Patent attributes
In a semiconductor device in which transistors are formed in a plurality of layers to form a stack structure, a method for manufacturing the semiconductor device formed by controlling the threshold voltage of the transistors formed in the layers selectively is provided. Further, a method for manufacturing the semiconductor device by which oxygen supplying treatment is effectively performed is provided. First oxygen supplying treatment is performed on a first oxide semiconductor film including a first channel formation region of a transistor in the lower layer. Then, an interlayer insulating film including an opening which is formed so that the first channel formation region is exposed is formed over the first oxide semiconductor film and second oxygen supplying treatment is performed on a second oxide semiconductor film including a second channel formation region over the interlayer insulating film and the exposed first channel formation region.
