Green interconnecting materials for semiconductor industry

Interconnecting materials experience a complex thermo-mechanical load in applications. This may lead to the formation of macroscopic cracks resulting from induced stresses of the differences in thermal expansion coefficients on a sample scale (since different materials are involved) and on a grain scale (determined by the Sn anisotropy). Moreover, the grain structure of an interconnection may change due to tin-pest formation. In the replacement of classical tin-lead alloy by green alternative materials, Sn anisotropy and tin-pest are posing a crucial challenge to semiconductor industry. In this paper, it has been summarized from a comparative study employing a combination of experimental and finite element calculations of pure Sn and a Sn-3.8Ag-0.7Cu (SAC) alloy that significant contribution to encountered fatigue damage stems from the thermal anisotropy of Sn. Tin-pest has also been confirmed to form in pure Sn but its formation is ruled out in SAC alloy within the span of time duration of experiments. Based on our findings, some potential suggestions are given that would enhance the existing knowledge on the impact of replacing tin-lead alloys for practical industrial applications a significant step forward to the microelectronics industry.