I didn't mean to imply that the Aquanox XJN caused the problem. We've used
XJN here for years, without an issue...except with Dynachem Dynamask, now
Shipley, since they've bought that line from Dynachem.

The current issue with the assembly that I've posted pictures of, is with
both sides, not just the bottom side. The copper beneath the mask that is peeling
off, is as shiney as a new penny...which tells me that the surface wasn't
prepped as it should have been, based on the inputs from our esteemed group.

This is the first time I've ever experienced this particular problem...this
is with a very well known fab vendor.

As I said in previous posts, the mask seems fine, it just didn't stick to the
copper. We're pursuing this issue with our fab vendor.

When things happen like this, I always ponder; "Why me?" This was a $3500
assembly.

-Steve Gregory-
Hi Bill how do you like CO? Ft. Collins is a nice area. Probably warmer
there right now then here in NH. Actually they said that it is warmer at the
S.Pole then in NH right now!

In regards to the solder mask issue. Steve has seen these types of problems
in the past.
Flaking, white & gray stains etc. Once I believe there was a problem on only
25 boards from a lot of a few hundred.
A quick search of the TN archives will confirm. I believe the root cause is
usually traced to the board level fab.
Your input on test methods etc. is all great info. How many CM's and OEMs
actually know of this being performed or monitored at their board suppliers?
Perhaps a work shop at an IPC event should be in the works?

Aquanox XJN and XJN+ products are in use successfully in many companies and
facilities. The majority being defense and space related.
This surely covers the range of popular solder masks in use today.
In addition XJN has been tested for compatibility at a major UK supplier.
This test proves that a successful UV bump is needed to avoid any
delaminating. Even with only HOT water applied.
The wash process at LaBarge has only exposed the defect from the solder mask
application.
A related thread shows similar problems with an nPb product at use in
Singapore. With the boil temp around 160F, past testing has shown that
solder masks defects such as white/gray staining etc. usually spring up when
wash temps of aqueous and vapor products approach this range. A secondary UV
bump can usually eliminate this.
Not to say that all dry and LPI masks are chemically compatible. There has
on rare occasion been one or two that has surfaced but it has been many,
many years since I have seen a true incompatible issue surface.
Steve, please call or keep me posted on the current issue.
Bill take care, hope all is well on the home front.

Sincerely,

Charlie Pitarys
Director of Application Technologies
603.622.2900 X-115

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