Curved reticle by mechanical and phase bending along orthogonal axes

Abstract

Collection reflectors with multiple reflector elements defined on a curved surface are used to collect EUV optical radiation from an EUV emitting area. Each of the reflector elements can image the emitting area at or near a corresponding reflective element of a second multi-element reflector that overlaps radiation from each of the multiple reflector element of the collection reflector to illuminate a grating reticle. Systems with such a collection reflector can use fewer optical elements. In addition, grating reticles are defined on a curve substrate an include a plurality of grating phase steps so that the grating reticle provides phase curvature along two axes but with physical curvature along a single axis. Methods of producing varying duty cycle 1D patterns are also disclosed.

Dependencies are inferred from the claim text.