Drop performance evaluation for application of different underfill processes

As drop-induced failures are most dominant in handheld electronic products, enhancing the anti-dropping performance of fine-pitch ball grid array (FBGA) package, which are currently popular in handheld electronic products is very important. In this paper, the anti-dropping performance of Fine-Pitch BGA package is evaluated with respect to their solder joint reliabilities after drop impacts test experiment and drop test simulations. The drop test procedure and conditions are based on the JEDEC standard. As underfill is generally used at SMT level to improve mechanical property and reliability of electronic product and different underfill processes and different underfill structures will affect the mechanical strength of the solder joint. The effect of several underfill processes including the use of solder joint encapsulant adhesives, package with generic epoxy underfill were investigated. Results show that structure of the fully reinforced solder joints formed by the traditional underfill process underfill have a better anti-drop performance than the partially reinforced solder joints structure formed by solder joint encapsulant underfill process.