
Wire bonding breakage failure mechanism analysis in photodiode allowing for lifetime prediction
In the context of the iRel40 project, BSH Electrodomésticos España (BSHE) has studied the wire bonding breakage failure mechanism of a photodiode that integrates its induction cooktops, which is a consequence of applying strong thermal cycling. BSHE has performed an accelerated test consisting of the application of thermal cycling on the wire bonding/chip to test breakage, using the “Coffin-Manson equation” to determine the acceleration factor. The testing and a subsequent study of X-Ray spectroscopy and microscope filter images of the failed samples have allowed us to conclude that the failure is caused by the mismatch of coefficients of thermal expansion between the wire, the mold compound, and the silicon, causing a stress that the component is not capable to withstand. This conclusion has allowed BSHE to better define the factors that participate in the Coffin-Manson equation and thus be able to obtain a more accurate model for the estimation of the remaining useful life of this component. In addition, this has provided insights for the component’s supplier in order to develop a more robust and reliable component design and manufacturing process.