E-test Probe Mark Topology-induced Failure

In this paper, we show evidence of a unique failure at wafer sort that is caused by inline E-test probing on scribe line structures. This happens in spite of a safe probe distance from the prime die and the presence of typical seal ring surrounding chip periphery. Experimental results to relate probe marks topology created from mechanical probing on copper pads to sort outcome are presented. We discuss the failure mechanism and prove that probecard design and control is critical to avoid such fails.