IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Monday Sessions
       Session PS1-MoA

Paper PS1-MoA5
Study of Surface Reaction of SiO@sub 2@ Etching by Plasma Beam Irradiation

Monday, October 29, 2001, 3:20 pm, Room 103

Session: Plasma-Surface Interactions I
Presenter: K. Kurihara, Association of Super-Advanced Electronics Technologies (ASET), Japan
Authors: K. Kurihara, Association of Super-Advanced Electronics Technologies (ASET), Japan
Y. Yamaoka, Association of Super-Advanced Electronics Technologies (ASET), Japan
M. Sekine, Association of Super-Advanced Electronics Technologies (ASET), Japan
M. Nakamura, Association of Super-Advanced Electronics Technologies (ASET), Japan
Correspondent: Click to Email
Fluorocarbon gases are widely used for Si/SiO@sub 2@/SiN etching to achieve high etching performance. The SiO@sub 2@ etching mechanism has been studied for the last three decades by using etching reactors and beam apparatuses. Multi-beam (ions and/or radicals) experiments are useful for understanding the surface reaction by simplifying beam-surface interaction. However, the plasma surface reaction in the etching reactor is very complicated because of many kinds of ions and radicals especially for fluorocarbon gas case. We have constructed a plasma-beam irradiation apparatus to examine the plasma-surface reactions under a real etching environment. Our plasma source can control plasma parameters, such as ion energy, residence time of introduced gases, radical/ion composition, and the ratio of a neutral flux to an ion flux. Desorbed products from the SiO@sub 2@ substrate were measured by a quadrupole mass spectrometer (QMS) during CF@sub 4@/Ar gas mixture plasma beam irradiation. The desorbed products from SiO@sub 2@ are assumed to be SiFx, COFx, (x=1-3), CO, CO@sub 2@ etc. However, SiFx and COFx can not be detected separately by QMS because they have the same atomic mass. Therefore, CF@sub 4@ gas which consists of isotope C@super 13@ was used as an etching gas in order to discriminate between SiFx and COFx. It was found that major Si containing desorbed products were SiF@sub 2@ and SiF@sub 4@. Their composition, furthermore, did not strongly depend on the ion energy in the range from 300eV to 800eV. After the plasma-beam irradiation, the surface of the substrate was examined by an in-situ XPS analysis. The fluoro-carbon (CF) layers on the SiO@sub 2@ were very thin, about 0.1-0.2 nm. The thicknesses of CF layer and their properties (F/C ratio and binding states) were found to be not dependent on the ion energy. This work was funded by NEDO.