7. Immersion silver
Immersion sliver is difficult between OSP and ENIG.Even when it exposed to hot, wet and pollution, silver can keep good weldability but will lose its luster.The I-Ag does not have the good physical strength of the ENIG, because there is no nickel below the silver layer.
Merits: Simple process, suitable for lead-free soldering SMT.The surface is very smooth, low cost, suitable for fine lines.
Demerits: Storage conditions are high and easy to pollute;Problems with welding strength (microcavity);It is easy to show the phenomenon of electrical migration and cavitating in the copper under the resistance welding film.