Advanced Laser Probe Techniques Applied to FA of RF Integrated Circuits - A Case Study

Failure analysis of RFIC’s can be a challenging problem, particularly as frequencies ascend into the medium to high GHz region. As frequency goes up, active probes become less and less accurate due to capacitive loading of circuit nodes, and capacitive coupling of stray signals into the probe from nearby circuit traces. We have found that Laser Voltage Imaging (LVi) offers an alternative measurement technique that can avoid these problems. But our work also showed that there are unusual failure signatures which appear as signal frequencies go up. A combination of LVI and RF-SDL was found to yield the best result.