Suppression of Resistance Increase in Annealed Al/W Interconnects by Capacitively Coupled Plasma Nitridation on W Surface

Autor: Sekiguchi, Mitsuru, Fujii, Toyokazu, Michinari Yamanaka, Michinari Yamanaka
Zdroj: Japanese Journal of Applied Physics; February 1996, Vol. 35 Issue: 2 p1111-1111, 1p
Abstrakt: The suppression of the resistance increase in annealed Al/chemical vapor deposition (CVD)-W interconnects has been achieved by exposing the W surface to N2plasma before Al deposition. The N2plasma was generated in a capacitively coupled parallel-plate reactor. This process forms a thin WNxlayer at the interface between the Al and the W layer. The WNxlayer prevents Al-W alloy formation during annealing at 450°C. With this N2plasma treatment, the resistance increase after annealing at 450°C is suppressed to only 10% compared to 140-180% in samples without the N2plasma treatment. The N/W ratio and the thickness of the WNxlayer are about 1.1 and 4 nm, respectively. The WNxlayer formed in our experiment is found to be thicker and have a higher N concentration than the WNxlayer formed by electron cyclotron resonance (ECR) plasma nitridation. This is probably due to the large self-bias voltage of the N2plasma generated in a capacitively coupled parallel-plate reactor.
Databáze: Supplemental Index