Method of manufacturing a semiconductor device and a process of a thin film transistor

Abstract

To enable radiating an optimum energy beam depending upon the structure of a substrate (whether a metallic film is formed or not) when an amorphous semiconductor film is crystallized and uniformly crystallizing the overall film, first, a photoresist film and the area of an N + doped amorphous silicon film on the photoresist film are selectively removed by a lift-off method. Hereby, the amorphous silicon film is thicker in an area except an area over a metallic film (a gate electrode) than in the area over the metallic film. In this state, a laser beam is radiated. The N + doped amorphous silicon film and an amorphous silicon film are melted by radiating a laser beam and afterward, melted areas are crystallized by cooling them to room temperature. As the amorphous silicon film is thicker in the area except the area under which the metallic film (the gate electrode) is formed than in the area under which the metallic film is formed, the maximum temperature of the surface of the film is equal and the overall film can be uniformly crystallized.

1 - 15 . (canceled)  
   
   
       16 . A method of manufacturing a semiconductor device, comprising: 
 forming a gate electrode on a portion of a top side of a substrate, said gate electrode being a metallic film;    forming an insulating film on said substrate and said gate electrode;    forming a lift-off film on said insulating film wherein said lift-off film is a photoresist;    forming an N +  doped amorphous semiconductor film with a uniform thickness on said photoresist and said insulating film wherein said uniform thickness of said N +  doped amorphous semiconductor film is a function of a thickness of said insulating film;    irradiating said photoresist from a rear side of said substrate;    removing said photoresist film and said N +  doped amorphous semiconductor film on said photoresist;    forming an amorphous semiconductor film on said N +  doped amorphous semiconductor film and said insulating film;    irradiating said amorphous semiconductor film and said N +  doped amorphous semiconductor film with an energy beam with a set optimum value of energy required for crystallization;    uniformly crystallizing said amorphous semiconductor film and a residual area of said N +  doped amorphous semiconductor film by cooling them to room temperature, wherein a thickness of said amorphous semiconductor film is thicker in an area over said metallic film than in an area not covering said metallic film, and a temperature at a surface of said crystallized amorphous semiconductor film and said N +  doped amorphous semiconductor film is substantially equal; and    forming source and drain electrodes in predetermined positions on said amorphous semiconductor film and said N +  doped amorphous semiconductor film.