Photoresist damage and patterned feature distortions generated in reactive ion etch (RIE) processing of SiO2 thin films were studied as a function of the applied radio frequency power density in two RIE reactors. The photoresist damage was found to originate from plasma- and thermal-induced phenomena that characterize the etching plasma. The onset of photoresist damage was correlated to the glass transition temperature (T-g) of the thermal-cured photoresist. T-g was found to be 116 +/- 8 degrees C for the AZ P4330 positive photoresist and correlated with an onset radio frequency power density of 2.7 +/- 0.2 W/cm(2). Below T-g, the plasma-induced phenomena manifested as photoresist etching, hazing, and creep. Above the T-g of the photoresist, thermal-induced phenomena, manifested as severe photoresist degradation and creep, was found to be the dominant mechanism for the photoresist damage. A model is also presented that predicts and explains the photoresist behavior in an RIE environment with respect to the T-g of the photoresist and as a function of the applied radio frequency power density.