A method of manufacturing a semiconductor device includes subjecting a semiconductor wafer, which includes a copper layer formed above a semiconductor substrate and covered with an insulating film, to a dry etching using a fluorocarbon gas to partially remove the insulating film, thereby at least partially exposing a surface of the copper layer. The copper layer, the surface of which is at least partially exposed is subjected to a nitrogen plasma treatment. The semiconductor wafer having the nitrogen plasma-treated copper layer is exposed to atmosphere, and then the semiconductor wafer is subjected to a surface treatment.