Stamp Fabrication for ultraviolet Nanoimprint Lithography

Abstract

This thesis investigates the fabrication of stamps for ultraviolet nanoimprint lithography (UV-NIL). UV-NIL is an attractive method for replacing optical lithography as a fabrication method as minimal size of the structures nears 20 nm.

Stamp fabrication methods were analysed, compared, and tried. Finally, a fabrication process integrating a transparent conductive atomic layer deposition (ALD) layer to dissipate charges during the electron beam lithography (EBL) patterning process was chosen. The ALD layer was sandwiched between the glass substrate and a pattern layer of silicon dioxide. Various test patterns, such as dots and lines, were fabricated. After defining the patterns via EBL, they were transferred to the pattern layer via a plasma etching step.

After pattern fabrication, the patterns were positioned on a mesa via a wet-etching step, producing a pedestal of about 15 µm height. Following the etching, the stamp was covered with a release layer, and the imprinting process on the NIL-addon of the mask aligner was investigated. The results were analysed and will be used for further improvement of the process.

Imprinting was successfully demonstrated on several different substrates with different surface roughnesses.