Solder Joint Reliability in Extreme Thermal Cycling

Abstract

Electronics that operate at low temperatures are necessary for image sensors; exploration of our moon and the moons of Jupiter; and the Large Hadron Collider at CERN. Electronics in these applications are expected to thermal cycle between room temperature and 4-50K depending on the application. Testing the reliability of solder joints used in the fabrication of electronic modules by thermal cycling is necessary to predict the reliability of the electronic system. This project explores the durability of different components soldered on a printed circuit board through thermal cycling. The components are connected to create electrically continuous daisy chains. A solder joint failure will ‘open’ the electrical daisy chain, which can be easily detected by the monitoring software developed for this project.

Cycling will range from room temperature (293K) to liquid helium temperatures (4.2 K) using a cryogenic cooler. Using a closed-loop helium system, a cold plate is cooled to <4.2 K. Resistors mounted on one side of the cold plate are used to resistively heat the plate back to room temperature, creating the thermal cycle. The printed circuit boards are thermally connected to the cold plate. Control software has been developed to control the thermal cycling profile.

The test will continue until at least 50% of the solder joints have failed. It is estimated the test will run 6-12 months.