Pascal,
What has developed since this last email? Were you able to quickly
change to Au/Au and eliminate the problem?
It does not sound like this was a tin whisker problem - just an
observation. Do you have any data on how long the whiskers were?
Thank you.
Regards,
Karl Sauter
Sun Microsystems
650-786-7663
Pascal Guiheneuf wrote On 01/27/06 07:41,:
>Is this a continuous 7 amp current or power cycled on/off ? Continuous
>What is the material of the mating contact ? Tin/Tin, and we looks for moving to Au/Au. No Tin/Au because of freeting corrosion and galvanic corrosion.
>Is their some vibration in the test ? No vibration, no thermal schock, but it is a contact connexion.
>What is the humidity level in the test ? I do not know (can be checked ?)
>
>Thanks for your lights
>
>Pascal Guihéneuf
>Nortel Wireless
>
>
>
>
>-----Original Message-----
>From: Leadfree [mailto:[log in to unmask]] On Behalf Of Lester Subrattee
>Sent: vendredi 27 janvier 2006 15:59
>To: [log in to unmask]
>Subject: Re: [LF] Electromigration, high density current, Lead-free connectors
>
>
>A few questions:
>Is this a continuous 7 amp current or power cycled on/off ? What is the material of the mating contact ? Dissimilar metals (gold) may cause corrosion and assist fretting. Is their some vibration in the test ? If there is vibration, fretting can occur. What is the humidity level in the test ? Typically you need Electrical voltage, moisture and metal ions for electromigration. Tin does migrate in distilled water. No rates available. Interesting that you mention rapid growth of NiSn intermetallic. Gold with Ni underlayer finish is normally recommended for long term elevated temp operation because the growth of NiSn intermetallic is slow compared to CuSn. The only thing I know about gold migration, is in the presence of halogens. Don't have info on rates.
>
>Regards,
>LS
>
> -----Original Message-----
>From: Pascal Guiheneuf [mailto:[log in to unmask]]
>Sent: Friday, January 27, 2006 8:33 AM
>To: [log in to unmask]
>Subject: Electromigration, high density current, Lead-free connectors
>
>Hello,
>
>I am looking for information around an electromigration topic : due to = Lead-free, we moved, on a power connector, from a SnPb plating to a Tin =
>(10um) plating with a Ni barrier (5um) on copper; after 700h of a 2000 = hours 50=B0C, 7 Amps, 70=B0C ambient temperature, we are facing = failures. RCA leads to electromigration in high current densities, = accompanied with other collateral damages (Ni3Sn4 intermetallic rapidly = growing, Tin particles (maybe due to excess voiding or due to fretting = corrosion on Tin softened by the actual temperature), possibility of arc = (voiding)..), all mechanisms leading to higher resistivity, temperature = increasing, and catastrophic failure as soon as the temperature is = beyond 130=B0C (plastic limit). For your information, we have also seen = Tin Whiskers during the same experiment. The first time we succeeded in = Tin Whiskering !
>
>We would like to change to a power connector Gold plating with Ni = barrier. Is anyone of you aware of anything here, relative to high = current densities, to Gold electromigration, etc...? I couldn't find the = data around the Black's law which defines the EM, relative to Sn or Au, = and request your help.
>
>Very cordially,
>
>Regards,
>
>Pascal Guih=E9neuf
>Nortel Wireless
>
>
>
>
>----------------------------------------------------------------------------
>---Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Leadfree To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL) Search previous postings at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=3D4.3.16
>for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
>----------------------------------------------------------------------------
>---
>THIS EMAIL AND ANY ATTACHED FILES ARE CONFIDENTIAL AND MAY BE LEGALLY PRIVILEGED. If you are not the addressee, any disclosure, reproduction, copying, distribution or other dissemination or use of this communication is strictly prohibited. If you have received this transmission in error, please notify the sender immediately and delete this email. It is the policy of ACR Electronics, Inc. that no legally binding statements, representations or commitments (collectively statements) may be made by email. Any such statements must be confirmed either by facsimile transmission or by postal mail before they will have legal effect. The sender of this email is not authorised to commit the company in any way and the addressee is hereby notified of that fact.
>
>-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Leadfree To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL) Search previous postings at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
>-------------------------------------------------------------------------------
>
>-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF Leadfree
>To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
>Search previous postings at: http://listserv.ipc.org/archives
>Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
>-------------------------------------------------------------------------------
>
>
--
Karl Sauter Senior Staff Engineer, Engineering Technologies
Sun Microsystems Inc.
Office: (650) 786-7663 / x87663
E-mail: [log in to unmask]
-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-------------------------------------------------------------------------------
|
