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-TuA8
Thickness Metrology and Real-Time End Point Control in W CVD using in-situ Mass Spectrometry@footnote 1@

Tuesday, October 30, 2001, 4:20 pm, Room 131

Session: In Line and In Situ Process Control
Presenter: S. Cho, University of Maryland
Authors: Y. Xu, University of Maryland
L. Henn-Lecordier, University of Maryland
T. Gougousi, University of Maryland
G.W. Rubloff, University of Maryland
S. Cho, University of Maryland
Y. Liu, University of Maryland
Correspondent: Click to Email
In-situ downstream mass spectrometry has been employed in W CVD processes for real-time reaction sensing, thickness metrology, and real-time end-point process control. In the silane reduction process for depositing W CVD from SiH@sub 4@ + WF@sub 6@ using an Ulvac ERA-1000 cluster tool, high reactant reactant conversion rates were obtained at 200-250°C. Both depletion of the SiH@sub 4@ reactant and generation of the H@sub 2@ and SiF@sub 4@ reaction products provided real-time thickness metrology signals which correlated with post-process, ex-situ film thickness measurements with an uncertainty better than 2%. These metrology signals were used as end-points to terminate the process in real-time, leading to corresponding control of the mass spectrometry derived signal even in the presence of random run-to-run process fluctuations and systematic drift intentionally introduced as a run-to-run temperature drift. Actual film thicknesses as measured post-process were controlled to within 3% using this mass-spec-based end-point control. These results demonstrate that downstream mass spectrometry provides real-time thickness metrology suitable for real-time as well as run-to-run process control. Furthermore, the real-time end pointing capability enables compensation for random process fluctuations as well as systematic process drift. @FootnoteText@ @footnote 1@Present affiliations: Y. Xu (IBM Microelectronics, Hopewell Junction, NY); T. Gougousi (North Carolina State University, Raleigh, NC).