Detection of Corrosion in Thick Film Resistors by X-Ray Imaging

In this article, a non-destructive method is presented, using 2D X-ray imaging, to investigate corrosion defects in thick film resistors stressed by two different corrosion experiments, a single gas experiment and a flowers of sulphur experiment. In total, 370 devices under test (DUTs) were investigated, using the 2D X-ray imaging technique, of which 10 were imaged in a sequence of 2D X-ray images to evaluate the corrosion propagation. The observed underlying corrosion product was verified by using focused ion beam analysis combined with an energy dispersive X-ray spectroscopy. The presented 2D X-ray imaging technique enables a fast and non-destructive method for accurately identifying corrosion and corrosion progression in thick film resistors. The presented imaging method was found to be particularly suitable for supplier benchmarking purposes, as well as for the failure analysis of field returns as it allows for a proper corrosion evaluation of surface mount thick film resistors, while keeping the analysed assembly intact.