Solder stability for Pb-free HBGA assembly with oxygenous reflow

In ball-grid-array (BGA) package technology, the oxygen concentration in flow process predominantly influences the quality of solder conjunction such as oxidation causing aged effect and quality of inter-metallic compound. In addition, the flux as solder assistance is also a key factor determining the solder adhesion ability between carrier HBGA substrate and solder ball. Using the temperature cycling test, shear test and drop test to distinguish the adhesion ability for lead-free solder balls on HBGA substrate assisted with several fluxes, the optimal process recipe was achieved. The soldering performance was impressive.