Fabrication of large area nanotemplate through nanosilver colloidal lithography

An alternative colloidal lithography applying nanosilver colloids has been developed for the fabrication of wafer-level large area nano templates. The nanotemplate consists of random arrays of nanopillar structures in the range of 50 to 200 nm. This approach uses nanosilver differently from the conventional colloidal lithographic methods applying silica or polystyrene with much smaller colloidal size in the range of 10 – 30 nm than those. The macroscopic uniformity was therefore much improved when spin coating deposited continuous multi-layered nanosilvers. A random array of isolated nanosilver islands with open spaces between them was created through optimized thermal annealing on a silicon substrate. Dimensional properties of nanosilver islands can be controlled by varying the following parameters: nanosilver concentration, spin-coating speed, and thermal annealing time. Subsequent etching of substrate silicon produced various nanopillar profiles, such as completely anisotropic, isotropic, and inversed diamond shapes with the meaningful controllability through varying well-known etch conditons.