Reliability Assessment of Advanced Flip-Chip Interconnect Electronic Package Assemblies under Extreme Cold Temperatures (−190 and −120°C)

Flip-chip interconnect electronic package boards have been assembled, underfilled, non-destructively evaluated, and subsequently subjected to extreme temperature thermal cycling to assess the reliability of this advanced packaging interconnect technology for future deep-space, long-term, extreme temperature missions. In this very preliminary study, the employed temperature range covers military specifications (−55 to 100°C), extreme cold Martian (−120 to 115°C) and asteroid Nereus (−180 to 25°C) environments. The resistance of daisy-chained, flip-chip interconnects was measured at room temperature and at various intervals as a function of extreme temperature thermal cycling. Electrical resistance measurements are reported and the tests to date have not shown significant change in resistance as a function of extreme temperature thermal cycling. However, the change in interconnect resistance becomes more noticeable with increasing number of thermal cycles. Further research work has been carried out to understand the reliability of flip-chip interconnect packages under extreme temperature applications (−190 to 85°C) via continuously monitoring the daisy chain resistance. Adaptation of suitable diagnostic techniques to identify the failure mechanisms is in progress. This paper will describe the experimental test results of flip-chip testing under extreme temperatures.