基于表面能理论的倒装芯片封装下填充流动研究

为了预测倒装芯片封装中的下填充过程,通常要首先通过繁复的方法来求解平均毛细压.为了避免此问题,从能量的角度分析了倒装芯片封装工艺中的下填充流动过程.认为下填充是较低表面能的界面代替较高表面能的界面的过程,所释放的表面能用于形成流体流动的动能和克服阻力的能量损耗,期间能量守恒.在此分析的基础上建立了下填充流动的新模型.建立了可视化的下填充流动实验装置,并用下填充实验验证了所建立新模型的准确性.该模型避免了计算平均毛细压的复杂过程,并可方便地扩展到焊球排布形式不同的倒装芯片.

Research on Underfill Flow in Flip-Chip Packaging Based on Surface Energy Theory

In order to predict the underfill process in flip-chip packaging,the average capillary pressure is usually first solved through complicated methods.The underfill flow in the flip-chip packaging process was analyzed from the energy perspective to avoid this problem.Underfilling was considered as the process that the interface with lower surface energy took the place of the interface with higher surface energy.The surface energy released in this process could be used to produce the kinetic energy of the fluid flow and the energy loss to overcome the resistance.In the process,the energy was conserved.Based on this analysis,a new model of underfill flow was established.A visualization device was set up for the underfill flow experiment and the accuracy of the new model was verified by the underfill flow experiment.This model avoids the complex process of calculating the average capillary pressure and can be easily extended to the flip-chip with different solder bump arrangement.