Properties of interfaces in Cu/Ti1−xAlxN/〈Si〉 multilayers

Ti1−xAlxN films have been grown onto Si(1 0 0) substrate by d.c. reactive magnetron sputtering as a diffusion barrier between Cu and Si. The residual stresses of Ti1−xAlxN films depended on the microstructure and composition. Higher residual stresses were obtained for Ti1−xAlxN films deposited with higher bias voltage. The minimum residual stress was 11.4 MPa, found in Ti1−xAlxN films deposited with a nitrogen flow rate of 8 ml/min and a bias voltage of −50 V. Residual stresses of Cu films decreased with the increase of surface roughness of the Ti1−xAlxN films. The good adhesion of Ti1−xAlxN films on Si substrate was due to the chemical reactions, however, the bad adhesion of Cu films on Ti1−xAlxN films was attributed to the large residual tensile stresses in Cu film.