Corrosion behavior and failure mechanism of ball grid array packages in fire smoke atmospheres

Abstract

Ball grid array (BGA) packages is a common type of electronic packaging and a crucial component in electronic devices. However, its reliability is significantly compromised when exposed to fire smoke atmospheres, thereby reducing the overall reliability of electronic equipment. Therefore, the study of failure mechanisms of BGA packages in fire smoke environments is of paramount importance for the recovery and maintenance of electronic devices post-fire. In this study, we conducted fire smoke experiments and employed electrical performance measurements along with chemical characterization techniques to delve into the failure behaviors and mechanisms of BGA packages in different fire smoke atmosphere. The results reveal that nitrile-butadiene rubber and polycarbonate smoke do not affect the electrical conductivity of BGA packages. However, the accumulation of smoke particles and water between the interconnecting solder joints temporarily reduces the insulation performance. That is induced by the deposition of smoke particles and can be restored after cleaning. On the other hand, under polyvinyl chloride smoke, BGA packages experiences insulation failure and permanent open-circuit failure. This irreversible permanent open-circuit failure is caused by the interconnection of corrosion products in solder joints. Chemical characterization analysis results indicate that solder joints dissolve due to the galvanic corrosion mechanism, transforming the solder from a spherical shape into a rose-like structure. The corrosion products primarily consist of flake-like SnO and Sn3O(OH)2Cl2. This research contributes to a deeper understanding of the failure mechanisms of electronic devices in fire smoke and provides essential guidance for post-fire equipment maintenance.