The concentration of suspended particles in a clean room can be easily reached to a zero level by using a high-performance filter. The actual production site is due to the dust generated by operators, machinery, and peripheral machinery, and the dust generated by parts materials that are contacted during substrate transportation. A small amount of particles were raised on the outside of the manufactured product, causing particle contamination on the clean side of the module.   

How to prevent particulate pollution in a clean room? The following four basic principles should be observed:

　　First, do not bring in   

The method of not carrying particles in a clean room is:

　　1) Before the operator enters the clean room, the machine and parts should be cleaned before being carried into the clean room;

　　2) Those who enter the clean room should wear dust-free clothing, caps, shoes, gloves, masks, etc., which are made of special conductive fibers and do not generate dust or static electricity in the locker room.

　　3) When the air is applied through the air shower room, the particles attached to the clothing surface are removed using high-speed clean air before entering the clean room.

　　4) Before the machine and materials are brought into the clean room, they should be brought into the cleanroom of the clean room in the sealed state. After the maintenance, they shall be wiped with ultra-pure water, and then enter the clean room after being blown by the air shower.

　　5) Wear a closed helmet in the clean room and wear a small fan with a filter on the waist.

　　Second, does not happen

　　While controlling the largest source of pollution--the amount of dust emitted by people in a dust-free room, the second largest source of pollution should be controlled--the amount of dust generated by the manufacturing machine. As the objects move, the friction and contact peeling will cause dust, and the objects will also have particles when they move. Therefore, in order to control the amount of dust generated to a minimum, the following measures should be taken:

　　1) Reduce the action of contact stripping and dust generation;

　　2) Using a material that wears little dust;

　　3) Use a small amount of dust;

　　4) The non-contact working principle of the air compressor applied on the air compressor.

　　Third, no reserve

　　The cleanliness of a clean room can be maintained if the "do not carry" technology is thoroughly implemented. However, it is impossible to have complete cleanliness in the vast clean room because of the frequent access of people and objects and the instigation of manufacturing machines. It is therefore very important that the "no reserve" technique be applied quickly in the filter to remove the microparticles that have occurred. Frequently occurring particles stay on the surface of surrounding objects based on gravity and electrostatic attraction. Sudden vibrations and unstable air flow can cause these accumulated particulates to rise again in the air, increasing the risk of major particulate contamination.

　　In the clean room of the highest grade, from the ceiling to the ground, the air that completely removes the particles must flow vertically downward at a speed of 0.3-0.4 m/s. This is the value calculated by completely exchanging room air and completely filtered air in about 10 seconds. At the same time, the flow of air must also be precisely controlled. In particular, it is necessary to ensure that the flow path of the air flow is unimpeded, because if there are obstacles in the flow path, air vortexes are easily generated to form a stagnant area of air, so that fine particles that have occurred in the vicinity cannot be quickly eliminated and drift in the clean room for a long time. A part of it will adhere to the surface of peripheral equipment and cause pollution.

　　Controlling the air flow prevents the accumulation of particles, but the accumulation of particles on the charged surface cannot be prevented.

In order to prevent adhesion of particles caused by electrostatic adsorption, a conductive material having a degree of electrification of several tens of volts or less is generally used in a clean room. As for the charging of the manufactured product itself, the transfer form and the contact part material with a small degree of charging are used, and the electricity is removed by the static elimination device.

　　Fourth, exclude / remove

　　In a machine that can not avoid the occurrence of a large number of particles, in order not to generate fine particles in a clean room, the operation of external exhaust is directly performed, that is, so-called local exhaust. The countermeasure against the exhaust gas is as follows: Since the introduction of the same amount of external air is necessary, it is accompanied by a large amount of energy consumption. Therefore, it cannot be said that it is an absolute ideal solution. Therefore, as far as possible, while compressing the amount of exhaust gas, it is not only necessary to exhaust the air outside the clean room, but it is also necessary to adopt a countermeasure that the air after removing the particles is returned to the clean room.