Reactive Ion Etching of Silicon with Cl2 / Ar ( 1 )

Abstract

A study of the use of reactive chlorine species for etching silicon and silicon dioxide in a plasma etching process has been made with a gas mixture in a cathode‐coupled diode system. A key advantage of the gas mixture is the ability to achieve high etch rate ratios between silicon and silicon dioxide (≥ 20:1) coupled with no mask undercutting, which tends to be prevalent with fluorinated gas systems. Etching characteristics of Si as a function of process parameters ( concentration, pressure, system loading) and material parameters (e.g., Si conductivity, edge shape of mask) have been evaluated. These parameters can influence the silicon etch rate, the etch rate ratio, as well as the etched edge shape.