With the goal of implementing its Environmental Policy, TSMC is dedicated to developing the best feasible technologies to minimize air pollutant emissions. The nitrogen oxide (NO_x) reduction program done in collaboration with suppliers, has improved VOC exhaust abatement equipment to reduce nitrogen oxide emissions by 65%. TSMC has further upgraded thermal type, burner type and plasma type local scrubbers, using the redox reaction method, uniform combustion temperature control, and the multi-stage heating method to reduce NO_x. Tests result shows 60% reduction in NO_x emissions in a single fab. By November 2024, these NO_x reduction methods have been implemented in Fab 12B, 14A, 15A, and 18B, and included as a standardized design in new fabs to enhancing air emission treatment ability.

Develop NO_x Reduction Methods to Enhance Equipment's Green Performance

The wafer manufacturing process generates various exhaust gases that require local scrubbers with combustion temperatures between 700°C to above 2,000°C for decomposition, based on their characteristics. At these high temperatures, nitrogen reacts with oxygen to form thermal NO_x. To improve air quality, TSMC studies the heating method and nitrogen oxide formation mechanisms of different local scrubbers, and developed NO_x reduction methods with suppliers. For thermal type local scrubbers, the redox reaction method uses CH₄ as a reducing agent to convert NO into N₂ and CO₂ to reduce NO_x. For burner type local scrubbers, the uniform combustion temperature control method uses N₂ as a carrier gas to increase temperature uniformity in reaction chamber to reduce areas with excess heat and raise the temperature in the cold zone, as well as control the natural gas to oxygen ratio for a more uniform temperature to optime efficiency. For plasma type local scrubbers, the multi-stage heating method preheats the process exhaust gases to lower the required combustion temperature and reduce NO_x production.

In response to the United Nations Sustainable Development Goal (SDG) 13—Climate Action, TSMC has launched a NO_x reduction program to reduce air pollution caused by byproducts from local scrubbers. The Company is continuously developing NO_x reduction technologies for various local scrubbers. Additionally, TSMC strengthens internal control standards in accordance with current regulations, expands its air pollution reduction efforts, and advances towards the goal of Net Zero Emissions.