AVS 50th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP12
Surface and Gas-phase Reactions in Plasma CVD using Cu(EDMDD)@sub 2@ as Source Material

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: K. Takenaka, Kyushu University, Japan
Authors: K. Takenaka, Kyushu University, Japan
M. Takeshita, Kyushu University, Japan
M. Kita, Kyushu University, Japan
K. Koga, Kyushu University, Japan
M. Shiratani, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
T. Shingen, Asahi Denka Kogyo K.K., Japan
Correspondent: Click to Email
We have demonstrated 1) deposition of Cu films which have a low resistivity of 1.85 µ@ohm@cm and a strong adhesion strength above 10 MPa to the TiN layer, and 2) conformal deposition of smooth Cu films of 20 nm in thickness in trenches 0.5 µm wide and 2.73 µm deep using H-assisted plasma CVD (HAPCVD), which has an advantage of controlling independently concentrations of Cu-containing radicals and H atoms.@footnote 1@ To obtain information on surface and gas-phase reactions in HAPCVD, we have studied electron impact dissociation processes of Cu(EDMDD)@sub 2@ as well as nucleation and island growth of Cu, which are closely related with smoothness of Cu films and their adhesion strength to their under-layer. Quadrupole mass spectroscopic measurements show that Cu(EDMDD)@super +@ is the dominant ionic product from Cu(EDMDD)@sub 2@ due to an electron impact at electron energy of 70 eV. Based on this result together with the ion-core model, Cu(EDMDD) is suggested to be the main neutral radical from Cu(EDMDD)@sub 2@ due to electron impact dissociation. In-situ FT-IR measurements also show that supply of H atoms to the surface of deposition film is quite effective in reducing its impurity concentration. Nucleation density has little dependence on the kind of materials of under-layer such as TiN, TaN, WN, and Si. The nucleation rate increases from 2.3x10@super 14@ m@super -2@s@super -1@ at the substrate temperature T@sub s@ = 120°C to 4.1x10@super 14@ m@super -2@s@super -1@ at T@sub s@ = 220°C with increasing T@sub s@, while a maximum nucleation density of 3x10@super 16@ m@super -2@ is obtained at T@sub s@ = 150°C. The maximum density is more than two orders of magnitude higher than that for thermal CVD, and the high density is considered to contribute to smoothness and high adhesion strength of Cu films. @FootnoteText@ @footnote 1@ K. Takenaka, et al., Proc. of ISTC 2002 (in press).