IPC 4553A

This specification sets requirements based on performance criteria for the use of Immersion Silver (IAg) as a surface finish for printed circuit boards. It is intended for use by chemical suppliers, printed board manufacturers, electronics manufacturing services (EMS) companies and original equipment manufacturers (OEM). IAg is a thin immersion deposit over copper. It is a multifunctional surface finish, applicable to soldering. It may also be applicable for some press fit connections and as a contact surface. It has the potential to be suitable for aluminum wire bonding. The immersion silver protects the underlying copper from oxidation over its intended shelf life. Exposure to moisture and air contaminants, such as sulfur and chlorine, may negatively impact the useful life of the deposit. The impact can range from a slight discoloration of the deposit to the pads turning completely black. Proper packaging is a requirement. Note that, in this revision, both a single thickness range is in place and an upper limit for immersion silver thickness has been established.