Anisotropic conductive film (ACF) interconnection for display packaging applications

A systematic experiment on ACF interconnection has been carried out to understand and design better quality ACF materials for display packaging application. The electrical and mechanical properties of the ACFs were studied as a function of the curing kinetics of an adhesive epoxy resin. To observe the change of the electrical properties of the ACFs resulted from the curing of an adhesive epoxy resin during the bonding, an in-situ method measuring the contact resistance of the ACF was developed. The 90° peel test was conducted to examine the mechanical properties of the ACF. The bounce up in the contact resistance of the ACF was detected just after the finish of the bonding. It was shown that the amount of the bounce up depends on the curing kinetics of an adhesive epoxy resin and mechanical properties of the fine conductive particles. As the degree of the curing of an adhesive epoxy resin and the ability of the elastic deformation of the fine conductive particle decreases, the amount of the bounce up increases. Electrical conduction between the particles and the conductive surfaces are constructed by the deformation of conductive particles with applied pressure. Therefore the electrical resistance of ACF depends on the external pressure, number, size, mechanical and electrical properties of particles. In general, as bonding pressure increases, a sharp decrease of contact resistance followed by a constant value is observed after reaching the critical bonding pressure. As the conductive particle content increases, the connection resistance decreases and becomes constant