2022 Volume 35 Issue 2 Pages 135-141
Droplet-dispensed ultraviolet nanoimprint lithography (UV-NIL) in helium enables adaptive material deposition to match pattern variations in a mold. It is a potential lithographic technology for semiconductor devices, but process throughput is an issue. UV-NIL in trans-1,3,3,3-tetrafluoro-propene (TFP) and 1-chloro-3,3,3-trifluoropropene (CTFP) gases has enabled bubble-free and high-throughput processes for spin-coated films. This study investigated the applicability of a mixed condensable TFP/CTFP gas to droplet-dispensed UV-NIL. The filling time in a local area of the mold in a mixed condensable gas atmosphere was as low as 1/30th that in helium. Similarly, the filling in the entire mold was faster in a mixed condensable gas atmosphere than in helium, and micropatterns could be filled within 1.6 s. When the droplets were exposed to the mixed TFP/CTFP gas, the droplet diameter of 108 µm increased to 127 µm owing to gas absorption. The quality obtained for an L/S 90-nm pattern was the same as for the pattern of a spin-coated film, but the line width of patterns fabricated by UV-NIL in ambient TFP/CTFP was 6 nm narrower than that for UV-NIL in He.
