NANOFABRICATION USING OPTIMIZED PROTON BEAM WRITING AND MASKED ION LITHOGRAPHY

Abstract

Proton Beam Writing (PBW) is a direct-write lithographic technique featuring minimal proximity effect coupled with uniform energy deposition in thin polymer layers. In this thesis, we present an optimized approach to nanofabrication using PBW. A spot size of 13 nm × 32 nm (STIM) was achieved using the system capable of automatic slit alignment and focusing ion beams. Fabrication of Au resolution standard is reported with 92 ± 5 % secondary electron collection efficiency per proton. We show fabrication of 30 nm channel fabrication in PMMA with an aspect ratio of 67. Fabrication of 42 nm linewidth is demonstrated to be used as master mold for nano-imprinting. Using masked ion lithography, we show nano-replication in photoresist down to 60 nm using high aspect ratio metal stencils fabricated using PBW. Monte Carlo simulation studies using Geant4 toolkit were performed to study the limits of masked ion lithography down to 10 nm.