Can't say how many times I have used & enjoyed Steve's web site to see pics
first hand.

If the results are so predictable, I would raise the NOTE off the PO &
engrain it right onto the FAB DRAWING notes section itself for this specific
PCB. That way the FAB house should really be aware of what NOT to use.

Your note should be OK as we have all done it but sometimes, the FAB house
is busy/rushing or whatever & will miss it.
Now who pays for it ??? We don't enjoy getting into a spitting match with
our vendors.

Regards
TDK





-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stephen Gregory
Sent: Tuesday, May 17, 2005 10:28 AM
To: [log in to unmask]
Subject: [TN] Bubbly, flaking, soldermask...


Hi All...

Boy, I hope your day is going better than mine...

One of my inspectors called me to to look at an assembly she had. I came to
her station and started looking at the assembly, and just about cried (not
really). I observed something that I've seen before...

The solder mask is losing adhesion from all copper features, traces, vias,
everything copper. This starts occuring after about 2-3 wash cycles in our
batch cleaner. Take a look at; "Mask Bubble, Mask Bubble 2, 3, and 4", at:
http://www.stevezeva.homestead.com

I've seen this before and thought we had the problem taken care of. It's
caused by the chemistry we use to clean RMA flux residues, not being
compatible with certain dryfilm solder masks. We use Kyzen Aquanox 4512P in
the manufacturers recommended concentration, and we see this problem
everytime a Dynachem Dynamask (now Shipley) dry film is used. We used to use
Aquanox XJN and had the same problem.

On our PO's we have a note that when dry film solder mask is called out on
the fab drawing, use Dupont Vacrel series dry films, as we know that we have
absolutely no problem with Vacrel.

The last time I had this problem and posted about it, there were a few
responses that I shouldn't be having these problems, that the Dynachem
Dynamask dry films are very robust. But I swear, everytime I see the mask
bubbling and flaking like you see in the images I've posted, it turns out
that a Dynachem dry film was used.

Can I be the only one that has these probelms?

Kind regards,

-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
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If you are not the intended recipient, you may not copy, use or deliver this
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