Patent ID: 8908149

Claim:
A system, comprising: catoptric imaging optics configured to image an object field in an object plane to an image field in an image plane, the catoptric imaging optics comprising a plurality of mirrors, the plurality of mirrors comprising a mirror that comprises a phase mask, the phase mask comprising a substrate and a plurality of dielectric layers on a surface of the substrate, wherein: the plurality of dielectric layers is stacked so that one dielectric layer is positioned on top of another dielectric layer in a first direction which is substantially perpendicular to the surface of the substrate; the surface of the substrate comprises regions extending perpendicular to the first direction; adjacent regions of the surface of the substrate are separated from each other by portions of the surface of the substrate extending parallel to the first direction so that the adjacent regions of the surface of the substrate are separated from each other in a direction parallel to the first direction; the regions of the surface of the substrate extending perpendicular to the first direction support the dielectric layers; the portions of the surface of the substrate extending parallel to the first direction contact multiple dielectric layers; and the system is configured to be used in a lithography system.