Semiconductor device comprising oxide semiconductor

A semiconductor device comprising:

• an oxide semiconductor film over an oxide insulating film;
• a gate insulating film over the oxide semiconductor film;
• a gate electrode layer over the gate insulating film overlapping with the oxide semiconductor film;
• an insulating film including an aluminum oxide film covering an entire top surface and an entire side surface of the gate electrode layer;
• an interlayer insulating layer over the oxide semiconductor film, the gate insulating film, the gate electrode layer, and the insulating film including the aluminum oxide film, wherein an opening reaching the oxide semiconductor film is provided in the interlayer insulating layer;
• and
• a wiring layer in contact with the oxide semiconductor film and a top surface and a side surface of the insulating film including the aluminum oxide film, the wiring layer being provided in the opening,
• wherein the interlayer insulating layer is in contact with a top surface and a side surface of the oxide semiconductor film and the top surface of the insulating film including the aluminum oxide film, and
• wherein the insulating film including the aluminum oxide film is in contact with the top surface of the oxide semiconductor film.