Ball Grid Array (BGA) components are widely used in electronic assemblies. They enable a compact interconnection to be made using solder balls. TWI was keen to understand the long-term integrity of the connecting balls because of concerns over their durability. This Case Study outlines finite element analysis (FEA) work carried out at TWI to investigate the mechanical integrity of the connecting balls.
Finite Element Analysis
A 2D FEA model was constructed. The model represented a diagonal slice, centre to corner, through a 15x15 BGA component. After development of the model it was put through the following thermal profiles:
- Heating that was representative of a reflow soldering operation
- Isothermal cooling modelling the post soldering condition and giving rise to stress relaxation
The benefits of the FEA approach are summarised as follows:
- FEA gives a better understanding of the integrity of the solder connecting balls than can be gained by testing alone. This makes it easier to identify areas to improve the BGA design.
- Using FEA techniques the test programme could be reduced giving cost and time savings.
This work was carried out as part of a TWI research programme to investigate the integrity of BGA components.
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