Electroplated nickel gold is more frequently employed on IC substrates (including PBGA), generally for binding gold wires and copper wires; but when electroplating C substrates, supplemental conductive wires should be built in the gold finger binding place prior to electroplating. The associated fee issues for PCBs are quite a few. https://10-layer-5g-communication18261.blogofchange.com/31768070/considerations-to-know-about-6-layer-one-stage-led-small-pitch-display-pcb-board