Advanced i-PVD barrier metal deposition technology for 90 nm Cu interconnects

An advanced i-PVD(ionized physical vapor deposition) barrier metal deposition technology has been developed for 90 nm Cu interconnects. The feature of this technology is to re-sputter the thick barrier metal at the contact/trench bottom, which was deposited by i-PVD, and attach the re-sputtered barrier metal to the sidewall. By using this technology, it is possible to obtain relatively thin bottom and thick sidewall coverage and thus a more conformal deposition. This technology is shown to be very effective in both lowering via resistance and improving reliabilities of 90 nm Cu interconnects embedded in SiOC-type low-k(k=2.9) inter-metal dielectric.