AVS 45th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThP

Paper PS-ThP7
Electron and Negative Ion Density in BCl@sub 3@ / Cl@sub 2@ / Ar Gas Mixtures

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Plasma Science and Technology Division Poster Session
Presenter: G.A. Hebner, Sandia National Laboratories
Authors: G.A. Hebner, Sandia National Laboratories
M.G. Blain, Sandia National Laboratories
T.W. Hamilton, Sandia National Laboratories
C.A. Nichols, Sandia National Laboratories
R.L. Jarecki, Sandia National Laboratories
Correspondent: Click to Email
Electron and negative ion density have been measured in a modified Applied Materials DPS chamber using gas mixtures of BCl@sub 3@, Cl@sub 2@ and Ar. Measurements were performed for four different substrate types to examine the influence of surface material on the bulk plasma properties; aluminum, alumina, photoresist and Aluminum / PR. The plasma conditions of source power, bias power, pressure, Cl@sub 2@ / BCl@sub 3@ ratio, total flow rate and argon addition were varied over a wide operational parameter space. Electron densities in the Cl@sub 2@ / BCl@sub 3@ mixtures varied between 0.5 and 8.0 x 10@super 12@ cm@super -2@ or approximately 0.25 to 4 x 10@super 11@ cm@super -3@. Photodetachment measurements of the negative ion density indicate that the negative ion density is smaller than the electron density. In general, we noted that photoresist had a major influence on the electron and negative ion density. In most cases, the electron density above wafers with PR was a factor of two lower while the negative ion density was a factor of two higher than the aluminum or alumina surfaces. The trends observed in the DPS chamber were similar to trends observed in the previous measurements in the GEC rf reference cells at Sandia. The only exception was the pressure dependence of the electron and negative ion density. This difference in the two systems is likely related to the different coil configuration and geometry of the two chambers. This work was performed at Sandia National Laboratories and supported by SEMATECH, Applied Materials, and the United States Department of Energy (DE-AC04-94AL85000).