Flow Behaviour of Anisotropic Conductive Adhesive Film during COG Bonding Process in Flat Panel Display Assembly

Anisotropic conductive adhesives have emerged as an important joining technology in a number of significant application areas, such as fine pitched driver IC for flat panel display assembly and smart cards. In the past research work in this field, it has been shown that the pressure distribution and adhesive compression flow predicted using the Newtonian and non-Newtonian FV models both agree closely with those from the previously developed analytical model. This gives confidence in the FV modelling approach and therefore the results predicted more complex situations which the analytical model cannot address. These results further confirm that a more sophisticated modelling approach is required in order to allow a full understanding about the effects of the assembly process on its final properties when the adhesive flows. An analytical model has been proposed in this paper which takes into account more complex bump geometry and can be used to predict the velocity and pressure drop distribution through the entire chip during the COG bonding process. The analytical solution is followed by the finite element modelling, which agrees well with the analytically predicted solution