Steve,
We've seen samples such as you describe from a customer. About
a year ago they had a couple boards that had
lifted pads at the copper. Through our analysis we learned
this was the plated copper lifting from the
copper foil/e-copper layer.
Not sure if this is what your seeing, perhaps a photo would
help. You can send me one, I'll toss it
around the shop here.
We learned that there was actually a fingerprint of all things
directly under this defect. Needless to
say we discontinued allowing the eating of potato chips in our
wet process area.
Franklin D Asbell
Hi ya'll!
Here's something weird I've never
come across, but maybe some of you have. We
built this Hi-Rel board here that
the PCB drawing calls out for 2-ounce
copper.
The board has this
leaded SMT multi-capacitor part (it's like 3 huge ceramic
capacitors stacked
on top of each other) and has 8-leads. After assembly, and
before we test
then conformal coat it, we put the assembly on this vibration
table to go
through some ESS.
There's been a few of these capacitor deals come loose
because they're so top
heavy, but that's a whole 'nuther issue...
What
we've been seeing on some of these boards, is that either the pad
completely
lets go from the laminate (it's a polyimide), or sometimes we'll
see the pad
come up in what looks like a layer of copper, yet there's still
copper down
on the PCB...as if the copper has split horizontally in two
distinct layers?
Is this possible? Does 2-ounce copper clad laminate get the
copper plated an
ounce at a time? Is this a defect? I've never seen something
like this
before, and I can take a picture and send it to ya' if you want
me
to....
Thanks!
-Steve
Gregory-
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