Hi Rob,
Many people, concerned with ionic contamination, have been asking this
age-old question. The difficulty (at least from my perspective) is that
there is no one-size-fits-all pass/fail limit. Ideally, each company who
manufactures should try to determine their own pass/fail limits. What
Company A finds as acceptable for their manufacturing environment/s may be
something different for Company B. Another consideration is that as
technology becomes denser and more sophisticated, then the amounts of
allowable ionics will likely change as well. The industry has been working
on this for as long as I have been involved and have not really been able to
establish pass/fail limits as it were. This is likely because of all the
different materials that are used and all of the variations in manufacturing
environments. To set these limits is to say the least, an ominous
undertaking. The best we have to date are guidelines to aid in deciphering
the levels of ionics that have been known to cause problems. The habitual
"bad actors" in the manufacturing theater are: Cl, Br, SO4, and the various
weak organic acids (WOA's) used in many of the flux and paste packages. The
industry is continuing to work on this issue, but no new updates (that I am
aware of) as of yet. You might try looking at IPC-HDBK-001 to get a sense
of current limits and it is a good guide.
I hope this helps. If you would like to discuss this further, please
contact me offline.
Best Regards,
Joe Russeau
Process Analyst
Precision Analytical Laboratory, Inc.
4106 Cartwright Dr. Ste. A
Kokomo, IN 46902
P: 765-455-1993
F: 765-455-1996
E: [log in to unmask]
----- Original Message -----
From: "Robert Coburn" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, April 08, 2005 10:18 AM
Subject: [TN] Ionic contamination / specific ion / limits
> Hi T'Netter's;
> Has there been any update regarding the acceptable limits for ionic
> contamination, particularly for specific ions?
> Most frequently referenced by our end-users is the ROSE test or its
> automated equivalent (Omegameter, Ionograph, etc).
> Any update is appreciated.
> TIA.
> Regards,
> Rob
>
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Search the archives of previous posts at: http://listserv.ipc.org/archives
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