Tin lead, selectively applied over bare copper by "Hot Air Solder Levelling".
Electroless Nickel / Immersion Gold (ENIG)
The Rohm and Haas process are used. This is also offered as a finish for very flat requirements such as BGA pads. Deposit thickness are to IPC-4552: Nickel 3.5 to 6.3µM and Gold 0.05 to 0.12µM.
Autocatalytic Silver Immersion Gold (ASIG)
Silver is 0.15µM minimum and Gold is 0.03µM minimum.
Electroplated Gold over Nickel (for edge connectors)
1 micron of electroplated hard gold alloy over 3 microns of electroplated nickel.
Red peelable mask is applied by silkscreen to selectively mask circuit features as required.