ozone water

Ozone water combines DI water with dissolved ozone gas for environmentally friendly cleaning and oxidation. **Ozone source**: Generated on-site from oxygen using corona discharge or UV. 20-100+ ppm concentrations in water. **Mechanism**: Ozone (O3) is powerful oxidizer. Breaks down organics, oxidizes metals, grows thin chemical oxide on silicon. **Advantages**: Replaces some aggressive chemistries (piranha, SC1), environmentally benign (decomposes to O2), no chemical waste, lower cost. **Applications**: Photoresist stripping, organic cleaning, surface oxidation, pre-clean step. **Combinations**: Ozone + HF alternating treatments increasingly popular for particle removal. Ozone + megasonic. **Limitations**: Lower oxidizing power than piranha for thick photoresist. May need multiple steps. **Process variations**: Spray, immersion, or vapor phase ozone delivery. **Decay**: Ozone decomposes rapidly - must use near generation point. Short half-life in water. **Equipment**: Ozone generators, contactors for dissolution, POU delivery, ozone destruct systems for exhaust. **Trend**: Growing adoption as fabs pursue cleaner, safer chemistries.