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 produce low dielectric constant (k) SiO/sub 2/ films for high quality interlayer dielectrics. The SiO/sub 2/ films are fluorine-doped/carbon-doped by PII with CF/sub 4/ plasma in an inductively-coupled plasma (ICP) reactor. It is found that the use of CF/sub 4/ doping results in exceptional dielectric properties which differ significantly from fluorinated SiO/sub 2/. The dielectric constant of the SiO/sub 2/ film is reduced from 4.1 to 3.5 after 5 minute PII, other electrical parameters such as bulk resistivity and dielectric breakdown strength are also improved.