Single-step 3D nanolithography using plasma polymerized hexane films

Abstract

► Fabrication of nanostructures in 3D is an area of increased interest. ► Using plasma polymerized resists allows for conformal coating. ► Enables high resolution nanostructures to be defined on existing topography. ► Demonstrator shown: line grating at top and bottom of 20 μm trench. The fabrication of nanostructured textures on top of a microstructured topography is a topic of considerable interest, with a number of different approaches having been proposed, most of which are either cumbersome, or represent a radical departure from standard fabrication processes. In this work, we present a simple fabrication scheme for obtaining nanopatterned structures in 3D. The scheme relies on the use of plasma polymerized hexane as an electron beam resist. We utilize the unique property of plasma polymerization where the films are deposited with conformal coverage across pre-structured surfaces. This enables high resolution electron beam lithography to be performed on a pre-patterned/etched substrate. As a demonstrator, we show that nanometric line gratings can be produced at both the top and bottom surfaces of preetcheded, 15–20 μm deep, box arrays. The final structure can be replicated in PDMS, to provide a soft working stamp for subsequent 3D patterning.