Polymer optical devices made by reverse and 3D nanoimprint lithography

Abstract

Nanoimprint lithography (NIL), with its apparent simplicity and resolution down to 6 nm, has become an attractive flexible and low-cost technique for nanopatterning of thin films, which themselves act as a mask for further nanofabrication steps, or which can be used as-printed thanks to the functionality of the thin film itself. In this work, we focus on the latter approach and report on our experiments carried out to fabricate organic photonic devices. Silicon stamps, with figures down to 100 nm, are fabricated using electron beam lithography and reactive ion etching. Different fabricated stamps include waveguides, gratings, splitters and interferometers. New fabrication techniques are investigated, namely the combination of NIL with optical lithography and reverse NIL. These two techniques allow producing three-dimensional structures. For the combination of NIL with optical lithography, an original approach is used consisting of a polymer stamp on top of a quartz + metal optical mask. In the case of reverse imprint and multilevel structures, particular attention is paid to adhesion between the stamp, the polymer and the substrate on which the layer is reported. These two techniques are very promising for the fabrication of complex polymer optical devices, like distributed feedback structures, in one step.