Fabrication of Multilayer Mirror Zone Plates and Gratings for Use with Soft X-Rays

Multilayer mirror gratings and Fresnel zone plates were produced using a multistep process utilizing microfabrication techniques. The gratings were generated by holography and the zone plates by electron beam lithography on Mo/C multilayer mirrors. The pattern transfer was performed by reactive ion etching in a fluorinated plasma after an intermediate lift-off step. Gratings with pitches down to 0.24 µm as well as linear, circular (with 0.3 µm outer zone), and elliptical Fresnel zone plates (with 0.8µm outer zones) were produced.