Fabrication of three-dimensional nanoimprint mold using inorganic resist in low accelerating voltage electron beam lithography

Three-dimensional (3D) resolution of inorganic resist pattern, which was exposed with control of acceleration voltage electron beam lithography (CAV-EBL) in low accelerating voltage was examined. The system can make features with varying developed-depths. Three-dimensional pattern with a few hundred nanometer linewidth was fabricated with a CAV-EBL. The pattern depths on inorganic resist were gradated with 5 nm depth-resolution per 30 V. By controlling the pattern depth, a seven stairs blade-shaped binary optics mold was fabricated, and then a replica pattern of the mold was made by using UV-NIL.