| 摘要 |
PURPOSE:To maintain and control the effective power of an etching soln. at a desirable level during use by controlling the amt. of the hydrochloric acid to be replenished in accordance with the detected value of the concn. of the hydrochloric acid in the etching soln. during use and replenishing hydrogen peroxide in accordance with said replenishing amt. CONSTITUTION:Part of the etching soln. 100 in an etching soln. tank 1 is circulated to a tank 50 for detecting the concn. of hydrochloric acid through a pipe 3b while the soln. is cyclically used, via a pipe 3a and a nozzle 4 by a pump 2. Concentration of hydrochloric acid is detected by an apparatus 5 for detecting the concn. of hydrochloric acid. A hydrochloric acid 80 is replenished from a hydrochloric acid containing tank 8 in order to maintain the concn. of acid contd. in the soln. 100 between 0.1-5mol, more preferably between 1.5-2.5mol, via a mol controller 6 and a fixed displacement pump 7 in accordance with the concn. value of the hydrochloric acid detected continuously. The hydrogen peroxide 120 of the stoichiometric ratio of the chemical reaction with respect to the above-mentioned amt. of the hydrochloric acid to be replenished is replensihed, via a controller 10 and a pump 11, from a hydrogen peroxide containing tank 12 to the soln. 100. |
