Abstract
This paper places a strong emphasis on the importance of applying the correct FA approach in physical sample preparation to identify hidden defects that can be easily removed during analysis. A combination of mechanical parallel polishing and chemical etching was used during the sample preparation after electrical fault isolation. Such a combination is both effective and efficient in identifying the single Via punch-through from a sea of Via in MIM structure as well as finding the thin layer of barrier bridging under the Al metal. It serves as a quick way to verify any suspect without time consuming FIB progressive cuts at the hotspot location which sometimes turns out to be an induced spot with a defect located at other site due to the circuitry connection. It would serve as a good reference to wafer fab that encountered such issues.
