EUV multilayer defect compensation (MDC) by absorber pattern modification, film deposition, and multilayer peeling techniques

Making a multilayer defect-free extreme ultraviolet (EUV) blank is not possible today, and is unlikely to happen in the next few years. The method proposed by Luminescent is to compensate effects of multilayer defects on images by modifying the absorber patterns. Progress in MDC is the subject of this paper. The multilayer growth model was calibrated using real data – the top layer profile captured by AFM and cross section captured by TEM for programmed defects with corresponding AIT images. Multilayer defect profiles on repair sites were recovered by applying inverse methods with the calibrated model to AFM surface scans. The recovered defect profiles were fed into the MDC engine to calculate modified absorber patterns that would compensate for the defects. Further, a new method to compensate for phase errors by depositing materials in addition to absorber modifications has been developed. Simulation studies using this new method will be presented in this paper. Different options of multilayer peeling for compensating phase error, especially for bump defect, are also evaluated through simulation.