Holly,

     You may also consider adding the following to your list :

        The elimination of Chlorine gas .

        The elimination of Silver Halide imaging film ( as a result of
        Laser Imaging .

        Improved filtration of photoresist material during the stripping
        process .


                                                    Mike Covel
                                                    Raytheon Systems Company
                                                    Tucson Az.



______________________________ Reply Separator _________________________________
Subject: [TN] switch from chromic-based etchants
Author:  "TechNet E-Mail Forum." <[log in to unmask]>, at CCGATE
Date:    6/22/98 11:31 AM


Dear Technetters:


I am writing a journal article on the environmental improvements the
industry has made over the past 20 years.  My list includes:


- reduced use of tin-lead as etch resist

- increased use of HASL alternatives

- increased use of direct metallization

- elimination of chlorinated solvents

- switch from chromic-based etchants


If any of you have any insight into the <underline>technical</underline>
reasons, the industry adopted these improvements, I would greatly
appreciate your insight and help (I really need help on the chromic acid
section).  You can respond to me directly through my e-mail address
([log in to unmask]).


Thank you in advance.

Holly Evans

Director of Environmental and Safety Programs

IPC

1400 Eye St., N.W., Suite 540

Washington, D.C. 20005-2208

phone: 202-638-6219

fax: 202-638-0145

e-mail: [log in to unmask]

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