Reliability Enhancement of Automotive Electronic Modules Using Various Glues

Several types of glues are applied to fcBGA on the board level in order to enhance the reliability of PCB assembly to meet harsh automotive conditions. This paper describes a series of mechanical and thermal stress tests using a printed circuit board (PCB) for automotive applications. FEA and experimental results show that corner fill may be a better choice in handling both mechanical and thermal stresses. All glues tested have shown improvement on the mechanical stress but not every glue can improve the thermal cycling reliability of solder joints. Results also show that underfill may not have the same performance as compared to corner fill for this application and is hereby not recommended.