AUTOMATIC CONTROL DEVICE FOR ELECTROLESS METAL PLATING

摘要

PURPOSE:To maintain the specified compsn. of a plating bath and to control a metal depositing rate at a specified rate by measuring respectively the pH of the plating bath, the metal depositing rate and the concn. of complex-forming metallic ions and adding respective replenishing liquids thereto according to the measured values. CONSTITUTION:The plating bath 1 having the compsn. which is made uniform is fed to a vessel 9 for dispensing the plating liquid from which the plating liquid is made to overflow and is returned through an absorption photometer 27 to the bath 1. A pH electrode 13 measures the pH of the bath 1 by making cyclod motion in the 1st washing tank 10 and the vessel 9. A control computer 29 controls an electromagnetic relay 30 according to the measured value thereof and feeds the pH adjusting liquid 20 by a pump 7 to the bath 1. A platinum electrode 14 measures the copper precipitating rate by making similarly cycloid motion in the vessel 9, the 2nd washing tank 11 and an electrolyzing bath 12 and the reducing agent liquid 19 is fed to the bath 1 by a pump 6. The meter 27 measures the concn. of the complex-forming metallic ions in the bath 1 and the copper ion replenishing liquid 21 is fed to the bath 1 by a pump 8.