Method for STI etching using endpoint detection

摘要

A method for dry etching a feature to control an etching depth using endpoint detection and a sacrificial hardmask including providing a substrate for etching a feature opening into said substrate, said substrate provided with at least a first dielectric layer overlying the substrate; providing at least a second dielectric layer including a sacrificial hardmask at a predetermined thickness over the at least a first dielectric layer; photolithographically patterning and etching in a first dry etching process through a thickness of the at least a second dielectric layer and the at least a first dielectric layer to expose the substrate for dry etching the feature opening; and, dry etching in a second dry etching process the substrate and the sacrificial hardmask layer to endpoint detection of an underlying layer with respect to the sacrificial hardmask layer to thereby etch through a predetermined thickness of the substrate.