Fabrication of nanometer sized features on non-flat substrates using a nano-imprint lithography process

Abstract

TheStep and Flash Imprint Lithography (S-FIL TM ) process is a step and repeat nano-imprint lithography (NIL) technique based on UV curable low viscosity liquids. Generally nano-imprint lithography (NIL) is a negative acting process which makes an exact replica of the imprint mold and is subsequently dry developed to reveal the underlying substrate material. The authors have demonstrated a novel imprint process, which reverses the tone of the imprint and enables dry develop on nonflat wafers with good critical dimension control and resist layer thickness. This positive acting NIL process termed SFIL/R TM (reverse tone S-FIL), enables nano-imprinting over intrinsic substrate topology of the type commonly found on single side polished substrates. This paper describes the SFIL/R process and the results of pattern transfer on single side polished silicon wafers.

Advances in roll to roll processing of optics

“…The resolution limit of UV cure imprint is simply the minimum feature size of the master. For example, Molecular Imprints have reported resolution of 1 nm feature butting errors in UV imprint 13 .…”

Evaluation of nanoimprint lithography as a fabrication method of distributed feedback laser diodes

“…When applying NIL to such undulating substrates, it is possible that the mold will come in contact with a limited portion of the substrate, in which case severe nonuniformity of the residual layer thickness in the imprinted area will lead to large variations of the figures in the transferred patterns. Thus, we have formed diffraction gratings on a grating layer by using a reverse imprint based on SFIL/R, developed by Molecular Imprints, in order to suppress the variation of residual layer thickness resulting from the undulation of substrates [6]. We have aimed to improve the uniformity of the figures of grating corrugations by using the SFIL/R process.…”

Reverse-tone ultraviolet nanoimprint lithography with fluorescent UV-curable resins

“…Reverse-tone UV-NIL is adopted to overcome the problems arising from the substrate unevenness. 22) A nanoimprinted resist underlayer with low etching durability on a substrate is covered with another resist top layer with high etching durability in the reverse-tone process. Since the etching rate of the top layer is lower than that of the underlayer, nanoimprinted convex patterns of the underlayer are etched more rapidly and reverse-tone patterns are left in the top layer.…”