Ultrathin conformal multilayer SiNO dielectric cap for capacitance reduction in Cu/low k interconnects

Multi-layer SiNO barrier film with high breakdown and low leakage is developed for Cu low k interconnects and is compared with the SiCN and SiN barrier films used at previous technology nodes. Combining SiCN with multi-layer SiNO barrier film provides robust Cu and O barrier properties at film thickness of ~10-14 nm. SiNO layers in the bi-layer film help lower the dielectric constant and hence provide capacitance benefit in the integrated structures. The high breakdown SiNO layers provide benefit in the via chamfer region and improves inter-level time dependent dielectric breakdown (TDDB). Overall, the SiCN/SiNO bilayer dielectric film shows robust device reliability as compared to the state of the art barrier films.