Abas Aizat, Gan Z L, Ishak M H H, Abdullah M Z, Khor Soon Fuat
School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia.
School of Aerospace Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia.
PLoS One. 2016 Jul 25;11(7):e0159357. doi: 10.1371/journal.pone.0159357. eCollection 2016.
This paper studies the three dimensional (3D) simulation of fluid flows through the ball grid array (BGA) to replicate the real underfill encapsulation process. The effect of different solder bump arrangements of BGA on the flow front, pressure and velocity of the fluid is investigated. The flow front, pressure and velocity for different time intervals are determined and analyzed for potential problems relating to solder bump damage. The simulation results from Lattice Boltzmann Method (LBM) code will be validated with experimental findings as well as the conventional Finite Volume Method (FVM) code to ensure highly accurate simulation setup. Based on the findings, good agreement can be seen between LBM and FVM simulations as well as the experimental observations. It was shown that only LBM is capable of capturing the micro-voids formation. This study also shows an increasing trend in fluid filling time for BGA with perimeter, middle empty and full orientations. The perimeter orientation has a higher pressure fluid at the middle region of BGA surface compared to middle empty and full orientation. This research would shed new light for a highly accurate simulation of encapsulation process using LBM and help to further increase the reliability of the package produced.
本文研究了流体通过球栅阵列（BGA）的三维（3D）模拟，以再现实际的底部填充封装过程。研究了BGA不同焊球排列对流体流动前沿、压力和速度的影响。确定并分析了不同时间间隔下的流动前沿、压力和速度，以找出与焊球损坏相关的潜在问题。将用实验结果以及传统的有限体积法（FVM）代码对格子玻尔兹曼方法（LBM）代码的模拟结果进行验证，以确保模拟设置的高度准确性。基于这些发现，可以看到LBM和FVM模拟以及实验观察结果之间有很好的一致性。结果表明，只有LBM能够捕捉微孔隙的形成。本研究还表明，BGA在周边、中间为空和满填充方向的流体填充时间呈增加趋势。与中间为空和满填充方向相比，周边方向在BGA表面中间区域具有更高的压力流体。这项研究将为使用LBM进行封装过程的高精度模拟提供新的思路，并有助于进一步提高所生产封装的可靠性。
