Method and materials for etching silicon dioxide using silicon nitride or silicon rich dioxide as an etch barrier

摘要

A process for etching Si02 using either silicon rich SiO2 or Si3N4 as an etching barrier over a substrate. Selectivity is obtained between the two dielectric materials, silicon dioxide and silicon nitride or silicon dioxide and silicon rich silicon dioxide wherein the oxide etches considerably faster than nitride (or silicon rich silicon dioxide) because of the selectivity of oxide to nitride. A further object of the present invention is to provide an etching process wherein the silicon dioxide on the substrate is directionally etched in a fluorocarbon gas to form silicon dioxide spacers on a substrate, and the substrate surface ist protected by an etch stop composed of the silicon nitride or silicon rich silicon dioxide material.