Patent ID: 7027226

Claim:
An optical element for extreme ultraviolet (EUV) radiation wavefront control that comprises: a pattern of at least two bilayer structures with a first bilayer structure comprising a first layer of a first material and a second layer of a second material and a second bilayer structure comprising a third layer of the first material and a fourth layer of the second material, wherein the thickness of the first layer is different than that of the third layer and the thickness of the second layer is different than that of the fourth layer and wherein the pattern is formed on the planar surface of a substrate or membrane and wherein the first material has a different index of refraction than that of the second material and characterized in that incident EUV radiation passing through a first bilayer structure is phase shifted relative to EUV radiation passing through a second bilayer structure by a desired value and characterized in that radiation passing through the first bilayer structure exhibits an amplitude transmission reduction of a desired first value and that radiation passing through the second bilayer structure exhibits an amplitude transmission reduction of a desired second value.