Reliability of BGA solder joints using nanoindentation

Abstract The reliability of electronic packaging primarily relies on the thermomechanical properties of solder joints. In the study of solder joint reliability, it is crucial to establish accurate constitutive equations. The parameters required by the constitutive equations are typically derived from uniaxial tensile experiments conducted on bulk solder specimens. To limit the size effects of Sn-Ag-Cu (SAC) solder, a method based on high-temperature nanoindentation creep data of actual SAC solder joints is proposed to extract the parameters of the Anand constitutive equations. Additionally, finite element analysis (FEA) is employed to simulate the stress response of ball grid array (BGA) packaging components under thermal cycling loads. The study reveals that the maximum equivalent stress and variation range of the stress in BGA solder joints based on constitutive equations using nanoindentation (CEUN) are greater than those based on constitutive equations using uniaxial tension (CEUUT). This study indicates that the actual working life of solder joints may be lower than the predicted results based on traditional CEUUT method.