SUB-10 NM DIRECT PATTERNING OF OXIDES USING AN ELECTRON BEAM — A REVIEW

This article reviews the progress made in the sub-10 nm electron beam patterning of metal oxides over the last thirty years. The patterning of inorganic resists began with metal halides, they were soon taken over by metal oxides due to their excellent environmental stability. However, these inorganic materials, both halides and oxides, suffered from the requirement of very steep dose, thus rendering them useless for practical applications. This gave way to highly electron beam-sensitive stabilized metal alkoxides and metal naphthenates, with sensitively close to conventional electron beam resists such as poly(methylmethacrylate) (PMMA) and calixarene. Furthermore, they show excellent line edge roughness characteristics at sub-10 nm scale, which is currently unmatched by any other electron beam resist. Recent applications of these resists such as an etch mask and their suitability as gate oxides will be highlighted.