Static electricity requirements for clean rooms
(1) Clean room
Semiconductors, flat-panel liquid crystal displays, optoelectronics, and biomedicine all require clean production workshops. Generally, clean rooms refer to rooms or restricted spaces where the concentration of suspended air particles in the space is controlled within specified limits. The smaller the limited number of particles, the higher the cleanliness.
(2) Static electricity in clean room
Due to the cleanliness requirements of the clean room, indoor use
① A large number of decorative materials with high insulation medium, floors, walls, doors, ceilings, partitions, workbenches, chairs, etc., these materials are easy to be electrified and charged by friction, and are not easy to leak and release.
Plastic floor 500V~1000V in photoetching room, 500V~1500V in diffusion room, 500V~1500V in tile floor, 700V for plastic wallpaper, OV~1000V for plastic ceiling, 500V~3000V for metal movable leather chair surface.
②When people wear clean overalls, shoes, walk or work, friction with different materials, equipment and equipment will generate static electricity, and people, clothes, and shoes will be charged.
People wearing nylon clothes and plastic rubber-soled shoes walk slowly on the clean floor, with 7000V~8000V static voltage on their bodies.
1200V (10%~20%RH), 250V (65%~90%RH) can be used for walking on vinyl floor, 35000V (10%~20%RH), 1500V (65%~90) can be used for walking on carpet %RH), the chip assembly line, the work clothes that people wear can reach 10KV.
③The airflow of the air conditioner passes through the primary effect filter, the medium effect filter, and the high efficiency filter, and the purified outlet airflow is electrostatically charged.
Aluminum plate air supply and return air outlets are 500~1000V.
④ A large number of insulating equipment, equipment and tools are also important sources of electrostatic charge. Wafer assembly production line: wafer loading box 35KV, plexiglass cover 8KV, quartz product 1.5KV, wafer tray 6KV, acrylic cover 20KV, table top 10KV, plastic storage cabinet 30KV, glass fiber crystal loading box slides over the polypropylene table top With 10KV.
In short: the higher the cleanliness requirements of the clean room, the more serious the electrostatic charging.