Estimation of Ion/Radical Flux from Mask Selectivity and Etching Rate Calibrated by Topography Simulation

概要

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A simple method for the estimation of ion/radical fluxes in an ion-assisted etching process was developed for SF6/O2/Si etching utilizing the difference in etching mechanism between SiO2 mask and the silicon substrate. It was derived that F coverage of a silicon surface is approximately a linear function of the selectivity of the two materials, from which the incident ion flux and F flux are calculated. The selectivity-to-coverage proportional constant was determined using a topography simulator so that the general trend of etching profiles matched those of the experiment. The obtained fluxes showed reasonable qualitative trends in terms of reactor operational conditions and reactor parameters. The feature profiles simulated by the topography simulator using these flux values were in good agreement with those of scanning electron microscopy (SEM) experimental data over a wide range of operating conditions and machine configurations.
2011-08-25