摘要 |
The present invention disclosed herein is an apparatus for drying a substrate. In accordance with the present invention, the apparatus includes a measuring unit to detect a density of IPA vapor at predetermined regions in a process chamber or a pipe. The measuring unit has a radiating unit, a detection unit, and a window unit. The radiating unit transmits infrared-ray in a wavenumber region where light is absorbed by the IPA vapor.
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