Site portability and extrapolative accuracy of a predictive resist model

As design rules shrink, the goal for model-based OPC/RET schemes is to minimize the discrepancy between the intended pattern and the printed pattern, particularly among 2d structures. Errors in the OPC design often result from insufficient model calibration across the parameter space of the imaging system and the focus-exposure process window. Full-chip simulations can enable early detection of hotspots caused by OPC/RET errors, but often these OPC. model simulations have calibration limitations that result in undetected critical hotspots which limit the process window and yield. Also, as manufacturing processes are improved to drive yield enhancement, and are transferred to new facilities, the lithography tools and processes may differ from the original process used for OPC/RET model calibration conditions, potentially creating new types of hotspots in the patterned layer. In this work, we examine the predictive performance of rigorous physics-based 193 nm resist models in terms of portability and extrapolative accuracy. To test portability, the performance of a physical model calibrated using Id data from a development facility will be quantified using 1d and 2d hotspot data generated at a different manufacturing facility with a production attenuated-PSM lithography process at k(1) < 0.4. To test extrapolative accuracy, a similar test will be conducted using data generated at the manufacturing facility with illumination conditions which differ significantly from the original calibration conditions. Simulations of post-OPC process windows will be used to demonstrate application of calibrated physics-based resist models in hotspot characterization and mitigation.