Aging studies of PBGA solder joints reflowed at different conveyor speeds

PBGA packages are more susceptible to solder joint fatigue problem due to the significant mismatches of the coefficient of thermal expansion (CTE) between bismaleimide triazine substrate (/spl sim/15 ppm//spl deg/C) and silicon die (/spl sim/2.5 ppm//spl deg/C). In this paper, the shear cycle fatigue properties of PBGA (Topline DC169) solder joints reflowed with different profiles, and aged at 125/spl deg/C for 4, 9, 16, 25, and 36 days are studied. The profiles are devised to have the same "heating factor", which is defined as the integral of the measured temperature above the liquidus (183/spl deg/C) with respect to dwell time in the reflow profile, but to have different conveyor speeds. The effects of conveyor speed on the solder joint (non-aged and aged) fatigue lifetimes are investigated.