In an apparatus for producing an electromagnetically coupled planar plasma comprising a chamber having a dielectric shield in a wall thereof and a planar coil outside of said chamber and adjacent to said window coupled to a radio frequency source, the improvement whereby a scavenger for fluorine is...http://www.google.com.au/patents/US5772832?utm_source=gb-gplus-sharePatent US5772832 - Process for etching oxides in an electromagnetically coupled planar plasma apparatus 
