REGENERATION OF PLATING BATH BY ACIDIFICATION AND TREATMENT OF RECOVERED CHELATING AGENT IN MEMBRANE CELL

摘要

A PROCESS FOR REGENERATING ELECTROLESS PLATING BATH AND A REGENERATING APPARATUS OF ELECTROLESS PLATING BATH A process for regenerating electroless plating bath comprising the steps of: (i) continuously or intermittently taking out a part or the whole of chelating agent-containing copper electroless plating bath from an electroless plating tank, followed by removing the copper ion content from said bath; (ii) acidifying the thus obtained solution for precipitating the chelating agent therefrom and recovering the precipitated chelating agent; (iii) supplying said recovered chelating agent to an anodic cell separated by an exchange membrane from a cathodic cell having cathode, said anodic cell having copper anode, wherein in case a neutral or alkaline electrolyte solution is supplied to said cathodic cell said partitioning membrane is an anion exchange membrane or cation exchange membrane, while in case an acidic electrolyte solution is supplied to said cathodic cell said partitioning membrane is a cation exchange membrane, and applying direct current between both electrodes; and (iv) then, recycling the solution within said anodic cell to said electroless plating tank, and a regenerating apparatus of electroless plating bath including (a) a copper-precipitating means for decomposing the copper chelate contained in the electroless copper plating bath and for precipitating the copper ion, (b) a chelating agent-recovering means for changing the pH of the solution to precipitate the chelating agent and recover, and (c) an electrolytic means comprising an anodic cell and a cathodic cell separated by means of an ion exchange membrane, said anodic cell having a copper anode therein, said cathodic cell having a cathode therein.