Making a mark

A team of researchers from the University of Bath, UK, is developing a new nano-imprint process, which can improve the established techniques, such as lithography, ablation, and etching. The novel large-area nano-imprint process overcomes the limitations of other methods and lends itself to large-scale low-cost imprinting. New structures can be built at low efforts due to its potential application to pattern replication in hard substrates, including silicon, gallium nitride and ferroelectrics such as lithium niobate. The substrate that is to be nano-structured is initially spin-coated with a thin film of UV-sensitive imprint resist. This is followed by a short, low-temperature pre-bake to evaporate excess solvent and promote adhesion of the polymer film to the substrate. A polyethylene terephthalate (PET) master structure is applied to imprint a positive nano-dot structure surface into the softer UV-cured polymer resist.