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

Paper TF-MoA6
Ionized Physical Vapor Deposition (PVD) using Hollow-Cathode Magnetron (HCM) Source for Advanced Metallization

Monday, October 25, 1999, 3:40 pm, Room 615

Session: Fundamentals and Applications of Ionized PVD
Presenter: E. Klawuhn, Novellus Systems, Inc.
Authors: E. Klawuhn, Novellus Systems, Inc.
G.C. D'Couto, Novellus Systems, Inc.
K.A. Ashtiani, Novellus Systems, Inc.
P. Rymer, Novellus Systems, Inc.
M.A. Biberger, Novellus Systems, Inc.
K.B. Levy, Novellus Systems, Inc.
Correspondent: Click to Email
Ionized Physical-Vapor Deposition (I-PVD) has been recognized as the technology of choice for extending the application of PVD processes to < 0.25 µm device geometries. However, due to the complexity of the conventional RF I-PVD, these sources are not in widespread manufacturing use. The Hollow-Cathode Magnetron (HCM) source is a new and promising technology that maintains the simplicity of the PVD technology and combines it with a very high-density diffused plasma (> 10@super 12@ #/cm@super 3@) for efficient ionization of sputtered metals. The HCM is based on the principle of charged particle magnetic mirror applied to an inverted cup shaped target. As such, it does not require any additional RF or microwave sources for generation of metal ions. The HCM source was used for deposition of Ti(N), Ta(N), and Cu films. Excellent bottom coverage (20 % for Cu, 40% for Ta and 30 % for Ti) in narrow, high aspect ratio vias (0.25µm, 5:1 AR) was obtained without the application of RF bias to the wafer. Since reactive processes were run in a non-poisoned mode, both TiN and TaN films had the same step coverage as Ti and Ta films, respectively. The TiN film resistivity is of the order of 30 µ@ohm@-cm (for a 1000 Å film) and close to the theoretical bulk resistivity of 18 µ@ohm@-cm. The HCM films have strong crystallographic orientation, <002> <111> <002> and <111> for Ti, TiN, Ta, and Cu respectively. RF bias was utilized to increase the bottom coverage and the sidewall coverage of the films, thus extending the technology to higher aspect ratios. In addition, RF bias was used to modify film properties such as grain size, grain orientation, and film texture. In this paper, the HCM theory of operation will be reviewed and results will be presented for the application of this source for deposition of Ti(N), Ta(N), and Cu films. In addition, the effects of RF bias on step coverage and film properties will be discussed.