Effects of passivation layer on stress relaxation in Cu line structures

In this study, we investigate the effect of passivation layer on mass transport by measuring stress relaxation in Cu damascene line structures. SiC and SiN/sub x/ passivation layers are investigated and compared with no passivation to examine the bonding effect on mass transport. The observed stress relaxation behavior is analyzed by a kinetic model considering the contribution to mass transport via various diffusion paths including the passivation interface. Results of this study show a significant effect due to the passivation layer that can be attributed to the interfacial chemistry.