Abstract
The application of glyoxylic acid as an alternative reducing agent to formaldehyde for full build electroless copper plating process was investigated. Excellent mechanical properties of deposits were obtained with the conventional additives, which were used for the formaldehyde bath. The rate of the Cannizaro reaction of glyoxylic acid was reduced by using KOH instead of NaOH and by maintaining a low bath pH. The solubility of potassium oxalate, which is the by-product salt of the plating reaction and Cannizarro reaction, is much higher than that of sodium oxalate. The bath life of the KOH bath was five times longer than that of the NaOH bath. The test boards plated with developed electroless copper plating solution showed an excellent level of reliability for the through hole interconnection.
