AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP7
Antennas for Large-Area, Inductively-Coupled Plasmas

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: M.M. Patterson, University of Wisconsin, Madison
Authors: M.M. Patterson, University of Wisconsin, Madison
A.E. Wendt, University of Wisconsin, Madison
Correspondent: Click to Email
Uniform plasma processing for large and noncircular substrates motivates the examination of design alternatives to the standard spiral antenna for inductively coupled plasmas. In addition to being unsuited for rectangular substrates, scaling of the spiral design suffers from several complications including increased voltage requirements@footnote 1@ (and therefore increased capacitive coupling). In addition, standing wave current variations along the length of the antenna exacerbate azimuthal nonuniformities along the increased spiral length.@footnote 2@ Therefore, we explore the feasibility of low inductance, scalable alternatives to the spiral design. We have constructed several rectangular antennas, 20 cm by 30 cm, from straight conductor segments, including serpentine and ladder shaped configurations. In the ladder configuration, neighboring parallel antenna segments carry currents in the same direction, while in the serpentine configuration, neighboring segments carry currents in opposite directions. Langmuir probe measurements of the spatial profiles of plasma properties show significant differences in the magnitude and uniformity of plasma density in argon discharges produced by these antennas. We will also present results from a circular serpentine antenna. Finally, as a means of understanding the differences between the antenna configurations, we have created and will present a simple model of the interference between the electromagnetic fields of neighboring parallel antenna segments. @FootnoteText@ @footnote 1@Jaeger EF, Berry LA, et al, Physics of Plasmas 2(6), 2597 (1995). @footnote 2@Kushner MJ, et al, J. Appl. Phys. 80(3), 1337 (1996).