Copper wiring encapsulation at semi-global level to enhance wiring and dielectric reliabilities for next-generation technology nodes

The semi-global level is rather different from the intermediate level in terms of wiring scale and types of interlayer dielectrics, which has an impact on the encapsulation capability of MnO. The difference in both levels, therefore, requires major changes of the processes such as the deposition conditions of CuMn seed and capping film. We successfully enhanced wiring and dielectric reliability at the semi-global level as well as at the intermediate level in 45-nm-node technology. For electromigration and dielectric stability, MnO segregated along the outline of the Cu wiring increases activation energy and voltage acceleration factor by 54 and 47%, respectively. These increases effectively enhance the maximum current density and the expected interlayer dielectric lifetime by factors of 28 and 70, compared to those of a control sample.