Ultra fine pitch flat panel display packaging using 3 μm conductive particles

In this research, dependency of the contact resistance on the hardness of the gold bump and process parameters such as the contact area and the load pressure of the extra fine pitch chip-on-glass (COG) flat panel display (FPD) packaging is investigated. The FJ2530 anisotropic conductive film (ACF) by Sony Inc. containing the currently smallest 3 μm conductive particles is implemented to conduct the experiments. Feasibility of the 3 μm ACF in ultra-fine pitch COG applications is further examined. From the experimental results, we found that no special process is required to obtain a satisfied contact resistance for the ultra fine pitch packaging based on the 3 μm conductive particles. It can be concluded that the combination of the 3 μm conductive particles and the IC gold bumps with hardness 70 Hv can lead to a miniaturized device with less cost. For mass production, test sample with pitch space being larger than 10 μm is suggested to retain a better reliability.