Abstract: A method of manufacturing an inter-metal level dielectric layer for a semiconductor device. The method includes forming spaced conductive lines. Next, a first conformal silicon oxide film (barrier layer) is formed over the spaced conductive lines. Gaps or valleys are between the metal lines covered by the barrier layer. A novel first “gap filling” spin-on-glass layer is formed over the first silicon oxide layer. In a critical step, the first SOG layer is heated to reflow thereby flowing all the first spin-on-glass layer from over the metal lines and leaving all of the first SOG layer in the gaps. Subsequently, a second silicon oxide layer is deposited over the first silicon oxide layer and over the first spin-on-glass layer only in the gaps. A second spin-on-glass layer is then formed over the second silicon oxide layer. An etchback is performed by etching back and removing the entire second spin on glass layer and portions the second silicon oxide layer.