Complete collection of uses of dust-free cloth: 5 major selection techniques to improve cleaning efficiency of clean rooms

The core tool for clean room cleaning: Analysis of the key role of dust-free cloth

As the core consumables of a clean room environment, dust-free cloth assumes the key responsibility of maintaining the cleanliness of the production environment. Its main application scenarios include surface cleaning of precision instruments, wall maintenance of clean room, and wiping of automated equipment. According to the ISO 14644 standard of the International Organization for Standardization, in a clean room of 100 to 100-level clean rooms, dust-free cloth can effectively remove particulate pollutants of more than 0.5 μm, especially for micron-level pollutants such as silicon chips and photoresist residues produced in semiconductor manufacturing, which can reach 99.6%. This special fabric has become the core consumable to ensure the yield rate of high-end manufacturing fields such as microelectronics and biomedicine through the dual mechanisms of physical adsorption and electrostatic control.

Five technical elements for choosing dust-free cloths In the clean room consumable selection system, the following technical parameters need to be evaluated:

1. The selection of basic material characteristics directly affects the cleaning efficiency and service life. Taking polyester fiber as an example, its monofilament diameter is controlled within 5μm, and combined with gamma radiation sterilization technology, it can meet the biosafety requirements of the production environment of medical devices. Test data from the ASTM F2100 of the American Materials Testing Association shows that high-quality polyester dust-free cloth can maintain more than 90% cleaning efficiency after 500 cycles.

2. The innovative application of microfiber fibers is made of 80% modified polyester and 20% polyamide. The fiber diameter is only 0.13dtex (about 1/100 of the human hair diameter). This microstructure forms an adsorption effect similar to a magnet, which has a significant capture effect on the ITO conductive layer debris in liquid crystal panel manufacturing. A test report from the Japan Electronics Industry Association JEITA shows that in a level 100-level clean room environment, the microfiber dust-free cloth has a 3.2-fold retention capacity of 0.3μm particles than that of traditional materials.

3. The upgrade and iteration of the weaving process uses a scroll-type dust-free cloth with straight-grain weaving technology, with a warp and weft density of up to 200×180 rods/inch². This precision structure is particularly suitable for isopropanol wiping in the COG process of the LCD industry, which can remove fingerprint oil stains while ensuring that there is no fiber residue on the substrate surface. Experimental data from the Fraunhofer Institute in Germany showed that this type of dust-free cloth can maintain a stable low dust release of 0.08 mg/cm³ during continuous operation.

4. The difference between laser edge sealing and ultrasonic edge sealing technology significantly affects material performance. The former melts fibers at instantaneous high temperature to form a sealing belt with a width of only 0.2mm, which is suitable for cleaning hydraulic systems in the aerospace field. The latter uses high-frequency vibration to achieve molecular-level bonding, which is particularly suitable for ultra-high-precision scenarios such as optical lens cleaning.

5. The electrostatic control indicators are according to the IEC 61340-5-1 standard, and the surface resistance of Class A anti-static dust-free cloth must be controlled at 10^6-10^9Ω. In the microelectronic packaging process, this feature can effectively prevent CMOS devices from being electrostatically damaged. Samsung Electronics Technology White Paper shows that the use of dust-free cloth with composite conductive fibers can reduce the ESD accident rate by 72%. Analysis and application guide for anti-static dust-free cloth

6. The core value of anti-static performance. Anti-static dust-free cloth is specially used in precision manufacturing environments that are sensitive to static electricity. Its unique conductive fiber braided structure can continuously maintain a surface resistance value of <10^6Ω. The 100% continuous polyester substrate used by the Colinwei brand is combined with the embedded conductive wire process and has passed the ASTM D257 standard to achieve stable electrostatic dissipation function. In scenarios such as semiconductor wafer cleaning and LCD panel maintenance, this material can not only effectively prevent ESD damage, but also has the ability to retention of 0.3μm-level particles. Combined with the water absorption index of 3.2g/100cm², it significantly improves the surface cleaning efficiency of electronic components.

7. Cleanliness control of edge sealing process. The cutting process in dust-free cloth production will produce micron-scale fiber chips, so edge sealing processing becomes a key node in cleanliness control. Taking polyester substrate as an example, different edge sealing methods can cause 2-3 levels of difference in ISO 14644-1 cleanliness level:

8. Laser welding technology instantly generates a high temperature of 200-300℃ through 1070nm wavelength laser to achieve fiber fusion. The 0.2mm welded tape formed by this process has an IP5X dustproof grade and is suitable for microelectronic packaging processes. It is recommended to cooperate with ultrasonic cleaning pretreatment to maintain a level 100-level clean environment.

