Etching is a part of the PCB fabrication process which is used to create the cropper traces on the printed circuit board. This is done by removing the excess copper from the copper laminate, only leaving the required circuit on it.

There are two types of Etching: Dry Etching and Wet Etching:

Wet Etching: Wet Etching uses an acid solution and dissolves the unwanted copper based on chemical reactions. The unwanted copper is dissolved when dipped into a chemical solution. Successful realization of Wet Etching depends upon the selection of an appropriate chemical solution and etch material. 

There are two types of chemicals that can be used for Wet Etching:

• Acidic Chemicals: Ferric Chloride (FeCl₃) / Cupric Chloride (CuCl₂)
• Alkaline Chemicals: The chemicals used during Alkaline etching are chloride copper (CuCl₂ Castle, 2H₂O) + hydrochloride (HCl) + hydrogen peroxide (H₂O₂) + water (H₂O).

Dry Etching: This is also know as Plasma etching, where a plasma activates chemical reactions between base and surface atoms of the laminate causing the unwanted copper to dissolve.

The point at which all unwanted copper gets dissolved during etching is called ‘Breakpoint’.