rf plasma source using a magnetic line‐cusp field

• Published in: Review of scientific instruments 1993-09, Vol.64 (9), p.2434-2439
• Main Authors: Yamauchi, Kazuo, Takahashi, Keiji, Yabe, Eiji
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma production and heating; Plasma sources
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1143901

A large volume cylindrical radio frequency (rf) plasma source using a magnetic line‐cusp field has been developed for use in large scale plasma processing. In this type of plasma source, a capacitively coupled 13.56 MHz rf plasma is produced in the presence of a magnetic line‐cusp field. Three versions of the plasma source have been constructed and tested. The first version has a pair of peripheral rf electrodes placed outside the ionization chamber and is suitable for preparing a large volume uniform plasma. This plasma source can attain a useful area of plasma with 10% uniformity over a 30‐cm‐diam region. The second version is featured by parallel doughnut‐plate electrodes which form part of the chamber wall and serve as a high current source, where the electron density is proportional to the rf power, being equal to 4×1010 cm−3 at 400 W. The third version is a slab‐plasma source, which has a rectangular ionization chamber, a pair of rectangular magnetic coils, and a pair of rectangular rf electrodes, yielding an electron density of the order of 109 cm−3 for a 25 W rf power.