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    Electronics Friday Sessions
       Session EL-FrM

Paper EL-FrM4
An Investigation of Compound and Non-compound Forming Dilute Binary Cu-Alloy Thin Films

Friday, November 2, 2001, 9:20 am, Room 124

Session: ULSI Metallization & Interconnects
Presenter: A. Gungor, Carnegie Mellon University
Authors: A. Gungor, Carnegie Mellon University
K. Barmak, Carnegie Mellon University
C. Cabral, IBM T.J. Watson Research Center
C. Lavoie, IBM T.J. Watson Research Center
J.M.E. Harper, IBM T.J. Watson Research Center
Correspondent: Click to Email
The control of microstructural features such as grain size and texture in very narrow copper interconnections is increasingly important as dimensions reach the 100 nm range. This is because the resistivity must be minimized, yet other properties including adhesion and resistance to void formation need continued improvement, which will require alloying additions to copper. We have undertaken a detailed investigation of dilute binary Cu alloy films, and in this paper we report on six systems, three of which, Cu-Al, -In, and -Ti, are compound forming and the other three of which, Cu-Ir, -Nb, and -W, are non-compound forming. We find that annealing results in the lowest resistivity and the strongest <111> fiber texture in Cu(Ti), while the largest grain size is seen in Cu(In) films. In addition, in previous work@footnote 1@ we have shown that the dissociation mode of the non-compound forming alloys can be categorized using the Cu-rich end of the respective binary phase diagrams and the resistance-temperature behavior of the alloy films. Based on this classification scheme, we will show that Cu-W belongs to category III since its resistance-temperature plots show multiple drops as seen for other alloys in this category, while Cu-Ir belongs to category II. The classification of Cu(Ir) is based on its high temperature behavior, whereby the resistance increase is a result of solute re-dissolution and not a result of agglomeration. @FootnoteText@ @footnote 1@ K. Barmak, G. A. Lucadamo, C. Cabral, Jr., C. Lavoie, and J. M. E. Harper, J. Appl. Phys.87, 2204 (2000).