Around each concave imprinted pattern, the compressed air that is caused by the imprint pressure, generates capillary bridges; and in case of a convex imprinted pattern the trapped air remaining inside the concave mold pattern gives rise to bubble defects. Thus, in order to remove such defective moldings, we proposed an immersion nanoimprint method where a compressible gaseous material is replaced by perfluorotributylamine (Fluorinert FC-43) as an incompressible liquid material. However, the insertion steps result in an excessive amount of FC-43 left behind after its utilization, and continues to remain in the cavity of the negative mold. This problem was resolved by controlling the amount of FC-43 liquid by applying three kinds of insertion techniques, namely dropping, spraying, and evaporation. In the cases of concave and convex imprinted patterns on a 460-nm-thick PMMA film, the defective moldings processes resulting in capillary bridges and bubbles defects were addressed. Among the FC-43 insertion techniques, in case of evaporation method, only a limited amount of inserted FC-43 was left behind, that resulted in the formation of some very small-sized capillary bridges and bubble defects. These results showed that in case of negative molds, complete filling can be achieved if air could be completely replaced by FC-43 which can be done by minimizing the amount of FC-43 liquid.
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