9. Ultrasonic pressing process 27kHz high-frequency vibration combined with precision cutting tools to achieve material recombination at the molecular level. This technology is particularly suitable for the assembly process of medical equipment, with an edge strength of 18N/cm², which can avoid secondary contamination when cleaning precision components such as CMOS sensors.

10. The hot melt setting scheme uses a PID temperature control system to stabilize the blade edge at the polyester glass transition temperature (about 80℃) to achieve continuous processing of the coil. In the OLED screen bonding process, this edge sealing method can ensure a thickness tolerance of 0.05mm, meeting the flatness requirements for touch module installation.

11. The engineering recommendation for specification selection is based on the ergonomic design of 9"×9" specification (expanded area 810cm²) and is folded in four equal parts, perfectly adapted to the operator's palm shape, and the cleaning efficiency is 30% higher than the standard size. For large-area operations such as photovoltaic panel cleaning, the 12"×12" specification combined with the robotic arm system can achieve a surface coverage of 98%. It is worth noting that the medical industry recommends the use of 7"×7" special-shaped cutting scheme to facilitate access to the narrow cavity of CT equipment for maintenance.

12. Cleanliness hierarchical management system According to ISO 14644-1 standard, the particle release amount of dust-free cloth must match the clean room level. Taking Class 10 (≤3520 0.1μm particles per cubic meter) environment as an example, an ultra-clean dust-free cloth that has been treated with hydrogen peroxide vapor phase must be selected. In the field of biopharmaceuticals, it is recommended to use gamma-ray sterilized medical grade products, with the total number of microorganisms controlled at <10CFU/g to meet the requirements of GMP specifications. For specific selection, please refer to the wiping material performance evaluation system in the ASTM E2311 standard, and combine it with FTIR spectral analysis to ensure material compatibility.

13. Standardized operating procedures and technical points of dust-free cloth In a clean room environment, the correct use of dust-free cloth directly affects the cleaning efficiency and pollution control effect. According to the requirements of ISO 14644 standard, operators should adopt a systematic folding method, combining the synergy between physical wiping and chemical treatment to achieve effective removal of particulate pollutants. Laboratory data shows that standardized operations can increase the removal rate of particles with particle size ≥0.5μm to more than 90%.

Analysis of standardized operation steps: 1. During the preparation stage, the operator should always wear clean gloves and check the density of the dust-free cloth fiber (recommended to be more than 200 pieces per square centimeter). The dust-free cloth is spread out in the air, and the contactless folding method is adopted: first fold in half to form the initial working surface, and then fold in half to form four independent cleaning areas. This "four-layer protective structure" can effectively avoid cross-contamination, similar to the sterile treatment process of surgical instruments.

Dynamic wipe technology adopts a one-way linear wipe mode, and adjacent wipe trajectories maintain 30% overlapping coverage. When advancing from the clean area to the contaminated area, the wipe cloth must be kept at a 45° contact angle with the surface and applied a uniform pressure of 200-300 grams. In the semiconductor manufacturing workshop case, this method can control the residual amount of surface particles below 5 per square centimeter.

Multi-faceted Utilization Strategy Each cleansing surface is limited to a single straight wipe, and the new working surface is enabled after flip. Through four folds, 16 independent cleaning units can be formed, greatly improving material utilization. A certain optoelectronics company has shown that standardized operations can increase the efficiency of dust-free cloth use by 40%, while reducing the risk of fiber shedding.

Pollution control points When the contact surface reaches the usage limit, it should be sealed and treated immediately according to medical-grade waste standards. For special scenarios such as biosafety laboratories, it is recommended to pre-disinfect with 70% isopropanol solution. Important tip: It is absolutely forbidden to repeatedly unfold the contaminated wipe surface. This operation will cause the secondary pollution index to rise by 2-3 orders of magnitude.

After the system cleaning verification is completed, the surface cleanliness verification needs to be performed using a laser particle counter. According to the requirements of the US FDA guidelines, the residual particles in the A-level clean areas of the pharmaceutical industry should be ≤3.5 per cubic meter. For the surface of key equipment, it is recommended to use ATP biofluorescence method to detect microbial contamination.

This specification has been successfully applied to wafer manufacturing, precision optical component production and other fields.

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