___________My suggestion is to use peroxide sulfuric etchant with a feed and 
bleed system based on copper content at approximately 6 oz/gal Cu.  Persulfate 
etches are very expensive to run in this mode.  Your microetch supplier should 
be able to turn you toward etch rate studies.

Regards,
Dave Sullivan
Rockwell Collins, Inc.

[log in to unmask]
__________________ Reply Separator _________________________________
Subject: GEN: Persulfate / Sulfuric Baths
Author:  [log in to unmask] at ccmgw1
Date:    12/8/96 7:44 PM


Dear Colleagues:
          
Are there any studies correlating etch rates to time / temperature / 
[Copper] /      [Sulfuric Acid] /  [Persulfate].
          
I'd like to hold a narrow etch rate window with fewer bath changes.
          
Any suggestions?
Thank you.
          
P.G. Wilson
[log in to unmask]
          
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