There are handling considerations during manufacture and process time lapse
between a and b side reflow considerations for double sided assembly for
silver. I know of no problems with this finish.

As for enig I know of plenty of issues but I am sure others will chip in on
this. One of the larger Contract manufacturers (the one that got taken over
recently and starts with an S) actually has a rule that an ENIG finish
specified on a drawing infringes its design/manufacturing rules due to the
historic issues they experienced with the finish.

 
 
John Burke
 
(408) 515 4992
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Carl VanWormer
Sent: Friday, August 10, 2007 2:07 PM
To: [log in to unmask]
Subject: [TN] Silver PCB finish and reliability (question)

For non-BGA, surface mount boards, we have always ordered HASL boards.  In
our progress towards ROHS compliance, management has changed the default
specification to ENIG.  Our board house has HASL, ENIG, and Silver as
options, with Silver at about the same price as HASL and ENIG with a
significant premium (along with a 2 to 3 days added to the processing time).
When I asked management why we couldn't use Silver, I was told that there
are significant problems with the Silver processed boards (with no real
explanation).  

My question to the Group:  Is there any good reason to avoid Silver as a
surface finish on my consumer and industrial boards?  

Your scary stories are welcomed . . .

Thanks,
Carl





Carl Van Wormer
Cipher Systems
1800 NW 169th Place, Suite B-100
Beaverton, OR  97006
Phone (503)-617-7447 extension 20    




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