Intermetal Dielectric Gap Fill by Plasma Enhanced Chemical Vapor Deposited Fluorine-Doped Silicon Dioxide Films

Fluorine-doped tetra-ethoxy-ortho-silicate (F-TEOS) silicon dioxide films were deposited using a dual frequency multi-station sequential plasma enhanced chemical vapor deposition (PECVD) system. F-TEOS films with various Si–F content were deposited using mixture of vaporized TEOS, O2 and C2F6. The Si–F content and gap filling capability of F-TEOS films was investigated under various deposition conditions. The gap filling capability was found to be dependent upon wafer temperature, pressure and gas phase reactant concentrations, but is predominantly dependent on Si–F content. Aspect ratios (AR: height of metal lines versus spacing between metal lines) up to 1.35:1 with 0.25 µm spacing were filled with no observable seams and voids.