Etching

What is an advantage of pulsed plasma, which etches while switching the RF power on and off?

  1. AEtching equipment becomes unnecessary
  2. BThe wafer is kept heated
  3. CElectron temperature and ion energy are easier to control, making charging and damage easier to suppress
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Answer: C. Electron temperature and ion energy are easier to control, making charging and damage easier to suppress

In pulsed plasma, the electron temperature drops while the power is off and negative ions form, helping neutralize charge on the wafer surface. Ion energy and the ratio of radical species are also easier to adjust, so it is used to suppress damage and profile defects in fine patterning.

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More Etching questions

  1. Which gases are commonly used for dry etching of GaN?
  2. Why is it difficult to pattern copper wiring directly by dry etching?
  3. In gate etching, what is the phenomenon called in which the pattern sidewall is undercut laterally near the boundary with the underlying insulator?
  4. Why are reaction products (polymers) left on pattern sidewalls removed after dry etching?
  5. What is needed to etch oxide and stop on the nitride underneath?