SEM review color imaging detection of gate to source/drain short in 14nm finFET device (Conference Presentation)

Abstract

The introduction of finFET has contributed tremendously in making scaling beyond 20nm a reality. However, the complexity of these 3D high performance transistors generate inherent new defects that are difficult to detect and this heightens concerns over device quality and reliability at future technology nodes. New methods and approaches are thus needed to effectively detect and monitor this new class of defects. Color imaging in Scanning Electron Microscopy (SEM) is not a new phenomenon. However, its use in inline SEM based defect review in the semiconductor industry is relatively new. In this work SEM color imaging is used to enhance SEM review redetection of a buried defect, Gate to Source/Drain short in 14nm finFET device. Defect sites on the wafer are flagged as defect events by Bright Field (BF) defect inspection tools. The review tool uses SEM optics to redetect the defect event using a combination of very high electron landing energies in excess of 5 keV and high beam current of about 3,000 pA to confirm the existence of the defect. The defect signal is further processed through a color coder by the SEM review equipment to create a “false” color image to enhance defect redetection and help to accurately classify defect.