METHOD OF CONSISTENTLY PRODUCING COPPER DEPOSIT ON A SUBSTRATE BY ELECTROLESS DEPOSITION WHICH DEPOSIT IS ESSENTIALLY FREE OF FISSURES

摘要

Electroless metal plating solutions are formulated and controlled to provide high quality metal deposits by establishing the intrinsic cathodic reaction rate of the solution less than 110% of the intrinsic anodic reaction rate. Methods are provided to formulate electroless copper plating solutions which can deposit copper on printed wiring boards of quality sufficient to pass a thermal stress of 10 seconds contact with molten solder at 288 DEG C without cracking the copper deposits on the surface of the printed wiring boards or in the holes. The ratio of the anodic to the cathodic reaction rates can be determined by electrochemical measurements, or it can be estimated by varying the concentration of the reactants and measuring the plating rates.