Mechanical Characterization of Power Electronics Solder Materials

One of the main bottleneck for power semiconductor durability is the solder joint reliability. A proper design of the interconnections between silicon chip and printed control board is needed to fulfill the strict industrial and automotive requirements. Considering that solders are alloys with melting temperature lower than 450∘C, high-temperature package processes and costumer profile condition enhances the visco-plastic solder degradation, affecting the joint dimensional tolerances and reliability. The mechanical characterization of solder compounds and processes results fundamental to achieve reliability and geometric dimensioning and tolerancing targets. The presented work proposes an analytical-experimental methodology to characterize the mechanical constitutive equation of a specific solder compound widely used in semiconductor industries that is SnAgCu. Visco-plastic solder behavior with respect to environment temperature is experimental detected employing different uniaxial tensile tests considering some scenarios in terms of strain rate and temperature conditions. These outcomes are numerically post-processed to find out the Anand parameters of the analyzed solder according.