Production worthy interconnect process for deep sub-half micrometer back-end-of-line technology

摘要

The present invention is directed to improving the throughput of the process for fabricating multilayer interconnects. Tungsten plugs, formed in contact/via openings etched in an interlayer dielectric, have been widely used in industry to form interconnection between different metal layers. An adhesion layer comprising a Ti/TiN stack is typically employed to support the adhesion of the tungsten plug in the contact/via openings. The present invention is directed to a process involving the formation of a Ti/TiN landing pad at the base of contact/via openings prior to the deposition of the interlayer dielectric. The process of the present invention enables the removal of the Ti under-layer and the reduction of the TiN thickness in the Ti/TiN stack. The throughput of the process for fabricating multilayer interconnects is thus greatly improved while the integrity of the devices are maintained.