Direct UV-nanoimprint of polymer microring resonators as optical transducers

Inhalt:
This research presents current results of an UV-assisted nanoimprint lithography (UV-NIL) technology which is developed for direct structuring of polymer waveguides and microring resonators (MRRs). MRRs are key elements and transducers for optical sensor systems. Chemically functionalized imprint materials enable directly imprinted, functional polymer structures. A route towards residual layer free direct imprinting of large aspect ratios with a combined nanoimprint and photolithography (CNP) technique is discussed. CNP molds can be easily produced by leaving the antireflective chromium (arCr) hard mask after mold etching on top of the mold surface. The achieved surface free energy (SFE) of antisticking layers (ASLs) on the arCr was higher than for quartz, native SiO2 and thermal SiO2. However, the achieved ASL on the arCr was sufficient for imprinting. UV-NIL is suited to directly imprint and successfully release freestanding polymer structures with a resolution of sub-200 nm and an aspect ratio of about 5:1 with an active stamp area of 144 mm².