Etching
Why are coatings such as yttrium oxide (Y2O3) used on the inner walls and parts of plasma etch tools?
- AThey resist plasma, especially fluorine-based plasma, and erode little, reducing particles and contamination
- BThey conduct electricity well
- CThey make the tool look attractive
Show answer and explanation
Answer: A. They resist plasma, especially fluorine-based plasma, and erode little, reducing particles and contamination
If the chamber walls are eroded by plasma, they become sources of particles and metal contamination, and process conditions drift. Yttrium oxide and similar materials are chemically stable against fluorine-based plasma and erode little, so they are used to coat walls and ring parts.
- A. Correct. They resist plasma and reduce particles and contamination.
- B. Yttrium oxide is an insulating ceramic.
- C. It is not for appearance.