Laser processing method and laser processing apparatus

Abstract

A display device is manufactured by forming a semiconductor film over a substrate and irradiating the film with laser light. The laser light is generated from an oscillator, passes through an attenuator that includes a filter, and passes through an optical system after passing through the attenuator. A first region of the semiconductor film is irradiated with the laser light passed through the optical system such that one point of the first region of the semiconductor film is irradiated with at least two shots. A second region of the semiconductor film is also irradiated with the laser light passed through the optical system such that one point of the second region of the semiconductor film is irradiated with at least two shots. The first region and the second region have a portion at which they overlap, and the semiconductor film is etched into semiconductor layers for transistors in areas outside the portion.

1 . (canceled) 
     
     
         2 . A method of manufacturing a semiconductor device, comprising:
 forming a semiconductor film over a substrate, wherein the substrate includes a first device formation region and a second device formation region next to the first device formation region;   scanning the semiconductor film in the first device formation region with a laser beam elongated in one direction and having a first end and a second end opposite the first end along the one direction on an irradiation surface in a first direction, wherein both ends of the laser beam are located outside the first device formation region and the second device formation region;   scanning the semiconductor film in the second device formation region with the laser beam in a second direction, wherein the both ends of the laser beam are located outside the second device formation region and the first device formation region, and wherein the second direction is opposite to the first direction; and   dividing the substrate into a first sub-substrate including the first device formation region and into a second sub-substrate including the second device formation region,   wherein each length of the first sub-substrate and the second sub-substrate is shorter than a length between the both ends of the laser beam.   
     
     
         3 . The method of manufacturing a semiconductor device according to  claim 2 , wherein each of the first device formation region and the second device formation region contains thin-film transistors for driving picture elements and thin-film transistors constituting a peripheral driving circuit. 
     
     
         4 . The method of manufacturing a semiconductor device according to  claim 2 , wherein the semiconductor film contains silicon. 
     
     
         5 . The method of manufacturing a semiconductor device according to  claim 2 , wherein one end portion of the laser beam is located between the first device formation region and the second device formation region. 
     
     
         6 . The method of manufacturing a semiconductor device according to  claim 2 , further comprising a step of etching the semiconductor film into a plurality of active layers after the scanning step. 
     
     
         7 . The method of manufacturing a semiconductor device according to  claim 2 , wherein the laser beam is an excimer laser beam. 
     
     
         8 . A method of manufacturing a semiconductor device, comprising:
 forming an under film over a substrate, wherein the substrate includes a first device formation region and a second device formation region next to the first device formation region;   forming a semiconductor film over the under film;   scanning the semiconductor film in the first device formation region with a laser beam elongated in one direction and having a first end and a second end opposite the first end along the one direction on an irradiation surface in a first direction, wherein both ends of the laser beam are located outside the first device formation region and the second device formation region;   scanning the semiconductor film in the second device formation region with the laser beam in a second direction, wherein the both ends of the laser beam are located outside the second device formation region and the first device formation region, and wherein the second direction is opposite to the first direction; and   dividing the substrate into a first sub-substrate including the first device formation region and into a second sub-substrate including the second device formation region,   wherein each length of the first sub-substrate and the second sub-substrate is shorter than a length between the both ends of the laser beam.   
     
     
         9 . The method of manufacturing a semiconductor device according to  claim 8 , wherein each of the first device formation region and the second device formation region contains thin-film transistors for driving picture elements and thin-film transistors constituting a peripheral driving circuit. 
     
     
         10 . The method of manufacturing a semiconductor device according to  claim 8 , wherein the semiconductor film contains silicon. 
     
     
         11 . The method of manufacturing a semiconductor device according to  claim 8 , wherein one end portion of the laser beam is located between the first device formation region and the second device formation region. 
     
     
         12 . The method of manufacturing a semiconductor device according to  claim 8 , further comprising a step of etching the semiconductor film into a plurality of active layers after the scanning step. 
     
     
         13 . The method of manufacturing a semiconductor device according to  claim 8 , wherein the laser beam is an excimer laser beam. 
     
     
         14 . The method of manufacturing a semiconductor device according to  claim 8 , wherein the under film is silicon oxide.