Low-pressure plasma cleaning: a process for precision cleaning applications

Low-pressure plasma cleaning is discussed as a precision cleaning method for high-quality applications in microelectronics, printed circuit board technology, the aircraft industry and medical applications. The main ability of low-pressure plasma cleaning is the removal of thin organic films from surfaces. Thick organic films or the presence of inorganic compounds limits the use of plasma and makes necessary a wet precleaning of the workpieces. Plasma cleaning, however, is the most suitable process for optimum surface cleanliness. As an impressive example, the precision cleaning of aluminium aircraft rims and engine parts of other metals prior to painting is presented. A low-pressure microwave plasma (f=2.45 GHz) is used and the results of the plasma treatment are discussed with respect to paint adhesion, weight loss, hydrogen embrittlement and changes in surface structure. (C) 1997 Elsevier Science S.A.