AVS 46th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeM

Paper PS-WeM3
Investigation through Simulation of the Effect of Ar Addition on the Cl@super +@/Cl@sub 2@@super +@ Ratio in Chlorine Discharges

Wednesday, October 27, 1999, 9:00 am, Room 609

Session: Feature Profile Evolution
Presenter: J. Helmsen, Applied Materials Inc.
Authors: J. Helmsen, Applied Materials Inc.
P. Loewenhardt, Applied Materials Inc.
Correspondent: Click to Email
.A cause of compromise in commercial Al etch processes that employ Cl discharges is the removal of Cu residue. This residue is due to the presence of Cu that has been added to the Al to prevent electromigration. Investigation of processes that successfully remove this residue have shown that the Cl@super +@/Cl@sub 2@@super +@ ratio measured near the wafer has been found to positively correlate with residue removal.@footnote 1@ This ratio can increase as a result of lower pressures and increased source powers, but also can increase due to the addition of Ar into the plasma. Investigation of the ratio through the use of simulation in pure Cl plasmas has shown the ratio is controlled by charge exchange between Cl@super +@ and Cl@sub 2@ producing Cl@sub 2@@super +@ and Cl.@footnote 2@ The proposed influence of Ar is dilution of Cl@sub 2@, thereby allowing a greater proportion of Cl@super +@ to not participate in the reaction and reach the surface. The effect is shown through the use of plasma simulation with the Hybrid Plasma Equipment Model (HPEM).@footnote 3@ @FootnoteText@ @footnote 1@ P. Loewenhardt, "Plasma Diagnostics: Use and Justification in an Industrial Environment", 51st Annual Gaseous Electronics Conference, Maui, Hawaii, Oct. 1998. @footnote 2@ J. Helmsen, D. Hammer, J. Yamartino and P. Loewenhardt, "Investigations of Rate Coefficients in the Cl Model", IEEE Transactions on Plasma Science (Accepted for Publication) @footnote 3@ P. L. G. Ventzek, M. Grapperhaus and M. J. Kushner, "Investigation of Electron Source and Ion Flux Uniformity Measurements in High Plasma Density Inductively Plasma Tools Using 2-Dimensional Modeling", J. Vac. Science Tech. B 12, 3118-3137 (1994)