THIN-FILM MICROPATTERNING USING POLYMER MICROSPHERES

A new microlithographic strategy to create precise surface patterns in the submicron region was developed. Densely packed monolayers of monodisperse polymer microspheres (polystyrene) were deposited on a glass substrate using the Langmuir-Blodgett film technique. The spheres serve as a mask for the pattern to be created. Next, ZnS was deposited on the substrate as a thin film by thermal evaporation in vacuum. Finally, the mask (the spheres) was dissolved away to leave behind a surface with features (peaks) located where the interstitial spaces of the densely packed spheres had been. For 2-mum diameter shapes, the lattice spacing of the resulting pattern is approximately 900 nm and the individual peaks approximate trigonal pyramids. Subsequent overgrowth of thin films on the micropyramids gradually changes their geometry to a hemispherical shape.