IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Manufacturing Science and Technology Tuesday Sessions
       Session MS-TuA

Paper MS-TuA9
In-situ FTIR Spectroscopy for Metrology of a Tungsten CVD Process

Tuesday, October 30, 2001, 4:40 pm, Room 131

Session: In Line and In Situ Process Control
Presenter: A. Singhal, University of Maryland
Authors: A. Singhal, University of Maryland
L. Henn-Lecordier, University of Maryland
J.N. Kidder, University of Maryland
C.A. Gogol, Inficon, Inc.
J.F. Kushneir, Inficon, Inc.
Correspondent: Click to Email
A Fourier Transform Infrared Spectrometer has been employed for downstream detection of reactants and reaction products in a tungsten chemical vapor deposition process. The objective of this work was to monitor reactant and product concentrations for metrology of the deposition rate on the wafer. The spectroscopy system includes a novel compact interferometer and a heated optical cell with purged optics. Measurements of the gas composition directly downstream of the wafer were done using a pumped sampling system to extract gases from the low pressure CVD process to the optical cell. Experiments showed a linear correlation between the gas concentration in the deposition chamber and the intensity of absorption features detected at the sampling optical cell. In experiments with repeated wafer load/unload and process flow sequences there was no significant drift in the detected steady-state intensity of absorption peaks. In measurements done during deposition process runs at a range of conditions the intensity of absorption features associated with a reactant (WF@sub 6@) and a principal reaction product (HF) were detected and correlated to the weight gain on the wafer for in-situ metrology of the deposition rate.