PBGA组件的动态特性仿真与实验研究

Dynamic simulation and experiments of a PBGA assembly

为了得到振动条件下塑料球栅阵列封装(PBGA)芯片在PCB板上焊接位置以及PCB加固方式对动态特性的影响,设计制作了一块包含不同结构和材料参数的PBGA组件样品,首先采用ANSYS软件建立PCB组件的有限元模型,在建模过程中采用了简化PBGA结构和减少焊点数量的方法减小计算量,通过模拟计算得到了该组件样品在不同加固条件下的一阶频率与模态变形。然后结合模态实验的方法进行了不同边界条件下的动态测试分析。运用模态分析方法获得了各加固条件下的模态参数。最后以边四点加固方式为例,比较了仿真与试验的相互匹配性与差异性。分析结果表明:芯片分布在四点固定板上、增加约束数目、靠近约束点布片可以有效改善动态特性。

In order to obtain influence of chip position and fix methods on dynamic property of a plastic ball grid array(PBGA) under vibration environment,a group of specified PBGA assembly chips with different structure and material parameters were designed and produced.The software ANSYS was used to build up their finite element model.In modeling process,simplified PBGA structure accompaning with less numbers of solder joints were utilized to decrease calculations.From simulation,the 1st modal frequency and modal deformation could be achieved under different fixed ways.Experimental modal analysis method was combined with the dynamic test under different consolidations.Finally,a side four-point fixed way was taken as an example to compare the correspondence and difference between the simulation and test.Results showed that ways making chips on a four-point board,increase in constraints and making chips near constraint could improve the dynamic property effectively.