AVS 46th International Symposium
    Manufacturing Science and Technology Group Monday Sessions
       Session MS-MoA

Paper MS-MoA4
Generation of Positively Charged Particles at an Anode and Transport to Device-wafers in a Real rf-plasma Etching Chamber for Tungsten Etch-back Process

Monday, October 25, 1999, 3:00 pm, Room 611

Session: Ultra-Clean Society and Contamination Free Manufacturing
Presenter: T. Moriya, NEC Corporation, Japan
Authors: T. Moriya, NEC Corporation, Japan
N. Ito, NEC Corporation, Japan
F. Uesugi, NEC Corporation, Japan
Y. Hayashi, NEC Kyushu, Ltd., Japan
K. Okamura, NEC Kyushu, Ltd., Japan
Correspondent: Click to Email
In this paper, it is clarified that the particles, flaked off from a grounded anode of parallel-plate rf plasma etching equipment, have positive charges. Moreover, the particles transport from the anode to the device-wafer on the cathode with keeping away from bulk plasma. In previous papers, we have reported that, in the middle space between the two electrodes, many particles were observed at the timing of the rf power off, and seemed to be drawn to the wafer with the residual negative self-bias voltage.@footnote 1,2@ To clarify the polarity of charge and the transport path of particles, the appearances and the trajectories in relation to the workings of the etching equipment are studied in detail both near the anode and the device-wafer on the cathode. Surprising results are obtained. Near the grounded anode, a few particles appear constantly and have parabolic trajectories with open upward in the duration of rf power, and many particles appear and have sharply curved trajectories from the anode to the chamber wall at the rf power off. On the other hand, near the wafer on the cathode, almost all particles appear at the rf power off and are drawn from the chamber wall to the wafer. These results mean the particles are reflected by the plasma potential, and they transport from the anode to the wafer with keeping away from the residual bulk plasma under the existence of attractive force between the particles' positive charge and the residual negative charge of the wafer. @FootnoteText@ @footnote 1@F. Uesugi, et al., J. Vac. Sci. Technol. A 16, 1189 (1998).@footnote 2@N. Ito, et al., J. Vac. Sci. Technol. B 16, 3339 (1998).