Steve,
It's my experience that, although dry film doesn't have the best adhesion in
the world, you should still expect it to stay put in most solder and
cleaning processes. The only time I've had a real problem is when I've used
"spot mask" liquid latex rubber prior to wavesolder. The ammonia in the spot
mask diffuses through the resist and attacks the copper causing resist
blistering. Potential solutions are to use a non-ammoniated mask or try
different types of resist. Vacrel works well.

Bryan
Alenia Marconi Scotland
----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, August 25, 1999 10:27 PM
Subject: [TN] Dry Film Soldermask Adhesion..


> Hi Ya'll!
>
> I've had one of our buyers come to me with a problem that we have with one
of
> the fabs we buy.
> I'm no expert on fabs by a long shot, but I told him know where to ask (am
I
> kissing-up enough? Hehehe...)
>
> Problem is with a fab (GFG laminate) that our customer is specifying dry
> film...they want to ensure the via's
> are tented. There isn't a brand specified, but they do want the fab masked
in
> accordance with IPC-SM-840 Class-3
> Type B dry film. Our fab vendor has chosen to use a Dynachem dry film. The
> problem we're having is that the mask is
> flaking from the bare copper. The fab vendor is suggesting that our
cleaning
> chemistry may be causing the problem.
> We're using Aquanox XJN in a MCS-1000 Electrovert cleaner. The wash
> temperature is 140 F., and my rinse is 120 F.
>
> Know what might be causing this? Do you recommend any other brand dry
film?
>
> Thanks!
>
> -Steve Gregory-
>
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