Introduction: Ultrapure Water – The Lifeline of Chip Manufacturing
In semiconductor manufacturing, critical processes such as wafer cleaning, etching, and polishing all rely on ultrapure water. Even minute amounts of impurities (ions or particles)
in the water can cause short circuits or defects in integrated circuits, directly reducing chip yield. Therefore, the purity of ultrapure water is paramount, and every component in
its preparation, storage, and delivery system must meet extremely high cleanliness requirements. In this field, capacitive level sensors, with their superior cleanliness compatibility,
have become the preferred choice for monitoring ultrapure water levels.
The Stringent Requirements of Ultrapure Water Systems for Level Sensors
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Extremely High Cleanliness: The sensor material must be high-grade stainless steel (such as 316L L-VMP), with an electropolished surface (Ra≤0.4μm), free of dead corners,
and free from ion precipitation and contaminant adsorption.
•
High-Temperature Sterilization Resistance: The system requires periodic high-temperature pure steam or hot water sterilization (SIP), and the sensor must be able to withstand temperatures above 120°C.
•
Corrosion Resistance: The sensor must be able to withstand corrosion from highly oxidizing sterilization environments such as ozone water. •
Stable Measurement: Ultrapure water has extremely high resistivity (18.2 MΩ·cm) and a stable dielectric constant, requiring sensors with extremely high signal-to-noise ratio and stability.
Capacitive Level Sensor Solution
1.
Meets the Highest Cleanliness Standards: The sensor's contact parts can use clean materials and processing techniques conforming to SEMI F72 standards, ensuring it will not become a source of contamination.
2.
Perfect Hygienic Connections: Tri-Clamp, ISO, and SMS hygienic process connections are available, ensuring no blind spots.
3.
Tolerant of SIP Processes: Utilizes high-temperature compatible electronic components and sealing materials, stably withstanding sterilization temperatures.
4.
Accurate Measurement: Optimized for the characteristics of ultrapure water, providing stable and highly repeatable level signals.
Core Applications
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Ultrapure Water Storage Tanks: Monitor tank levels and link with water purification equipment (RO/EDI/polishing mixed bed) to maintain water balance.
•
Wafer Cleaner Water Supply System: Provides level control signals to the water tank before the wafer cleaner.
•
High-Purity Chemical Solution Tank: Monitors the level of diluted high-purity chemicals (e.g., SC1, SC2).
Selection Guidelines: The cleanliness level of the sensor (e.g., meeting SEMI standards), wetted material certificates,
internal surface finish certification, and ability to withstand SIP cycles must be clearly specified.
