Ultra-dense silicon nanowires using extreme ultraviolet interference lithography

Patterning of ultra-dense, large-area lines down to 11 nm half-pitch using extreme ultraviolet (EUV) interference lithography with two types of inorganic photoresist is shown. The resist patterns are transferred using plasma etching into silicon (Si) for both types of resist. 14 nm half-pitch silicon nanowires with 1:1 aspect ratio and square cross-sectional profile using a hafnium oxide based resist was achieved. For a silicon oxide based resist, the etching selectivity was shown to be critical, and a variety of etching strategies to overcome this deficiency are discussed.