Modeling of Aluminum Etching in a Commercial High Density Plasma Reactor Using BCl_3/Cl_2/Ar Gas Mixtures

The predictive capability of numerical plasma reactor models depends sensitively on the accuracy of the plasma chemistry mechanisms, the database, and the surface chemistry that are included in the models. A comprehensive plasma-etch mechanism has been developed to describe the high-density plasma etching of aluminum in a BCl_3/Cl_2/Ar mixture. Results of extensive validation comparisons with experimental data (from various experiments at Sandia) are shown for several different reactor models (Aurora, MPRES, and PROTEUS) employing the aluminum-etch mechanism. Comparisons are made to both diagnostic measurements of the gas-phase as well as to wafer-etch data from a commercial reactor. The gas-phase chemistry and aluminum-etch mechanisms provide very good quantitative agreement between the models and the wide collection of observations and measurements available in this study over wide ranges of power, pressure, and gas mixture. Simulation results from the 2-D model predict well the measured radial uniformity for blanket-aluminum etching.