Ashok,
The blistering that Graham Naisbitt describes is also sometimes called
mealing.  If you do literature searches, especially in military-related
areas, you may find more information with that key word.

While I am on the subject, when you ask about what criteria to use in judging
a fabricator, let me throw my 2 cents worth in regarding board cleanliness.

You should find out from the fabricator how they quantify their board
cleanliness.

Do they do Bellcore SIR?  How often and what are the results for both bare
copper and after HASL?

Do they do ionic cleanliness testing?  With what instruments?  How often?
 What are the average results?  More importantly, have they ever done any
other testing or correlation studies to determine if the bulk ionic
cleanliness testers have an adequate measure of bare board cleanliness?  This
might mean a correlation study with either SIR or ion chromatography or HPLC.

One thing you might ask is if the fabricator can meet Delco Electronics
C-7000 bare board cleanliness specification.  This spec is based on ion
chromatography and is a far superior measure of bare board cleanliness than
is simple bulk ionics.

In my view, a fabricator who is really on the ball has a base ion
chromatography study done in parallel with a bulk ionic study to determine a
process control limit, and does periodic monitoring with ion chromatography.

For what it worth.

Doug Pauls
CSL

Just say:
My opinions are worth every penny you pay for them.

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