EUV Binary Phase Gratings: Fabrication and Application to Diffractive Optics

EUV Binary Phase Gratings: Fabrication and Application to Diffractive Optics F. Salmassi, * P.P. Naulleau, E.M. Gullikson, D.L. Olynick and J.A. Liddle Center for X-Ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA keywords: diffractive optics, EUV, electron-beam, lithography, Nanofabrication Abstract Diffractive optics play an important role in a variety of fields such as astronomy, microscopy, and lithography. For the extreme ultraviolet (EUV) region of the spectrum they have been difficult to make due to the extremely precise control required of their surface structure. We have developed a robust fabrication technique that achieves the required topographic control through the deposition of a thin film of Si on a Cr etch stop. We have fabricated binary phase gratings using this approach that have an efficiency of 80% of the theoretical maximum. The technique is applicable to any type of binary phase optical element. email: Fsalmassi@lbl.gov