Plasma etching

The term ‘plasma etching’ refers to anisotropic etching by means of chemical reaction for removing material layers. Other commonly used and more specific designations are reactive plasma etching, reactive dry etching, and chemical plasma etching. In plasma etching, the surface of a substrate is removed by chemical reaction with the process gas. In particular the high reactivity of the excited atoms and molecules and specifically the radicals is used. Often, oxygen is used as a process gas. The etching rate on the different substrates differs greatly (“selective”). Oxygen plasma does not etch surfaces which are already oxidised. Applications:

• Removal of hydrocarbons (also ⇒ Plasma cleaning)
• Etching of PTFE
• Removal of material surfaces
• Roughening and surface increase
• Removal of photoresists (photoresist stripping)

The physical etching effect of the ion bombardment (see ⇒ Ion etching, RIE) is not used.