Direct UV-imprinting of hybrid-polymer photonic microring resonators and their characterization

The direct patterning of hybrid-polymer microring resonators with minimal residual layers by UV-assisted nanoimprint lithography is reported. The proposed stamp-and-repeat technology requires no post-processing. The imprint polymer was applied by spin-coating as a 130-150 nm thin initial film for an optimized processing. The importance of the initial film thickness is discussed in detail. Aspect ratios of more than 5:1 were realized with 2 mu m high ridge-waveguides and sub-400 nm coupling gaps on maximal 130 nm thin residual layers. The achieved ratio of structure height to residual layer thickness of 15.4 (2 mu m versus 130 nm) was much larger than the typical values in high-resolution imprinting and superseded the removal of the residual layer completely. The resonators are thought as biosensor transducers. High quality devices with Q-factors up to 13 000 were produced with a minimal set of process steps.