This research sets up failure analysis flow to verify failure mechanisms and root causes of different kinds of contact leakage. This flow mainly uses EBIC, C-AFM and nano-probing to do fault isolation and confirm electrical failure mechanisms. Appropriate sample preparation is also mandatory for FIB, SEM and TEM inspection.

The result of applying normal xenon ion beam milling combined with patented DX chemistry to delayer state-of-theart commercial-grade 14nm finFETs has been demonstrated in a Helios Plasma FIB DualBeam™. AFM, Conductive-AFM and nano-probing with the Hyperion Atomic Force nanoProber™ were used to confirm the capability of the Helios PFIB DualBeam to delayer samples from metal-6 down to metal-0/local interconnect layer and in under two hours produce a sample that is compatible with the fault isolation, redetection, and characterization capabilities of the AFP. IV (current-voltage) curves were obtained from representative metal-0 contacts exposed by the PFIB+DX delayering process and no degradation to device parameters was uncovered in the experiments that were run. Compared to mechanically delayering samples, the many benefits of using the PFIB+DX process to delayer samples for nano-probing were conclusively demonstrated. Such benefits, include sitespecificity, precise control over the amount of material removed, >100μm square DUT (device under test) area, nm-scale flatness over the DUT area, nm-scale topography between contacts and the surrounding ILD, uniform conductivity across the DUT area, all with no obvious detrimental effects on typical DC device parameters measured by nano-probing.