Etching is the process of material being removed from a material’s surface. The two major types of etching are wet etching and dry etching (e.g., plasma etching).

The etching process that involves using liquid chemicals or etchants to take off the substrate material is called wet etching. In the plasma etching process, also known as dry etching, plasmas or etchant gases are used to remove the substrate material.

Dry etching produces gaseous products, and these products should diffuse into the bulk gas and be expelled through the vacuum system. There are three types of dry etching (e.g., plasma etching): chemical reactions (by using reactive plasma or gases), physical removal (generally by momentum transfer), and a combination of chemical reactions and physical removal.

On the other hand, wet etching is only a chemical process.