Abstract: A process for chemically modifying spin-on-glass (SOG) for improved performance in semiconductor device fabrication is disclosed. To compensate for severe surface topographies associated with very large scale integration (VLSI) technology, a thicker non-etch back SOG process is utilized for forming a SOG layer over a chemical vapor deposition (CVD) layer. A single layer of SOG is formed over the CVD layer, providing planarizing coverage over formational or growth defects. The silylation of the SOG layer provides for the formation thicker single layers of SOG and significantly reduces the wet etching rate in diluted HF.