So‐called ‘‘spin‐on‐Glass’’ materials (herein abbreviated as SOG) have generated a considerable amount of interest in the field of microelectronic materials and processing. The materials have been used for some time as doping sources, and have recently been investigated for use as dielectric layers, planarizing layers, RIE etch stops in multilevel lithography processes, and as final passivation layers. We report here the use of a commercially available SOG, Owens‐Illinois GR‐650 as a planarizing layer. Additionally we report a process by which this material can be converted from the as‐deposited organic polysiloxane material to an inorganic SiO2. This conversion is effected at low (≤100 °C) temperatures by an rf‐generated oxygen plasma. This process is particularly attractive for fabricating devices when the higher temperatures of plasma deposited SiO2(>250 °C) or thermally converted SOG (≊500 °C) cannot be tolerated.