Reliability analysis of PBGA lead-free interconnect solder joints under drop impact load

Purpose The development of electronic components has been characterised by a reduction in size and an increase in weight. Drop impact loading has become a primary cause of failure in contemporary portable electronics. Solder joints, as mechanical, electrical and heat dissipation components, its reliability in service is highly dependent on intermetallic compounds (IMC). Design/methodology/approach In this paper, IMC samples were prepared for the purpose of empirical investigation. The growth patterns and material parameters of the IMC layer at different ageing times were obtained through the use of scanning electron microscopy and nanoindentation technology. The experimental data were amalgamated with finite element simulation to establish a Plastic Ball Grid Array (PBGA) packaging model, incorporating the IMC layer. The present study investigates the reliability of interconnection solder joints under board-level drop conditions, using a range of IMC layer thickness values and three distinct types of lead-free solder. Findings The findings indicate that as the thickness of the IMC layer increases, the maximum peeling stress value of the critical solder joints also increases. Further, the difference between the maximum peeling stress value when the thickness of the IMC layer is 2 µm∼19 µm and when the IMC layer is not taken into account is 31.4∼103.2 MPa. In the case of the three types of lead-free solder joints, taking into account the presence of the internal IMC layer, it was demonstrated that Sn3.5Ag solder joints exhibited a superior capacity to resist drop impact loads. Originality/value The findings of the research have provided a theoretical foundation for the practical field of electronic packaging engineering.