AVS 51st International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2-WeM

Paper PS2-WeM4
Potentials and Fields in a 300-mm Dual-Frequency Capacitively Coupled Plasma Reactor

Wednesday, November 17, 2004, 9:20 am, Room 213B

Session: Plasma Sources
Presenter: P.A. Miller, Sandia National Laboratories
Authors: P.A. Miller, Sandia National Laboratories
E.V. Barnat, Sandia National Laboratories
G.A. Hebner, Sandia National Laboratories
A.M. Paterson, Applied Materials
J.P. Holland, Applied Materials
T. Lill, Applied Materials
Correspondent: Click to Email
Dual-frequency capacitively coupled plasma reactors provide separate control over plasma generation and ion extraction. Usually, a vhf power supply (source) is used to generate and sustain the plasma and an hf power supply (bias) is used to extract ions. At present there is debate over the optimum choices for the two operating frequencies, and whether they should be applied to one or two electrodes. Higher frequencies facilitate plasma generation with mild and controllable dissociation of feed-gas molecules, but the attendant shorter wavelengths cause concern over spatial variations in plasma properties. Regardless of frequency choices, electrical nonlinearity of plasma sheaths causes harmonic generation and mixing of source and bias frequencies. These processes, and the resulting spectrum of frequencies, are as much dependent on electrical characteristics of matching networks as on the plasma sheath properties. We investigated such electrical effects in a 300-mm Applied-Materials plasma reactor. Data were taken for 13.56-MHz bias frequency (chuck) and for source frequencies from 30 to 160 MHz (upper electrode). An rf-magnetic-field probe (B-dot loop) was used to measure the radial variation of fields inside the plasma. We will describe the results of this work. This work was supported by Applied Materials and Sandia National Laboratories, a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.