Uniformity in Patterns Imprinted Using Photo-Curable Liquid Polymer

Abstract

Imprint lithography is a candidate for high-resolution, high-throughput lithography using low-cost equipment. In particular, imprinting using photo-induced solidification is very attractive because it eliminates heat-up, cool-down time and avoids thermal expansion problems inherent in conventional thermal imprinting. We demonstrate the replication of uniform 100 nm line and space (L/S) patterns over a 5 mm×5 mm area at a time, a 60 nm L/S pattern and a 90-nm-wide line with an aspect ratio of 2 by imprinting using photo-induced solidification. We studied the removal of a base layer by O2 reactive ion etching (RIE) and determined the criteria for the base layer and imprinted patterns. Change in line width through O2 RIE is not affected by the base layer thickness but is affected by etching time. We found that granules generated in polymer during O2 RIE are slowly etched and the resulting long removal time of granules degrades the quality of imprinted patterns or prevents patterns from standing. It is necessary to achieve a base layer which is less than 100 nm thick or to change the O2 RIE conditions so that the polymer dose not granulate and/or use granulation-resistant polymers.