SRAM cell defect isolation methodology by sub micron probing technique

With the complexity of integrated circuitry and the decreasing size of components, usual isolation techniques (SEM inspections, Passive Voltage Contrast…) are not enough to find the defect. This paper presents an accurate methodology using the Sub Micron Probing (SMP) technique applied to a SRAM cell analysis. Indeed the number of non visual defect (NVD) becomes more and more important on the last technologies. In this context, the classical failure analysis must be improved with the electrical methodology. This method consists in using a quantitative electrical I/V characteristic measurement technique at the metallization, vias, and contacts levels during delayering without physical modification and electrical I/V alteration. Moreover, the efficiency of this methodology allows us to guide analysis and to segregate the failure mechanism.