Patent ID: 7208358

Claim:
A method of manufacturing a thin film transistor comprising: forming a semiconductor film including amorphous silicon having a thickness of 150 to 1000 Å over a substrate; emitting a pulse laser light at a rate of N pulses per second; shaping the pulse laser light into a beam having a cross section perpendicular to a propagation direction of the beam, said cross section having a width and a length, wherein the length is longer than the width, wherein the beam has a normal-distribution type energy profile of width L (m) perpendicular to the length direction, where L is larger than zero, and the beam having substantially a constant energy distribution along a lengthwise direction; applying the beam to a portion of the semiconductor film; and scanning the semiconductor film with the beam perpendicular to the lengthwise direction of the cross section at a speed V (m/s) in order to crystallize said semiconductor film, wherein the number of beams applied to said portion in one scan satisfies a relationship 3≦LN/V≦100, and wherein the width L (m) is defined as a beam in a region having 5% or more of an energy density with respect to a maximum energy density of the beam on the irradiation surface.