We describe a method for controlling radicals in high-performance SiO2 etching of contact holes smaller than 0.1 mu m using nonperfluorocompound gases (CF3I and C2F4) in an ultrahigh-frequency (UHF) plasma. Because this method allows the independent control of polymerization and etching through the selective generation of CF2 and CF3 radicals, both high etching selectivity and a high etching rate were achieved without microloading and etching stop, even for a 0,05 mu m contact hole. Using this new gas chemistry, we achieved an optimum balance between polymerization and etching in 0.05-mu m-diameter contact holes by controlling the how ratio of C2F4/CF3I gas.