Exothermic reaction induced eutectic Pb-Sn solder ball melting in the underfill curing process

The effects of exothermic heat generated during underfill curing on the integrity of the solder bumped package, which is an important issue for the package reliability, have been overlooked. In this study, theoretical exotherm of underfill materials during underfill curing has been calculated using a differential scanning calorimeter (DSC) at cure temperature range from 100/spl deg/C to 200/spl deg/C. The calculated exotherm was compared with the exotherm profile measured at the typical cure temperature. The effects of cure temperature, amount of underfill, and initial underfill curing temperature on the exotherm profile of underfill materials have been investigated.