Plasma polymerized hexamethyldisiloxane thin films were produced using an electrode capacitively coupled apparatus. Fourier transform infrared spectroscopy analysis indicated that the thin film spectra are composed not only of the corresponding monomer bands but also of several new bands. Auger electron spectroscopy analysis indicated that the permeation depth of aluminum into the films is ca. 30 nm when top electrode is deposited by evaporation aluminum. The increase of relative dielectric constant and decrease of dielectric loss tangent with the discharge power is originated from high cross-link of the films.