Etching

Why are reaction products (polymers) left on pattern sidewalls removed after dry etching?

  1. ATo prevent defects in later steps and degradation of electrical characteristics
  2. BTo change the color of the wafer
  3. CTo make the wafer heavier
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Answer: A. To prevent defects in later steps and degradation of electrical characteristics

Polymer passivation left on sidewalls from etching can reduce adhesion of subsequent films, increase contact resistance and cause corrosion. It is therefore carefully removed by ashing and wet cleaning.

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More Etching questions

  1. What is needed to etch oxide and stop on the nitride underneath?
  2. What is the role of etching in semiconductor manufacturing?
  3. Which correctly describes the "plasma" used in dry etching?
  4. If etching proceeds at 100 nm/min for 3 minutes, how much film is removed?
  5. In wet etching, how does the etch rate generally change when the solution temperature is raised?