Filling Behavior and Mold Release Force in UV Nanoimprinting Using PDMS Mold in Different Atmosphere

Bubble-free filling needs to be achieved to realize high-throughput mass production in ultraviolet nanoimprint lithography (UV-NIL). Polydimethylsiloxane (PDMS) is a gas-transmittable material because of its molecular features and is used as the base material for flexible molds in large-area UV-NIL. In this work, we investigated the filling behavior and mold release force of UV-NIL using a soft UV-curable PDMS mold in different atmospheres. Bubble-free filling was successfully demonstrated in air and 1,1,1,3,3-pentafluoropropane (PFP) gas atmosphere. The average release force following UV-NIL in PFP was 5.2 N, which was 70% smaller than that following UV-NIL in air. Defect-free fine nanopatterns with a width of 300 nm were fabricated by UV-NIL in PFP atmosphere.