A model for patterned interfaces debonding - Application to adhesion tests

Patterned interfaces are widely used in the industries of microelectronics and micro-electromechanical systems and are of general interest for obtaining specific interface properties by playing on geometry as an additional parameter influencing physical processes (interface engineering). In this paper, a novel analytical model is proposed to characterize the debonding of patterned interfaces. This model is accounting for both stretching and rotation of the finite width bond lines composing a patterning between two plain substrates. The model highlights how the choice of pattern periodicity and line width allows for controlling the interface mechanical behavior during debonding: presence of stable and unstable crack growth regimes. It is shown that models considering a continuum interface are to be used with care when dealing with patterned interfaces. The model proposed here, used in conjunction with an experimental procedure providing the sample bending profile during a wedge test (or a DCB test) should provide valuable guidance for determining the interface fracture energy Gc (mode I) for a patterned interface.