Patterning of PMMA by gold-nanoparticle initiated localized decomposition

The need for manipulating matter at its smallest scale has been a hot topic in research for the last decades. As the final goal of arranging single atoms has been achieved, research focuses on two targets: firstly, improving the capabilities of existing technologies towards nanometer resolution and secondly, finding new methods for producing nanostructures in a fast and easy way. Here, we present a new maskless method for sub-micro-patterning of poly(methyl methacrylate) (PMMA) thin films. By applying atomic-force-microscope (AFM) assisted nano-xerography, electric charges were locally injected with an AFM-tip into PMMA. The resulting electrostatic patterns attracted charged gold-nanoparticles, which were selectively deposited onto the PMMA layers with lateral dimensions below 200 nm. In a second step, heat treatment at 275 °C initiated a selective decomposition of the PMMA layer, only observed in PMMA-areas covered with nanoparticles, whereas uncovered areas were not modified by the heat treatment. Analyzing the grooves with the AFM, we found that lines with a width in the sub-micrometer range to several micrometers have successfully been realized. We propose this new and promising method to manufacture nano-grooves used as masking for lift-off processes, for functionalization of underlying areas, or for micro-contact-printing.