Identification of Subtle Defect by Means of High Kev SEM Passive Voltage Contrast

This paper presents two cases utilizing high KeV Passive Voltage Contrast (PVC) for defect localization that is impossible with other techniques. The first case is thin layer resistor of CrSi. De-processing or polishing to expose the defective layer may damage it. High KeV PVC combined with FIB etch allows for a clear top view and x-section image. The second case involves a beam sensitive via chain. In order to avoid ion-beam-caused-damage, carbon paste was used to ground the sample. A high KeV electron beam was used to localize the defective via. This paper also discusses the way to avoid beam caused sample damage and how to apply it for further grounding and FIB cross sectioning to reveal the defect.