The Impact of Film Deposition Temperature and Bottom Liner on the Hardness and Grain Size of Al Films Investigated Using Nanoindentation and SEM Techniques

Materials characterization at micro- and nano- scale is important for developing robust processes in wafer fabrication. In this paper, the techniques of nanoindentation and SEM imaging are employed to study the material hardness and grain size of Al films grown under different conditions. The methodology developed by Oliver and Phar is used for Al hardness measurements while ASTM International Standard E112-12 was followed in estimating the Al grain size. It will be shown that deposition temperature of Al thin film is the bigger factor in influencing the grain size of the resulting Al film as compared to changes made to its underlying bottom liner (TiN). However, in terms of film hardness, the elimination of the bottom liner exerts a greater influence as compared to deposition temperature.