High-Frequency Technology is a supplier of ultrapure water systems focused on core electronics industries such as chip manufacturing. Its services cover every stage of ultrapure water—from preparation and storage/transportation to collection, treatment, and reuse—ensuring that downstream customers’ production processes have an uninterrupted supply of ultrapure water throughout all stages.
Providing customers with first-class ultrapure water and recycling solutions and equipment.
Semiconductor ultrapure water has extremely high specification requirements.
The process of pure water preparation systems is highly complex.
Involves multiple specialized disciplines:
Physics, chemistry, photochemistry, mechanics, aerodynamics, fluid dynamics, and more.
Using multiple process technologies:
Multi-media filtration, activated carbon adsorption, ion exchange, reverse osmosis membranes, ultraviolet disinfection, ultraviolet TOC removal, electrodialysis, ultrafiltration, nanofiltration, vacuum degassing towers, membrane degassing, and more.
The company specializes in ultrapure water technology and has assembled a seasoned technical team. Through continuous R&D investment and process exploration, the company’s ultrapure water systems can produce ultrapure water with purity levels reaching ppt grade—containing ion concentrations as low as one part per trillion. The company is one of the few domestic enterprises capable of providing ultrapure water systems for the semiconductor chip industry, and it is also the only domestic supplier equipped with the capability to produce ultrapure water for 12-inch 14nm chip manufacturing lines.
The preparation of ultrapure water is a process that removes nearly all impurities from water. Common impurities found in water include particulate matter, electrolytes, organic compounds, microorganisms, and dissolved gases. The preparation of ultrapure water involves multiple treatment stages, ultimately purifying municipal water supplies to meet the stringent standards required for chip manufacturing. Generally speaking, an ultrapure water preparation system can be further subdivided into three sub-systems: pretreatment, primary treatment, and polishing.
A Preprocessing System
The pretreatment system is the first-stage water treatment system designed based on the customer’s raw water quality and system scale. Its primary function is to remove particulate matter larger than 5 nm from the water, including oxides, organic compounds, and primary ions, as well as to soften water hardness. This helps reduce the load on subsequent treatment units, ensuring stable and efficient operation of the entire water treatment system. Typical pretreatment systems primarily employ processes such as filtration, ion exchange, UV irradiation, and reverse osmosis; specific details are provided below:
| Processing technology |
Technical highlights |
| Filtering |
The pretreatment system removes particulates, oxides, and certain organic substances using equipment such as multi-media filters (MMF) and activated carbon filters (ACF). The operation of the multi-media filter is guided by readings from a sludge density index (SDI) meter, while the activated carbon filter operates based on parameters detected by a residual chlorine meter. The selection of filter media specifications, the appropriate dosage, and the control of filtration rate are all critical factors in achieving optimal filtration performance. |
| Ion exchange |
In the pretreatment stage, ion exchange is typically carried out using a cation-exchange bed—carbon dioxide degasser—anion-exchange bed (2B3T) configuration. This setup serves as the first-stage desalination unit in the pretreatment phase. Incoming water flows through a series of pressure vessels packed with both cation- and anion-exchange resins, thereby replacing most of the ions present in the tap water with ions bound to the resin matrix. Once the ion-exchange resins become exhausted, they are regenerated using acid and alkali solutions to restore their exchange capacity, ensuring continuous system operation. The carbon dioxide degasser’s function is to remove hydrogen ions (H⁺) generated during the operation of the cation-exchange bed. + ) and carbonate ions (CO₃²⁻) in water 3 2- ) and bicarbonate ions (HCO₃⁻) 3- ) The carbon dioxide (CO₂) produced by the reaction 2 ) gases, thereby reducing the load on the anion-exchange bed and ensuring stable, continuous effluent quality. The key to ion exchange lies in selecting the appropriate bed configuration and operating time based on the distribution characteristics of cations and anions in the raw water, thus striking a balance between operational efficiency and running costs. |
| UV irradiation |
UV irradiation is primarily carried out using a 254nm ultraviolet light source. Leveraging the property of ultraviolet light to inhibit bacterial growth, this process eliminates various microorganisms in water that could otherwise affect the performance of downstream equipment, thereby further safeguarding these downstream units against potential microbial contamination risks. The key to effective UV irradiation lies in adjusting the intensity and exposure time of the ultraviolet light based on specific water quality parameters. |
| Reverse osmosis |
