Patent ID: 7811910

Claim:
A manufacturing method of a flat display device for obtaining an active matrix substrate for use in a display device by placing a substrate with an amorphous semiconductor film or a granular poly-crystalline semiconductor film formed on the main surface thereof on a stage, and irradiating and annealing a plurality of regions of the amorphous semiconductor film or granular poly-crystalline semiconductor film on the substrate with a laser light shaped into a long and narrow beam while scanning the regions in a direction crossing the long axis direction of the shaped long and narrow laser beam to reform the amorphous semiconductor film or the granular poly-crystalline semiconductor film into a band-like poly-crystalline semiconductor film, the method comprising: monitoring a beam profile of the laser light on the substrate, calculating a maximum power density and a width of the short axis of the beam in the scanning direction from the monitored beam profile, and scanning and irradiating with the laser light at a constant speed while adjusting laser output based on the calculated maximum power density and the width of the short axis of the beam.