Simulation of Adhesive Flow during ACF Bonding Process for Display Interconnect

Anisotropic conductive films (ACF) has been a key material employed in LCD packaging technologies. The aim is to connect the electrodes in the LCD glass to the IC driver by the trapping conducting particles at the interconnects. One of the main challenges is to control the deformation degree of conducting particles. In this paper we investigate the effect of the bump layout to reduce the squeeze film pressure. As expected, there is a strong correlation between the bump gap and the bump height on the flow rate. More importantly, the non-linear relation between the gap and the flow-rate means that the flow-rate can be increased by introducing varying the gap between the bumps for the same total number of bumps. Also the effect of adding more rows of bumps is investigated. Analytical models give an improved understanding of most of the critical parameters in the process. Based on this background, finite element modeling is used to find the effective bump geometry modification in reducing bonding force.