OPO Reduction by Imaging Signal Optimization in an Advanced Memory Device Process

This paper will present a study about reducing on-product overlay (OPO) by optimizing imaging-based overlay (IBO) measurements utilizing newly developed extended wavelengths and optimal optical focus technologies on previous and current layers simultaneously in an advanced memory device process. Trends in memory device process variation using thicker/higher layer stacks along with more opaque process layers make this study especially crucial and topical to address these challenges.