FABRICATION OF LOW DIELECTRIC-CONSTANT MATERIALS FOR ULSI MULTILEVEL INTERCONNECTION BY PLASMA ION-IMPLANTATION

High dose-rate plasma ion implantation (PII) has been utilized to prod uce low dielectric constant (k) SiO2 films for high quality interlayer dielectrics. The SiO2 films are fluorine-doped/carbon-doped by PII wi th CF4 plasma in an inductively-coupled plasma (ICP) reactor. It is fo und that the use of CF4 doping results in exceptional dielectric prope rties which differ significantly from fluorinated SiO2. The dielectric constant of the SiO2 film is reduced from 4.1 to 3.5 after 5 minute P II. Other electrical parameters such as bulk resistivity and dielectri c breakdown strength are also improved.