Method for Stripping/Etching of Metallization on Circuit Boards
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-18
A method is described for stripping copper and other metallurgies used in circuit fabrication. This method comprises an electrolytic cell in which copper is made anodic, and the electrolyte is either a sulfuric acid solution or a sulfuric acidic and complexing agent, i.e., a mixture of EDTA and citric acid. Upon the passage of an electric current, copper dissolves, or: Cu ---> Cu+2 + 2e- Since the acidic medium is sulfuric acid, the net reaction will be: H2+S042 + Cu+2 ---> CuS04 + H2 Both products, copper sulfate and hydrogen gas, do not require waste treatment. Hydrogen is released at the cathode as hydrogen gas, and copper sulfate is normally used in copper plating bath formulations.