Application of response surface methods in Lead-free solder joints of plastic ball grid array thermal fatigue life prediction

Aiming at solder ball diameter, solder ball height, solder ball distance and welding plate thickness these four factors of Lead-free solder ball in plastic micro ball grid array devices, this paper uses the analysis method of the combination of the finite element analogy and response method, to analysis thermal fatigue life of lead-free solder ball in plastic micro ball grid array device. Based on 29 experiment combinations under hot cyclic loading the mechanical simulation analysis, surface response method is used to get the stress-strain ring change range of maximum shear stress solder about Prediction model. The results show that, when the solder ball diameter of 0.7 mm, solder ball height of 0.4 mm, solder ball distance of 1.27 mm, welding plate thickness of 0.03 mm, the Numerical Δr is minimum, and the corresponding solder life is the largest. Meanwhile the influencing degree of 4 factors about statistics Δr, is Solder ball diameter>;solder ball distance >; solder ball height>; welding plate thickness. Namely solder ball diameter of lead-free solder ball has biggest influence of thermal fatigue life.