Electrical reliability issues of integrating low-K dielectrics with Cu metallization

Electrical reliability issues of two organic aromatic low-K materials (K 2.6/spl sim/2.8) were investigated. Both materials show acceptable thermal stability and good dielectric barrier property against Cu penetration. C-V curve instability was observed under bias-temperature stress (BTS) for the first time. It can be explained by the model of stress induced dielectric polarization charges. This instability may be an issue of long term stability of circuits.