AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS-TuM

Paper PS-TuM11
Conformal and Anisotorpic Deposition of Cu Films using H-assisted Plasma CVD

Tuesday, November 5, 2002, 11:40 am, Room C-103

Session: Atmospheric Pressure and Other Emerging Plasma Applications
Presenter: M. Shiratani, Kyushu University, Japan
Authors: M. Shiratani, Kyushu University, Japan
K. Takenaka, Kyushu University, Japan
M. Onishi, Kyushu University, Japan
K. Koga, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
T. Shingen, Asahi Denka Kogyo K.K., Japan
Correspondent: Click to Email
We have developed H-assisted plasma CVD (HAPCVD),@footnote 1,2@ which realizes conformal and anisotropic deposition of Cu films in trenches for Cu interconnects of small width below 100 nm. Conformal deposition is aimed at creating thin Cu seed layer for Cu electroplating, while anisotropic deposition is aimed at filling trenches completely. We have obtained the results 1-4) using fluorine(F)-free complex, Cu(EDMDD)@sub 2@ and the result 5) using Cu(HFAC)@sub 2@. The following conclusions are obtained in this study. 1) H irradiation is effective in removing impurities from the surface and inside of Cu films for a substrate temperature above 170°C. 2) Initial nucleation densities of Cu on TiN, TaN, and SiO@sub 2@ layers are above 5x10@super 15@ m@super -2@ which is quite high compared to those for thermal CVD. The high nucleation density is favorable to realizing smooth thin Cu films and their strong adhesion to under-layer. 3) Deposition of Cu films of a low resistivity, 1.85 µ@ohm@cm and a strong adhesion above 10 MPa to TiN diffusion barrier layer has been demonstrated. Concentrations of C and O in the Cu film are much less than 0.1%, while those values at the interface between Cu and TiN are 1 and 0.2%, respectively. 4) Conformal deposition of smooth Cu films of 20 nm in thickness in trenches 0.5 µm wide and 2.73 µm deep has been demonstrated. 5) Anisotropy, which is defined as a ratio of film thickness at bottom of trench to that at its side wall, increases from 100% to 550% with increasing energy of irradiating ions from 20 V to 220 V, while H-irradiation reduces anisotropy. Promising anisotropic filling of trenches 3.5 µm wide, 2.73 µm deep has been demonstrated. @FootnoteText@ @footnote 1@ M. Shiratani, et al., Sci. and Technol. of Adv. Mater. , 2, 505 (2001).@footnote 2@ K. Takenaka, et al., Proc. of Int. Symp. of Dry Process, pp.169 (2001).