Emily,
        I apologise as I didn't see your original question. However a
realtime quality of etching I should think would be actual product
measurements. Use a scope or other calibrated instrument to tell you if you
are meeting the product spec after etch. Use SPC with this data. Most
etchants as I see it are controlled fairly well with current controllers.
There will be variation in the pH, Cu conc. etc. but nothing wild unless you
have problems. The bottom line is the product. Are you getting what you
should.

Mike Doty

-----Original Message-----
From: Emily Tse [mailto:[log in to unmask]]
Sent: Sunday, March 11, 2001 10:04 PM
To: [log in to unmask]
Subject: [TN] Quality of Etching


Dear All,

First of all, thanks for those who'd replied, it sure gave us some hints on
some of the methods that are used for quality checking on etching process.

For the quality of etching process, many of you have suggested cross section
analysis and surface analysis such as SEM/EDX. One of the other suggestions
is a passive way analysis on the quality of etching by evaluating the
chemical properties (such as the Cu concentration) of etchant after the
etching process.

All of the above are some good ways to start, yet we wonder if there's any
"real time" analysis on the etching quality?  We're looking for some method
that is simple enough to be carried out on the production floor, while
actively controlled the etching process (instead of using the quality of the
etchant AFTER the etching process)

Any ideas?

Looking forward for your reply!

Sincerely,
Emily Tse


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