In the semiconductor manufacturing industry, cleanroom consumables, specifically industrial wipes, are critical cleaning tools. Their low ion residue characteristics directly impact chip yield and equipment stability. Uncontrolled ion residue can lead to metal migration, electrochemical corrosion, or device performance drift. Therefore, comprehensive control across the entire chain, from raw material selection and manufacturing processes to packaging design and usage guidelines, is essential to ensure ion release levels meet stringent industry standards.
The choice of substrate for cleanroom industrial wipes is fundamental to controlling ion residue. Semiconductor manufacturing requires industrial wipe substrates with ultra-low dust generation and extremely low ion release rates. Therefore, high-purity polyester fibers or spunlace nonwoven fabrics must be used, and a special degreasing process is employed to remove metal ions and organic impurities from the fibers. Some high-end products utilize 18-megohm ultrapure water for multi-stage cleaning, combined with laser edge sealing technology to reduce edge fiber shedding, minimizing the risk of ion residue at its source.
The formulation design of the solvent system directly affects the ion release characteristics of industrial wipes. The semiconductor industry commonly uses a mixture of isopropanol (IPA) and deionized water, with IPA typically comprising 70%-75%. This ratio effectively dissolves organic contaminants while reducing residue through evaporation. Some manufacturers add chelating agents to form stable compounds by complexing metal ions, further reducing the probability of ion precipitation. The solvent purity must meet electronic-grade standards to avoid introducing impurity ions such as sodium and potassium.
Controlling the cleanliness of the production environment is crucial for ensuring low ion residue. The cutting, impregnation, and packaging of industrial wipes must be completed in a Class 100 cleanroom (ISO Class 5), employing a local laminar flow system throughout to prevent cross-contamination. Production equipment must use corrosion-resistant materials to prevent metal ion precipitation. Some manufacturers introduce ion guns and vacuum adsorption devices to remove electrostatically adsorbed particles in real time during the industrial wipes cutting stage, preventing ion adhesion.
The airtight design of the packaging process is essential for maintaining low ion residue. Industrial wipes typically use a four-layer composite packaging: an inner layer of food-grade aluminum foil to block moisture and oxygen; a middle layer of low-ion-release PE film to prevent impurities from leaching from the packaging material; and an outer layer of anti-static coated cardboard to prevent static electricity from attracting particles during transport. Some products are filled with nitrogen or inert gases to slow solvent evaporation and ion migration, ensuring stable ion concentration before opening.
Strict adherence to usage guidelines is the final line of defense for ensuring low ion residue. Operators must wear cleanroom gloves to avoid contaminating the surface of the industrial wipes with skin oils. Wiping must follow a unidirectional motion principle to prevent secondary contamination of cleaned areas. For sensitive areas such as high-precision lithography machine lenses or the back of wafers, pre-wetting dedicated industrial wipes must be used to reduce ion fluctuations that may be introduced by on-site solvent spraying. Used industrial wipes must be disposed of as medical waste to prevent ions from re-entering the clean environment.
A comprehensive testing system provides quantitative assurance for low ion residue. Manufacturers are required to analyze solvent composition using FTIR (Fourier Transform Infrared Spectroscopy) to ensure the absence of easily residual substances such as silicone oil and amides; and to use IC (Ion Chromatography) to detect the concentration of key ions such as sodium and chloride, requiring that the ion release of a single industrial wipe be less than 0.1 ppm. Some companies will introduce LPC (Liquid Particle Counting) equipment to monitor the number of particles in the solution after wiping with industrial wipes, indirectly assessing the risk of ion residue.
