Process for regenerating an electroless copper plating bath

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution by electrolysis, the anodic current density i.sub.+ not exceeding 100 A/m.sup.2 the bath circulation rate being approximately 10 to 50 volumes/h;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution by electrolysis the anodic current density i.sub.+ not exceeding 100 A/m.sup.2 , the pH value of the withdrawn bath being maintained constant during electrolysis;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution by electrolysis, the anodic current density i.sub.+ not exceeding 100 A/m.sup.2 ;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution by electrolysis, the anodic current density i.sub.+ not exceeding 100A/m.sup.2 the anodic current density being reduced during electrolysis as the electrolysis characteristic drops;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution by electrolysis, the anodic current density i.sub.+ not exceeding 100 A/m.sup.2 the anodic current density being reduced during electrolysis in steps;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution to a value below 20 mg/l by electrolysis, the bath circulation rate being approximataely 10 to 50 volumes/h, the pH value of the withdrawn bath being maintained constant during electrolysis, the anodic current density i.sub.+ not exceeding 100 A/m, the anodic current density being reduced during electrolysis according to the electrolysis characteristic;
• acidifying the bath solution thus obtained by precipiting the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.

A process for regenerating a complexing agent in an electroless copper plating bath, comprising the steps of:

• withdrawing the bath solution containing the complexing agent from the electroless plating bath;
• reducing the copper content in the withdrawn bath solution to a value below 20 mg/l by electrolysis, the bath circulation rate being approximately 10 to 50 volumes/h, the pH value of the withdrawn bath being maintained constant during electrolysis, the anodic current density i.sub.+ not exceeding 100 A/m.sup.2, the anodic current density being reduced during electolysis in steps;
• acidifying the bath solution thus obtained by precipitating the complexing agent and recovering same;
• dissolving the recovered complexing agent in an alkaline electrolyte solution;
• and
• returning the solution to the electroless copper plating bath.