Mitigation of corrosion challenges for barrier films at advanced nodes

Abstract

This work addresses the corrosion and galvanic corrosion challenges that can arise from the use of various novel barrier materials Ru/TiN, Co and Mn during barrier CMP in the back end of the line (BEOL) interconnects for advanced nodes.

Cobalt “Buff Step” Chemical Mechanical Planarization

“…Cobalt has been used as a liner in back end of the line applications, replacing traditional films such as TaN/Ta due to its lower resistivity, and due to the fact that copper can be directly electroplated on cobalt. 1 Additionally, applications of cobalt in other parts of the device structure, such as middle of the line (MOL) metallization, are being investigated. Since the adoption of dual-damascene structures, tungsten has been the metal of choice for plugs and local interconnects in MOL metallization.…”