| 摘要 |
PURPOSE: A pre-monitoring method of a monitoring system is provided to sense previously an abnormal state of a semiconductor cleam room by adding two step pre-alarm points to four step alarm points. CONSTITUTION: The highest alarm point(A1), a high alarm point(W1), a low alarm point(W2), and the lowest alarm point(A2) are set up according to temperature, humidity, wind velocity, pressure difference, density of particles of a clean room. A monitoring system monitors a state of the clean room according to the highest alarm point(A1), the high alarm point(W1), the low alarm point(W2), and the lowest alarm point(A2). Pre-alarm points(U1,U2) having sensitivity of 200 or more percents are set up between the high alarm point(W1) and the low alarm point(W2) in order to add a pre-alarm function to the monitoring system.
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