Scott, adding acid to your slurry is not a bad idea but be careful about equipment compatibility.
You may find metal parts, especially welds, rusting.  We add 250cc of Phosphoric to our IS Pumex 
slurry each shift to the same end with good results.

With respect to UV bumping, I have always believed the purpose of the bump was to harden the 
surface of the LPI to prevent flux absorption which ruins ionics.  Doing it after HAL is kind of
counter-productive.

----------
From:  Scott B. Westheimer[SMTP:[log in to unmask]]
Sent:  Wednesday, May 14, 1997 5:09 PM
To:  [log in to unmask]; [log in to unmask]
Subject:  FAB

From: Scott Westheimer
Date: 5/14/97

Recently we encountered a problem with adhesion of the S/M during HAL. We
use Giba's S/M and due to some problems we have to processing boards
through HAL several times to get all of the areas covered with solder. We
tried several things to try to improve the adhesion and have found two that
seem to work well. A 3% H2SO4 dip prior to ALO3 scrub and skipping the UV
bump until after HAL have given us excellent results. Our QA department has
concerns about the properties of the S/M with UV bumping after HAL and I
was wondering if any has tried this approach and if they have found any
problems with doing this. Also we are considering putting the H2SO4
directly in the ALO3. Any comments?

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