This is clearly a chat room for scientists! no wonder they call us geeks.

The *supplier* of the PCB asked about changing ENIG to Electro.Ni/Pd/Au.
So, I deduce that the original print asked for ENIG - no mention of
palladium. If the supplier preferred  thin flash electro gold as opposed to
dealing with ENIG then I would understand that.  Besides, they won't have
to worry later about the customer coming back with a claim for "black pad".
It's the adding of the palladium to the equation that I don't understand. I
can see no reason why the *supplier* would want to add paladium.

I can see why the *customer* might want to add palladium: if you have a
board with compression socket pads that need a hard durable finish you are
likely to call out electrolytic thick nickel under gold. But you would not
want that for the SMT devices - so you end up needing a dual finish: NI/AU
with OSP; Ni/AU with Silver; Ni/AU with flash Ni/Au; Ni/AU with (did I miss
one?) ... If you add paladium to the equation you can now body plate
nickel, palladium, and then gold without extra masking steps and in and out
of film developers and strippers ....

I would ask if the *supplier* meant Ni/Pd/Au and why they would suggest
that when ENIG is the requirement - or do they think the requirement is
something else? or is this a dual-finish board that they are trying to get
to a single total body finish?

As stated by others the predominant downside that we know of with palladium
finish is availability and cost.

Valerie

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