Application of multi-mask layers for high aspect ratio soft mold imprint

摘要

Soft mold imprinting has been widely used to improve quality and uniformity in large area nano-imprint processes because of its flexibility. However, the aspect ratio of soft mold imprinting is limited because of its physical properties. In this paper, a multi-mask layers transfer process was demonstrated to realize a high aspect ratio in the soft mold imprint process. In this process, a thin hard mask was used as an intermediate mask for a high aspect ratio mask layer fabrication. Based on this, a 60 nm line width gratings mask, whose aspect ratio is higher than 4, was fabricated; we also realized a uniform photonic crystal (PC) pattern on large and rough gallium nitride (GaN) epitaxial wafers.