Drop Shock Testing Analysis at Elevated Temperature: Assessing SAC305 Solder Alloy Reliability in BGA Assemblies

Abstract

The electronics industry is increasingly prioritizing the reliability of SnAgCu (SAC)-based alloys due to environmental concerns related to lead-based alloys. Considering the frequent occurrence of drops during the typical use of portable electronic devices, guaranteeing robust board-level drop shock reliability becomes vital for ensuring their optimal performance and longevity. Traditionally, drop shock tests have predominantly been conducted at room temperature, which does not fully simulate real-world conditions where electronic circuits are subjected to operational or environmental thermal strains during the normal operation. To address this knowledge gap, this study aims to conduct drop shock tests at elevated temperatures, ensuring the reliability of solder joints in practical applications. In this study, ball grid array (BGA) assemblies containing SAC305 solder alloy were tested at various temperatures. The drop shock experiments were performed according to the Joint Electron Device Engineering Council (JEDEC) drop test standard JESD22- B111A, with a peak acceleration of 1500 G and a pulse duration of 0.5 ms. Subsequently, the drop shock reliability of the solder joints under each test condition was assessed using the Weibull analysis. In addition, the Arrhenius model was applied to develop a drop life prediction model. Furthermore, comprehensive microscopy analysis was performed to identify the failure modes and trends with increasing temperature. The results indicated that SAC305 exhibits best performance at room temperature (25 ° C). However, its drop shock lifespan significantly decreases as the temperature rises, with reductions of 64%, 76%, and 78% at 50 ° C, 75 ° C, and 100 ° C, respectively. Moreover, a failure mode transition was observed with an increase in temperature.