CMP and cleaning
Why is it considered important to transfer wafers to cleaning right after CMP while still wet, without letting them dry?
- ATo keep the wafer's weight
- BTo cool the wafers
- CBecause if slurry particles and chemicals remaining on the surface dry and stick, they become hard to remove in later cleaning
Show answer and explanation
Answer: C. Because if slurry particles and chemicals remaining on the surface dry and stick, they become hard to remove in later cleaning
After polishing, slurry particles and reaction products remain on the surface. If they dry, the particles stick firmly and become hard to remove by cleaning, turning into defects. CMP tools therefore integrate the cleaning section, processing wafers continuously while wet through cleaning and drying.
- A. It is not to keep the weight.
- B. Cooling is not the purpose.
- C. Correct. Dried particles stick and become hard to remove.