Measurement for mechanical behavior and fatigue property of Cu films by nanoscale dynamic load method.

Mechanical behavior and fatigue properties greatly influence the reliability and life of film materials. Quantitative testing of film fatigue property under dynamic load is realized on the basis of nanometers thick Cu films deposited on monocrystalline silicon substrates by magnetron sputtering system. Microstructure and surface pattern of copper films are characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Film hardness and modulus are measured by quasi-static test and continuous measurements (CMX) systems of nanomechanical testing instrument. Fatigue damage behaviors are investigated by nanoscale dynamic mechanical analysis (nanoDMA) technique. The results indicate that Cu films prepared by magnetron sputtering system present (1 1 1) preferred orientation and contain a large number of nanoscale grains with uniform texture and low roughness. As is affected by substrate and small scale effect, CMX method is more suitable than quasi-static method for the measurement of micro-mechanical properties of ultra-thin films. Fatigue dominantly happens in thinner films. Factors, like thickness, inner stress, modulus and hardness, can influence fatigue life of nanoscale Cu films. [ABSTRACT FROM AUTHOR]