Study of Metal Etching using Ozone Water

Abstract

We have proposed and experimentally demonstrated an environmentally friendly, simple, and inexpensive etching method for metal by ozone water. We experimentally measured the dependencies of ozone water etching on the temperature and ozone concentration for several metals (Cr, Ni, Al, Au, and Ti) and we also evaluated the surface roughness of the etched surface. The etching mechanism by ozone water can be explained by activation energy obtained by Arrhenius plot and a pH-potential diagram. As a result, it was found that the etching rate was proportional to the dissolved ozone concentration and temperature and that atomically flat surface was obtained after etching with ozone water, even though it was found that the etching rate was very low at a few tens of nanometers per hour. It is therefore difficult to use it for performing conventional macro- and micro-scale etching, whereas its rate is sufficiently high to use it for the nanoscale (i.e., a few tens of nanometers) metal etching in nanoscience and nanotechnology.