| abstract |
(57) [Problem] To improve operation characteristics of a semiconductor device manufactured using a TFT and to reduce power consumption. A semiconductor film is irradiated with a first laser beam in an atmosphere containing oxygen to be crystallized, an oxide film formed by the first laser beam irradiation is removed, and then oxygen is removed. The first semiconductor film is formed by irradiation with the second laser light in an atmosphere which does not include the first semiconductor film. Further, a new semiconductor film is formed in contact with the first semiconductor film, and the semiconductor film is crystallized by being irradiated with a first laser light in an atmosphere containing oxygen. The oxide film formed by the irradiation is removed, and then irradiation with a second laser beam is performed in an atmosphere containing no oxygen to form a second semiconductor film. |