Enabling yield analysis with X-compact

X-compactor is an X-tolerant test response compactor that is useful for massive reduction of test data volume and test time. This paper presents a technique for identifying failing flip-flops during scan test directly from the compacted response obtained from X-compactor outputs. The identified failing flip-flops can be used for several purposes - as inputs to a scan-based diagnosis tool to diagnose defects in combinational logic, to identify defective scan chains, or for statistical data collection during high volume manufacturing to analyze deformations and yield limiters. The presented technique requires no modification to existing scan-based diagnosis tools and has been used in high volume manufacturing flows. The experimental data from production test flows demonstrates its effectiveness for industrial designs