AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP11
Modeling and Experimental Characterization of a Ti/Nitrogen/Ar Ionized Physical Vapor Deposition Tool

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: K. Tao, Northeastern University
Authors: K. Tao, Northeastern University
D. Mao, Northeastern University
J. Hopwood, Northeastern University
Correspondent: Click to Email
The deposition of adhesion layers, diffusion barriers, and seed layers into high-aspect-ratio features is a critical technology for next-generation integrated circuit interconnects. One method of directionally-depositing materials is ionized physical vapor deposition (IPVD). Sputtered atoms are ionized in IPVD by a high-density plasma and, subsequently, collimated toward the wafer by the plasma sheath potential. Although considerable work has been reported on the deposition of metal films using argon as the working gas, very little is known about reactive sputter deposition using IPVD. The formation of high quality metal-nitrides that exhibit high conformality is possible using a working gas of nitrogen and Ar. The Ti-Ar-N@sub 2@ plasma, for example, is used for the deposition of TiN. Reactive IPVD is being studied both experimentally and through analytical plasma modeling. The gas-phase densities of ionized, excited, and dissociated species of Ti, Ar, and nitrogen are predicted and compared with experimental measurements that include mass spectrometry, optical emission spectroscopy, and Langmuir probes. The dissociation of nitrogen is used to benchmark the model. Both the model and measurement show that the dissociation fraction lies between 5% and 20% and decreases with increasing plasma pressure. The effect of nitrogen on the degree of ionization of sputtered titanium, and therefore the bottom-coverage of high aspect ratio features, will also be discussed.