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January 1999

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Subject:
From:
"Nelson, John" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 8 Jan 1999 09:51:01 -0500
Content-Type:
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text/plain (28 lines)
When I image a board using nickel/gold as an etch resist on part of the
panel
and solder as an etch resist on another area, when I etch in alkaline etch
the
copper near the solder area etches much slower than the copper near the
nickel
gold.  The electropotentials of the metals are different enough to explain
the
differences in etch rate.

My question is this; when we use tin as an etch resist we seem to get much
more
undercut than when we use solder as an etch resist.  Can this difference in
copper
etch rate be explained the same way?

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