AUTOMATIC CONTROL METHOD FOR ELECTROLESS PLATING BATH

• Main Authors: NAWAFUNE HIDEMI, MIZUMOTO SHOZO, NISHIKAWA TETSUJI, HAGA MASAKI
• Format: Patent
• Language: English
• Published: 15.02.1994
• Edition: 5
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; METALLURGY; PHYSICS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TESTING

PURPOSE:To speedily analyze the concentrations of components and to simply execute the automatic control of an electroless plating bath by detecting a reducing agent and a complexing agent in the plating bath by an infrared spectroscopic method and calculating and replenishing the necessary quantity thereof. CONSTITUTION:The electroless plating bath consisting essentially of a metallic salt, a complexing agent forming a complex salt with the metal and a reducing agent are stored in the electroless plating bath 1. A sample of the plating bath is sent to an infrared spectroscope unit 3 to detect the absorbancy thereof in the infrared region. The concentrations of the complexing agent and the reducing agent in the plating bath are calculated in a controlling means 14 based on the detected absorbancy. The necessary quantity is obtained by comparing each of the calculated concentrations with a set concentration for each thereof. Solenoid valves 11, 13 are controlled based on the necessary quantity, thereby replenishing the necessary quantity of the complexing agent and the reducing agent from supply sources 5, 6.