Cyclic Magnetic Actuation for Potential Characterization of Interfacial Fatigue Fracture

An innovative fixtureless test technique to study interfacial fatigue fracture in thin film stacks is proposed and implemented. Cyclic noncontact magnetic actuation is employed to supply the fatigue crack driving force along the interface between a released metal thin film cantilever and the supporting substrate. In-situ crack growth measurements with nanometer resolution are possible through electrical resistance monitoring of nanoscale metal traces that are located along the edge of the delaminating interface. Ti/Au nano metal traces are fabricated using electron-beam lithography and characterized to show stable electrical behavior. The fatigue test results were then used to assess the reliability of micro contact springs under fatigue loading for wafer probing applications.