Influence of the Bonding Force, Anisotropic Conductive Film (ACF) and Reflow Process on the Flip Chip Assembly

Abstract

Flip chip assembly on FR4 board using anisotropic conductive films (ACFs) is gained more attention because of its many advantages. But to obtain more reliable flip chip assembly, it is necessary to control the parameters involved in the process. In this work, the effect of bonding force of ACF, as well as the kind of ACF and the parameters evolved in the reflow process on the ACF flip chip joints were investigate. It was observed a formation of the high conduction gap for ACF joints bonded with lower bonding forces after reflow. This high conduction gap can result in electrical disconnection in the worst case.