| 摘要 |
<p>PURPOSE:To easily measure the water content in an etching solution by using the etching solution just after regulation as a reference solution and an actual etching solution as a measured sample solution, and determining a differential transmissivity in a near infrared ray of a specified wavelength. CONSTITUTION:When a reference solution using an etching solution just after regulation and an actual etching solution of a measurement target during use or after use are irradiated with lights of the same intensity, the intensities of the transmitted lights of the respective solutions are determined. On the basis of them, a differential transmissivity of the ratio of these intensities is determined, and this reflects only the difference between these solutions. Thus, this differential transmissivity depends on only the absorbed water content regardless of the constituting components of the etching solution. At this time, when the irradiation is conducted with a near infrared ray, the differential transmissivity is lowered within the wavelength range of 1.2 - 1.8 mum, showing the absorption of water, and in any wavelength within this range, the absorptivity and the added water content has a proportional relation. Thus, the water content can be easily known by the absorption measurement with a near infrared ray in this range.</p> |
