Novel Stress Migration Failure Analysis by EBSD-KAM

Stress migration (SM) in back-end-of-line (BEOL) copper interconnections is a key factor in evaluating the reliability of semiconductor processes. Copper voids tend to aggregate in areas with higher stress gradients, leading to interconnections with high resistance or open circuits, which can ultimately cause device failure in the copper interconnect process. In traditional SM failure analysis, the primary method to depict stress gradients is by examining abnormal profiles where stress-induced voids have aggregated. However, this approach cannot directly capture material change. In this study, we have successfully introduced the Kernel Average Misorientation (KAM) map of Electron Back Scatter Diffraction (EBSD) to analyze stress gradients distribution indirectly in metal's intrinsic quality changes.