US Patent 7091133 Two-step formation of etch stop layer

A film is formed on a semiconductor substrate where a copper layer is to be formed and in contact with the film, by a method including the steps of: (i) introducing a first reaction gas comprising a deposition gas containing silicon, carbon, and hydrogen, and an inert gas, into a reaction space where a substrate is placed; (ii) depositing a silicon carbide film on the substrate by exciting the first reaction gas into a plasma; (iii) introducing a second reaction gas comprising a deposition gas containing silicon, carbon, and hydrogen, an oxidizing gas, and an inert gas, into the reaction space; and (iv) depositing a carbon-containing silicon oxide film on top of the silicon carbide film by exciting the second reaction gas into a plasma.