Dear all,

        I have another question regarding plasma etching (please see
email "Subject: post-RIE photoresist residue" for the other question).
Besides, CF4, CHF3, C2F6, and other fluorine-contained plasmas, Cl- and
Br-contained plasmas, such as CF3Cl and HBr, are commonly used for
dry etching. However, are they very toxic and need special chamber, pump,
and safety conditions to use those gases for dry etching? The thin film
materials for etching are amorphous silicon, amorphous silicon nitride,
molybdenum, and (maybe) chromium. Any comments are appreciated.


Isaac