We have studied the plasma etch behavior of four different SOG materials which range from 0 to 14% in their organic content (weight percent of -CH3). A number of gas chemistries were investigated, including SF6/He, CF4/He, C2F6, and CHF3/He. Etch rates of SOG films were determined relative to that of thermal SiO2 as a function of the partial pressure of the fluorine-containing gases. In general, at low partial pressures of the etch gas, where no polymer formation occurs, the SOG films etch faster than thermal oxide. Also, the etch rates increase with an increase in the overall organic content (Si-CH3) of the SOG. While higher SOG etch rates relative to that of thermal SiO2 are attributable to the lower SOG densities, the increase in SOG etch rates with increasing Si-CH3 content probably reflects the effect of decreasing Si-O bond density. Under conditions favoring polymer formation, the SOG etch rates are suppressed relative to that of oxide indicating enhanced polymerization rates on a siloxane SOG surface. Preliminary data obtained using gas chemistries with high F/C ratios suggest that the relative contributuion by F atoms to etching is larger in a siloxane SOG than in SiO2.