METHODS AND APPARATUS FOR TREATING ELECTROLESS PLATING BATHS

摘要

Apparatus and methods for removing formate ions from electroless metal plating baths employing formaldehyde as a reducing agent and typically comprising polyvalent anions as metal chelant and/or counterion. The apparatus and methods employ anion filtration to separate polyvalent anions from monovalent formate ions and ion exchange units to remove metal and metal chelant species from formate-containing streams. Preferred aspects of this invention provide apparatus and methods for removing formate from electroless copper plating baths.