Method of making an interconnect structure with an integrated low density dielectric

A method of constructing a semiconductor device comprising:

• providing a layer of patterned conductors formed on a semiconductor substrate;
• depositing and gelling a layer of a precursor solution on said substrate, thereby forming a wet gel layer having porous structure;
• drying said wet gel layer without substantial densification of said porous structure, thereby forming a porous dielectric layer filling gaps between and covering said patterned conductors, said porous dielectric layer having a dielectric constant of less than 3.0, a porosity between 30% and 95%, and an average pore diameter of less than 80 nm;
• removing a top portion of said porous dielectric layer;
• and
• depositing a non-porous dielectric layer over said conductors and said porous dielectric layer to complete an interlayer dielectric, whereby the capacitive coupling between conductors on the same level is substantially reduced compared to a solid silicon dioxide dielectric and the mechanical properties of said interlayer dielectric are essentially the same as that of non-porous silicon dioxide.