Numerical calculation of angle-resolved light scattering characteristics of features with arbitrary shape, such as particle contaminations and surface defects, on a filmed surface is very useful to the development and calibration of wafer inspection tools. A model and associated code based on the discrete-dipole approximation used to compute the light scattering form a particle on a filmed surface is developed. The reflection interaction matrix is modified with the Sommerfeld integrals for filmed surfaces. 3D fast Fourier transform method is used for accelerating the computation. Model predicted scattering signatures for a 0.305 micrometers polystyrene latex sphere on a smooth thin layer of silicon dioxide film on silicon substrate are compared with experimental results. The incident beam has a wavelength of 632.8 nm and the incident angle is 70 degree. The comparison shows very good agreement between the modeling results and experimental results. The model is also checked with another numerical mode,, which further shows the validity of the model.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.