Etching

After the etch endpoint is detected, what is it called to continue etching for a set time to ensure the film is removed across the whole wafer?

  1. AOver-etching
  2. BAshing
  3. CDeposition
Show answer and explanation

Answer: A. Over-etching

Because of variation in etch rate and film thickness across the wafer, some film may remain when the endpoint is detected. Over-etching for a set time ensures complete removal. High selectivity is needed so that the underlayer is not over-etched in the meantime.

Practice this topic Back to topic

More Etching questions

  1. What is a mask of nitride, carbon or similar material called, used when photoresist alone cannot survive as a mask, such as when etching deep holes?
  2. Which is a characteristic of downstream etching, which supplies only plasma-generated radicals to the wafer?
  3. Which are examples of profile defects seen in high-aspect-ratio etching?
  4. If the oxide etch rate is 100 nm/min and the mask is consumed at 20 nm/min, what is the selectivity to the mask?
  5. Which solution, made by buffering hydrofluoric acid with ammonium fluoride, is used for wet etching of SiO2?