Application of Electrical Diagnosis and C-AFM to Isolate on Board AC Scan Fail

With the migration from deep submicron process to today´s nanometer-scale process, speed-related defect begin to dominate the yield loss. The path delay now is the predominant failure, especially when device is on board test. Traditional localization approaches, such as EMMI (emission microscope), OBIRCH (optical beam induced resistance change), TIVA (thermal induced voltage alternation), MCT(HdCdTe) camera etc are hard to detect subtle delays or isolate them correctly. In this paper, we succeeded in applying electrical diagnosis and C-AFM (conductive atomic force microscope) skill to isolate on board AC scan fail. This technique is effective of scan-based AC tests, particularly those exhibiting delay faults