Maintenance of Cleanroom Environment The cleaning operation should be carried out in a cleanroom environment that meets the standards. The cleanliness class of the cleanroom (such as ISO 1 – 9) should match the precision of the electronic components. For example, for high – precision chip manufacturing, a cleanroom of ISO class 1 or 2 may be required to reduce the interference of airborne particles during the cleaning process. During the cleaning, ensure that the air – filtering system of the cleanroom is operating normally, maintaining stable temperature, humidity, and air – flow conditions. Limit the number of people entering the cleanroom. All personnel entering must wear appropriate cleanroom clothing and pass through purifying equipment such as air showers to prevent contaminants such as dust, dander, and microorganisms carried by the human body from entering the cleanroom, which could affect the cleaning effect and the quality of electronic components.
II. Tool Preparation
Selecting Appropriate Cleanroom Swabs Choose suitable swabs according to the size, shape, and cleaning requirements of the electronic components. The material (such as polyester, nylon) and shape (such as pointed – tip, round – tip) of the swab head should be able to adapt to the surface structure of the components. For example, for the tiny pins and gaps on a chip, pointed – tip polyester swabs may be more suitable, enabling precise cleaning of these narrow areas. Ensure that the cleanliness of the swabs meets the requirements. Cleanroom swabs should be thoroughly cleaned and packaged, free from contamination, fiber shedding, etc. Before use, check whether the packaging of the swabs is intact. If it is damaged, the swabs may be contaminated and should not be used.
Selecting Appropriate Cleaning Solvents Choose cleaning solvents that are compatible with the materials of the electronic components and will not cause damage. For metal components, special metal cleaning agents may be used; for components with coatings, select solvents that will not dissolve or damage the coatings. For example, to clean the solder – flux residues on a circuit board, organic solvents such as isopropyl alcohol are commonly used, but pay attention to their concentration and usage amount to avoid over – soaking or corroding the components. Before use, ensure that the purity of the cleaning solvent meets the requirements, and use a clean container to hold the solvent. If the solvent itself contains impurities, it may contaminate the electronic components during the cleaning process.
III. Cleaning Operation Process
Gentle Operation During cleaning, use cleanroom swabs with gentle movements to avoid physical damage to the electronic components. For example, when wiping the surface of a chip, do not press the swab hard to prevent scratching the lithography pattern of the chip or damaging the chip’s pins. For fragile electronic components such as micro – electromechanical system (MEMS) components, extra care is needed as slight external force may cause component damage.
Avoid Over – cleaning Do not over – wipe the same part of the electronic component. Over – cleaning may cause wear of the surface coating, material fatigue, or static – electricity accumulation. For example, frequent wiping of the display screen surface may damage its anti – glare coating, affecting the display effect. The number of wipes and the force applied each time should be moderate, aiming to achieve the cleaning purpose without damaging the component.
Prevent Cross – contamination During the cleaning process, change the cleanroom swabs frequently, especially when cleaning different types of contaminants or different areas of the electronic components. For example, after cleaning an area with oil stains, if the swab is not replaced before cleaning other cleaner areas, the oil stains may be spread to other places. At the same time, when using cleaning solvents, prevent the solvent from flowing between components and causing contamination.
IV. Post – cleaning Treatment
Drying of Components After cleaning, ensure that the electronic components are thoroughly dried. They can be dried with clean nitrogen or left to dry naturally in a low – humidity environment. If there is moisture remaining on the component surface, it may cause problems such as short – circuits and corrosion. For example, for a circuit board, residual moisture may cause the metal traces in the circuit to rust, affecting its electrical performance.
Disposal of Cleaning Tools Used cleanroom swabs and waste cleaning solvents should be properly disposed of in accordance with the regulations of the cleanroom. Generally, these waste materials are considered hazardous waste and should be placed in special containers to avoid secondary pollution to the cleanroom environment. Also, ensure compliance with environmental protection requirements.
HUACHENGYANG