Flow characterization and thermo-mechanical response of anisotropic conductive films

The paper reports about investigations on the chip on glass (COG) bonding p rocess using anisotropic conductive films (ACF), Experimental methods as we ll as theoretical analyses, by both analytical and numerical means, are app lied. The assumptions concerning the thermo-mechanical and Rheological prop erties of the polymer materials involved in the bonding process are shortly characterized in dependence on temperature. The transient development of t he temperature field during the bonding process is studied by finite elemen t (FE) analysis in dependence on the upper and lower chuck temperatures. An alytical techniques of fluid mechanics are used to predict the how of the c onductive particles during bonding, treated as dimensionless points embedde d in a viscous matrix. This analytical description allows to estimate the n umber of conducting particles on a bump of a chip after bonding, Furthermor e, numerical calculations are applied to characterize the influence of visc osity gradients on the particle how. Finally, nonlinear finite element simu lations are used to investigate the stress development and stress relaxatio n process within the ACF joints.