Investigation of Thermal Characterization of a Thermally Enhanced FC-PBGA Assembly

In this paper, three-dimensional finite element analysis using the commercial ANSYS software is performed to study the thermal performance of a thermally enhanced FC-PBGA (flip-chip plastic ball grid array) assembly in both natural and forced convection environments. The thermally enhanced FC-PBGA assembly is a basic FC-PBGA assembly with a lid attached on top, after which an extruded-fin heatsink is attached on the top of the lid. The finite element model is complete enough to include key elements such as bumps, solder balls, substrate, printed circuit board, extruded-fin heatsink, lid, vias, TIM1 (thermal interface material 1), TIM2 (thermal interface material 2), lid-substrate adhesive and ground planes for both signal and power. Temperature fields are simulated and presented for several package configurations. Thermal resistance is calculated to characterize and compare the thermal performance by considering alternative design parameters of the polymer-based materials and the thermal enhancement components. The polymer-based materials include underfill, TIM1, TIM2, lid-substrate adhesive and substrate core material. The specific thermal enhancement components are the extruded-fin heatsink and the lid.