Real-time popcorn analysis of plastic ball grid array packages during solder reflow

The time-history deformation of plastic ball grid array (PBGA) packages during solder reflow on printed circuit boards (PCB) is measured by the electrical-resistance strain gauge method. Two groups of experiments are performed, one after 24 hours at 125/spl deg/C (to bake out the moisture from the package) and the other after 24 hours at 125/spl deg/C, then 85/spl deg/C/85RH for 168 hours (to impose a controlled moisture content into the package). The results show that for the PBGAs with moisture content, popcorning occurs not at the peak solder-reflow temperature, but at an earlier stage.