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

A laser irradiation apparatus comprising:

• a first laser oscillator generating a first pulsed laser beam having a wavelength of visible light or a shorter wavelength than that of visible light;
• means for controlling a shape and a position of a beam spot of the first laser beam;
• a second laser oscillator generating a second continuous wave laser beam of a solid laser, the second continuous wave laser beam has a fundamental wave;
• means for controlling a shape and a position of a beam spot of the second laser beam to overlap with the beam spot of the first laser beam, the means functioning such that the beam spot of the first laser beam is larger than that of the second laser beam;
• and
• means for controlling a relative position of the beam spot of the first laser beam and the beam spot of the second laser beam to a processing object.

A method for manufacturing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• and
• irradiating the semiconductor film with a first pulsed laser beam having a wavelength of visible light or a shorter wavelength than that of visible light and a plurality of second continuous wave laser beams of solid lasers, each of the plurality of second continuous wave laser beams has a fundamental wave to crystallize the semiconductor film,
• wherein when the semiconductor film is irradiated with the first laser beam and the plurality of second laser beams, a portion of a first beam spot formed on a surface of the semiconductor film by the first laser beam and an entire portion of a plurality of second beam spots formed on the surface of the semiconductor film by the plurality of second laser beams are overlapped with each other.

A method for manufacturing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• and
• irradiating the semiconductor film with a first pulsed laser beam having a wavelength of visible light or a shorter wavelength than that of visible light and a second continuous wave laser beam of a solid laser, the second continuous wave laser beam has a fundamental wave to crystallize the semiconductor film,
• wherein when the first laser beam and the second laser beam are irradiated, a beam spot formed on a surface of the semiconductor film by the first laser beam and a beam spot formed on the surface of the semiconductor film by the second laser beam are overlapped, and
• wherein the beam spot of the first laser beam is larger than that of the second laser beam.