Bi-Layer nanoimprinting lithography for metal-assisted chemical etching with application on silicon mold replication

This paper reports a new type of nanoimprinting method called Bi-layer nanoimprinting lithography (BL-NIL), which can work along with metal-assisted chemical etching (MaCE) for fabricating nanostructures on silicon. In contrast to conventional nanoimprinting techniques, BL-NIL adds an interposing layer between the imprinting resist layer and silicon substrate. After the standard imprinting process, dry etching was used to etch away the residual imprinting layer and part of the interposing layer. Finally, the remaining interposing layer was wet-etched using its remover. This innovative approach can ensure cleanliness at the metal/silicon interface after metal lift-off processes, and therefore guarantees the success of MaCE. By combining BL-NIL and MaCE, expensive silicon molds with sub-micrometer/nanometer-scale feature sizes can be easily replicated and preserved. This is important for the application of nanoimprinting technologies in industrial manufacturing.