The clean room is a special enclosed building built to control the number of particles in the indoor air and has the following characteristics: a. The number of particles in the air is less than a certain number b. It can prevent the entry of external dust particles c. Can quickly exhaust the fine dust particles and harmful gases generated in the room to the outdoors d. Maintain temperature, humidity and room pressure at a certain standard e. It can prevent harmful process interference such as static electricity and electromagnetic