As device technologies are shrinking, developing new techniques for fault isolation and defect localization is becoming a crucial challenge. In this paper, we have shown that by using memory and logic BIST diagnostic techniques, we are able to isolate the defect to two suspected nets. Thirdparty electronic design automation (EDA) tools were used for both MBIST and LBIST hardware implementation and for running diagnostics on the failing part. Using experienced and sophisticated failure analysis support, we were able to confirm with confidence that the stuck-at zero type of defect was caused by a signal line short at metal-5 to the ground line at metal-6.