| abstract |
(57) [Summary] An object of the present invention is to realize an increase in crystal grain size of a crystalline semiconductor film formed by a laser crystallization method. It is an object of the present invention to manufacture a TFT from the crystalline semiconductor film and obtain reliability comparable to that of a MOS transistor. A thermal insulating layer is formed between a semiconductor film and a substrate in order to increase the crystal grain size of a crystalline semiconductor film manufactured by a laser crystallization method, and further, a thermal insulating layer is formed on the semiconductor film. Is formed to slow down the cooling process of the semiconductor film heated by the irradiation of the laser beam. Since the crystal growth distance is proportional to the product of the growth time and the growth rate, the cooling rate is slow and the growth time is long, so that a large grain size can be realized. |