Remote microwave plasma source for cleaning chemical vapor deposition chambers: Technology for reducing global warming gas emissions

The semiconductor industry uses a large amount of perfluoro compounds (PFCs ), and their impact on global warming has become a major environmental conc ern. In the semiconductor industry, PFC are used to periodically remove dep osits from the chamber walls of chemical vapor deposition (CVD) reactors af ter film deposition. These chamber clean processes account for typically 50 %-70% of the PFC usage in a semiconductor wafer fabrication site, the rest being mainly used for wafer-etching processes. With a conventional parallel plate radio frequency (rf) plasma reactor, the PFC gas utilization is inco mplete and a large fraction of unreacted gas can be emitted in the atmosphe re. This paper describes a microwave plasma source that provides as high as 99.9% utilization removal efficiency (URE) of the reactant gas (NF3) durin g chamber clean. This technology brings the million metric tons carbon equi valent (MMTCE) of a chamber clean to negligible levels and also enhances th e chamber clean efficiency and the system throughput. Here we review the re quirements for the manufacturability of a remote plasma clean process. Gase ous Fourier transform infrared and quadrupole mass spectroscopy techniques have been used to characterize the clean process, the by-products of the re action, and the efficiency in reducing the MMTCE of CVD chamber cleans. (C) 1999 American Vacuum Society. [S0734-211X(99)06802-X].