Reflow Profiling for Next-Generation Solder Alloys

Abstract: After the Pb-free transition, most of the industry settled on using predominantly SAC305 solders. More than a decade later, a large segment of the industry is moving to adopt modified SAC alloys, as well as new Pb-free alloys for higher reliability, or even low melting point alloys. These choices really expand the playbook of possible reflow profiles.

This paper will review common profile shapes and recipes, showing data for how they differ in the resulting solder joints. There will also be a discussion on the critical points of successful reflow profiling for the wider range of Pb-free alloys now on the market.

In addition, as high-temperature applications that traditionally used high-Pb alloys for high operating temperatures come close to losing RoHS exemptions, new alloys are emerging to achieve the high performance expectations associated with applications in this range.