New approach for High Reliable & Cost-Effective Solder alloys for Automotive Applications

Abstract Commercially known as Innolot, the highly reliable lead-free alloy, allowing for high operating temperatures, is a Tin-Silver-Copper (SAC) metallurgical system with additional elements to harden alloy and improve its creep strength in order significantly reliability of solder joints. Compared traditional SAC alloys, characteristic lifetime can be enhanced on base temperature cycle tests (TCT) from −40°C +125°C or even extended 150°C. Assemblies automotive industry increasingly require higher safety relevant emerging applications such Advanced Driver Assistance Systems (ADAS). Cost-reduction requirements demand new approach optimized soldering processes materials. As current reflow process prefers Nitrogen atmosphere low defects soldering, our research focuses around partial and/or complete change air processes. Furthermore, we investigate influence different surface finishes Chemical Sn, NiAu, Cu OSP, modified compositions performance. Apart initial characterizations various assemblies, Heraeus Reliability1 printed circuit boards well −40 +150°C up 2500 cycles are reported resulting failure modes discussed. This paper furthermore describes potential cost reductions via material optimizations without diminishing performance applications.