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Water-Solid Synergy and Closed-Loop Resource Recycling

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UltraPure Water System Process for the Semiconductor Industry | Water Healer

UltraPure Water System for the Semiconductor Industry (WH-UPW)

Process Overview

Semiconductor manufacturing is one of the most demanding industrial scenarios for water quality. Core processes such as wafer cleaning, etching, lithography, chemical dilution and equipment cooling all consume large volumes of UltraPure Water (UPW). Even trace ions, particles, TOC, dissolved gases, bacteria and metal impurities in the water directly cause wafer yield loss, circuit short-circuits and device performance drift. The UltraPure Water system for the semiconductor industry is a complete water treatment process that purifies raw water (municipal tap water/reclaimed water) through multiple purification stages to produce UPW meeting the different process grades of a semiconductor fab, while providing continuous water-quality monitoring, circulating delivery and reuse.

Industry Benchmarks (Mainstream UPW Product Water Specifications for 12-inch Wafer Fabs)

18.2 MΩ·cm Resistivity (25°C) — theoretical limit

< 0.5–1 μg/L Total Organic Carbon (TOC)

< 1 pcs/mL Particles (≥ 0.05 μm)

< 0.5–1 μg/L Dissolved Oxygen (DO)

< 0.05–0.1 μg/L Total Silica

ppt level Metal ions (Na, K, Fe, Cu, etc.)

System Features

Extreme Impurity Control

Control is tightened from the ppm level down to the ppt (ng/L) level, with high sensitivity to trace metals and sub-micron particles

Dedicated Polymer Materials

Water-contact components use Clean-PVC, SS316L-EP, PVDF and PFA to avoid metal and TOC leaching and reduce secondary contamination

Continuous Online Monitoring

24 h non-stop water-quality monitoring with automatic alarms and interlocks on any excursion

High Reliability Requirements

Semiconductor lines cannot tolerate a water interruption, so the system is normally equipped with standby equipment, dual power supply and an emergency water tank

Water-Saving Recycling and Reuse

Wafer fabs consume huge volumes of water, and process wastewater recovery is standard equipment in modern semiconductor fabs

Process Principle

A semiconductor UPW system is typically divided into four modules — the pretreatment section, the primary RO desalination section, the EDI + polishing mixed bed finishing section, and the UPW circulation, delivery and reuse section — removing impurities from the water stage by stage:

Module 1: Pretreatment System

Composed of a multi-media filter (MMF), an activated carbon filter (ACF), ultrafiltration and a precision security filter.
Its purpose is to protect the downstream reverse osmosis membranes by removing suspended solids, colloids, residual chlorine, organics and hardness from the raw water.

Module 2: Reverse Osmosis (RO) Desalination Section

A first-pass/second-pass reverse osmosis configuration removes the vast majority of ions, colloids and macromolecular organics from the water, serving as the primary desalination unit for UPW.

Module 3: Finishing Unit

RO permeate enters EDI (continuous electrodeionization) and then the polishing mixed bed for deep ion removal, raising the resistivity to 18.2 MΩ·cm.
EDI: continuous ion removal, with no acid or caustic regeneration required;
Polishing mixed bed: terminal ion polishing with mixed cation and anion resins, the final barrier against ionic impurities and the signature unit of a semiconductor UPW system;
Auxiliary units: UV oxidation (TOC degradation), degassing membrane (DO removal) and terminal ultrafiltration (particle and bacteria retention).

Module 4: UPW Recirculation and Reuse

UPW is delivered through a closed circulation loop of "tank + circulation pump + piping", so the water never stagnates or degrades.
The circulation loop is equipped with online instruments — resistivity, TOC, dissolved oxygen (DO), particle counter, pH, silica and metal ions — for full-parameter, real-time water-quality assurance.

Ultrapure Water Production Process （Mainstream Process）

Dedicated Biological Treatment Technology for TMAH Wastewater | Water Healer

Case Applications

An Integrated Circuit Company in Shaoxing — Pure and Wastewater Engineering for the Next-Generation Heterogeneous Integration Packaging Technology (DDIC) Project

Treatment process: Organic wastewater is treated by anoxic + aerobic + MBR to meet discharge standards: TMAH waste liquor is pretreated and then fed into the organic system; acid-alkaline wastewater is neutralized and discharged; grinding wastewater is reused via UF+ACF+RO. Semiconductor UPW system (pure water is prepared via EDI + polishing mixed bed + precision filtration)
Effluent standards: pH 6–9, COD < 400 mg/L, BOD₅ < 200 mg/L, SS < 100 mg/L, etc.
Pure water quality specifications: resistivity ≥ 18.0 MΩ·cm, water temperature 21±2°C, TOC < 20 ppb, dissolved SiO₂ < 10 ppb
Process advantages: separate collection and treatment by stream, with dedicated pretreatment of TMAH waste liquor ensuring biochemical stability; grinding wastewater reuse; strong shock-load resistance, stable water quality, water saving and consumption reduction, and convenient operation and maintenance (O&M)