Thank you everyone! I think from all your replies I have the answer. Our application would work with plating down to 15 microinches. That is well below the 30 that several of you have mentioned. With some additional testing at say 20 microinches I think we'll be OK.

Thanks again,

KennyB

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Valerie St.Cyr
Sent: Wednesday, October 27, 2004 8:38 AM
To: [log in to unmask]
Subject: Re: [TN] Gold Board


Ken,

Gold embrittlement is more a concern for fine pitch surface mount joints
where the percentage volume of gold grows as the absolute volume of paste
decreases. That being said, the gold thickness should still be kept low.
The pads which need to be gold will drive the final decision; why are
those pads gold and what does that mean for their necessary gold
thickness? If they are "thick" electrolytic gold, over 30 microinches,
then typically the fabricator would make the board in 2 gold passes: one
pass to put on a light sacrificial thickness of gold; then they would mask
off the whole board except for the pads of interest; then another pass in
gold to plate up those pads thicker - to 30 or 40 or 50 microinches
(whatever is called for). This 2 pass processing adds cost. If the gold
pads can be 25 microinches or less, then they can just gold plate the
whole board in one pass.

For all of this I am assuming that this is electrolytic gold over
electrolytic nickel.

Valerie

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