(Process Selection, System Design, and Best Practices)
🔹 Quick Answer
Semiconductor exhaust gas treatment refers to the process of removing acidic gases and VOCs generated during chip manufacturing using a combination of scrubbers, gas concentration systems (e.g., zeolite rotor), and thermal oxidation (RTO).
👉 This combined approach ensures high removal efficiency, energy savings, and stable compliance with strict emission standards.
1. What Gases Are Generated in Semiconductor Manufacturing?
Semiconductor fabrication processes—such as photolithography, etching, cleaning, and deposition—produce complex exhaust gases, including:
- Acidic gases: HF, HCl, HNO₃
- Alkaline gases: NH₃
- Volatile organic compounds (VOCs): IPA, acetone, NMP
- Specialty gases: silane (SiH₄), fluorinated gases
Key Characteristics:
- Multiple emission points
- Large air volume with fluctuating concentration
- Mixed gas composition (acidic + organic)
- Corrosive and potentially toxic
👉 These factors make semiconductor exhaust gas treatment more complex than in most industries.
2. Why Is Semiconductor Exhaust Gas Difficult to Treat?
Semiconductor exhaust gas is difficult to treat because it contains mixed pollutants, fluctuating concentrations, and corrosive components that require multi-stage treatment systems.
Main Challenges:
- Mixed pollutants: Acid gases + VOCs
- Corrosion risk: Requires special materials and pre-treatment
- Process instability: Fluctuating gas concentrations
- High safety requirements: Flammable or toxic gases
- Strict regulations: Tight emission standards
3. What Are the Main Treatment Technologies?
Scrubber (Wet Treatment)
- Best for: Acidic gases
- Strength: Effective and low cost
- Limitation: Ineffective for VOCs
RTO (Regenerative Thermal Oxidizer)
- Best for: Medium to high concentration VOCs
- Strength: ≥99% removal efficiency
- Limitation: Cannot handle acidic gases directly
Zeolite Rotor + RTO
- Best for: Low concentration, high air volume VOCs
- Strength: Energy-efficient and stable
- Limitation: Higher initial cost
Activated Carbon Adsorption
- Best for: Small-scale, low concentration VOCs
- Strength: Low investment
- Limitation: Frequent replacement, safety risks
4. Which Treatment System Is Recommended?
The most widely used solution for semiconductor exhaust gas is:
👉 Scrubber + Zeolite Rotor Concentrator + RTO
Why This Combination Works:
- Scrubber removes acidic gases
- Zeolite rotor concentrates VOCs
- RTO destroys organic pollutants
Typical Operating Conditions:
- Airflow: 10,000 – 100,000 m³/h
- VOC concentration: 100 – 1,500 mg/m³
- Multi-component gas streams
Key Benefits:
- Handles multiple pollutants simultaneously
- High removal efficiency (up to 99%+)
- Reduces energy consumption by 30%+
- Suitable for continuous industrial operation
5. How Do You Choose the Right Process?
| Technology | Best Use Case | Recommended |
| Scrubber | Acid gases | ✅ Essential |
| RTO | Medium/high VOCs | ✅ Recommended |
| Zeolite Rotor | Low concentration VOCs | ⭐ Highly recommended |
| Activated Carbon | Small systems | ⚠ Limited use |
6. Real-World Application Example
Project: Semiconductor manufacturing facility
- Airflow: 50,000 m³/h
- Gas type: Acidic gases + VOCs
- Inlet concentration: ~800 mg/m³
System Design:
Scrubber + Zeolite Rotor + RTO
Results:
- VOC removal efficiency ≥ 98%
- Stable compliance with emission standards
- Reduced energy consumption
7. Frequently Asked Questions
Can RTO treat semiconductor exhaust gas directly?
No.
Acidic gases must be removed first to prevent corrosion.
Why are combined systems necessary?
Because no single technology can handle both acid gases and VOCs effectively.
Is semiconductor exhaust gas treatment expensive?
Yes, but optimized systems (e.g., zeolite concentration) can significantly reduce operating costs.
Can solvents like NMP be recovered?
Yes.
High-concentration solvents can be recovered using condensation or solvent recovery systems.
What is the most energy-efficient solution?
Zeolite rotor + RTO is currently the most energy-efficient approach for large air volumes.
8. Key Takeaway
Semiconductor exhaust gas treatment requires a multi-stage system combining pre-treatment, concentration, and oxidation technologies.
👉 The industry standard solution is:
Scrubber + Zeolite Rotor + RTO
This approach ensures efficiency, safety, and regulatory compliance.
