Hi Steve & other Technetters,

From all the uncoated boards of this batch we have removed a component
to see which state the soldermask is in. 50% was very bad, the other 50%
has the problem just a little bit on the outer edges of the
solderresist. All of these are from one single datecode of bare boards,
other datecodes are perfect. That's why we expect that 50% of the coated
boards have the same issue.
A question that I have is how bad it actually is to have this quality
of soldermask (it has lost adherence and is flaking off) when the boards
are parylene coated. Any opinions on this?

Daan

B.T.W.  I searched the Technet archives for "Dynamask" and all subjects
that I found were about flaking of soldermask. Nice mask this is!




>>> <[log in to unmask]> 11/22/04 11:59pm >>>

Hi Daan!

I'm sorry, I can't give you any ideas of how you'll be able to inspect

beneath the components reliably for the integrity of the soldermask.

I do have a couple of questions, how do you know it's only 50% of the

boards? To me, if you have that high of a percentage of boards that
have the  issue,
I would be suspect of them all. Do you know what the cause is of the
mask
flaking?

I have had my soldermask issues, and all of them without question have

occured with dry films. I have had Dynachem (now Shipley) 5040 flake
from  all the
copper surfaces. This was because it doesn't hold up well against the
Kyzen
Aquanox that we use to clean our assemblies. I've posted a couple of
times  to
the Technet when this has happened to me.

What do you use to clean your assemblies with?

Sorry couldn't have of more help...

-Steve Gregory-

Hi  Technet,

I have a problem with  a batch of boards of which I know  that an
estimated 50% of them have a problem with the soldermask. The  mask
(Dynamask 5040 dry film) is flaking off the board, and we didn't
notice
this because the mask is only applied underneath the components (and
all
of them have a low standoff, which makes it impossible to  inspect).
Now we need to  know which of the boards are affected, but
desoldering
some of the parts to take a peek is not an attractive option as  these
boards are already parylene coated.

I'm quite convinced that  the answer is "no", but still I'd like to
give
it a try and ask the  following question:
Does there exists ANY technology (non-destructive) that  makes it
possible to inspect the quality of the soldermask underneath
components?

Best regards,

Daan Terstegge
PCB Assembly  Department
Thales Land & Joint Systems

Tel       +31(0)35 524 8297
Fax       +31(0)35 524  8181
[log in to unmask]
Unclassified  Email

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