Room-temperature capillary-imprint lithography for making micro-/nanostructures in large areas

Abstract

Compared to imprint techniques under the driving condition of external imprint pressure, imprint lithography under capillary force has the advantages of being suitable to produce large feature patterns, simple mold structure, very low imprint pressure, and conformal contact between the mold and the substrate. However, in existing capillary-force lithography, the necessary heating process will bring problems, such as separation between the mold and the substrate, long imprint time, shorter lifetime of the mold, etc. In this article, the authors propose a technique of room-temperature capillary-imprint lithography which is applied to making both micro- and nanostructures simultaneously in large areas under low temperature. In order to prevent the polydimethylsiloxane mold from swelling in the imprint process, a new ultraviolet curable resist is introduced in the imprint process. This resist contains no solvents and has a wide range of viscosity. Through the experiment, three-dimensional microstructures are replicated in large areas on the flat substrate as well as on curved substrate. Moreover, by utilizing a resist with low viscosity, combination features with linewidth of 1 μm and 100 nm are reproduced successfully in the resist by the imprint technique.