Lattice-Boltzmann analysis of pressurized underfill process for I-type dispensing method

This paper studies the three-dimensional simulation of pressurized underfill process for I-type dispensing method on a 10 by 10, middle empty ball-grid-array (BGA) using lattice-Boltzmann method. Underfill encapsulations plays an important role in increasing the reliability of a flip chip package. Pressurized underfill process is introduced to overcome the drawbacks of the usual capillary underfill process which include extended filling time, incomplete filling and the high chances of void formation. Four different pressure values are used as the input pressure in the lattice-Boltzmann simulation of the pressurized underfill process. It was shown that the high pressure region concentrates at the inlet region, while the peak pressure in the flow domain is around four times the initial input pressure.