Research and Industrial Application of Key Technologies for PCW 40% Process Cooling Water System

2025-12-24 | Emily

I. Introduction

. Taking the semiconductor manufacturing field as an example, in the production process of chips with advanced processes of 7nm and below, core precision equipment such as lithography machines and etching machines have extremely low tolerance for temperature fluctuations in the working environment. Usually, temperature fluctuations are required to be controlled within ± 0.1 ℃. Small temperature deviations may not only cause dimensional deviations in chip circuit etching, but also affect the uniformity of photoresist coating, ultimately significantly reducing the performance parameters and yield of chips. In the production process of new energy lithium-ion batteries, the electrode material coating process is a key step in determining the energy density and cycle life of the battery. If there is an uneven temperature problem in the cooling system of the coating equipment, it will cause a deviation of ± 5 μ m in the thickness of the electrode coating, resulting in inconsistent internal resistance of the battery. In severe cases, it can cause local overheating risks during the charging and discharging process of the battery pack, reducing the overall efficiency and safety of the battery pack. Therefore, the PCW system must have extremely high temperature stability, efficient heat exchange efficiency, and excellent water quality control capabilities to ensure that various high-end production equipment always operates in the harsh and suitable temperature range.

40% paper-based material is a specialized functional material developed in this study for the core links of heat exchange and water quality filtration in PCW systems. Its comprehensive performance directly affects the operational efficiency, stability, and maintenance costs of the entire PCW system.

. In traditional PCW systems, heat exchange auxiliary materials are often made of metal materials such as aluminum alloys and copper alloys. Although they have high thermal conductivity, they are prone to corrosion by trace impurities in circulating water, have high weight, high processing costs, and low recycling rates; The water quality filtration and sealing materials are mainly made of plastic materials such as polypropylene (PP) and polyvinyl chloride (PVC). Although these materials have strong corrosion resistance, their filtration accuracy is limited, their thermal stability is poor, and they are difficult to naturally degrade, resulting in poor environmental protection. Paper based materials, with their unique fiber interwoven porous structure, exhibit significant potential advantages in terms of thermal conductivity uniformity, pollutant retention ability, and processability customization. At the same time, their raw material sources are relatively wide, and they have certain green and environmentally friendly properties. This study focuses on 40% paper-based materials. By precisely adjusting the ratio of wood pulp fibers to functional components, if the performance bottleneck can be further broken through through process optimization and material modification, it can not only effectively improve the heat exchange efficiency of the PCW system and achieve precise control of equipment temperature, but also use its fine microporous network structure to efficiently filter small impurities, suspended particles, and microorganisms in water, significantly improve the quality of circulating water, reduce the risk of scaling, blockage, and corrosion inside the equipment, thereby extending the service life of the equipment, reducing the frequency and cost of shutdown maintenance, and providing strong technical support for the green and sustainable development of strategic emerging industries such as high-end manufacturing, semiconductors, and new energy.

(II) Research Objectives and Innovation Points

The core of this study focuses on the adaptive application of 40% paper-based materials in PCW systems, aiming to explore the mechanism of the influence of preparation process parameters on the core properties of materials through systematic experimental research and theoretical analysis.

. Specifically, the focus is on clarifying the quantitative correlation between key parameters such as fiber ratio, beating degree, forming pressure, drying temperature, and subsequent modification processes, and core performance indicators such as material corrosion resistance, thermal conductivity efficiency, mechanical strength, porosity, and filtration accuracy. On this basis, a scientific and accurate optimization model for preparation process parameters is established to achieve directional control of 40% paper-based material properties, ensuring that it can perfectly match the operating conditions requirements of the PCW system. At the same time, this study will systematically evaluate the performance stability of materials under complex working conditions such as long-term water immersion and variable temperature and pressure, providing data support for their reliability in industrial applications. In terms of material modification technology innovation, this study breaks through the traditional single modification approach and develops diversified 40% paper-based material modification methods by introducing composite modification methods such as nanoparticles and functional additives, comprehensively improving the comprehensive performance of materials. For example, in response to the problem of bacteria, mold and other microorganisms easily breeding in the circulating water of PCW system, adding nano silver particles or zinc oxide nanoparticles to endow paper-based materials with long-term antibacterial properties, effectively inhibiting the adhesion and reproduction of microorganisms on the material surface, and reducing the risk of biofilm formation; To address the bottleneck of low thermal conductivity efficiency in traditional paper-based materials, high thermal conductivity carbon nanotubes or graphene flakes are introduced. By optimizing the dispersion process to ensure their uniform distribution in the fiber matrix, efficient thermal conductivity pathways are constructed, significantly enhancing the thermal conductivity efficiency of the material and breaking through the application limitations of traditional paper-based materials in the field of heat exchange. At the same time, this study will also achieve deep integration innovation between optimized 40% paper-based materials and PCW systems. Based on the operating characteristics and control requirements of the system, innovative design of material installation structures and adaptation methods will be proposed, and a collaborative optimization system operation control strategy will be proposed to perfectly match material performance with system operation requirements. Ultimately, the dual improvement of overall operating efficiency and stability of PCW systems will be achieved, providing innovative, reliable, and economical technical solutions for high-precision industrial processes.

