[tinwhiskers] Re: - RoHS & BGAs!!!

  • From: "Parnagian, Edward" <ed.parnagian@xxxxxxxxxxx>
  • To: "tinwhiskers@xxxxxxxxxxxxx" <tinwhiskers@xxxxxxxxxxxxx>
  • Date: Wed, 18 Feb 2009 17:51:18 +0100

Hi, Werner!

If you take a look at Figure 1 of the attached PDF, you will see impact 
performance compared against SnPb.  Of note is the easily missed performance 
bars for SAC305 and SAC387.  The two formulations that the most attractive from 
an impact perspective are SAC with 0.13% Manganese and SAC with 0.2% Cerium.  
Given that other reports demonstrate that adding Cerium stimulates whisker 
growth, I'm interested in following development of the manganese formulation.

Best regards,
Ed

From: tinwhiskers-bounce@xxxxxxxxxxxxx 
[mailto:tinwhiskers-bounce@xxxxxxxxxxxxx] On Behalf Of Werner engelmaier
Sent: 2009 Feb 18 11:20 AM
To: tinwhiskers@xxxxxxxxxxxxx; Parnagian, Edward
Subject: [tinwhiskers] Re: - RoHS & BGAs!!!

Hi Ed,
You say: "use only low silver BGAs. SAC105 balls held down with SAC305 perform 
almost as well as SnPb" and "SAC105 with a sprinkling of magnesium, the impact 
strength is actually superior to that of SnPb, and the thermal cycle life is 
still much better, as well."
Do you have any data you can share?
There are data from Celestica that show that cyclic fatigue life decreases with 
decreasing Ag content.

Werner







-----Original Message-----
From: Parnagian, Edward <ed.parnagian@xxxxxxxxxxx>
To: tinwhiskers@xxxxxxxxxxxxx <tinwhiskers@xxxxxxxxxxxxx>
Sent: Wed, 18 Feb 2009 10:51 am
Subject: [tinwhiskers] Re: - RoHS & BGAs!!!

Hani,










Most of us in high reliability industries - mine is medical defibrillators -





don't generate enough volume to be able to convince an Analog Devices to run





separate ball formulations.  My advice is to talk with someone like Amkor who at





one time was willing to obtain dies from the original manufacturer and then





package the dies with tin lead (SnPb) balls. The catch is that some original





manufacturers are unwilling to give them permission to do so and/or won't honor





warranty on the device.  Do NOT try reballing devices that have already been





balled; you will not get consistent metallurgy between the balls and the die.





Some will be good, and some will be terrible.










Alternatively, build your design for lead-free but use only low silver BGAs.





SAC105 balls held down with SAC305 perform almost as well as SnPb.  If you can





find SAC105 with a sprinkling of magnesium, the impact strength is actually





superior to that of SnPb, and the thermal cycle life is still much better, as





well.










The overall market place has still not come to face the harsh realities





(limitations) of the early decisions associated with SAC305, but a lot of people





are desparately working on it.  My guess is that the transition to a real





solution without lead is a decade away - at best.  Until then lots of pain for





people whose products have to last more than a couple of years.










Best regards,





Ed










-----Original Message-----





From: tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx> 
[mailto:tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx?>]





On Behalf Of Bob Landman





Sent: 2009 Feb 18 9:51 AM





To: tin whiskers forum





Cc: <tinwhiskers@xxxxxxxxxxxxx<mailto:tinwhiskers@xxxxxxxxxxxxx>>





Subject: [tinwhiskers] Re: - RoHS & BGAs!!!










Hani,










Some companies still offer BGA in tin-lead (Lattice Semi is one of





them). I recently helped to convince Analog Devices to put tin-lead





balls on a MEMS device for an aerospace firm as the devices were





popping off after reflow.










Your hardware designers need to push the envelope harder. Demand tin-





lead solder balls.










Bob










P.S. Later today I'll get you other papers on the subject.










