15 Ton per Hour Semiconductor Ultrapure Water System in China
This project is a core utility project supporting a newly built semiconductor wafer factory. The enterprise focuses on the R & D and production of advanced process wafers. Key processes such as wafer cleaning, etching, and photolithography have zero tolerance for trace ions, organic matter, and particles in water. Impurities will directly lead to wafer defects and a sharp drop in yield.
Project Challenges：
1. The content of weak electrolytes such as silicon and boron and microorganisms in the raw water is relatively high, so the pretreatment needs to remove them accurately.
2. The space for equipment is not abundant, so it is necessary to ensure the compliant design of the equipment while considering the space layout.
3. It is necessary to strictly control the initial investment cost and later operation and maintenance costs, require low energy consumption, and reduce the pressure of environmental compliance.
Process Flow：
- Pretreatment Unit: It adopts a multi-media filter to remove suspended solids and turbidity in water, an activated carbon filter to adsorb residual chlorine and organic pollutants, a water softener to reduce the hardness of incoming water and prevent scaling risks, and a 5-micron precision filter for terminal pretreatment. This unit can extend the service life of core components.
- Reverse Osmosis Unit: A process of double-stage reverse osmosis + EDI configuration + UV sterilization + terminal microfiltration filter is adopted to remove more than 99% of ions and organic matter, and the produced water resistivity can reach more than 15 MΩ·cm. UV sterilization can ensure that the microbial indicators meet the standard, and terminal filtration ensures that there is no particle residue in the produced water.
- Polishing Mixed Bed: A polishing mixed bed is added after the EDI to further deeply remove residual trace ions, colloids, and other impurities in the water, ensuring that the produced water resistivity stably reaches 18.2 MΩ·cm, which fully meets the extreme requirements of the production line for ultra – pure water.
Project Effects：
- Stable Discharge Compliance: Water quality compliance: The effluent indicators fully meet the semiconductor process requirements, and the wafer defect rate is controlled below 0.5%.
- Controllable Operation and Maintenance Costs: The system has a high degree of automation, requiring only simple daily inspections. The pretreatment unit effectively extends the service life of the reverse osmosis membrane, and the average annual operation and maintenance cost per set is 55% lower than that of peers; At the same time, the easy-to-operate design helps the operation and maintenance team of the new factory quickly master the system management ability.
- Reasonable System Design and Application: The system is designed with pipeline routes that fit the space layout according to the size and direction of the equipment room, saving space occupation.