SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD

A semiconductor device according to one embodiment includes a stacked body including first films and second films that are stacked alternatively one on another, the stacked body having a stair shape at end portions thereof; a thick film portion thicker than the second films within the stacked body and provided on an upper surface of a first step of the stair shape; a separating portion provided on a side face between the first step and a second step one-step above the first step, the separating portion separating the thick film portion from the side surface; a third film provided to cover the stacked body and the thick film portion; and an electrically conductive column portion penetrating through the third film to be in contact with the thick film portion.