Study of PCB strains and component position under board level drop test

摘要

Portable electronic products are found to be most susceptible to drop impact during transportation or customer usage. This may induce dynamic bending in the printed circuit board (PCB) and result in component and product failure. The failure rates at these different locations of PCB are monitored so as to understand the relationship between PCB dynamic strains and solder joint failure under drop test. It is found that the dynamic strain of PCB can be used as criteria for assessment of drop impact performance of IC packages during board or product level drop test. With higher strain, the IC package at that location is more likely to fail. It has been found that the drop test failure rate is the highest at the center zone of PCB where the strain is the highest. In this study, the dynamic strain at six locations on a quarter of a JEDEC standard board is also monitored to investigate the drop responses of the PCB. The location where package is most likely to fail is at the center of PCB length edge, where the strain is highest.