The reactive ion etching (RIE) of SiO 2 in CF 4 + H 2 plasma is considered. The influence of activated polymer on the RIE rate of SiO 2 in CF 4 + H 2 plasma is determined by extrapolation of experimentally measured kinetics of the etching rate. It is found that the increased surface coverage by CF 2 radicals suppresses the RIE rate of SiO 2 in CF 4 + H 2 plasma during the initial stages of the etching process. The formation of activated polymer becomes pronounced when adsorbed CF 2 radicals are slowly activated. The activated polymer intensifies the etching reaction and enhances the etching rate. At the same time, the activated polymer intensifies the polymerization reactions. The increased surface coverage by the polymer suppresses the RIE rate of SiO 2 in CF 4 + H 2 plasma at later stages of the etching process.