Simulation of Dynamic Recrystallization in Solder Interconnections during Thermal Cycling

Solder alloys are widely used bonding materials in electronics industry. The reliability con‐ cerns for solder interconnections, which provide both mechanical and electronic connec‐ tions, are rising with the increasing use of highly integrated components in portable electronic products [1-6]. As shown in Fig. 1, a typical ball grid array (BGA) component board usually consists of a silicone die, molding compound, solder interconnections, and printed wiring board (PWB). In service, all products are subjected to thermal cycles as a re‐ sult of temperature changes due to component internal heat dissipation or ambient tempera‐ ture changes. The existence of coefficient of thermal expansion (CTE) mismatches between dissimilar materials (about 16 ppm/°C for PWB and 2.5 ppm/°C for Si die [7]) is the source of deformation and thermomechanical stress in the solder interconnection, which leads to the cracking of the interconnections and failures of the electronic devices.