Enhancements in rigorous simulation of light diffraction from phase-shift masks

With the increasing importance of phase-shift masks (PSM), the rigorous simulation of the light diffraction from the mask becomes a standard technique in lithography simulation. The combination of rigorous simulation of light diffraction with scalar and vector imaging theory results in several possible model options. The paper presents an overview about these model options. A new approach to the modeling of oblique incidence of light on the mask is proposed. The performance of field decomposition techniques for two selected examples is discussed. The different model options are applied to the simulation of the imaging of an alternating PSM with a ArF scanner. Resist simulations are performed with a calibrated model. Simulation results are verified experimentally and presented via resist imaging data for different pitches.