Etching Machines

Etching Machines

Etching machines employ a method of engraving on metal that uses acids, bases, or other chemically abrasive substances. Etching is also sometimes referred to as chemical milling. The two main types of etchants are liquid-phase ("wet") etchants and plasma-phase ("dry") etchants.

Wet etching machines have been used since the middle ages to decorate metals and to create a master for printmaking. Commonly used wet etchants for copper are ammonia, ammonium persulfate, and ferric chloride. Hydroflouric acid (HF) is a common etchant for silicon dioxide.

Plasma etching machines, on the other hand, are commonly used in semiconductor and circuit board manufacturing. In plasma etching, a high-speed stream of plasma is shot in pulses at a metal. The source gas for the plasma usually contains molecules rich in chlorine or flourine, and the etching takes place at pressures from 0.1 to 0.5 torr.

Ion milling or sputter etching is a form of plasma etching that takes place at lower pressures. In ion milling machines, the item is bombarded with ions from noble gases such as argon.