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

Paper PS-MoP25
Study on Effects of Ion Irradiation on Plasma Anisotropic Cu CVD using a Triode Discharge

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

Session: Poster Session
Presenter: K. Takenaka, Kyushu University, Japan
Authors: K. Takenaka, Kyushu University, Japan
T. Kaji, Kyushu University, Japan
K. Koga, Kyushu University, Japan
M. Shiratani, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
Correspondent: Click to Email
Plasma anisotropic CVD method can realize bottom-up filling of Cu in a trench without sidewall deposition. @footnote 1,2@ This method is promising for Cu metallization in ULSI, since it has a potential to fill extremely narrow trenches and holes with a high aspect ratio. In order to reveal the anisotropic deposition mechanism, we have studied the deposition profile on a Si substrate with trenches using a triode discharge, for which a grounded mesh is placed at 10 mm above the substrate to control flux of ions impinging on the substrate. Without ion irradiation, nothing is deposited on the top, bottom and sidewall. With irradiation of ions of a low energy below 12 eV, the deposition rate on the top is 2 nm/min; while that on the sidewall increases with a trench width W from 0 nm/min for W @<=@ 1500 nm to 0.25 nm/min for W = 3300 nm, and the deposition rate on the bottom increases with W from 0 nm/min for W @<=@ 700 nm to 0.9 nm/min for W = 3300 nm. These results suggest the following three items; 1) ion irradiation is necessary for the deposition, 2) low energy ions are hard to reach the bottom of a narrow trench, 3) a fraction of low energy ions impinge on the sidewall of a wide trench. The items of 2) and 3) indicate that a width and an aspect ratio of trench have an influence on kinetic energy and flux of ions reaching bottom and sidewall. Based on the results, effects of ion irradiation on the plasma anisotropic CVD will be discussed in the presentation. @FootnoteText@ @footnote 1@ K. Takenaka, et al., Mater. Sci. Semicond. Proc. 5 (2003) 301.@footnote 2@ K. Takenaka, et al., J. Vac. Sci. Technol. A22(4) (2004) in press.