Influence of activated polymer on the etching rate of SiO2 in CF4 + H2 plasma

The reactive ion etching (RIE) of SiO2 in CF4 + H2 plasma is considered. The influence of activated polymer on the RIE rate of SiO2 in CF4 + H2 plasma is determined by extrapolation of experimentally measured kinetics of the etching rate. It is found that the increased surface coverage by CF2 radicals suppresses the RIE rate of SiO2 in CF4 + H2 plasma during the initial stages of the etching process. The formation of activated polymer becomes pronounced when adsorbed CF2 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 SiO2 in CF4 + H2 plasma at later stages of the etching process.