Just want to thank everyone for the info provided on the Nickel
thickness question.  After relaying as much info as possible back to our
customer, it turns out that they have a typo on a standard note they use
for plating -- their decimal point is off and it should be .00005 (50
microns!)

Thanks for all your help :-)

-Carrie

-----Original Message-----
From: Reeves, Tim R. [mailto:[log in to unmask]] 
Sent: Wednesday, August 25, 2004 11:52 AM
To: Morse, Carrie
Subject: RE: Low Stress Plating Question

I don't consider myself an expert, but I think I know enough to answer.
1. The nickel is a barrier between gold and copper, which form a brittle
intermetallic to be avoided. The gold is just there to prevent oxidation
of the nickel, which is, when oxidized, is very difficult to solder to.
2. 500 microinches is a lot of nickel. Typically, 150 or 200 microinches
is specified, sometimes less.
Seems like other answers given agree pretty much with this.


Tim Reeves
Tyco Electronics | Printed Circuit Group | Dallas Division



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Morse, Carrie
Sent: Tuesday, August 24, 2004 6:07 AM
Subject: Low Stress Plating Question


For all you Plating Experts
We have a customer specifying 500 micro inches minimum of Low Stress
Nickel under 3-5 micro inches of Gold.
 
1.  What is the purpose of the Ni?  Is it to aid in bonding the gold?
2.  Is 500 micro inches too much?  What are board houses capable of
doing without damaging the board and....what would board houses like to
see for a minimum specification on a note?
 
Thanks,
Carrie

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