Preparation of x-ray lithography masks using a tungsten reactive ion etching process

High-resolution x-ray lithography masks which use a tungsten absorbing layer were fabricated on polyimide support membranes. The tungsten was patterned with a reactive ion etching process. 70-nm lines and spaces have been replicated in polymethylmethacrylate (PMMA) using carbon K x rays. The process should allow high-resolution, high-contrast masks to be made for any wavelength.