Study on Linear and Nonlinear Coupling Damage Model of BGA Solder Joint

摘要

Due to the complex and changeable environment in space,the ball grid array(BGA)has become one of the most important form of the electronic package in aerospace industry.As the main factors which affect the reliability of electronic products,temperature and vibration will lead to creep and fatigue respectively.Based on the damage mechanism,taking SnAgCu solder joints as the research object,the relationship between the resistance and the damage index are established by using the micro-conductive model of resistance.The mathematical model between stress cycle and damage value is established by damage mechanics.Then,the linear and nonlinear interaction models are established to simulate the initial and mature damage of solder joints respectively based on the principle of area interference.Finally,Monte Carlo method is used to simulate the growth of the crack,concluding that it's suitable for the linear model when the damage index is less than 0.155 and the nonlinear model is suitable when the damage index is more than 0.155.