<p>During operations, handling, and storage in extreme environmental applications like download drilling, aerospace and vehicles, electronics will undergo high and low operating temperatures. In electronic assemblies, temperature generally depends on position, dissipation of energy, and thermal architecture. In automotive under hood applications, the temperature can vary especially from -65 to +200 °C. In the case of automotive electronics which are under hood, on&nbsp;the engine driver interior, and in the ECU box, some investigators have shown that the required operating temperature is between -40 and 200 °C [Eddy 1998, Hattori 1999, Johnson 2004 &amp; Watson 2012]. Under different thermal loads, lead free solder materials continue to evolve. The material properties may be degraded whether the working conditions are poor or heavy. Nonetheless, lead free&nbsp;solders are durable and brittle, meaning that solder joints are more prone to heavy strains that can lead to electronic devices failure. We need stronger solder alloy, which can withstand harsh conditions. &nbsp; We need a greater understanding of solder alloy to design and enhance the efficiency of electronic devices. New doped SAC solder alloys have recently been produced with the addition of Ni, Co, Au, P, Ga, Cu and Sb to SAC solder alloy to boost the mechanical properties, thermal properties, etc. Adding Bi to traditional SAC solder alloys can improve properties such as wettability, melting point, microstructure, and shock &amp; drop response. Recently, SAC-Q are formulated with Sn-Ag-Cu with addition of Bi (SAC+Bi). The previous research investigated the evolution of anand parameters and materials properties for SAC solder (SAC105, SAC305 and SAC-Q) at high temperatures and high strain rates. It was observed that the addition of dopants in SAC alloys may help improve mechanical properties and minimize deterioration due to aging. However, data on SAC solder alloys after prolonged storage at high strain rate, at low operating temperatures are not available in published literature. In this paper, materials characterization of SAC (SAC105 and SAC-Q) solder after prolonged storage at low operating temperatures (-65°C-0°C) and at high strain rates (10-75 per sec) has been studied. The fabricated SAC leadfree solder specimens were isothermally aged up to 12 months at 50°C before testing. Anand Viscoplastic model has been used to compute 9 anand parameters from measured Tensile data to describe the material constitutive behavior. Evolution of Anand Model parameters due to thermal aging has been studied. The computed 9 anand parameters were used to verify the accuracy of the Anand model. A good correlation was found between experimental data and Anand predicted data.</p>

Low Temperature Material Characterization of Lead-Free SAC Solder Alloy at High Strain Rate After Prolonged High Temperature Storage

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2021/volume/85505

ASME 2021 International Electronic Packaging Technical Conference and Exhibition (InterPACK2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.