Degradation of fracture and fatigue properties of MEMS structures under cyclic loading

The fracture and fatigue properties of LIGA nickel MEMS structures were evaluated by microtensile and fatigue test methods. A microtensile/fatigue device was developed and specimens with feature size ten micrometers were used. The fatigue property was derived from displacement amplitude - the number of cycles to failure curve by applying a dynamic load with a piezoelectric actuator. The tensile/fracture properties after various cyclic loading were also measured. Both fatigue and tensile test results showed a cyclic softening phenomenon.