Modeling latent-image formation in photolithography, using the Helmholtz equation

Abstract

A method for simulating latent image formation in a photoresist illuminated by partially coherent light is described. The latent image is calculated by repeatedly solving a boundary-value problem for the Helmholtz equation on a two-dimensional domain, using the finite-element method. The dependence of the developed image on defocus is investigated for the case of high numerical aperture. The obtained results are compared with those predicted by the vertical propagation model and the first-order model.