CMP and cleaning
What is a point of caution for batch cleaning, in which many wafers are immersed in the same tank of cleaning solution?
- AContamination released or shed from one wafer may transfer to other wafers through the liquid (cross-contamination)
- BOnly one wafer can be processed at a time
- CNo chemicals are used at all
Show answer and explanation
Answer: A. Contamination released or shed from one wafer may transfer to other wafers through the liquid (cross-contamination)
Batch cleaning processes many wafers in the same tank, giving high throughput, but contamination from one wafer can spread through the liquid and deposit on others. Managing liquid replacement, circulation and filtration is therefore important, and single-wafer tools are also used for contamination-sensitive steps.
- A. Correct. Cross-contamination through the liquid needs care.
- B. Batch cleaning processes many wafers at once.
- C. Batch cleaning also uses chemicals.