Evaluation of new materials for plasmonic imaging lithography at 476 nm using near field scanning optical microscopy

A new resist formulation was successfully patterned using near field optical microscopy in order to simulate the conditions prevailing in silver based plasmonic imaging tools. Radiation at 476 nm was transmitted through a near field scanning optical microscopy fiber probe tip to cross-link a film of poly(4-methacrylmethyl styrene) via polymerization of pendant methacryloyl groups using camphorquinone and dimethyl aniline as an initiating system. Patterns were generated by scanning at several speeds in order to moderate the dose while maintaining a constant probe height of about 5 nm above the sample through shear force feedback. After development, lines corresponding to the exposed regions were observed. At a scanning speed of 4 μm/s, the observed pattern has a full width at half maximum of 275 nm and a height of ∼25 nm.