Size Dependence of Quick Cavity Filling Behavior in Ultraviolet Nanoimprint Lithography Using Pentafluoropropane Gas

概要

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Rapid bubble elimination using pentafuoropropane (CFH2CH2CF3, HFC-245fa, CAS No. 460-3-1) condensing gas is one of the most promising methods to realize ultrahigh-speed ultraviolet nanoimprint lithography (UV-NIL). In this study, we investigated the shrinkage behaviors and elimination time of bubbles for different cavity sizes and resist thicknesses by employing a UV-NIL stepper with a real-time monitoring system. As predicted, a smaller cavity size resulted in a faster filling. Unlike the prediction from an analysis model based on Stefan’s equation, a nonlinear decrease in bubble elimination time was observed in accordance with the decrease in cavity size (area). Instead, a linear relationship between bubble elimination time and cavity width was found for a certain range of cavity widths ($W$). In the cavity width, range from 25 to 340 μm, bubble elimination time was almost proportional to cavity width and could be defined as $0.00145\times W$ (s). When the cavity width was 25 μm, the complete filling time was less than 0.033 s, indicating the potential to realize a ultrahigh-throughput nanopatterning process. Regarding the effect of initial resist thickness on a bubble shrinkage behavior, bubble elimination time tended to increase with the decrease in resist thickness.
2010-06-25