Etching of oxide

HF In the semiconductor manufacturing process, buffered HE (BHF) and DHF are widely used for the etching of oxide layers and the removal of native oxide. Most polished surfaces will have a thin layer of oxide poly-Si, oxide, W, Cu, and so on. The removal of oxide by DHF could also help to remove metallic ions in oxide. DHF cleaning is also known to be very effective in removing particles trapped in recessed and eroded features. 

Plasma etchants are available for most of the films commonly used in micromachining. Etching of oxide, nitride, and silicon is usually done with fluorine-containing compounds such as SiF4, CF4, and SF6. Aluminum and other metals can be etched in chlorine plasmas such as SiC l4 and BC13. In certain conditions, better results can be obtained by combining several gases. 

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