Estimating lifetime of soldered joints of QFP leads

摘要

In this paper, the fundamental failure modes of the solder joints, were investigated in terms of shear, peel, and tensile and the lifetime of stressed solder joints of QFPs, which are assembled on a circuit pack mounted in the equipment frames,have been estimated, through the following experiments:(1)Using two metal plates soldered, the creep of stress in the soldered joints was determined with load applied in shear, peel and tensile load modes.(2) Reliability evaluation of soldered joints of 0.5-mm-pitched, 208-pin molded QFP mounted board displaced by three-point bending(Fig. 1), at 100°C and the creep simulationThe solder joint failure mode, peel, and the creep simulation results in terms of peel can coincide with the reliability evaluation. This revealed that the solder joint reliability can be estimated by the creep simulation, a stress of the inflection point at which stresses begin to saturate to a steady state.