Porous amorphous fluoropolymer films with ultralow dielectric constant

With the development of ultralarge scale integrated circuit, new interlayer dielectrics with low dielectric constant for multilevel interconnections a re required, instead of conventional SiO2 films. For the sake of seeking pe rfect dielectrics, amorphous fluoropolymer (AF) thin him with a thickness o f about 0.9 mu m has been prepared by spin-coating method, following the pr inciple of phase separation. By capacitance-voltage (C-V) measurements the dielectric constant of the thin film is equal to 1.57 at 1 MHz, which is at tributed to numerous pores contained in the film matrix. X-ray photoelectro n spectroscopy (XPS) spectra show that after annealing, about 71% CF3 group s in the AF film have decomposed into CF2, CF, etc. This leads to the incre ase of CF2 groups by three times and CF groups by 8% in the AF film. In a w ord, compared with the film without being annealed, about 25% carbon, 7% fl uorine and 12% oxygen atoms will be lost after annealing at 400 degrees C f or 30min.