SEM imaging and Automated Defect Analysis at advanced technology nodes

As the scaling continues and industry moves to sub 1× nm nodes, Defect Review Scanning Electron Microscopy (DR-SEM) faces increasingly difficult challenges. The Defects of Interest (DOI) shrink as the features shrinks leading to imaging difficulty purely based on scale. The defect signal gets immersed in noise and the challenge of separating false from true is larger than ever. Also, more complex defect analysis is required for DOIs with 3D morphology and for previous layer DOI. A smart approach to DR-SEM must be adopted which allows for high quality imaging focused on yield improvements within a short cycle time. In this paper we demonstrate that reporting defects location in computer aided design (CAD) coordinates eliminates tool and user discrepancy in the inspection/review loop, facilitating robust DOI search at higher magnification and sensitivity. Further, smart implementation of defect analysis such as high landing energy see-through imaging, quantitative material analysis and tilt imaging on select DOI subsets allows for root-cause analysis and improved classification of defects which were previously misclassified or determined to be SNV (SEM non-visual).