Effects of radio frequency bias frequency and radio frequency bias pulsingon SiO2 feature etching in inductively coupled fluorocarbon plasmas

The effect of radio frequency (rf) bias frequency on SiO2 feature etching u sing inductively coupled fluorocarbon plasmas is investigated. It is found that the rf bias frequency can have an important effect on SiO2 feature etc h rate, microtrenching phenomena, and SiO2-to-photoresist etch selectivity. In addition, the effect of rf bias pulsing on inductively coupled fluoroca rbon plasma SiO2 etching has been studied and a model that describes the da ta well is presented. The model assumes that fluorocarbon deposition occurs while the rf bias is off, fluorocatbon etching occurs during the first par t of time that the bias is on, and substrate etching occurs once the fluoro carbon material has been removed from the substrate. (C) 2000 American Vacu um Society. [S0734-211X(00)02702-5].