Board Reflow Processes and their Effect on Tin Whisker Growth

This chapter reviews the potential affect that the board reflow process has on tin whisker growth. Investigations in this area have looked at grain orientations and grain size, solder paste volume, and solder peak temperature on tin whisker growth. The chapter discusses the results on tin whisker testing on soldered pure‐tin‐coated components after reflow. There has been work to understand the affect of reflow profile, reflow atmosphere, solder paste volume, and flux activity on tin whisker growth. For tin‐lead soldering, the lower soldering peak temperature reduced solder paste wetting up the component lead frame increasing the potential for tin whisker growth. Different flux activators were found to aid the oxidation of tin, which increased tin whisker growth after temperature and humidity testing. Increased contamination of the soldered components with chloride and sulfate also increased tin whisker growth after temperature and humidity testing.