Test structure failed node localization and analysis from die backside

In this work, backside failure analysis technique on test structure failed node isolation and analysis are presented. Compared to front side failure analysis method, backside failure analysis provides more significant information that is related to the root cause directly. Especially, in the failure situations such as failure related to interface between contact top and metal in the contact chain structure or failure due to high resistance stacked via connected to n+ active P well structure, front side failure analysis isnpsilat effective to localize the failed site or clearly reveal root cause form investigation of defect due to sample preparation shortage. However, backside failure analysis overcomes the limitation of front side analysis. It was applied successfully on open contact chain observation and passive voltage contract (PVC) failed stacked via localization on the n⁺ active area. Combined with following cross-sectional TEM analysis, the root cause was firmly concluded.