A Study on the Fabrication of a Smart Water Quality Sensor for Semiconductor Cluster Ultra-Pure Water Facilities

Semiconductor manufacturing is a high-precision industry that demands an ultra-clean environment, where the stable and high-quality supply of ultra-pure water (UPW) plays a pivotal role. Within semiconductor clusters, even minor fluctuations in UPW quality can significantly impact product yield and process reliability. As such, real-time and high-precision control of key water quality parameters—including electrical conductivity (EC) is essential. EC serves as a critical indicator of ionic concentration in water and is highly sensitive to temperature. It also exhibits strong correlations with total dissolved solids (TDS) and degas equilibrium quality (DEQ), both of which are important for evaluating the purity and degassing efficiency of UPW. This study presents the design and development of a smart EC-based water quality sensor module, specifically optimized for UPW systems in semiconductor manufacturing facilities. The proposed sensor integrates a high-precision EC measurement cell and a temperature sensor into a compact unit, supported by an embedded microcontroller-based algorithm. This architecture enables real-time output of temperature-compensated EC values, as well as calculated TDS and DEQ metrics, all within a single sensing platform. The performance of the developed sensor was evaluated under various operating conditions, demonstrating superior accuracy, repeatability, response time, and long-term stability when compared to conventional commercial sensors. Additionally, the compact, all-in-one design offers practical advantages in terms of space efficiency and maintenance simplicity. This research provides a practical implementation of a high-reliability, high-sensitivity water quality monitoring solution, and establishes a technical foundation for smart water management infrastructure in next-generation semiconductor fabrication environments.