| 摘要 |
PURPOSE:To automate the control of etching solution through recovering concentration of the etching solution in process of copper etching using copper chloride etching solution by a method wherein oxydation current of cuprous ion is measured and controlled to a specified value by adding oxidizing agent and liquid composition adjusting agent. CONSTITUTION:When copper and copper alloy are etched by the copper chloride etching solution in an etching device 7, the etching solution is circulated by a pump 14 through a Cu<+> concentration detector 11 and a specific gravity detector 12 to the device 7. In the liquid in the Cu<+> concentration detector 12, an indicator electrode and an opposite electrode are given constant polarization potential to measure oxidation current of Cu<+>, so that Cu<+> concentration is measured from the relation between the premeasured oxydation current and Cu<+> concentration. When the measured Cu<+> concentration and the specific gravity reach the specified value, specific amount of H2O2, HCl and water are added from H2O2 tank 9 and HCl tank 10 through pumps 15, 16, and a controller 17. In this manner, the concentration of etching solution is automatically maintained in the specified range, thereby providing a uniform etching rate. |
