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

Paper PS-MoP5
Characterization of Inductively Coupled Discharges in C@sub 2@F@sub 6@ and CHF@sub 3@

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

Session: Poster Session
Presenter: G.A. Hebner, Sandia National Laboratories
Correspondent: Click to Email

The chloro-fluorocarbon gases C@sub 2@F@sub 6@ and CHF@sub 3@ are used in a number of microelectronic plasma processing systems for both oxide etch and surface passivation. To provide data on the fundamental plasma characteristics as well as plasma species, microwave interferometry has been used to measure the line integrated electron density, photodetachment spectroscopy was used to measure the negative ion density, and laser induced fluorescence (LIF) was used to measure the spatially resolved CF density. The measurements were performed in a GEC rf reference chamber with an inductive coil plasma source and rf wafer bias. Photodetachment measurements of the negative ions as a function of wavelength are consistent with the dominant negative ion being F-. Different trends between the negative ion density and the electron density show that the negative ion precursor species density depends on power, pressure and rf wafer bias, but not on the feed gas. By pulse modulating the plasma power, negative ion - positive ion recombination rates have been determined. Spatially resolved LIF measurements show the CF density peaking in the center of the C@sub 2@F@sub 6@ discharge but a more uniform radial distribution in CHF@sub 3@. CF density scaling with power, pressure, rf bias and surface material will be shown. This work was performed at Sandia National Laboratories and supported by SEMATECH and the United States Department of Energy (DE-AC04-94AL85000).