Abstract: A method for manufacturing a semiconductor device with high productivity is provided.

Abstract: A semiconductor device with little variation in transistor characteristics is provided. A first insulator to a third insulator are formed. A fourth insulator, a first oxide film, a second oxide film, a third oxide film, a first conductive film, a first insulating film, and a second conductive film are sequentially formed over the third insulator. Shaping them into island-like shapes to form a first oxide, a second oxide, a first oxide layer, a first conductive layer, a first insulating layer, and a second conductive layer. The second conductive layer is removed. A fifth insulator and a sixth insulator are formed over the fourth insulator, the first oxide, the second oxide, the first oxide layer, the first conductive layer, and the first insulating layer. An opening reaching the second oxide is formed to form a third oxide, a fourth oxide, a first conductor, a second conductor, a seventh insulator, and an eighth insulator. A fifth oxide, a ninth insulator, and a third conductor are formed in the opening.