Reverse osmosis is a system composed of reverse-osmosis membranes, pressure vessels, pipelines, instruments, and other components assembled according to specific design principles. Its fundamental principle is based on the selective permeability of membranes: under pressure, ions and water molecules in the feed water are separated on either side of the membrane, thereby concentrating ions on the concentrate side of the membrane and further removing ions on the freshwater side. Reverse-osmosis technology significantly extends the service life of subsequent deionization equipment and substantially reduces the consumption of chemicals. |
B Primary Treatment System
The function of the primary treatment system is to further improve water quality before it enters the final polishing stage, ensuring that indicators such as organic matter, particulate matter, and specific solutes in the water meet or closely approach the quality requirements for final ultrapure water. The processes employed in the primary treatment system primarily include UV irradiation, mixed-bed ion exchange, and membrane degassing. After undergoing primary treatment, the water quality can already achieve a high level of purity. The specific details of each step in the primary treatment process are as follows:
| Processing technology |
Technical highlights |
| UV irradiation |
In primary treatment systems, the primary purpose of UV irradiation is to remove total organic carbon (TOC). TOC removal via UV irradiation involves using ultraviolet energy at 185 nm and hydroxyl radicals (-OH) generated from the photolysis of water molecules to break down organic compounds into carbon dioxide and water molecules, thereby effectively removing organic matter from the water. The key to successful UV irradiation lies in taking into account specific water quality parameters and precisely controlling the intensity of the UV light and the exposure time. |
| Mixed-bed ion
Exchange |
In primary treatment systems, ion exchange is primarily achieved through mixed-bed units. A mixed bed is a pressure vessel filled with both cation and anion resins. Its main function is to further remove ions from the water by exchanging them with H⁺ ions bound to the resin’s functional groups, utilizing the cation and anion resins’ exchange capabilities. + And OH - A displacement occurs, thereby adsorbing the cations and anions onto the resin, and the displaced H⁺... + And OH - Combine into H 2 O, further purify the deionized water to obtain even higher purity; at this stage, the water quality typically reaches above 18 megohms. After the resin has lost its effectiveness, its exchange capacity can be restored through regeneration steps involving acids and bases. |
| Membrane degassing |
A deoxygenation membrane is a membrane with special pores; the characteristics of its surface allow gas molecules (O₂) in water to pass through. 2 ) Water molecules can pass through the membrane, while oxygen molecules cannot, thereby achieving the separation of oxygen from water. By adjusting different levels of vacuum and using sweep gases of varying purity, it is possible to leverage Henry’s Law and Dalton’s Law from physics to achieve different concentrations of trace dissolved oxygen. |
C Polishing system
The polishing system for ultrapure water is positioned at the end of the ultrapure water production process. Through additional UV irradiation, mixed-bed ion exchange, membrane degassing, and precision filtration, this system further enhances water quality. The polishing system relies on high-quality polishing resins with even higher processing accuracy and purity levels, as well as high-performance separation membranes, to achieve refined water purification and ultimately attain stable temperature, stable pressure, and consistent water quality. Moreover, due to the highly reactive nature of ultrapure water, it cannot be stored statically. Therefore, the ultrapure water generated in the polishing system must be continuously circulated and purified to maintain its purity until it is drawn off at the point of use. The specific treatment processes employed by the polishing system are as follows:
| Processing technology |
Technical highlights |
| Polishing
UV irradiation |
The device operates on the same principle as the TOC UV unit used in the deionization stage of water production, further reducing the TOC content in ultrapure water to meet the target of 0.5 ppb. |
| Polished mixed bed
Ion exchange |
Using disposable ion-exchange resins and carefully selecting and controlling the flow rate, we perform final ion removal on the upstream water. Depending on the specific water quality requirements of the user, we choose different types of resins to meet stringent control targets—including those for resistivity as well as weak acid ions such as silica and boron ions. |
| Polishing
Membrane degassing |
The functions and principles are the same as those of the devices in the primary treatment system; when used at the end point, they are designed to meet the most stringent requirements for dissolved oxygen levels in ultrapure water. |
| Terminal
Ultrafiltration |
Specially manufactured ultrafiltration membranes are designed to remove particles with a molecular weight cutoff greater than 4,000 Daltons, thereby ensuring that the particle levels in the final ultrapure water meet stringent specifications. |
