Abstract: A planar deep oxide isolation process for providing deep wide silicon dioxide filled trenches in the planar surface of a silicon semiconductor substrate, said process comprising the steps:(a) forming deep wide trenches in the planar surface of the silicon substrate;(b) forming a thin layer of silicon dioxide on the planar surface of the silicon substrate and the exposed silicon surfaces of said deep wide trenches;(c) applying resin glass (polysiloxane) to the planar surface of said semiconductor substrate and within said deep wide trenches;(d) spinning off at least a portion of the resin glass on the planar surface of the substrate;(e) baking the substrate at a low temperature;(f) exposing the resin glass contained within the deep wide trenches of substrate to the energy of an E-beam;(g) developing the resin glass contained on said substrate in a solvent;(h) heating said substrate in oxygen to convert said resin glass contained within said deep wide trenches to silicon dioxide;(i) depositing a layer of silico