Document Type


Date of Award

Fall 1-31-1997

Degree Name

Master of Science in Engineering Science- (M.S.)


Committee for the Interdisciplinary Program in Materials Science and Engineering

First Advisor

Roland A. Levy

Second Advisor

Lev N. Krasnoperov

Third Advisor

Vladimir Zaitsev


Trifluoroiodomethane (CF3I), a non-global warming gas, has been investigated with study as a substitute for typical CFC etchants, such as CF4 and C2F6, used in wafer pattering technology. This investigation was carried out by exposing dielectric films of silicon oxide (SiO2) and silicon nitride (Si3N4) in CF3I and C2F6/O2 (used as a reference) plasma environments. The etch rate of these films was ascertained as function of applied rf power, etchant gas flow rate, reaction chamber operating pressure, and O2 to CF3I ratio.

Upon increasing power, the etch rates of SiO2 and Si3N4 by both CF3I and C2F6/O2 were increased. The study of flow rate showed various results depending on types of etchants and dielectric film materials. According to the processing conditions, there were two limits in etching with CF3I. First, at the pressure higher than 50 mTorr, etching of' Si3N4 can produce polymer film on sample surface. Secondly, at O2/CF3I ratio higher than 0.17, etching of both dielectric films can result in generating reddish particles all over the sample and the reaction chamber side wall.