Abstract
Interface adhesion energy between copper and polyimide films, which is used as flexible printed circuits, was evaluated. Contrary to the peel test commonly applied to such a case, interface crack-extension with less amount of plastic deformation was realized by a new technique. On the basis of experimental data, elastic-plastic finite element model was calculated to independently determine the amounts of plastic work and energy consumed to separate the interface during the crack extension process. Both the approaches of total energy balance and work given by nodal force and displacement at the crack tip agreed well and resulted in the same amount of the interface energy release rate.
