Classification of impact-assisted etch mechanisms

Abstract

Previously, a mechanistic framework has been constructed for impact-assisted etch reactions in e.g. Reactive Ion Etching. The consecutive reaction steps (adsorption, surface reaction and product desorption) are assumed to be activated thermally and in parallel mechanically by fast particle impacts. The rate determining step in the etch mechanism determines the etch profile. The framework discerns four basic types of etching. In this work, the etch mechanisms of Fe/FeCrB multilayers, quartz, alumina, zirconia, magnesia and silicon have been studied in an HCl plasma (Alcatel GIR300) as a function of pressure, RF input power and surface temperature. With the help of our framework the results can be rationalized and a proper choice of etch conditions is possible.