Rapid fabrication of nano-structured quartz stamps

Abstract

Replication of surface nano-structures from a master stamp allows large-area volume production that is otherwise cost prohibitive through conventional direct-write methods, such as electron beam lithography and focused ion beam milling. However, the creation of a master stamp containing sophisticated patterns still requires significant time on such direct-write tools. We demonstrate a method for reducing this tool time by patterning smaller nano-structures, and then enlarging them to the desired size through isotropic etching. We can create circular structures of any arrangement and size, down to the patterning limits of the direct-write tools. Subsequent metal mask deposition, lift-off, and anisotropic etching transforms the circular patterns to out-of-plane pillar structures for the final stamp. A 1 cm2 area filled with a pattern of 200 nm diameter nano-holes spaced 520 nm apart, requires only 21 h to complete using our process, compared to 75 h using conventional fabrication. We demonstrate the utility and practicality of the quartz stamps through polymer embossing and replication. Embossed polymer nano-hole arrays are coated with a Cr/Au (5/100 nm) film to create surface plasmon resonance structures. Extraordinary optical transmission spectra from the metallized arrays show the expected spectral features when compared to focused ion beam milled structures.