【摘要】 利用有限元软件在再流焊温度下,分别对PBGA器件统一的宏细观模型进行了模拟分析,就内部焊球来说,发现应力变化最大的是边界焊球,失效最容易从这里产生;并且发现再流焊温度加载过程中的温度变化速率与焊点内的应力变化有直接的关系,当把冷却区的温度变化速率从3减小到1. 5时,可以从焊点的不同载荷步应力云图看出,应力突变明显降低,这对提高器件可靠性有重要意义。更多还原

【Abstract】 The reliability of a solder joint is vital to SMT product.One of the key factors affecting the reliability of reflow weld is the joints microstructure.Take PBGA solder joint as an example,simulation and analysis of PBGA solder joint based on macroscopic and microcosmic models are carried out,The results show that marginal solder joint experienced the most obvious stress diversification and will be disabled easily.Furthermore, stress nephograms according to each loading pace show that solder joints stress have direct relations to velocity of temperature loading.Stress saltation of solder joint decreased remarkably as velocity of temperature loading changed from 3 to 1.5.更多还原