A Fast Thermal-Curing Nanoimprint Resist Based on Cationic Polymerizable Epoxysiloxane

ABSTRACT: We synthesized a series of epoxysiloxane oligomers with controllable viscosity and polarity, and developed upon them a thermal-curable nanoimprint resist that was crosslinked in air at 110 oC within 30 seconds if pre-exposed to ultraviolet (UV) light. The oligomers were designed and synthesized via hydrosilylation of 4-vinyl-cyclohexane-1,2-epoxide with poly(methylhydrosiloxane) with tunable viscosity, polarity and crosslinking density. The resist exhibits excellent chemical and physical properties such as insensitivity toward oxygen, strong mechanical strength and high etching resistance. Using this resist, nanoscale patterns of different geometries with feature sizes as small as 30 nm were fabricated via a nanoimprint process based on UV-assisted thermal curing. The curing time for the resist was on the order of 10s of seconds at a moderate temperature with the help of UV light pre-exposure. This fast thermal curing speed was attributed to the large number of active cations generated upon UV exposure that facilitated the thermal polymerization process.