Bilayer Resist Method for Room-Temperature Nanoimprint Lithography

A compact nanoimprint lithography (NIL) apparatus using the driving power of a servomotor has been newly developed. A bilayer resist method using hydrogen silsequioxane (HSQ) as a top layer and AZ photoresist as a bottom layer has been proposed to achieve high-aspect resist patterns on a nonflat surface for room-temperature nanoimprint lithography (RT-NIL). The etching rate ratio of HSQ to AZ photoresist was higher than 100 for O2 reactive ion etching (RIE), indicating that the HSQ top layer has sufficient etching tolerance. We have achieved the high-aspect nanostructure patterns of 100-nm-linewidth and 1-µm-height using the NIL apparatus developed here.