N. Korner et al., HYDROGEN PLASMA CHEMICAL CLEANING OF METALLIC SUBSTRATES AND SILICON-WAFERS, Surface & coatings technology, 77(1-3), 1995, pp. 731-737
The plasma chemical cleaning process based on an argon-hydro discharge
differs from conventional plasma cleaning methods. Chemical reactions
are used for the removal of surface contamination and the sputtering
of material is avoided. Therefore no problems due to the redeposition
of the sputtered material occur. The process chemistry is confirmed by
in situ measurements of the plasma during the cleaning procedure usin
g a plasma monitor. The process was investigated for bare copper lead
frames and for silicon wafers. Volatile hydrogen compounds were formed
during cleaning. An Auger spectrometer was attached to the cleaning c
hamber to investigate the substrate surfaces after each cleaning step.
It was shown that the carbon and oxygen contamination at the substrat
e surface could be reduced below 0.5 at.% (noise limit of the measurem
ent). The results clearly show that this simple and environmentally fr
iendly process is an effective method for reducing organic and some in
organic contamination.