Quick Cavity Filling in UV Nanoimprint Using Pentafluoropropane

In the course of solving the bubble defect problem of UV Nanoimprint, it was found that filling of mold cavities during UV-nanoimprint can be completed within 5 s if pentafluoropropane is used as ambience. In this work, by employing a real-time monitoring system, bubble shrinkage in the recess of a mold for UV nanoimprint in air and in pentafluoropropane was observed. Then, the bubble elimination times for various pentafluoropropane flows were measured and the condition for the rapid elimination of bubbles was determined. The consumption of pentafluoropropane was considered and the cost of the rapid elimination of bubbles was roughly estimated. By measuring the bubble sizes at intervals of 0.1 s, the time evolution of bubble shrinkage was monitored and the results were converted into time evolution of mold sinking. The mold sinking for the UV nanoimprint in vacuum was also estimated by simulations based on Stefan's equation. It was found that the process speed in pentafluoropropane was equivalent to that in vacuum, while the process speed in air was found to be much slower than that in vacuum.