Board level solder joint analysis of ball grid array package under drop test using finite element methods

ABSTRACT

Handheld electronic devices are vulnerable to drop impacts, leading to mechanical damage and electrical failures such as PCB cracking, trace damage, solder joint fractures, and component breakage. This study investigates the reliability of solder joints in Ball Grid Array (BGA) packages by examining their dynamic response under board-level drop impacts using Finite Element methods. Explicit dynamic analysis employing the Input-G method, in accordance with JEDEC guidelines, was used to simulate the printed circuit board assembly (PCBA) model. Results reveal that solder balls on the board side are more critical than those on the package side, with corner-most solder balls near the board edges identified as the most vulnerable, experiencing maximum peel stress of 162.12 MPa and strain of 0.001048. Analysis of radial displacement and drop orientation showed that BGA packages positioned closer to PCB edges exhibit greater reliability than those at the centre. The face-down drop orientation was identified as the most vulnerable configuration. Structural optimization of the PCBA, incorporating factors such as solder ball pitch, PCB thickness, and solder ball diameter, significantly improves reliability, underscoring the importance of these parameters in ensuring the long-term durability of the assembly.

Keywords:
Board level reliability; BGA package; Surface Mount Technology (SMT); Parametric Analysis; Drop Test; Solder ball