A
plasma-assisted deposition
system for carrying out a
plasma-assisted deposition method has a
processing vessel defining a
vacuum chamber and having an open upper end, a
dielectric member covering the open upper end of the
processing vessel, and a flat antenna member placed on the upper surface of the
dielectric member. A coaxial
waveguide has one end connected to the upper surface of the flat antenna member and the other end connected to a
microwave generator. The flat antenna member is provided with many slots of a length corresponding to half the
wavelength of a
microwave arranged on concentric circles. For example, a circularly polarized
microwave is radiated from the slots into a
processing space to produce a source
gas plasma.
Electron temperature in the
plasma in terms of
mean square velocity is 3 eV or below and the
electron density in the plasma is 5×1011 electrons per cubic
centimeter or above. The plasma is used for depositing a
fluorine-containing
carbon film. Preferably, the process pressure is 19.95 Pa or below. Under such
process conditions for depositing a
fluorine-containing
carbon film by using the plasma, the source gas, such as C5F8 gas, is decomposed properly to form a structure of long CF chains. A interlayer insulation film thus formed has a small relative
dielectric constant and permits only a
low leakage current.