Abstract: In a case where a CF film is used as an interlayer dielectric film for a semiconductor device, when a wiring of tungsten is formed, the CF film is heated to a temperature of, e.g., about 400 to 450° C. At this time, a F gas is released from the CF film, so that there are various disadvantages due to the corrosion of the wiring and the decrease of film thickness. In order to prevent this, thermostability is enhanced. A compound gas of C and F, e.g., C4F8 gas, and a hydrocarbon gas, e.g., C2H4 gas, are used as thin film deposition gases. These gases are activated as plasma to deposit a CF film on a semiconductor wafer 10 using active species thereof. Then, a hydrogen plasma producing gas, e.g., H2 gas, is introduced to be activated as plasma, and the CF film deposited on the wafer 10 is irradiated with the H plasma.

Abstract: This invention includes: a plasma-making step of making into plasma a film-forming gas including a compound of carbon and fluorine and an etching gas which can etch a film of fluorine-added carbon; and a film-forming step of forming a film of fluorine-added carbon onto an object to be processed by means of the plasma made in the plasma-making step. For example, the film-forming gas including a compound of carbon and fluorine includes a gas of a compound having a benzene ring. For example, the etching gas which can etch a film of fluorine-added carbon is a gas including fluorine. According to the invention, a concave portion can be satisfactory filled up with the CF film.