Dear Technos,

I have SnPb37 joints with 4-8% Au that did not fail thermal cycling, no cracks, pass electrical tests like a charm. This kinda contradicts J-STD-001 and common knowledge, so I would appreciate some insider info regarding Au embrittlement, to help me figure this one out.

I know one could write volumes on this, but I'm sure the questions below can be answered in a brief manner.


*         How did Au embrittlement end up being a reliability issue? Real catastrophic failures?

*         What is the effect on the long term reliability of solder joints?

*         What screening method creates catastrophic failure of embrittled joints (mechanical shock, thermal cycling, vibration, etc.)?

*         It looks like the embrittlement process goes on as long as there's Au to combine with Sn. What is the speed of this reaction? Otherwise said, how long does it take for a joint with high Au content to become brittle?

*         Has anybody screen for embrittlement? Or, anyone tried to maximise embrittlement (e.g. 100 hours @ 150 C) and then screened the hardware?

*         Anything else I should know?

Thanks,

Ioan Tempea, P. Eng.
Manufacturing Engineer, Satellite Systems

[cid:[log in to unmask]]

MacDonald, Dettwiler and Associates Corporation, 21025 Trans-Canada Highway, Ste-Anne-de-Bellevue, QC, Canada H9X 3R2
Tel: +1-514-457-2150 x3556
www.mdacorporation.com<http://www.mdacorporation.com/>

This e-mail, and any attachments, are intended solely for the use of the intended recipient(s) and may contain legally privileged, proprietary and/or confidential information. Any use, disclosure, dissemination, distribution or copying of this e-mail and any attachments for any purposes that have not been specifically authorized by the sender is strictly prohibited. If you are not the intended recipient, please immediately notify the sender by reply e-mail and permanently delete all copies and attachments. This email is for informational purposes only and shall not be interpreted to authorize or conclude a binding agreement between MDA and any other party unless this email contains or is accompanied by an express written confirmation of MDA's intention to enter into a binding agreement, such confirmation shall only be provided by an authorized representative of MDA.