Predicting the movement of voids in solder bumps and subsequent reliability

This paper describes modelling technology and its use in providing data gov erning the assembly and subsequent reliability of electronic chip component s on printed circuit boards (PCB's). Products, such as mobile phones, camco rders, intelligent displays, etc, are changing at a tremendous rate where n ewer technologies are increasingly being applied to satisfy the demands for smaller products with increased functionality. At ever decreasing dimensio ns, and increasing number of input/output connections, the design of these components, in terms of dimensions and materials used, is playing a key rol e in determining the reliability of the final assembly. Multiphysics modell ing techniques are being adopted to predict a range of interacting physics- based phenomena associated with this manufacturing process. For example hea t transfer, solidification, marangoni fluid flow, void movement, and therma l-stress. The modelling techniques used are based on finite volume methods that conserve the physics and take advantage of being able to represent the physical domain using an unstructured mesh. These techniques are also bein g used to provide data on thermal induced fatigue which is then mapped into product lifetime predictions.