Dynamic Mechanical and Failure Properties of Solder Joints

Abstract

Solder joints are widely used as interconnections in electronic components, such as the ball grid arrays (BGA) in advanced electronic packaging. Arising from the continuous push for device miniaturization and new applications in portable electronics, solder joint failure under drop or shock conditions is becoming a critical issue. However, studies of solder joints under dynamic loading are limited, especially for lead-free solders. The objective of this study is to investigate the load-deformation response and failure characteristics of lead-free solder joints in BGA packages under quasi-static and dynamic/impact loading. Appropriate methodologies for preparation and testing of single solder joint specimens under quasi-static and dynamic loading were established. Especially, a miniature impact tester was proposed and validated for dynamic testing of small specimens. Load-deformation curves of solder joints under combined normal/shear loads were obtained and characterized, and failure force envelopes were constructed and formulated. Numerical models for solder joints were investigated and compared, and the equivalent stress-strain responses of solder joints were derived. Finally, the beam element was applied in FEM simulation for solder joints in board-level specimens subjected to quasi-static bend and dynamic drop testing.