PBGA器件固化残余应力的有限元分析

采用有限元分析软件模拟研究了PBGA器件在先固化再进行温度加载和直接从温度循环开始加载两种情况下,固化过程对 PBGA 器件的影响,发现固化过程不仅改变了器件中芯片的应力分布,而且劣化了 DA(环氧树脂)材料与芯片接触面的应力值,也同时使得 BT 材料基底中的应力分布产生较大的改变。并且对 DA 材料选用几种不同的固化时间,发现固化时间的不同对器件封装残余应力的大小和最大应力位置有重要的影响,这为预测芯片的垂直开裂的位置提供了很好的依据。

Finite Element Simulation Analysis on Cure-residual Stress in PBGA Device

The cure behaviour of the thermosetting polymers may introduce additional stresses, because every material has different coefficient of thermal expansion. Over the past decades, an increasing interest was found in numerical techniques for predicting the mechanical stresses in thermosetting matertals during and after cure. In order to know the effect of cure-residual stress on the device, Finite element method simulaion to plastic ball grid array device according two temperature loading curves was presented. Two curves: one is thermal cycles curve, the other is curing and thermal curve. Additional, several different curing times are selected to the Die attach, show that the magnitude of the cure-residual stress and the situation of the maximal stress have direct relations of curing time in PBGA.