Method for processing substrates using gaseous silicon scavenger

A plasma etch process comprising;

• a) providing a vacuum chamber for generating a plasma;
• b) supporting an article to be processed on a support in the chamber;
• c) supplying a fluorine-containing gas to the chamber;
• d) supplying a silicon-containing gas to the chamber so as to form a passivating polymer on the surface of said article;
• and
• e) coupling RF energy into the chamber for maintaining a plasma in said chamber for processing said article.

A plasma etch process comprising:

• a) providing a vacuum chamber for forming and maintaining a plasma therein;
• b) providing an article having an oxygen-containing layer over a non-oxygen-containing layer thereon to be processed by said plasma on a support in said chamber;
• c) supplying a fluorine-containing etch gas to the chamber;
• d) coupling RF energy into the chamber for forming and maintaining a plasma of said etch gas in the chamber;
• and
• e) supplying to the chamber a fluorine-consuming silicon or carbon-containing gas in addition to said etch gas so as to form a selectivity-enhancing polymer on said article to selectively etch the oxygen-containing layer.