The study of dynamic dispensing pattern effects on capillary driven underfill process

Abstract

In the present days where technology has become one of the must have items by our community, the needs of reliable electronic packaging has become crucial. This work presents the effect of different dispensing patterns on capillary driven underfill process namely I, L and U pattern in flip chip packaging. In this study, the real dynamic dispensing system that had been applied in underfilling process was simulated with a three-dimensional flip chip model that was constructed using SolidWorks and modelled using ANSYS FLUENT. As modelled, underfill material of 0.3 Pa.s viscosity was injected into a 1 mm gap of a 30x30 mm flip chip with full ball grid array package. The injection time was fixed at 3 s for all three dispensing patterns. The result obtained showed that the U pattern filled the gap the fastest followed by L pattern and I pattern but L pattern is the best due to its relatively low filling time and less void formation.