US Patent 7736445 Surface treatment method for solder joint

A surface treatment method for solder joint employs alkali buffer solution dipping the solder joint and the alkali buffer solution reacts with the solder joint thus yielding a passive layer. As the resultant passive layer forms on the surface of the solder joint, thereby prevents further corrosion and dissolution during aqueous cleaning or water dipping thereafter. In addition, the passive layer ensures a good appearance with maximum protection of the solder joint and also provides a sound reliability and a high testability of a finished electronic product equipped with the solder joint.