Simple fabrication of UV nanoimprint templates using critical energy electron beam lithography

Abstract

Ultraviolet nanoimprint lithography (UV-NIL) is a promising nanoscale patterning method, but the template fabrication processes are expensive and time consuming because a chrome layer is necessary both as a charge dissipation layer to minimize pattern distortion during electron beam patterning and as a physical mask during subtractive quartz etching. In this paper, the authors propose a simple UV-NIL template fabrication scheme based on the direct electron beam patterning of hydrogen silsesquioxane (HSQ) on quartz substrates using critical energy electron beam lithography (CE-EBL). By operating at the critical energy (E2) where the charge balance between incoming and outgoing electrons leaves the surface neutral, charge induced pattern distortion typically seen on quartz is practically eliminated. This template fabrication process eliminates conventional deposition and etching of charge dissipation layers. Quartz with sub-100-nm HSQ structures was used as a UV-NIL template, and SU-8 polymer structures were successfully replicated by a UV nanoimprint process. This simple template fabrication approach may lead to the development of new biological devices, nanoelectronics, and optoelectronics.