Modeling optical microscope images of integrated circuit structures

The waveguide model has been extended so that light scattering problems in semiconductor structures due to illumination of arbitrary polarization can be solved. A numerical algorithm has been developed so that once the characteristic matrix of the structure is set up, the reflected scattering matrix can be calculated efficiently. The validity of the model was examined both theoretically and experimentally, and good results have been obtained. With this modeling capability, we can successfully simulate accurate optical images of semiconductor structures obtained from various microscopes including polarization-dependent ones such as Nomarski microscopes.