It is an object of the present invention to provide a laser irradiation
apparatus, a laser irradiation method, and a method for manufacturing a
semiconductor device using the laser irradiation method that can suppress
the energy distribution of the laser beam. The present invention provides
a laser irradiation apparatus including a laser oscillator oscillating a
pulsed laser beam, a lens assembly having a plurality of optical systems,
position control means for controlling the position of the lens assembly
to select at least two from the plurality of optical systems in
synchronization with oscillations of a plurality of pulses of the pulsed
laser beam, wherein the selected plurality of optical systems forms a
plurality of pulses with spatial energy distribution inverted or rotated.