Superconducting Quantium Interferance Device (SQUID) microscopy uses detection of magnetic fields to image current paths within electronic devices and has been successful in non-destructively identifying the location of low leakage currents, even when the failure site was between a power and ground plane. This article presents a case study in which the customer was experiencing ignition of a 20-layer printed circuit board after approximately 1000 to 4000 operating hours in an indoor-controlled environment. High currents on the board resulted in extensive damage, effectively preventing initial identification of the failure site, failure mechanism, or root-cause. Based on a review of potential failure mechanisms, measurement of relevant parameters, and the results of SQUID microscopy, the process of electrochemical migration around or through the particles was determined to be the most likely root-cause of electrical shorting between power and ground.

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