With the evolution of advanced process technology, failure analysis has become more and more difficult because more defects are of the non-visual type (very tiny or even invisible defects) from new failure mechanisms. In this article, a novel and effective methodology which couples the conductive atomic force microscope (C-AFM) with nano-probing technique is proposed to reveal some particular failure modes which were not observable and difficult to identify with traditional physical failure analysis techniques. The capability of coupling C-AFM with nano-probing technique is used to distinguish cases which suffer general junction leakage or gate leakage from those that form the fake junction leakage or gate leakage cases. C-AFM can detect the abnormal contacts quickly, and nano-probing could provide the precise electrical characteristic further. Then, combining these variant measuring results, the favorable tactics can be adopted to deal with different states.

This paper presents a novel deductive methodology, which is accomplished by applying difference analysis to nano-probing technique. In order to prove the novel methodology, the specimens with 90nm process and soft failures were chosen for the experiment. The objective is to overcome the difficulty in detecting non-visual, erratic, and complex failure modes. And the original idea of this deductive method is based on the complete measurement of electrical characteristic by nano-probing and difference analysis. The capability to distinguish erratic and invisible defect was proven, even when the compound and complicated failure mode resulted in a puzzling characteristic.