| SiP has been widely used in all kinds of electronic equipment for its features of multifunction and high integration,but its reliability cannot be ignored.Aiming at the thermal vibration reliability problem of SiP,the failure point and fatigue life prediction of SiP chip under normal operation,the failure point and fatigue life prediction under random vibration,and the reliability analysis under the combined action of thermal vibration load were studied.The reliability of the welding column under random vibration load is analyzed and the structure optimization is carried out by the response surface model combined with particle swarm optimization algorithm.The failure point of the bonding line structure in the microcomponent was studied under thermal cycling load and optimized by Taguchi experiment.Research shows that:In actual operation of SiP,the thermal stress of structure is mainly concentrated in the welding column and the corner of micro-components.The dangerous point of the structure is found at the lower right corner of the welding column array under the thermal cycle load and the fatigue life is calculated.The dangerous point of the structure is located at the upper right corner of the welding column array under random vibration load and the fatigue life is calculated.The superimposed damage under thermal vibration load is analyzed,in which the damage under random vibration load is dominant.The results of random vibration analysis at different temperatures show that the predicted fatigue life of welded column array decreases gradually with the increase of temperature.The results show that increasing the diameter of welded column and the thickness of PCB can reduce the maximum equivalent stress and increase the fatigue life under random vibration load.Response surface model analysis shows that the diameter of welded column and the thickness of PCB have significant effects on the maximum equivalent stress and strain of the chip structure.The interaction between the diameter of welded column and the height of welded column and the thickness of welded column and PCB board has significant effects on the maximum equivalent stress and strain.Particle swarm optimization algorithm was used to optimize the welded column structure and simulation was carried out.Maximum equivalent force reduced by 6.45% and strain reduced by 5.13%.The failure points of the bonding wire structure in the SiP component are concentrated at the bottom of the solder joint and the neck of the bonding wire.The results show that reducing the wire diameter,the horizontal between the first and second solder joints,and increasing the arch height of the wire and the vertical distance between the first and second solder joints can help to improve the reliability of the wire structure and prolong the fatigue life Based on Taguchi’s experiment,it is found that the horizontal spacing of solder joints has the greatest influence on the reliability of bonding wire.The maximum equivalent force was reduced by25.4% after optimization. |
