BGA底部填充胶核心性能评估方法探讨

Discussion on key properties evaluation methods of BGA underfill

在BGA焊接组装后的各种不同的可靠性模拟测试中,特别是跌落和高低温循环,底部填充胶固化后的玻璃化转变温度(T_(g))、线性膨胀系数(CTE)和弹性模量((E′)等性能的匹配性,对于其工作的可靠性显得尤其重要。选取底部填充胶UB-38XX,TMA建议使用5 K/min以下的升温速率、5 mm以下样条厚度进行CTE和T_(g)测试,DMA推荐3点弯曲模式的弹性模量测量,使用1 K/min的升温速率,1 mm的样条厚度进行弹性模量测试。

In the various reliability simulation tests of BGA after welding and assembly,especially drop and high and low temperature cycle,the matching of glass transition temperature(T_(g)),coefficient of linear expansion(CTE)and elastic modulus(E′)after underfill adhesive curing is particularly important for its working reliability.In this paper,underfill UB-38XX is selected.It is recommended to use TMA with the heating rate below 5 K/min and the spline thickness below 1 mm for CTE and T_(g)test.For DMA,it is recommended to three-point bending mode for elastic modulus measurement,with 1 K/min heating rate and 1 mm spline thickness for elastic modulus test.