Failure analysis on the low output power abnormity of a microsystem during the thermal cycle

Failure location and mechanism analysis about a microsystem fault is presented in this work. The fault phenomenon of abnormal low output power amplitude appears only at low temperature during thermal cycle test. A series of analysis including internal fault location and replacing parts for validation help to find the fault origin: a line winding inductor. The failure mechanism of the failed inductor is analyzed by optical microscope, X-ray inspection, scanning electron microscope, energy spectrum analysis and so on. It is found that the enameled wire of the abnormal inductor is damaged during the installation process and the crack develops under thermal cyclic stress. By summarizing the analysis process and the test result, the investigation can provide reference for the failure analysis of similar microsystems.