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 PS-MoP

Paper PS-MoP9
Uniformity Control of Electron Temperature and Density within a Commercial-scale Helicon Plasma Processing Reactor

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Plasma Diagnostics and Plasma-Surface Interactions Poster Session
Presenter: M.J. Neumann, University of Illinois at Urbana
Authors: M.J. Neumann, University of Illinois at Urbana
J.E. Norman, University of Illinois at Urbana
D.N. Ruzic, University of Illinois at Urbana
Correspondent: Click to Email
A study of electron temperature and density profiles was performed with PlasmaQuest 256 helicon plasma processing research reactor to better understand power absorption within a plasma reactor operating in helicon mode. The plasma source is a PMT Mori 200 antenna, coupled with an inner and outer opposing magnetic field coil placed around the it and a third coil positioned below it. The use of external magnetic field coils gives the ability to quickly change from one operating mode and condition to another. External electrical and magnetic variation effects are observed with a radially and z-varying Langmuir probes and spectroscopy. For nitrogen at 800 W RF and 80 A on the inner and lower magnets, the electron density profile was seen to decrease inward from 1.1x10@super 11@ cm@super -3@ at the edge of the chamber to 6.0x10@super 10@ cm@super -3@ in the center, while the electron temperature increased inward from 1.0 eV to 4.8 eV at the center of the chamber. In contrast, at 800 W RF and 40 A on the inner magnet alone, the electron density profile was seen to increase inward from 2.0x10@super 10@ cm@super -3@ at the edge of the chamber to a peak of 7.0x10@super 10@ cm@super -3@, while the electron temperature decreased inward from 4.0 eV to 2.6 eV at the center of the chamber. Through manipulation of electron density and temperature, the surface properties of various biopolymers can be changed, while leaving the underlying material unchanged. One observable change is a decrease in the water contact angle with common biopolymers, such as low-density polyethylene and high-density polyethylene. These changing plasma conditions have also been observed with argon and oxygen. Modeling has been performed to show the physical mechanisms involved in the electromagnetic energy transfer to the plasma. Thus, within the same reactor chamber and via only external manipulation, very distinct plasma conditions yielding different interaction properties can be produced.