Hi Dave,
Yes, also MSL plays an important role.
About the cracks due to Pb migration; We have seen the same happening in some experiments.
regards
Jowan
________________________________
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, December 09, 2009 1:49 PM
To: TechNet E-Mail Forum; Iven, Jowan
Cc: [log in to unmask]
Subject: Re: [TN] SnPb SOLDER BALLS WITH SAC SOLDER PASTE
Hi Jowan - when you run a component thru a thermal process you not only have to consider the impact of temperature but also the impact of moisture sensitivity. As you detailed, many tin/lead components are thermally robust enough for a lead-free soldering process. Unfortunately the moisture sensitivity level (MSL) of tin/lead components makes them less robust in a lead-free soldering process and raises the potential of having a latent field failure. Forward/backward compatibility of mixed systems can be a big issue if there is a lack of due diligence. One additional comment - the JCAA/JGPP Leadfree consortia project and the folks at AIM Solder have documented that in some cases, lead migrates to the solder joint crack interface when tin/lead solder (i.e. a solderball or a surface finish) is processed in leadfree soldering process resulting in greater solder joint integrity degradation.
As a side note, Iowa is having a wonderful blizzard with 12 inches of powder snow and 25-30 mph winds today! Heads up East Coast folks, the storm is on its way.
Dave Hillman
Rockwell Collins
[log in to unmask]
"Iven, Jowan" <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
12/09/2009 02:24 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
"Iven, Jowan" <[log in to unmask]>
To
[log in to unmask]
cc
Subject
Re: [TN] SnPb SOLDER BALLS WITH SAC SOLDER PASTE
I agree with you Ioan,
Most leaded bga's have maximum temperature specifications below the lead-free process.
So why worry about the balls when the bga is electrically damaged?
Regards
Jowan Iven
Process Engineer
Neways Advanced Applications
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: Tuesday, December 08, 2009 2:54 PM
To: [log in to unmask]
Subject: Re: SnPb SOLDER BALLS WITH SAC SOLDER PASTE
Hi Lee,
First, how would you reflow a leaded BGA at LF temperatures without popping it?
Then, the closest paper I have, coming your way in a second, is something from AIM saying that Pb will deposit at the points that cool the slowest, making brittle Pb pockets at the interface with the pad.
Regards,
Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
T | 450.967.7100 ext.244
E | [log in to unmask]
W | www.digico.cc
N'imprimer que si nécessaire - Print only if you must
------Original Message------
From: Lee Whiteman
Sender: TechNet
To: [log in to unmask]
Subject: [TN] SnPb SOLDER BALLS WITH SAC SOLDER PASTE
Sent: Dec 8, 2009 08:17
I know about the problems with soldering BGAs with SAC solder balls and
SnPb solder paste and read plenty of papers pro and con.
I heard about a report where if you solder BGAs with SnPb solder balls
using SAC solder paste, the resulting solder joint will be unreliable. Has
anyone heard of anything like that? If there are any cross-sections or
papers that you can share with me, that would be great.
Thanks again.
Lee Whiteman, PMP
Senior Member Engineering Staff
L-3 Communications East
Telephone: (856) 338-3508
FAX: (856) 338-2906
E-Mail: [log in to unmask]
SENTEC
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts 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
-----------------------------------------------------
This e-mail and any attachment is confidential and may be legally privileged or otherwise protected from disclosure. If you are not the intended recipient, please notify the sender immediately by returning this e-mail. Neways Electronics NV is not responsible for the improper or incomplete transmission of any e-mail, or for any delay in its receipt.
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts 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
-----------------------------------------------------
This e-mail and any attachment is confidential and may be legally privileged or otherwise protected from disclosure. If you are not the intended recipient, please notify the sender immediately by returning this e-mail. Neways Electronics NV is not responsible for the improper or incomplete transmission of any e-mail, or for any delay in its receipt.
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts 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
-----------------------------------------------------
|
