Qualification of flip chip fluxes by wetting balance and surface insulation resistance tests Available to Purchase

Owing to the incessant demand for reductions in the size of portable electronics, new dense packaging technologies are required. Reflow soldering is still mainly used for component joining on the substrate. In tiny joints such as those in flip chip (FC) assemblies the flux effect is vitally important and needs to pass a narrower performance window than in ordinary surface mount technology (SMT). The determination of the suitability of a flux, as reported in this paper, is twofold; first, the flux must perform well in its intended purpose and second, the flux must not leave harmful residues causing leakage or electromigration. The first test used was the wetting balance test for all fluxes. Fluxes accepted on the basis of the wetting tests were then subjected to the surface insulation resistance test (SIR).