TSMC introduced the concept of “hot water recirculation” to improve the water heaters for wafer cleaning tools, which effectively reuse non-process hot water.
TSMC developed an industry-leading “recirculation type water heater” for wafer cleaning tools to reuse non-process hot water and successfully reduces waste hot water by 80%.

TSMC Develops Industry-First Recirculation Type Water Heater for Wafer Cleaning Tools, Saving 14M kWh of Electricity

Reducing Waste of Non-Process Hot Water with Simple Improvement of Water Heaters
Jeng-Shin Ma

TSMC fulfills green manufacturing and keeps optimizing power efficiency in the IC manufacturing process. In 2019, TSMC developed an industry-leading “recirculation type water heater” for wafer cleaning tools to reuse the non-process hot water, and successfully reduced waste hot water by 80%. As of November, 29 sets of water heater have been retrofitted with recirculation module, saving a total of 14M kWh of electricity.

The Less Hot Water Wastes, the More Energy Saves

The water heaters continuously supply hot water to the wafer cleaning tools for preventing the stagnant water, which would cause impurity contamination, even though the tools are not in process. In order to reduce energy consumption from the heaters, TSMC’s Operation Technical Board introduced the concept of “hot water recirculation” and cooperated with tool suppliers to develop the recirculation type water heater. A hot water storage tank is installed at the inlet of the heater and the drain of the non-process hot water is re-laid to connect to the tank. Therefore, the non-process hot water can be totally reused.

Hot Water Storage Tank Reuses Non-process Hot Water

Instead of using cold water from the facility pipeline, the recirculated hot water has priority to be supplied into the heating unit in the heater to avoid wasting the non-process heated water. When the hot water in the tank is not sufficient, the cold water will be supplied into the tank from the facility pipeline, mixed with the recycled hot water, and heated for the process. Recirculated hot water pre-heated the cold water, leading to lower power consumption of the heater. Moreover, the good heat insulation minimizes the temperature difference during the recirculation for energy efficiency.

More Fabs Use Improved Water Heaters for Energy Efficiency

Following verification by TSMC’s RD Organization, the improved water heaters are fully applied in Fab 18 and will be promoted to Fab 12, Fab 14 and Fab 15 by the Operation Technical Board in the future. The verification results indicated that 30% of power consumption can be saved with different process conditions. The recirculation type water heaters saved 14M kWh of electricity between January and November in 2019. It is estimated to save 100M kWh before 2025, on track to reach the Company’s sustainable goal of saving 2,800M kWh of electricity in 2025.