Impact of Thermomechanical Fatigue and Creep on the Reliability of BGA Lead-Free Solder Joints in Electronic Modules

Ball grid array (BGA) packages, crucial in modern electronics, have significant potential to promote sustainable manufacturing. However, the reliability of BGAs using lead-free tin-silver-copper (SAC) solder alloys needs full qualification, particularly for mission-critical applications. This study examines the thermomechanical fatigue and creep responses of Sn63Pb37, SAC305, SAC387, SAC396, and SAC405 solder joints in BGA packages under thermal cycling, using finite element analysis (FEA) with Garofalo's hyperbolic sine law for solder material behavior. SAC387 and SAC405 alloys exhibited promising properties, making them strong candidates as alternatives to the traditional Sn63Pb37 solder. As per the results, SAC387 demonstrated the greatest stiffness and resistance to elastic deformation, though it showed a higher susceptibility to creep compared to other alloys. SAC405 emerged as the most durable, exhibiting minimal plastic deformation and strain under thermal stress, making it ideal for resisting failure. The critical areas for crack initiation and propagation were identified at the interfaces between the solder and both the chip and substrate. These findings align with existing research, highlighting key factors in the reliability of solder joints under thermal cycling and creep.