Electrochemistry in anisotropic etching of silicon in alkaline solutions

Etching is the process of using an acidic or caustic chemical to cut into unprotected areas of a particular material. Initially used in the 15th century for decorating plate armor and sword blades, the metal surface (typically steel or copper) was first covered with a wax-like material. Part of the wax was removed to create decorative patterns. These were subsequently transfered into the metal by submerging the surface in an acid solution (the etchant). The German artist Daniel Hopfer is believed to be the first to use the etching process in printmaking, competing with the, at the time more common, engraving techniques. For artists, its great advantage lies in the simplicity of the technique which does not require special skills in metal working. Scratching the drawings directly into the waxlayer allowed for highly detailed etchings and prints. This technique has been used by many great artist throughout the centuries.