Study on flow visualization of flip chip encapsulation process for numerical simulation

Flip chip package is the most important technology in IC package necessary for scale, velocity and cost by the development of semiconductor technology and the innovation of computer product. It has the advantages of low cost, low interface and small volume in IC package. This paper emphasizes the analysis for underfill encapsulation between the solder ball and chip. The finite element simulation in a three-dimensional inertia-free, incompressible flow is presented. A control volume scheme with a fixed finite element mesh is employed to predict fluid front advancement. The epoxy is used for the underfill material. The injection situation is used for central point, one line, L line and U line injection. The underfill process is used for different parameters (mold temperature, melt temperature, injection pressure, injection time and injection situation). The results show that the injection situation is the most important factor for processing parameters. The result indicates that the L line injection is the best injection situation for underfill encapsulation of flip chip.