Influence of optical nonlinearities of the photoresist on the photolithographic process

Several commercial photoresists are characterized with respect to their changes of the real part of the refractive index during the bleaching process. A finite difference beam propagation algorithm is used to evaluate the impact of these refractive index changes on the lithographic process. It is shown, that the refractive index changes result in modified process windows, side wall angles, swing curves and iso/dense behavior.