A method is disclosed for forming insulative inter metal dielectric (IMD) layers without the attendant problems of having voids, key-holes and air gaps. This is accomplished by reducing the aspect ratio of the gaps between metal lines through a judicious two-step dielectric filling process and through the use of two-step removal of the photoresist. That is, the gap is filled with photoresist first, and then partially removed, thereby leaving a portion in the gap to reduce the aspect ratio of the gap. When a second insulative layer is formed over the substrate, the gap between the metal lines is filled without the conventional attendant problem of forming voids or key-holes. Hence, void free IMD integration with improved IMD gap filling is achieved along with improved IMD thermal conductivity through the use of a metal liner.