Numerical Modeling for the Underfill Flow in Flip-Chip Packaging

Three-dimensional simulation of underfill process in flip-chip encapsulation

“…For verification purpose, the following case studies were examined. In each case, besides comparisons with the experimental results, we also present numerical results predicted by the two popular types of capillary-driven models, i.e., the surface force driven model as used in [6] and the volume force model (the CSF driven model with adhesive effect by modifying the normal vectors of the nodes in contact with the wall) as used in [11], and the simulation results of the underfill encapsulation module in the commercial CAE software Autodesk Moldflow Insight 2010 for comparison.…”

“…In the simulation, the pseudo-concentration approach was used to track advancement of the melt-front. Wan et al [6] presented a twodimensional flow simulation approach for the underfill process. In the approach, the power-law constitutive equation was used and the time-dependent velocity boundary condition was applied.…”

“…Owing to the limit of computational methods (algorithms) and capabilities (hardware and software), two-dimensional simulation approaches were developed earlier in the underfill simulation field, such as [3][4][5][6]10]. However, those approaches introduce too much simplification and cannot model the gapwise behavior, so the fluid flow in a thickness-change region and the fountain flow at the melt-front cannot be captured.…”

“…The volume force was then included in the momentum equation as an external force term. However, in the most studies [3][4][5][6][8][9][10]15,16], the wall adhesive effect (including the surface of the substrate, the die and the bumps) was neglected. Only a few studies involved the effect in the capillary action by simply-modifying the normal vectors of the nodes in contact with the wall [11,13].…”

Micro-PIV measurements of capillary underfill flows and effect of bump pitch on filling process

“…Wan et al (2009) also developed a numerical simulation method to predict the motion of flow front for non-Newtonian fluid. Nguyen et al (1999) tried to measure the flow front of capillary underfill using quartz dies.…”