A method of consistently producing copper deposits on a substrate by electroless deposition where there is essentially no crack in the deposit

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. Electroless copper plating solutions contaning plating rate accelerators containing delocalized pi bonds and having the concentration of the reducing agent no greater than 1,2 times the concentration of the cooper ion 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. As the plating solution ages by buildup of plating reaction by-products or by-products and contamination, the quality of the copper deposited can be maintained by increasing the copper ion concentration and pH of the solution, while reducing or maintaining substantially constant the concentration of the reducing agent.