晶圆级芯片尺寸封装柔性焊点热循环可靠性  

Reliability of Solder Joints with the Compliant Layer in Wafer Level Chip Scale Package under the Thermal Cycle

作　　者：梁颖[1] 黄春跃[2] 熊国际 张欣[1] 李天明[3] 吴松[2] 郭广阔[2] 

机构地区：[1]成都航空职业技术学院电子工程系,成都610021 [2]桂林电子科技大学机电工程学院,广西桂林541004 [3]桂林航天工业学院汽车与动力工程系,广西桂林541004

出　　处：《半导体技术》2014年第8期621-628,共8页Semiconductor Technology

基　　金：四川省教育厅科研资助项目(13ZB0052);广西壮族自治区自然科学基金资助项目(2012GXNSFAA053234;2013GXNSFAA019322)

摘　　要：建立了晶圆级芯片尺寸封装(WLCSP)柔性无铅焊点三维有限元分析模型,基于该模型对柔性无铅焊点热循环等效应力应变进行了分析,并预测了焊点可靠性寿命。选取第一柔性层厚度、第二柔性层厚度、上焊盘直径和下焊盘直径作为关键因素,采用L16(45)正交设计了16种不同水平组合的柔性无铅焊点,获取了这些焊点的热循环等效应力数据,对等效应力数据进行了极差分析和方差分析。结果表明:在热循环加载条件下,采用柔性层结构方式能有效降低焊点内的等效应力应变;在置信度为90%的情况下,下焊盘直径和第一柔性层厚度对柔性焊点等效应力有显著影响。各因素对焊点等效应力的影响排序为下焊盘直径影响最大,其次是第一柔性层厚度,再次是第二柔性层厚度,最后是上焊盘直径。The 3D finite element analysis models of the lead-free solder joint with the equivalent compliant layer in wafer level chip scale package （WLCSP） were established. Based on the models, the equivalent stress and strain distribution under the thermal cycle on the lead-free solder joints with the compliant layer were analyzed, and the reliable fatigue life of the solder joint was also calculated. The first compliant layer thickness, second compliant layer thickness, die-side pad diameter and substrate-side pad diameter were selected as the four key configuration parameters, an L16 （45） orthogonal array with 16 different configuration parameters levels combinations for the lead-free solder joint with the compliant layer was designed. The equivalent stress data of the lead-free solder joints under the thermal cycle were obtained. The range analysis and variance analysis were equivalent made for the equivalent stress data. The results show that the structure of double compliant layers WLCSP can decrease the equivalent stress and strain in solder joints compared to the conventional WLCSP structure under the thermal cycle. With 95% confidence, the substrate-side pad diameter and first compliant layer thickness have great effect on the equivalent stress of the solder joint under the thermal cycle. The substrate-side pad diameter, first compliant layer thickness, second compliant layer thickness and die-side pad diameter affect the equivalent stress of solder joints in a descending order.

关 键 词：柔性无铅焊点 应力应变 热疲劳寿命 有限元分析 极差分析 方差分析 

分 类 号：TN305.94[电子电信—物理电子学]