This paper proposes a new oxidation model that can be applied to spatially non-uniform oxidations in a two dimensional scheme. The model describes the viscoelastic deformation of SiO2and the oxidation masking material as well as the oxidant diffusion in the growing SiO2. The Maxwell model is assumed for the stress relaxation function. The viscoelastic equation is solved using the boundary element method. Simulations aimed for the LOCOS oxide growth result in good agreement with experimental data. This model is found to be suitable for oxidation characterization for VLSIs.