Patent ID: 7419916

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: (a) forming an interlayer insulator, including a porous film comprised of a SiOC material, over a semiconductor substrate having a conductive layer thereof, and then forming an alumina film, in which wiring trench forming regions are opened, over the interlayer insulator, wherein the interlayer insulator includes a cap insulator film formed over the porous film, wherein the alumina film is formed over the porous film; (b) after the step (a), performing dry etching to form via holes in the interlayer insulator by using a mask film; (c) after the step (b), removing the mask film and cleaning the inside of the via holes by using hydrofluoric acid; (d) after the step (c), performing dry etching with using the alumina film as a mask to form wiring trenches in the interlayer insulator; (e) after the step (d), removing the alumina film; and (f) after the step (e), forming wiring comprised of a conductive film having copper as a main component in the via holes and in the wiring trenches for electrically connecting the wiring and the conductive layer, wherein in the step (d) the dry etching is performed by using etching gas comprised of carbon and fluoride.