Highly Reliable Flip-Chip-on-Flex Package Using Multilayered Anisotropic Conductive Film

Anisotropic conductive lm (ACF) has been used as interconnect material for at-panel display module packages, such as liquid crystal displays (LCDs) in the technologies of tape automated bonding (TAB), chip-on-glass (COG), chip-on-lm (COF), and chip-on-board (COB). Among them, COF is a relatively new technology after TAB and COG bonding, and its requirement for ACF becomes more stringent because of the need of high adhesion and ne-pitch interconnec-tion. To meet these demands, strong interfacial adhesion between the ACF, sub-strate, and chip is a major issue. We have developed a multilayered ACF that has functional layers on both sides of a conventional ACF layer to improve the wetting properties of the resin on two-layer ex for better interface adhesion and to control the ow of conductive particles during thermocompression bond-ing and the resulting reliability of the interconnection using ACF. To investi-gate the enhancement of electrical properties and reliability of multilayered ACF in COF assemblies, we evaluated the performance in contact resistance and adhesion strength of a multilayered ACF and single-layered ACF unde