This study considers the influence of solder joint voiding and seating plane stability on the lead standoffs of surface mount technology (SMT) solder joints. A model is presented for approximating the reaction force generated by a gas-filled void in molten solder which is compressed under an SMT lead. Seating plane stability is defined with a simple model. The lead standoffs of a component with an unstable seating plane are sensitive to small forces. For some SMT components, the reaction force generated by compressed voids in molten solder can tilt or rock a component, resulting in lead standoffs much greater than the measured lead coplanarity.

This content is only available via PDF.
You do not currently have access to this content.