A low-temperature Pb-free soldering solution for high power density power electronics is discussed. To this point, a trade-off between cost, complexity, and performance has been required when designing in a thermal management/mechanical attach solution for power modules. A SAC-In alloy solution is presented in a solder preform configuration that can be used with reflow temperatures below that of industry standard lead-free and/or high temp. solders. This alloy is a drop-in replacement relative to existing soldering processes and offers improved thermal performance beyond organic-based thermal management solutions (e.g., thermal grease, silicones, PCM’s). In addition to these benefits, a peak reflow temperature below ~215 ° removes the risk of damage to components and materials in molded package power modules, mitigates warpage/material stress issues during the soldering process, and reduces energy consumption. This Bi-free alloy offers mechanical properties and ductility that contribute to robust lifecycle performance comparable to standard Pb-free alloys as shown by thermal shock testing -40°/+125°C.
