The effects of the postplasma treatment on the dielectric properties and reliability of F-doped silicon oxide (SiOF) thin films were investigated. The postplasma treatment of the SiOF films was carried in terms of plasma treated radio frequency (rf) bias power. As the plasma treated rf bias power increased, the chemical properties of plasma treated SiOF films tended to resemble those of thermal oxide as a result of both the reduction of the Si-F bond in the films and the increment of film density. The density of the film varied with the applied rf bias power; 1.927 g/cm(3) for 0 W and 2.113 g/cm(3) for 150 W, which were lower than those of-the thermally grown silicon oxide by about 15% and 7%, respectively. As the plasma treated rf bias power increased, increases in both dielectric constant from 3.14 to 3.43 and the breakdown field strength from 3.5 to 8 MV/cm were determined for the postplasma treated SiOF films. Fourier transform infrared results also showed the intensity reduction of both the H-OH peak at about 3400 cm(-1) and the Si-OH peak at about 3650 cm(-1) with increasing the rf bias power. Therefore, both surface oxidation and densification resulting from O-2 plasma treatment seemed to play a major role in making the SiOF films a very attractive material for ultralarge scale integrated intermetal dielectrics.