Sent from my iPhone










On Feb 18, 2009, at 9:24 AM, "AL-Yousef, Hani 
E"<Hani.AL-Yousef@xxxxxxxxxxxxxxxxxxxx<mailto:Hani.AL-Yousef@xxxxxxxxxxxxxxxxxxxx>





 > wrote:










> Bob,





>





> We are forced to use SAC BGA since that is the only thing available





> for





> that part. I guess your advice would be, look for another part that





> comes in tin lead.  I have to work on the firmware guys for that.





>





> Would happen to have any white papers, experiments documentations,





> application notes that state the concerns that you shared?





>





>





>





> Thanks,





> Hani





> -----Original Message-----





> From: 
> tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx>





> [mailto:tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx?>]
>  On Behalf Of Bob Landman





> Sent: Wednesday, February 18, 2009 12:19 AM





> To: tinwhiskers@xxxxxxxxxxxxx<mailto:tinwhiskers@xxxxxxxxxxxxx>





> Subject: [tinwhiskers] Re: - RoHS & BGAs!!!





>





> Hani,





>





> Your equipment should be exempt from RoHS requirements.  Do not use





> SAC





> solders or SAC BGAs if you expect a 20+ year life.  The mechanical





> vibration from switching your reclosers will shake the BGAs off their





> pads.  Mechanical shock is the nemisis of SAC alloys, especially at





> low





> temperatures.  Outside on a pole in Alaska is going to cause failures.





>





> See





> http://ap.pennnet.com/display_article/312379/36/ARTCL/none/none/1/Detect





> ing-Brittle-Fracture-Failures/





>





> Bob Landman





> H&L Instruments, LLC





> www.hlinstruments.com<http://www.hlinstruments.com>





>





>





>





> -----Original Message-----





> From: 
> tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx>





> [mailto:tinwhiskers-bounce@xxxxxxxxxxxxx<mailto:tinwhiskers-bounce@xxxxxxxxxxxxx?>]
>  On Behalf Of AL-Yousef,





> Hani E





> Sent: Friday, February 13, 2009 11:27 AM





> To: tinwhiskers@xxxxxxxxxxxxx<mailto:tinwhiskers@xxxxxxxxxxxxx>; TechNet 
> E-Mail Forum;





> RoHSUSAPushback@xxxxxxxxxxxxxxx<mailto:RoHSUSAPushback@xxxxxxxxxxxxxxx>; 
> SMART Group smart-e-link





> Subject: [tinwhiskers] - RoHS & BGAs!!!





>





>





> Hello All,





>





> I am in the hunt for information on how to best evaluate whether





> underfill is needed for SAC BGA when soldered with SAC paste.





>





> Also, part of my evolution is to find the right solder, flux and





> chemistry to clean afterwards. Further specify a cleanliness level.





>





> I guess one has to find to the right test to use to evaluate these





> parameters.





>





> Our products are expected to last for 20+ years while mounted





> outside on





> a power distribution pole mounts.





>





>





> I can use all the help I can get.





>





> Thanks





> Hani





>





>





>





>





>





>




















The information contained in this message may be confidential and legally





protected under applicable law. The message is intended solely for the





addressee(s). If you are not the intended recipient, you are hereby notified





that any use, forwarding, dissemination, or reproduction of this message is





strictly prohibited and may be unlawful. If you are not the intended recipient,





please contact the sender by return e-mail and destroy all copies of the





original message.





________________________________
The information contained in this message may be confidential and legally 
protected under applicable law. The message is intended solely for the 
addressee(s). If you are not the intended recipient, you are hereby notified 
that any use, forwarding, dissemination, or reproduction of this message is 
strictly prohibited and may be unlawful. If you are not the intended recipient, 
please contact the sender by return e-mail and destroy all copies of the 
original message.

Other related posts:

  1. Home
  2. tinwhiskers
  3. Archive
  4. 02-2009