Calculation of three-dimensional profiles of photoresist exposed by localized electric fields of high-transmission metal nano-apertures

Abstract

Using a simple theoretical model, we calculated three-dimensional profiles of photoresists that were exposed by arbitrarily-shaped localized fields of high-transmission metal nano-apertures. We applied the finite-difference timedomain (FDTD) method to obtain the localized field distributions. These distributions are generated by excitation of localized surface plasmon polaritons underneath a circular, C-shaped or bowtie-shaped aperture. We predicted the twodimensional exposure profiles of the photoresist as a function of the photoresist contrast when the results of the FDTD simulations were applied to the theoretical model. The three-dimensional exposure profiles of the photoresist were also visualized as a function of the exposure dose and the gap distance between the aperture and the photoresist. The threedimensional exposure profiles provided useful information in determining the process parameters for nano-patterning by plasmonic lithography using the high-transmission nano-aperture.