Insights into the Mechanical Properties of SnAgCu Based Solder Materials Including Void Effects: An Atomistic Study

Lead-free Sn-Ag-Cu materials otherwise known as SAC materials are widely used in the electronic packaging industry for its nontoxic nature unlike Sn-Pb solder materials. Electronics in the present world is shrinking components sizes more rapidly than ever, which instigates investigation of solder materials properties at the nanoscale. In our previous work, mechanical properties of SAC solder materials were determined through atomistic simulations. Presence of voids in SAC solder joints is not unusual and at the atomic level, the effect of voids can shape mechanical behavior significantly. In this study, molecular dynamics (MD) simulations have been performed to investigate how the stress-strain behavior of SAC305 solder (at nanoscale) changes with the amount of void present in the material. The percentage of void has been varied from 0 to 20%. In the simulations, the inter-atomic interaction is defined using the modified embedded-atom method (MEAM) potential. In addition to voids, the effects of temperature have also been investigated by changing the temperature from 0 to 125° C. From the obtained results, the correlations between the percentages of void in solder and solder mechanical properties like ultimate tensile strength, yield strength, failure strain, and elastic modulus have been determined for different temperatures. The findings of this study might be helpful in designing and manufacturing of nano-electronic devices.