Hi folks,
I hope your Labor day weekend was good... I spent most of it glued to FOX,
CNN, and MSNBC worrying for the folks in Louisiana and Mississippi and the
Southern United States in general and looking for some relief for the
victims of the Hurricane Katrina and the flooding... What a disaster! Last
Thursday our company donated over 100,000 dollars worth of radio equipment
to the California National Guard who took the equipment with them to help in
New Orleans. It was truly awesome to see some decisive action down there
finally, the situation in New Orleans was absolutely horrible. I hear there
are numerous efforts in many states to open shelters and even private
citizens are opening their homes to displaced residents of the hard hit
region. The spirit of the United States citizens is just awesome.
On another note, regarding the lead free 'craze' still going on... I noticed
today the Senior Editor at Chip Scale Review magazine also echo's a similar
sentiment regarding the 'lemming like' rush to adopt Lead-free soldering at
the threat of the EU restricting electronics products from access to their
markets if they contain normal tin/lead solder. It bothers me a lot that
they move to do this without the science to back this assertion of potential
environmental contamination if the products end up in the landfills... but
they will affect the industry no matter what, as we can all observe, science
or not.
His story can be found at:
http://www.chipscalereview.com/issues/0805/article.php?type=feature&article=
f5
How can we swing the pendulum the other way back to more 'rational' thinking
and behavior...? I can only see severe reliability issues for the industry
ahead... it really worries me. I just don't have the confidence in the lead
free alloys and processes or materials being anywhere near as reliable as
the traditional tin/lead soldering process has been. Even with all the
reassurances the board vendors have been giving regarding the ability to
solder with silver/copper/tin alloys they still have the 'tin whisker' issue
and there is no solution for that problem yet... also I really worry about
the ductility of the lead free solders being adequate enough to keep
structural cracks from developing in the solder joints much sooner than
traditional tin/lead solders under vibration and thermal shock or
environmental thermal cycling.
It doesn't look good from here for the world's electronics industries 'post
RoHS'...
We shall see... let me know if you find any solution that is truly a
replacement for tin/lead that really works. So far I am not that encouraged
by what I have seen.
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, August 09, 2005 2:09 PM
To: [log in to unmask]
Subject: RE: [TN] [DC] Lead-free design changes and impacts?
No problem. Our Rockwell Collins position is that we are not going to allow
Pbfree area array components on designs until we implement a Pbfree
soldering process. That means we either procure area array components with
Sn/Pb solderballs or we rebump (which we have developed processes for
already). Good Luck.
Dave
------------------
Thank you Dave, it will help to get this info into the hands of our
engineers so we can coordinate our efforts to avoid issues with the lead
free change...
Best regards,
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, August 09, 2005 12:41 PM
To: [log in to unmask]; [log in to unmask]
Cc: [log in to unmask]
Subject: Re: [TN] [DC] Lead-free design changes and impacts?
Hi Bill! There's nothing rocket science about the paper we published at the
CMAP conference in May at Toronto. The basic principles are that if you
subject a Pbfree solderball (BGA, CSP, FC - area array components) to a
tin/lead reflow soldering process, you have the potential of getting a very
non-uniform solder joint microstructure which can degrade the solder joint
integrity. The degradation is due to the fact that your are diffusing the
tin/lead into the Pbfree solderball instead of melting the solderball. The
severity of the degradation is going to be dependent on the level of
microstructure non-uniformity and your use environment. Additionally, ENIG
finishes appear to be more problematic than immersion tin or immersion
silver pwb surface finishes. Rockwell Collins isn't the first to document
this phenomena - there have been a number of very good papers on the topic
at several of the electronic conferences [our Rockwell photos just look
better than the photos in the other papers : - ) ]. Most of the
papers document that if you can achieve a uniform solder joint
microstructure then the solder joint integrity isn't compromised. I'll ask
Steve to post the ppt file on his website. I can send the paper out to
those folks who have an interest.
Dave Hillman
Rockwell Collins
[log in to unmask]
-------------------------------------
Ioan,
I will check with Dave Hillman on Technet and forward your comments to our
Manufacturing Engineers... since we are still planning to be using eutectic
tin/lead solder for some time we need to be conscious of that issue and
make
sure to get the BGA packages with tin/lead solder balls or we run the risks
you speak of... Thanks.
I will also notify our purchasing department that they need to watch for
any
changes to BGA packages going lead free...
Perhaps Dave will have more data he can post or send to me to help inform
us
of the potential for failures on BGA lead free packages when soldered with
Tin/lead solder.
Best regards,
Bill
-----Original Message-----
From: Tempea, Ioan [mailto:[log in to unmask]]
Sent: Tuesday, August 09, 2005 9:46 AM
To: [log in to unmask]
Subject: Re: [DC] Lead-free design changes and impacts?
Yep, big trouble.
Check with Dave Hillman on TN, he very recently wrote a paper showing what
is happening. You have a good intuition, the 2 alloys will not completely
mix giving reliability issues of which the most important is cracking at
the
interface with the PCB.
Regards,
Ioan
> -----Original Message-----
> From: DesignerCouncil [SMTP:[log in to unmask]] On Behalf Of
Brooks,Bill
> Sent: Tuesday, August 09, 2005 12:20 PM
> To: [log in to unmask]
> Subject: [DC] Lead-free design changes and impacts?
>
> There is one potential change that I really have not had time to look
into
> yet... maybe someone else has already looked at the BGA packages and
> determined whether or not the 'lead-free' solder balls under the packages
> will be an issue if you're soldering process does not go lead-free???...
> Those with RoHS exemptions will still be buying lead-free parts because
they
> can't get the tin/lead versions anymore, they will be phased out... Will
> they run into soldering problems if the lead-free solder balls don't
> collapse at eutectic solder melting temps?
>
> Best regards,
>
> Bill Brooks - KG6VVP
> PCB Design Engineer, C.I.D.+, C.I.I.
> Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
> Datron World Communications, Inc.
> _______________________________________
---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free 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 DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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
---------------------------------------------------------------------------------
|
