Abstract
The main objective of this work is to study the heat dissipation mechanism of the board-level Plastic Ball Grid Array (PBGA) electronic packaging. Under a natural convection environment, the majority of the thermal dissipation of the board-level PBGA package is first conducted to Printed Circuit Board (PCB) and then carried through the PCB surface by convection and radiation. Therefore, the thermal performance of the board-level PBGA package is significantly dominated by the way of chip power dissipation conducted to PCB and different structural design of PCB. Besides, due to the complicated structure of PCB, a simple but accurate equivalent PCB thermal analysis model is also tackle in this work to reduce the product design process.In this work, a detailed three-dimensional finite element model of the board-level PBGA package is first established as a benchmark using ANSYS finite element analysis program. The infrared (IR) thermography and thermal test die experiments are also performed to validate the benchmark finite element analysis model. Then, based on the established benchmark analysis model, the influences of various design parameters of PCB structure on the thermal performance are thoroughly studied, including the number and location of embedded copper layers, thickness of top signal layer and presence of thermal vias etc. The effects of number and allocation of thermal solder balls welded on PBGA package and thermal vias within BT-substrate on the thermal performance of the board-level PBGA package are also investigated in details. Finally, the efficiency of the established equivalent PCB thermal analysis model in this work is also evaluated. In addition of academic contributions, the results obtained would be of help for electronic packaging industry to perform thermal enhancement design of products.