II. Basic Theory and Technical Framework of PCW System

(1) Core Composition and Working Principle of PCW System

System Composition: PCW systems generally adopt a chilled water cooling water dual circulation architecture, which achieves efficient heat transfer and precise control through two relatively independent and closely coupled circulation circuits, just like the blood circulation system of the human body. Key devices work together to ensure the stable operation of the system.
. Among them, the water tank, as the "reservoir" of the system, not only undertakes the storage function of circulating water, but also has the function of buffering system pressure fluctuations and settling large particle impurities. It is usually made of stainless steel material, and its volume is designed according to the system load, generally 10% -15% of the hourly circulating water volume of the system, providing a solid guarantee for the continuous and stable water supply of the system; The variable frequency pump is the "heart" of the system, and its performance directly determines the accuracy of the system's flow and pressure regulation. By using variable frequency speed regulation technology, the output power can be dynamically adjusted according to the real-time heating load of the production equipment. Taking the PCW system of a 300mm wafer production line in a large semiconductor manufacturing factory as an example, the high-efficiency variable frequency pump equipped with it can achieve a maximum flow rate of 200m ³/h and a head of 50m. It can automatically adjust the frequency to fluctuate between 10-50Hz according to the real-time cooling needs of different equipment such as lithography machines and thin film deposition equipment, achieving a dynamic balance between energy saving and efficient cooling. Compared with fixed frequency pumps, it can reduce energy consumption by more than 25%. Plate heat exchanger is the core component of heat exchange, like an efficient "heat exchanger". It uses 316L stainless steel corrugated plates, which have the advantages of large heat transfer area, high heat transfer efficiency, small volume, and easy disassembly and assembly. Its heat transfer coefficient can reach 1500-3000W/(m ² · K), ensuring fast and efficient heat transfer between chilled water and cooling water. As the "water quality guardian" of the system, the filter adopts a multi-stage filtration method combining a Y-shaped filter and an automatic backwash filter. The Y-shaped filter is mainly used to intercept large particle impurities with a diameter greater than 100 μ m, protecting subsequent precision equipment and pipelines; The automatic backwash filter is responsible for intercepting small particles of 50-100 μ m, and its filtration accuracy can be flexibly adjusted according to needs. It also has a pressure difference automatic triggering backwash function, which does not require manual intervention and effectively avoids filter clogging problems. The control system is the "brain" of the entire PCW system, consisting of PLC (programmable logic controller), HMI (human-machine interface), various sensors and actuators, which can achieve real-time monitoring and precise control of key parameters such as system temperature, pressure, flow rate, conductivity, pH value, etc. Operators can intuitively understand the system's operating status, view historical data, and perform remote operation and parameter adjustment through HMI. At the same time, it has functions such as fault alarm and automatic protection, greatly improving the convenience and reliability of system operation and maintenance.
Operating mechanism: The operation of the PCW system follows the core principles of closed-loop circulation and precise temperature control. The specific operating process is as follows: first, the chiller cools the chilled water to the set temperature of 7 ± 0.2 ℃, and then the chilled water enters one side of the plate heat exchanger flow channel; At the same time, the cooling water flowing out of the production equipment jacket or cooling pipeline absorbs the heat generated by the operation of the equipment, and the temperature rises to 20 ± 0.3 ℃. The cooling water enters the other side channel of the plate heat exchanger. Inside the plate heat exchanger, through the heat conduction of metal plates, following the second law of thermodynamics, heat spontaneously transfers from high-temperature cooling water to low-temperature chilled water, reducing the temperature of the cooling water to the set value of 17 ± 0.3 ℃, completing the cooling process. After cooling, the cooling water is pressurized by a variable frequency pump and then transported back to the cooling pipelines of various production equipment to achieve continuous cooling of the equipment. The chilled water that has absorbed heat returns to the freezer and is cooled again, forming a complete dual circulation loop. This closed loop design ensures that there is almost no material exchange between the circulating water and the external environment, effectively preventing pollutants such as dust and carbon dioxide from entering the water, ensuring long-term stability of water quality, and reducing the loss of water resources. The precise control of pressure and temperature is the key to ensuring the stable operation of the PCW system. In terms of pressure control, the system installs high-precision pressure sensors at key pipeline nodes to monitor system pressure in real time. When the pressure exceeds the set upper limit (such as 0.8MPa), the PLC will automatically reduce the operating frequency of the variable frequency pump, reduce water flow, and thus reduce system pressure; When the pressure is lower than the set lower limit (such as 0.6MPa), increase the frequency of the variable frequency pump, increase the flow rate, and ensure that the system pressure is stable within the range of 0.7 ± 0.05MPa. In terms of temperature regulation, high-precision temperature sensors are installed in the pipelines of the cooling water entering and leaving the plate heat exchanger, as well as at the cooling water outlet of the production equipment. The PLC adjusts the opening of the electric regulating valve on the chilled water side based on the deviation between the cooling water outlet temperature and the set value (17 ± 0.3 ℃) to accurately control the flow of chilled water entering the plate heat exchanger, thereby achieving precise control of the cooling water temperature and ensuring that the production equipment always operates in the optimal temperature environment.

