Edward, I agree with Mr. Gregory of Atotech that there should be no
reason that you cannot process FR-4 materials and polyimide with the
same reduced brown oxide.  The only material that I have been unable to
use with reduced oxide is cyanate ester.

I have had very poor success using conductivity control for these types
of rinses.  I also strongly recommend against using DI water for rinsing
following DMAB - I have seen problems with yellowish staining of the
reduced oxide when using DI.  I have had my best success using a pH
controlled rinse of between 3 and 4 pH units following the oxide; this
scavenges the chlorite from the oxide deposit as well as removing the
hydroxide from the surface.  This chlorite will destabilize the very
expensive DMAB; using a pH controlled rinse can reduce consumption of
the DMAB by a very large amount.  Following the DMAB I have sometimes
used a pH controller to maintain the rinse tank below 7 pH, and once
again have ALWAYS used soft or tap water for this rinsing.

Good luck
Fred J.

In case you didn't catch it the first two times, I NEVER USE DI WATER
FOR RINSING AFTER THE DMAB!!!!

>>> "Eltek Ltd. - Process Engineering"
<[log in to unmask]> 02/11/98 10:40am >>>
Hi Technetters !
Our black/brown oxide line is operating with baskets . The final sequence
of
black oxide process include :
black oxide , cascade rinse with DI water , DMAB reducer , cascade
rinse
with DI water , static DI hot water , dryer .
 The final sequence of brown oxide process include :
brown oxide , cascade rinse with DI water ,  , static DI hot water , dryer .
We are planning to regulate DI water replenishment in flowing rinses and
static hot water rinse by conductivity control .
What values of conductivity should be considered ?
All comments will be appreciated
Regards

Edward Szpruch
Eltek Ltd - Israel
Tel  972 3 9395050
Fax 972 3 9309581
E-mail :  [log in to unmask]

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