Efficient defect identification of soft failures induced by device local mismatch for nano-scale SRAM yield improvement

As the device size continues shrinking to nano-scale region, tiny defects induced device local mismatch in SRAM array becomes a major yield limiter. It is often quite time consuming and challenging to identify such kind of invisible defects through conventional FA techniques. This paper presents an efficient methodology on device local mismatch fault isolation with the combination of test features, advanced Electrical Failure Analysis (EFA) and Physical Failure Analysis (PFA) techniques. A successful case study involving this advanced methodology will be also discussed.