Productivity improvement of high resolution inspection mode on TeraScan 597XR

At 32nm node and beyond, a common approach in defect inspection (high resolution inspection mode) to cope with aggressively OPCed mask patterns including SRAFs, is the utilization of small pixel size inspection. In fact the sensitivity is increased by using smaller pixel size for the high resolution inspection, but at the same time the throughput of the defect inspection tool falls. In this paper, we propose that one of the solutions to improve inspection throughput is pixel migration. KLA-Tencor's TeraScan[1] XR improves SNR (Signal to Noise Ratio) for higher sensitivity as comparison with TeraScanHR, so that pixel migration is possible. For tool performance confirmation, TeraScanXR has improved in defect sensitivity and SRAF MRC (Mask Rule Check) limitation as comparison with TeraScanHR. We confirmed that pixel migration is one of the solutions to control inspection time growth of next generation mask. For printability simulation of pixel migration, we confirmed the possibility of Brion's Mask-LMC[2] (Mask-Lithography Manufacturability Check) defect classification by lower SNR image. For experiment to achieve higher sensitivity, we confirmed defect sensitivity improvement with experimental condition and considered the model to achieve higher sensitivity.