Die front-end defect isolation case study using a combination of atomic force probing and transmission electron microscopy techniques

As device geometries shrink and operating voltage and current levels keep reducing, conventional Passive Voltage Contrast techniques no longer proves to be effective for the current technology node. In this analysis, a combination of AFP pico-current contrast imaging and nano-probing analysis at the contact layer successfully isolated the defective transistor, where prior contact PVC analysis had been unsuccessful. The real root cause of failure was then revealed by using planar and cross-sectional TEM analysis, which revealed abnormal metal gate and STI profile. For this case study, without the planar TEM analysis, we will missed the real root cause if we decided to cut across the defective transistor.