Fred,

I must agree with Jerry Sallo. I have tried this method you speak of.  I have never been able to  etch off the copper that uniform. Typically I would end up just creating more problems when I tried to etch the plated product. I have found that, as Jerry indicated,  you would end up having to over etch the panel anyway and you will find your line widths varying on the same circuit.  I'm not sure of your reasons but I suspect your faced with having to deal with some very tight lines and spacings. I would recommend using the cap sheet or carrier sheet  foil as well. Just my thoughts.

Ed Cosper
Director Quality Assurance and Engineering
Graphic Electronics Inc.
Tulsa, OK 

----------
From:  Fred Johnson[SMTP:[log in to unmask]]
Sent:  Monday, March 23, 1998 2:03 PM
To:  [log in to unmask]
Subject:  [TN] copper etching

Hello all;
I would be interested in hearing any comments about etching down 1oz.
copper foil to 1/4 oz or 3/8 oz.  It is our understanding that this requires a
specific equipment set to control the uniformity of the thickness across
the panel surface; it is also our understanding that chemical control is
very important (although I am not sure what types of chemistry may used
for this process, i.e. cupric, sulfuric/peroxide, etc.).

Any suggestions for equipment and chemistries would be appreciated.

Regards,
Fred Johnson
JMSPI

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