An object of this invention is to provide a semiconductor device manufacturing method in which a semiconductor film is formed over a substrate, the semiconductor film is crystallized by irradiating a laser light, a silicon oxide film is formed in contact with the crystalline semiconductor film by using organic silane, a gate electrode is formed in contact with the silicon oxide film, an impurity element is introduced into the crystalline semiconductor film, the impurity element is activated, an interlayer insulating film is formed over the gate electrode, and then a wiring comprising aluminum is formed over the interlayer insulating film.