Patent ID: 6555423
Filing Date: 2003-04-29
Classification: B23K,H01L

Abstract:
A method of manufacturing a thin-film transistor, in which a laser annealing apparatus anneals an amorphous silicon film and converts the amorphous silicon film to a polysilicon film that serves as a channel layer, said method comprising the steps of:forming a metal pattern on a substrate; forming an amorphous silicon film on the substrate, thereby covering the metal pattern; performing laser annealing on a plurality of parts of the amorphous silicon film formed on one or more substrates at different energy densities of a laser beam, thereby forming a polysilicon film; evaluating, in numerical value, a surface spatial structure of a part of the polysilicon film that lies above the metal pattern; evaluating, in numerical value, the surface spatial structure of other parts of the polysilicon film; calculating a difference between the numerical value of the part of the polysilicon film that lies above the metal pattern and the numerical value of the other parts of polysilicon film; and controlling the energy density of the laser beam or the thickness of the polysilicon film by using the calculated difference as a control parameter for controlling the energy density and the thickness of the polysilicon film, wherein linearity and/or periodicity of the surface spatial structure of the part of the polysilicon film that lies above the metal pattern is evaluated in a numerical value, and a linearity and/or periodicity of the surface spatial structure of the other parts of the polysilicon film is evaluated in a numerical value.