| 摘要 |
PURPOSE:To improve cleanness and increase the probability of obtaining acceptable products by maintaining at reduced pressure a clean room for accomodating a group of apparatuses for manufacturing semiconductor integrated circuits. CONSTITUTION:A clean room is kept at a low pressure or extra-low pressure by a vacuum pump 2. Dust floating in the atmosphere of a clean room is considered to be staying for a long time by Brawnian movement of gas molecule in the air and, in general, the smaller the dust particles, the longer they are staying in the air. However, under low or extra-low pressure, Brawnian movement becomes inactive and more dust particles are deposited on the floor, while under the normal temperature and the normal pressure they will not fall. Especially under the extra-low pressure, no matter how small the dust particles are, as long as they have masses, they can fall.
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