Dry etching: From plasma ashing to quantum dots

Abstract

First applications of plasma etching in very large scale integration were reported in the literature 20 years ago. After reviewing the early days of dry etching, applications of this technique to high-resolution pattern transfer are illustrated by the fabrication of deep square-wave gratings with micron dimensions used in diffractive structures as well as submicron structures with large aspect ratio, both etched into SiO2 in CHF3 plasmas. The importance of pattern distortion by faceting effects, redeposition of sputtered material, and undercutting by isotropic etching is discussed. Modern developments like etching of deep trenches into Si and the fabrication of quantum dots are briefly outlined.