Patent ID: 6849539

Claim:
A method of manufacturing a semiconductor device, comprising: forming a metal film and a first silicon nitride film laminated in this order over a semiconductor substrate on an insulating film; processing said first silicon nitride film and said metal film into a wiring pattern to form wires; depositing a second silicon nitride film on the entire surface such that said second silicon nitride film is applied to a top face and a side face of said first silicon nitride film processed into said wiring pattern, and side faces of said wires, and over the semiconductor substrate between said wires; forming a silicon interlayer insulating film of an oxide film to cover said second silicon nitride film; and forming a contact hole which reaches a surface of said semiconductor substrate between wires of said wiring pattern, comprising: forming an etching mask having a contact hole pattern on said silicon interlayer insulating film; penetrating said silicon interlayer insulating film between the wires by dry etching using said etching mask; and subsequently removing said second silicon nitride film over said semiconductor substrate at a bottom of the contact hole by dry etching, using said first silicon nitride film processed into said wiring pattern and said second silicon nitride film on the top and side faces of said first silicon nitride film and the side faces of the wires as an etching mask, wherein at least the dry etching of said silicon interlaver insulating film is performed with a nitrogen-containing gas added to a reactant gas comprising a fluorocarbon gas, a ratio of nitrogen to the reactant gas being 0.8 or more.