AVS 53rd International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoM

Paper PS1-MoM11
Grain Size Effects on Plasma-based Copper Etch Process

Monday, November 13, 2006, 11:20 am, Room 2009

Session: Etch for Advanced Interconnect I
Presenter: G. Liu, Texas A&M University
Authors: G. Liu, Texas A&M University
Y. Kuo, Texas A&M University
Correspondent: Click to Email
Copper (Cu) is the most popular interconnect material in advanced VLSIC products because of its low resistivity and high resistance to electromigration. Previously, a novel plasma-based, room-temperature copper etching method was presented.@footnote 1,2,3@ A high etch rate of 400 nm/min has been achieved at room temperature using a conventional reactive ion etching reactor with Cl or Br chemistry. In spite of the thorough understanding of the plasma-Cu reaction process, there is little information on the copper structure effects. In this work, authors investigated the grain size effects on the etching process. Cu films were deposited by sputtering followed by annealing at various temperatures. Several results have been obtained: 1) the grain size and film conductivity increased with the annealing temperature, 2) under the same plasma exposure condition, the Cu consumption rate increased with the grain size, 3) the surface roughness of the CuClx reaction product increased with the grain size, and 4) the Cu line shape and sidewall profile were related to the grain size. In summary, Cu structure is an important factor in the plasma-based etching process and the plasma-copper reaction mechanism dominates the etch rate and the final pattern. @FootnoteText@ @footnote 1@ Y. Kuo and S. Lee, Appl. Phys. Lett., 78, 1002 (2001).@footnote 2@ S. Lee and Y. Kuo, Thin Solid Films, 457, 326 (2004).@footnote 3@ Y. Kuo, Procs. 6th Intl. Conf. Reactive Plasmas and 23rd Symp. Plasma Processing, 29 (2006).