Process materials (gases and chemicals)

Which gases are mainly used for dry etching of silicon oxide (SiO2)?

  1. ANitrogen only
  2. BHelium only
  3. CFluorocarbon gases such as CF4 and C4F8
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Answer: C. Fluorocarbon gases such as CF4 and C4F8

Dry etching of SiO2 uses plasmas of fluorine-containing fluorocarbon gases, removing silicon as volatile SiF4. Many of these gases have high global warming potential, so after use they are decomposed in abatement systems before release.

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