Yep, big trouble.

Check with Dave Hillman on TN, he very recently wrote a paper showing what is happening. You have a good intuition, the 2 alloys will not completely mix giving reliability issues of which the most important is cracking at the interface with the PCB.

Regards,
Ioan

> -----Original Message-----
> From: DesignerCouncil [SMTP:[log in to unmask]] On Behalf Of Brooks,Bill
> Sent: Tuesday, August 09, 2005 12:20 PM
> To:   [log in to unmask]
> Subject:      [DC] Lead-free design changes and impacts?
> 
> There is one potential change that I really have not had time to look into
> yet... maybe someone else has already looked at the BGA packages and
> determined whether or not the 'lead-free' solder balls under the packages
> will be an issue if you're soldering process does not go lead-free???...
> Those with RoHS exemptions will still be buying lead-free parts because they
> can't get the tin/lead versions anymore, they will be phased out... Will
> they run into soldering problems if the lead-free solder balls don't
> collapse at eutectic solder melting temps?
> 
> Best regards,
> 
> Bill Brooks - KG6VVP
> PCB Design Engineer, C.I.D.+, C.I.I.
> Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
> Datron World Communications, Inc.
> _______________________________________
> San Diego Chapter of the IPC Designers Council
> Communications Officer, Web Manager
> http://dcchapters.ipc.org/SanDiego/
> http://pcbwizards.com
> 
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