IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Friday Sessions
       Session VST+MS-FrM

Paper VST+MS-FrM3
Enhancement of Dielectric CVD Remote Clean Competitiveness Through Improved Gas Utilization

Friday, November 2, 2001, 9:00 am, Room 125

Session: Semiconductor & Functional Coating Systems & Processes
Presenter: T. Nowak, Applied Materials, Inc.
Authors: T. Nowak, Applied Materials, Inc.
T. Tanaka, Applied Materials, Inc.
B.H. Kim, Applied Materials, Inc.
M. Seamons, Applied Materials, Inc.
K.B. Jung, Applied Materials, Inc.
Correspondent: Click to Email
Remote plasma cleaning of dielectric CVD process chambers has been shown to virtually eliminate emission of global warming gases, increase chamber throughput, and increase the lifetime of process chamber hardware. Nitrogen trifluoride (NF@sub 3@) is the principal precursor used in remote plasma cleaning applications because of the ease with which it is dissociated and the high atomic fluorine content achievable at the exit of the remote plasma source. The relatively high cost of NF@sub 3@, however, makes improvement of gas utilization during the remote clean and development of alternative chemistries critical to enhancing the competitiveness of this green manufacturing process. Building on earlier experimental work, we have developed process models and designed experiments to investigate fluorine radical loss mechanisms and utilization efficiencies within parallel plate plasma CVD reactors. Modeling was based on an iterative solution of a one-dimensional flow network with variable gas composition to model transport and recombination losses from the remote plasma source to the process chamber. Calculated values of the atomic fluorine concentration in the process chamber were verified experimentally by measuring etch rates on SiO@sub 2@ wafers. Using the results of the simulation we were able to develop more efficient remote clean processes that, depending on residue to be cleaned, reduce NF@sub 3@ consumption by up to 60% without impacting chamber throughput. In addition, we investigated C@sub 3@F@sub 8@ as an alternative feed gas for the remote clean. Experiments showed that cleaning rates on the order of 80% of NF@sub 3@-based cleans were achievable using C@sub 3@F@sub 8@.