I believe... (doing this from memory), that if you have a RoHS BGA, you need
to process the entire board as RoHS. (But I believe you already said that.)

You will have issues due to the lead-free BGA needing to be processed at a
higher temperature.

If you don't, you will need to have the BGA's reballed with leaded solder
(which is a pain, and costly).

I know a company that went through this nightmare a while ago, and learned
this lesson.


This also means that you need to have the PCBs fabricated that can take the
higher temps. You are no longer using FR-4, but boards with a Tg compatible
with lead-free.

As to the reliability of RoHS, I don't have any articles that I can point you
to. It seems that from my RoHS research, for every article I found that says
lead-free is unreliable, there is another that says it is.

From my personal experience, gut feeling and old-age kicking in, I don't have
a good feeling using RoHS.

I'm sorry I don't have any articles or web sites I can point you to. I'm sure
that you will locate some.

If you want to hear anecdotal stories about my RoHS experiences, I will be
happy to regale you with them - off-line.

Regards,

James


Quoting Dee Stover <[log in to unmask]>:

> Hi all,
> 
> I need to find some written data on the long term reliability of rohs 
> assemblies.  We don't have comply with rohs but can only get the 
> parts in rohs, with BGA's being the main drive for rohs compliant solder.
> 
> Just had an assembly vendor say that a rohs bga can be assembled with 
> eutectic solder paste with good results.  2 other assembly shops say 
> that is not recommended.  Is there any real studies or data available 
> that provides the real answer?  Also studies and data for the 
> reliability of rohs?  We need our boxes to work for 10 years or more.
> 
> Thank you for your time.   What a great network for people to share 
> knowledge.  I will also be going through PCD&F and google to 
> (hopelessly behind on my reading)
> 
> :-) Dee Stover  [log in to unmask]   520-318-8489
> Tech Associate II
> National Optical Astronomy Observatories
> www.noao.edu 
> 
> 
> 
> ______________________________________________________________________
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