High aspect ratio silicon and polyimide nanopillars by combination of nanosphere lithography and intermediate mask pattern transfer

► Novel multilayer mask stack for high aspect ratio etching using nanosphere lithography. ► Silicon nanopillars with 75 nm diameter and an aspect ratio of 17. ► High aspect ratio polyimide nanopillars with sub-100 nm diameter. ► Silicon pillar covered surface showed superhydrophilic properties under repeated wetting conditions.