Plasma cleaning

Plasma cleaning involves the removal of impurities and contaminants from surfaces through the use of an energetic plasma created from gaseous species. Gases such as argon and oxygen, as well as mixtures such as air and hydrogen/nitrogen are used. Lower energy plasmas are used for plasma cleaning versus plasma etching operations. The plasma is created by using GHz frequency electric fields to ionize a low pressure gas phase. The pressures of the gaseous species are typically below 1 torr. The energetic, ionic species react with species on the surface of the item to be cleaned, often producing gaseous products which can be removed by a vacuum system. The energetic species also clean the surface by collision with the surface, knocking off species from the surface. Very high temperatures are involved in the process. Prolonged or higher power plasma cleaning etches the surface, going beyond the 'cleaning' phase.

Plasma cleaning is a commonly used process in the semiconductor industry which has the advantage of being solvent free, thus producing less waste.