There as been many an occasion debris or foreign
matter in a via causing problems.
I personally mask over all vias, and have never had
a problem, but have a question.
Yes, debris in a via and being under a pad, in
encapsulated in solder or plating etc.
is a reasonable question to ask. Could there be a
problem, but my question is;
Isn't this a cleanliness issue?
Is it just a fact that regardless of the
manufacturer that debris or such is a fact and not
just a manufacturer issue.
Is it that, yes it may be just a manufacturer
issue, but there is no accountability
before assembly and we can't just count on the
board to be clean.
Or is it the time between manufacturing and
assembly that we have to worry about
debris?
I've never had an issue with debris in a via, and I
don't know if I have good manufacturers
or that my traces/circuits have never been that
critical.
----- Original Message -----
Sent: Friday, October 24, 2003 9:30
AM
Subject: [TN] Cleaning of via holes under
components
Hello,
One of our Design Engineers is designing a
surface mount PCB
assembly and would prefer not to have the via holes
solder mask
tented. However, he is concerned that, if he does not
call up
solder mask tenting on his bare PCB drawing, foreign matter
could
find its way into a via hole and, if a component (e.g. an IC)
was
mounted over the via hole, the foreign matter might not be
removed
during the cleaning process.
Has anyone had experience with
this situation? I would appreciate
any help you could give
me.
Thanks very much in advance.
Paul Baine
Q.A.
Manager
C-Tech Ltd.
Cornwall, Ontario,
Canada
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