MODELS FOR RELIABILITY OF FINE-PITCH BGA'S AND CSP'S IN SHOCK AND DROP IMPACT

摘要

Drop-induced failures are most dominant in portable electronic products. In this study, explicit finite element models have been used to study the transient dynamics of printed circuit boards during drop from 6ft. Methodologies for modeling components using smeared property formulations have been investigated. Reduced integration element formulations examined include - shell and solid elements. Model predictions have been validated with experimental data. Results show that models with smeared properties can predict transient-dynamic response of board assemblies in drop-impact, fairly accurately. High-speed data acquisition system has been used to capture in-situ strain, continuity and acceleration data in excess of 1 million samples per second. Ultra high-speed video at 40,000 fps per second has been used to capture the deformation kinematics. Component types examined include -plastic ball-grid arrays, tape-array BGA, QFN, and C2BGA. Model predictions have been correlated with experimental data. Impact of experimental error sources on model correlation with experiments also has been investigated.