AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoA

Paper TF-MoA10
Analysis of Mode Transistions in I-PVD and Conventional PVD Reactive Sputtering of Refractive Diffusion Barrier Materials

Monday, October 25, 1999, 5:00 pm, Room 615

Session: Fundamentals and Applications of Ionized PVD
Presenter: J. Norman, University of Illinois, Urbana-Champaign
Authors: D.R. Juliano, University of Illinois, Urbana-Champaign
R. Ranjan, University of Illinois, Urbana-Champaign
D.N. Ruzic, University of Illinois, Urbana-Champaign
J. Norman, University of Illinois, Urbana-Champaign
Correspondent: Click to Email
I-PVD techniques have shown to be effective for the deposition of contact, barrier, adhesion and seed layers. For copper metallization such layers include Ti, Ta, TiN and TaN. In conventional PVD processes, reactive sputtering techniques have shown two important deposition modes, namely, metallic and poison modes. In the metallic mode the nitration occurs on the substrate whereas in the poison mode it occurs on both the target and the substrate. There are advantages and disadvantages of each. Mode transitions are compared between I-PVD and conventional PVD sputtering processes. The analysis includes measurements of plasma temperature and density using Langmuir probe techniques, as well as ionization fractions and deposition rates. A dc planar magnetron with a 33-cm diameter target is coupled with a secondary plasma source to ionize the sputtered metal neutral flux to control the angular distribution of the flux arriving at the surface of the substrate. The secondary radio-frequency (rf) plasma is created between the sputtering target and the substrate by a multi-turn coil located in the vacuum chamber. The rf plasma increases the electron temperature and density, which results in significant ionization of the neutral metal flux from the sputtering target. By applying a small negative bias to the substrate, metal ions are drawn to the substrate at normal incidence. A gridded energy analyzer and a quartz crystal microbalance (QCM) are embedded in the substrate plane to allow the ion and neutral deposition rates to be determined.