Contact hole edge roughness: circles vs. stars

摘要

The edge roughness of straight lines has received intense focus in the past, whereas the edge roughness of contact holes has been relatively unexplored. Reductions in contact hole roughness can be shown to offer improvements in electrical breakdown voltages, or potentially the opportunity for reduced cellsize. This paper introduces two CD-SEM algorithms for characterizing the amplitude and frequency of contact hole edge roughness. When combined, these two metrics proved capable of detecting differences within four wafer pairs with varying dimension and processing. Increased roughness amplitude was shown to correlate to electrical breakdown failures.