Recent study on the related problems in evaluation of mechanical properties for MEMS materials

In order to obtain reliable evaluation result by nanoindentation, the related problems during measurement of the hardness and elastic modulus are investigated. Two quantitative approaches, i.e. calculating actual contact area and correcting contact depth errors, are proposed to deal with the significant pile-up errors for indentation on those ductile soft materials, especially thin soft metal films on hard substrates. The various influence factors during indentation are analyzed, and a new method for uncertainty estimation in hardness and elastic modulus is provided based on the random-fuzzy variables. Through the illustration of Au/glass-ceramic and Al/7059 glass, both the quantitative approaches are suitable for the elastically matching film-substrate systems. The measurement uncertainties in hardness and elastic modulus of Si(100) are effectively estimated, and all possible influencing effects on uncertainty can be involved.