Low-dielectric constant SiO(F.C) films for ULSI interconnections prepared by CF_4 plasma ion implantation

摘要

Plasma ion implantation (PII) doping technique has been utilized to prepare a new low-dielectric constant (low k) material SiO)F,C). Fluorine and carbon were implanted into SiO_2 films by CF_4 PII using an ICP plasma reactor. The effective dielectric constant of the films was significantly reduced after PII doping. An analysis of a double layer model indicated that a high quality dielectric layer with a dielectric constant down to 2.8 can be achieved by an optimized PII process. Contrasting to other coventional low-k material techniques, PII process also improved bulk resistivity and electrical field breakdown strength. The improvement possibly resulted from adding carbon into the films. The etching effect of CF_4 PII could be beneficial to planarization and gap filling of dielectric interlayer.