Sub-15nm nanoimprint molds and pattern transfer

This work addresses the challenges in fabricating sub-10nm sized features, dense (sub-15nm half-pitch) arbitrary-pattern nanoimprint molds, as well as pattern transfer of the molds using nanoimprint. The molds were fabricated using an optimized electron-beam lithography process with hydrogen silsesquioxane (HSQ) resist. Two different mold-processing routes were investigated: (1) HSQ patterns on top of a silicon substrate were directly used for nanoimprint and (2) the HSQ patterns on the mold were transferred into the underlying silicon substrate to increase the aspect ratio of the patterns prior to imprint. After the nanoimprint, lift-off was carried out to demonstrate that the pattern could be transferred into functional materials. The difference between the two mold-processing routes is discussed. The results show excellent resolution transfer throughout the process flow to create sub-15nm half-pitch patterns in functional materials.