Electric-driven flexible-roller nanoimprint lithography on the stress-sensitive warped wafer

Surface nanopatterning of semiconductor optoelectronic devices is a powerful way to improve their quality and performance. However, photoelectric devices' inherent stress sensitivity and inevitable warpage pose a huge challenge on fabricating nanostructures large-scale. Electric-driven flexible-roller nanoimprint lithography for nanopatterning the optoelectronic wafer is proposed in this study. The flexible nanoimprint template twining around a roller is continuously released and recovered, controlled by the roller's simple motion. The electric field applied to the template and substrate provides the driving force. The contact line of the template and the substrate gradually moves with the roller to enable scanning and adapting to the entire warped substrate, under the electric field. In addition, the driving force generated from electric field is applied to the surface of substrate, so that the substrate is free from external pressure. Furthermore, liquid resist completely fills in microcavities on the template by powerful electric field force, to ensure the fidelity of the nanostructures. The proposed nanoimprint technology is validated on the prototype. Finally, nano-grating structures are fabricated on a gallium nitride light-emitting diode chip adopting the solution, achieving polarization of the light source.