The etch rates of thermally grown and CVD-deposited silicon dioxide were studied in three different reactive ion etch reactors, parallel plate, hexode and single wafer. Carbon-fluorine chemistry was used, and each reactor operated at 13.56 MHz. Assuming the etch rate to be a linear function of the DC bias and using an empirical relationship between bias and the ratio of pressure to power, a good correlation for the rate in each reactor was obtained. In addition, it was found that by plotting a normalized etch rate against the pressure to power ratio, data from all three reactors, as well as other data reported in the literature, could be correlated by a single line for each oxide.