Fabrication of Imprint Mold with Nanotrench Patterns by Edge Lithography

Abstract

SiO₂ nanoline with extremely high aspect ratio could be fabricated by the edge lithography, however, such a high aspect nanoline was fragile. Since nanotrench pattern was stronger than nanoline pattern, a new process was developed for obtaining the Si nanotrench from the SiO₂ nanoline in order to obtain a strong nanoimprint mold. A resist nanotrench pattern is fabricated by using only the resist coating and the resist etching. The process is much simpler than the lift-off process. The Si wafer is etched by the modified Bosch process. The fabricated Si trench width and depth are 35nm and 260nm, respectively. The Si trench pattern is replicated to polystyrene (PS) film on a silicon wafer by thermal nanoimprint lithography. The PS nanoline, whose width and height are 28 nm and 360 nm, is successfully fabricated.