Abstract
In case of a node leakage failure in DRAM products, the location of the defect can be spread over the entire deep trench depth of up to six microns, making it very difficult to precisely localize the defects. In addition, the use of surface area enlarging techniques makes it even more difficult to pinpoint the node leakage defect. In this study, first, the node leakage was verified at contact level using the nano-probing technique. In the second step, the sample was deprocessed into the p well level and a current image was obtained, confirming the node leakage to be located below this level. In the third step, the sample was further deprocessed to the edge of the n well level. AFM-based probing provided additional information regarding the location of the node leakage. With these three measurements, the authors confined the node leakage to the small n well region.
