Ultraviolet Nanoimprint Lithography in the Mixture of Condensable Gases with Different Vapor Pressures

UV nanoimprint lithography (UV-NIL) in condensable gases such as pentafluoropropane (PFP) has been recognized as one of the most promising methods to realize bubble-defect-free UV-NIL with low demolding forces when compared with that in ambient air and He. We have recently studied two condensable gases [trans-1-chloro3,3,3-trifluoropropene (CTFP) and trans-1,3,3,3-tetrafluoropropene (TFP)] with different vapor pressures and low global warming potentials (GWP) of <6. However, the resulting lithographic pattern quality in UV-NIL remains unclear using CTFP and TFP. In this work, the surface roughness of patterns fabricated using UV-NIL in the CTFP and TFP gases was investigated. In UV-NIL in a CTFP/TFP atmosphere, with an increase in the TFP fraction, the surface roughness decreased. It was also found that the linewidth of tens of nanometer size patterns can be linearly controlled by adjusting the CTFP/TFP fraction; for 70-nm-wide line patterns, the linewidth adjusting ratio was approximately 14%.