Comparison between nanoindentation and scratch test hardness (scratch hardness) values of copper thin films on oxidised silicon substrates

In this paper we measured for the first time the scratch hardness of copper thin films and compared this with hardness measured from nanoindentation. Copper films with thicknesses in the range 100 nm to 500 nm were deposited by rf magnetron sputtering on silicon substrates. Scratch hardness was determined by CSM™ scratch tester using scratch widths at low loads. The measured hardness values were compared with conventional nanoindentation hardness measurement by CSM™ nanohardness tester. At these low indentation depths there is a good correlation between the scratch hardness and the nanoindentation hardness, with an increase in hardness as the film thickness decreases.