Reclaim Strategies for Semiconductor UPW White Paper

This white paper explores the challenges involved with reclaim strategies for semiconductor UPW (ultrapure water) within the microelectronics industry. Modern semiconductor fabs are completely dependent upon a continuous flow of UPW for normal operations. These fabs measure their water usage in thousands of cubic meters per day. The cost of producing this water, both in capital expenditures and in discharge costs, is continually rising as worldwide fab capacity and technology is expanded and improved. New requirements to increase the volume of reused UPW and to reduce contamination levels in waste emphasize the importance of constant monitoring and measurement of conductivity, total organic carbon (TOC), temperature, pH, and dissolved oxygen (DO).

The solution to these technical challenges is to reprocess the water to allow either UPW recycling within the same processes or to reuse UPW in another process within the facility. Reclaim strategies for semiconductor UPW can provide multiple benefits, including reduced costs and ensured compliance with environmental guidelines. These strategies provide a positive return on investment. UPW – also commonly referred to as DI water within this industry – is expensive to produce, and recycling UPW from the waste stream costs less per liter than initial purification steps. In terms of environmental performance, UPW reuse and other green engineering technologies promote sustainability for the industry. Having a water recycling strategy demonstrates an awareness of the importance of water to the local community, and can therefore bolster those relationships.

In UPW reclaim processes, measurement and control of conductivity, temperature, pH, and dissolved oxygen (DO) alone will not provide the complete analytical information required to accurately control the system. Particularly, real-time TOC analysis is essential for fab managers to fully understand and control the entire water purification process.

The 6000TOCi sensor by METTLER TOLEDO enables rapid, continuous measurement to ensure that excursions are never missed. This high-performance total organic carbon sensor supports stable and reliable analysis for repeatable and precise measurements. Verifiable system performance and advanced system diagnostics ensure effective TOC measurement. Finally, with an optimized flow rate of only 8.5 mL/min, the 6000TOCi is an extremely water-efficient sensor that minimizes the use of expensive, high quality water.

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