beam.