(II) Functional positioning of 40% paper-based materials

Core role: In multiple key links of the PCW system, 40% paper-based materials play various key roles such as filtration and purification, sealing and protection, and heat conduction enhancement due to their unique structural and performance advantages. They are one of the core functional materials that ensure the efficient and stable operation of the system.
Performance requirements: To ensure that 40% paper-based materials can stably adapt to the core working conditions of PCW system at 17 ± 0.3 ℃ water temperature and 0.7MPa pressure for a long time, while meeting the functional requirements of different application scenarios, they must have excellent performance in multiple aspects.

III. Preparation and Performance Analysis of 40% Paper based Materials

(1) Material Formula and Preparation Process

Raw Material Screening: Based on the functional positioning and performance requirements of 40% paper based materials, this study conducted a large number of raw material screening experiments and ultimately determined to use wood pulp fibers (40% mass fraction), polymer resins (30% mass fraction), and functional fillers (30% mass fraction) as the core raw material system. The synergistic effect of each component ensures that the comprehensive performance of the material meets the standard. Among them, wood pulp fibers are used as the skeleton support component of the material, and high-quality coniferous wood pulp imported from Canada is selected. The average length of this type of wood pulp fibers can reach 2.5-3.0mm, with an aspect ratio greater than 80. The fiber surface has abundant hydroxyl groups, which can form good fiber bonding strength through hydrogen bonding, providing excellent mechanical support for paper-based materials. To further enhance the bonding performance of fibers, a systematic pretreatment of wood pulp fibers is required: firstly, the pulp board is dissociated into individual fibers by a hydraulic pulper at room temperature and low speed (300r/min), and 0.1% dispersant is added to prevent fiber aggregation; Subsequently, the PFI pulping machine is used for pulping treatment, with strict control of the pulping degree between 30-35 ° SR. Through fiber refinement and fiber separation, the specific surface area and active sites of the fibers are increased, and the binding force between fibers is optimized. Polymer resin is used as a bonding and modifying component, using independently developed modified polypropylene resin. The resin is modified by grafting acrylic ester groups, with a glass transition temperature as low as -10 ℃ and a fracture elongation of up to 300%. It not only has excellent chemical stability, corrosion resistance, and flexibility, but also forms chemical bonds with hydroxyl groups on the surface of wood pulp fibers, significantly improving the bonding strength between fibers. Functional fillers are selected from surface modified nano silica particles with a particle size controlled between 20-50nm and a specific surface area greater than 200m ²/g. After treatment with silane coupling agents, amino groups are introduced into the surface, which can form a good interfacial bond with wood pulp fibers and polymer resins, effectively filling the pores between fibers and improving the density, hardness, and wear resistance of the material. The specific preparation process of the material is as follows: First, add the pre treated wood pulp fibers to deionized water to prepare a fiber suspension with a mass fraction of 5%. Stir at a high-speed stirrer (800r/min) for 30 minutes to ensure uniform dispersion of the fibers; Step 2: Mix the polymer resin with functional nano silica in proportion, add an appropriate amount of ethanol as the dispersion medium, and prepare a uniform modifier dispersion by combining ultrasonic dispersion (power 500W, time 30min) with mechanical stirring (1500r/min, time 60min); Step three, slowly add the modifier dispersion to the fiber suspension and continue stirring for 120 minutes to ensure that each component fully contacts the reaction; The fourth step is to use a long web paper machine for papermaking, with a controlled speed of 1.5m/min and a vacuum degree of 0.06MPa, to form uniform wet paper sheets; Step 5: Place the wet paper sheet into a hot press machine for hot pressing, strictly control the hot pressing temperature of 150-180 ℃, hot pressing pressure of 5-8MPa, and hot pressing time of 30 minutes, so that the polymer resin melts and tightly binds with the fibers, forming a paper-based material blank with certain strength and structure; Step 6: Perform plasma surface modification treatment on the blank, using argon gas as the plasma gas source, with a treatment power of 300W and a treatment time of 5 minutes. Introduce active groups on the material surface to enhance its surface adhesion and the bonding performance of subsequent functional coatings.
Key process parameters: Through single factor variable experiments and orthogonal experiments, the influence of three key process parameters, fiber beating degree, resin cross-linking degree, and forming pressure, on the properties of 40% paper-based materials was systematically explored, and the optimal control range of each parameter was clarified.