Craigh

We published a study to that issue:

Soldering and Surface Mount Technology Vol 17 Number 2 2005 ISSN 0954-0911

In the meantime we cycled the BGAs and saw no reliability problems compared to SnPb solder.


Best regards

Guenter





_____________________________________________________

EMPA
Swiss Federal Laboratories  for Materials Testing and Research
Centre for Reliability
Guenter Grossmann,  Senior Engineer

8600 Duebendorf
Switzerland

Phone: xx41 44 823 4279
Fax :     xx41 44 823 4054
mail:     [log in to unmask]
_____________________________________________________

>>> Craig Sullivan <[log in to unmask]> 05/01/08 3:30 pm >>>
Good Morning, 

We are seeing an increased number of our customers that specify a Pb-Free
BGA when the rest of the board assembly is SnPb. Of course when we reflow at
the SnPb profiles, we don't always get a properly collapsed BGA. So we end
up reworking the BGA. We don't run a Pb-Free profile because we don't want
to risk damaging the SnPb components.

I am sure we aren't the only ones that are experiencing this. So, I have a
question or two:

What is everyone else doing when a customer requires a Pb-Free BGA on a SnPb
assembly? Many of the jobs I refer to are consignment, so it's not like we
can order the SnPb part from the get go.

What reliability issues do you see?

Are there any extra steps that your company takes to ensure the Pb-Free BGAs
collapse properly? 

Is there a "special" profile anyone uses for the best of both worlds?

What are the advantages, if any, to use a Pb-Free BGA on a SnPb assembly?

Thanks for any and all input.
Craig Sullivan
Manufacturing Engineer
MPL Incorporated
P: 607.266.0480
F: 607.266.0482
[log in to unmask] 

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