To provide a semiconductor device capable of forming a polysilicon superior crystallinity, and simultaneously preventing a substrate from being warped due to a high crystallization temperature at crystallization and a method for manufacturing the same.

The system implements a step that partially crystallizes an amorphous silicon layer, by evaporatively depositing a silicon layer containing the amorphous silicon on the substrate and performing annealing the silicon layer at a specific temperature in an H2O atmosphere; a step that forms a polycrystalline silicon film, by irradiating the partially crystallized amorphous layer with laser beam; a step that forms a gate insulating film on the polysilicon layer, and a step that forms a gate electrode on the gate insulating film. This prevents warpage of the substrate caused by the high crystallization temperature at the crystallization with the solid phase crystallization process of the amorphous silicon, and reducing defects is manufactured thin-film transistors.