Study on Dipping Mathematical Models for the Solder Flip-Chip Bonding in Microelectronics Packaging

In order to develop the flux dipping process, a quantitative mathematical model that accurately describes the flux dipping process in the flip-chip bonding is proposed. The whole dynamic dipping process is captured by the high-speed transient imaging followed by image processing. Curve fitting of experimental results yields the relation between flux dipping quantity and process parameters. It suggests a quadratic function of quantity (Q) with respect to dipping depth (d), and a piece-wise function to dipping speed (v) including an exponential section and a quadratic or linear section. While the coupled effect of d and v can be expressed as a merged function of Q = f((d,v)), these mathematical models are proved to be effective when applied to the actual dipping process practiced on a flip-chip bonding machine, thus providing a reliable mathematical basis for optimizing dipping flux in industrial manufacturing.