AVS 50th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS+TF-TuM

Invited Paper PS+TF-TuM7
Anisotropic Cu Deposition using Plasma Chemical Vapor Deposition

Tuesday, November 4, 2003, 10:20 am, Room 315

Session: Plasma Enchanced Chemical Vapor Deposition
Presenter: M. Shiratani, Kyushu University, Japan
Authors: M. Shiratani, Kyushu University, Japan
K. Takenaka, Kyushu University, Japan
M. Takeshita, Kyushu University, Japan
M. Kita, Kyushu University, Japan
K. Koga, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
Correspondent: Click to Email
We have demonstrated complete filling of trenches by anisotropic Cu deposition, in which Cu is filled preferentially from the bottom of the trenches, using plasma chemical vapor deposition.@footnote 1@ The key to realize the anisotropic deposition is kinetic energy and flux of ions irradiating on the surface, since the deposition rate increases with increasing the kinetic energy and fluxes. Previously, by using H-assisted plasma CVD we have realized conformal deposition of smooth 20 nm thick Cu films in trenches as well as conformal filling of trenches.@footnote 2@ Although the Cu films have a low as-deposited resistivity of of 1.85 µ@ohm@cm and a strong adhesion strength above 10 MPa to the TiN layer, conformal filling results in a small crystal grain size below half of the trench width and in a seam where impurities of high concentration remain. The anisotropic deposition offers a possibility to overcome such shortcomings for the conformal filling together with two additional interesting features. One is the fact that deposition rate increases with decreasing the width of a trench. The other is a self-limiting deposition by which deposition stops automatically just after filling completely a trench. This feature may realize a LSI fabrication processes without the chemical mechanical polishing, being attractive for the Cu-porous low-k interconnects. @FootnoteText@@footnote 1@ K. Takenaka, et al., Matr. Sci. Smiconductor Processing 5, 301 (2003).@footnote 2@ M. Shiratani, et al., Sci. and Technol. of Adv. Mater. 2, 505 (2001).