Laser irradiation apparatus, laser irradiation method, and method for manufacturing semiconductor device

Abstract: When the laser light having the harmonic is used for crystallizing the semiconductor film, there is a problem that the energy conversion efficiency from the fundamental wave to the harmonic is low. And since the laser light converted into the harmonic has lower energy than the fundamental wave, it is difficult to enhance the throughput by enlarging the area of the beam spot. The present invention provides a laser irradiation apparatus emitting the fundamental wave simultaneously with the wavelength not longer than that of the fundamental wave, typically the harmonic converted from the fundamental wave, wherein the laser light emitted from one resonator having the fundamental wave and the wavelength not longer than that of the fundamental wave are irradiated without being separated.