Predicting the movement of voids in solder bumps and subsequent reliability [flip chip assembly]

This paper describes modelling technology and its use in providing data governing the assembly and subsequent reliability of electronic chip components on printed circuit boards (PCBs). Products such as mobile phones, camcorders, intelligent displays, etc., are changing at a tremendous rate, where newer technologies are increasingly being applied to satisfy demands for smaller products with increased functionality. At ever decreasing dimensions, and increasing number of input/output connections, the design of these components, in terms of dimensions and materials used, is playing a key role in determining the final assembly reliability. Multiphysics modelling techniques are being adopted to predict a range of interacting physics-based phenomena associated with this manufacturing process. For example heat transfer, solidification, Marangoni fluid flow, void movement, and thermal 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 being used to provide data on thermally induced fatigue, which is then mapped into product lifetime predictions