Reliability study and parameter optimization of BGA laminated solder joints under thermal cycling conditions
It is of great significance to construct optimal structural parameters for laminated solder joints and improve their reliability under thermal cycling conditions.A finite element model was established to analyze the stress and strain of the laminated solder joints under thermal cycling conditions.Using Taguchi orthogonal method and response surface methodology,the maximum equivalent plastic strain of the critical solder joints was optimized by setting variables such as height,diameter,spacing,and array of the solder joints for the experimental design.The results show that the solder joint array has the greatest impact on optimization objective.The optimized structural parameters for the BGA laminated solder joints are given as follows.For Taguchi orthogonal method,the optimized single joint height,spacing,diameter are 0.38 mm,0.55 mm,and 0.44 mm respectively with array of 8x8.For response surface methodology,the optimized single joint height,spacing and diameter are 0.387 mm,0.573 mm,0.446 mm respectively with array of 8×8.The lifetime was predicted before and after optimization.The lifetime of the optimized stacked solder joints is approximately 3.75 times that of the unoptimized ones.
finite element methodexperimental designthermal cyclingBGA double-stacked solder jointsparameter optimization