AVS 50th International Symposium
    Manufacturing Science and Technology Tuesday Sessions
       Session MS-TuM

Invited Paper MS-TuM5
Forming Laminar Cu/Substrate Interfaces: Vacuum vs. Electrochemical Processing

Tuesday, November 4, 2003, 9:40 am, Room 309

Session: Packaging and Role of Interface Engineering in IC Processing
Presenter: J.A. Kelber, University of North Texas
Authors: N.P. Magtoto, University of North Texas
J. Liu, University of North Texas
J. Lei, University of North Texas
X. Zhao, University of North Texas
J.A. Kelber, University of North Texas
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The nucleation and conformal growth of a Cu film on a metal or dielectric barrier substrate is of critical importance for the production of reliable interconnects. This phenomenon has been studied extensively at the vapor/solid interface, where surface science experiments carried out in vacuum or ultrahigh vacuum (UHV) can generally be applied directly to industrial thin film fabrication methods (e.g., sputter deposition). Such studies have demonstrated that the initial growth mode of Cu on various substrates is extremely sensitive to surface chemistry, and this can lead to highly variable results during real world processing. In many cases, including Si:C:H films,@footnote1@ silane-treated Ta,@footnote2@ and sapphire(0001),@footnote3@ initial 2-D growth on a dielectric or air-exposed metal substrate is enhanced by substrate hydroxylation prior to Cu deposition. This has important consequences for designing processes that are insensitive to incidental oxidation. In contrast, the situation at the electrolyte/solid interface is complex, and fundamental issues like the role of ad-atom mobilities or surfactants in film nucleation are not well understood. Kinetic measurements and in-situ STM provide only limited information.. This talk will review the enhancement of Cu 2-D growth at the vapor/solid interface, and discuss recent efforts to identify conformal vs. 3-D growth during electrodeposition, including the prospects for using monolayer concentrations of ad-atoms, such as iodine, to enhance conformal growth in additive-free environments. @FootnoteText@ @footnote1@. M. Pritchett, N. Magtoto, and J. Kelber, Thin Solid Films (in press) @footnote2@. X. Zhao, M. Leavy, N. P. Magtoto and J. A. Kelber , Thin Solid Films 415, 308 (2002) @footnote3@. C. Niu, K. Shepherd, D. Martini, J. Tong and J. A. Kelber, and D. R. Jennison and A. Bogicevic, Surface Science 465, 163 (2000).