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Class

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Class A unit for measuring the cleanliness of a semiconductor clean room.

In the semiconductor industry, the cleanliness of the production line environment is managed using the unit, ‘class’. ‘Class’ is followed by a number which indicates the degree of clean room by a grade. This number usually represents the number of dust particles with a size of 0.5㎛ or larger in a cube measuring one foot (ft) high, wide and deep.

‘Class 10’ means there are less than 10 dust particles of 0.5㎛ or larger per cubic foot (ft3). For example, ‘Class 1’ is comparable to a situation in which a single dust particle about 1/1000 size of the diameter of a human hair exists in a cubic foot (ft) of space.
클래스 10의 의미
클래스 10의 의미