The low melting temperature of 138°C makes SnBi alloys attractive for assembling thermally warpage-prone high-density microelectronic packaging. However, Bi has a high propensity for electromigration and segregation at the anode under high current density conditions. This can lead to potentially brittle solder joints with high electrical resistance over time in the field. There is need to explore ways to mitigate such shortcoming and develop SnBi solder joints that maintain their performance and reliability over the product life. This iNEMI project plans to explore the potential to reduce electromigration in low height solder joints by taking advantage of mechanical and/or chemical back stresses. 

Objective