Application of voltage and waveform forcing method for electrical isolation of complex and loop circuit in failure analysis

With multi-metal layers and scaling down we occurred many difficulties in FA. Due to coverage of metal layers precise emission spots and hotspots were not captured and sometimes many test points were planted Pt probe pad to perform failure isolation difficultly. So, some new technologies for FA were developed in recent years, for example NAIL, and laser voltage probing and so on. In this paper, we propose a method for complex and loop circuit in electrical failure isolation. The main ideas of forcing method were the simulation experiment on reference and fail parts for complex or loop circuit. Voltage and waveform were forced on some test points and the other signal was monitored. According to measured result, we could conclude the root cause was isolated on which signal. We shared three real successful cases with applying forcing method. So, we believed the advantages of forcing method were novel, effective and low cost. It was beneficial to our FA for complex and loop circuit in electrical failure isolation.