Multiple imprinting in UV-based nanoimprint lithography: related material issues

Abstract

We will present resist and mold modifications which affect the adhesion forces at the mold/resist interface to assure multiple imprinting in a UV-based stepping process. A specifically modified resist is used in combination with an anti-adhesion layer on the quartz mold surface. The resist was modified with a fluorine-based additive, which migrates to the surface during spin-on processes creating a low energy surface. Auger spectroscopy clearly shows the enhancement of the fluorine at the surface of the resist. The anti-adhesion layer on the mold was characterized by electron spectroscopy for micro-analysis (ESMA) to determine its monolayer characteristic and uniformity. The surface energy of both the modified resist and the mold was determined as well. To demonstrate the success of these modifications, multiple imprints (up to 50 times) of different micro- and nanostructures were performed with one mold. After printing, the structures were transferred into silicon using conventional RIE processes.