Sub-10 nm lithography and development properties of inorganic resist by scanning electron beam

We report the self-developing properties of an AlF3-doped LiF inorganic resist under irradiation by a scanning electron beam with an energy of 20–50 keV are reported. The self-development properties strongly depended on both AlF3 concentration and film thickness. To explain this behavior, we presented an exposure model that takes into account a balance between a carbon contamination and a diffusion process. By optimizing resist qualities, we were able to delineate 5 nm linewidth patterns with 60 nm periodicity using a 30 kV electron beam.