But, depending on the silver and tin content, you get different intermetallic structures for the same reflow profile, which can have an effect on reliability during thermal cycling? 


Amol Kane
M.S (Industrial Eng.)
Process Engineer
Harvard Custom Manufacturing 
941 Route 38  Owego, NY 13827
Phone: (607) 687-7669 x349
[log in to unmask]

 -----Original Message-----
From:   TechNet [mailto:[log in to unmask]]  On Behalf Of Werner Engelmaier
Sent:   Wednesday, January 18, 2006 3:00 PM
To:     [log in to unmask]
Subject:        Re: [TN] RoHS board finish

Hi Amol,
There is no reason that you should see a difference in accelerated thermal
cycling and/or long-term reliability if using immersion Ag and Sn. In both the
iAg and iSn surface treatments, you are soldering to the underlying Cu.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com


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