Plasma etching of SiO2 contact hole using perfluoropropyl vinyl ether and perfluoroisopropyl vinyl ether.

Perfluoropropyl vinyl ether (PPVE) and perfluoroisopropyl vinyl ether (PIPVE) are used for plasma etching of SiO₂ contact holes. When etching is performed on blanket SiO₂ samples, the etch rates in the PPVE/Ar plasma are higher than those in the PIPVE/Ar plasma at all bias voltages. In contrast, when hole-pattern (100 nm in diameter) SiO₂ samples are etched, the etch rates of the SiO₂ hole in the PIPVE/Ar plasma are higher than those of the SiO₂ hole in the PPVE/Ar plasma. This can be attributed to excess production of CF₃⁺ ions in PIPVE than in PPVE, and higher contribution of physical sputtering to plasma etching in PIPVE than in PPVE. The angular dependence of the SiO₂ etch rates examined using a Faraday cage reveals that the effect of physical sputtering on the SiO₂ etching is greater in the PIPVE/Ar plasma than in the PPVE/Ar plasma. [ABSTRACT FROM AUTHOR]