AVS 45th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThM

Paper PS-ThM11
Scattering and Sputtering Processes of Energetic Ar@super +@ and Cu@super +@ Ions on Cu Surfaces: Molecular Dynamics Simulations

Thursday, November 5, 1998, 11:40 am, Room 318/319/320

Session: Plasma Applications in Copper Metallization
Presenter: C.F. Abrams, University of California, Berkeley
Authors: C.F. Abrams, University of California, Berkeley
D.B. Graves, University of California, Berkeley
Correspondent: Click to Email
Two competing technologies, electroplating and ionized PVD, show promise in filling narrow, high aspect ratio trenches and vias with copper. While energetic metal and inert gas ions play central roles in IPVD, they are potentially no less important in plating due to the need to deposit a high-quality seed layer of metal on top of a thin barrier layer before plating from solution can proceed. Therefore, a better understanding of how energetic Ar@super +@ and Cu@super +@ ions interact with copper surfaces is crucial for further development of both technologies. We present results of molecular dynamics (MD) simulations of Ar@super +@ and Cu@super +@ ions impacting model Cu surfaces with a variety of impact energies (50 - 200 eV) and angles. We modeled Cu-Cu interactions using the EAM potential energy function (PEF) and Ar-Cu interactions using the ZBL PEF.@footnote 1@ We report the distributions in reflected angles and energies for these ions. We report both total and differential sputter yields with respect to angle of ejection, and compare our MD results to recent experimental findings.@footnote 2@ The effect of changing ion energy and angle on these quantities is discussed. For example, we observe that the sputter yield for Ar@super +@ on Cu decreases as the Ar@super +@ ion's incident angle is increased from 30@super o@ to 60@super o@ from normal. These results shed light on the dynamics of low energy ion/metal surface interactions and provide a useful database of events for profile evolution simulations of Cu seed layer deposition and trench/via fill. @FootnoteText@ @footnote 1@ K. Gartner et al., Nucl. Instr. Meth. Phys. Res. B 102, p183 (1995). @footnote 2@ C. Doughty, S. M. Gorbatkin, and L. A. Berry, J. Appl. Phys. 82, p1868 (1997)