| 摘要 |
PURPOSE:To easily know the adequate timing for exchanging a treating liquid by detecting the change rate of the absorbancy of the treating liquid per unit time and making decision as to whether the treating liquid is deteriorated or not in accordance with the change rate. CONSTITUTION:The treating liquid of the resist stripping liquid in a storage tank 1 for the treating liquid is sent into a photocell 5 by a route 2. The treating liquid is irradiated with rays of a specified wavelength and the absorbancy of the treating liquid is measured. This measurement is executed twice at a specified time interval while the treating liquid makes treatment such as resist stripping. The results thereof are sent to a data processor M. The processer M measures the change rate of the absorbancy per unit time in accordance with the results of the measurement and displays that the treating liquid is deteriorated if the calculated result is larger than a preset constant. The adequate timing for exchanging the treating liquid is easily known in this way. |
