An interlevel dielectric layer, such as a silicon oxide layer, is selectively etched using a plasma etch chemistry including a silicon species and a halide species and also preferably a carbon species and an oxygen species. The silicon species can be generated from a silicon compound, such as SixMyHz, where “Si” is silicon, “M” is one or more halogens, “H” is hydrogen and x≧1, y≧0 and z≧0. The carbon species can be generated from a carbon compound, such as CαMβHγ, where “C” is carbon, “M” is one or more halogens, “H” is hydrogen, and α≧1, β≧0 and γ≧0. The oxygen species can be generated from an oxygen compound, such as O2, which can react with carbon to form a volatile compound.