Special feature: Cleaning chemistry vs. mechanical impingement
The panel
Trevor Galbraith Michael Konrad Steve Stach Dr. Harald Wack
Editor-in-Chief, Global President, Aqueous President, Austin President, ZESTRON
SMT & Packaging Technologies American Technologies Panelist
Moderator Panelist Panelist
chromatography, but the price normally solubilization of residues on the surface. what the soubilizing liquid (i.e. IPA and
precludes its use in daily production test- New tests methods are currently developed water) really solubilizes. Because if nothing
ing. ROSE testers (Ionograph, Zero Ion, to improve the current situation. One solubilizes, what do the numbers really tell
Omegameter) are most commonly used. interesting one we have seen great success you?
with is the rosin and the flux test. These
Wack: Best case is to remove all residues
are analytical tests that probe the slightest
Steve Stach, Austin American Tech-
to allow for good conformal coating results
presence of residues and expose them visu-
nologies: A ROSE test must dissolve the
or wire bonding, meaning subsequent
ally to the user. This means the user can
residues in order to make an accurate
processes that require very clean surfaces.
actually see if residue is left, or also verify
measurement.
Some of the tests I have described—ionic
the low readings he received from ionic
contamination test, IPC/water, or the
contamination measurements.
Wack: Not necessarily. I would simply
ROSE test (including the modified)
suggest to have complimentary tests in ad-
ROSE test—are intended to solubilize the Question from Mike_UPMG: What’s
dition to the ROSE test.
residues. Unfortunately the IPC standard your take on the capabilities and shortcom-
does not allow to capture the new, emerged ings of the Omegameter?
Galbraith: Does this mean that most
challenges with this test. When it was
vendors should send every job that needs
introduced decades ago, it was intended to
Wack: As stated before it’s a very useful
to be cleaned to their chemistry vendor or
measure cleanliness for RMA-based fluxes.
tool and established tool, but the solu-
a local lab?
Nowadays, no-clean fluxes are not being
bilization cannot be 100% guaranteed,
touched by IPA, which means any remain-
especially for no-clean flux residues.
Konrad: Random lot testing is normally
recommended. ROSE testers are used in-
ing residue, which is subjected to the ionic
contamination measurement, will not be
Konrad: These ROSE testers average test
house. IC testing is normally sent to a lab.
solubilized or fully detected. This leads to
results over the entire area. Use them
false readings and a feeling of cleanliness.
cautiously. They are excellent tools but
Wack: There has also been discussion on
Unfortunately, the user is misled in believ-
do not rely on a “high pass.” Additional
improved methods, but they are not yet at
ing his assemblies are actually clean. Ion
testing (IC) may be required. ROSE testers
a beta site level. Maybe in a few months
chromatography: better method as it offers
utilizing dynamic technology as opposed to
from now.
more data on the nature of the residues.
static are better at detecting weak no-clean
Galbraith: How far does the current
However, it also uses IPA and water for
ions.
IPC-CH-65 Standard go towards meeting
extraction, which in turn also limits the
Wack: In general it’s important to ask
cleanliness requirements, and could it be
improved?
www.globalsmt.net Global SMT & Packaging – May 2009 – 27
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