AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP15
Ionization Processes of Metal Atoms in High-Pressure dc Magnetron Sputtering Discharges

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: N. Nafarizal, Nagoya University, Japan
Authors: N. Nafarizal, Nagoya University, Japan
K. Shibagaki, Suzuka National College of Technology, Japan
N. Takada, Nagoya University, Japan
K. Nakamura, Chubu University, Japan
M. Kobayashi, ANELVA Corporation, Japan
K. Sasaki, Nagoya University, Japan
Correspondent: Click to Email
Ionized physical vapor deposition (IPVD) is a key technology in the formation of seed and/or barrier layers on the surfaces of trenches and holes with high aspect ratios. In IPVD, metal atoms sputtered from the target are ionized in the gas-phase, and metal ions are accelerated toward the biased wafer by the sheath electric field. To optimize this technique, it is necessary to know ionization processes of metal atoms. In the present work, we measured the density distributions of Ti and Ti@super +@ in dc magnetron discharges by laser-induced fluorescence imaging spectroscopy. We observed significant production of Ti@super +@ in the gas phase in high-pressure (@>=@100 mTorr) discharges. The distribution of the Ti@super +@ density had a peak at a distance of 5-6 cm from the target surface. Namely, the production of Ti@super +@ was obtained in dark plasma with a low electron temperature, and was not obtained in bright region near the target with a high electron temperature, indicating that electron impact ionization of Ti is not the production process of Ti@super +@. As another possible candidate of the production process of Ti@super +@, we investigated Penning ionization (collision between Ti and Ar@super M@) by measuring the density distribution of Ar at a metastable state (Ar@super M@). In addition, we estimated the density ratio between Ti@super +@ and Ar@super +@ from the total plasma density measured using a Langmuir probe. The result suggests that Ti@super +@ is the dominant ion in the down flow region of the high-pressure discharge.