Apparatus for controlling a developing solution.

摘要

The developing solution is used in developing photosensitive organic resin (photoresist) in a liquid crystal board manufacturing process, printed circuit board manufacturing process or the like. The apparatus comprises means, such as an absorption photometer (16), for detecting the dissolved resin concentration in the developing solution and means, such as an electric conductivity meter (15), for detecting the alkali concentration of the developing solution. Means (3, 18, 21, 22, 24, 25, 26, 28) respond to the two detection means (15, 16) by replenishing the developing solution with undiluted developing solution and/or pure water to produce a desired dissolved resin concentration and a desired alkali concentration. Thus, the developing performance of the developing solution may be kept constant. Down time is save by removing the need to stop the manufacturing process to completely change the developing solution. <IMAGE>