CMP and cleaning

Which correctly describes how many times cleaning is performed across the whole LSI manufacturing flow?

  1. AOnly once at the end
  2. BIt is repeated before and after many steps and is one of the most frequent steps in the whole flow
  3. COnly once at the beginning
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Answer: B. It is repeated before and after many steps and is one of the most frequent steps in the whole flow

Cleaning is repeated before and after deposition, etching, ion implantation, CMP and so on, reaching hundreds of times for advanced LSIs. It is among the most numerous steps in the whole flow and a fundamental process supporting yield.

  • A. Cleaning only at the end cannot remove contamination from intermediate steps.
  • B. Correct. It is repeated many times before and after steps.
  • C. A single cleaning cannot remove contamination created in each step.
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More CMP and cleaning questions

  1. Which set correctly lists the kinds of surface contamination removed from wafers by cleaning?
  2. In processes such as multilevel wiring, what is the main reason the wafer surface must be planarized by CMP?
  3. Which correctly describes the basic configuration of a CMP tool?
  4. In Cu interconnect CMP, why is polishing generally divided into stages?
  5. Which correctly describes the general difference between hard and soft CMP polishing pads?