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

Paper PS-ThM7
Sources of Asymmetry in Ionized Metal PVD Reactors@footnote 1@

Thursday, November 5, 1998, 10:20 am, Room 318/319/320

Session: Plasma Applications in Copper Metallization
Presenter: J. Lu, University of Illinois, Urbana-Champaign
Authors: J. Lu, University of Illinois, Urbana-Champaign
M.J. Kushner, University of Illinois, Urbana-Champaign
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Ionized metal physical vapor deposition (IMPVD) can produce highly ionized metal fluxes for use in filling high-aspect-ratio vias and trenches in microelectronic devices. A typical IMPVD reactor uses inductively coupled plasma (ICP) excitation in conjunction with a dc or rf magnetron. Directionality, uniformity, and high deposition rate are the most desired properties in the deposition process. One factor that significantly affects the cited properties is the symmetry of excitation and sputtering in the IMPVD reactor. Asymmetries may be caused by nonuniform erosion of the target, asymmetric gas injection and/or pumping, or non-uniformities in the inductively coupled field due, for example, to transmission line effects. These asymmetric processes couple nonlinearly with each other. In this paper, sources of asymmetry in metal deposition will be numerically investigated. The computational tool used in this study is the three-dimensional Hybrid Plasma Equipment Model (HPEM), in which a Monte Carlo sputter model is coupled self-consistently to the plasma simulation. The reactor being modeled uses an external coil (made possible by a Faraday shield). Typical operating conditions are 10 mTorr gas pressure, 1kW ICP power, and 13.6MHz frequency. The uniformity of the ion flux and ionization fraction for Cu and Al IMPVD systems will be discussed as a function of aspect ratio, target geometry and antenna design. @FootnoteText@ @footnote 1@Work supported by SRC, Materials Research Corporation, and NSF.