Very interesting article. I am impressed with the thoroughness of your
testing approach and am glad to see that others share the science of
circuit manufacturing. I believe that your experiences are real and that in
your shop it happened as you say. In our shop, things went differently.

We have been using direct plate for over 5 years and I can honestly say
that we do not experience the problems you have seen. Our initial testing
uncovered wedgies when we first fired the line up, but we managed to
control the micro etch adequately and they have never reappeared. We found
the wedge voids were also related to our plasma etchback cycles, so
tweaking those played no small part. We regularly send test panels outside
for APD Oil T-shock test at Robisan Labs. Every test has passed with flying
colors and our results show absolutely no increase in resistance with
quantity of thermal cycles, unlike tests we used to get with electroless.
From time to time, perhaps once a year, will may see some voids, but
chemistry replacement does the trick. We run test panels every morning to
catch the first signs of trouble. Overall, I wouldn't go back to
electroless for anything.

We have lost no customers due to this process and have had the process
approved by IBM, Sun Micro, and everyone else as well. Sun made us modify
the Oil T-shock tests to include 012 mil vias, a practice we still follow
to this day. In general, we don't use NFP's and I am extremely interested
in your findings. I intend to run your NFP study on my process and
equipment combination.

 I would really like to see your photos and learn the name of the process.
Ours is Shadow and our equipment by ACS makes use of fluid-head technology
as opposed to sprays. Consequently, our line is shorter and faster. In
addition, we use a "diluted" chemistry solution, less than half of
recommended, to keep the coating thin. Our micro etch is "dosed" every 25
panels to keep it steady-stated, and all other aspects surrounding the
micro etch are very tightly controlled. The thin coating we obtain requires
a less aggressive micro etch to remove the carbon. In plating, we initiate
at higher ASF for a short period, then reduce to finish the plating.

Perhaps we were lucky, perhaps it wasn't luck. Our Engineering Director,
Robert Jordan, is an owner in this company. He has the power to test to his
heart's content and likes to tweak all equipment and processes. He never
buys a "drop-in" process or off-the-shelf equipment, but instead critiques
everything. Our Shadow process runs better than any electroless line I have
ever run. It is faster, easier to control,  and our boards do not fail in
the field for these types of problems.

When I have received your photos and have completed running your study in
my plant, I will certainly share our results and thoughts with you.

On another point, I truly wish the majority of TechNet was composed of
these types of articles and discussions as opposed to the 49 e-mails of
bullshit, 1 e-mail of value, that get sent every day.

At 10/3/99 12:14 PM-0400, you wrote:
>Hi everyone,
>
>For a number of reasons I did not include the photos and drawings referenced
>in the article I posted on TechNet last week.  The article describes the
>problems and defects pretty well, but I have received numerous requests for
>the photos.  I will send these out to whoever requests them over the next
>week.
>
>If you'd like to receive a copy e-mail me and I'll see to it that you receive
>them.
>
>Thanks
>
>Mark Mazzoli
>
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