Evaluation of the crystallinity of grain boundaries of electronic copper thin films for highly reliable interconnections

The change of the crystallinity of grain boundaries of the electroplated copper thin films used for the various interconnections in electronic products was evaluated quantitatively by applying an electron back-scattering diffraction analysis. It was found that the crystallinity of the electroplated films varied drastically depending on the electroplating conditions such as the composition of solute, temperature of the plating, the current density during electroplating, the surface material on the substrate, and so on. It also changed after the annealing at temperatures higher than 200°C. The change of the crystallinity of the films caused the drastic variation of both the electrical and mechanical reliability of the films.