Plasma deposition method and system

There is provided a deposition technique wherein the amounts of eliminated F and H are small in the deposition of an insulating film, such as an SiOF film or an SiCHO film, which contains silicon, oxygen and other components and which has a lower dielectric constant than the dielectric constant of a silicon oxide film.A plasma processing system for producing plasma with the energy of a power applied between first and second electrodes which are provided in a vacuum vessel so as to face each other in parallel and which are connected to separate high-frequency power supplies, respectively, is used. An object to be processed, e.g., a semiconductor wafer is mounted on the first electrode. The frequency of the high-frequency power applied to the first electrode is set to be in the range of from 2 MHz to 9 MHz, and the frequency of the high-frequency power applied to the second electrode is set to be 50 MHz or higher, to deposit an insulating film on the wafer.