Sub-50-nm structure patterning by combining nanoimprint lithography and anisotropic wet etching without considering original mold resolution

A novel strategy for fabricating nanostructures was demonstrated that combined nanoimprint lithography and anisotropic wet etching. The resolution of proposed method does not depend on that of an original imprint mold. Atomically sharp V-grooves were formed by anisotropic wet etching using a SiO₂ etching mask fabricated by nanoimprint lithography. Atomic scale precision was performed by anisotropic etchant of tetramethylammonium hydroxide solution with adding a small amount of surfactant at room temperature. Using the V-grooves as a template, Al₂O₃/Al was deposited and etched by angled Ar ion milling after planarization with thick resin. Sub-50-nm metal structures were achieved with 72% size reduction of the initial mold structure.