| 摘要 |
PURPOSE:To measure the concn. of a chelate agent in a chemical copper plating liquid and to enable continuous and automatic control of concn. by adding Fe<3+> exceeding slightly the molar concn. of the entire chelate agent contained in the chemical copper plating liquid to said liquid and measuring the oxidation reduction potential thereof. CONSTITUTION:A specified amt. of a copper plating liquid consisting of Cu ion, chelate agent, reducing agent and alkali metal hydroxide is collected from a plating cell 1 by means of a multiplextube pump 2 and a titrating liquid 3 consisting of an aq. soln. of FeCl3 and HCl is drawn from the 1st titrating liquid tank in measuring the chelate agent such as ethylenediamine tetraacetic acid as the chelate agent in said copper plating liquid. Both liquid are mixed and the electrode potential thereof is measured with a Cu ion detecting cell 7 and is inputted to a device 8 for controlling the concn. of the Cu ion. The liquid emitted from the cell 7 is mixed with a specified amt. of the 2nd titrating liquid 11 by a pump 2 in a Tee pipe 4-2 and the concn. is measured with a chelate agent detecting cell 12 and the measured valve is inputted to a control device 13. If the concn. is lower than the respective set values of the devices 8, 13, solenoid valves 9-1, 9-2 are opened and the Cu ion and chelate agent are respectively replenished to the cell 1 from a Cu ion replenishing tank 10 and a chelate agent replenishing tank 14. |
