Optimization of illumination pupils and mask structures for proximity printing

Based on numerical simulations, we show the influence of the illumination on process windows in mask aligner lithography. The precise shaping of the illuminating light can lead to greatly increased process windows. We show that the best results are obtained when combining an optimized illumination with optimized mask structures and Optical Proximity Correction (OPC). We model the illumination according to the novel illumination system for SUSS MicroTec mask aligners, referred to as MO Exposure Optics, which allows a precise shaping of the angular spectrum and the partial coherence of the mask illuminating light by using Illumination Filter Plates (IFPs).