Novel process to improve defect problems for thermal nanoimprint lithography

The reliability of imprint patterns molded by stamps for industrial application of nanoimprint lithography (NIL) is an important issue. Usually, defects can be produced by incomplete filling of negative patterns and the shrinkage phenomenon of polymers in conventional NIL. In this paper, the patterns that undergo a varied temperature or varied pressure period during the thermal NIL process have been investigated, with the goal of resolving the shrinkage and defective filling problems of polymers. This paper also studies the effects on the formation of polymer patterns in several profiles of imprint processes. Consequently, it is observed that more precise patterns are formed by varied temperature (VT-NIL) and varied pressure (VP-NIL). The NIL (VT-NIL and VP-NIL) process has a free space compensation effect on the polymers in stamp cavities. From the results of the experiments, the polymer's filling capability can be improved. VT-NIL is merged with the VP-NIL, resulting in a better filling property. The patterns that have been imprinted in merged NIL are compared with the results of conventional NIL. This study achieves improvement in the reliability of the results of thermal NIL.