Finite element simulation of absorbance modulation optical lithography

The technique of absorbance modulation optical lithography (AMOL) may provide an opportunity to improve the resolution in optical lithographical processes by allowing near-field images to be generated using light sources in the far-field. We report on finite element method (FEM) simulations of the photochromic layer in the AMOL process and demonstrate the ability of a change in absorbance to create sufficient contrast for imaging in an underlying photoresist. Alternative absorbance patterns, grating periods and photochromic thicknesses have also been examined. A second set of simulations have been created using the same techniques to observe the creation of a new absorbance pattern in the AMOL photochromic layer through the incident intensities of light.