Understood & Thanks!!!

Rich Kraszewski 
Advanced Manufacturing Engineer - KEDS
Phone:  260.925.8919
 
 
 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nowland, Russell
Howard (Russell)
Sent: Wednesday, June 16, 2004 9:27 AM
To: [log in to unmask]
Subject: Re: [TN] Yellow Discoloration of Immersion Silver Boards


Richard,

With a slight discoloration they will solder.  As the discoloration
increases so does the solderability issues.  What you are probably
seeing is silver sulfide layer forming.  There are several possible
causes one being the finished product got to close to the acid tanks at
the fab-house.  The sulfur from the tanks will cause the silver sulfides
to form.  I have also seen paper sheets used in the packaging get trace
amounts of sulfur imbedded in them a when placed in the packages cause
the discoloration.  Also, if you are in a highly polluted area or have a
high sulfur content in the air you will get the discoloration.  I am
told the silver sulfides are benign and not a concern.  I can tell you
it can get bad enough to make it very difficult to process and even
test.  We have had problems with making contact on bed-of-nails testers
because of the tarnishing.

You could also have a problem with the OSP used to protect the silver.


Russell Nowland
Lucent Technologies
Quail Springs Parkway Plaza
14000 Quail Springs Parkway. Suite 300
Oklahoma City, OK 73134
Phone: 405-302-1660
Fax: 405-302-1622
Cell: 405-203-0034
email: [log in to unmask]


-----Original Message-----
From: Richard Kraszewski [mailto:[log in to unmask]]
Sent: Wednesday, June 16, 2004 9:13 AM
To: [log in to unmask]
Subject: [TN] Yellow Discoloration of Immersion Silver Boards


We are seeing yellow discoloration of Immersion Silver Boards right out
of the package from our board house.  They seem to solder fine, however
this is causing some concern with our customer.  I suspect that it could
be a thin film of  silver bromide or silver carbonate both which are
yellow powders.

Any one seen this before?

What is it?

How does the board house remedy this situation?

Any associated concerns or other bits of wisdom?

I would truly appreciate any input.


Rich Kraszewski

Advanced Manufacturing Engineer - KEDS

Phone:  260.925.8919









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