Universal Finish SolderBond (UFSB)

UFSB is a process, which can actually provide three surface finishes, depending on the process sequence. The palladium layer is pure. No phosphorus is co-deposited The PCB manufacturers can choose the process, which give them the most benefit, because the existing Aurotech CNN ENIG process can be updated to an ENEPIG Process.

Electroless Nickel / Immersion Gold (ENIG)
If Al-wire bonding is combined with soldering then ENIG is most suitable.

Electroless Nickel / Electroless Palladium (ENEP)
In case on the PCB only soldering is performed then ENEP works well as it provides solid solder joints and is more economic than ENIG. A new feature, which gives a promising aspect for the future is the capability of this final surface to have Cu-wire bonding performed on it.

Electroless Nickel / Electroless Palladium / Immersion Gold (ENEPIG)
Should there be the necessity of also performing gold wire bonding then ENEPIG would be the right choice in terms of reliability and economy.

Au-wire bond reliability tests performed at the Fraunhofer Institute for Semiconductor
and Micro Systems Technology in Germany:

Artificial aging tests showed no deterioration of the pull force over time.