Process materials (gases and chemicals)

What is the operation called in which a gas line is repeatedly pressurized with inert gas and evacuated before it is opened or switched to another gas?

  1. ACycle purging
  2. BDry etching
  3. CAnnealing
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Answer: A. Cycle purging

Cycle purging repeatedly pressurizes the piping with an inert gas such as nitrogen and then evacuates or vents it, gradually diluting and driving out residual hazardous gas and moisture. It is done, for example, when changing toxic gas cylinders, to ensure safety and purity.

  • A. Correct. Repeated pressurizing and venting drives out residual gas.
  • B. Dry etching removes films.
  • C. Annealing is a heat-treatment step.
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