Evaluation of interface adhesion strength in Cu/(Ta-x% N, Ta/TaN)/SiO ₂/Si by nanoscratch test

The adhesion strength of Cu/(Ta-x% N, Ta/TaN)/SiO₂/Si was investigated and the feasibility of the nanoscratch technique was evaluated. Because of the grain orientation dependence of critical load owing to elastic/plastic anisotropy, the interface adhesion measured in the mix-textured films of (111) and (100) showed a wide-range data spread to higher adhesion strength compared with the highly (111) textured films. The adhesive energy derived from the measured critical load by considering the residual stress and the effect of grain orientation by the aid of finite element method calculation showed a reasonable agreement with theoretical work of adhesion. It was revealed that the adhesion strength of Cu/Ta-x% N decreases with increasing nitrogen concentration. This tendency can be associated with increasing number of weak Cu-N bonding along the Cu/barrier interface.