Fabrication of nanoscale magnetic domains using block-copolymer lithography

Abstract

The tendency of PS-b-PDMS to phase separate, the tunability of the resulting morphology and the sufficient etch contrast between PS and PDMS makes the block copolymer ideal for creating patterns that can be transferred onto magnetic media. The aim of this study was to determine optimal BCP film thicknesses that produce spherical micro-domains with long range order on a Co substrate brushed with PS-OH and to transfer this pattern onto the underlying Co. Thin films of PS-b-PDMS were spun-cast onto Co substrates brushed with PS-OH, solvent annealed and consequently etched in a series of steps that removed one constituent polymer at a time. Patterns with periods between 36-39nm and with great long-range order were observed for BCP film thicknesses in the 32-35 nm range and successful transfer of the pattern onto Co film was achieved, resulting in fabrication of nanoscale, discrete domains.