One challenge in failure analysis of microelectronic devices is the localization and root cause finding of leakage currents in passives. In this case study we present a successful approach for failure analysis of a diode leakage failure. An analytical flow will be introduced, which contains standard techniques as well as SQUID (superconducting quantum interference device) scanning magnetic microscopy and ToFSIMS as key methods for localization and root cause identification. [1]