The aim of this paper is to describe a failure analysis methodology applicable to reveal
the root causes of electronic assembly failures. The most relevant properties of the applied
techniques, i.e. optical microscopy, X-ray microstructure analysis, SEM (scanning electron
microscopy) combined with EDX (energy dispersive X-ray spectroscopy) analysis, are given. Three
recent failure analysis case studies are also presented. In case of a burnt component the microwire
and the leadframe formed AlCu intermetallic compound in the length of several millimeters. The
low joint strength of gullwing leads were deduced back to paste printing and wetting problems. The
fracture surface morphology of a joint broken on the field showed different structure from the ones
broken at room temperature. It was revealed that SnPb solder fracture surface is different at room
temperature and above 100°C.
