Combination of direct laser writing and soft lithography molds for combined nano- and microfabrication

This work presents a novel approach for combined micro- and nanofabrication based on the local laser exposure of an UV-curing material through a structured mold. The proposed process makes use of the high freedom of design of direct laser writing (DLW) and the high resolution of soft lithography molds (made e.g. from PDMS). By optimizing the exposure process it was possible to fabricate locally defined hierarchical structures with a height of around 16 um, that are fully covered with nanometer-sized holes using OrmoComp (R). Manual test imprints showed that the fabricated structures can be used for "step & repeat" nanoimprint processes. Furthermore, the local transfer of nanostructures into two different soft lithography resists (Katiobond 110707, mr-NIL210) was investigated. Diffusion of resist components into the PDMS mold was observed and could be prohibited by the use of hybrid molds, which employ OrmoComp as structure containing layer. First experiments revealed successful transfer of the mold's nanostructures into mr-NIL210 but still leave room for improvement concerning the process parameters.