PURPOSE: To administer and control the concn. of the compsn. of a copper chloride etching soln. so as to stabilize the rate of etching, by detecting directly the concn. of the hydrochloric acid in said etching soln. and replenishing the hydrochloric acid in said etching soln. in accordance with the preset concn. of the hydrochloric acid.
CONSTITUTION: Part of the above-described etching soln. is removed to the outside of the system from an etching device provided with an etching bath, a detection bath, a regeneration bath, etc. in the stage of regenerating the etching soln. by adding hydrochloric acid and H2O2. The soln. is diluted by using a soln. of a specified concn. prepd. from an aq. soln. of 0.01W100g/gl alkali of NaOH or the like or water, and the concn. of the hydrochloric acid is detected continuously or intermittently. A soln. of a specified concn. prepd. from an aq. soln. of 10W200g/l alkali is used as the alkali to be used in titration for the purpose of said detection. Water or hydrochloric acid is replenished to a part of said etching device in accordance with the preset range of the concn. of the hydrochloric acid to control the concn. of the hydrochloric acid in the etching soln. As a result, the variance in the concn. of the hydrochloric acid in the soln. is reduced, the balance between H2O2 and the hydrochloric acid is maintained to be constant and the stable etching is accomplished for a long period of time.
KOKUBU JIYUN
NAMIKAWA YOSHIJI
OSHIDA YUTAKA
