The Plasma Etching of Polysilicon with  CF 3Cl / Argon Discharges: I . Parametric Modeling and Impedance Analysis

Abstract

A parallel plate plasma etching apparatus with extensive diagnostic capabilities has been constructed to study the plasma etching of heavily P‐doped polysilicon in Freon® 13 mixtures. A simple ac impedance model was used to estimate time‐averaged plasma properties; this model gave electron densities and sheath voltages in reasonable agreement with experimental evidence. Response surface methodology, an experimental design and statistical analysis tool, was used to efficiently obtain high quality empirical representations of the etching rate and total ion flux as functions of external parameters: power input, pressure, and composition.