| abstract |
In a TFT using a crystalline semiconductor film of anbottom gate type, a gate insulating film is flattened. On ansubstrate, an underlying film, a gate wiring and a gateninsulating film are accumulated in this order. The gateninsulating film comprises a flattening film comprising anninsulating organic resin film, such as BCB, polyimide andnacrylic, and an insulating inorganic film. Because thensurface of the gate insulating film is flattened by thenflattening film, a flat amorphous semiconductor film can benformed on the surface thereof. Therefore, in the laserncrystallization, since no difference in focal point of thenlaser light is formed among each position of thensemiconductor film, crystallization can be uniformlynconducted. Because the edge part of the gate wiring can bencovered with the thick flattening film, implantation of annelectron or a hole to the gate insulating film, andnelectrostatic breakage of the gate insulating film can benprevented. |