Abstract: Tensile fatigue properties of notched and smooth specimens for free-standing electroplated copper films with 11.5 μm thickness are studied. The tests are completed by using MMT-11N micro mechanical fatigue testing system. The specimens are fabricated with LIGA-like technology. The tests are carried out at room temperature under tension-tension cyclic loading with 20 Hz load frequency. S-N curve, cyclic –N curve and –N curve are obtained. Based on the modified local stress-strain approach, fatigue lives of notched specimens are predicted. The results agree well with the experimental fatigue lives. It proves that the hysteresis loop on half of the life cycle can be still used as stable hysteresis loop in micro mechanical fatigue, and the local stress-strain approach can be applied in life prediction of MEMS fatigue, thus the traditional fatigue research methods are also suitable for description of MEMS fatigue in a certain extent.

Key words: Copper film, Electroplated, Fatigue, Life prediction