PPT Slide
CHEN435/PHGN435: Interdisciplinary Silicon Processing Laboratory
Cleaning Silicon Surfaces
Why do you need to clean?
- Reduce contamination - increase yield
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Examples
- Required for device integrity
- Processing step leaves surface in unacceptable state
- Rework - Photolithography screwed up, strip, reclean
Techniques
- Aqueous: FEOL - from fresh silicon to deposition of metals
- Used in 10-20 % of process steps
- Organic Solvents: BEOL - after metal is applied
- Dry or Vapor Phase Cleaning: Reactive gases that attack surface
- Often combined with UV light and/or plasma to increase reactivity