Experimental analysis and finite element modelling of nano-scratch test applied on 40–120 nm SiCN thin films deposited on Cu/Si substrate

In this work, the nano-scratch test is used to characterize the interfacial adhesion of amorphous SiCN thin films deposited by plasma enhanced chemical vapour deposition on Cu/Si substrates. The experimental results show that the critical load Fc is directly related to the rupture of the SiCN/Cu interface. A strong linear dependence of Fc to the SiCN thickness independently to the adhesion is also put in evidence. A three-dimensional finite element model of the test is then built. The results show a clear relation between the stresses into the coating and the cracking and buckling of the film observed experimentally. We then discuss how the interfacial tensile stresses can explain the increase of Fc with the film thickness.