A semiconductor device including a transistor and a wiring electrically connected to the transistor each of which has excellent electrical characteristics because of specific structures thereover is provided. A first conductive film, a first insulating film over the first conductive film, a second conductive film over the first insulating film, a second insulating film over the second conductive film, a third conductive film electrically connected to the first conductive film through an opening provided in the first insulating film and the second insulating film, and a third insulating film over the third conductive film are provided. The third conductive film includes indium, tin, and oxygen, and the third insulating film includes silicon and nitrogen and the number of ammonia molecules released from the third insulating film is less than or equal to 1×1015 molecules/cm3 by thermal desorption spectroscopy.