Patent ID: 7109037

Claim:
A water-based resist stripping liquid management method of managing a water-based resist stripping liquid in an adjusting bath that is used in resist stripping equipment, wherein the water concentration of the water-based resist stripping liquid changes due to the evaporation of water, the method comprising: measuring a water concentration in the water-based resist stripping liquid in said adjusting bath, wherein the water concentration is obtained from a measured absorbance of the water-based resist stripping liquid in said adjusting bath and a calibration curve for relating the absorbance to the water concentration; measuring the concentration of a degraded component in the water-based resist stripping liquid in said adjusting bath, wherein the concentration of the degraded component is obtained from a measured electrical conductivity of the water-based resist stripping liquid in said adjusting bath and a calibration curve for relating the electrical conductivity to the concentration of the degraded component; feeding into said adjusting bath at least one of a fresh water-based resist stripping liquid, a reclaimed water-based resist stripping reclaimed liquid, and pure water; and controlling the amount of liquid fed into said adjusting bath in accordance with the measured degraded component concentration and the measured water concentration, wherein the wavelength of the measured absorbance is about 1940 nm.