Thermally-resilient image sensor packaging approach for Mars2020 Enhanced Engineering Cameras

摘要

Electronics designed for NASA planetary missions such as the Martian surface environment require wide-temperature survivable electronics packaging designs to ensure high-reliability avionics and instrumentation. Planetary surface temperature range of −135C to +40C dictate that electronics packaging solutions provide resiliency to large thermal excursions to counteract mismatches in the coefficient of thermal expansion in the myriad of materials found within space born electronics. The Mars2020 Enhanced Engineering Cameras (EECAMs) are a collection of medium- and wide-angle cameras used across the Mar2020 Flight System. The EECAMs use a commercial off the shelf (COTS) image sensor [1] packaged in a 143-pin Ceramic Pin Grid Array (PGA). Early in the EECAM development, breadboard camera electronics that used conventional thru-hole soldering techniques was subjected to limited thermal cycling to investigate packaging survivability in Martian surface thermal environments from −135C to +70C. Functional testing following 2000 cycles showed that the detector was inoperable. Visual inspection of the part exhibited sever solder joint cracking in a substantial number of pins, and in some cases resulted in complete sheering of the pins from the ceramic package substrate. We will present the steps taken to derive the thermally-resilient electronics packaging design of the Mars2020 EECAM detector. We will highlight analyses and empirical test results that lead to a wide-temperature-survivable COTS component packaging design. Details of thermal cycle testing, in-process inspections, and final packaging design will be presented.