Analytical approach to evaluate shear stress in flip chip interconnection using NCA/ACF

The flip chip technique using non-conductive adhesive (NCA) or anisotropic conductive film (ACF) has become a key technology for fine-pitch interconnection such as display packaging for compact electronic products. This film type electronic package, flip chip assembly on organic substrate such as FR-4 printed circuit board (PCB), has advantages such as low cost, reliable electronic performance, easier assembly process, and low temperature process. To account for the deterioration in electrical performance during high temperature operation, both analytical and experimental investigations were performed in this study. Interfacial shear stress along the adhesive layer was examined by applying existing analytical solutions for film structures. Analytical approaches were, then, compared with a numerical FEA solution and verified by experimental data obtained by a Moire interferometry experiment.