Predictive reliability assessment and failure rate modeling for electronic packages

The certification methodology in use for today's package technologies would not characterize the reliability and failure rates well. The failure data could be processed wrongly or not correlated to the failures in the field application. The test condition and duration of standard accelerated stress tests, such as those found in MIL-883 or JEDEC standards, were not designed to collect the statistically significant failure data. Instead, the desired testing result was a zero failure. A physics-based reliability modeling approach would help yield a complete model to obtain the life projection and the failure rate prediction in the field. The model would be more objective and help response to the rapidly developing market demands. Case studies of the reliability tests demonstrated the needs for the physics-based technology qualification approach. They revealed that a constant failure rate often observed for the package reliability. The key package failures were often defect driven and random. It was appropriate to use constant failure rate approach for the package reliability analysis. The failure rate model approach using the error bound at certain time interval was more realistic than traditional Chi-square approach when the failures were random. The calculation of AF for multiple failure mechanisms was discussed in the article as well.