Transient thermal analysis as failure analytical tool in electronic packaging

New packaging technologies are necessary to meet the demand for smaller and more reliable electronic devices. The so-called system-in-package (SiP) concept brings different technologies, material combinations and processes together in one package. To ensure the reliability of such a package reliable, fast and non-destructive failure analysis are needed. Transient thermal methods provide techniques for detection of different types of defects such as delaminations of interfaces, electrical short circuits and voids in die attach layer. We demonstrate the transmission pulse thermography as suitable for in-line inspection of soldered power transistors. No additional coatings are required and the inspection times are in seconds range. By means of Lock-in thermography it was possible to detect internal heat sources of a few μW that causes temperature changes in mK range on the package surface. With simulative studies we predict the possibility to detect internal delaminations of a stacked die 3D QFN package.